Hospital Hop...how to stop it?

[Capt. Crash]

Newbie question for all you hydroplane guru's.

My UL-1 starts a sponson to sponson wobble and sometimes gets worse and more violent until I have to let off. Some times it straightens itself out... but usually it doesn't.

What is the cause and cure for this condition?

Is this caused by being too light on the sponsons?

Do I need more weight forward or more prop depth?

BTW...I heard Darrel Waltrip (I think it was Darrel) talk about a car on the brakes too hard while getting into the corner too hot making the car hop up and out and hit the wall. He called this hop the "Hospital Hop" because that's where it lead too!

I call the sponson to sponson wobble the same thing cause that's where your boat is going to end up if you don't let up. :cursing:

Thanks for the help guys...maybe I'll quit bugging ya someday....probably not though...cause we now have 3 of these new boats in the club and several more saying they are getting them....and nobody knows what there doing! :popcorn2:

[Darin Jordan]

The first place on a Hydroplane that I suspect as being an issue is always the turn fin. Perhaps make yourself a STRAIGHT turn fin and give that a try. If the problem goes away, then you know where to start tweaking... Also make sure that it's aligned correctly, parallel to the centerline of the boat...

I'm not a big fan of curved turn-fins... They can work great, but can also be a REAL headache until you get them just right...

If that doesn't seem to cure it, then I'd look at the sponsons next... are they flat?? REALLY FLAT?? If you look at the pictures of my project boat, even though they appeared flat, a light sanding revealed some decent troughs down the center of the one sponson... This can cause the sponsons to suck down, then release, then such down, then release... Not good... MAKE THEM FLAT! Some block sanding and filler primer and block sanding again should take care of that for you... the other sponson on mine was REALLY flat, so just a little attention here needed... No need to go to the trouble of ride-pads if you don't mind taking the time to sand...

Just my $0.02...

[AndyKunz]

It could also be caused by an incorrect angle on the prop. You want the prop to push the nose down (but not too far down). If the angle is wrong, it's going to lift the bow and force air under the hull. The air has to come out somewhere, so the boat rocks left and right to let it blow out the sides. An air dam prevents the air from getting under there in the first place.

It could also be related to the design. If the air stays trapped under the hull too far back it will do the same thing. You need to allow the excess air to vent. This could be accomplished by removing the tunnel sides on the afterplane a little or by moving the sponson transom forward (that's the design solution, not the fix for something you already are driving).

Another possibility is that the angle on the forward portion of the tunnel is too steep. This lifts the bow. On my designs I use a shallow angle and run it farther down the boat, resulting in a lower pressure gradient and smoother operation.

Any chance you could get a video of it doing this? Some of it is normal - you might be seeing something normal and not realize it.

Hope this helps.

Andy

[Darin Jordan]

There I go, ignoring basic setup tweaks again!

I made the assumption that you had already tried various strut positions... Can't overlook the basics! (Like I seem to do from time to time... ;) )

[Capt. Crash]

Any chance you could get a video of it doing this? Some of it is normal - you might be seeing something normal and not realize it.

Hope this helps.

Andy

We don't normally have anyone taking pics except me and I don't have a way to take video.

The "Hospital Hop" usually starts as a result of crossing my own wake from a previous pass. Once started...it usually, but not always, stays the same or gets more violent until I let off. When I ran with the air dam it still did it. The only difference I saw with the air dam was slightly slower speed...but this was a limited set of tests....3 runs with it on and 2 different props and strut settings. I will try it with the 40X57 prop 1/8" lower next run putting it at 1 1/8" from the bottom of the hull to the bottom of the strut measured with the boat on a flat surface, with out the dam.

At what speed do we need the air damn with this boat? :confused2:

[Capt. Crash]

There I go, ignoring basic setup tweaks again!

I made the assumption that you had already tried various strut positions... Can't overlook the basics! (Like I seem to do from time to time... ;) )

Yes...that's one of my questions above...will more prop depth fix this?

[Darin Jordan]

It's not just depth, but also angle... I haven't run mine yet so I can't give you good answers... I've read to the effect that 1 1/6" of depth with a 3-degree downward angle works... I think that was Tony's setting (Properchopper)...

[Capt. Crash]

It's not just depth, but also angle... I haven't run mine yet so I can't give you good answers... I've read to the effect that 1 1/6" of depth with a 3-degree downward angle works... I think that was Tony's setting (Properchopper)...

Oh boy...I must have missed the angle setting part of this adventure! :sorry:

That poses new questions!

Which way is down? Prop wash shooting down?

What do you use to measure the angle?

How do you orient the boat and take the measurement?

Hey just how is this done? :help:

[Darin Jordan]

Down means prop is thrusting downward... Front of strut is slightly higher that the back...

The way I set a strut initially is to remove the rudder and turn fin, then set the boat on a flat surface. I set everything from there... Set your depth (1 1/16"???), then adjust your angle (raise the front of the strut slightly until you get 2 or 3 degrees??)

To measure it... why not make yourself a shim from a piece of scrap wood... Sand it to the angle you want, then slid it up to the strut and set the angle...

I usually just eyeball it... until I get it where it runs well... Then I measure it after that with a protractor...

[Capt. Crash]

Thanks for all the great help here guys...one more question...if you had to guess...how far off the flat surface would the end of the strut (not propshaft) be @ 3 about degrees (in inches please)? or...how much air is there between the surface and the end of the strut....1/8" more...less?

[detox]

.030" max (front of strut to table) is what I have read. Going over this setting may cause stern (rear) to hop...unless you bend your prop.

[egneg]

This is what fluid said to do and I have about the same setup but at maybe 2 degrees down and no hop. When I was at 1" and 3 degrees I had some hop.

Fluid: My TP5000s weigh 9 ounces each, and I have no problems getting up on plane. Brian wasn't using light weight cells at the SAWs and his never subed. I suspect that the problem most guys are having is with the strut setting. Hydros are not like monos...
The bottom of my strut came 7/8" below the hull and angled at most 1 degree down at the prop end. If you are having trouble getting on plane you can simply flatten the strut. You do not want to angle the strut any more or you'll never get on plane! A flat strut is the default setting; if the bow flies then angle it down a bit at the prop end. It won't take much. If the boat runs too hard on the water raise the strut 1/8". Several guys have e-mailed me about problems getting up on plane, and in every case a minor strut adjustment was all it took regardless of the packs used.
Different props can cause trouble getting on plane too. Screw on a lifting prop combined with too much strut angle and you'll never get on plane. If you are using a lifting prop, flatten the strut. You may even need to run the strut up a degree at the prop end. "Best" all-around prop may be an m445 or K45. It will take some additional testing to find out for certain. The x442 is pretty small - doubt it has enough blade area to load the motor enough.
BTW all strut adjustments must be done on a flat surface like a table. The hydro should rest on the sponsons and the strut. The strut angle will be between the bottom of the strut and the tabletop. Don't try to do it "by eye", it won't work.

[detox]

Fealer gauge works great along with a flat piece of 3/4" MDF board. I attached three rubber non slip pads on the bottom of my 3/4 MDF setup board.

[Capt. Crash]

A feeler gauge I have...I must be getting tired...I dont know why I was thinking a gap at the back of the strut.

Ok...now I think I'm ready to go to the barn! :doh:

[detox]

Raptor has experimented with good success.


Hey guys, I finally got my hands on a computer.

The UL-1 really suprised me. I put an M445 on it for it's first pass, I flew it off and tumbled through the traps at 45mph. So I had a rough baseline. Next pass was with an M645 and 3/16" deeper on the strut, 52mph with a good ride attitude but still too light on the sponsons. 3rd pass was with a modified 2047 and a 1/2" deep tape air dam in the tunnel, 59mph pedaling it through the lights. Final pass was the same prop and air dam but 3/32" deeper on the strut, 65.7mph with a high 64mph return run. Temps on the final 2 passes were: motor 114F, ESC 126F, battery 109F (it had cooled down).

Stock motor/esc/hull. I didn't even touch the sponson bottoms. Total mods from out of the box: remove turn fin and vertical fins, tape air dam, strut adjustment and a fairly trick octura 2047. I did run my Futaba FASST 2.4G radio.

Then I put the turnfin back on with a 38x55 grimracer prop and ran 41mph for 8 minutes in rough water. I LIKE IT!!!

After the SAW passes

[JimClark]

Another thought is the CG a little too far back. I assume if you were to let it go it would blow over? Sounds like you are running on the ragged edge?
Jim

[Capt. Crash]

I've not had it try to lift.

Here is the set up. 1 1/16" from hull to bottom of strut (table). Where do I measure the angle....at the end of the taper (yellow dot) fore or where the taper starts (red dot) aft. How does this angle look?

[Grimracer]

wow.. that’s a ton of strut angle..

I use a digital level and a rod in place of the stub shaft the check the shaft.

The hull over all is very solid and the numbers are good..

Remember the boat had to work for all pilots..

Andy.. just so you know.. and im sure you do.. to low or flat a break angle and the boat can blow off with 0 warning. .. personally I hate that.. I would rather have the boat wiggle or something to let me know something bad is about to happen. Gives one time to get her back on the water and FINISH THAT HEAT… very important.

What I was going for was a 40 to 50 mph heat race boat.. Bottom line..

Grim

[Grimracer]

o yea.. Capt. just so you know its called Chine Walk.

ROCK ON and keep testing!

Grim

[detox]

Measure at the red dot using fealer gauge, but like Grim said...that is probably too much angle.

Why do you have wire in the rudder adjustment hole? Do you run the boat with wire in that location?

[Grimracer]

racers,

every time we start talking handling Brians post comes back regarding his SAW run..

DO NOT EXPECT YOUR BOAT TO HEAT RACE AT THAT SET UP.. and please do not START THERE. I personly have NEVER ran the strut that deep.. as I go faster I might but to set the boat.. never..

Start with the strut set where its at from the factory.. if you want to change it (and I recomend it depending on the prop) do it after the first few runs.

Starters.

Set the strut at 15/16"
Set the strut flat on the setup board, I see you have the L40x57/3. Better yet lets start with the 40x52/3.. Just a note.. the L38x55 - 63 and the new L40x57/3 were designed around 0 strut angle.. having said this you MIGHT? have to cup slighty to remove some lift.
Round or shapren the bottom of the rudder
Set the turn fin so the top break is parrell to the foot print with your 15/16" strut height. My setup board has marker lines on the side of it for this.

Test and report.

As a side not.. I do not like turn fins that enter the water at an angle.. and.. truth is that is why the fin is the way it is. its a smaller version of my US-1 Ninja fin with a slight change to the LE..

Grim

[properchopper]

I should be able to report on the before & after results of Darin's ride-pad installation. Both to flatten out the surface & help re-inforce my turn-fin fix I did the G-10 thing today. I'll leave all other settings the same & should get some runs in Sunday & post. :smile:

[Capt. Crash]

Measure at the red dot using fealer gauge, but like Grim said...that is probably too much angle.

Why do you have wire in the rudder adjustment hole? Do you run the boat with wire in that location?

My boat came with an almost flat thrust setting and it runs pretty nicely with the 40X52/3 prop at that setting (43mph)...but I couldn't get on plane with the 40X57/3 until I lowered the prop to 1"....now it "Chine Walks" a little too much for my liking.

The brass rod is a thin shear pin. I keep the rudder bolt tight enough that the rudder does not move unless I hit something. I've had the rudder swing up to the shear pin after hitting sticks, buoys and a probable turtle but there wasn't enough force to shear the pin. The pin stops the rudder deep enough in this situation to allow enough control to get the boat back in. It's worked great so far. REMEMBER...I'm only sport racing here....and have among other things big mean Aligator Snapping Turtles to contend with.

As for the thrust angle...I was thinking that the angle I set in the pic was not going to be enough based on the 40X57/3 prop with the 1 1/16" setting. Ya'll think it's too much?

With it set here and no air dam it what should it handle like?

oh...and exactly where should my CG be?

[Capt. Crash]

Round or shapren the bottom of the rudder

So you don't want a factory fresh squared off rudder?

Set the turn fin so the top break is parrell to the foot print with your 15/16" strut height. My setup board has marker lines on the side of it for this.

Grim

Can ya elaborate on this some more with a illustration?

[AndyKunz]

Andy.. just so you know.. and im sure you do.. to low or flat a break angle and the boat can blow off with 0 warning. .. personally I hate that.. I would rather have the boat wiggle or something to let me know something bad is about to happen. Gives one time to get her back on the water and FINISH THAT HEAT… very important.

Mike,

There's a solution to that, too. Get yourself an original UL-1 and you'll see it. You end up with a MORE stable boat.

Andy

[Grimracer]

Andy..

What?

Grim

[Grimracer]

Wait wait wait.. i get it I get it i get it...

Andy... How does that post help Capt. Crash.. Well.. it doesn’t.. It does not help him in anyway..

So Andy what are you really saying with that post?

Sounds again like just spuing info for the good of Andy and his master design the "Original UL-1"…. I detect a sore spot in there..

Capt. Please just read through that stuff bud.. we will get your boat rocken. Yea.. its best to Always round or sharpen the bottom of your rudders.. just standard issue on my race boats.. ya buyem square and sharpen..

Andy.. play this game the way you see fit.. I can tell you now however.. Im not the kind that’s going to comment on how your designs for Proboat work. Its just tacky and not all that professional.. especially when you work for a company (Horzion) that makes products that are in direct competition with ours. Im not going to do that to your boats.. but again its your head.. do as you please.

ROCK ON UL-1 Drivers.. lets get some heat wins.

Grimracer

[Capt. Crash]

....ummmm.....back to my questions at the end of post #23 please. And can ya show me what you mean about the turn fin setting with a pic or drawing.

Thanks


(I didn't know Andy is affiliated with Pro Boats)

Youz guz need to duke it out with your products on the field of battle...not this thread please! :tape:

[properchopper]

ROCK ON UL-1 Drivers.. lets get some heat wins.

Grimracer

Mike, there's EIGHT LSH entries so far at WW V [which allows UL-1's].
Besides myself, only one other racer reports using a 2.4 radio so I'm assuming one or two UL-1's in the class. I'm pretty focused on doing the deal, testing & tuning my a** off . The driver lineup is all totally top notch excluding myself, but
anything can happen :thumbup:
[ BTW my VS-1 is poised & ready as well. 7 OPC entries so far also :buttrock:]

Tony

[Darin Jordan]

Yea.. its best to Always round or sharpen the bottom of your rudders.. just standard issue on my race boats.. ya buyem square and sharpen..

Mike,

That's so the bottom of the rudder doesn't become a planing surface, right??


I should have noted above... I almost ALWAYS start out with my struts... all of my struts (monos and Hydros) flat... then tune from there... Otherwise, you can end up fighting a self-induced problem... Plus, it puts all of the thrust pointing in the direction it needs to be pointed!! ;)

[Doby]

Wait wait wait.. i get it I get it i get it...

Andy.. play this game the way you see fit.. I can tell you now however.. Im not the kind that’s going to comment on how your designs for Proboat work. Its just tacky and not all that professional.. especially when you work for a company (Horzion) that makes products that are in direct competition with ours. Im not going to do that to your boats.. but again its your head.. do as you please.

ROCK ON UL-1 Drivers.. lets get some heat wins.

Grimracer

So Andy works for ProBoat?

If true, it would be nice to know who is affiliated with what company so any advice/ comments can be weighed appropriately.

[Grimracer]

....ummmm.....back to my questions at the end of post #23 please. And can ya show me what you mean about the turn fin setting with a pic or drawing.

Thanks


(I didn't know Andy is affiliated with Pro Boats)

Youz guz need to duke it out with your products on the field of battle...not this thread please! :tape:

lets see here.. if this works on this old dog..... sorry about the ugly pic.. its just to get the point across.

Grim

[Capt. Crash]

...that is a big help.....now one more time....where exactly should the CG be with the boat buttoned up and ready to terrorize the pond. :huh:

Crash

[Capt. Crash]

Mike,

That's so the bottom of the rudder doesn't become a planing surface, right??




That's a mighty small planing surface! I'd think it might have more to do with turbulence created there. :popcorn2:

[Bill-SOCAL]

So Andy works for ProBoat?

If true, it would be nice to know who is affiliated with what company so any advice/ comments can be weighed appropriately.

Well in the interest of full disclosure then, I am a member of Team Futaba (Air) as a Field Representative. I am not paid, receive no other compensation and pay for everything I get (but I do get a decent discount). I do get free service (hardly ever need it :thumbup: ) and a free Team Shirt each year. Sadly some think that we Team members will compromise our integrity for the sake of that free shirt.

Oh well. Like my signature says on another forum - "Ignore me - I get a free shirt!!"

[Grimracer]

Capt.

Setting the CG at 3 to 3 1/4" back from the sponson backs will get you very close. Typically on a good race boat the CG is around the center of the back of the turn fin. One of the reasons my turn fin design is swept.. allows better turning on a wider CG range.

The bottom of the rudder can make lift.. more then you think.. also remember to sharpen the rudder.. (lift lift lift)


Grim

[Darin Jordan]

The bottom of the rudder can make lift.. more then you think.. also remember to sharpen the rudder.. (lift lift lift)


Grim

Thanks Mike... that's what I thought... I recall reading that in an article on making Monos work (I think by John Finch??? )...

[Capt. Crash]

Lot's of good stuff in here to help me and the lurkers out there....you know who you are! :spy:


Thanks again everyone.

[detox]

Mike, Good info concerning prop, turn fin, COG, and rudder sharpening .............THANKS!

While sharpening the rudder you will notice water intake hole plugged at bottom of rudder (red arrow) with what looks like epoxy. Be sure to plug this area again using epoxy (JB Weld) if port is exposed after sharpening. I removed red area of turn fin only.

[Jeff Wohlt]

Some of the Chine walk can be attributed to flat sponson design with too much angle. You may be getting your walk from the light front end and the motor/blade torque as the front is light it will try and twist the boat to the right then it reacts after hitting water and then the reaction occurs...left side hits and pushes it back up. No doubt this is a faster design than a low angle sponson but handling will be the issue in certain water conditions. You are packing a lot of air in that hull riding high in the front but the tail also rides pretty high so I doubt that the hull is not exiting the air.

Are you running the 3 blade prop?

As Grim noted...that strut angle is waaaaay off but that will push the nose down and make the sponsons run wet. You have to have a certain amount of area that is in contact with the water. Should be fine on smooth water but waves or other boat wash will make it hard to handle.

[AndyKunz]

So Andy works for ProBoat?

If true, it would be nice to know who is affiliated with what company so any advice/ comments can be weighed appropriately.

No, I work for Spektrum supporting aircraft stuff almost exclusively. I own a Miss Elam and hope to get it on the water as soon as it melts.

For the record, I also told Mike at the IHobby show that it's a really nice looking boat and I would like to have one. He might think I'm dissing him, but I'm not. I just happen to come from a different school of Sport/Scale hydroplane design.

Andy

[Capt. Crash]

Are you running the 3 blade prop?


Yes...that's all I've run. The stock prop and setup did not do the Chine Walk...the 40X52/3 and stock setup (7/8" depth) does and so does the 40X57/3 @ 1"strut depth. I've not tried the setup I took the picture of (1 1/16" depth)...it was next on my agenda. I may have try it just to see how she runs.

Thanks for the explanation on the reason for the Walk...that makes sense to me.

[Capt. Crash]

Some of the Chine walk can be attributed to flat sponson design with too much angle. You may be getting your walk from the light front end and the motor/blade torque as the front is light it will try and twist the boat to the right then it reacts after hitting water and then the reaction occurs...left side hits and pushes it back up.

I just checked my Center of Gravity and it appears I was tail heavy. I'm sure the 3 oz GPS isn't helping by being aft. I moved it up between the batteries and slid the packs all the way forward and I am just about balanced right. I wish the ESC wires were just a little longer. I have to lay the connectors on top of my GPS window...that's why I went AFT in the first place. I may move the ESC forward a little to fix this. My 5250s only weigh in @ 241 grams each so the movement of things forward should help compensate.

[LuckyDuc]

Good stuff gents! Like Capt said... When possible, please post illustrations/pics for us noobs. It helps us visualize the advice better.

[LuckyDuc]

BTW I really appreciate the info on the location for the C of G range.

[Jeff Wohlt]

All I know to weigh about Andy's info is his past boat experience... many years, creating a nice UL1 hull for the LSH class, electronic excellence, One of the best ESCs ever made for brushed motors, Flying and building planes, designing an adapter for plane ESC to pistol adapter so we can use other ESCs.

Besides that....he seems to be almost normal!! :rockon2:

I still have one original UL left I may build with the New UL1 motor/ESC and prop and see how she does. I won't claim it will be as fast because of sponson design but it handles rough racing waters well....at least mine did and I also put ride pads on it. Gotta finish to get any points!! Wish I could make one out of glass...guess I could.

[Capt. Crash]

Would someone tell me what the scale of these boats are...1:32?

[Bill-SOCAL]

A typical hydro is about 30 feet long. The UL-1 is a little over 2 feet (27 inches). So pretty close to about 1/12th scale give or take a little.

30 feet = 360 inches

360/27 = 13.33

[Capt. Crash]

Wow...I a was a little off! Of course that happens when ya get old....I went the wrong way when comparing to some of my other boats....:doh:

Thanks

Got me some new hyroplane friendly buoys made up last night and am ready to rock Saturday. :popcorn2:

[Grimracer]

Capt..

The buoys we use are made by Kershaw floatation in FL.

They are 12” foam spheres that one cuts in half. The great thing about these buoys is that they are firm but not hard. They lay flat on the water.. The boat does more glancing then hitting.. you have to hit them dead straight on to damage anything and truth is I have only ever broke a outrigger on one of these as they have a tendency to launch the boat…not grab it.. Any of this make since?

I have never seen this type of buoy at a FE race and I have always wondered why? Anybody help.. Maybe I am missing something?

Anywho…

ROCK ON

Grim

O yea.. one more thing.. the club paints the buoys.. the reason this is done as when struck it leaves a paint witness on the boat.. great info if needed for the CD.. Just make sure you clean it off before the next race..

[Bill-SOCAL]

Which brings me to the dumbest rule in all of NAMBA, that brushing a buoy is the same as cutting it.

Maybe the solution is to make them absolutely solid so if you hit one you sink!!! Touching it ends the race for you anyhow in most instances since you lose a full lap (another thing I do not understand, why not a points penalty, but ONE FULL LAP!! - WOW)

[Fluid]

The one lap penalty was originally to keep drivers more focused and paying attention to the position of their boat on the course. With only a 50-point penalty some racers would cut a buoy to win too. While I prefer the 50 point penalty I'll abide by the sponsoring body at each race.

Bill, I do not know where you found the NAMBA "rule" that brushing a buoy is the same as cutting it. Here is what the rule book says:

DRIVING RULES AND REGULATIONS: D.3.a.
"A one lap penalty will be assessed when a boat cuts inside a course marker or
when the boat jumps over or makes an obvious hit on a buoy. No penalty will
be assessed for a boat that touches a buoy on the outside causing no damage
or displacement.'

You are not alone in ignorance of this rule. I remember an out-of-town racer who was assessed a lap penalty at an FE Nationals because a local turn marshal "heard" his boat hit a buoy....he did not see it but the CD still allowed the penalty - after the end of the heat! Now THAT was BS.....



.

[Bill-SOCAL]

Every NAMBA race I have ever been to, including the 2008 FE NATS used that as the rule. A touch is the same as a cut. I think that kicker is the interpretation of "displacement". People see that as meaning if the buoy is seen to move, even bobble in place, then it violates the rule and gets the one-lap penalty.

This contradiction in this is apparent, saying that the buoy was brushed but not displaced is the same thing as saying you can touch it as long as it doesn't appear that you have touched it.

I guess I need to look closer at the book and challenge that rule the next time. I guess we will need clarification on what constitutes "displacing" the buoy. To me that means moving it out of its location, not just making it bobble in place. Your wake displaces the buoy as well. See, the devil is in the details.

Jay wrote:

You are not alone in ignorance of this rule.

Sadly nearly every racer in my District shares my ignorance. Or at least shares my inability to distinguish between a touch and something more.

FWIW I just sent off an email to AL Waters (NAMBA President) asking about this. Basically where is the line between touching/brushing and "displacement"?

[AndyKunz]

It's at the discretion of the CD.

Andy

[Bill-SOCAL]

Andy is correct. As I said, I sent an email to Al Waters, the President of NAMBA. Here is his response.


Bill,
You are reading the NAMBA rules. Here is one for you. D19 rule since 1991 is
no brushing or touching.

You typed................
************************************************** **************
Every race I have been to interprets this rule to mean that if you touch
a buoy then you have displaced it thus you get the penalty.
************************************************** *********************

Not true.......if you have displaced a buoy then you have touched it. You
have it backwards. Displaced means that it is in a different location than
its original location. It is then up to the CD to determine if it was done
by the boat or the boat wake. Buoy penalties are no different than jump
starts.........it s discretionary call by the CD.

If you don't want to get called for a jump start, don't be so close to the
start line.....................If you don't want to get called for a buoy
penalty, don't get too close to the buoys.........

Thanks, Al


Al missed that I was asking about the general NAMBA rules. Here in District 19 Jay, we have this rule:


3-91 Brushing or touching of buoys will result in a lap penalty.

So in my District we follow the most restrictive possible interpretation of it. hence my earlier statement that I have never been to a NAMBA race that does not use the you touch it you get a penalty rule.

[Doug Smock]

Tough crowd Bill!!

[Ub Hauled]

I was thinking about "the hop"...
Tony's UL did the same thing in the beginning,
looking back I believe it was a combination of factors...
first it was a little lose and started flying and then the first sponsons
would take off and land hard rebounding and throwing the hull to the other side
and so the hop started, violently like described earlier. The reason
it started bouncing side to side like that and get worst, is because the
turn fin would hit the water at an angle and push the hull
up to the other side again and then the vicious cycle would start
over and over again... if you can keep her nose down this dance
probably would not happen.

just my shot at it...

[properchopper]

We'll see how Darin's G-10 ride-pad addition affects things Sunday [early]. I agree with Jeff that torque reaction has a large contribution to the dance ; the three blade 40/57/3 should help as I evidenced last Sunday ; also the stock driveshaft has a lot of windup/rebound so I'm running a stiffer Octura
.150 which has far less of this.

[LuckyDuc]

Being a noob to FE boats I have a question... I've been flying helis for quite some time now. Has anyone incorporated a gyro and 'elevator' to assist with keeping the hull stable on the water? If so, how has it been successfully applied?

[Ub Hauled]

the response times are not fast enough... it has been thought of though.

Tony, I'll be there...

[AndyKunz]

Been tried, too, in the way back (10-15 years ago). I ran a boat with in at the 2000 FE Nats - water slams removed by canard after 1 lap.

Andy

[Capt. Crash]

Capt..

The buoys we use are made by Kershaw floatation in FL.

They are 12” foam spheres that one cuts in half. The great thing about these buoys is that they are firm but not hard. They lay flat on the water.. The boat does more glancing then hitting.. you have to hit them dead straight on to damage anything and truth is I have only ever broke a outrigger on one of these as they have a tendency to launch the boat…not grab it.. Any of this make since?

I have never seen this type of buoy at a FE race and I have always wondered why? Anybody help.. Maybe I am missing something?

Anywho…

ROCK ON

Grim

O yea.. one more thing.. the club paints the buoys.. the reason this is done as when struck it leaves a paint witness on the boat.. great info if needed for the CD.. Just make sure you clean it off before the next race..

Those sound pretty cool! :rockon2: But I don't think my tug could drag them out and set them without them flipping over on the way. I may try a smaller one to test. We are not allowed to use row boats or swim (even if you wanted to) in the park ponds...so we use a RC tug. See this thread for tug pics.

http://forums.offshoreelectrics.com/showthread.php?t=6350&page=2

[sailr]

Not sure, but I've heard that rounding the bottom front of the rudder will produce some lift?


Mike,

That's so the bottom of the rudder doesn't become a planing surface, right??


I should have noted above... I almost ALWAYS start out with my struts... all of my struts (monos and Hydros) flat... then tune from there... Otherwise, you can end up fighting a self-induced problem... Plus, it puts all of the thrust pointing in the direction it needs to be pointed!! ;)

[Grimracer]

oho.. nope-a-roni....

Now adding a radii to the lower leading edge..

Grim

[sailr]

Not sure I follow. See the attached drawing. Maybe I'm missing something here! :w00t:

9670



oho.. nope-a-roni....

Now adding a radii to the lower leading edge..

Grim

[Grimracer]

Sailr,

If you read post 21 it stated round or sharpen the bottom of the rudder... your sharpen is indeed my radii.

ROCK ON

Grim

[sailr]

Well alrighty then! Thanks!


Sailr,

If you read post 21 it stated round or sharpen the bottom of the rudder... your sharpen is indeed my radii.

ROCK ON

Grim

[6S HYDRO]

sailr,

if you read post 21 it stated round or sharpen the bottom of the rudder... Your sharpen is indeed my radii.

Rock on

grim

why cant this guy ever answer a question in understandable english?

[Grimracer]

Racers.. if you need to, read post 21 and then those that follow.. let me know if you understand what we were talking about.

but for 6S

Round the bottom of the rudder is used to "remove lift"... (the bottom of the rudder being the lowest flat part of the rudder).. We round this so the boat will not try to ride on that area of the hardware.

Sailr was asking and a tic confused (I can understand that) about what we were talking about so we made the clarification.. rounding the bottom leading edge.. "this adds lift". We call that adding radii to the rudder and this is used to control prop depth in the corners.

Anything there you need clarification on let me know.

Grim

[nate]

Turn fin!! all I have to say there.

[6S HYDRO]

Sailr took the time to sketch up a diagram all it would have took to answer this clearly for everyone is saying sketch "a" or sketch "b" is what im talking about. That easy

[Bill-SOCAL]

I'm more amused at a 6-month old thread being resurrected.

[Grimracer]

you and me both Bill.. you and me both!

ROCK ON SOCAL ROCK AND ROLLER!

Grim

[sailr]

:rofl:


why cant this guy ever answer a question in understandable english?

[Drag Boat Bob]

Racers.. if you need to, read post 21 and then those that follow.. let me know if you understand what we were talking about.

but for 6S

Round the bottom of the rudder is used to "remove lift"... (the bottom of the rudder being the lowest flat part of the rudder).. We round this so the boat will not try to ride on that area of the hardware.

Sailr was asking and a tic confused (I can understand that) about what we were talking about so we made the clarification.. rounding the bottom leading edge.. "this adds lift". We call that adding radii to the rudder and this is used to control prop depth in the corners.

Anything there you need clarification on let me know.

Grim

OK, you asked.

Please clarify why it is that every one of your answers needs an interpreter. I love my boat and this has nothing to do with that.

A simple yes or no (to the diagram by Sailr #1; #2) is the answer that almost every individual would recognize.

After 25 years in drag racing (OK, big boats... SORRY!) I still do not fully understand your answers. I would like to, but these answers are what I would expect from politicians.

If it has something to do with speed secrets (and I do understand that) then, just say that... or.. Just RTFQ and answer it!

It really is as simple as that.

Only then, will OLD posts die a natural death...

[6S HYDRO]

rock on drag boat bob

[longballlumber]

jeeze... :hornets_nest: If you guys only knew how much experience, how successful, how helpful, and NICE this guy you’re talking to is and has... I don't think you would treat him or anyone else like that.

Posting on technical discussions on a public forum like this is difficult. You can’t convey emotion, it’s tough to get your technical ideas into words, and you can’t talk to someone face to face.

Everyone take two steps back and take a deep breath. WE ALL are fighting the good fight!!!!

:hide:

[Capt. Crash]

I respect and appreciate the contributions to the hobby by all involved in this forum to include Grim....but I also understand exactly the frustration with the seemingly non or roundabout answers to some of the questions here....been there a few times.

The answers may seem clear to those that post them...but it is (apparently) not so clear to some of us less experienced readers. I'm occasional guilty of losing my patience for the same reason and I apologize for that....but guys please try to keep things a little more clear and simple for us new to the hobby...it would help keep us from being turned off to the hobby. :zip-up:

Crash

[Grimracer]

This is why its hard for me to post on these things..

RC boat racing.. playing.. testing.. … is a tuners game.

If you are willing to take the time to learn tuning and setup its a VERY VERY rewarding hobby..

Maybe im old school but just barfing out info cuz people might not be willing to learn through testing doesn’t do it for me.. maybe just me!…. Give me the simple way out.. just tell me.. is the feeling the boards give.. maybe that’s what they are for.. maybe that’s all they are good for..

Maybe that’s an argument for me to stay off of these silly things...

I have had some very profound experiences testing down at the pond.. most I will never forget... its just hard to get them on the boards. I dig this hobby so much but have not made any buds on the forums (not totally true.. Topfuel443 is a SUPER GUY and I a very good bud.. met him on the forums).. I guess its just me..

ROCK ON and good luck to all!!!!!!!

:tiphat:

Grim

[sailr]

I believe the hobby has had a resurgence because of the very helpful experienced boaters that share their experiences with the new guys. Everyone has to start somewhere. Those that are willing to share are truly the good guys of boating. When I started in the hobby 30 years ago, there was no such thing as these forums. You had to go to the races and try to learn what you could and hope you found at least one friendly guy.

Yes, it is often hard to get a point across because the new guy has no point of reference and unfortunately probably doesn't have a nearby club, etc. Any time you can add a photo or a drawing it helps!

Thanks Grim and to all the other good guys that help!!

[Drag Boat Bob]

This is why its hard for me to post on these things..

RC boat racing.. playing.. testing.. … is a tuners game.

If you are willing to take the time to learn tuning and setup its a VERY VERY rewarding hobby..

Maybe im old school but just barfing out info cuz people might not be willing to learn through testing doesn’t do it for me.. maybe just me!…. Give me the simple way out.. just tell me.. is the feeling the boards give.. maybe that’s what they are for.. maybe that’s all they are good for..

Maybe that’s an argument for me to stay off of these silly things...

I have had some very profound experiences testing down at the pond.. most I will never forget... its just hard to get them on the boards. I dig this hobby so much but have not made any buds on the forums (not totally true.. Topfuel443 is a SUPER GUY and I a very good bud.. met him on the forums).. I guess its just me..

ROCK ON and good luck to all!!!!!!!

:tiphat:

Grim

First straight answer I've seen so far, even though it's amidst some chaff. Too bad it took so long to hear (see) it.

This was NEVER about you (Grim) personally; just the manner in which you answer questions. Thank you, I am now clear.

There are so many here on the forum that have been eager to share information, even to the extent of multiple posts, that I may have mistakenly placed you in that category.

I believe you have designed a very fun boat and I thank you for that.

Bob

[properchopper]

Hey Bob, where in CA are you ? Near L.A. ?; we run at Legg Lake in S. El Monte;
lots of boats there & we need more FE. Know Steve Sharp? A good friend of mine.

Tony Heller
SoCal Fast Electrics

[Drag Boat Bob]

Hey Bob, where in CA are you ? Near L.A. ?; we run at Legg Lake in S. El Monte;
lots of boats there & we need more FE. Know Steve Sharp? A good friend of mine.

Tony Heller
SoCal Fast Electrics

Tony,
Will send a PM. I'm about 200+ miles north on the coast.

Not sure I am qualified to miss other boats in a heat quite yet (vision is not what it once was). I can try to stay on the outside however.
Bob

[properchopper]

.

Not sure I am qualified to miss other boats in a heat quite yet (vision is not what it once was). I can try to stay on the outside however.
Bob

I hear 'Ya Bro ! My vision sucks & my mental focus is worse ! One of the funniest
[ stupidest?] things I did at the Nat's last year was to space out at the start of a P-Mono heat & "forgot" to turn at the first buoy :doh:

[Drag Boat Bob]

Tony,
Will send a PM. I'm about 200+ miles north on the coast.

Not sure I am qualified to miss other boats in a heat quite yet (vision is not what it once was). I can try to stay on the outside however.
Bob

Mailbox full?

[properchopper]

Now cleaned out; re-post.:sorry:

[Shooter]

Here is an interesting patent from the 70's referring to a sponson vent. Apparently, pressure is able to vent out the sides of the sponsons with a small recess on each side. I've seen this on full size hulls at hydro races and people claim it works well to eliminate the sponson dance (side to side). Not sure how it will help us at scale speeds of 400mph or so??


Application Number:05/558151
Publication Date:07/06/1976 Filing Date:03/13/1975

SUMMARY OF THE INVENTION
This invention relates to a four-point tunnel hull for a boat.

It is common practice to so shape the bottoms of boats so that two longitudinally extending, downwardly projecting, laterally-spaced sponsons define therebetween a longitudinal channel extending from the bow to the stern of the boat and frequently are referred to as a "tunnel".

In such boats pressure builds up in the tunnel between the two sponsons, which can be released only at the stern of the boat. At high speeds, because of this pressure build-up, there is a tendency for the boat to ride up on the column of air pressure and then to fall off to either side, causing a "dig-in", "spin-out" or pass and flip backward.

In my novel hull a step is provided in each sponson intermediate the bow and stern. A portion of the pressure is relieved at these steps, so as to avoid the above dangers. The bottom of the front part of each sponson also lies at a sharper angle to the perpendicular than that of the rear part. The deep vee of the front part results in a smoother ride because of the improved entry into rough water. The flatter rear sponsons assist in carrying heavier loads under more stable conditions.

[Grimracer]

Step or Vent?

Not the same from what I know.. I read both in that post.

Grim

[sailr]

If you will look at most of the cat hulls, they are made that way.

[Steven Vaccaro]

This is why its hard for me to post on these things..

RC boat racing.. playing.. testing.. … is a tuners game.

If you are willing to take the time to learn tuning and setup its a VERY VERY rewarding hobby..

Maybe im old school but just barfing out info cuz people might not be willing to learn through testing doesn’t do it for me.. maybe just me!…. Give me the simple way out.. just tell me.. is the feeling the boards give.. maybe that’s what they are for.. maybe that’s all they are good for..

Maybe that’s an argument for me to stay off of these silly things...

I have had some very profound experiences testing down at the pond.. most I will never forget... its just hard to get them on the boards. I dig this hobby so much but have not made any buds on the forums (not totally true.. Topfuel443 is a SUPER GUY and I a very good bud.. met him on the forums).. I guess its just me..

ROCK ON and good luck to all!!!!!!!

:tiphat:

Grim

I think it has less to do with people looking for a lazy, easy answer and more to do with people not wanting to ruin a $20 rudder.

[Shooter]

I think it would be considered a vent. This is what it looks like, more or less.... It can be tuned to achieve the proper amount of bleed-off.

[dreamland s4]

Ride pads work! Thanks to detox!

[InspGadgt]

I was thinking about "the hop"...
Tony's UL did the same thing in the beginning,
looking back I believe it was a combination of factors...
first it was a little lose and started flying and then the first sponsons
would take off and land hard rebounding and throwing the hull to the other side
and so the hop started, violently like described earlier. The reason
it started bouncing side to side like that and get worst, is because the
turn fin would hit the water at an angle and push the hull
up to the other side again and then the vicious cycle would start
over and over again... if you can keep her nose down this dance
probably would not happen.

just my shot at it...

This is where I'm having an issue it seems...when watching my boat on the straights it looks like the turn fin is lifting the right side of the boat out of the water. Then when it hits a rough patch of water it starts the hop.

[InspGadgt]

It's not just depth, but also angle... I haven't run mine yet so I can't give you good answers... I've read to the effect that 1 1/6" of depth with a 3-degree downward angle works... I think that was Tony's setting (Properchopper)...

How are you adjusting angle? I can understand depth s with the strut but the stuffing tube goes all the way through the strut so the prop angle can't be adjusted independently from the stuffing tube...which is just depth.

[NativePaul]

This is where I'm having an issue it seems...when watching my boat on the straights it looks like the turn fin is lifting the right side of the boat out of the water. Then when it hits a rough patch of water it starts the hop.

That means the bend/curve in your turn fin is not parallel to your running attitude, you have to tilt the bottom of your turn fin back a little more, to get it parallel and stop it generating lift in a straight line.

[properchopper]

I did these mods and the UL-1 settled way down. (see vid below)

#1 : Reduced the AoA AND vented the air traps with some diversion strakes

160194

went to a squared-off turn fin : (picture prior to altering AoA)

160195

https://www.youtube.com/watch?v=yicE1_TfDDY

[properchopper]

How are you adjusting angle? I can understand depth s with the strut but the stuffing tube goes all the way through the strut so the prop angle can't be adjusted independently from the stuffing tube...which is just depth.

A simple way to allow strut angle adjustment is to [CAREFULLY] shorten stuffing tube so that it only extends roughly3/16" into the strut.Install lead teflon bushings for the propshaft.

[InspGadgt]

That means the bend/curve in your turn fin is not parallel to your running attitude, you have to tilt the bottom of your turn fin back a little more, to get it parallel and stop it generating lift in a straight line.

I've got it turned back as far as it will go...it is still lifting the boat.

However today I did try with a 3/8" air dam...it was rougher out there but my boat was still more stable than last time I ran it.

[InspGadgt]

I did these mods and the UL-1 settled way down. (see vid below)

#1 : Reduced the AoA AND vented the air traps with some diversion strakes

160194

went to a squared-off turn fin : (picture prior to altering AoA)

160195

https://www.youtube.com/watch?v=yicE1_TfDDY

That's what I was thinking on doing with my turn fin...I hadn't thought of a vented air dam. The flat air damn I tried today made it really difficult to get the boat moving so I was thinking about an angled air damn but I like your idea too. How tall did you make your air damn?

[InspGadgt]

Has anyone tried this: https://www.offshoreelectrics.com/proddetail.php?prod=hug-ul1-foil Any feedback on it?

[InspGadgt]

A simple way to allow strut angle adjustment is to [CAREFULLY] shorten stuffing tube so that it only extends roughly3/16" into the strut.Install lead teflon bushings for the propshaft.

Looking at the strut replacement part listed: https://www.offshoreelectrics.com/proddetail.php?prod=dh-aqub6950 It looks like the strut should already have a bushing and the stuffing tube should be shorter.

As much as I've enjoyed this little boat and how cool it looks...I'm getting a bit frustrated with not only all I have to go through to get it to keep up with a UL-19 on 4s...but also with the quality control issues I'm running into. First the boat starts to crack along the seam on the inside left sponson. Then I notice the motor does not line up properly with the stuffing tube. Had they made the motor mount adjustable that would have been an easy fix to compensate for any manufacturing misalignments. The rudder has no break away...and my motor strut is not adjustable in angle, only in depth. The motor wires were routed poorly and interfere with battery installation. I had to re-route the wires over the top of the motor and the wire lengths are just barely long enough to work. And the ESC has to be re-programmed every time you plug in the battery...just really poor choice in electronics there. I'd would have rather this boat be offered in an ARR format so I could use my own electronics. Some of the choices made in manufacturing this boat make sense if it were a one off build...but in a mass produced environment where mistakes occur regularly a little bit of added adjustability in the design would have compensated for the inaccuracies. I don't see how they can claim the boat is capable of 65+mph when it starts losing stability around 43mph.


Don't get me wrong...I don't think this is a bad boat...I really like it a lot. I just thing things could have been done better with a little more care and foresight.

[properchopper]

There are auto mechanics schools where the students are given a poorly running engine and their assignment is to find out what's wrong and fix it. They become better mechanics after this learning experience. Sounds like your experience with the UL-1 parallels this (of course only if you choose this way of looking at it ). I know that my personal experiences in boat building follows this closely ; each boat I build teaches me something so the next one comes out even better. The UL-1 is about a decade old and when it was introduced it was one of the best values for a nicely performing rtr. Needless to say the "Igottagofaster" bug bit and the hull was soon pushed past its design limits - but even so it is a decent value (plus remember that to hit a entry level price point the build labor costs are kept down by using nine year old laborers who make cukoo clocks on their morning shifts). To elaborate, one of my bespoke FE30's will set you back double what a fresh rtr UL-1 or Proboat version costs but won't need ANY fiddling for its lifetime - e.g. my personal FE30, the VERY FIRST production model @10 years young) is now current 2018 SCSTA high points holder and the ONLY thing that gets done to it year after year is to grease the flex after every race, put a drop of oil front & rear on the motor bearings, and once a year replace the strut bushings.
Hang in there - it gets better:wink:

[InspGadgt]

Thanks...I know it will get better. I've been a bit frustrated is all.

So back to your earlier post where you put the air damn on...the wood under the sponsons...to me it looks like you did this to decrease the angle of the sponsons and to eliminate the step in the sponsons. Is that what you were intending or am I reading it wrong?

[properchopper]

Thanks...I know it will get better. I've been a bit frustrated is all.

So back to your earlier post where you put the air damn on...the wood under the sponsons...to me it looks like you did this to decrease the angle of the sponsons and to eliminate the step in the sponsons. Is that what you were intending or am I reading it wrong?

you did this to decrease the angle of the sponsons ----- yes


to eliminate the step in the sponsons. ----- NO

[Fluid]

One of the initial “problems” with this hull was not a problem with the hull at all. Prior to it’s introduction a highly experienced racer took a pre-production hull and ran it at a SAW event that both Tony and I attended. He ran over 67 mph through the traps and the only mod was screwing on a huge prop. Since then folks have been obsessed with making it go faster than it was designed to go. Tuning secrets like CG and strut adjustment, along with limited run time, were ignored and there were many folks who were disappointed with the boat - through no fault of its own. If the UL-1 is to be run well past it’s design speed then hull mods will likely be necessary.


.

[NativePaul]

I've got it turned back as far as it will go...it is still lifting the boat.

So make it go back further, the bend/curve acts like a hydrofoil and if the front of the bend is higher than the back it will give lift in a straight line, and if the back is higher than the front it will give downforce in a straight line.

The only other alternative is that it is not going in a straight line, but turning left, which will also make it ride up the turn fin. Is your rudder set straight? Is the strut straight from left to right? If not you could be crabbing sideways whilst tracking a straight course.

[properchopper]

From the Vault (referring to the day Jay mentioned) :

160205

:thumbup1:

[InspGadgt]

So make it go back further, the bend/curve acts like a hydrofoil and if the front of the bend is higher than the back it will give lift in a straight line, and if the back is higher than the front it will give downforce in a straight line.

The only other alternative is that it is not going in a straight line, but turning left, which will also make it ride up the turn fin. Is your rudder set straight? Is the strut straight from left to right? If not you could be crabbing sideways whilst tracking a straight course.

Boat is trimmed to run straight so the rudder should be set straight. Strut looks fine other than it is missing the bushing that it is supposed to have. The turn fin is actually angled down slightly...back is higher than front on the big bend line.

[InspGadgt]

you did this to decrease the angle of the sponsons ----- yes


to eliminate the step in the sponsons. ----- NO





Interesting...so our running area is not as smooth as yours is in the video. Will a lower sponson angle help in rougher water?

[properchopper]

Interesting...so our running area is not as smooth as yours is in the video. Will a lower sponson angle help in rougher water?

most likely. If it tames down the tap dancing in smooth water it should have a similar effect in "rougher water". I don't run hydros in rough water fwiw.

[InspGadgt]

most likely. If it tames down the tap dancing in smooth water it should have a similar effect in "rougher water". I don't run hydros in rough water fwiw.

I wouldn't if I had a choice :) We only have 1 fresh water source on the island and that's too small for these speeds. The alternatives are both brackish water and it would probably be more classified as a river than a lake.

I ordered the Hug airfoil from OSE so I'll be giving that a try first. After that I'll be working on an air dam similar to you and possibly the sponsons as well.

[InspGadgt]

So here's my strut with stuffing tube...as you can see I have no prop bushing. The stuffing tube just goes all the way through my strut. If I had a proper strut I could use some prop angle adjustment to help calm down the hopping. I'm hoping customer service will replace it with a proper strut but with them in the middle of a transition to Horizon, things have been moving a little slow.

[MADRCER]

So here's my strut with stuffing tube...as you can see I have no prop bushing. The stuffing tube just goes all the way through my strut. If I had a proper strut I could use some prop angle adjustment to help calm down the hopping. I'm hoping customer service will replace it with a proper strut but with them in the middle of a transition to Horizon, things have been moving a little slow.
You can see the bushing in the picture. It's in the stuffing tube....Nothing wrong with that. Pull it out, free it up so it floats inside and trim the tube a little then let her rip. Order another one if you have the old style because the new style has larger holes for better lubrication.
https://www.offshoreelectrics.com/proddetail.php?prod=dh-aqub8003

[InspGadgt]

I'm not sure that's the bushing...my understanding was the bushing was supposed to come up to but not connect with the stuffing tube. If that is it...it's pretty stuck on...i don't think i'll be able to free it up. But when I looked at it it just looked like 1 piece with a ring grooved in.

[MADRCER]

I'm not sure that's the bushing...my understanding was the bushing was supposed to come up to but not connect with the stuffing tube. If that is it...it's pretty stuck on...i don't think i'll be able to free it up. But when I looked at it it just looked like 1 piece with a ring grooved in.

I'm sure it's stuck because most are just crammed in there. It'll come out just work with it. Throw it away and get the new version.

[InspGadgt]

The new version?

[InspGadgt]

I don't know...it is really tight and the thickness of the tube wall is the same as the other end. If it is...it is really stuck in there...I don't think it is coming out.

[properchopper]

So here's my strut with stuffing tube...as you can see I have no prop bushing. The stuffing tube just goes all the way through my strut. If I had a proper strut I could use some prop angle adjustment to help calm down the hopping. I'm hoping customer service will replace it with a proper strut but with them in the middle of a transition to Horizon, things have been moving a little slow.

Mr. InspGadgt,

This may not sit well but because you need some truth therapy I'll give the best of my knowledge and experience to get you some actual workable solutions -

#1 - You DO have a prop bushing. It's inserted into the end of your stuffing tube. This is standard operating procedure for about 80% or more of all rc boats - particularly those in the IC realm. The alternative is to replace the brass sleeve bushing with lead teflon bushings. They need more frequent replacement so the RtR boats often don't come with them.

#2 - it seems (from your picture) that your stuffing tube is pinched at the point it would enter the strut. This may be capturing your brass bushing making it hard to remove. Get it OUT somehow. If it doesn't turn freely chuck up the back end in a drill, smear some toothpaste (for lapping compound) on it and pull the trigger. This should soon allow it to spin freely. Clean off toothpaste when done.

#3 - You DO have a proper strut - Asking Horizon to put on a "proper strut" to a model being sold successfully "as is" for the last ten years or so (thousands sold) may not get you the response you're looking for.......

#4 - A stuffing tube extending all the way through the strut is a very common way of how it's been done for eons. In fact you CAN adjust strut angle with a little pressure on the strut - it'll bend/flex the slight amount you may need for a minor adjustment.

BUT

#5 - Regardless of how you adjust height/ angle (a tad too much height/angle and you'll have the rear hopping up and down - (I know this with knowingness.) and you WON'T cure the front sponson "hospital hop". For more than stock performance ONLY reducing the sponson AoA will get this done. TrustMe ! Tacking on aero goodies might sound good but...

Realize that this is a hobby-grade model designed to perform "as delivered" and runs beautifully in smooth water with the supplied prop. Once you go for more performance or run it in bouncy water mods need to be done and expectations carefully thought out.

Enjoy :thumbup1:

Tony

[InspGadgt]

Ok thanks. I've been trying some penetrating oil to try and get it to loosen up so far but no luck. It is so tight if I chuck it in a drill I think I would damage the stuffing tube too. I guess I'll try heating it next and see if I can get it to free up.

[properchopper]

Lapping the brass bushing with a drill comes AFTER it's removed and can be inserted reasonably easy. To get yours out if it's that tight you might heat the stuffing tube (put a wet rag around the tube where it enters the hull to prevent heat transfer damage) and grab the end in vice grips. You might need to sacrifice the end but a replacement brass bushing doesn't cost much.

OR much easier and will allow less stressful strut angle adjustment :

Cut stuffing tube so that only 1/4" or so enters the strut and press in one at the rear and one right after where the stuffing tube ends.

https://www.offshoreelectrics.com/proddetail.php?prod=oct-oc6ltsb

[InspGadgt]

#3 - You DO have a proper strut - Asking Horizon to put on a "proper strut" to a model being sold successfully "as is" for the last ten years or so (thousands sold) may not get you the response you're looking for.......

Mainly I'm just asking for the one that was supposed to be sold with the boat as I mistakenly thought I didn't already have it.


#5 - Regardless of how you adjust height/ angle (a tad too much height/angle and you'll have the rear hopping up and down - (I know this with knowingness.) and you WON'T cure the front sponson "hospital hop". For more than stock performance ONLY reducing the sponson AoA will get this done. TrustMe ! Tacking on aero goodies might sound good but...

I'll definitely try the AoA and the air damn mod you have pictured. The aero mod I got from OSE is only a part of the testing to see what works. After more than 20 years of racing on-road RC I know not to do to many changes at once or you can't tell what is really working and what did not.


Lapping the brass bushing with a drill comes AFTER it's removed and can be inserted reasonably easy. To get yours out if it's that tight you might heat the stuffing tube (put a wet rag around the tube where it enters the hull to prevent heat transfer damage) and grab the end in vice grips. You might need to sacrifice the end but a replacement brass bushing doesn't cost much.

OR much easier and will allow less stressful strut angle adjustment :

Cut stuffing tube so that only 1/4" or so enters the strut and press in one at the rear and one right after where the stuffing tube ends.

https://www.offshoreelectrics.com/proddetail.php?prod=oct-oc6ltsb

That looks like a much easier fix...is that a common mod done on this boat?

[InspGadgt]

Ok well heating didn't break the bushing free and I got a nice burn on my thumb while trying. So I ordered 2 replacement bushings and 2 of the bushings that was linked earlier. I'm going to have to crush the installed bushing to get it out...if it comes out after that I'll try the stock replacement bushings. If it damages the tube I'll cut it and use the other bushings. Thanks for all the help!

[InspGadgt]

I got the bushing out! I crushed the end with pliers so that it would start to pull away from the stuffing tube and it pulled right out. The end of the stuffing tube was pretty ratty so I figure that's what was locking the bushing in place. I sanded the stuffing tube end with an emory board then removed any flashing and restored the roundness with a body reamer tool. Now the new one just slides in easily except for where the flange meets the strut. The bushing is a really tight fit in the strut so I'm wondering how far it should go into the strut. I've pushed it in by hand as far as it will go but that is only like .5mm. I'm not sure if I should use a hammer and lightly tap it in deeper or sand the flange lightly so it fits more easily into the strut.

[InspGadgt]

I did these mods and the UL-1 settled way down. (see vid below)

#1 : Reduced the AoA AND vented the air traps with some diversion strakes

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went to a squared-off turn fin : (picture prior to altering AoA)

160195

https://www.youtube.com/watch?v=yicE1_TfDDY

So I'm getting closer to starting hull modifications and wanted to run something by you. In your air dam pic you cut a hole for the air to vent out of the side and it looks like it didn't compromise the integrity of the hull...I was thinking maybe it would be a good idea to remove the whole webbing piece...maybe an air dam might not be needed then as more air will be able to escape out the sides. If so do you think it will need some fiberglass reinforcement?

[InspGadgt]

So after trying a lot of different things like air dams and that lexan aero piece OSE sells and even sharpening and balancing the prop...none of them helped to stop the chine walk. It seems the consensus is this is a result of the boat trapping too much air under it so I finally committed to some hull modification to try and alleviate the issue. I cut off as much of the side webbing as I dared to allow the air to more easily escape out of the sides of the boat. I cut it down to where the side of the boat angles away. I have to wait for parts to arrive though before I can test it. My motor collet nut split yesterday and won't hold the shaft anymore.

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[InspGadgt]

Didn't get a chance to test this past weekend due to a hurricane almost hitting us. Hopefully I will be able to this coming weekend.

[InspGadgt]

Well helping the air to escape did not solve the problem. I just can't seem to get this boat to perform :(

[properchopper]

Here's a thought ( you've read this from an earlier post in this thread) :

" #5 - Regardless of how you adjust height/ angle (a tad too much height/angle and you'll have the rear hopping up and down - (I know this with knowingness.) and you WON'T cure the front sponson "hospital hop". For more than stock performance ONLY reducing the sponson AoA will get this done. TrustMe ! Tacking on aero goodies might sound good but....."

The rest is just Kabuki Theater..................

[CraigP]

ProperChopper is right in my opinion. The AoA is everything to getting a clean setup. But it’s a lot of work to change it... I’m not going to discuss specific angles, there’s more to it that that. But getting up to speed on what makes great hydro sponsons is worth looking into... I will say this, 3.85 degrees is TOO MUCH, lol!

[InspGadgt]

Here's a thought ( you've read this from an earlier post in this thread) :

" #5 - Regardless of how you adjust height/ angle (a tad too much height/angle and you'll have the rear hopping up and down - (I know this with knowingness.) and you WON'T cure the front sponson "hospital hop". For more than stock performance ONLY reducing the sponson AoA will get this done. TrustMe ! Tacking on aero goodies might sound good but....."

The rest is just Kabuki Theater..................

Referring back to the modification on your boat where you added wood pads and sanded them to have less angle than the stock sponson? I've been planning to get around to that mod soon. I'm just doing one at a time and testing results. It's a long and frustrating process.

[InspGadgt]

ProperChopper is right in my opinion. The AoA is everything to getting a clean setup. But it’s a lot of work to change it... I’m not going to discuss specific angles, there’s more to it that that. But getting up to speed on what makes great hydro sponsons is worth looking into... I will say this, 3.85 degrees is TOO MUCH, lol!

Is there a good website resource to learn about hydro sponson design?

[InspGadgt]

I did these mods and the UL-1 settled way down. (see vid below)

#1 : Reduced the AoA AND vented the air traps with some diversion strakes

160194

went to a squared-off turn fin : (picture prior to altering AoA)

160195

https://www.youtube.com/watch?v=yicE1_TfDDY

So I started working on reducing the AoA last night. I sanded the bottom of the sponsons to get maximum adhesion for the new pads I'll be gluing on and I found that the ride pads on the sponsons stock are no where near flat. They are really far off.

[InspGadgt]

Well that didn't work. Still had a lot of chine hop. Unfortunately I didn't seal the wood good enough either so by the end of the testing day the wood blistered off of the sponsons. Time to try something else.

[InspGadgt]

I finally solved the problem! I went back to the idea of a front wing and built one with a much larger spoiler on it than the last wing I tried. Took it out and was able to open it all the way up without it going crazy. Yes there still was some chine walk but not enough to flip the boat at full tilt.
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