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View Full Version : Miss Geico dialed in- strut modification



BHChieftain
05-06-2013, 12:46 AM
Hi,
My son has been racing his Miss Geico (V2) in the p-limited offshore class, and we have it dialed in on stock setup with x642 prop. Batteries are just behind the front end of the motor (non-shaft side). Per the tips on the forum, I ground a wider slot in the strut, allowing a bit of negative angle. I have the strut up pretty high-- with the sponsons on the table the shaft does not touch the table-- close-- probably less than 1/8 above it (in the picture it looks like more, but that is just due to the camera angle).

In race conditions (ie, some race-induced chop in the water), the boat rides perfect, no bounce. In glass water, we get a slow bounce. I have not blueprinted the sponsons, and probably won't bother as the boat is doing great in race conditions.

Been too busy coaching my son through the races to get a video, but will try to get one next time.

Chief

tlandauer
05-06-2013, 12:52 AM
That is just awesome! :rockon2:

hydro_pyro
05-06-2013, 07:00 AM
(edited to reflect edit above) ;)

Looks good, I will probably do the same with mine.

BHChieftain
05-06-2013, 08:39 AM
Whoops, I meant negative-- to push the nose down just a tad. I'll edit that.

Chief

PvtSpoon
05-06-2013, 09:09 AM
Do you have a link for the rules for running p-limited offshore class, as I'm trying to kick start FE racing at the club I'm part of


Thanks

BHChieftain
05-07-2013, 09:15 AM
Here you go

http://www.namba.com/content/library/rules/namba_rulebook.pdf

Chief

TheShaughnessy
05-07-2013, 09:54 AM
Now just off set that rudder a tad. Won't scrub so much speed in the corners, better top end down the back strait ( for the offset course) and it should still turn to the left just fine for the one left hander.

macace123
05-09-2013, 11:50 PM
Can you take more pics of the top of the strut to see the level

BHChieftain
05-10-2013, 12:37 AM
Here you go. You can see in the second picture the top of the strut bracket and the angle I get with the modification.
Chief

JimClark
05-10-2013, 02:41 AM
Thanks James just what I need for my boat I am working on.

bdp1174
05-10-2013, 02:57 AM
Awesome info and pics I will use this information to help me get my blackjack 29 dialed in.

maxmekker
05-10-2013, 11:40 AM
I wish I could find my 'old' stock strutt so I could try this out. I got the kintec strutt pritty fast after getting the geico , but I did no good to the bounch , so I feel. I think I have been into all settings and battery placements to get it to run smoother.
Anyway, great info, and hope to see a video soon :-)

macace123
05-10-2013, 12:24 PM
wow thanks Cheif for the pics much help looks great.:beerchug:

Speedracer128
05-11-2013, 12:26 PM
I'm kinda new to rc boating so excuse me for not understanding exactly what you did to the strut so that it can have some negative angle to keep the nose in the water better. When you are talking about grinding the strut some does that mean you take some off the front of the strut(the side closer to the boat? Or drilling the inside of the strut so it has more play?

I have a MG and with my stock set up I had everything pretty good. I put a 180 esc and a nemesis 4080. So run it with an x642 and an x646 and I'm still trying to dial it to run more stable. She is really fast IMO. ATM I'm running with smaller prop till I learn to control her better

BHChieftain
05-11-2013, 10:15 PM
I'm kinda new to rc boating so excuse me for not understanding exactly what you did to the strut so that it can have some negative angle to keep the nose in the water better. When you are talking about grinding the strut some does that mean you take some off the front of the strut(the side closer to the boat? Or drilling the inside of the strut so it has more play?

I have a MG and with my stock set up I had everything pretty good. I put a 180 esc and a nemesis 4080. So run it with an x642 and an x646 and I'm still trying to dial it to run more stable. She is really fast IMO. ATM I'm running with smaller prop till I learn to control her better

If you look at the 3rd picture in the first post-- I took a dremel tool and enlarged the inside "slot"-- rounded out a bit so that when I move the strut up I can get some play to set the angle.

Chief

Speedracer128
05-12-2013, 12:04 PM
Ok thanks. Ill check when I get home. I'm on my phone now so I can't see the difference but I think I get what you are saying

hydro_pyro
05-13-2013, 04:31 PM
I did this modification to my Blackjack 29 today. Night-and-day difference! I've got a little bit of mid-range porpoise, but then it flattens out and hauls ass with no bounce.

I usually run 6s by means of three 2s packs in series, with the third pack up front.

Speedracer128
05-13-2013, 04:41 PM
Good mod. thanks for sharing the info. seems like it gives much more room to adjust the strut

jeffrey1
05-14-2013, 11:24 AM
looks good.

AlanD
05-14-2013, 04:03 PM
https://www.youtube.com/watch?v=_Uln02dfrSs

This is my run from Sunday. Still a little bounce at high speed. OSE has a new upgrade strut which should be released this week. I'll be ordering that soon with the M440.

hydro_pyro
05-14-2013, 06:20 PM
That sounds like a solid 35000+ RPM. On the stock prop, you should be running in the lower 60's there. Very nice.

Try raising the strut a bit more vertically, while keeping the same down angle. You might need to bend the stuffing tube a bit to keep the strut aligned. This should give you even more stern lift to keep the back end high and loose to reduce porpoise.

AlanD
05-14-2013, 10:08 PM
Thanks hydro. I did use some of your pointers on other threads to get it where it is now.

The prop is about 4mm from the bracket with about 2 degrees downward pitch and I did drill out the strut as shown above so I could get the negative angle and still align the ferrel on the end of the shaft. Make note that strut steel is bitchin' hard!! I used a stone grinding bit on my Dremel to do it.

I have some pics of my current setup in this thread if you want to critique my setup.
http://forums.offshoreelectrics.com/showthread.php?40735-Leopard-4082-motor-mount-photos

hydro_pyro
05-15-2013, 12:02 PM
I'm pretty sure that's all high-quality aluminum, but I could be wrong. Aluminum tends to wrap itself around the Dremel bit, clog up the abrasive surface, and sort of "burn" away while you're grinding... This can make it more difficult than some other materials.

I used a spiral-fluted metal cutter bit, and finished with a small stone bit.

ozzie-crawl
05-15-2013, 07:17 PM
I know there different hulls but the last cat i ran a couple of years ago was a Mean Machine. They do seem similar in being not much depth in the tunnel but fairly wide.
The strut on that was around 1/4 of a inch up of the rear sponsons from memory.
Wondering if a strut with a short extension on the rear would allow prop clearance for moving it up more.
I think in theory it would stlightly lenghten the boat makeing it a little more stable.
Just a thought as mine has not seen water yet. You can also see in some videos were the prop wash is hitting the strut bracket this from memory would also cause some lift,if the prop was back a little it should stop this as well.

hydro_pyro
05-18-2013, 11:05 PM
Simply moving the batteries far forward as others have suggested does not correct the problem. It just makes the front of the boat "plow" while the back end "digs in." Raising and angling the strut downward gives the boat the stern lift it needs, and the packs don't need to be moved as far forward, because the hull doesn't tend to trap air when it runs high and dry.

I ran mine again today on 4s and again on 6s. No bouncing. This simple modification is the ticket for this hull.

tlandauer
05-19-2013, 03:24 AM
Simply moving the batteries far forward as others have suggested does not correct the problem. It just makes the front of the boat "plow" while the back end "digs in." Raising and angling the strut downward gives the boat the stern lift it needs, and the packs don't need to be moved as far forward, because the hull doesn't tend to trap air when it runs high and dry.
I ran mine again today on 4s and again on 6s. No bouncing. This simple modification is the ticket for this hull.

Well said! This should be a mandatory "Read before moving COG forward" notice!!!
BTW, the Proboat manual doesn't tell anything, on mine ( MG V1) they even got the prop thrust angle backwards, there is absolutely no excuse for that kind of misinformation.

ozzie-crawl
05-19-2013, 04:20 AM
Had my first run today. Really happy for its first time out.
Will post a video up shortly and hopefully you guys can give me a bit of advice on setup.
Strut is up about 2mm from bottom of sponsons when hull is flat on the bench. Prop angled down a little. Its the most i could get with out mods the the bracket/strut. COG at 30%

hydro_pyro
05-19-2013, 09:22 AM
Get out your Dremel and do the mod. You won't be sorry.

hydro_pyro
05-19-2013, 09:28 AM
Here's mine... strut hole egged out, raised, angled, and aligned. No bouncing.

http://i1247.photobucket.com/albums/gg629/hydropyropyropyro/D897E138-AEC6-42EC-AD3E-E45DCC4F0EA0-28333-0000330DAD47EAA7.jpg

ozzie-crawl
05-19-2013, 09:46 AM
Thanks for the pic. Mines not that high, will break out the dremel tomorrow and give it another try.

hydro_pyro
05-19-2013, 05:10 PM
The higher you go, the more stern-lifting effect you get, at the slight expense of holeshot punch.

Speedracer128
05-19-2013, 06:25 PM
@ hydro
If the higher the strut is the more stern lifting effect happens does that push the bow down as that happens?

ozzie-crawl
05-19-2013, 07:10 PM
Been awhile since i played with boats so could be wrong but when raising the strut it should push the stern into the water further creating more stability.
By adding angle to the prop lowers (prop angled down) or lifts (prop angled up) the bow.

hydro_pyro
05-19-2013, 10:42 PM
The propeller produces a cone-shaped thrust profile. When less of the thrust cone is below the surface, it results in a stern lifting effect. This allows the COG to be moved back. Angling the strut downward further amplifies the stern lift.

Angling the strut neutral or "up", or running the prop deeper does lift the bow, but it keeps the stern glued to the water, which causes the tunnel to pack too much air. When the air pushes its way to the back, the stern pops up and farts the air bubble out the back, and the bow drops. Then it starts all over again. Hop, hop, hop. All the while, it's itching to blow over.

By un-wetting the stern, the boat can ride smooth and fast without the hopping. The COG keeps the bow up, and lift provided by the prop keeps the stern up. Hydrodynamic drag is reduced. More speed, less hop.

ozzie-crawl
05-20-2013, 12:31 AM
Did the strut mod with batts at 30%. Not lifting and dropping the front any more. Boat stays flatter and more planted but does bounce a little bit. Very stable tho and does not look like blowing over.
Tried the batts forward a little and was a about the same so tried moveing them back further and had a blow over.
This was on flat water. From my testing the day before a bit of chop will make in run spot on.

AlanD
05-26-2013, 08:38 PM
hydro_pyro and tlandauer, can you guys post photos of the interior layout of your boats with battery packs installed? Pyro, I'm wondering if your use of a third battery pack upfront is keeping your bow more stable, whereas many of us are just using 2 packs, creating the need for a slightly different cog. Without going too far down the polar moment of inertia road, I'm curious if you have a different distribution of weight to us "2 packers." :)

Speedracer128
05-26-2013, 10:27 PM
A third pack will def change the balance of the boat but I'd like to know how much a dif it makes also

Once I upgraded my motor and esc my MG blew over constantly, even with my strut angled down and packs forward. On one of the blow overs I had a seem split so I reinforced it with a heavy coat of resin with fiberglass strands in it and that totally changed the ride of the boat because of the extra weight. I know it slowed the boat down a bit but I like the extra weight up front. How it is now, even at high speeds she's not trying to blow over and the other great things is that when I hit waves and she goes airborne with the extra weight the boat stays level. So I'm much happier with how she rides now

ozzie-crawl
05-26-2013, 10:31 PM
Not one of those you asked but Given mine a few short runs the last couple of days and have eliminated the bounce altogethor in slight chop. Useing the strut mod posted here and batteries are 35mm from front of battery tray. Cog is 205mm from rear of sponsons or around 29%.
Been fairly windy so not certain how it will run on smooth water.
Running a pb1500kv motor on 6s (2x3s 4000mah) with a detounged x642. Have not bothered temping any thing as motor and esc have hardly any warmth after a 4 min run.

tlandauer
05-27-2013, 01:43 AM
Did the strut mod with batts at 30%. Not lifting and dropping the front any more. Boat stays flatter and more planted but does bounce a little bit. Very stable tho and does not look like blowing over.
Tried the batts forward a little and was a about the same so tried moveing them back further and had a blow over.
This was on flat water. From my testing the day before a bit of chop will make in run spot on.


hydro_pyro and tlandauer, can you guys post photos of the interior layout of your boats with battery packs installed? Pyro, I'm wondering if your use of a third battery pack upfront is keeping your bow more stable, whereas many of us are just using 2 packs, creating the need for a slightly different cog. Without going too far down the polar moment of inertia road, I'm curious if you have a different distribution of weight to us "2 packers." :)

@ AlanD, Just a quick reply before I have time to take pictures: I don't think a third pack in front of the motor is the answer. When the boat is dialed in with the COG at where it's supposed to be, there should not be a need for extra weight forward of the motor.

Speedracer128
05-27-2013, 01:54 AM
Ozzie
What kind of speeds are you getting with that setup?

tlandauer
05-27-2013, 03:04 AM
hydro_pyro and tlandauer, can you guys post photos of the interior layout of your boats with battery packs installed? Pyro, I'm wondering if your use of a third battery pack upfront is keeping your bow more stable, whereas many of us are just using 2 packs, creating the need for a slightly different cog. Without going too far down the polar moment of inertia road, I'm curious if you have a different distribution of weight to us "2 packers." :)
@ AlanD,
99588 99589
I am ashamed to admit that it's been a long time since I ran my MG, I don't remember what was the exact spot.:frusty: But you can see the range od adjustment on my battery tray is about 2.5". In order to get the so-called 30% COG , the batteries have to go to the rear like photo No.2.
I never made a science out of it, I will see how the water is and put them some where in between, drive the boat for 30 second and bring her in, adjust the batteries and go out again. What I found out was that with the sponsons trued and the strut up, the boat doesn't bounce and the forward COG is really to prevent unnecessary blow over should the wind and chop conditions are not favorable.

ozzie-crawl
05-27-2013, 05:21 AM
Ozzie
What kind of speeds are you getting with that setup?

I would not like to guess and have not gps,ed it as yet. just got a new data logger to run bullets on (other has deans) but still need to order gps for it.
Here is a short video of the last few laps i ran this afternoon. http://youtu.be/GzE2-IP44M0
Video is a bit poor as it was of my phone and had the res turned down and zoom on.
The water had a decent amount of chop that the hull seems to really like but there was a decent wind as well. running into the wind (away from camera) i was taking it easy and the getting wot coming back but you here me get of the throttle a few times.
Had a short run on other side of lake were it was much smoother and it has a slight bounce but runs nose high and airs right out.

kwiktsi
05-27-2013, 07:52 AM
Not one of those you asked but Given mine a few short runs the last couple of days and have eliminated the bounce altogethor in slight chop. Useing the strut mod posted here and batteries are 35mm from front of battery tray. Cog is 205mm from rear of sponsons or around 29%.
Been fairly windy so not certain how it will run on smooth water.
Running a pb1500kv motor on 6s (2x3s 4000mah) with a detounged x642. Have not bothered temping any thing as motor and esc have hardly any warmth after a 4 min run.

Hey Ozzie- what ESC are you running in yours?

ozzie-crawl
05-27-2013, 08:01 AM
Hey Ozzie- what ESC are you running in yours?

Still just the stock one. It is just getting a bit of warmth in it after a 3-4 minutes of running. All plugs are 5.5mm bullets.
Will try get a some data logging done next weekend see what amps it is pulling.

AlanD
05-27-2013, 08:21 AM
@tlandauer - thanks for the pics. My batteries are flipped 180 degrees from yours so our wires are in the same position as in your second photo. Yet my cog is right on the stuffing tube bulkhead which is about 30%. Its just the little bit of bouncing at WOT which I'm working out. I'll try your positioning later today and report back.

Speedracer128
05-27-2013, 10:19 AM
It was choppy and it was still running good. Is that a stock blackjack on 6s with the strut angled down with this mod?

I need a GPS too

hydro_pyro
05-27-2013, 11:47 AM
Remember to carefully bend the stuffing tube and re-shape it so it's aligned with the sleeve in the strut. Add more bend where the tube exits the hull, and straighten out some of the bend as it approaches the strut.

kwiktsi
05-27-2013, 02:45 PM
Still just the stock one. It is just getting a bit of warmth in it after a 3-4 minutes of running. All plugs are 5.5mm bullets.
Will try get a some data logging done next weekend see what amps it is pulling.

Wow, can't believe the stocker is holding up on 6S. How long have you been running it like this?

ozzie-crawl
05-27-2013, 06:30 PM
It was choppy and it was still running good. Is that a stock blackjack on 6s with the strut angled down with this mod?

I need a GPS too

Still stock except for motor and prop. Only thing else was the strut mod in this thread. Have not blue printed sponsons yet.

ozzie-crawl
05-27-2013, 06:36 PM
Wow, can't believe the stocker is holding up on 6S. How long have you been running it like this?

Only had the boat a couple of weeks so its done about 1 hours worth of running. After a 3-4 minute run every thing is only just warm.
I reckon i could do a 7-8 min run with out any thing getting hot.

BHChieftain
05-27-2013, 06:56 PM
Remember to carefully bend the stuffing tube and re-shape it so it's aligned with the sleeve in the strut. Add more bend where the tube exits the hull, and straighten out some of the bend as it approaches the strut.


+1 !!! else you'll see water shooting up the stuffing tube.
Chief

Speedracer128
05-27-2013, 07:05 PM
What does changing the angle of the stuffing tube do to handling or performance?

I run my MG on 6s with a 4082 and a 642 or 646 prop. I haven't made any adjustments to my stuffing so I'm wondering if I'm missing something

AlanD
05-27-2013, 07:44 PM
Ok, so I moved the battery packs to your position. Usual strut down angle. Slight breeze, pretty flat water. The boat ran so nose high at half throttle it was at risk of blowing over and still had a lot of bouncing. I pulled it out after 2 minutes and respositioned the batteries to their "usual" place and ran again. Now I'm back to really flat running with only a little bounce at WOT.

My deduction is that my motor must be heavy enough to warrant the cog being between the motor face plate and stuffing tube bulkhead. The lesson learned is that you have to do whats right for your particular setup to get what you want out of it. Here's my setup for what its worth.
99612996139961499615

hydro_pyro
05-27-2013, 08:02 PM
To answer speedracer's question...

Notice in the 2nd photo above this post, how the strut shown is angled down, but the strut is not correctly aligned with the stuffing tube. You can see where the angle changes at the joint-- the tube turns upward, but then the strut angles downward. It doesn't affect handling, but correcting the mis-alignment will reduce stress on the flex cable and strut bushing, and help keep water out.

The problem is, the stock tube turns and meets the strut at a "level" angle, so it will turn upward when you raise the strut vertically. The modified strut will make this break angle even worse once it's angled down, unless you correct the angle.

With the strut removed, bend the tube so the curve is concentrated nearest to the hull bottom. Then straighten out the bend below this point, so the tube is angled downward as it approaches the strut.

Alan, correct the tube angle, then raise the strut vertically higher like in my photo above. The bounce will go away.

Here's the tube aligned correctly:

http://i1247.photobucket.com/albums/gg629/hydropyropyropyro/1AC29155-F422-47EF-9F23-9AF6EEC033D0-33046-00003B9E87F85F2B.jpg

hydro_pyro
05-27-2013, 08:19 PM
Once the strut is raised high enough and angled downward enough, you will have lots of stern lift effect. This will allow the packs to be moved back more without the blowover risk. Stern lift keeps the back end higher, which will allow the bow to fly higher without the tendency for the tunnel to trap air. Stern lift gives the trapped air an escape path. More speed, more stability, and NO bounce.

Note the pack position... No blowover tendency here on 4s.

http://i1247.photobucket.com/albums/gg629/hydropyropyropyro/D7B532EA-85DE-4D51-9FB6-57D215F3AD0C-33046-00003B9E201DA722.jpg

Speedracer128
05-28-2013, 04:01 PM
Thanks for the explanation hydro. I didn't realize the stuffing tube is bendable/flexible when the strut isn't attached

I understand what your talking about the air escaping from the tunnel by having the strut higher vertically, but I thought by having the prop deeper in the water was more stable. This weekend I ran my boat on 4s and 6s with the strut set low and angled downward toward the back to keep the nose down and my boat has never been this smooth riding at high speeds since I upgraded my motor. This weekend was ruff where I was running but even when I was going fast when the boat would catch air she stayed level while airborne. With 4s my batts were a out the same position as your pic above with 6s slightly further up. But on mine i made new battery trays that sit lower in the hull. I do know that when I reinforced my hull, the extra weight made my boat handle much differently. I think I need a GPS so I can exactly know how all different adjustments affect its speed

hydro_pyro
05-28-2013, 04:54 PM
On some boats, "stable" just means it's stuck more firmly to the water. On a tunnel or catamaran, this traps air and increases the chances of a blow-over. When the strut is higher, there's less prop in the water, and thus there's a lower cross-section of the prop's thrust cone being exerted on the surface of the water. This reduces bow lift and pushes the back end of the boat up, allowing the air to escape out the back, which makes it handle a little more "loose", but more consistent because it's not hopping constantly.

maxmekker
05-29-2013, 05:20 PM
https://www.youtube.com/watch?v=_Uln02dfrSs

This is my run from Sunday. Still a little bounce at high speed. OSE has a new upgrade strut which should be released this week. I'll be ordering that soon with the M440.

cool video man, that thing is fast :-)

Mike Caruso
05-29-2013, 06:37 PM
Hi,
My son has been racing his Miss Geico (V2) in the p-limited offshore class, and we have it dialed in on stock setup with x642 prop. Batteries are just behind the front end of the motor (non-shaft side). Per the tips on the forum, I ground a wider slot in the strut, allowing a bit of negative angle. I have the strut up pretty high-- with the sponsons on the table the shaft does not touch the table-- close-- probably less than 1/8 above it (in the picture it looks like more, but that is just due to the camera angle).

In race conditions (ie, some race-induced chop in the water), the boat rides perfect, no bounce. In glass water, we get a slow bounce. I have not blueprinted the sponsons, and probably won't bother as the boat is doing great in race conditions.

Been too busy coaching my son through the races to get a video, but will try to get one next time.

Chief

Hey Chief,

Great info to help the guys with the same boats get flying and nice of you to put it out there! Makes me want to keep an eye out for one now.

Shane_744
06-18-2013, 02:08 PM
Thanks for the information and pictures on this modification. It took about 1 hour to do this mod to my MG 29. Longest time was bending the stuffing tube correctly and keeping the strut lined up while tightening it. Took the boat out for a quick run and much better. I left the batteries in the same spot that I ran the other day. Bouncing was almost reduced but the bow did wanna lift at full throttle. Boat is otherwise stock. The packs are around the "middle" of battery placement. Ran that for about 2 minutes and the ESC let out some pretty white smoke and black bits.

Arizonaheat
06-18-2013, 04:54 PM
Hi,
My son has been racing his Miss Geico (V2) in the p-limited offshore class, and we have it dialed in on stock setup with x642 prop. Batteries are just behind the front end of the motor (non-shaft side). Per the tips on the forum, I ground a wider slot in the strut, allowing a bit of negative angle. I have the strut up pretty high-- with the sponsons on the table the shaft does not touch the table-- close-- probably less than 1/8 above it (in the picture it looks like more, but that is just due to the camera angle).

In race conditions (ie, some race-induced chop in the water), the boat rides perfect, no bounce. In glass water, we get a slow bounce. I have not blueprinted the sponsons, and probably won't bother as the boat is doing great in race conditions.

Been too busy coaching my son through the races to get a video, but will try to get one next time.

Chief

How do you plan to "blueprint" the sponsons?
Is there a dimensional drawing available?

tlandauer
06-18-2013, 05:25 PM
How do you plan to "blueprint" the sponsons?
Is there a dimensional drawing available?
So-called "blue printing" the sponsons is just a process to make the bottoms match each other and to make sure that they are flat when placed on a flat surface such as a glass table or granite top counter. See this thread:http://forums.offshoreelectrics.com/showthread.php?17514-Miss-Geico-Race-Prep/page2, specifically read from post #43.

jsturess
06-19-2013, 12:59 AM
Longest time was bending the stuffing tube correctly and keeping the strut lined up while tightening it.
Do you taking the stuffing out or does you only bend it with hand strenght? heating?
Mine is hard as a stick (stuffing :-) )

tlandauer
06-19-2013, 01:27 AM
Do you taking the stuffing out or does you only bend it with hand strenght? heating?
Mine is hard as a stick (stuffing :-) )
If you don't plan to replace the stuffing tube, you need to bend it with your hand strength, heating it on the boat will soften the FG exit point and also the epoxy, that is how people take the factory tube out BTW.
You need to take care not to kink the tube. The only portion you need to bend is where it goes into the strut, basically make it straight so you can point the prop down a bit. The suggestion is to insert the largest drill bit possible to the open end of the tube and gently shape ( bend) it.

Speedracer128
06-19-2013, 10:07 AM
@ Alan

What speeds are you hitting on the gps with your setup? Also curious what kv that motor is?

h8onit
07-15-2013, 09:08 PM
Just wanted to say thanks to op for the mod. It has helped my bj29 a lot with the traxxas system in it

AlanD
07-15-2013, 11:12 PM
@ speed racer - it's a leopard 4082/1600. Haven't GPS'd it yet. Took it out yesterday and got pretty much the same performance out of it.

BHChieftain
07-16-2013, 09:36 AM
Well my son ran his boat up on some rocks and ripped up the sponson, so that gave me an excuse to blueprint it! I used West Marine Epoxy Putty. Super strong and sands easily. I'll try to take it out on a test run next weekend before I repaint it.

Chief

BHChieftain
07-20-2013, 05:50 PM
Did a test run with the Miss G's repaired and blueprinted sponsons-- wow, what a difference!! The bounce is even further reduced, but the real benefit is that the sharp edges on the back of the rear sponsons keeps the nose down much further than stock (the sponsons are pretty rounded out of the box). I did not change the strut position at all, and the nose is way down. On this run I pulled the batteries back about 1" (which would have caused blowovers previously). I think I can even reduce the negative angle I have on the current strut position a bit.

I think the only thing left causing any bounce at all on glassy water (with this config it is not a problem-- any racing induced chop lets the boat run great) is the rooster tail hitting the center mounted rudder. The next experiment will be to use an offset rudder. For sports running the center mounted rudder works great as it has equal left/right turning, but my son is racing this one in offshore class so offset should work just fine.

I've been doing free s/b of the stock props and also free strut mods on the RTRs I sell at my webiste (see sig), I think I'll add blueprinting as an option since this turned out so well. The marine epoxy putty is a bit expensive but is the perfect consistency and is super strong.

Here's a video of the run:


http://youtu.be/uewF-c55-zI

Chief

lenny
07-20-2013, 06:20 PM
Hey.:tiphat:
Look like it came out pretty good,
Is mike legally blind ?:bounce:
Look, It's a moving green bullseye. :lol:
I just started testing the setting on mine today,
And got some pretty good video to I think.
I will see what it looks like and than may be post it if it looks ok.

angrycat
07-20-2013, 07:42 PM
hey cheif where did you buy the marine filler? i have my old bj hull awaiting carbon fiber/kevlar inlay and some sponson blueprinting after the seam split

AlanD
07-20-2013, 08:13 PM
Chief, she runs pretty flat and smooth. Can you share some close up photos of the edges you're referring to?

ray schrauwen
07-20-2013, 09:39 PM
I like that stuff. I wonder if I can get it in Canada??


Well my son ran his boat up on some rocks and ripped up the sponson, so that gave me an excuse to blueprint it! I used West Marine Epoxy Putty. Super strong and sands easily. I'll try to take it out on a test run next weekend before I repaint it.

Chief

iop65
07-21-2013, 03:29 AM
i wonder if it would make a difference when you would make the last step 90° angle ?
now it's about 100-110°

the MG v2 iss my first cat ,so i'm not an expert on this matter but in the mono-world we make the point where the water has to "leave" the bottom of the boat razorsharp and 90°

when i was blueprinting mine i was thinking about doing that , but did not
mine has still a very small bounce on flat water

hydro_pyro
07-21-2013, 08:18 AM
Same thing with full-scale performance boats. A sharp, 90° square trailing edge is ideal. The water comes off clean with less drag.

BHChieftain
07-21-2013, 11:40 AM
Chief, she runs pretty flat and smooth. Can you share some close up photos of the edges you're referring to?

Here are a few more pics. I found the putty at a marine supply store that sells West Systems products.

Chief

CHIEFY_44
07-22-2013, 03:34 AM
the biggest thing to do with this hull to stop the bounce is blue printing the hull, I have tried everything in the past and the biggest change was when I blueprinted the hull made all the edges to 90 deg and razor sharp, I also used a rudder offset and angle the rudder forward this helps with the bow ride height, I also use 2x4s in p, I personally cannot see the advantage of having any extra cells infront of the motor its dead weight and just slows your boat down and I am sure its this extra weight that is helping pyro's boat run flat, but how much speed is he losing carrying the extra cells. My MG runs great tlaunder has seen it running and i'm sure he will back me up on this, I run my MG in prod class with a aquqcraft 2030kv motor and the same 2x4s in p on a x442, and when i'm just messing about I put a castle 1515 1y in it with a m445 and it flies, if you can get this boat to around 50mph it just flattens out and flies. There is a video on here somewhere take the time and look for it and you will see what I mean

hydro_pyro
07-22-2013, 06:54 AM
Looks can be deceiving. I'm using the same overall COG as many others who are running a pair of 3s packs. I have blown over three times using this COG. It's NOT bow-heavy. I have tried it more forward, and it tends to plow the front end at lower speeds.

The strut mod helps lift the stern, so the tunnel is not constantly trapping and "burping" air pockets out the back, which is the hallmark of catamaran porpoise in the 1:1 world.

CHIEFY_44
07-22-2013, 07:32 AM
Pyro I am NOT saying the mod doesn't work, what I am saying is the weight of the extra battery has to be slowing your boat, I have done that mod myself you have to to move the strut up as far as you need to and have +/- angle adjustment on the MG v1. The other thing is every hull is different, your setup might not suite my hull and vice versa, there is loads to take into consideration when setting up a boat. For me IMO carrying that much extra weight does not make sense, there again when I'm racing I want to run as light as possible

tlandauer
07-23-2013, 01:03 AM
the biggest thing to do with this hull to stop the bounce is blue printing the hull, I have tried everything in the past and the biggest change was when I blueprinted the hull made all the edges to 90 deg and razor sharp, I also used a rudder offset and angle the rudder forward this helps with the bow ride height, I also use 2x4s in p, I personally cannot see the advantage of having any extra cells infront of the motor its dead weight and just slows your boat down and I am sure its this extra weight that is helping pyro's boat run flat, but how much speed is he losing carrying the extra cells. My MG runs great tlaunder has seen it running and i'm sure he will back me up on this, I run my MG in prod class with a aquqcraft 2030kv motor and the same 2x4s in p on a x442, and when i'm just messing about I put a castle 1515 1y in it with a m445 and it flies, if you can get this boat to around 50mph it just flattens out and flies. There is a video on here somewhere take the time and look for it and you will see what I mean
:iagree:
The first time after my blue printing the ride pad, i thought to myself, big deal, now let's see if it really makes a difference. I was speechless the moment I pulled the trigger. I have also found that dead weight infront of the motor is useless, I put a heavy 5000mAh nicad stick, the boat still bounced.
My mistake is not doing a 90* on the back of the ride pad, after seeing how great yours was running, i will go back and redo them the future.

BHChieftain
07-23-2013, 08:47 AM
Pyro I am NOT saying the mod doesn't work, what I am saying is the weight of the extra battery has to be slowing your boat, I have done that mod myself you have to to move the strut up as far as you need to and have +/- angle adjustment on the MG v1. The other thing is every hull is different, your setup might not suite my hull and vice versa, there is loads to take into consideration when setting up a boat. For me IMO carrying that much extra weight does not make sense, there again when I'm racing I want to run as light as possible

Hi Chiefy_44
Where in CA are you located? I'm in San Jose,

(the other ) Chief

CHIEFY_44
07-23-2013, 12:02 PM
Hi chief I live in Rancho Dominguez just off the 91 fwy

hydro_pyro
07-23-2013, 12:42 PM
Pyro I am NOT saying the mod doesn't work, what I am saying is the weight of the extra battery has to be slowing your boat...

If it's slowing it down, then why am I running close to 60 mph on a stock motor and ESC? The third pack is NOT for dead weight, it's a third 2s pack wired in series for 6s total. It does not run bow-heavy this way-- I have seen three blow-overs with this center of gravity, but rarely any bouncing.

When I run 4s (two packs), I put the side packs slightly more forward and it still runs nicely, with a high-flying bow, and no bounce.

6s:
http://i1247.photobucket.com/albums/gg629/hydropyropyropyro/8659A2F5-C7C2-450C-9240-73960F41FE99-2025-0000046B7C296952.jpg

4s:
http://i1247.photobucket.com/albums/gg629/hydropyropyropyro/D7B532EA-85DE-4D51-9FB6-57D215F3AD0C-33046-00003B9E201DA722.jpg

If anybody is wondering... I made the pair of spacers in the photo from thick commercial rubber roof sheeting. Each one is a rectangle of flat rubber with the motor wires threaded through three tight holes. This keeps the stock motor bullets cooler, and keeps them from making contact with anything if the heat shrink gets hot enough to soften. Works great.

BHChieftain
08-05-2013, 09:44 AM
Here's another video from a run we did yesterday-- since blueprinting brought the nose down I was able to set the strut completely neutral, no negative angle. The bottom of the propshaft is even with the sponsons (just put the boat on a flat table, and set the strut so everything was level). So bottom line-- if you blueprint with 90 angle off the sponson, you could skip the strut mod altogether.


http://youtu.be/5FWENVvbAoc

Chief

iop65
08-05-2013, 10:53 AM
runs great!
hope to achieve the same !

maxmekker
08-05-2013, 11:25 AM
Yeah that was super to watch, great Place to run to. Love those Places were you get a bitt above water Level.

skeeler
08-17-2013, 09:34 AM
Very informative thread. Subscribed.

BHChieftain
08-17-2013, 12:58 PM
I'm pretty sure that's all high-quality aluminum, but I could be wrong. Aluminum tends to wrap itself around the Dremel bit, clog up the abrasive surface, and sort of "burn" away while you're grinding... This can make it more difficult than some other materials.

I used a spiral-fluted metal cutter bit, and finished with a small stone bit.

Hi,
I made this mod for a few customers and this time used a rattail file to widen the strut slot-- much easier than the dremel.

Chief

Sent from my XT890 using Tapatalk 2

Speedracer128
08-17-2013, 08:22 PM
I can't see a link to video. But that is impressive to have am MG near 60 with stock motor.

BHChieftain
11-02-2013, 06:00 PM
I have a Word doc that has both Miss Geico and Blackjack mods and setup I have made documented, and also has a great overview on prop selection. I have not yet updated it with the blueprinting process, but I will get around to it this winter.
If anyone would like a copy of it, please email me at jqhydro@gmail.com

Chief

96motorhead
11-19-2013, 10:42 PM
Has anyone ever done the strut mod and put the steep angle on the OSE shaft? I ask because I did it to my stock blackjack flex shaft and the shaft sheared after 1 lap or 10 seconds on the water. I got an upgraded OSE shaft but I'm afraid to put that steep of an angle on it as I don't want to go swimming again.lol

hydro_pyro
11-25-2013, 06:18 PM
There isn't any stressing angle on the shaft unless the mod was done incorrectly. The stuffing tube MUST be bent/adjusted as I described, or you will have a sudden angle where the tube meets the strut, which could cause breakage as you encountered. Check out the photos on page 2 to get a better look.

96motorhead
11-25-2013, 09:55 PM
How did you bend the stuffing tube without kinking it? Did you just keep the flex shaft in it while you bent it?

BHChieftain
11-25-2013, 10:15 PM
I gently bend with my hand. You can use a drill bit that just fits in the tube to help protect from kinking as well.

Chief


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hydro_pyro
12-08-2013, 08:53 PM
You won't need to force it enough to kink it. Just concentrate the bending force near the base of the tube where it exits the hull, then slightly straighten the tube where it approaches the strut-- this is especially important to keep the tube lined up with the strut's downward thrust angle.

mannytx1
01-26-2014, 02:17 PM
NO more WA WA WA 111089111090111091
strtu closer to the transom / sponsor is more stable catamaran111242