Whip 20 Help me break 70mph

[kevinpratt823]

Whip 20, Neu 1515/1Y, SK180, 4s2p(5000mah each) Dinogy.
I got 64.6 with an ABC H7, 67.4 with an Octura 1650, temps still reasonable after 4 min. And I'm looking to break 70mph before winter comes here.

ABC H10 out of stock everywhere, any recomendations? Preferably something available on OSE.

I'm not extremely familiar with hydro props yet............and I know I can prob get another couple mph as dial setup also.
Thanks for any experienced input!

[Shooter]

Awesome quest!! Just my opinion, but you may be close to the limit with those props, unless you don't mind reducing run-time. I was running an M545 with the same esc/motor in my stealth, but I could run it till the batts dumped with no temp issues.

If it's just speed you are interested in, removing the turn fin is good for ~2mph. Also, have you considered some smaller diameter, higher pitch SAW props? They may require a hand launch.

Good Luck!!!

[kevinpratt823]

Awesome quest!! Just my opinion, but you may be close to the limit with those props, unless you don't mind reducing run-time. I was running an M545 with the same esc/motor in my stealth, but I could run it till the batts dumped with no temp issues.

If it's just speed you are interested in, removing the turn fin is good for ~2mph. Also, have you considered some smaller diameter, higher pitch SAW props? They may require a hand launch.

Good Luck!!!
Not sure I can keep it on the water without the turn fin, I don't get many totally still glass-water days at the pond I go to. I'm not too concerned with runtime if I can break 70mph. Once I do it I'll prob go back to the H7 for most regular running.........
I wouldn't know where to begin with SAW props. I do have a 1745/3 back-cut/cupped tips, and a 2047 back-cut(both were some of my early attempts at modding props) from experimenting with SAW runs in my old UL-1 though, thought about trying those......
Thanks for the feedback, anyone else?

[Heaving Earth]

Have you considered 5s?

[Heaving Earth]

Wait, I think I remember it won't fit 5s packs

[785boats]

As strange as it might sound, the H-5 gets me more speed than the H-7 on my 33" Whiplash with the same KV motor as yours. It allows the motor to rev higher. I'm not saying it will do the same on yours, but it might be worth a try. A Prather S225 also works well in that rev range.

[kevinpratt823]

As strange as it might sound, the H-5 gets me more speed than the H-7 on my 33" Whiplash with the same KV motor as yours. It allows the motor to rev higher. I'm not saying it will do the same on yours, but it might be worth a try. A Prather S225 also works well in that rev range.
What batt setup do you use, mine is a bit heavy with 5000's. I do have an H6 that I haven't even tried though.

And Dana, (2) 5s won't fit, I though about trying one though, but the COG will prob be too far back.

[Fluid]

You could run 5S1P and use lead to get the right CG position. Weight can be your friend when trying for high speeds in an air compression hull. Other props to try would be the ABC 1718 (for 5S) or the ABC 1716 (4S). They may unload a bit more than the elephant-ear props.


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[785boats]

What batt setup do you use, mine is a bit heavy with 5000's.

Here in Australia we can only run single packs for racing so it's a 5000mah 40C pack in mine. As Jay said, weight is a good thing. I need to run 280grams of lead in the front of mine to keep it on the water. It's going nowhere near 70mph either.

[kevinpratt823]

ABC H-10 back in stock, just ordered thet and a 1716. Wish me luck! I'd really like to do it on 4s, putting 5s in would feel like cheating, plus that's higher than I like to go for rpm's.

[kevinpratt823]

First tries with the 1716 got 60 mph, and very slow to get on plane, and 65 mph with an H-10, still kinda slow to plane, so far my best was still the 67.4 mph with the Octura 1650, but I'll try the others again today with a bit of strut adjustment..........

[detox]

First tries with the 1716 got 60 mph, and very slow to get on plane, and 65 mph with an H-10, still kinda slow to plane, so far my best was still the 67.4 mph with the Octura 1650, but I'll try the others again today with a bit of strut adjustment..........

Add a little cup at tips to your 1650. Bend/twist toward center of hub and upward at tips about 1/64-1/32". Regular pliars will work for this.

[kevinpratt823]

Add a little cup at tips to your 1650. Bend/twist toward center of hub and upward at tips about 1/64-1/32". Regular pliars will work for this.
Funny, just got back from the pond and I cupped it a bit before I even ran it, hadn't even read this yet. I also drilled a hole in the strut bracket, which was for a mono, to bring the strut(sport 20 extended type) back in to the transom. Ran good for a minute, until it filled up with water from a water line that came free on the esc. Brought it back in and the GPS wouldn't come to life. Hopefully try again tomorrow........
My 1650 is back-cut a bit also, I may get another raw one to start from scratch with.

[Kris Flynn]

Revs are your friend :)

On 4s1p the hull can do 92mph+ average both ways through the traps ;)

[kevinpratt823]

Revs are your friend :)

On 4s1p the hull can do 92mph+ average both ways through the traps ;)
I thought I had read that somewhere........
Any tips on what direction to go for me?

[Kris Flynn]

Turn fin off
Sharpen up all ride surfaces
Shorten rudder
More revs, 50mm is a big prop for a small boat to handle 'nicely'

[detox]

I have heard of water lines bursting during high speed saw passes. You may need stronger hose...i forget what type to use. Maybe two stroke fuel line.

I would not run strut too deep. This will lift stern and cause sponsons to run wet. 1/2" or shallower from bottom of stern to bottom of strut may be a good start with that large prop.

1 degree more AOA on sponsons would help also. I have cut the 1 degree ride pads using miter saw. Then glue on and finish.
4s2p is pretty heavy for the standerd width ride pads, i would also widen them 1/8"
4s1p would work for two saw passes, but be easy on the throttle during start.

[kevinpratt823]

Turn fin off
Sharpen up all ride surfaces
Shorten rudder
More revs, 50mm is a big prop for a small boat to handle 'nicely'
Any reccomendations? I still haven't run the H-6.....or do you think I should go back to the H-7/H-10, or 1716 and tune it in?
Ride surface are reasonable, but considering the hull has broken 90mph on 4s, I don't think it's unreasonable(for me) to break 70 and still turn and handle OK without going the full SAW setup route with no fin and short rudder, I would prefer not to, and I will learn more if I try to get there without doing so, but it will be a last resort to reach my goal if I am not there before it gets too cold out.
Thanks for your input!

[kevinpratt823]

I have heard of water lines bursting during high speed saw passes. You may need stronger hose...i forget what type to use. Maybe two stroke fuel line.

I would not run strut too deep. This will lift stern and cause sponsons to run wet. 1/2" or shallower from bottom of stern to bottom of strut may be a good start with that large prop.

1 degree more AOA on sponsons would help also. I have cut the 1 degree ride pads using miter saw. Then glue on and finish.
4s2p is pretty heavy for the standerd width ride pads, i would also widen them 1/8"
4s1p would work for two saw passes, but be easy on the throttle during start.
Actually water line just pulled off a barb, I put some Great Planes clips on them now. It could have worked free a bit when installing, as my SK180 sits just under the front cowl on top of the packs.
Strut is right about 7/8", I will try lower, but the problem is more keeping the sponsons on the water, and not blowing over, I'm trying to control that with the strut angle also, but if I go too flat it gets the wa-wa's/prop hop.
Your ride pads do look nice, what type of wood did you use, and how did you seal and attach them? I did something similar on my UL-1 before with cedar shingles, but it's prob not the best material.
I bought the hull from Ray Shwaren, I know he did some modding to the ride pads, but I'm pretty sure he just raised them 1/8", looks like they were just filled in from the step all the way back, as I have no initial step at the front, possibly catering to a lower power setup.
Thanks for the input Detox.
Another area I have for improvement is the turn fin. I could take it off, as Kris mentioned, but I'm not too keen on running without it where I go, I don't have a huge area to slow down and make wide turns without going into the choppier water or losing visibility. It had a Virginia Craftsman fin, which was rather large with a flat bottom/curved. I drilled a new pair of holes to bring it up some, but it still hangs down about 2-3/16"(not sure if I can grind the top down more and drill another set to raise it up again), I also took the front corner off and rounded/sharpened it. I am still running it with a lot of down angle, which is surely causing some drag, but I'm having trouble keeping it on the water if I don't.

Perhaps the modded ride pads are holding me back by catching too much air or something, would some type of air dam be worth looking into....?
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[Heaving Earth]

How about a straight turn fin Kevin

[Heaving Earth]

Also, what affect does moving the fin further away from the sponson have?

[raptor347]

My whip went 93mph and change in 2007 with a 1521/1D, 4S1P 25C 5300's, V947. No turnfin, knife blade rudder and some minor sponson mods.

Unfortunately, it didn't survive the crash at 100+.

[detox]

My whip went 93mph and change in 2007 with a 1521/1D, 4S1P 25C 5300's, V947. No turnfin, knife blade rudder and some minor sponson mods.

Unfortunately, it didn't survive the crash at 100+.

Thanks for showing those pictures. You have a good memory. I bet trimming the inside bottom of tips reduces lift.

[detox]

[QUOTE=kevinpratt823;526937]Your ride pads do look nice, what type of wood did you use, and how did you seal and attach them? I did something similar on my UL-1 before with cedar shingles, but it's prob not the best material. [QUOTE]

I made those from maple, but softer woods will work also. First i cut square a short piece of 2" x 4" wall stud in the miter saw. Then i superglued a piece of maple to the end of stud and cut all pieces 1 degree. You will need a sharp blade to get good cut on hard maple. I sealed wood with good low viscosity epoxy then painted.

A less deep strut setting and maybe a little weight added to stern may help your stern hop problem.

[Heaving Earth]

If I were doing ride pads, I would use thin carbon fiber plate. seems like it would be a good flat solid material

[kevinpratt823]

My whip went 93mph and change in 2007 with a 1521/1D, 4S1P 25C 5300's, V947. No turnfin, knife blade rudder and some minor sponson mods.

Unfortunately, it didn't survive the crash at 100+.
Thanks for chiming in! It looks like your ride pads are similar to what I have, but I don't have the corners cut. Do you think it's reasonable for me to get over 70 with some minor adjustments and maybe the right prop? Your setup was turning 10,000 rpm's more than mine, so obviously that's a big difference. I like the way she runs for the most part as is, just looking to get her over 70 for a personal best, without making it a SAW boat. Anny suggestions are welcome.

[kevinpratt823]

Sent from my SCH-I535 using Tapatalk 2

Drilled the turnfin again and got it up to 1-7/8" down from ride pad, with a bit less downward angle, also raised the strut up to 3/4", completely flat. Made one pass with the back-cut, slightly cupped 1650 that looked very promising, then lost the prop when the nut came loose, as the hub is kind of long on that prop and the setup didn't allow much threads(I will be changing that), retrieved the boat, left it taped, tried a heavily back-cut 2047 and a 1745/3 just because I had them, but both props need a lot of angle on the strut so they didn't go all that well as is, then put on the H-10 and ran great for the last few minutes. GPS came back with 71mph!:banana::banana::banana: It was definitely either the H-10 or the 1650, looking forward to trying to back it up when I can get back out! I am very pleased with the trial and error/learning process, and above all I learned that I have been running the strut too deep, and 1/8" higher made a big difference all around for me, as I did not blow over once during the 2 sets of packs, also got a better feel for turn fin adjustments. It helps that the water was nice today also.

Thank you everybody who contributed and gave me food for thought, and keep it coming!

[Heaving Earth]

Nice job Kevin!

[kevinpratt823]

Nice job Kevin!
Thanks man. I should abb that the first set of packs ran 66.4mph with the 1650, and strut was at 5/8", I dropped it down an 1/8" for the run that got the 71mph.

[Heaving Earth]

well i think even a tiny change on the strut will make a big difference in the angle of attack in which the sponsons hit the water. find the sweet spot and you're golden

[Fluid]

I am confused. You were running the strut too deep yet you lowered the strut even more to go faster??


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[kevinpratt823]

I am confused. You were running the strut too deep yet you lowered the strut even more to go faster??


.
Before today, I had been running the strut at around 7/8" to 1", and trying to get what I wanted with changing the angle. I had the idea in my head that this was already pretty shallow, and the boat seemed wet, but actually I think it just seemed wet because the prop was running too deep and throwing water.
I started today off by going rather far in the other direction as an experiment for myself, and I set the strut at about 5/8" the first run. At 5/8" I saw an improvement in the ride, and got 66.4mph, but felt the prop wasn't quite as loaded as it could be and the transom wasn't far enough out of the water. I lowered the strut a bit to about 3/4", which is still 1/8" higher than I had been running it previously, does that make more sense now?

I will add that it was a combination of input about unloading props from you(Fluid), higher revs(Kris Flynn), and shallower strut(Detox) that provoked me to continue in this direction, so thank you guys again for your input!

EDIT: I just re-read my previous post, I said "I learned that I have been running the strut too deep, and 1/8" lower made a big difference all around for me", I meant to say "1/8" HIGHER", I will go back and edit that............sorry for the confusion.