Whip 20 Help me break 70mph

[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.

[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'

[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]

Revs are your friend :)

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

[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.

[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]

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..........

[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.

[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.

[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.


.

[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.

[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.

[Heaving Earth]

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

[Heaving Earth]

Have you considered 5s?

[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?