SR80 pro mod - issues

[Apbling]

Hi all

I have an SR80 pro that I was hoping to speed up just a hair and also convert to 3/16 prop from its stock 4mm.

Stock motor (1750 KV outrunner) was replaced with a leopard 3660 2050 KV inrunner. The ESC was replaced with a raider 150amp. Battery was kept at 4s. Speedmaster 21 strut replaced the stock. The stock prop was a 40mm unknown pitch, which I replaced with a graupner 42mm 1.4p. Everything is stock. The maiden was rough...heavy accel would pop it out of the water and flip it. Easy accel was ok but I had trouble with it tracking straight. Any hard accel or throttle above 75% and the think would veer one way or another, flip or barrel roll. I tried level strut and even negative angle strut. I added tons of trim tab. Nothing helped. The boat used to be fantastic and I was hoping to just speed it up some. A guy on YouTube has these boats on 6s with with 2200+ KV motors on similar props, but he swears up and down I need to upgrade the turn fins. I can do that..but I?m thinking the prop is too large...my ft011 is 4s and like 2400 KV motor and it?s prop is tiny - and the boat isn?t that much smaller than the SR80. What are symptoms of inadequate turn fins or prop too large?

[srislash]

I am not familiar with an SR80. Any chance of a pic of the hull, maybe a pic of the strut setup.
A lot of views here and I’d love to see if I can help.

Shawn

[ray schrauwen]

https://www.amazon.com/VOLANTEXRC-Ve.../dp/B07Q22K96G

[Apbling]

Sorry for the late reply guys. I’ll post some pics. But I had the strut level at first. Then silly negative with lots of trim tab - no help.

3F0B526C-EA10-4D1F-BB9E-14C8202F6FCE.jpgEB40FC35-B603-48A7-8600-CE611435A249.jpg0517B005-3FFB-42EE-ACA3-11BF42C9EA0A.jpg

[30nitro]

I have 2 vector 70's...... same hull just a little smaller..... those hulls don't like bigger props...... You're probably overpowering that hull also with that setup...hence your handling issues....

[Apbling]

Ok. My plan was to go back to stock prop and go from there.

[srislash]

Ok. My plan was to go back to stock prop and go from there.

You can experiment with pitch perhaps in a stock size prop or smaller if you pitch up.

[Apbling]

I went back to the stock prop (40mm, unknown pitch) from the gaupner 42mm 1.4p. WORLD of difference. Boat is again on rails. I can hammer the throttle and it doesn't misbehave like before. Is it safe to say that the stock prop is likely a higher pitch prop than 1.4, giving me less thrust out of the hole but maybe a higher top speed?

That being said - I'd like to try some different props, but I really don't have the budget to buy a bunch of metallic props just to test with. Is there a source out there other than OSE and gaupner that I can get different pitched carbon fiber (like gaupner) props to test with? Alot of the plastic ones I see won't fit the 3/16" shaft, or aren't rated for my RPM's.