Strut and rudder location (cats)

[T.S.Davis]

Unless lightening strikes me dead on the spot we're racing. It will be just like that scene from Cadyshack.

I could scrounge up the time and even have the knowledge to make my own molds. What I lack is the motivation. The ROI sucks on custom boat work. My opinion only of course.

I have a cool scale all framed up that I can't seem to find time for either.

[AlanN]

Time is a precious commodity. I'll try to make the effort and drive on Sunday. Do you guys run spec rigger too or is that just sometimes? Still have to build another lsh.

[T.S.Davis]

If you guys are coming up be sure to email Fred your classes.

We run the riggers if we get enough. Mine is in 11 pieces give or take. I have a cat to build before Sunday that isn't here yet so my rigger wont be back together in time. I don't think there will be enough the Sunday. You and Howard have them. Talk Fred into bringing his out to and you'll have enough.

Same thing with 10th scale. We run em if they show.

[RandyatBBY]

AlanN is right about the rudder. I used a long bracket at one time when the power required it but as I tested and got more power I ended up with a rudder with the trailing edge of the prop and the leading edge lining up. Things have chnaged over the years in FE a lot.

[dana]

i have the mono strut bracket on my MM. im wondering if shortening it up a bit would be better. pretty much drill a new hole and move it up

[larryrose11]

I just went from a short strut to a long one on my Cheetah.
The previous one had the drive dog in line with the front of the rudder. The new strut is extended, so the rudder is in front of the prop. Handling has become non linear. It won turn as well while moving, and I have to let off the throttle to turn well. Im going to go back to a shorter strut.

[modvp55]

Larry might be due to rudder in front of prop seen that be an issue on real boats but new to electric rc. My Cheetah has the front of the rudder 3 and 5/8 from transom with back of prop about 1/2 inch in front of rudder and it turns like on rails. Further back rudder or strut more leverage. Further back adds bow lift.

[rayzerdesigns]

when you have a longer strut..it really puts leverage on steering..i try to keep them as short as possible..same with rudder..the farther back you move it..yes it wont want to blow over as much..but it wont want to turn..and then when it does..it will try and hook..i have some other ideas for cats terry..you know this is my favorite class..if you ever get out to az..I will let you take a fe w laps with my prototype..it is going to be a force to reckon with this year..think lsh speed..and stable..

[TRUCKPULL]

Seeing that we are bring this thread back to life.
lets keep things in order.
1 -- Hull , power-motor's & batteries, prop size and rotation (inward or outward for twins)
2 -- Twin drive or single
3 -- Race, Offshore, or strait line speed
4 -- Front edge of rudder in prospective to prop or drive dog
5 -- If single -rudder offset in inches
6 -- Strut length - Front of prop from rear sponson in inches
7 -- Strut angle degrees +Down -Up from bottom of Sponsons
8 -- Leading edge of rudder in degrees + Out - In
9 -- Rudder shape (example) Parallel 1"wide top to bottom, Leading edge Tapered 1"wide top-7/8" wide bottom
10 -- Rudder depth below sponson bottom

I know this is a lot of information to give up, but if a person is looking to setup a P-Spec Cat,
information on a 6S twin is not going to help him and vice-versa

Let me start off.
1 -- Hull Mean Machine 2-- 29 1/2" long, motor's - TP 3674-2200KV, 4S2P 5000mAP, props 440/3 left & right outward rotation for better steering at speed.
2 -- Twin drive
3 -- Race & Offshore
4 -- Front edge of rudder at set screw of drive dog
5 -- If single -rudder offset in inches --N/A
6 -- Strut length - Front of prop from rear of sponson in inches 3 1/2"
7 -- Strut angle 2 degrees +Down from bottom of Sponsons
8 -- Leading edge of rudder 2 degrees + Out at bottom
9 -- Rudder shape Leading edge Tapered 1"wide top-7/8" wide bottom
10 -- Rudder depth below sponson bottom 3 1/8"

Larry

[kfxguy]

Larry might be due to rudder in front of prop seen that be an issue on real boats but new to electric rc. My Cheetah has the front of the rudder 3 and 5/8 from transom with back of prop about 1/2 inch in front of rudder and it turns like on rails. Further back rudder or strut more leverage. Further back adds bow lift.

I once thought that if you pushed the prop further from the transom then there would be less bow lift. Kind of like extending the wheelbase like a dragster. Well after talking to the owner of speed master, he convinced me otherwise. Now that I think about it, my 32" Rivercat (the first one) was soooo stable and not flighty with the regular short strut on it. Then I put the adjustable strut on it which also pushed the prop a bit further back, made it become more flighty. I initially thought it was tuning I had to start over at....but now that I look back on it, it took flight much easier. I think I moved the prop back 1/2" to 3/4". Next Rivercat single I build for myself will have the prop closer to the transom.