LapCat I (27 inch) with a stock K&B 7.5?

[Mr. FastBoat]

LapCat I (27 inch) with a stock K&B 7.5?

Hello all. I am a newbie to rc boating so some of you may laugh at my question. I bought a LapCat I (27inch, made for a 3.5) off of Ebay and the guy said that a stock K&B 7.5 would work fine on it. Another guy i talked to said that the boat would be uncontrollable with a 7.5. Assuming that i will use 15% nitro (i fly planes so i'll just use the same fuel for my boat that i do with my planes) and that the boat will be balanced correctly and that the motor is positioned right, will the boat be unstable and/or uncontrollable under full power? thanks for any comments.

 

[Propjockey]

Re:LapCat I (27 inch) with a stock K&B 7.5?

7.5 on 27 inches? Uncontrollable? Let's just say it's a good thing you have experience with R/C planes! FAI, hopefully. ;D

7.5 may be a weeee bit much for that hull. Do you already have the engine, or just shopping?

 

[waterbug]

Re:LapCat I (27 inch) with a stock K&B 7.5?

NO WAY !!! I doubt it would stay on the water at half throttle !!!!!!

Do your self a favor and get a 3.5 !!! You may have to add weight to it to keep it on the water.

 

[Mr. FastBoat]

Re:LapCat I (27 inch) with a stock K&B 7.5?

I bought the engine first locally. I bought the boat because he told me that the 7.5 would be fine!! GRRR!!! But i bet it would be fast just before it flew off the water!!!!!!!!

 

[Propjockey]

Re:LapCat I (27 inch) with a stock K&B 7.5?

It would still be fast 30 feet AFTER it left the water! ;D

 

[rcnut38]

Re:LapCat I (27 inch) with a stock K&B 7.5?

Can you say Water missile LOL

 

[snowdog-2112]

Re:LapCat I (27 inch) with a stock K&B 7.5?

Mr. Fastboat,

All previous posts are valid IF (and that's a big IF) you can get the boat launched. Experience with an overpowered boat shows that 95 times out of 100, the boat will roll over upon launch due to prop torque. As you can tell by the posts it will be a pain to drive er, uh, fly.

Snowdog

 

[MarkScott]

Re:LapCat I (27 inch) with a stock K&B 7.5?

Doubt very much this would work. Years past, I watched a gent that tried a 7.5 on a Dumas 3.5 Hotshot - the non-Sprint model.. It worked ok if 1/2 or less throttle was used. When he opened it up, flip.... Do yourself a favor and get a 3.5 and a larger boat for the 7.5..

Mark....

 

[vanduzer]

Re:LapCat I (27 inch) with a stock K&B 7.5?

I raced the lap cat for years and even with mod. 3.5 it was too much power for the boat. If you want a low priced 7.5, Jerry D. wof is cheap to built a couple sheets of ply and some pink foam.

 

[nitrotoys]

Re:LapCat I (27 inch) with a stock K&B 7.5?

WOW Thats going nuts with a tunnel.

If you can add 8 or so inches to the one you have the 7.5 would probably work.

if your going to run it that way, Please POST PICS.