I have an OS 91 surpass for my 46 UCD and it will hover just fine but I was trying to think of ways to increase power for a stronger pull out. Maybe a Tune pipe or readjusting the rocker arms. Does anyone have any suggestions?

52X

The rocker arms have never been gap cnecked. That would be a great start for more power. May-be you should go to "gramp-pas" house, and he will show you how.

OR

Wax his boat, and he might just buy you a YS 110.

14X

Matt52X, on the .91 Surpass, according to Harry Lagman here at RCU, a significant gain can be had with an aftermarket exhaust system. I brazed an extension on a friends header pipe and noticed when the bend was made at the factory, the pipe was partially collapsed. Also the tubing is unusually thick. Performance Specialties is one of the vendors of aftermarket exhaust systems.

Well I'm a car mechanic and I know where horespower can be added but what's out there? if I could get ahold of a carb that'll suck ur brains out and an Exhaust to spit it out that would be great!!! But where and who should I talk to or start?

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Grandpa soon enough. Flying season is almost here and I'm getting back into mode. I mailed Tim my AMA and would like to get over and put an engine in that Kaos. I've also been on the Aero fly sim and have seen some progress seen last year.... Heli pilot here I come Theres other things Id like to talk to you about so I'm trying to get over there but it's hard with track because it's 6 days a week 7 in the mourning.

Give it a dose of 30%.

Make your own hipo carb. Just drill the bore and the barrel just like you would do on a car engine. Works great!

well that would def. work (drilling) but I want to keep it a little clean. I've had problem, sometimes the engine will overheat in a long hover if i'm not paying attention to the engine heat. So if i went 30% do you think the engine would overheat faster?

Great ideas, keepm' comin!

It's giving you about as much as it can give. There are some small improvements out there but not much. You migh consider selling it as is and getting an engine with more power.

Get you some 30% fuel. You will get a good increase in power and your engine will actually run cooler since you will have to open the needle valve for more fuel flow. This is why your heli fuel is 30%. They benefit from more power and cooler running engines. Helis do not get the good airflow that fixed wing craft benefit from. If you are running 4 stroke you will not have a problem. On the 2 strokers you want to listen for any detonation. If you do have detonation it is a simple fix of adding an additional head gasket which will lower the compression a tad. I am pretty sure you can then do your hovering thing without having heat problems and also pick up quite a bit of power. This is your simplest and cheapest fix for heat and power. Good luck.

Hi!
You would not gain much power by boring the carb . 30% nitro might gain somewhat but not much compared to if you altered the compression (lower compression) and changed to electronic ignition and spark plug (still running methanol of course).
If you run 30% nitro see to that you set the engine a little rich so it will not overheat in the hover.

Regards!
Jan K
Sweden