My dad is having an odd problem with a new Webra .32 heli enigne. It has about 2 hrs. total time including a proper break in on the test stand. It will run fine in the heli for about five minutes. Then it begins to lose power to the point that at full throttle it isn't even making enough power to hover. If I drop to half throttle it runs well enough to fly but isn't making full power. It is putting out plenty of smoke at any throttle setting, doesn't sound lean at all it just loses power. My first thought is bad bearings but it's a low time engine. It isn't fuel, we've tried 30% heli fuel from Morgans and regular 10% CP like we run in all the other flying machines, fixed wing or rotor. Same problem regardless.

Seems to me that if it were a mechanical problem or overheating it would show up in the first minute or so of the flight but it takes about 5 minutes. The servo operates the throttle correctly. Ideas anybody? Thanks.

Rick H.

Rick,

I dont fly helicopters......but clearly there is a problem either with the engine or the mechanical system of the helicopter. I understand that cooling in a helicopter can be a real problem (the fan is small & the engine shoe-horned into a very tight & congested space).

If the engine is slowing down at full throttle, but after 5 mins it begins to slow down, certainly sounds like an overheating situation.

As a starting point, I suggest you bench run the engine using the same fuel & watch what happens. If it will run out the tank without any problems, then the engine is not the issue.

Is there tightness in the helicopter bearings? Binding of shafts?

As I mix my own fuel, I am not familar with the fuel you are using. What is the oil content? Regardless, I would suggest AT LEAST 20% oil.

If all the above are ok, then perhaps the cooling needs to be increased. Extra ducting for both the in & out air may be the answer.

Finally, is the engine large enough for the helicopter? A more powerful engine would not need to be run at wide open throttle & do the job more easily.

Bone

The 5 minute length is telling you it is a fuel delivery issue when the tank goes down. Are you sure the webra heli engine will handle 30% ? If it runs the whole tank on bench on different tank setup. You have found the problem. What color is oil coming from muffler ?

Hi!
The problem is lack of fuel! Or...a bad glowplug (don't think so in this case).
So check the fuel tank and lines to the engine ...but most probable is that your father is running the too lean!
That simple!