Experts required

[Glenn Philbrick]

I have a frustrating problem. I have recently completed my second Cloud models Mosquito and cannot get it to fly smoothly. It was built in the same way as the first which was brilliant to fly hence the second. I'm using the same power train, the C of G is correct and I've even tried moving it forward by 5mm, the thrust line of the motors is level with the wing and both wing and tailplane are also level. The symptoms are that the model is very sensitive to elevator, the slightest movement has it balloning upwards, I have 40% expo and less than 5mm movement but still it flys in a series of undulations and I cannot trust it to fly too low as I am constanly fighting it to keep it level. Has anybody any pearls of wisdom? My only thoughts are to move the Cof G even further forwards

Thanks

[simon burch]

If its that sensitive to the elevator, I would think the C of G is too far back.

Edited By simon burch on 11/03/2012 18:09:19

[Lindsay Todd]

I am not familiair with the model so can't coment re incidences or thrust lines however my imediate thought would be CG position based on the sensitivity of the elevator. Is there any variation at different throttle / power settings?

Linds

[John Cole]

Are you using the same radio set-up: same bits and same settings?

[Glenn Philbrick]

Thanks for replies so far, John to answer your question same radio differant Rx as previous one was the cause of the demise of the first mossie.

Thanks,

Glenn

[Phil Cooke]

does it fly like this under power AND on the glide?

[Phil Cooke]

and another thing to check, are your flight batteries secure? It might balance ok on the bench but if they can move maybe they are moving rearward at launch and leaving you with a rearward balance point...

there are other possibilities, for example is the tailplane warping under the load of the servos when the elevator is applied - giving you effectively more input than you think...

We need to address a number of points here one by one and isolate the problem... first thing is the glide/power test as per my previous mail...that will close the CofG issue and suggest its related to thrust lines/prop wash effect.

[Glenn Philbrick]

Thanks Phil. I think you may be onto something . Thinking about it landing from the glide exhibits the same effect so that would rule out thrust line. The flight batteries are very well secured. I think I will try some more lead up front and move the C of G some more.

Thanks

[Engine Doctor]

Hello Glen . Have you put the elevator push rods in the same hole in the elevator horn? If you have moved it nearer the elevator any movement will be increased .Try moving it out to the last hole on the horn and it will soften the response. As said earlier ,it also sounds as if the CG may still be too far back.where does it balance ?

[Glenn Philbrick]

Thanks for the reply. acording to the instructions the C of G should be 90mm back from the leading edge of the radiators as it was on my old one, I've now added more lead up front and moved the C of G to 83mm. Flying tomorrow so should know then if it is better.