Problem with Phoenix Laser 40
 

Hi,

I flew the airplane for the first time today and it was really bad.... The airplane was very unstable in the roll axis, a slight input of the ailerons and it was all over the place. I was not able to trim it so it would stay level. I have some experience on low wing airplanes since I have been flying an extra 300S from Great Planes as well as the Patriot XL. The ailerons throws were set up by the instruction at +/- 10 mm and I had 50% expo on them! The C.G is 140 mm by the instruction and I balanced the airplane laterally as well. I checked the incidence and the left and right half wing are within 0.5 degrees from each other (1.5 to 2 degrees). The stab incidence is also about 1.5 to 2 degrees. The engine is a super tiger 51. Does anybody has flown this airplane with success? What could be causing the problem? I am going to reduce the ailerons throws but I am also wondering if I need to move the C.G forward?

Thank you for your help,

Le fou

RE: Problem with Phoenix Laser 40
 

just by the sounds of this it does seem to me that the COG is not where it should be. you should try moving the cog more forward to say 100 mm and re test the model then adjust cog from there. i must say many arf kits do have incorrect cog settings and do need sorting out. as i said move your cog more forward.

RE: Problem with Phoenix Laser 40
 

I would guess 140mm for the balance point to be a bit aft for a 40 size plane. Sometimes the mfg gets confused and states a balance point for a larger version of the same model. Your aileron throws don't appear excessive, still, toning them down may be a part of the solution. It looks like you are on the right track. Good luck.

edit: I just checked the Tower site and got some CG comparables for other Phoenix 40 size models.

Extra - 90mm
Yak 54 - 105mm
Sukhoi- 110mm

RE: Problem with Phoenix Laser 40
 

Thank you everybody for your replies. I think that I will move the C.G forward and try to fly the airplane again.

Le fou

RE: Problem with Phoenix Laser 40
 

Hi Le Fou

I also got the Phoenix Laser 40 awaiting test-flight and would like to ask,
if You re-tested yours with the new CG , if it improved, and where You
currently positioned the CG .
Thanks

Giuseppe