Strange Problem
 

Hi Guys,
After about 25 years off, I am getting back into planes again. I bought a Hobbico Superstar 40 arf trainer. I installed a tower hobbies 46 with a 10x7 A.P.C. prop. Now comes the strange problem. When the plane lifts off. It will not turn to the left. When I try to force it to turn, it climbs like crazy. Now............ when I cut the power. It turns just fine. At half throttle it flys just great. I have not tried to turn right at lift off at full throttle, so I can't tell you if it will turn or not. Has anyone had this problem, any ideas on how to fix it.? Any help will be appreciated.
Fred

RE: Strange Problem
 

very odd problem... take a look at the prop/engine in relation to the fuse standing over the plane and behind the wing saddle... do you see the engine/prop pointing WAY to the right? that would explain it not wanting to turn left under full power but be OK at half throttle or so... just to much right thrust... you probably want 2 degrees or less right thrust. The climbing sounds ALMOST normal... under full power you'll likely climb unless you trim at full power... most trim out at half throttle so it's going to climb as you add power... lot's of down thrust can make this worse... it will also tend to drop as you reduce power if your trimmed at half throttle... having the down thrust keeps this from being to bad though.

Get out the book and GO OVER EVERYTHING... it's likely something in your set up.

John

RE: Strange Problem
 

Fred, I'm not an expert or nothing, but I 'm gonna take a shot... 1st check your TX and make all ATV setting are centered__ALL TRIMS are centered, lateral balance is acceptable( on a trainer nowadays,I fly it 1st then add weight to the wing if necessary on either panel)__CG is acceptable, not too much right thrust in engine mount__ sometimes on ARF's they overdo it, ailerons are moving freely,__also be sure they are flat w/ bottom of wing panel,also tork rods aren't binding,__make sure wing is centered on fuse__also not canted front or back on fuse, also vertical and horizontal stabs are mtg properly___Basically I taking you back thru the set-up and assy process...Also chx for any control rod flexing__ chx visually and manually by lightly grabbing the surface and moving the TX stick simultaneously__NOW if all this fails 1. You have a torquey engine which can be managed:D OR 2. you have a warped wing which depending on how bad can be fixed w/ your covering iron or heatgun. As a note when I built a cheapy ARF trainer once it had a wooden rail motor mount and like a ding-dong I put TOO much right thrust in it and the dang thing never flew right___ so I renditioned it..... HTH.....Rob

RE: Strange Problem
 

what radio?when i first had my futapa 8sga years ago,one of the mixing switches got bumped at the beginning of a pylon race and I could not turn,nor could i take my eyes off the plane to look at switches,had my caller look for me and luckily got it on the first try.you may have a setup/mixing turned on in the tx and not know it.if you simulate a turn on the ground with the engine off how do the controls respond,also how much dihedral is in the wing?

RE: Strange Problem
 

To much right off set in motor. When you turn left the motor turns upward and you climb but not turn turning right you pitch down. Torque on plane by your engine;)

RE: Strange Problem
 

Since a turn hs two components - bank/roll and pitch - which isn't working? What do you mean when you say "When I try to force it to turn..."? Is the plane banking left but then rising, or is it not banking? Can you get the plane to do a roll? Both directions? On ground check, are you getting equal deflection of the ailerons in both bank directions? Do you have suggested elevator and aileron throws?

RE: Strange Problem
 

thinking about this some more,are you using aileron differential,ie more up deflection than down,as the superstar uses a flat bottom airfoil which is susceptible to a reverse yaw with the use of ailerons

RE: Strange Problem
 

O.k. Guys
Let me try to answer your questions. The plane does not bank, It just wants to go straight up. The ailerons have the same deflection both ways. and all throws are what they call for in the book. I will not try to roll it because with my ability as a pilot, if it don't do what it is supposed to, I will need a new plane. That being said, If I measure from the end of the prop to the end of the tail, I get a shorter distance on the right side than on the left. ( If that makes any sense) This leads me to believe what many of you have said. That I have too much right thrust. So I am going to turn the motor to the left, and I will let you know what happens. The weather here stinks, so it might be a while before I can try it.
Thanks again
Fred

RE: Strange Problem
 

Another fellow here had a similar problem. More rubber bands to hold the wing down was the cure in his case.