I know everyone will say "You have downthrust", I've told many others the same thing when they explain this symptom but when I chop the power on my Lanier Edge 540T it climbs, and I've already got about 1.5 degrees of upthrust in it. What else might be the cause? Has anyone else seen this on this ARF?


JJ

I dont know what plane but usually down thrust and right thrust are common. It could be tail heavy, would explain the climb when chopping the throttle or the wing incedence could be off...check the incedence with a meter...if thats ok then check the cg...you will probably find that you will need to put a little down thrust back in. You can check the motor thrust with the incedence meter also. good luck!

Ron

I have an Aeroworks 540T ARF that does the same thing. I have been in this hobby a very long time and owned a lot of airplanes but this one stumps me. I have messed with this rascal quite a bit and it's about as close to a perfect setup as you can get and it still does it. If your radio will handle it you can mix in a little bit of down elevator at low throttle to get rid of it but it frustrates me that I can't figure it out. The plane flies great so I finally said the hell with it and just go have fun with it.

JLB, we have 3 of the Aeroworks Edge ARF's at my field and they are all set up wrong (severe balloning on final while chopping the throttle). We added about 2* (1/8" under the 2 bottom engine mounting bolts) of up thrust and the airplane finally flew like it should. Tthere is so much down thrust in all 3 from the factory, that when you would roll the plane inverted at 1/2 throttle and go to full throttle, it would climb.....Shim 1/8" under the 2 bottom engine bolts and the pitch changes will go away....Aeroworks dropped the ball on this one..........

On my 33% Aeroworks Extra 330L I was experiencing the tail dropping when I cut the throttle. I moved the batteries forward about a foot and now it's fine!



Dale Randles

2* upthrust worked on the Aeroworks Edge eh? I know that my cg is actually at the "Noseheavy" end of the range for my Lanier. I checked relative incidence (don't have any datum) on the surfaces and firewall before I glued the stab last year. I don't remember what I came up with, but they were reasonably decent. Flew it once last year and it ballooned, so I put a little less than 2* (I do mean positive, above zero),upthrust in the mount. Got my first chance to fly it again this year and it still balloons quite a bit. I just ordered a new incidence meter today, and we'll check this out again before the weekend. I'd be surprised if the correction would be 3* of upthrust, that would be strange. I guess I could mix it out, but that would get tough in other areas, knifedge, spin entry etc

Thanx guy's

JJ

Most ballooning airplanes that I've seen are caused by being tailheavy. Although every owner swore up and down that the plane was nose heavy.........right.

Fly it inverted straight and level....chop power. Now where does it go? If it heads for the clouds, then it's tail heavy.

Hey fellows looka here I have a DP Extra that had the same problem. This was a porpoising fool trying to land,at half throttle it flew nice and trim. Inverted required no trim change. But when the throttle was cut it would gain altitude just like a glider in a nice breeze. After looking at and reading every thing I could I found an old article form DP himself about the GB Ultimate and why the stabilizer had 1 degree of positive incidence built in. The lite wing loading and high lift created caused the planes to climb at fast speeds. Then when some down thrust is added and speed increases the engine pulls the plane down, then you need a little up elevator to counter the engine thrust. So when the throttle is cut after it is trimmed at speed it starts to climb since the engine is now not pulling it down. Luckily the stab on the DP Extra is adjustable , It is at 2 degrees positive ( up in the front) the engine is now at 1 degree down and the plane flies great. Now I have to hold back on the elevator to land.
So either adjust your stab or rip it out and make it adjustable.

Hope this helps Kent

The engine is offset from the thrust line of the airplane...

OK, I got a chance to check out my Edge with my Laser incidence meter. I set my meter to zero on the surface of the coffee table, set the plane up on the coffee table and spaced up the tail with DVD movies until the stab was exactly 0 degrees (left and right equal w/elevator neutral), checked left and right wings (Ailerons neutral , left=.25 degree positive, right wing .5 degree positive, mounted meter squarely to spinner backplate as it was designed for .25 degree upthrust. I guess the 1.5 degrees + thrust I added only brought it to around 0. V-snap, I took a look down the "Eyeballed" thrustline while the stab was at 0, and it does look like the engine crank line is offset up about 1 inch or so. The way I've set CG is at the noseheavy side of the range specified in the manual, and many other guys with the exact same ARF have theirs set way aft (more than 1.5 inches back from mine). I do know one guy who said he had to add upthrust but had no idea how much. I guess I'll have to put in a degree at a time until it the problem goes away. This just seems wrong, but what do I know. What do you guys think now that I've posted all my measurements?


JJ