Your expert second opinion is requested to see if I am on the right track. I just built a giant spad profile with a Ryobi gasser on her. Pictures are in the spad forum. Anyway I wanted to compare the way I set it up with some of the profiles here on RCU.

On the test flight she would climb with throttle, so as to require down trim. Of course when you go to land and throttle back she drops her nose due to the down trim.

I had some slight droop in the ailerons and if I compare it to planes like the something extra they seem to have the ailerons with a slight up to them. Are some of your profiles set up the same. I was also thinking that some down thrust in the engine might be required. Does your profiles have down thrust?. Just looking for some comparison.

My setup has 0 down or up thrust. Slight right thrust. The wing and horizontal tail feathers are all in line with the thrust line and 0 deg. of incidence.

Thanks in advance folks.

Peter

If I had a model which climbed with throttle-up, dropped with throttle-back, I would add down-thrust to the engine. If you have a computer TX you can mix throttle-to-elevator to avoid having to re-mount the engine; set it so as you add throttle you slave elevator down a few percent, starting with maybe 3-4%. Just watch out for nose-overs on take-off until you get it right.

What's the reason for drooping the ailerons? Is this on both wings? Do you have a flaperons mix active on your TX?

In my limited experience with bipes I have seen arguments & recommendations for decalage in the wings--lower wing neutral, upper wing one degree negative, or something like that. Some such arrangement would probably help your pitch-to-throttle coupling, but I'm not the expert on that.

Thanks Majortom;

The slight droop on both ailerons was done inadvertantly, or could have bumped the nob on the transmitter. Since I can control the flex of both ailerons on the transmitter for flapperons etc. I'll probably start there.

The coupling idea might be another idea If all else fails........ good plan, thanks. I should have a chance to experiment more this weekend... I hope.

Thanks Peter

Just put a washer or two behind the top of the engine mount. That should give you 1 or 2 degrees downthrust. Easy fix. Shouldn't take more than 10 minutes.

Thanks Rcpilet;

Yea, not a big thing to give some downthrust. I was more curious with the aileron flex. If the ailerons were flexed down, in theory they should act like flaps and give alot of lift with a large throttle output. Now if that was what is wrong, could be a whole different story and if the 3/16 or so of droop I had would make a difference.

Oh well, hope to find out this weekend.


Peter

my .40 size ultimate profile dives if i put the flaperons on. even a little. set the ailerons level and see what it does.

Just for grins.....why not set your ailerons where they are supposed to be (in-line with the center line of the wing chord)...? If you want flaps or its effects - why not just add flaperons to the mix.....?

Adding down thrust to your engine would be a good place to start to counter act the plane wanting to climb at higher throtte levels and then go from there. It's kind of a process of elimination........

Good luck!

Thanks everyone;

I set the ailerons with a slight up flex and it solved everything. I know some other factory planes are like this, like my something extra. Thanks again.

Peter

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looks nice. i'm going to try that with my bipe too.