Assembly of Nexa P-47 (1500mm) Balsa Thunderbolt by Papa Boozer

[eric h]

Planning maiden flight .
30 mm full flap is recommended in build book. Agree?
Any recommendation for elevator mix?

[Thimble]

Loving mine!

[Robinson Parker]

I’ve had this plane for almost two years and still have not been able to fly it. I went out to the shop to try and toy with it again but I’m stuck. My elevator servo is having a really hard time applying any pressure to the control surface. I’ve tried adjusting the servo positions and even replaced the elevator servo. I can’t figure out why the elevator push rods are so difficult to move, even by hand they’re relatively sticky feeling. Where did I mess this up? Can anyone shine some light on my problems 😂

[marty 72]

Robinson,

Let's start with what servo do you have in there? Second, just sliding the control rod by hand, how sticky is sticky? You are going to have to guess a load, 1/8, 1/4, 1/2 pound? Is it dragging equally through the range or just in one spot.

If it's the control rod is really tight, it might need a bend in it. You are going to have to do some more experimentation to find a way to free up the control rod. But first, let's look at the servo, perhaps it's just not powerful enough.

[Robinson Parker]

Robinson,

Let's start with what servo do you have in there? Second, just sliding the control rod by hand, how sticky is sticky? You are going to have to guess a load, 1/8, 1/4, 1/2 pound? Is it dragging equally through the range or just in one spot.

If it's the control rod is really tight, it might need a bend in it. You are going to have to do some more experimentation to find a way to free up the control rod. But first, let's look at the servo, perhaps it's just not powerful enough.

Here is a quick video showing what’s happening. For some idiotic reason it was actually semi-working but still not up to my standard. The elevator is too important of a control surface for “good enough”! Ha.

[marty 72]

Ok, the servo is fine, I'm familiar with it, it should work fine.

Is this your first warbird? You don't need much elevator throw for warbirds. check your manual for throws, but I'm thinking +/- 12 millimeters and you are well beyond that.

You also may want to move your easy connect coupler for the elevator. That could cause binding, it appears to be hitting the sleeving in the video (but again, I don't think you need that much movement).

Before you drive yourself crazy, just move the elevator the required throws. Disconnect the servo arm from the two control arms and operate the elevator (each side alone) by hand and see if you have binding. If that's good, then connect the two rods together and see what happens, if that passed move on to the servo arm, ect. Go back to basics and systematically solve the problem. Check one thing at a time, verify it works and then move on to the next level of complexity.

Your elevator hinges could also reduce your throws, it may not be drag in the control arms/sleeves. Just another thing to check.


Just my thoughts.