Piper Cherokee ( nearly)

That looks really smart crash! you've got a lovely finish on it, some of the foamys I see up my strip are frankly shit! ( sorry for language mods...) I sometimes look at them and wonder how they've managed to get them so bad..

Thanks Paul. The only reason I can get a decent finish is because the foam is covered. Uncovered EPO foam is a nightmare to paint ! ( see painting foamies).

paul d wrote: That looks really smart crash! you've got a lovely finish on it, some of the foamies I see up my strip are frankly shit! ( sorry for language mods...) I sometimes look at them and wonder how they've managed to get them so bad..

Language allowed on the grounds that it's an apt description.

Ta Klippy, next time I'm up there I'll try to sneak a few pics, There's one in particular that's so hideously awful as to be funny.

After a reasonably good test flight ( details can be found in "been flying") I started on some more mods to the Cherokee. The whole nose section has been strengthened internally & a new wooden firewall made. The firewall is now recessed into the nose & deigned to spread the load on the nose wheel through the whole structure. Everything was glued with epoxy & filled lightly around the rough bits. Sanding, painting & fitting the motor tomorrow when everything has dried.

For the next flight try putting a 2mm wedge between the TE and the fuselage, keep increasing between flights until your elevator trim for straight and level, half throttle is neutral, then re-do your wing fairings to compensate, it's much easier than remounting the tailplane!

Klipkopwildlife wrote: For the next flight try putting a 2mm wedge between the TE and the fuselage, keep increasing between flights until your elevator trim for straight and level, half throttle is neutral, then re-do your wing fairings to compensate, it's much easier than remounting the tailplane!

I get what your saying (I think) Klippy, but shouldn't I try it with the CG moved back to 28% first as it was definitely nose heavy ?

crash happy wrote: it was definitely nose heavy ?

Is it flying with a 'tail down' attitude?

Crash, the moving of the CoG will improve the flying but it won't change the amount of trim needed by very much. 1^o of Decalage is not enough with a Clark Y 2^o is recommended. I said nothing at the time because I wanted you to have a flyable aircraft without doing too much work, now we're fine tuning, from what you've said you'll end up with a very nice flying low winger.
OF, tail attitude hasn't been mentioned as yet, and in any event is in the eye of the beholder. Crash used every bit of up trim, and then some to maintain level flight. We can attack that problem later.

Klipkopwildlife wrote: Crash, the moving of the CoG will improve the flying but it won't change the amount of trim needed by very much. 1^o of Decalage is not enough with a Clark Y 2^o is recommended. I said nothing at the time because I wanted you to have a flyable aircraft without doing too much work, now we're fine tuning, from what you've said you'll end up with a very nice flying low winger.
OF, tail attitude hasn't been mentioned as yet, and in any event is in the eye of the beholder. Crash used every bit of up trim, and then some to maintain level flight. We can attack that problem later.

Just going to run this by you Klippy so we are reading off the same page & I fully understand It.
We are aiming for level flight without trimming (or very little) at a set airspeed, in this case half throttle? During the test flight it took of at WOT & climbed steadily at about 35 - 40 degrees (can't be precise) but with full elevator & the CG at somewhere between 23-25%. Not wanting it to get to far away I turned onto the cross wind leg at about 40ft trimming in up elevator & reducing to half throttle. It was from this point until landing that I had to use a lot of elevator to stay level, hence the nose first landing.
Increasing the angle of incidence to 2 degrees will be easy, just take some of the shims out. The empanage however is glued in pretty fast. I did take a lot of time to be sure that the H stab was parallel to the fuselage center line. All that being said will it be okay to move the CG to 28% & the angle of incidence to 2 degrees & try it like that ?

We're on the same page, you don't need to do anything with the empenage, just increase the angle of attack of the main wing to about 2^o and bring the CoG back to around 30% for starters.

Mod's now complete. Beefing up the nose & fire wall added some weight but as I already had 30 grams of led in the nose it was not a problem & this has now been reduced to 10 grams. There is also enough room to move the battery back & forth for balance. The wing is marked at 60 & 65 mm from the leading edge, giving me a CG range of 28.5 to 31% Wing incidence is now 2 degrees.
Now it's just a question of waiting for the weather gods to play ball for the next test flight.

Why are you using a Glow prop and not an electric one? They're so much more efficient and better balanced.

And a long prop adaptor too!
Its an out runner which means the prop, and any out of balance forces, are now a long way ahead of the front bearing.
In engineering terms shafts 'over hung' beyond the bearing are never ideal. In this case the motor bearings will be seeing loads multiplied several times compared to the same loads if the front bearing was close behind the prop. Just saying.

Okay, I understand both your points. The simple answer is they are donor parts from another model. The prop is the one recommended & is supposed to be for electric, I bought ten of them & so far they have needed very little balancing, three are in use. The prop adaptor is as fitted on the model it came from, Stefan's old Apprentice. We have both been flying these planes since the spring & touch wood have had no problems with the motors. Still appreciate the advice though.