Scale Wendell Hostetler 30% PA-28 Cherokee Build

[AKNick]

https://www.flitetest.com/articles/rotary-drive-system-for-aerilons-or-flaps

Thanks for sharing that. Very Interesting. I'm curious how much torque something like that can handle. Seems like it would be relying a lot on the mechanical integrity of the bend radius, G10, and Allen grub-hub screw especially.

 

[TonyHallo]

Using this https://www.servocity.com/4001-seri...ft-coupler-25-tooth-spline-to-6mm-round-bore/ from ServoCity, 3/32" music wire and the slider box is epoxied into the foam and balsa. This setup is a little more robust than what is shown in the video. I used similar couplers on the original Cherokee that were maintenance free for 7 years driven by Hitec HS7995 servos at 6 volts.. The RDS kit sold by ServoCity is light weight.
It will make more sense once completed. Here is a photos from the original build, this was untouched for 7 years of flying on a regular basis.

 

[TonyHallo]

Clamped the vertical fin in the mill and cut the servo pocket. this will get a 1/32" plywood floor

 

[Stevendavis]

That's a great way to do that!! I still have to use a razor knife on foam.

 

[TonyHallo]

Here's the nearly completed RDS. Waiting for the coupler from ServoCity. The servo (HS5955) and coupler shown are from the original Cherokee, this one will get a new D945TW servo with 25T spline. The hatch is also installed.

 

[dhal22]

Gawd I love hidden servos. Nothing WORSE than years and years of scale construction details RUINED by a loud 2 stroke engine and visible control rods and servos everywhere.

Rant over, back to Tony's excellent work.

 

[TonyHallo]

Thank you David, started laying out the wings on the bench, have everything laid out and tomorrow I hope to cut the foam blanks and start cutting templates. This will be the first foam rib wing that I have built that is not a symmetrical airfoil so I trying some new things. Since the wings have 7 degrees of dihedral it's going to take a lot of foam. Have a 4x8x1/2" sheet of foam in the van along with 4x8x1/4" underlayment that will be used plus some foam I have left over from previous projects. The flaps will have hidden linkage and thinking that the ailerons will get RDS as well.

 

[TonyHallo]

Got the inner four rib blanks for both wings jigged in place. The next step is to cut the wing tube holes in these blanks then finish installing the remaining blanks. The blanks are held in place with wood parting strips brad nailed to the bench, friction is holding the blanks. The inner most ribs are 1 1/2" thick, the remainder are 1/2" nominal but measure 5/8"? The purpose of the thicker inner rib is to allow the wings to be coped to the fuselage. I had installed short stub ribs on the fuselage and had planned to make the inner rib straight but someone revised the plans! Maybe a mistake? No just a revision! Going to lunch with several old workmates so this ends today's session. The two strips of foam on the top are holding the blanks square.

 

[TonyHallo]

The wing tube holes are cut on both wing at the same time. Templates are drilled together to ensure the same height, a cap is added to prevent the wire from hitting the entry slot while cutting. The tube slides right through. Next up cut the leading and trailing edges straight and add foam sheeting to each. This allows for gluing the sheeting at the edges. Will also add 1/4" plywood top the the rib blanks to keep everything in place after the top is cut. This will allow for work on the bottom of the wing. On a symmetrical airfoil once the bottom is cut the wings are flipped over and rest on the opposite rib blanks. Can't do that here. It's coming along nicely, I'm at the 2 month mark today.

 

[BalsaDust]

Nice work so far.