Form blocks for the tail

[Cameron Ramsey]

I need help builders. Im wanting to make my form blocks for my horz. And vertical stab. And I don’t understand my plans. Could anyone clear this up for me? Bob gives a location for the max airfoil thickness and a location on the example on the plans. I know this measurement will change with the length of the rib. Are the plans saying that the max thickness of the camber is 1/3 back from the nose of the rib? If so, what is the .09 number for? I’ll attach pictures to help explain. Also, Bob forgot to fill in what pages to the drawings are on to scale from but im pretty sure its the pages that have the stabs. on them.

[rodsmith]

Yes the max thickness is located at 1/3 of each ribs chord back from the leading edge. Multiply the width of the stabilizer (x) at each rib location x .09 to get the max thickness of each rib. I don't have the airfoil shaped ribs but I just added the wood strips to give the airfoil shape and the numbers work out the same.

[Cameron Ramsey]

That helps tremendously Rod! Thank you. I may draw up my templates today. Yea!

[Bdflies]

Just one more reason that I have tremendous respect for anyone that completes a plans built aircraft!

Bill

[way_up_north]

Bob should offer these for sale on a separate Mylar sheet.... when you buy your plans... I’d gladly pay for the correct shape pre made

[Cameron Ramsey]

I got mine made for the horizontal stab. thanks to Rod helping me to understand what the plans were saying. It’s like anything else. It seems hard until you understand it. You do have to have your master form block made to use the bottom of the airfoil for the shape though. I actually enjoyed doing it.

[Gr8apmech]

Did you use .025 material or .032 material for these? Drawing 24b shows .025 but the T-25 is called out to be .032

also, did your form block include a undercut to allow a 1/4” bend on the edges to protect the fabric?
thanks!

[alaskabearhawk]

This might help...

https://www.youtube.com/watch?v=rUyTOwfnQiI&t=2s

https://www.youtube.com/watch?v=xklhaKkfCzk&t=57s

https://www.youtube.com/watch?v=GhuhLJXEWr8&t=7s

[Gr8apmech]

One down! Thanks guys. I’ve watched those a few years ago. Got them back on my playlist.