Hi all,

I am working on my new design of pattern plane, this time the wings are bit different i have attached the picture. I am planning to go with a foam wing, but the problem is the wing has a thin tip. Can anyone suggest me how should i cut the cores i mean should i built each wing in 2 parts with different aerofoil & then join it together or what would be better.

Thanks in advance,
Harry

I would cut the cores in two sections, glue a 1/16" cap on the root core, sand to match the core airfoil and then glue on the tip core. Fit your sheeting and then vacuum bag the sheeting in place outside the shucks.

I have been researching building foam wings - I have a set of cores I am going to build.

I am wondering if you can cut with one airfoil, but use different sized stock for the leading edge and sand appropriately?

Separate pieces is certainly an option, there are threads where people cut single airfoils in parts to install the ribs.

I am curious what you mean about having a 'thin tip'.

DEFINITELY read over Isaac Najary's build threads - he doesn't cut or sheet the foam, but there is a lot to be learned about installing the edges, tips, and sanding, etc.

Looks like fun! Enjoy!!

You can do it in one piece with a bow cutter(S), but you need to build a jigg rail for the outter tip part of the wing and a set of extended false ribs. You cut the wing first then go back and do the tip area seperately. I am using these style of wings on the design I started back in 2009 (not finished yet, fuse is built up). I also plan to use these on my Black Magic VF3 E.

You can cut these in two sections also, but be very careful to get the halves matched up in the shucks, taped and glued with Gorilla glue and weighted well. Don't forget to line the shucks inside with wax paper. David Snow has a wooden set you can order based off the wings from the Spark (blog on them).


Good Luck!

bholsten

The other option for me is rather than cutting two separate wing cores, i will cut the wing in one piece & later after sheeting i will cut the slot as shown in the drawing rather than using two separate aerofoils and later gluing them together.

I personally would not do it after the sheeting is on, because it will give you a larger leading edge piece to deal with out on the tip. However, no harm in giving that a try, don't think it will yield the results your looking for in fast snapping wings.


bholsten

If you want this aircraft to perform, the wing must be 100% accurate. I suggest that you contact the BEST and MOST EXPERIENCED foam wing cutter on the planet- BOB HUNT !
Bob's Ukie Stunt resume is extensive (also was an excellent Pattern flyer awhile back). Former editor of Flying Models and Model Aviation Mags.
Reach him @ Robin's View Productions( 610-746-0106). His shop is an easy interstate drive from NYC- about 1 1/2 drive in Stockertown, Pa.
Tell him I sent you.

Sorry, i am not in NY my brother is in NY. I am very far from that. But yes now i have finally decided i will build the wings in 2 separate core as i mentioned earlier & then join them together as the aerofoil is thin at the tip. I am good at cutting cores so this will not be a problem, the only thing was i am building this type of wing for the first time.

Thanks for all your help will keep you updated on this.

I suggest cutting the foam blank according to the desired overall planform and then drawing a centerline all the way around the perimeter. Then cut the blank into three pieces- trialing edge full span plus an inboard and outboard leading edge blanks and add the centerlines. Then hotwire all three blanks to desired airfoil. You can then easily include a spar between leading and trailing sections and probably should as you have lost the integrity of the LE and some of the sheeting across the airfoil discontinuity. If you cut well on the foam blank centerlines, then you should be able to assemble a core and shucks that are compatible for skinning. Slice the skin at the discontinuity and skin the way you would normally.
Hope that makes sense.
John