News:


  • March 28, 2024, 05:21:21 PM

Login with username, password and session length

Author Topic: foam wing advice  (Read 2261 times)

Tom Vieira

  • Guest
  • Trade Count: (0)
foam wing advice
« on: August 06, 2018, 06:23:10 AM »
Hi all,

I'm building a Gotcha Streak RST from Core House, and I put the wing together last night, no issues, I thought...

Went down this morning, and apparently it shifted a little, and what looked like a nice tight joint at the leading edgehas opened about 1/8 inch, and the Titebond I was using for its assembly ran out.

I do have extra cores, but would rather save this if possible.  just wrap the center joint with some fiberglass and call it a day?

Offline Jim Mynes

  • Trade Count: (0)
  • Commander
  • ****
  • Posts: 321
  • Chelsea, ME
Re: foam wing advice
« Reply #1 on: August 06, 2018, 07:37:03 AM »
Fill the gap with epoxy/microballoon mix, then use the same mix to glue some reinforcing glass cloth to the wing joint. Squeegee off as much glue as you can to save weight.
I have seen the light, and it’s powered by a lipo.

Tom Vieira

  • Guest
  • Trade Count: (0)
Re: foam wing advice
« Reply #2 on: August 06, 2018, 09:15:13 AM »
cool, thanks!

Online Brett Buck

  • Trade Count: (0)
  • Admiral
  • ******
  • Posts: 13717
Re: foam wing advice
« Reply #3 on: August 06, 2018, 09:16:49 AM »
Hi all,

I'm building a Gotcha Streak RST from Core House, and I put the wing together last night, no issues, I thought...

Went down this morning, and apparently it shifted a little, and what looked like a nice tight joint at the leading edgehas opened about 1/8 inch, and the Titebond I was using for its assembly ran out.

I do have extra cores, but would rather save this if possible.  just wrap the center joint with some fiberglass and call it a day?

    I would be sorely tempted to cut out the glue, square it up, and then try again.

      Brett

Tom Vieira

  • Guest
  • Trade Count: (0)
Re: foam wing advice
« Reply #4 on: August 06, 2018, 09:24:07 AM »
Brett,

tough to do with the top and bottom spars glued in...

Offline Mike Haverly

  • Trade Count: (0)
  • Captain
  • *****
  • Posts: 844
Re: foam wing advice
« Reply #5 on: August 06, 2018, 10:22:01 AM »
If you ignore the problem it won't go away.  If you have trouble making fly the way you want, you will always wonder.  I would fix it before it is complete. 
Just my opinion of course, but I have experience in the "ignoring" part.
Mike

Offline john e. holliday

  • 24 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 22752
Re: foam wing advice
« Reply #6 on: August 06, 2018, 10:44:27 AM »
I too had a problem with Core House foam core having a gap either leading edge or trailing .  Checked wing and it was straight,  Filled gap with filler and finished the wing according to instructions and had no problems with the planes not flying right.   D>K
John E. "DOC" Holliday
10421 West 56th Terrace
Shawnee, KANSAS  66203
AMA 23530  Have fun as I have and I am still breaking a record.

Tom Vieira

  • Guest
  • Trade Count: (0)
Re: foam wing advice
« Reply #7 on: August 06, 2018, 11:17:57 AM »
the first time I was dry fitting things, there was a huge gap in the back, but the LE was straight.  understandable, as it's cut out of a big block, and no guarantee that was straight.  so, I measured and cut...

looked pretty good, so I propped it up, but I must've biffed it somehow, thus the small gap.  it looks tight from the spar back, but the spar fwd it a little wonkey.  a few quick checks (I noticed it this morning while getting ready for work), and it looks straight and such, just this annoying gap.  I also tried to flex the wing, I couldn't make it spread.

I think a 2" wide strip and some epoxy may be in my future....

Offline Tim Wescott

  • 2016 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 12804
Re: foam wing advice
« Reply #8 on: August 06, 2018, 12:04:14 PM »
I built a couple of trainers using the Gotcha Streak wing cores.  I started with epoxy + microballoons, but have moved to using clear Gorilla Glue.  It's lighter, and much closer to the strength properties of the foam, so you don't re-fracture the wing right where the glue joint is, and you don't add much weight.  I've even been using it to fill holes when there's chunks missing after I gather up the pieces and glue the wing back together.  Just don't use it for wood to wood joints.

Spritz water in the hole, inject some glue, poke it in with a stick, then wait.  When it's solid (about an hour or two) take a sharp wood chisel* or a single-edge razor blade and carve off the excess.  Then proceed.

* Really sharp, not from-the-store sharp
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Offline Fredvon4

  • 23 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 2099
  • Central Texas
Re: foam wing advice
« Reply #9 on: August 06, 2018, 12:35:34 PM »
Gotcha streak and RST are pretty much same.... Narrow Bass wood fuselage and 1/64th 1 inch wide by 23 inches long glued inside of wing cut out...The bell crank is under the wing attached to the Fuselage

I have two that I Use Gorilla tape to hold the wing in the fuselage....quite frankly this is about the easiest stuntable plane to make alignment on

The wing basically is warp free... NO flaps
Tail fathers are keyed and not hard to get Zero Zero on all planes
Skewing the wing and alignment are easy with shims, and once taped or glued, it is level level level to the thrust line and tail

Problem for OP is did the wing shift out of good alignment...Epoxy is easy to soften and with heat gun..BUT NOT on a FOAM wing!!! and because of the 1 inch wide 1.64th opening the wing is in....NOT a whole lot an be done without major surgery

I say fly the sucker...have fun and build another...I have three...about the best bang for the buck semi ARF there is

"A good scare teaches more than good advice"

Fred von Gortler IV

Offline Will Hinton

  • 24 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 2765
    • www.authorwillhinton.com
Re: foam wing advice
« Reply #10 on: August 06, 2018, 08:44:52 PM »
Ahh Fred my friend, I have softened epoxy in a foam wing with no adverse effects.  Just don't plaster the gun down on the wing but pass it back and forth slowly until the epoxy softens up and give it a twist to staright, or seperate it if that's your goal.
John 5:24   www.fcmodelers.com

Tom Vieira

  • Guest
  • Trade Count: (0)
Re: foam wing advice
« Reply #11 on: August 07, 2018, 06:03:04 AM »
I'm sure this thing will see the dirt soon enough...  I took another look last night at the wing, and it all still looks pretty freaking straight and true.  I'm wondering if I didn't pay close enough attention to the spars, and one or both had an ever so slight curve that pulled it just enough to make a gap.

I think i'll wrap it and go nuts.  the wing will be taped in, not glued.  so, if it proves to just be a flying pile, I have extra cores.

or, I'm also building a second one at the same time for my nephew. something a little more sturdy than the 1/2a jobs.  His will probably smack the ground quicker.  Perhaps just make this wing his  LL~

Offline phil c

  • 21 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 2480
Re: foam wing advice
« Reply #12 on: September 09, 2018, 05:18:38 PM »
I'm sure this thing will see the dirt soon enough...  I took another look last night at the wing, and it all still looks pretty freaking straight and true.  I'm wondering if I didn't pay close enough attention to the spars, and one or both had an ever so slight curve that pulled it just enough to make a gap.

I think i'll wrap it and go nuts.  the wing will be taped in, not glued.  so, if it proves to just be a flying pile, I have extra cores.

or, I'm also building a second one at the same time for my nephew. something a little more sturdy than the 1/2a jobs.  His will probably smack the ground quicker.  Perhaps just make this wing his  LL~

Really TJ you can just fill the slot with some light weight filler and proceed.  That portion of the wing has no real structural or alignment function that a little vertical gap is going to mess up

As FredVon4 points out, the ply saddle for the wing provides a ton of strength for the wing/fuse joint, and makes it easy to shim into alignment with the rest of the plane.
phil Cartier

Tom Vieira

  • Guest
  • Trade Count: (0)
Re: foam wing advice
« Reply #13 on: September 19, 2018, 11:41:57 AM »
Hi phil,

both planes I have built are flying great!  even trying a few new moves now ;)


Advertise Here
Tags:
 


Advertise Here