News:



  • March 28, 2024, 11:33:02 PM

Login with username, password and session length

Author Topic: Bellcrank Mount  (Read 1034 times)

Offline Casey

  • Trade Count: (0)
  • Lieutenant
  • ***
  • Posts: 85
Bellcrank Mount
« on: October 23, 2016, 09:18:13 AM »
Hi Everyone

I am puzzled by this plan. As I see it, the bellcrank rod which is 1/8 is mounted right through the 1/8 lite ply main spar. Since the bellcrank rod and the lite ply main spar are of the same thickness, does it mean that the lite ply main spar is not one piece and that the joiner spar not only strengthens the wing joint but also holds together the lite ply main spar together with the 1/16 ply cover plate

Offline Fredvon4

  • 23 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 2099
  • Central Texas
Re: Bellcrank Mount
« Reply #1 on: October 23, 2016, 09:33:58 AM »
I see it as a three piece main spar.    2 parts 1/8th Lite ply and a 1/8th Birch ply joiner...not sure about the orientation of the 1/16th cover plate

or if the void for the BC is already cut, or needs to be cut in after assy of the spar

also looks like the 1/8 BC pivot is captured top and bottom assuming ply pieces
"A good scare teaches more than good advice"

Fred von Gortler IV

Offline EddyR

  • Trade Count: (0)
  • Admiral
  • ******
  • Posts: 2562
Re: Bellcrank Mount
« Reply #2 on: October 23, 2016, 09:51:10 AM »
Since that is a foam wing the ply spar is in two pieces and then joined at the center with the overlapping pieces. The hole is whatever size is needed. I beam wings are done the same way but having a balsa spar not plywood.
Ed
Locust NC 40 miles from the Huntersville field

Offline Randy Cuberly

  • 21 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 3674
Re: Bellcrank Mount
« Reply #3 on: October 23, 2016, 11:27:06 AM »
I think it would be extremely difficult to assemble that the way the plan shows.  The more normal way to assemble a foam wing is to place the lite ply spars into the foam cores before sheeting the wing.  Since the foam cores are sheeted while still in two halves I can't imagine having all that hardware in place when sheeting the inner half and placing it back in the foam shells for curing.
The more normal way to do it is to install the lite ply spars and landing gear "clips" into the foam then sheet the foam cores and place them back into the shells and weight them down for curing.  After the cores are sheeted a notch is cut along the inner spar both top and bottom and the bellcrank pivot rod is inserted into the notch and epoxied onto the spar with the rod extending on both sides of the wing with the flap pushrod in place after the necessary clearances for it are cut into both wing halves.   The wing is then glued together at the center while in the outer shell bottoms and weighted down into the bottoms for curing to insure good alignment of the two halves.  After the wing is installed into the fuselage, plywood pieces are installed on the top and bottom of the wing against the fuselage sides.  These plywood pieces have holes drilled to capture the ends of the bellcrank rod and are epoxied to the wing, fuselage, and bellcrank pivot rod.  Then the entire center section inside the fuselage is covered with 2 oz fiberglass cloth and epoxy.  

Another safety feature that I incorporate is to dremel the ends of the pivot rod flush with the plywood supports and epoxy a plywood cap over the ends of the pivot rod to prevent any possibility of the pivot rod moving vertically.  This of course is done prior to covering the center section with fiberglass cloth.

I would also mention that if you were to buy sheeted foam cores from Bob Hunt or another supplier it would definitely be necessary to follow the above procedure (or a similar one) because they would be already sheeted with the spars installed.

Randy Cuberly      
Randy Cuberly
Tucson, AZ

Online Brett Buck

  • Trade Count: (0)
  • Admiral
  • ******
  • Posts: 13717
Re: Bellcrank Mount
« Reply #4 on: October 23, 2016, 11:27:43 AM »
Hi Everyone

I am puzzled by this plan. As I see it, the bellcrank rod which is 1/8 is mounted right through the 1/8 lite ply main spar. Since the bellcrank rod and the lite ply main spar are of the same thickness, does it mean that the lite ply main spar is not one piece and that the joiner spar not only strengthens the wing joint but also holds together the lite ply main spar together with the 1/16 ply cover plate

    The 1/16 ply "cover plates" are much stronger than the lite ply.

      Brett


Advertise Here
Tags:
 


Advertise Here