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Building Tips and technical articles. => Building techniques => Topic started by: joe renfro on November 30, 2007, 07:11:46 PM

Title: Bellcranks in Foam Wings....???
Post by: joe renfro on November 30, 2007, 07:11:46 PM
I know this has probably been addressed somewhere over time, but for an old time new comer...how does one insrall the bellcrank into a foam wing and the leadouts and pushrod...? Seems like you would have to cut the wing to smithreens...Anxiously waiting to hear how its done..

thanks in advance...
Title: One box that does three things..
Post by: Paul Smith on December 01, 2007, 07:46:25 AM
My solution was to build box beam of balsa, spruce, and plywood contruciton.  It does tree tings,

1. Bellcrank mount,

2. Landing ger mount,

3. Splice the right & left wings.

All it takes is one simple slot to fit it in.  It weighs a couple ounces, but it's comparable to the many bits it replaces.  More important, I have confidence that it will work, which is the only thing that counts.

The second pitcher is a one-time fixture to cut the slots.
Title: Re: Bellcranks in Foam Wings....???
Post by: Crist Rigotti on December 01, 2007, 10:41:25 AM
Use a "post" mounted bellcrank.
Title: Re: Bellcranks in Foam Wings....???
Post by: Steve Helmick on December 01, 2007, 06:28:35 PM
Note that Crist is "The Controline Guy", and his product IS foam wing cores. See the Vendor's Forums below. His method is the "industry standard" and has been done thataway for many years. Not that Paul's method won't work... H^^ Steve
Title: Re: Bellcranks in Foam Wings....???
Post by: Bill Little on December 02, 2007, 10:25:51 AM
I have always done like Crist shows.  It is important to mention that ply caps go around the rod once the wing is finished.  I make the caps to fit the inside edge of the fuselage.  Then I place a square (epoxied) piece of ply over the top and bottom ends of the rod.  This will distribute the pull test loads to more surface area.
Title: Re: Bellcranks in Foam Wings....???
Post by: Greg L Bahrman on December 02, 2007, 12:03:48 PM
As Bill says. Install a small ply plate both top and bottom of the wing also. The bellcrank pivot rod will go thru the plates and then get trimmed off. The plate will glue flat to the wing and fit between the fuse sides. My spar is plywood with .010 thk. clear G10 fiberglass sheet laminated on both sides for added strength. I also fiberglassed the center section top and bottom with 1/2 oz. cloth after sheeting.   n~