• If You Are Having Trouble Logging In with Your Old Username and Password, Please use this Forgot Your Password link to get re-established.
  • Hey! Be sure to login or register!

Stearman spar splice

bob turner

Registered User
Yep. Spring project. John Pike, of Big Sky, has been quite helpful. I am just about ready to start cutting - it is the rear spar, and it is cracked right at the N-strut attach point.

I am assuming that I will have to cut, then re-splice, two ribs in the bay just inboard, to get the proper 43-13 splice distances for the scarf and plates. I have done a wood spar Cub splice, but that now seems trivial in comparison.

Happy to get suggestions here - there appears to be more aviation knowledge on this forum than on all the others combined. SRA was only marginally helpful - I learned only that the 43-13 drawing came from Boeing.

If I screw it up, no big deal. The airplane is flying with a new wing.
 
Yep. Spring project. John Pike, of Big Sky, has been quite helpful. I am just about ready to start cutting - it is the rear spar, and it is cracked right at the N-strut attach point.
Remember a fitting can't be in the splice location.
 
I have 20” between the fitting and an inboard reinforcement plate for the aileron push rod. Not enough room for the 43.13 splice plus plates. A fitting can go over a plate, but not this fitting, since it is an aileron hangar bolted to the N- strut and a compression strut.

Puzzling that I cannot get any info on this - the Stearman lower wing takes a beating, and any time a spar breaks, it surely breaks right where this one did.
 
Is there a Stearman Structural repair manual from either the Army PT-13/PT-17or Navy N2S? If so, you can use the data there rather than 43.13-1a.


Sent from my iPhone using Tapatalk
 
Thanks. Excerpts from that manual have helped before, but the one stored on the SRA website is less than helpful. The Army manual might be better. The aircraft is an A75N1 I think.

Here’s hoping Boeing had a way of fixing this. Be a shame to have to cut it up and start over, although probably very educational.
 
I spliced a spar on a J3 ten yrs ago….I worked great. That resorcinol glue is effective. I’m sure there are modern adhesives that would work well (or better) but 43.13 says what to use and how to do it.
 
I found it! The “Overhaul” manual shows a splice that fits, and allows it in the exact area I had targeted. Now it is just a question of getting a router setup that is bulletproof.

This should be “satisfying.”
 
Back
Top