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Fuselage measurements and dimensions drawing?

29 posts in this topic

Posted

Maybe a touch off topic, but I always had a bit of concern over the more concentrated load of the Grove attachment points vice the more spreadout original gear (or aftermarket like the Highwing).

I know we have seen a few collapses with the Grove gear, but have the traditional (with wider gear mounts) been just as prone?

 

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Posted (edited)

Larry,

I cant prove it, but IMO the light longerons used to build a 500+ empty weight plane instead of a 700+ plane are a large part of the problem - ask any engineer about the bending strength of the 1/2" - 5/8" .035 wall tubing compared to the 7/8" - 1" diameter longerons on the Pipers.

I made mine larger from lower strut fitting to firewall, and added some more structural strength for my modified Grove mounts, which are not directly on the longerons.  This, by itself, probably didn't add more than 10 pounds to the weight of the fuselage.  I think my KF 5-7 Grove spring gear weighs about 37 pounds, not counting wheels, tires, brakes.

EDMO

Edited by EDMO

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Posted

I'm starting to get everything squared up.  The 1/2" tubing is .035" wall correct?  Is there any benefit to using tubing with a thicker wall where the gear mounts are?  Also, there is a spot where I need to splice the tubing and to do that I need to put another tube inside the 1/2" tube with rosette welds and then the splice.  What size tubing should I put inside the 1/2" tube and what wall thickness should that be?

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Posted (edited)

I'm starting to get everything squared up.  The 1/2" tubing is .035" wall correct?  Is there any benefit to using tubing with a thicker wall where the gear mounts are?  Also, there is a spot where I need to splice the tubing and to do that I need to put another tube inside the 1/2" tube with rosette welds and then the splice.  What size tubing should I put inside the 1/2" tube and what wall thickness should that be?

Greg,  7/16" x .035 wall (or any wall) should fit snug inside the 1/2" tubing.  I put 9/16" x 035 wall OVER some 1/2' tube, and 5/8" x 035 OVER that to beef up my longerons from strut attach to firewall.  I didn't put the gear tabs back on because I was going to use a different tri-gear mount.      Note:  if snug fit inside of tubing, fishmouth is not required, just 30 degree scarf cut - also, don't think rosettes are required with snug fit, but always good insurance.  Check out AC43-13.  EDMO

Note:  Depending if the original tubing was DOM (Drawn on Mandrel) or extruded, which is cheaper, the wall thickness can vary a couple of thousandths - check ID of 1/2" tube - you might have to ream it or polish the 7/16 to fit.   ED

Edited by EDMO
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