mjk51
Member
This gets a little confusing but stay with me...
Just got the upper wing of my Firebolt mounted onto the cabanes for the rigging process. They lined up well and are now bolted in. Things are going smooth....and then.. I set the lower wings into position. Ran the front spar bolt thru the fuselage fitting and leveled the lower wings chordwise. The fuselage is in a 2 degree nose down attitude...(And so am I.) The rear fitting bolt hole is lined up with the bottom face of the rear spar. Nearly 3/4" from its proper position. I checked and re-checked the spar fitting, fuselage fittings and cannot find an error. Some of you guys that have been thru this process can check my logic on this, and you other Firebolt builders can check your plans to see if they match mine...
#1 The fuselage wing attach fittings are welded on with the 2 degree incidence angle applied. That is the front fitting is mounted higher than the rear fitting.
#2 The spar attach plates on the wings are drilled 1 9/32" below centerline on the front spar and 11/16" below centerline on the rear spar. This hole position trigs out to a 1.47 degree angle from the spars centerline.
#3 With the fuselage fitting at 2 degrees and the wing bolt position at 1.47 degrees I am getting 3.47 degrees total incidence angle. When the rear spar hole aligns with the rear fuselage fitting. It seems to me that drilling the front and rear spars on centerline would put the wing at 2 degrees incidence when bolted to the fuselage attach fittings...As I see it I am compounding my incidence between the spar holes and the fuselage holes..Right..??? All feedback is appreciated.
You Skybolt builders... are your fuselage fittings welded on level, or with the incidence angle applied?
Just got the upper wing of my Firebolt mounted onto the cabanes for the rigging process. They lined up well and are now bolted in. Things are going smooth....and then.. I set the lower wings into position. Ran the front spar bolt thru the fuselage fitting and leveled the lower wings chordwise. The fuselage is in a 2 degree nose down attitude...(And so am I.) The rear fitting bolt hole is lined up with the bottom face of the rear spar. Nearly 3/4" from its proper position. I checked and re-checked the spar fitting, fuselage fittings and cannot find an error. Some of you guys that have been thru this process can check my logic on this, and you other Firebolt builders can check your plans to see if they match mine...
#1 The fuselage wing attach fittings are welded on with the 2 degree incidence angle applied. That is the front fitting is mounted higher than the rear fitting.
#2 The spar attach plates on the wings are drilled 1 9/32" below centerline on the front spar and 11/16" below centerline on the rear spar. This hole position trigs out to a 1.47 degree angle from the spars centerline.
#3 With the fuselage fitting at 2 degrees and the wing bolt position at 1.47 degrees I am getting 3.47 degrees total incidence angle. When the rear spar hole aligns with the rear fuselage fitting. It seems to me that drilling the front and rear spars on centerline would put the wing at 2 degrees incidence when bolted to the fuselage attach fittings...As I see it I am compounding my incidence between the spar holes and the fuselage holes..Right..??? All feedback is appreciated.
You Skybolt builders... are your fuselage fittings welded on level, or with the incidence angle applied?
