More I-struts

3/22/2008

I-Struts

I finished up heat bending the lower box sections, this time heating the correct side...heat bending the underside of the box section is visually tricky, so I used a mirror [see inset pic]

I have left the spar bolt locating holes off of these, these will be drilled when the completed I-strut has finished moving around during welding.

The streamline tubes arrived, so I have started to fabricate them. The ends of the struts are at a compound angle, so tricky to cut accurately. I really didn't want a bad hair day by cutting them wrong [cost], so I first made a mock up out of a stud 2X4. This was then used for reference. For curiosity's sake, I checked the mock up on the other wing, and found I was only off by 1/32, not bad. The streamline tubing is now clamped in place, and I am just about ready to start tack welding them.

Interesting note: the streamline tubing on the 91 plans is different than on the early 75 plans. I compared the new tubing to the old I-struts I have, and there is a big difference in size and weight, the new stuff being slightly smaller and with a thinner wall.

Aileron stops

I made the stops at the stick end out of solid bar. A hole was drilled all the way through, then tapped in about 1 inch for a AN3 bolt. As yet , they need tacking on the fuselage.

Engine Mount

I have decided on using an IO-360 angle valve, so I can now order my engine mount, this is coming from Steen. It occurred to me that the chances of a jig-built mount blindly fitting a 75 'bolt fuselage are about as equal to me looking good in a tight Spiderman outfit. So I made an MDF template with steel bushing plates for the locating holes. I will be shipping this to them.

To come: next, I will be tacking the bracing tubes on the I-struts, then I intend to make a 2x4 lumbar cradle/jig to house the struts to minimize movement, at which time they will go to my high class tig welding buddy for finish welding. Then I can finally dismantle the wings, turn the plane upside, and focus on fitting the cabane compression tube and glass cabane fairing. Then I can store away the wings and start playing with the fuselage and landing gear.