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PostPosted: Mon Aug 29, 2005 7:37 am
by russell
About the pioneer engine series. What type/alloy/temper aluminum is used for the plates that attach the lower wing strut to the end of the axle? 6061 T6?

PostPosted: Mon Aug 29, 2005 10:55 pm
by Chappy

It's not 6061-T6. Ultraflight used a lot of 7075-T6 plate for fittings, although some may have been 2024-T3. If you can't find 7075, it might be best to make the plates a little thicker if you use 2024.

I wish I could be more specific, but Ultraflight did not publish this info.

These fittings need replacement on my series 1, as the bolt holes where the lift struts attach are elongating. I plan to make them thicker anyway so this doesn't happen again.


PostPosted: Tue Aug 30, 2005 7:17 am
by russell
The fittings that I am questioning have what I call a laminate corrosion. The corrosion has started on the bottom edge and is similar to sort of separating into layers. Kinda like lifting the bread up on a sandwich, for the lack of a better discribtion. 6061-T6 6 is gonna be hard enough to find so I can forget about finding the others you mentioned around here. How does cutting off the bottom corroding part about a half inch from the edge and reusing these and adding newly fabricated fittings made of 6060-T6 to these (doubling up)? Man I hate this messing around with these types of original designs, I'm far from being an engineer.

PostPosted: Tue Aug 30, 2005 7:48 am
by xgary ... 075-T6.htm

Design Criteria:
Cost: $1.00 - $9.00 per kg
Density: 2700 - 2800 kg/m
Young's Modulus: 70 GPa
Tensile Strength: 517 - 572 MPa
Corrosion Resistance: Not very corrosion resistant
Machinability: Forming, Welding, Heat Treatment, Forging, Hot Working,
Cold Working, Annealing, Aging, Tempering, Hardening

Why we use7075 instead of 6061 ?

Aluminum alloy 7075 is one of the highest strength aluminum alloys available. It's strength to weight ratio is excellent, and it is ideally used for highly stressed parts such as aircraft components. Thus it is known as a true "Aircraft Grade" aluminum.

7075 vs 6061 Comparison Chart: Alloy Tensile Strength Yield Strength Brinell Hardness
6061-T6 45,000 PSI 40,000 PSI 95
7075-T6 83,000 PSI 73,000 PSI 150 ... 7075t6.php

PostPosted: Tue Aug 30, 2005 9:57 am
by russell
Thanks Shorty,
That's a lot of info. Tells me every thing I should know about this type aluminum that Chappy recommended. Thanks for the web sites also, these will surely go in my files. Well, I guess the search is on. Hey, Don Gardiner, don't be surprisrd if you get a phone call!

I sure am glad I found this site,

PostPosted: Tue Aug 30, 2005 1:36 pm
by Billm
The one (and probably only) advantage to the 60series aluminums (ie 6061, etc) is that they are corrosion resistant. That is why we use them to build aircraft TOOLS (ie, jigs and fixtures) but not airplanes here at Boeing as well as Lockheed, GD and most of the others. That way we can get away with not painting them so much.

PostPosted: Tue Aug 30, 2005 1:45 pm
by lazairiii

I have a set sitting on my shelf that may still have the ink stamped on it. I'll try and remember to look tonight for you.


PostPosted: Tue Aug 30, 2005 3:49 pm
by russell
George, you wouldn't tease an old man now would ya? If you have these fittings and are willing to part with them I would be forever in your debt, well maybe not forever, but a long time anyway!

PostPosted: Tue Aug 30, 2005 4:25 pm
by lazairiii
Hahaha! Tease you? You bet!! But the truth is I may still have some (new) that are from my series II kit that I didn't use when I converted to the wide gear mod during initial construction. Again, I'll be looking into it for you tonight, so cross your fingers!

PostPosted: Tue Aug 30, 2005 4:33 pm
by lazairiii

What's up with your existing ones...corrosion, broken, cracked, bent or just plain seen better days???