How It's Made: Maule

[ZPilot]

A fun watch.

[Zzz]

Nice find!!

[58Skylane]

Nice find! Thanks for posting it.

[Darinh]

That is a good find. I didn't know Maule used pull rivets for the wing skins. I also found it interesting that they MIG weld the fuse...seems like most guys frown on MIG welding 4130. I have always been told that TIG or gas welding is best for chromo.

[ZPilot]

Thanks for fixing the post Zane. I tried the "[/youtube]" and video uploading and it did not take.

[Zzz]

Thanks for fixing the post Zane. I tried the "[/youtube]" and video uploading and it did not take.

Not me, probably MountainMatt.

[maules.com]

Darinh quote 'I didn't know Maule used pull rivets for the wing skins.'end quote

There are very few in each wing. The large majority are shot and bucked.
Jeremy

[Scouter]

Funny, I always thought they were built by Polish Farmers

Seriously, I looked at an 04 M7 for sale in PA a couple weeks ago, it was a very nicely finished plane. Had a couple boogers in the fabric, but was a vast improvment in fit and finish to the older quality out of the factory. A very nice bird, and priced right.

J

[Redbaron180]

so why did the guy put the strut bolt in backwards?

[maules.com]

so why did the guy put the strut bolt in backwards?

The final bolt goes in from the front which replaces the assembly aid.

[lownslow79]

Wow, thats a neat video! Always loved Maules. I grew up about 4 miles from Napoleon, Michigan, which is the site of the original Maule factory/chicken coupe. Napoleon, still maintains a beautiful wide and lush green turf landing field. I am super excited for this upcoming fall. I am going to be enrolled in Northwestern Michigan College aviation flight program. They own and operate a Super cub for tailwheel and float add on's. Since I already have a PPL and 500+ hours, i expect to dive into the Instrument right away, but am hoping to squeeze in my tailwheel endorsement.

[eh009us]

It thought it interesting that they fluted the ribs after fitting them to the spars. On my Bearhawk this is done on the bench with the nose and middle ribs, then you fit them to the spars. My frame is gas welded though . Very similar construction processes though. Just a different way of doing it. Cool video.

[Zzz]

I also found it interesting that they MIG weld the fuse...seems like most guys frown on MIG welding 4130. I have always been told that TIG or gas welding is best for chromo.

I'd be curious to get to the bottom of this. It was my understanding that MIG was avoided in aviation because it really wreaks havoc on the magnetization of a ferrous alloy structure, making compass caging difficult. MIG is controllable and clean and penetrates fine to be plenty strong enough for airframe welding, so in my opinion the case for gas welding being stronger seems like more of an old builder's tale. It's probably more tradition than anything given than welded steel fuselages far predate inert gas shielded welding. I think other factors like piece fit, area/joint prep, heat control (slow cooldown), and the welder's skill play a much larger role.

Perhaps during repair work it is preferable to use a non-electric weld to avoid smoking electrical system components or avionics that are grounded to the fuse.

I found this thread that talks some specifics about why the MIG/chromo thing may have started, but consensus is that it's ok.

Of course TIG is the bee's knees, and how most modern chromoly and aluminum bicycle frames are built by the master welders in Taiwan. I'm serious, the most beautiful welds in history come from those shops that large bike mfrs outsource to in Asia. Bike frames are abused something fierce (in the BMX world.)

[eh009us]

Getting to the bottom Zane is more like a bottomless pit when you do searches on the merits of each as you've already seen. I'd have no issues with TIg, I just happen to have the gas equipment. I do know that when a lot of guys are "tacking" frames and mounts together, they will mig or arc weld just the tacks, then go back and gas or tig weld for the finish weld. (mig and arc can be done 1 handed when you're just trying to get the steel tacked-in). One of the issues with the electric type of welding, at least back in the day, is cracking near the weld since the heat is so high that in some cases the weld would crystalize. Again, another Pandora's box. Anyway, like I said, the debate is endless and pointless in my case since I only have oxy/acetylene anyway.....

[qmdv]

I'm serious, the most beautiful welds in history come from those shops that large bike mfrs outsource to in Asia. Bike frames are abused something fierce (in the BMX world.)

A guy that I went to high school with's dad was a welder at Jet Propultion Labs in Pasadena, CA. He helped fabricate some of the hardware that went to the moon. I have been welding all my life just about and I have seen his welds. Tough to beet.

Tim

[hardtailjohn]

Stinsons were arc welded... and I've never heard of a problem with them failing. Some of them aren't the prettiest, but you can't argue with success!
John

[eh009us]

One way to get around the arc welding from what I understand is to heat the weld by torch or "bake" the frame by oven to stress relieve the welds. Not sure if this was Stinson's method or just left it as is.

[Zzz]

Bump for How It's Made Friday.

[EZFlap]

When I went to A&P school (1981), it was made clear that after any type of arc welding, you were supposed to bake the fuselage in an oven to stress relieve all of those temperature gradients and heat affected zones. Gas welds did not require this but it was suggested.... "for best results".

More recently I have heard that these regulations (or customs) have been softened down somewhat over the years. Similar to the softening of requirement for the number of threads showing outside a nut (was 3 when I was educated, now I understand it's 1).

So I'd also love to hear from those in the know, as to what is best, second best, and not good enough... and where on that spctrum an average steel tube fuselage falls.

[Zzz]

When I went to A&P school (1981), it was made clear that after any type of arc welding, you were supposed to bake the fuselage in an oven to stress relieve all of those temperature gradients and heat affected zones. Gas welds did not require this but it was suggested.... "for best results".

I believe this is called "normalization."