Just found this. Don't think it's been posted here-

Okay, so after seeing this video. And seeing aircraft builders take years to complete their projects I have to ask......

Why not build a Maule????

It only takes five minutes judging from the video!

But to be serious I was surprised to see mig welding on the airframe. always thought that was a no no on 4130?

SE6601KF wrote:Okay, so after seeing this video. And seeing aircraft builders take years to complete their projects I have to ask......

Why not build a Maule????

It only takes five minutes judging from the video!

The guy I bought mine from actually did that. He built an experimental Maule. Six feet shorter wingspan. 300HP engine. Reverse thrust.

SE6601KF wrote:But to be serious I was surprised to see mig welding on the airframe. always thought that was a no no on 4130?

I don't think there's anything wrong with using any of the electrical welding methods on 4130. One reason gas welding is preferred for airframes is because it leaves the structure with no magnetization, which can wreak havoc on compasses and avionics. If it's a repair on a completed aircraft that has installed avionics, running current through the airframe can fry expensive boxes.

The other consideration is concentrated heat during welding, which is always near stress-bearing joints of multiple tubes. Electrical process welding can rapidly heat small areas and do weird stuff, whereas gas welding, you always end up heating the area more slowly and in a larger gradient.

As for whether this has been posted before... viewtopic.php?f=9&t=7470

Deja vu...along with the direction of the conversation.

I wish they were making one for me! Can you guys tell me why they don't use aluminum for frames on tube and fabric planes? I know it would cost more and it's harder to weld but it seems like the weight savings over steel would make it worth it. I always wondered why they don't do that.

Stiffness and yield and buckling and deformation and absorption of energy per unit of deflection and several other things that real engineers with engineering degrees can explain.

However... there are actually a couple of interesting ways to use aluminum for a fuselage structure other than sheet metal semi-monocoque.

A fellow in Texas named Chuck Beeson developed a unique little LSA/ultralight parasol aircraft affectionately called the Texas Chuckbird. There is absolutely nothing remarkable about that aircraft (it's yet another modernization of the classic Heath and Corben parasol designs)... EXCEPT that he figured out that you can save time and money by using extruded angle to build a decent fuselage truss structure. The icing on the cake (actually the key to the whole thing IMHO) is that extruded angles allow you to use strong, inexpensive AN solid rivets instead of blind fasteners.

Now I'm sure the engineers will be quick to point out that a tube is more torsionally stiff than an angle for the same X-section area, and that there may be a little strength to weight difference between common and uncommon aluminum angle alloys. All 100% true. BUT, for a small single seat low speed aircraft, the losses in pure structural efficiency might add up to five pounds or probably less, which IMHO is more than offset by several big advantages.

The disadvantages start to get proportionately larger as the size/weight/speed of the aircraft goes up, so by the time you build a Maule size airplane capable of the same rough service, this riveted angle method may well not be as advantageous as welded steel tube.

Another thing I wonder about is the use of honeycomb laminate panels in kits that use wood floors or fuselages. I looked into replacing a top on a houseboat with Honeycomb panels. They are a third the weight and 10 times stronger that wood. Seems like there is a lot of room for improvement using newer materials than before?