[WerkSpace]

Ok, the title sounds a little bit weird, but it's about welding airframes.
I've seen that most aluminum ultralight frames are bolted or riveted.

If Nascar can weld a car together that can impact a wall at horrendous speeds,
then, why are most aluminum ultralight airframes not welded? Maybe chrome moly instead of aluminum?
Many of the steel airframes are welded. Perhaps, steel would be a better choice than aluminum?

Here's the GOAT ultralight glider and the free plans.
https://www.youtube.com/user/airchairp/videos
http://m-sandlin.info/

Here's the motorized version called the Zigolo.
https://www.youtube.com/watch?v=nfV0lGYJYRo
https://www.youtube.com/watch?v=vPDQ6SUbSM8

The Zigolo reminds me of the Moyes DragonFly that's used at Wallaby Ranch in Florida.
http://www.wallaby.com/aerotow.php
https://www.youtube.com/watch?v=DVfDd7gqFZY

[Antorcha]

The title reminded me of a Pakistani expat thread. " WEDDING a goat"

[Superiorwelding]

Ok, the title sounds a little bit weird, but it's about welding airframes.
I've seen that most aluminum ultralight frames are bolted or riveted.

If Nascar can weld a car together that can impact a wall at horrendous speeds,
they why are most aluminum ultralight airframes not welded? Maybe chrome moly instead of aluminum?
Many of the steel airframes are welded. Perhaps, steel would be a better choice than aluminum?

WerkSpace,
I heard you are working on some experimental aircraft, you will have to get some pictures of your fab work ( if any ).
I get to perform work for a local aircraft club and have asked them why they use rivets instead of welding. My first response was "because that's the way it has always been done". Since then I have held a "school" for one of their monthly meetings. They are slowly moving away from rivets and glue to build their aircraft. I will be welding up a alum fuel tank and they told me the old way was to bond all the pieces together. Anyway with the little knowledge I actually have on experimental aircraft, I say there is no reason you can't weld your frame together. I would have to say that Nascar vehicles are designed to take those impacts, not sure if the aircraft are. Not saying you don't already know this, but I have had several discussions with others explaining how these drivers can survive accidents, whether it be Nascar, NHRA, Rolex 24 etc. I know weight is a major concern you these ultralights, but I see nothing wrong with using 4130 Chrome-Moly, assuming your engine can handle the extra weight. Just a few Saturday morning thoughts.
-Jonathan

[jumpinjackflash]

From Alcoa documents.....Welding 6061-T6-Typically, after welding, the properties near the weld are those of 6061-O, a loss of strength of around 80%. The material can be re-heat-treated to restore -T4 or -T6 temper for the whole piece. After welding, the material can naturally age and restore some of its strength as well. Alcoa Structural Handbook recommends the design strength of the material adjacent to the weld to be taken as 11,000 psi without proper heat treatment after the weld....Typical filler material is 4043 or 5356.
On a side note there are some engineering docs that say it will return to T-4 in the weld area after 96 hours at room temperature. I wouldn't weld on structural parts of T-6. But that's just me.....my airframe is mostly 4130 tube...except for the wing spars.

Here is a most helpful illustration....they did weld a couple of fuselages up , but quickly moved away from welding. A well proven design that has constantly evolved.

http://jameswiebe.wordpress.com/2014/03 ... omment-452

[WerkSpace]

I have purchased the plans for the following aircraft.

The CH701 is a scratch build project from sheet aluminum and rivets.
I purchased a Continental C-85 and McCauley prop, plus a set of tundra tires.
http://www.zenithair.com/stolch701/index1.html

The following video shows the same aircraft with the C-85 engine.
https://www.youtube.com/watch?v=1JOgC1t1SxQ

The second aircraft will most likely be built from a kit, but that is yet to be determined.
I bought the CH750 plans to compare them against the CH701 plans as both aircraft are similar design but 30 years apart.
http://www.zenithair.com/stolch750/index.html

WerkSpace, I heard you are working on some experimental aircraft, you will have to get some pictures of your fab work ( if any ).

[jumpinjackflash]

That's cool...my neighbor is nearing completion of his 701 set up as yours....C-85 with 0-200 crank in a -3 case. He is using the C-85 cam and lifters for more low end torque...they are cast camshafts - the O-200 cam is billet steel...so don't intermix cam followers!

[Otto Nobedder]

Fascinating thread...

Jumpinjackflash's reply makes a great deal of sense, as the average homebuilder does not have the equipment to restore temper to T6, and the mechanical joint is proven in decades of use. Even the professional company selling "ready to fly" aluminum ULs does not really have this option, for what it would do to the cost.

I am a fan of welding fuel tanks, firewalls, etc., where the weld is not a part of the airframe.

Now, I have to go dig out a set of plans I have for an aluminum tube-and-rag UL (true U.S. part 103), and study the materials and joints. Sadly, I can't legally build that one... I didn't buy the plans. I have photocopies a friend gave me for study when I was first interested in the different construction methods.

One thing I noted in my study... A 4130 airframe does not have to be heavier than a 6061 airframe of similar strength. The strength-to-weight ratio of the materials are quite close in a space-frame, and with careful design (beyond my skills), an airframe of either material can be re-designed in the other at a similar weight.

I'm reminded of a quote, that may be straight out of the Lockheed Skunkwerks, "Simplicate, and add lightness."

Steve S

[Otto Nobedder]

Okay,

Looked at the videos. I gotta getta Goat!

155# glider with a 25# 25hp engine? That is well within part 103. I'm in flat country, and tow-launch would have to be by boat if I were to go with a glider...

The Zigolo could be operated as a full-time UL, rather than a self-launching glider.

Fascinating!

Steve S

[WerkSpace]

I've also purchased some plans for hovercraft.
There's some welding involved in these projects.

http://amphibiousmarine.com/hovercraftvideos/
http://www.sevteckits.com/catalog/index ... x&cPath=65

I'm going to start with the Vanguard with a 22hp lawn garden tractor engine.
but I'm resizing the plans by 8/7. (from 7'X14' to 8'X16'.)

The Explorer will come later. It will be 10' X 20'
I've purchased a 3 cylinder, 1 liter, intercooled turbocharged 82hp engine for this project.