I don't know for sure, but most likely they were steel tubing. That was the most common way to build a whole airplane in the 1930s, before the aluminum-skinned construction became common, and it was used for small planes as well, including the Piper Cub, the Aeronca Champion, and so on, into the '50s and some into the '60s. Today, homebuilts are often made that way in the US. My understanding is that amateur-welded steel tube frames are not allowed for homebuilts in Europe, correct?
Sometime take a look at the sheet metal from which the engines hang in a DeHaviland Comet. It will make you gulp.
Parts for the DC3/ C47 were easy to come by and most of the parts were stock items. Since the military had over 10,000 C-47s there were plenty of spare parts available. The DC3 itself was a very simple aircraft, not like todays flying electronic boxes. There were many variations depending on how the airline ordered the plane. The Pan Am ones had the biggest fuel tanks. You would almost never find any major structural cracks in the wings like you do with later jet aircraft. If you ever check an AD (sirworthness directive) list for a 747 you would probably not fly in one. There is a number of them that list cracks in the main spars of the wing and not to let them get bigger than a certain number of inches.
The frame of the control surface was all metal.
The 747 was a well designed aircraft. It had triple redundant systems on all critical systems. The one engineer that I knew that was heavily involved in the design of that plane told me that they estimated a mechanical failure rate leading to a crash worked out to 1.3 aircraft in 20 years. The plane has a rate better than that, The crash of the one in Japan was due to improper maintenace. The others were from pilot errors or bombs and rockets.
There are still plenty of DC-3 flying, a lot of them are used in the Bahamas, West Indies and south florida. There was one that had been going over our place late in the evening, sounded like it had R1820 Wright engines on it, 9 cylinders with 200 cubic inch each you can tell the difference.
No idea on the homebuilts in Europe except you reminded me a microlight flyer my neighbour knows who I met next door with the top of his control stick asking about repair, it had snapped off when he was coming into land, the lightweight tubing of the control stick had failed at a drilling through it where a control cable ran, no reinforcing of the area. Luckily he was just about to land a no serious damage occurred but it could have been far worse. The microlight looked more like a proper plane as with the regs here and the advanced materials it was fully enclosed.
Regarding your comment about steel tube planes, before you replied it occurred to me earlier that 2 of the reputed greatest British fighter planes of WWII were the Spitfire and Hurricane, the Spitfire being all metal stressed skin construction IIRC and the Hurricane being a steel frame and fabric covered IIRC, 2 differing constructions and makers, same engines IIRC but in the circumstance not much too choose between them, although I have read the Hurricane construction made it less susceptible to damage from bullets and shrapnel.
If I have the chance to see one up close i'll have a look. I went to the Shoreham UK airshore a few weeks ago and had a Lancaster bomber creep up on myself and a mate, it came over the hill behind us and was upwind so we didn't hear it coming until it it was quite close, it passed overhead at maybe 100', amazing noise. Had a group of about 6 spitfires pass over as well many times. Quite a fantastic noise. Looking at the engine cradles they look quite weak but must do the job. It was pointed out to me relatively recently that aero engines differ from car engines in that the engine must have bearings to take all the thrust generated by the prop to drive the plane along.
Seems like a lot of very interesting reminising going on!! hope you dont mind me adding a bit. I was lucky to get my emgineering training on Sunderland Flying boats and then converted to Shackleton 1 and 2. at RAF kinloss. A little while ago!. However its all been so worth while, when hang gliding started in
1976 here in the UK, it was just what I wanted to do. Finished up representing the BHGA at the CAA in London on the air management group. Met some very good people. Now we have some 800 yds away from here a microlite field. there they have the 3 axis under 500kgs fixed wing 2 seaters. they turn finals over the house. Now they have all steel tube welded fuselages with ali main spars inthe wings with wooden ribs and fabric cover on all surfaces. One gronund looped on take off recently and the tubes bent in all sorts of places but none of the welds let go. Definately the CAA dont allow home welding.!! Ed, do you know the book by Ernest Gahn Fate is the Hunter? surely you must? Also you have a plaque of mine from some time ago. Hope all is well with you. Ted Frater Dorset UK.
Here is a picture of a stripped control surface getting ready to be covered. Except for the attach points, almost everything is aluminum. This was the norm for most rag airplanes. The wings were either aluminum or wood. The main spar was usually wood on the early aircraft and the ribs were also wood. On the newer aircraft more aluminium was used in the wings to replace the wood. The main fuselage though, was usually put together with 4340 gas welded steel tubing. Even newer aircraft used welded tubing. The Mooney series of general aviation aircraft used welded tubing covered with an aluminum skin for the fuselage.
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Most of the commercial piston aircraft engines were held on by three pins. You could change out an engine in an hour or two.
The cite for this, I gotta see. If you're speaking of Airbus, I can't argue, but I've got many years of building Boeing widebodies, and your use of the term "glue" is highly misleading. Boeing's wings are bolted and riveted together, and the surfaces between the parts are usually sealed (fay surface sealing) and that sealing does contribute to some degree the strength of the joint, but it's not used in the stress calculations. So, if in a joint there is both rivets and a sealant, can you say it's been "glued?"
It usually is, Carl. The rivets, as they're used in rivet-bonding, are not distributed as they would be in a joint that was riveted for maximum shear strength. There usually are far fewer rivets than would be required to provide much shear strength, and they're mostly located at the edges of the sheets, in a line (more or less), which is not the way to gain maximum strength.
High-strength adhesives in general have very high shear strength but poor peel and cleavage strength. The rivets are there to keep the edges of the aluminum from separating and loading the glue line in either peel or cleavage.
I don't know specifically about Boeing but most commercial aircraft have been rivet-bonded for more than two decades.
That's what I've heard, and it apparently is true throughout continental Europe as well. I can see where the concern is but you may be interested that a lot of homebuilts are made with SAE/AISI 4130 tube in the US, usually in wall thicknesses of 0.065" and less (16 gauge in the UK, I think) and I don't believe there are many failures. Most of it is welded with oxy/acetylene although there is some use of TIG, and very little use of MIG, except in commercially built frames.
Chrome-moly 4130 is very forgiving and lends itself to most welding techniques. Our Experimental Aircraft Association (EAA) holds frame-welding classes and publishes some books on the subject.
Yes, indeed. It was _Fate is the Hunter_ that I was thinking of when I mentioned the DC-2. A great book and an outstanding writer.
I have that plaque on the pegboard above my workbench, Ted. All is well here and I hope the same is true with you.
Very interesting. I guess I shouldn't be surprised that there's a company in the business of making replacement parts and repairing DC-3s. There must be a lot of them still flying.
Right. The VW conversions used for some homebuilts include reduction gears (or a Gilmer belt) but also thrust bearings. I wonder how well the VWs used without the conversion kits last, in such aircraft as the Volksplane.
I don't know, I see that Boeing has a specification for vendors supplying rivet-bonded parts. Are you sure they haven't used rivet-bonding on skins or other structural parts? I think they'd be pretty lonely if they didn't.
I worked on a number of DC-3's in the late 80's. I refitted electronics on two that came out of Chile that had the original command communication equipment from the second world war, incuding the arc-5 units, bc 348 and the BC610 transmitter. I still have the telegraph key somewhere in my collection of stuff. The DC-3 could work out of smaller airports and was a compariaatively inexpensive aircraft to own and operate. A decent cargo DC-3 was running about 150,000 dollars and would haul about 9000 lbs payload. They came with a number of different engines, including the R1820 Wright, R1830 PW and the R2000 PW on the R4-d7 military aircraft. There was one outfit that put a pair of turboprops on a DC-3 and upped the useful load and gross weight of the aircraft.
The VW has some serious issues to overcome for aircraft use.
For one, it has to turn pretty fast (rpm) to make max power - which dictates a short and very inefficient propeller.
That works out pretty well for a high speed ride like a KR-1. But a low speed plane like a Volks Plane (especially a heavy one) needs more prop. Acceleration is anemic and climb can be - well - if-ish? On a hot day it has been called down right scary.
For another, it has very limited cooling area on the heads.
ALL VW aircraft engines should be considered 40 HP engines.
My last parasol had a 2180cc VW. Some people call those 80 HP, but that is only true for 5 minutes or so.
After the heads heat soak you had BETTER throttle back below the
40 hp level.
Or the heads melt, valve seats pop out, valves burn off, and other very bad stuff happens...
The 2180 is an expensive engine to build. But it's about the biggest of the breed. On my last plane, I "over propped" it with a 60 x 30 prop. It turned only 2400 or so static and picked up a few hundred in flight.
Motor heads want MAX HOSSPOWER! And turn up 3500 RPM (or more!) At that speed the (very) short prop (56"?) is less than 50% efficient.
Trick is to maximize THRUST - not horsepower...
Geared engines seem like a great idea, because torque increases and the engine turns up at a higher RPM and makes more HP.
But he heads still limit the ENGINES output to - yep - 40 HP.
For what it's worth...
Richard
Anybody who wants to see the details of my planes... the plans and builders manual are at:
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snipped-for-privacy@earthlink.net.02.11.2006/index.html Scroll down to the Plans download - or the manual download. Heck, splurge and get both!
Photo CD of construction log web site and lots of pictures...
anodising is an oxide treatment. anodising is a process of developing a deep porous oxide which is then impregnated with a dye and sealed in boiling water.
my comment stands. glueing has a strength. if you design the structure to have stresses within that strength then it will work. the key is to know what strength the glueing that you are doing has. if you are glueing to anodising, then what bonding strength does the oxide layer have to the underlying aluminium?
there have been aviation failures which caused a really close look at the dynamics of what occurs. if you want to do this at home be very certain of what you are doing. Stealth Pilot
I didn't download your big file but I see some photos on the Web of the Texas Parasol. I see it's made of 6061 aluminum angle and tube. How do you stick it together, TIG welding?
Phosphoric-acid anodizing creates a very strong bond, while naturally occurring oxide on aluminum is very weak. Yes, it's oxide, but using the term "oxide" rather than "anodizing," without further explanation, implies that you might be bonding to natural oxide. I just want to make sure that was cleared up.
It's very high. You can find the results of lap-shear tests with various adhesives on PAA-treated aluminum. Loctite's Hysol epoxy produces over 6,000 psi:
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Of course. It's not like gluing popsicle sticks. This is for real experts with instrumentation and control.
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