Forming 3003 Aluminum

Scott,

3003 is almost dead soft and stays that way. Make a hardwood > Hello. I'm new to the group. I have a question on forming an air

The flange will gather and crinkle unless you draw it down into a mold with a mallet, the way you form ashtrays and candy dishes in hobby work. You will need to leave at least an inch, or inch and a half, to be cut off later, or the material will still gather and crinkle. Then you will have to planish out the mallet marks. This is an art metal technique; it's taught in high school metal shop.

There is another way to do it, used in making homebuilt aircraft parts, using a doorstop-shaped wooden dolly, in which you work out the wrinkles as you work your way around the part. I won't even try to describe it in words.

The easy way is to make it in two parts, and weld it.

BTW, I'm hammered on some 3003, and it's very nice metal to work.

-- Ed Huntress

You got the right ppl ... I do Aircraft sheet metal ...

Forming alum is fun . When you lead hammer the Al' over the edge , you need a special vice that pulls the edge out , But if you pull too hard , it can't shrink , .

As you hammer , it will be obvious , the shrink part will try to buckle ... Just before you see a buckle forming , pull out on the edge ( adjust vice to pull edge out . as you hammer , you'll need to put more tension in it .

All this , for a 3" flange , and all you want is a 1/2" flange !!

BTW , foot operated shrinkers dont work , they eat the alum . But those big 6 inch concave/convex compound curving "stampers" work great .

Some adventures in airplanes .... Gordon B. Hamilton ( TUS AZ ) had C-45's he was stretching , and he wanted me to drill out all the rivets in the fuselage . I put some masking tape on a chisel and slide it down the fuse' snapping off rivet heads at 100 MPH . Someone yelled ! They inspected and found not one gouge in the skin ! 100's of rivet heads laying on the ground ! You simply lift the chisel just before the head pops off .

I used a huge air hammer when i riveted .. buddy borrowed it and put a HUGE dent in fuselage ! He wasn't used to a 3X hammer . I laughed as the engineers tried to figure a long 1/8" AN470AD4-12 thru 4 pieces of 24-ST !!!

They were stretching the old Beechcraft C-45, adding turbo-props, tri-pacer gear .

Love working on airplanes ......

Wana build one , Carbon-Fiber , twin Honda bike engines .... @70HP each engine wt=90 lbs , Engines get a 4 "planet" planetary geabox ( 6 tot gears ) ..

tail dragger looks like P-38 ,

retractable DC-3 landing gear .

Very light wt and very fast ...

Co-pilot seats in the other boom.

Great story Werty...the part is for a Piper Arrow 200. The stock air cleaner lid is shot, costs $1500 from piper (they need to make one), and it will fail just as the original did. I'll weld the flange on my custom part since 3003 is weldable. I'll hammer the depression in the middle. BTW, I'm building an RV-7...wings and tail done.

Scott

werty wrote:

Have you seen the engine replacement for your Piper ? 300 H.P. 2 stroke diesel ( air cooled)

from Zoche .. No spark plugs , no carb heat , no volitile fuel to explode .

It has not , the gasoline 2 stroke problems , of hot spots in cylinder around exhaust ports , sea level power to 25000 ft .

There are NO compromises , Every theory in aircraft engine design was considered !! Notice its only 4 cylinder / 8 cyl dual bank radial .

======== Don't all radial engines have to have an odd number cylinders per bank?

Unka' George (George McDuffee) .............................. Only in Britain could it be thought a defect to be "too clever by half." The probability is that too many people are too stupid by three-quarters.

John Major (b. 1943), British Conservative politician, prime minister. Quoted in: Observer (London, 7 July 1991).

This is just tradition, nothing more. There have been radials with even number of cylinders.

Nick

================= Thanks for the feedback.

I just received this email which may be of interest to the group. It does not appear that 4-stroke radial engines *HAVE* to have an odd number of cylinders, just that they run [sound?] better if they do.

John Deere and Harley have an uneven exhaust beat and seem to work all right.

Received the following information in an email. It may be of interest to the group.

Four-stroke radials almost always have an odd number of cylinders, so that a consistent every-other-piston firing order can be maintained, providing smooth running.

From:

Roger, I'm glad that you found the radial engine article valuable; good luck with your Fokker. To answer your question, let's look at a 7-cylinder engine. As you know, each cylinder has

4 strokes: intake, compression, power and exhaust; and two revolutions of the crankshaft are required to complete the cycle. Thus, it takes two revolutions for all of the cylinders to fire once. The firing order is 1-3-5-7-2-4-6. Notice that the next cylinder to fire is always two away from the cylinder that just fired. This keeps everything in balance. For each piston that's firing at top dead center (TDC), the adjacent cylinders are just short of TDC at the end of their exhaust stroke. This allows the firing cylinders to orbit the engine twice with each crankshaft revolution, producing power pulses that are evenly spaced. If you substitute an even number of cylinders, the transition from the first revolution to the second wouldn't be equally spaced. After all of the odd-numbered cylinders had fired, it would be a three-step-not a two-step-jump to fire the first even-numbered cylinder. At the end of the firing of the even- numbered cylinders, it would be a one-step jump back to the odd-numbered cylinders, and this would create an interruption of the power pulses. I hope this information helps you understand these complex pieces of machinery. From:

Anybody seen a diesel radial?

Unka' George (George McDuffee) .............................. Only in Britain could it be thought a defect to be "too clever by half." The probability is that too many people are too stupid by three-quarters.

John Major (b. 1943), British Conservative politician, prime minister. Quoted in: Observer (London, 7 July 1991).

No. Radials died after WW I, big ones in the beginning of WW II. At that time, they didn't get a Diesel running that was light enough. The Diesels for planes developed in WW II didn't make it into production, because of the invention of the jet. Astonishing how long it took to get a Diesel into planes by Zoche, regarding the developments done during WW II.

Nick