Curtiss Jenny Restoration

Welcome! We hope you enjoy following the restoration process of a 1918 Curtiss JN4D Jenny. Once completed, the aeroplane will be flown and displayed at the Candler Field Museum in Williamson GA (30 miles south of Atlanta). You can contact me below by clicking on "VIEW MY PROFILE"

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Location: Peachtree City, Georgia, United States

Wednesday, June 10, 2009

Left Peach Basket

As of today, the front and rear supports have been welded on the left peach basket !

Here's the rear support after following the bending sequence from the last blog.



Add some heat and pull down with a pair of pliers.



Trim, weld....the finished product! Actually, I blasted the peach basket and gave it a coat of primer to keep it from rusting. The lightening holes need to be drilled yet as do the bolt holes.



Also made the patterns for the tabs that hold the landing gear brace wires.


Here's the first one. It's pretty thick stuff. I used .250 steel. My bandsaw (with the new blade thank goodness) zapped through it without any problems. The rest was shaped on the grinder.


Enjoy
Brian

Monday, June 08, 2009

Left Peach Basket

Of course just when you get on a welding frenzy, your acetelyne tank runs dry! So this morning I had to run to Syd-Lee Welding Supply in Griffin, Ga to re-fill my tank.

Angel Miniet sent me an e-mail with a good observation and I forgot to mention it during the last peach basket construction. He noticed that I butt welded the flanges around the oval and ground the welds smooth. But, he was worried that the ground weld would not be strong enough and recommended that I weld the back side. I had debated doing this, but I worried the heat of welding would distort the oval (which I worked hard to keep straight) and I didn't want to go there. Angel's e-mail was what I needed to convince me to give it a try.

Today I clamped the oval to a piece of angle iron with several c-clamps and burned some of my new acetyline. Angel was right - the weld on the back side of the flange really made things stronger. It wasn't an easy weld because the angle iron acted like a big heat sink and I had to weld into a tight channel. But it went well.

After sandblasting the oval welds, I bent the front support. This gives a good view of the angles.



Here's another picture.



Anyway - Thanks Angel for the advice. If you remember, Angel built a neat model of a Jenny in the Cuban Air Force paint scheme.



He also sent a neat link with an original movie showing some Jennies at a Texas training airfield around World War I. It's worth watching, even if the film is old.

http://www.airspacemag.com/history-of-flight/How_They_Trained.html




A scene from the Army Signal Corps film "Aviation Training in the United States," shot in 1917-1918


Enjoy

Brian

Sunday, June 07, 2009

Peach Basket

All right - I got the rear support finished today. Here are the steps for when you get to do it!

First - bend the 90 degree tab. Make sure this is a sharp bend because it needs to hug the inside flange and you must have the 1 1/2 clearance inside the race for the axle.


Second - over bend the outside flange. If you omitted this step, and the piece stayed flat, the end would hit the peach basket when you made the main bend. Trust me. I learned this the hard way!


Third - I found that if you started a bend line, when you heat the metal, it continues to bend at your seam. If you did not pre-bend this, when you heat the metal and pull the flange into position, it made a curved, kind of "path of least resistance" bend. I found this out the hard way, too. The original peach baskets had a sharp bend and pre-bending slightly helps guide it along. Only bend a little and perhaps a tad more at the top.


Here you can see the angle difference between the top and bottom of the support. This picture was taken after heat was applied along your third bend. Notice that the pre-bent second angle just matches the peach basket angle perfectly. It also sticks up at the end, which leads us to the next step.


Just heat this area and tap it over with a hammer. That's why we drilled a little hole in the flange and cut out the relief.


When I made the pattern, I added extra material along this edge. Previously, I tried guessing the outline and when I bent the support, guess what? They didn't match. The bend pulled up my outline and the bolt holes didn't match. Adding material from the start solves the issue.
Trim away the excess material to match the outline.


Now its time to weld the edges.


Also, don't drill the lightening holes until after the support is welded. If you do, when you heat the bend, the flange doesn't bend evenly. Trust me on this....another thing learned because of a previous mistake.


Now that I'm smarter, I quickly cut out the left side supports and gave them their first bend. But, the rest of the bends will have to wait until tomorow.


Here's the "almost finished Peach Basket" - I have to weld the airfoil supports on the inside yet and drill the final holes.


Speaking of the airfoil, I made the pattern from the drawings and planed the wood to size.
Till next time
Brian

Wednesday, June 03, 2009

Peach Basket brace

OK - I got this peach basket support figured out...finally!

I feel like I've spent as much time building peach baskets than the entire fuselage.

Well, not really. I tried pre-bending the supports before welding them to the peach basket. Every time I adjusted a bend, it changed some other angle and I would have to rebend that angle and the cycle went on and on. I had to guess the angles and bend line locations. Needless to say, that wasn't working.



So, I tried a different method. First, I pre bent the inside flange to 90 degrees. Secondly, I bent the outer edge up and out of the way. You'll see why in a minute. Then, I slightly bent the angle between the oval and side. For the tight bends, I used a 1/4 in piece of flat stock. It worked pretty well.



See, the problem had to do with the bend in the middle. It's a greater angle at the top and virtually no angle at the bottom (near the split). If you didn't bend the end up, it would interefere with the side as you made the center bend. I learned this the hard way. Also, I added some material to cover the bolt hole, too. This would be trimmed to size later.



When you make the center bend, I heated the bend line and pulled the steel down with a vice grips. The steel had a tendancy to arch when you bent it, so keep the flame on the bend line and keep the rest of the steel cold. This will give you a crisper bend.



The bottom flange followed the upward bend and had to be bent over.



After trimming to fit the cutout and the bolt curve, everything was clamped and ready for welding.



After the welding



And cleaned up with the bead blaster.



The rest of the flanges should follow the same method.
Here's a picture of the flanges that didn't bend very well. I admit it - I make mistakes! That's how you learn.


John Gaertner at Blue Swallow Aircraft sent this picture of the lower wing. They are getting close to completion.



Enjoy
Brian