Curtiss Jenny Restoration

Welcome! We hope you enjoy following the restoration process of a 1918 Curtiss JN4D Jenny. Once completed, the aeroplane will be 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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Name: Brian Karli
Location: Peachtree City, Georgia, United States

Friday, July 03, 2009

Landing Gear brace wire fittings

Back in the shop all day today! Continuing where I left off before vacation, I cut out the last three landing gear wire fittings. The rough shape was cut with the bandsaw.


And ground on the bench grinder. It's pretty thick steel (.250) so grinding took a lot of time.

Then the approximate angle was bent using the torch and a hammer.


And the 5/16 in. holes were drilled too.



Here are the fittings out of the bead blaster and ready for primer.



The front fitting goes here.



And the rear fitting goes here.


It doesn't seem like a full day's work, but cutting and grinding the thick steel took lots of time. You can't rush a Jenny...on the ground or in the air!
Have a good 4th of July holiday.
More later...
Brian

Wednesday, July 01, 2009

Back from Vacation

The family and I just returned from a wonderful vacation to our native Central Pennsylvania. We had a great time and the weather was perfect. Besides watching the kids get spoiled by the grandparents, I had an opportunity to visit the Golden Age Air Museum in Bethel, PA. Their Jenny is close to making its first flight and I took lots of pictures.



While I was there, Paul Dougherty and his father attached the horse hair filled cockpit coaming....



....and Mike Damiami worked on getting the OX-5 ready to run. Mike works Technical Support for Lycoming Aircraft Engines during the week and on the weekends, he lends his expertise to the museum. He is a valuable source of information. I know. I've called his number before when the Lycoming in my Bucker was giving me fits.



Before I left, I picked up some original sheet metal from a Jenny rear cockpit. I don't know how I got it to fit it into the van filled with luggage, DVD players, coloring books, baseball gloves, four kids, one wife, a dog and a cooler full of beverages, but I did and the cockpit sheet metal made it to Georgia safely.



Of course I had to put it on the airplane...just to see if it fit!



Gotta fly tomorow, but I expect work to resume on the Jenny Friday. Till then

Enjoy

Brian

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

Sunday, May 31, 2009

Peach Basket - some good & some bad

Good news - the mail man came yesterday with a big box.





"Whats in the box, dad?"





"Oh, Jenny wing struts."

"They are dirty," replied Brighton, with the logic of a two and a half year old.




"Let me help."




Sure enough, the box was full of original Jenny wing struts that Gary Kahl of Clear Lake, Iowa pulled out of an attic. Three of the struts are useable. Unfortunately, the rest were either cracked, warped or broken. But they are good for patterns !




Check out these cool strut markings.






OK, now back to the peach baskets.

As you recall, I made the front peach basket support plate out of 1/16 in. steel. That was the easy part. I put a 90 degree bend on one end and figured, with some heat, the other two funky bends will melt right around there. Wrong! The material was too thick to "easily" bend. You couldn't tap it around like I thought. I even welded the plate to the peach basket to help hold the plate while I applied the heat and bent the steel. It did not go well. So in frustration, I left the shop without putting away the tools. It was one of those days....



I thought about it the next day. I knew I could do better. We learn from our mistakes, right? So, out came the grinder and off came the support.

I decided to make some steel patterns out of some .020 stock which could be bent practically by hand. This way, I could see where the bend lines had to be before transfering them to the thick steel.




This raised another issue. The axle is a 1 1/2 in. tube and it rides up and down in the peach basket. I measured the opening - 1 5/8 in. Perfect, right? That's a 1 1/2 in. axle and two 1/16 in plates.

Not exactly.



With the two side plates installed (with the 1/16 in. material) the axle was a really tight fit. Looks like I will have to grind out the opening a little larger. The bends in the side plates are not exact right angles (bend allowance) so I really need a 1 3/4 in opening.

Oh, the things you learn when rebuilding an aeroplane.

Later

Brian

Wednesday, May 27, 2009

Peach Basket

There are two side supports on the Peach Baskets. These were cut out from some 1/16 in. sheet steel on the bandsaw.


Here you can see the paper pattern. I only had a drawing for the front support, so I had to make my own pattern for the back one. It wasn't too bad.

But after the third support was cut, my bandsaw blade broke in half ! Ahhh. I shouldn't complain. The bandsaw had been faithfully cutting for several years. I ordered a new blade from MSC and it should be here today.
But, not to stop working - I drilled the lightening holes in the supports.


Here's the flat pattern in place. The flange has been bent 90 degrees to go inside the axle race and the rest of the support gets twisted to match the peach basket. I'll do this with a torch later.


Also, the front gear airfoil support was made on the form.


It will be welded here.


More later
Brian

Monday, May 25, 2009

Peach Baskets

Lots of time was spent today with the plumb bob, yardstick and buble level because I wanted to drill the holes in the gear legs. Perhaps I spent too much time measuring, but I wanted to make sure things were straight before I drilled the holes. Several times, I had to sand a little off each gear leg to make them fit.

First, I pre-drilled the gear leg holes in the peach basket. I made these holes undersized just in case I had to make some last minute adjustments. Then I put the gear legs in place and drilled through the wood. I'll drill them to the correct size when I'm satisfied everything is square.

The two tie rod holes were drilled to 5/16 in.



There are two threaded tie rods thah hold the peach baskets together. These will be hidden by the spruce airfoil to be built later.



The tie rods were temporarily secured with AN nuts.



Here they are. I was amazed how strong everything had become once the tie rods were secured.



More later
Brian

Friday, May 22, 2009

Peach basket

Spent a lot of time grinding and sanding today. Here's how the peach baskets look after bead blasting and painting.




There is a wooden airfoil shape between the gear legs. It hides the axle. The airfoil is held in place by a front and rear "socket" made from 1/16 in. sheet steel. I made the wooden pattern for the front socket today.




And the pattern for the rear socket. These sockets are welded to the inside of the peach baskets.




Welding the peach baskets tightened things up a bit, plus the addition of the front-to-rear support piece meant I had to re-fit the gear legs. Some time on the bandsaw and sander took care of that.



This is pretty neat - here's an original wing strut salvaged by Gary Kahl of Clear Lake Iowa. It was sent to me today and the strut turned out to be in great shape. Check out that Curtiss logo! Hasn't been touched since 1918, probably.


Recently, I received an e-mail from John Atkinson. John is a colledge student in Michigan and owns a Piper Pacer. He really likes Jennies and hopes to build one someday. He was kind enough to send a picture of the Jenny at the Air Force Museum in Dayton, OH. It's a great picture and I thought it needed to be shared with everyone.


Thanks, John
Enjoy
Brian