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

Thursday, April 26, 2007

fuselage beginning

First thing today, I finished bolting the spider plate to the plywood. I made sure the entire thing was true and vertical. The plate height was calculated from the upper longeron plan. By a little higher math, I calculated that the height should be 8 1/16 in.

The 2 X 4 pieces held the plywood rigid.

Now, the longerons were set in place. I drilled the 5/16 in. holes where the ash met the spider plate and put some temporary AN-5 bolts in place. The cross braces held everything in place.

Also derrived from the Curtiss drawings - at 18 21/32nds from the firewall, the longeron should curve above the table 1 15/16 in. The triangular block was cut to that height.

Then, pull the clamps tight. It worked pretty well! I was pleased.

Next step is to taper the end of the longeron to 1 1/2in and cut for the splice. Till then...


Tuesday, April 24, 2007

Longeron jigs

After doing some thinking the other day, I decided to make a better longeron jig. I bought some MDF board at Lowes. This was much nicer to shape than plywood. And it came in 3/4 in thickness, so two pieces equal the width of the longeron.

Below is my friend and fellow Bucker pilot Dave Daugherty. He's clamping the upper longeron in the new jig.

Here's the lower longeron jig being cut.

Finished product. A bit of advice - Just when you think you allowed enough extra curve for springback, add even more! I was amazed at the woods memory. This will make your life easier.

This jig has a deeper bend. We'll see how it goes when we fire up the steamer next week.


Monday, April 23, 2007

Early fuselage layout

Thanks to my friend and future Jenny builder Kevin Connor, a "new" original Elgin Tachometer was located for the Jenny instrument panel. Kevin was kind enough to part with his treasure and the box arrived from Oklahoma the other day. Thanks, Kevin.

Grinding time today - Now that the upper longerons were steam bent, I needed to modify the OX-5 spider plate for the larger Hisso radiator. If you remember, I was fortunate to get a finished spider plate from Doc Hood. The OX-5 radiator was flat bottomed and rested on a lip at the bottom of the spider plate. The Hisso radiator is curved at the bottom (to provide more surface area and more cooling) and rests on a curved lip on the spider plate.

So, I had to grind off the straight lip in anticipation of welding on the new curved piece in its place.

Here's the spider plate without the lip.

The upper longerons were put back into the jig, measured and cut to fit into the spider plate.

Finished cut below.

Next step - bolt the spider plate onto the end of the table, attach the longerons and make the splice behind the cockpit. Stay tuned!


Tuesday, April 17, 2007

steam bending

The last steam bending attempt went OK, but I still have more longerons to bend and I wasn't all that confident with the process yet. I knew there were some tricks of the trade floating around out there. I just needed to find them.

After a chance phone call with my old TWA chief pilot, he mentioned that his son and daughter-in-law make canoes for a living and have tons of experience with a steam bender. I pulled up their website and called them right away.

I could not have stumbled into anyone better to help me learn this process! In 30 minutes, Dylan Schoelzel walked me through the process, answered my questions and gave me lots of useful tips. I am forever grateful.

For those of you following in my footsteps, here are a few of those tips:

Pre-soak your wood - I complained to Dylan that my longerons did not willingly go around my bend, even after steaming. Dylan told me that my kiln dried ash was really dry and that soaking them in water for 24 hours would help soften them up. So, I got some 4 in. PVC pipe and filled it with water. The kids slide came in handy...again...even though I had to beg forgiveness...again.

This really helped the bending process. When the wood came out of the steamer, it went around the jig with little resistance.

Make the appropriate jig - Since my ash is not square (1.5 in. X 1.25 in.) the wood will have a tendency to twist. Dylan warned me about this and I had that happen with the last bending attempt. So, I had to make a new jig with a ridge (see above) to not only clamp the wood on the curve, but clamp it to the ridge to keep it from twisting.

Allow for springback - Add about an inch on either side of the arc you want to bend. The wood will spring back a little after it is removed from the jig. Also, let a foot of wood hang over the edge. It's nearly impossible to start the bend right at the end of the longeron. Plan on your bend occurring a foot downstream. Same for the other side.

This is the upper longeron in the jig. I have to build the lower longeron jig next.

Here are the clamps in place.

Thanks again to Dylan and Emilie Schoelzel at the Thompson Canoe Works. Their tips were invaluable.

More soon


Friday, April 13, 2007

Steam Bending

"Now, what does this contraption do again?" my wife asked me.
"It's supposed to make a lot of steam," I replied.
"The kids want their slide back."

Guess I should have asked them first.

Anyway, the above picture was my first attempt at steam bending the 1 1/2in. X 1 1/4 in. ash longerons. Using my new steam kettle, I turned the gas grill on high and waited for results. Sure enough, a little steam came out of the open end. Great! This steam bending would be a piece of cake, I thought. Nothing to it. Just let it steam away for an hour for each inch of wood thickness and slip it into the form.

Well, after an hour and a half, I pulled the ash strips out. They were barely even wet! I could even touch them with my bare hand. Hmmm. Something was not right.

I called my friend John Gaertner in Virginia. Always willing to help, he listened to my tale and made a few suggestions from his experience steam bending skids for a Wright Flyer reproduction. "You need more heat," he told me. "A lot of heat! You want the steam to exit the drain holes like it was coming out of a locomotive."

Taking his advice, I called Nate Hammond. He quickly borrowed his Dad's Turkey Deep Fryer. The burner was capable 55,000 BTU's. "That ought to do it," he reasoned.

So, the gas grill was moved back into it's usual spot on the porch and the Turkey burner put in it's place. Boy, did it ever make a lot of steam! I stuck the ash back into the "Ivey Steamer" and went back into the shop to work on other things. I had an hour to wait.

After about an hour, I decided to check on the progress. Steam had stopped coming out of the box, even though the pot was boiling like mad. Something was wrong. After scratching my head, I finally figured it out.

There was a low spot in the hose and it filled up with water! The steam could not get through.

You can see it in the photo above.

After adjusting the hose, the steam started to flow. I steamed another hour and pulled out the longerons. Quickly, I put them into their forms - one upper and one lower.

We'll see how they hold their shape after drying for 24 hours. Some things I learned:

-make sure you have a full propane tank.
-check the water level often. (yes, I ran it dry once!)
-use the heaviest blocks for your formers. Even though the ash was steamed, I still had to put quite a bit of pressure on the clamps to follow the shape. I probably should have used heavier blocks, like Paul Dougherty mentioned. Mine worked, but bigger would have been better in this case.

More soon


Monday, April 09, 2007

Fuselage Steam Box

After a bit of frustration - I'm ready to steam bend the ash longerons!

Some background information - I tried building a steam bender out of aluminum down spouting from a local home improvement store. It seemed like a good idea. Cheap. Simple. Effective. Right?

Well, I fought with it, trying to seal the ends and getting the whole thing to work properly. When the frustration reached it's peak, I put down the tools and went to work. Perhaps a nice long flight would give me time to think about it.

By chance, I was scheduled to fly with Walter Ivey, who is not only a consummate aviator, but a darn good woodworker as well. Walt had built a steam box while making a water ski for his son. With a little modification, he reasoned that the box would be exactly what I needed. Needless to say, I took him up on his generous offer.

I named it "The Ivey Steamer"

Now, how to make all that steam. I looked into many options - electric kettles, bathroom steamer, wall paper remover.....I kept looking for several things: large water capacity, large volume of steam, and small price.

What seemed to fit the bill was a big roasting pot I found at Walmart. I drilled a hole in the lid for an AN12 sized fitting. The hose will run from this fitting to another AN12 fitting in the Ivey Steamer. Inside the box, there are a few wooden pieces glued across the box to keep the ash elevated. Sometimes, you see dowels in a steam box to keep the wood off the bottom, but Walter's wooden ridges work the same way.

See below:

Don't forget to drill drain holes in the bottom!

You only have a few minutes to form the hot, wet ash, I plotted the points for the upper and lower longerons on the jig table. The forming blocks were once again attached to the table with screws.

Tomorrow, I hope to fire up the steamer. Since I had a little extra time before the kids came home from school, I assembled the rudder bar hardware. Looks a lot better now!