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, December 29, 2010

Center Section, Radiator and Visitors

The other evening, we drilled holes in the center section for the upper cabane strut fittings.

Here you can see the fitting in place to double check that the holes were located in the correct spot...on the top side too...because...

...that way the drilling jig can be used.

We drilled the 5/16 in holes with a long drill bit.

All the wing hold down plates and cabane fittings were designed to use bolts with tapered heads. The taper was located on the underside of the bolt head. This allowed some adjustment during rigging. I don't have any original bolts and you can't get them at a hardware supply house. Of course you could make them, but there is another acceptable way.

You can buy spherical washers and put them under the bolt heads. That's what we did.

This works perfectly. The spherical washers come a little too think to use right out of the box, so we had to grind down the top end until the thickness we wanted was reached. One bolt goes where you can see it and the other bolt goes inside the fitting itself.

For any of you future Jenny restorers out there, here's the information about the washers:

Purchased from McMaster Carr - 18-8 Stainless Steel Self Aligning Washers, Male Half, 5/16 in. Screw Size Part Number 91944A106

Thanks to Paul Dougherty at the Golden Age Air Museum for that information! Paul is finishing up a LoRhone powered Fokker Triplane whenever he is not bothered by phone calls from me asking Jenny questions! Check it out:

Now that the cabane fittings were temporarily bolted to the center section, the cabane struts needed to be hollowed out for the bolt head (and spherical washer) to fit.

Here you can see all four cabane struts in their sockets.

Another trial fit!

The Jenny has a 16 inch stagger between the top wing and the lower wing. We measured and found out the center section was two inches too far rearward. This was frustrating because the cabane struts were built exactly to the drawing specifications. So, the struts will need different angles cut on the top and bottom. I decided to do this another day.

I really wanted to get the other side of the radiator finished instead. So a brass strip was cut and held in place.

Solder (and flux) were added using a Butane torch..

And the excess ground smooth.

That was it for one night.

On Wednesday, I got a visitor to the hangar. Jim Lachendro was on an Atlanta layover with his airline and came to see the Jenny. Jim lives in Scotland now but grew up in the States. As a kid, he was an old aeroplane nut like me and I was amazed by the same people, places and old aeroplanes we knew.

John Gaertner drove down from Virginia that day too. He wanted to film a segment for his new DVD showing the lost art of cable splicing.

When I wanted to learn how to splice cables, I was fortunate enough that Paul Dougherty showed me how to do it and he taught me some really great tricks Andrew King developed to make the splicing easier. Of course I got home and forgot half of what he said so I had to relearn it the hard way (making mistakes, reading the Brimm and Boges manual and making frantic phone calls to Paul who patiently tried to talk me through a splice from miles away.).

So John and I agreed that it sure would have been easier if a video would be available to teach people like me who wanted to know how to make the 5 Tuck Navy Splices.

John also filmed the progress we had made since his last visit six months ago. His DVD's on woodworking have been selling like hotcakes.

John also brought the fuel gauge. Doc Hood was kind enough to send me some of his hand made drawings (which would rival Glen Curtiss' engineering department itself) and we used them to make all the internal parts. But we used the original Curtiss fuel tank drawing to get the length of the float rods and the rods turned out to be an inch too long. Just like the fuel tank cradle, the drawings were probably for the JN4D2 version which was never produced but whose drawings survive. So the fuel gauge went back to John's shop for modification.

We also had a visit from Jim Renwick who lives down the road in Senoia, GA. Jim brought a long prop for us to see in the back of his pickup truck. The prop was from a Liberty powered flying boat. I forgot the type. The prop was one of two props bolted together to make a four bladed propeller back then. Pretty neat find.

Lastly, I got two responses from my request to find information about the Hisso fuel pump. Philippe Villard from France sent me two great articles on the Hisso engine. The were written in French, but that was OK. My neighbor translated them for me. It answered a few of my questions. Plus, Paul Dougherty sent me an e-maile noting that the pump in the picture looked similar to the water pump on the OX-5. He wondered if it could be adapted to the Hisso. Gotta check that out.

I appreciated the responses.

More later. Enjoy!


Thursday, December 23, 2010


When I had a company build the radiator, they did a marvelous job, but the flange on the side was not correct. I asked for an .050 gap and I got a .250 gap. The flange hangs over the side of the spider plate and keeps the radiator from moving side to side. So, I ground off the flange and decided to build another one.

Here you can see how the radiator fits against the plate. I cut off most of the old flange.

I never did any brass soldering before, so I practiced on a piece of scrap brass using a Bernzomatic torch, some flux and 50/50 solder. It was easier to do than I expected.

So, A 3/4 in. strip was cut from the copper purchased from McMaster Carr. Their catalog listed all kinds of brass, but after some discussion with John Gaertner, I decided to get Formable Brass Alloy 260.

Nervously, we fired up the torch and soldered the first six inches of the flange. No problem! With a generous amount of flux, the solder flowed nicely. I wanted to make the joint look finished, so we went over the joint with a dremel tool and a small sanding wheel.

Filled with new confidence, the rest of the flange was soldered and dressed.

The new flange now fits the spider plate perfectly. The .050 lip will eventually fit the .040 sheet metal side cowling.

Last week when we trial fit the engine and radiator, we discovered that the water well touched the Hisso cylinder banks. So, the corners of the well were removed. New copper will be added. It was getting late and we decided to keep this job for the next time.

We had the radiator made using the OX-5 radiator drawing. I was surprised to see the water well touch the cylinders. This bothered me. I didn't want to cut up a perfectly good radiator but there was no other choice. However, looking at some pictures I took of the Waldo Pepper Hisso powered Standard J1 in Kermit Weeks' collection, I noticed that Otto Timm did the same thing to make his radiator fit the Hisso - cut off the ends.

I suddenly felt better.

If you notice, they cut the ends deeper than I did because of the water hose connection angles from the cylinder banks to the radiator. Hmmm... May have to rethink this one again. Our radiator hose tube sticks straight out the back.

Lastly, I may need some help. This is a picture of a Hisso fuel pump. My engine does not have one and I have no idea where to get one. This picture came from Kermit Weeks collection too. I suspect they are as hard to find as an honest politician. I plan on modifying an old Pesco fuel pump but I would sure like to find an original. Anyone know where to find one? I think there is a Hispano Suiza car club somewhere.

Another option is to adapt a modern automotive fuel pump which is OK to me. But finding a rotary pump is difficult. Most fuel pumps are lever actuated from a cam lobe. I need one that is gear driven. Anyone have ideas here?



Tuesday, December 21, 2010


On the back of the firewall are three wooden slats. They are the same ones used in the fuel tank cradle and they serve the same function. Plus, they give some stiffness to the upper part of the firewall itself.

Here are the slats in place. They will get a felt strip attached later.

The firewall was trimmed and the upper flange riveted last night.

The slats on the fuel tank cradle are attached to the steel straps by machine screws and nuts. Unfortunately, these screws stick out far enough to make contact with the firewall. I don't know why, but that's the way Curtiss designed it. So, we did the same thing.

Bumps had to be made to accommodate the screws. There may be some more sophisticated way to make them, but I used a ball peen hammer as the form. Just strike it with another metal hammer to stretch the metal.

Just work it slowly and angle the ball peen end to get the desired radius.

It works really well. It seems like a few whacks and the bump would be formed, but it takes longer than that. This is galvanized steel, remember?

The bottom lip of the firewall was bent to shape, too.

Here's a lousy picture of it. Time to change batteries in my camera.

Pretty productive day!



Tuesday, December 14, 2010

Station 3 cross brace

Everything was masked for paint today.

And sprayed gloss black.

And the other side too.

The firewall was reinstalled for final fitting and trimming.

Also sanded the remaining four wing struts in preparation for the application of the copper. Not a bad day!

I asked Ben Douglas of Doveworks Foundry to make another set of Jenny castings for Phil Mintari's friend. The castings were very well done and I was pleased with the results. I would highly recommend Ben's work.

More soon


Monday, December 13, 2010

Engine Bearer Brackets

After a trip to Aircraft Spruce, I got the long 5/16 in. bolts needed to assemble the center section. The Jenny has a stagger of 16 inches between the leading edge of the bottom wing and the leading edge of the top wing. Just from this trial fit, I figured out the center section has to lean forward another 2 inches. That adjustment will happen the next time I have help at the shop. Installing the center section is not a one person job!

Today the lower engine bearer support holes were drilled.

Here's the bracket in place.

While the drill was handy, holes were drilled for the eyebolts.

A wrapped cable will connect this eyebolt to the lower Station 3 fitting.

Also drilled the front engine bearer holes.

More soon. Enjoy!


Thursday, December 09, 2010

Station 3 drilling

Had a few spare minutes last night so we decided to drill Station 3.

Last year, Ken Rovie was kind enough to give me his drilling jig. Ken and his group built that neat Jenny replica hanging in the museum in St. Cloud MN. Anyway, here is a picture of the jig.

We measured everything and put the jig in place.

Drilled with the 1/4 in. long drill bit.

After that was done, Brian finished building the brackets which go under Station 3.

Since the bead blaster was unoccupied, I blasted this neat original Curtiss cable guide. It goes on the upper wing to guide the aileron cable. Pretty neat seeing a nasty old original part usable again.

John Gaertner is nearly done with the fuel gauge. The needle has to be painted black yet.

He also built the lower tank support. This was originally a casting but since the Hisso Jenny fuel tank sits vertically, we needed to make a new piece.

More soon.