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"
- Name: Brian Karli
- Location: Peachtree City, Georgia, United States
Tuesday, November 20, 2007
Monday, November 19, 2007
Lower longeron taper and splice
Having a second set of hands, I decided to tackle the twenty-something-foot lower longerons.
Here's Nate at the table saw rough cutting the front longeron to size.
The front half of the longeron is 1 1/2in. wide at the front and tapers to 1 1/4in. at the end. I used the "ever so handy" oscillating spindle sander to fine tune the taper.
Then the ends were put into the splice jig.
Here Nate checks the front and back taper cuts prior to gluing.
Of course Brighton had to help dad in the shop. No, the saw is not plugged in. Yes, I am watching him so he does not touch the sharp blade.
While the splices were glued, clamped and drying, Nate and I decided to experiment with the art of cable wrapping. We took a thimble with some 1 x 19 cable and wrapped some galvanized wire around the end.
Then we heated the area with a big iron and tried to ease some solder into the cracks. It was a frustrating experience! The solder didn't flow very well.
Fellow Jenny restorer Paul Dougherty had given me some good advice. He told me to heat the oil out of the cable with a low heat from a Bernsamatic torch. That seemed to help.
But the solder still didn't flow all that well and I was stumped.
Fellow Bucker friend Steve Beaver told me to use a different type of flux. He explained that I had used electrical flux rather than and plumbers flux and there was a big difference. Plumbers flux has more acid and cleans better. Electrical flux is milder because electronic devices use copper and the milder flux keeps the corrosion to a minimum. I'm going to try this next time.
Here is an original wire at the top and our "goof-off" try below. I'm also going to use a bigger thimble next time.
Nate giving his approval. We better get good at this - there's only a few dozen more ends to solder!
Till next time
Sunday, November 18, 2007
Station 4 & 5 Spar Carry through
I has the ends milled a few months ago and the wire bracket water-jet cut before that, so buying the tubing and threaded rod was the last step in the process. These tubes carry the load between the two lower wings.
The tubes are hefty - 1 1/2 in wide and .065 thick. Plus, there is a threaded rod in the tube holding the ends in place. I used 7/16 rod with fine cut threads purchased at MSC. Lastly, there is a collar behind the wire bracket. Originally, this collar and bracket were one piece - pressed I imagined. I decided to make them out of two pieces. In this case, it's 1 3/8 tubing .120 thick.
The entire thing is then brazed together. Pretty neat. Tomorrow I hope to set them in place.
Wednesday, November 14, 2007
Now - the fittings are sloped forward. The cabane struts attach on the top part of the fitting. The vertical brace (shown here) attach on the lower half between the longerons. They slope rearward.
Where do you measure the distance between stations? Center of the fitting? Center of the vertical strut? It's a pretty critical measurement, remember?
Several Curtiss drawings list the distances between stations. I poured over these drawings for a long time. None of them were specific. But finally, I found the answer. One drawing had a small notation, smudged and obscure, but readable. The distance between station4 and station 5 is measured between bolt centers. Ah ha! That makes sense.
That being discovered, I put stations 2,3,4,5 in place. Here's how I ended up drilling the holes. This picture shows Station 2. After measuring, remeasuring and measuring one more time, the fitting was set in place and my handy drilling jig was used. Advice - get the long drill bits. They work better!
Next step is fitting, tapering and splicing the lower longeron. I set the longeron in place for a trial fit. I wanted to see how close my bending jig came to the real fuselage. Not too badly. Only a bit of tweaking is in order. It's pretty close.
More early next week. Until then.....enjoy
Friday, November 09, 2007
fuselage hard wires
My friend Dave Daugherty came by the shop and helped build some wires. His son Carter (on the table) and my youngest son Brighton (checking the air compressor hose) supervised.
Here's a shot of the progress. Note - when you're making the wires, the natural curve from the coiled roll tends to pull the vertical pieces towards you. This ruins all the time you spent trying to keep the structure nice and square! So to combat this, I made a fixed brace on the first vertical. That gave me something to pull against. Now, when you make wires, you can take the slack out of the wire by tightening the turnbuckle without moving the vertical piece.
From the other side.
More wires to come soon!