Transformation of my RV-4 to a fastback
For the 18th birthday of N44TK I gave her a little face lift.
I admired Dave Anders RV-4 fastback conversion, done many years ago, and liked the appearance. I know that the Bakersfield area has a number of -4 fastbacks and there have been a number of -4s built from the beginning as a fastback around the country. I never discussed with anyone the process that they had gone through in the conversion of a completed -4. At the end of 2009 I decided I would make some work for myself after completing an RV-12 (N124RN) that was sold and made its first flight Dec 2/09.
I did speak with Axel Alvarez about his -4 build this last fall and followed a few of his suggestions. I basically made the frame fit the Harmon Rocket bubble. I removed all the original 7/16 inch tubing from Van's canopy frame and removed all but about 6 inches of the 3/4 inch square tubing on each side at the rear of the canopy. The major tube bending at the rear of the plexi can be done without any special tubing bender. The sides required nothing special to make them fit the remainder of the frame.
The costs involved, amounting to about $1,800, excluding repaint are as follows:
- 3 bulkheads and a turtledeck skin from John Harm - cost delivered $256
- Harmon Rocket canopy from Todd's Canopies, Florida - delivered $650
- Van's RV-4 canopy frame - $308
- Van's RV-8 empennage fairing (Fits nearly perfectly) - $91
- New 7/16 inch 6061 tubing (16 feet)-$60
- welding cost after modifying Van's frame - $110
- miscellaneous costs (not including repaint) - $300
The process turned out to not be too daunting, but it did keep my airplane down for about 90 days this winter.
The canopy is approximately 4 inches forward of a regular canopy. I chose to do the sides out of .025 aluminum and the front and rear out of epoxy. All of this was fairly simple.
My first flight after completion was March 5, 2010 and was uneventful. I noticed no difference in the handling as a result of the aerodynamics. There was a slightly different sound in flight.
I was not the original builder of N44TK, but was intimately involved since it's inception. I was the mentor to my friend Tom Karren, deceased in February 2008, who enjoyed the airplane from February 1992, until about 1 1/2 years before his death. I completed my first RV-4 (N504JT) in July 1988 and sold it in 2003 after flying it for 14 years and 1,400 hours, following completion of an RV-9A. I purchased N44TK from the estate in March 2008. The -9A was sold and delivered to Yankton, SD in May 2008.
Besides the previously mentioned aircraft, I have built an RV-6A with a partner, first flown in early '90s, an RV-7 completed in 2007, after flying off 29 hours locally, I delivered the -7 to Grady's paint shop in Texas for the owner was working in China, and I also built a number of wings (non-prepunched) in earlier years for other builders.
I decided to go back to the RV-4, while owning the -9A, since a lot of my flying is alone, and the tandem configuration is the best for the pilot. My wife also does not mind the rear seat. After over 2,000 hours in RVs, I still enjoy them a lot. The visibility from the rear seat on the fastback is considerably better due to dropping the side skins several inches.
Attached is a link to some photos showing some of the transition. The photos are not in a proper sequence.
http://picasaweb.google.com/jaknjoan/20100305FinishOfFastBack3510#
Jake Thiessen
Independence, OR.
