Gregg Brightwell

Gregg Brightwell

Well Known Member
Ok all....

I haven't seen anything posted on this in quite a while, and I would like some info on doing this mod when it comes time to do so. The posts I have read are from distant past, but if I understand correctly, the bulkheads, and topskin needed can be ordered from Harmon? ?
I LOVE the look of the fastback, and am confident I could do the mod, (with input from those that have been there, done that being greatly appreciated). I can't see it being cost prohibitive, but then again, I have no idea.
What kind of performance changes could REALISTICALY be expected? 5 kts or more? That would be worth it. 10 kts? WOOHOO!!
Will the stock -4 tail work, or what mods are required around the lower vertical to accomodate the new top skin?
I know there are several out there who have done this... Please share your experiences....

Thanks!


Gregg Brightwell
Independence, KS
-4, ordering wings
 
I will have some answers for you soon. I too have not found much information. The parts required cost about $300 (including S&H) I looked at it on the plane for a few hours. Some of the changes that will have to be made are:

-Cutting the upper bulkhead. They seem too narrow.
-Figure out how high to make the turtle deck (behind the rear seat). This is a chicken or egg problem for me. I don't have the canopy installed nor know the height at that location.
-I will just buy a rocket emp fairing. The Vertical stab will have to be modified to fit with the new turtle deck angle. Or maybe cut a hole on the turtle deck.
-Figure out a support for the aft part of the canopy

There are other things to do but those seem to be the biggest ones. As far as speed gains, I have no clue. I just like the look. My RV-8 is also getting the same mode. I purchased it from Showplanes.
 
I have heard that you get a 5 kt speed gain by going to the fastback. Was going to do it on the RV-4 I am building, but since its probably going to be sold, decided to keep it mostly stock.
 
Fastback Conversion Info

Gregg,

Look for my info in the forum titled "Fastback Conversion" posted on 6-29-06 at 6:36pm. It's got the info and pics to back up the Harmon Turtledeck conversion.

Don't bother with the Rocket empennage fairing. It is thick and very heavy. I had the new (light green) fairing from Van's and with a bit of work it fit better.

Yes, the very bottom-front of the VS will need to be cut to fit the slightly higher and angled TD.

I also bought the canopy aft metal tubing from John (he'll make whatever you want). It's a step up in tubing diameter, so make sure you get the horizontal tubes long enough to extend to the canopy cross-over bar. You can then simply cut off Van's bars and weld on John's. The bottom angle can be spliced anywhere along it's length. Once this is done you can spread the single horizontal bar that sets right at the baggage bulkhead that angles backward and splice it to fit.

Let me know if you have any more questions or need more photos.
 
It will be no harder to build the fast back using the harmon parts than it will be to build a stock RV4. When it comes to the canopy that job will be easier as the rear skirts on the RV4 are harder to do right then the skirts that match the raised turtle deck.
Do not rivet on the new upper bulkheads until the new turtle deck is clecoed in place. This way the bulkheads can be "moved" in or out, and up or down to match the skin. Little doublers can be riveted in place at that time to hold the upper bulkheads to the old lower bulkheads and also at the very top centre of the bulkheads. Always remember it is easier to make the bulkhead fit the skin than it is to make the skin fit the bulkheads.
 
good info

I want to thank you all for the input. FWIW, I conversed via email with John Harmon today, and the bulkheads and skin can be readily purchased from him. He said it will also require a canopy from Todd's. No big deal, I can just short that from vans finishing kit when I get there....right?

Thanks again..

Gregg J Brightwell
Independence, KS
 
planedriver26 said:
I want to thank you all for the input. FWIW, I conversed via email with John Harmon today, and the bulkheads and skin can be readily purchased from him. He said it will also require a canopy from Todd's. No big deal, I can just short that from vans finishing kit when I get there....right?

Thanks again..

Gregg J Brightwell
Independence, KS
Click to expand...

:mad::eek: They did not tell me I needed at Todd's canopy. I already have mine from Vans. I asked if I needed a different canopy and they told me NO.
 
Canopies and Such...

Yes, you really do need a different canopy. The back of the stock canopy is too narrow and short to work with the widened and taller part of the Harmon turtledeck. I worked with Todd to get a really good shape and fit for this conversion. If you tell him to make the same canopy he made for me, I'm sure he can come up with what you need. Another thing, make sure you go with the 1/4" thick material as his material draw down is so much that the sides can get a bit thin!

Good luck!
 
How much is the rocket canopy? I look on Todd's web site but could not find the price.
 
Canopy Cost

Paperwork from Todd was minimal....I can't seem to find a receipt, but I believe the cost was about $350 - 400 with his usual half price replacement deal if you need a second one due to breakage.

Good Luck!
 
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