Van's Air Force
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Fastback RV-4
- Thread starter t4tango
- Start date
RV-4 conversion to a fastback
First off, I undertook a conversion of my 1992 RV-4 to a fastback two years ago, and would do it again in a heartbeat. I had my airplane down for 90 days during the process.
I purchased bulkheads 407, 408 and 409 plus the enlarged turtledeck skin from John Harmon in Bakersfield, California. Then I ordered a Harmon Rocket canopy bubble from Todd's Canopies in Florida. I purchased a new standard RV-4 canopy frame from Van's and modified it as necessary to fit the aircraft and the new turtledeck. Since there are no plans for this conversion, you just do what needs to be done to accomplish the desired outcome.
If you are interested in any of the finer details, you can contact me at <[email protected]> and I will be happy to share pictures and my experience with you.
I can't tell you the exact increased speed I gained, but I can tell you that I can fly all day at 8,500 to 9,000 feet at WOT leaned to just less than maximum EGT and show 174 kts. TAS. This is with an 0-360 carbureted Lycoming and standard Hartzell C/S prop.
I actually did the conversion for the appearance but believe the increased performance in cruise is worth it.
Jake T
First off, I undertook a conversion of my 1992 RV-4 to a fastback two years ago, and would do it again in a heartbeat. I had my airplane down for 90 days during the process.
I purchased bulkheads 407, 408 and 409 plus the enlarged turtledeck skin from John Harmon in Bakersfield, California. Then I ordered a Harmon Rocket canopy bubble from Todd's Canopies in Florida. I purchased a new standard RV-4 canopy frame from Van's and modified it as necessary to fit the aircraft and the new turtledeck. Since there are no plans for this conversion, you just do what needs to be done to accomplish the desired outcome.
If you are interested in any of the finer details, you can contact me at <[email protected]> and I will be happy to share pictures and my experience with you.
I can't tell you the exact increased speed I gained, but I can tell you that I can fly all day at 8,500 to 9,000 feet at WOT leaned to just less than maximum EGT and show 174 kts. TAS. This is with an 0-360 carbureted Lycoming and standard Hartzell C/S prop.
I actually did the conversion for the appearance but believe the increased performance in cruise is worth it.
Jake T
smokyray
Well Known Member
Fastback FOUR, the best RV ever?
Tim,
You have chosen wisely, the Fastback RV4 is arguably the best RV of any type, ever. You need only look back a few threads to AXO's very nice project and Jake's comments above to see the merits of the FRV-4.
Having flown several F4's and owned an HR2 I can tell you the speed gained and ergonomics of more back seat head room and slightly more baggage space alone make it worthwhile. Dave Anders built one of the first ones back in the mid 90's. Dave's masterpiece in horsepower vs weight and drag reduction attention to detail was the CAFE efficiency winner 15 years ago and is the fastest RV on the planet, still to this day.
Considerations would be to purchase the parts from John Harmon, then AXO, JJ and others can help you with exactly what you need.
Good call!
Dave Anders masterpiece FB RV-4
My buddy JJ's gorgeous FB-4
Smokey
Tim,
You have chosen wisely, the Fastback RV4 is arguably the best RV of any type, ever. You need only look back a few threads to AXO's very nice project and Jake's comments above to see the merits of the FRV-4.
Having flown several F4's and owned an HR2 I can tell you the speed gained and ergonomics of more back seat head room and slightly more baggage space alone make it worthwhile. Dave Anders built one of the first ones back in the mid 90's. Dave's masterpiece in horsepower vs weight and drag reduction attention to detail was the CAFE efficiency winner 15 years ago and is the fastest RV on the planet, still to this day.
Considerations would be to purchase the parts from John Harmon, then AXO, JJ and others can help you with exactly what you need.
Good call!
Dave Anders masterpiece FB RV-4
My buddy JJ's gorgeous FB-4
Smokey
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longranger
Well Known Member
I thought so too, until this morning when I read Bob Axom's post in the "best RV" thread:
I always thought the fastback conversion looked good, but these photos are fantastic, a credit to the builders thats for sure. I'm not sure whether anyone has done the conversion over here from an existing RV-4, and noted that on AXO's thread that the Harmon frames were cut and rivetted to the existing RV-4 ones which is pretty much what I will have to do to get rid of the damage - were there any issues with your EAA that I could take on board when I speak to our regulator?
smokyray
Well Known Member
FB4 price tag
Cost to an existing 4? Since Dave told me the FB mod increased cruise roughly 5 knots, figure $1000 per knot
BTW I am a skeptic when it comes to speed claims, but the CAFE foundation provides real data collected by experts and calibrated instruments. The prototype HR2 couldn't match Dave's original 4, he has changed props to a WW 151 since Cafe.
Check this out:
http://cafefoundation.org/v2/aboutcafe_orderfromchaos.php
Smokey
Cost to an existing 4? Since Dave told me the FB mod increased cruise roughly 5 knots, figure $1000 per knot
BTW I am a skeptic when it comes to speed claims, but the CAFE foundation provides real data collected by experts and calibrated instruments. The prototype HR2 couldn't match Dave's original 4, he has changed props to a WW 151 since Cafe.
Check this out:
http://cafefoundation.org/v2/aboutcafe_orderfromchaos.php
Smokey
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Tom Martin
Well Known Member
Tip for Harmon bulkheads:
Cleco the bulkheads in place with two or three clecos on the sides and at the top. I forget it they are one piece or two pieces but it they are one piece then cut the bulkheads in half at the top. In that case make a little patch to join the top halves together and hold with a few clecoes. Drill the holes for the skins in the bulkheads. Now put the skin in place and back drill and clecoe it to the #7 and the aft small bulkhead.
The next step is to take the clecoes out of the top center of the remaining two bulkheads and then drill them to the skin. After they are drilled to the skin you can then make the final holes in the patch that joins the top halves of the bulkheads together.
The point is that you want to make the bulkheads FIT THE SKIN, NOT THE SKIN FIT THE BULKHEADS. You may also have to replace some of the lower flanges on the number seven bulkhead to get it to fit the skin properly.
The Harmon bulkheads, by today's standards, could be considered a good place to start.
Cleco the bulkheads in place with two or three clecos on the sides and at the top. I forget it they are one piece or two pieces but it they are one piece then cut the bulkheads in half at the top. In that case make a little patch to join the top halves together and hold with a few clecoes. Drill the holes for the skins in the bulkheads. Now put the skin in place and back drill and clecoe it to the #7 and the aft small bulkhead.
The next step is to take the clecoes out of the top center of the remaining two bulkheads and then drill them to the skin. After they are drilled to the skin you can then make the final holes in the patch that joins the top halves of the bulkheads together.
The point is that you want to make the bulkheads FIT THE SKIN, NOT THE SKIN FIT THE BULKHEADS. You may also have to replace some of the lower flanges on the number seven bulkhead to get it to fit the skin properly.
The Harmon bulkheads, by today's standards, could be considered a good place to start.
I LOVE my RV-4FB but.....
Smoky,
Thanks for the compliment but YOU CAN'T HAVE MY -4FB!
Anyone contemplating a RV-4 fastback should realize it won't be as easy as a 'standard' RV kit. Van's takes most the quess work out of the build when you follow the plans. Most of it. Deviations, such as a fast back, different cowl, etc, creates many a head scratching moment. Case in point is the Harmon bulkheads. They are designed for the longer Harmon fuselage. So when placed in a standard -4 fuselage they must be cut, and in my case, widened to fit. This is trial and error since there are no 'plans' to follow. Furthermore, the fiberglass fairing on the tail juncture won't fit: the fast back changes the shape. Another biggie is the canopy frame. Not even close to Van's standard. And...And...And...
I made several changes on mine: Moved the front seat back 4 inches. (two weeks ago I had a 260 pound, 6'2" guy in the back, not comfortable but doable still!) Moved the canopy frame back 6 inches to give it a longer nose look, added a Sam James cowl....love the look! Etc Etc etc.
Every change you make to Van's standard will add exponentially to your build time. I hated it during the process but love the results. My plane turned out light and fast, which is purely by luck and chance since I went with looks before science. But I love my RV and it will stay with me 'forever'!
Good luck in your endeavors and most importantly, work on it a little every day and soon....nah, three years from now it will be done...or not!
Smoky,
Thanks for the compliment but YOU CAN'T HAVE MY -4FB!
Anyone contemplating a RV-4 fastback should realize it won't be as easy as a 'standard' RV kit. Van's takes most the quess work out of the build when you follow the plans. Most of it. Deviations, such as a fast back, different cowl, etc, creates many a head scratching moment. Case in point is the Harmon bulkheads. They are designed for the longer Harmon fuselage. So when placed in a standard -4 fuselage they must be cut, and in my case, widened to fit. This is trial and error since there are no 'plans' to follow. Furthermore, the fiberglass fairing on the tail juncture won't fit: the fast back changes the shape. Another biggie is the canopy frame. Not even close to Van's standard. And...And...And...
I made several changes on mine: Moved the front seat back 4 inches. (two weeks ago I had a 260 pound, 6'2" guy in the back, not comfortable but doable still!) Moved the canopy frame back 6 inches to give it a longer nose look, added a Sam James cowl....love the look! Etc Etc etc.
Every change you make to Van's standard will add exponentially to your build time. I hated it during the process but love the results. My plane turned out light and fast, which is purely by luck and chance since I went with looks before science. But I love my RV and it will stay with me 'forever'!
Good luck in your endeavors and most importantly, work on it a little every day and soon....nah, three years from now it will be done...or not!
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Attention Jim Warren, I believe
I received an email today (Dec. 18) from a gentleman with regards to a question on the conversion of my RV-4 to a fastback. The message auto-deleted before I was able to respond. This has happened a few times recently and don't know the reason.
Mr. Warren (I think was your name) please resubmit your email to me and I will be happy to share any information and/or photos that I have.
My email: [email protected]
Jake T.
I received an email today (Dec. 18) from a gentleman with regards to a question on the conversion of my RV-4 to a fastback. The message auto-deleted before I was able to respond. This has happened a few times recently and don't know the reason.
Mr. Warren (I think was your name) please resubmit your email to me and I will be happy to share any information and/or photos that I have.
My email: [email protected]
Jake T.
FB RV4 conversion
I had also been thinking about doing this - not for speed but for looks mainly - nice to see that you can also get some speed increase as well. I was thinking of also doing the long gear - for that harmon rocket look as well. Here's my RV4. Thanks for posting this informaiton - good stuff I was wondering if anyone had thought of doing this - bit cheaper then the alternative of buying or building a full - harmon rocket kit. I got mine farily cheap from the US about a year ago - spent quite a bit fixing it up to meet Canadian Transport Canada standards so I could get a certificate of airworthiness here. Did some minor - touch ups here and there. Next I would like to add 160HP cylinder upgrade - from titan or Lycoming - do the fastback - and canopy modifications - add the longer gear and do a full repaint - to Orange with some black accecents. Bit of work all and all. Just for fun mostly - as it's not too bad as it is. I added the checkers to give it that aerobatic plane look since I do quite a bit of aerobatics in this plane. Sorry I have not yet figured out how to put the photo of mine on there! I can email it to someone though if someone would like to see it. It's red mostly - with checkered tips and on the rudder.
I had also been thinking about doing this - not for speed but for looks mainly - nice to see that you can also get some speed increase as well. I was thinking of also doing the long gear - for that harmon rocket look as well. Here's my RV4. Thanks for posting this informaiton - good stuff I was wondering if anyone had thought of doing this - bit cheaper then the alternative of buying or building a full - harmon rocket kit. I got mine farily cheap from the US about a year ago - spent quite a bit fixing it up to meet Canadian Transport Canada standards so I could get a certificate of airworthiness here. Did some minor - touch ups here and there. Next I would like to add 160HP cylinder upgrade - from titan or Lycoming - do the fastback - and canopy modifications - add the longer gear and do a full repaint - to Orange with some black accecents. Bit of work all and all. Just for fun mostly - as it's not too bad as it is. I added the checkers to give it that aerobatic plane look since I do quite a bit of aerobatics in this plane. Sorry I have not yet figured out how to put the photo of mine on there! I can email it to someone though if someone would like to see it. It's red mostly - with checkered tips and on the rudder.
islandmonkey
Well Known Member
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Jerry Wilcox
Member
rv4 Fastback
I'm converting a 4 to a fastback, decided to make my own bulkheads and have these cardboard templates from the job. It takes a considerable bit of time to come up with these and I hate to just throw them in the trash. They may not be exactly what someone else would want but are a great starting point if anyone wants them for the price of postage they yours.
Jerry
I'm converting a 4 to a fastback, decided to make my own bulkheads and have these cardboard templates from the job. It takes a considerable bit of time to come up with these and I hate to just throw them in the trash. They may not be exactly what someone else would want but are a great starting point if anyone wants them for the price of postage they yours.
Jerry
LifeofReiley
Well Known Member
I'm converting a 4 to a fastback, decided to make my own bulkheads and have these cardboard templates from the job. It takes a considerable bit of time to come up with these and I hate to just throw them in the trash. They may not be exactly what someone else would want but are a great starting point if anyone wants them for the price of postage they yours.
Jerry
I'll take 'em Jerry.
Gregg Brightwell
Well Known Member
Dang beat me to it!!
When YOU get done I'll take em!!
Gregg
When YOU get done I'll take em!!
Gregg
Jerry Wilcox
Member
Fastback 4
Shop's a mess but thought i post this photo of progress on the fastback 4. Glad to be getting closer to being finished.
Jerry
Shop's a mess but thought i post this photo of progress on the fastback 4. Glad to be getting closer to being finished.
Jerry
Michael White
Well Known Member
Lookin' good, Jerry!
LifeofReiley
Well Known Member
Jerry Wilcox
Member
fastback4
Thanks for the comments guy's, I'm happy with the way it's going and hope to have it back on the flight line this summer.
The Champ in the garage is I believe a 7DC which means it has a few extra horses and a larger fin area. I've had a welding approval with my maintenance licence for several years and this Champ needs some new tubing in the belly and tail, got to get at it I need the space.
Jerry
Thanks for the comments guy's, I'm happy with the way it's going and hope to have it back on the flight line this summer.
The Champ in the garage is I believe a 7DC which means it has a few extra horses and a larger fin area. I've had a welding approval with my maintenance licence for several years and this Champ needs some new tubing in the belly and tail, got to get at it I need the space.
Jerry
Paul Tuttle
Well Known Member
Jerry,
Is that the -4 that was in the Hangar up at Wayman? It's looking good!
Is that the -4 that was in the Hangar up at Wayman? It's looking good!
Jerry Wilcox
Member
Weyman rv4
Paul
Yes this is the 4 from Weyman. It was built in the mid 80's in western Canada. It's gone from a spruce it up paint job to a complete rebuild nose to tail.
Jerry
Paul
Yes this is the 4 from Weyman. It was built in the mid 80's in western Canada. It's gone from a spruce it up paint job to a complete rebuild nose to tail.
Jerry
