Van's Air Force
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RV-4 info for purching
- Thread starter sprayers
- Start date
gmcjetpilot
Well Known Member
Good Luck, get the check book, buyer beware
Not sure what the exact question is, but like any aircraft purchase there are things you want to assure. I found this reference from Van's web site.
http://www.vansaircraft.com/pdf/usedrvkit.pdf
http://www.vansaircraft.com/pdf/sb97-05-1.pdf
http://www.vansaircraft.com/pdf/sb96-12-1.pdf
All RV's have similar things in common with any plane, Engine, prop, brakes, tires, lights, battery, instruments and avionics. Any A&P or AI should be able to inspect the engine, prop, electrical, log books and general condition. As far as the airframe I suggest getting an experienced RV pilot/builder to inspect it and fly it. This will give you an idea of how the plane fly?s and how well built it is. Remember AD's may not be complied with since it is an experimental. Many Lycoming have oil pump, magneto and crank AD's, to name a few.
WARNING, these are amateur built kit planes and may not meet any standards of construction. The RV-4 may be one of the better deals in the RV market, a good one will go for $50,000 to $60,000 or more. If you think you can buy a nice flying RV-4 for $30,000 you should think again. Sadly those days are gone. If it is that cheap I would be wary. If it is a nice (nice = good fit and finish) basic VFR 150HP, fixed prop RV-4 expect to pay at least $40,000. If it has 180hp and constant speed prop and full instruments and lights it might be double. Most will fall in between.
You did not mention your back ground, but if you have owned, maintained and operated piston planes before your experience will serve you well. The problem is finding them for sale, since good ones are not on the market too often. If they are nice they will be expenisve. Other RV models have gone for well over $100,000.
Good Luck. George
Not sure what the exact question is, but like any aircraft purchase there are things you want to assure. I found this reference from Van's web site.
http://www.vansaircraft.com/pdf/usedrvkit.pdf
http://www.vansaircraft.com/pdf/sb97-05-1.pdf
http://www.vansaircraft.com/pdf/sb96-12-1.pdf
-Call Van's for more info in general and about a specific RV-4
-Older RV-4's had 0.20 skins on the elevator, which tend to crack. Went to 0.32
-Older RV-4's, some engine mount firewall fittings cracked and the design was revised
-Later Gear legs are longer, requires a new engine mount as well as legs
-Look inside of tanks for loose sloshing compound
-Look for fuel leaks of any kind
-Rear spar bolt edge margin
-Older RV-4's had 0.20 skins on the elevator, which tend to crack. Went to 0.32
-Older RV-4's, some engine mount firewall fittings cracked and the design was revised
-Later Gear legs are longer, requires a new engine mount as well as legs
-Look inside of tanks for loose sloshing compound
-Look for fuel leaks of any kind
-Rear spar bolt edge margin
All RV's have similar things in common with any plane, Engine, prop, brakes, tires, lights, battery, instruments and avionics. Any A&P or AI should be able to inspect the engine, prop, electrical, log books and general condition. As far as the airframe I suggest getting an experienced RV pilot/builder to inspect it and fly it. This will give you an idea of how the plane fly?s and how well built it is. Remember AD's may not be complied with since it is an experimental. Many Lycoming have oil pump, magneto and crank AD's, to name a few.
WARNING, these are amateur built kit planes and may not meet any standards of construction. The RV-4 may be one of the better deals in the RV market, a good one will go for $50,000 to $60,000 or more. If you think you can buy a nice flying RV-4 for $30,000 you should think again. Sadly those days are gone. If it is that cheap I would be wary. If it is a nice (nice = good fit and finish) basic VFR 150HP, fixed prop RV-4 expect to pay at least $40,000. If it has 180hp and constant speed prop and full instruments and lights it might be double. Most will fall in between.
You did not mention your back ground, but if you have owned, maintained and operated piston planes before your experience will serve you well. The problem is finding them for sale, since good ones are not on the market too often. If they are nice they will be expenisve. Other RV models have gone for well over $100,000.
Good Luck. George
Last edited:
more....
Just to amplify a few things that George said.
The elevator and rudder skins are .016. They have a tendency to crack. Seems to be more pronounced on the high HP airplanes. I rebuilt my elevators with .020 skins as I thought this would be needed eventually. I then went out and bought a 160hp wood prop -4 with .016 skins that has had no cracks in almost 900 hrs (go figure).
The engine mounts in the early airplanes had a tendency to crack. There's a series of angles inside the fuse where the engine bolts through the mount and the angle ties the mount into the fuselage longerons. Van's came out with a change to the angle (thicker). Definately worth a look. Cracked mounts are often thought to be an inidcation that the owner is landing hard. This may or may not be true. I'm not convinced one way or the other.
Slosh. A new set of tanks is about $1700 from Evan Johnson. The slosh was a gooey coating that can peel off and plug fuel lines etc. If you look in the tanks and see aluminum, you're good. If not, you need to investigate further. Sloshed tanks were a buy/walk away item for me. Also, be aware that there were at least 3 different materials used over the years to slosh. Only the gooey one is harmful.
Most of the early airplanes had no air filter of any kind. This was common at the time but somewhat shocking if you have no experience with it. The FAB airbox kit is about $200 from Van's but requires some FG work. Carb heat is generally just a flipper which allows the engine to breath engine compartment air. Early airplanes also do not typically have a full swivel tailwheel (another $200).
How does it fly ? Will it fly hands off in calm air. Will a 160hp airplane do 150-160kts + ? Will it do it on 8gph or less ? If not, something's up. How much does it weigh empty ? Heavy airplanes can feel substantially different from light ones.
Lastly, you should think about maintainability and resale value. A hyper-translucent multi color flame job might look cool now, but how are you going to feel about it in a year ? How will a potential buyer feel about it ? Similarly, a super hyped up engine might seem cool now, but who's going to work on it ? Will you be able to sell it after a potential buyer has it inspected ?
As George pointed out, the value of these airplanes is great right now. As the market shifts towards the latest/greatest and most powerful, a nice 4 can be had for 1/2 the price of a typcial RV-8. But hey, let's keep that to ourselves
.
Good luck.
John
Just to amplify a few things that George said.
The elevator and rudder skins are .016. They have a tendency to crack. Seems to be more pronounced on the high HP airplanes. I rebuilt my elevators with .020 skins as I thought this would be needed eventually. I then went out and bought a 160hp wood prop -4 with .016 skins that has had no cracks in almost 900 hrs (go figure).
The engine mounts in the early airplanes had a tendency to crack. There's a series of angles inside the fuse where the engine bolts through the mount and the angle ties the mount into the fuselage longerons. Van's came out with a change to the angle (thicker). Definately worth a look. Cracked mounts are often thought to be an inidcation that the owner is landing hard. This may or may not be true. I'm not convinced one way or the other.
Slosh. A new set of tanks is about $1700 from Evan Johnson. The slosh was a gooey coating that can peel off and plug fuel lines etc. If you look in the tanks and see aluminum, you're good. If not, you need to investigate further. Sloshed tanks were a buy/walk away item for me. Also, be aware that there were at least 3 different materials used over the years to slosh. Only the gooey one is harmful.
Most of the early airplanes had no air filter of any kind. This was common at the time but somewhat shocking if you have no experience with it. The FAB airbox kit is about $200 from Van's but requires some FG work. Carb heat is generally just a flipper which allows the engine to breath engine compartment air. Early airplanes also do not typically have a full swivel tailwheel (another $200).
How does it fly ? Will it fly hands off in calm air. Will a 160hp airplane do 150-160kts + ? Will it do it on 8gph or less ? If not, something's up. How much does it weigh empty ? Heavy airplanes can feel substantially different from light ones.
Lastly, you should think about maintainability and resale value. A hyper-translucent multi color flame job might look cool now, but how are you going to feel about it in a year ? How will a potential buyer feel about it ? Similarly, a super hyped up engine might seem cool now, but who's going to work on it ? Will you be able to sell it after a potential buyer has it inspected ?
As George pointed out, the value of these airplanes is great right now. As the market shifts towards the latest/greatest and most powerful, a nice 4 can be had for 1/2 the price of a typcial RV-8. But hey, let's keep that to ourselves
.Good luck.
John
As a current 4 builder, I'd say get an RV builder to go with you before laying down the cash. I like to think that as a lifelong gear-head I've got a good eye for quality workmanship, but before building this plane I just wouldn't have known what to look for. Fancy paint, upholstery and instruments are something anybody can buy, but it's the little things that would indicate true craftsmanship. Uniform rivet spacing, clean fiberglass work, well arranged panel, great cowl and canopy fit, tidy and well thought out wiring runs are just a few of the things that the truly obsessive builder will take care with. These are indicators that the stuff you can't see was also done properly.
Steve Zicree
RV4 finishing (Geez, when is this "finishing" going to be finished?)
Steve Zicree
RV4 finishing (Geez, when is this "finishing" going to be finished?)
Good points made
George was right on the spot except for his RV-4 with the .032 elevator skins weighs a ton (Sorry George, I couldn't resist.) I think the elevator skin cracking has been alleviated in later airplanes with the use of RTV in the trailing edges. I'm glad that the guys mentioned the slosh in the tanks and (thanks George) that rear spar edge distance. These folks all made very good points. Good luck.
George was right on the spot except for his RV-4 with the .032 elevator skins weighs a ton
(Sorry George, I couldn't resist.) I think the elevator skin cracking has been alleviated in later airplanes with the use of RTV in the trailing edges. I'm glad that the guys mentioned the slosh in the tanks and (thanks George) that rear spar edge distance. These folks all made very good points. Good luck.more
http://www.evansaviationproducts.com/
One point on the rear spar edge distance. I think this is a red-herring. The idea of checking this goes back to the very first RV-3 wing failure. The FAA concluded that the wing failed at the rear spar and then overloaded the front spar causing the wing separation. In retrospect, it is almost certain that the opposite happened. This conclusion sent Van on a mission to get everybody verifying the rear spar bolt edge distance to insure it wouldn't fail under normal loads. The whole scenario was extremely unfortunate in that it delayed the eventual determination of the wing problems. My opinion of course.
There's nothing wrong with checking this dimension. But there's never been a wing failure on an RV4 or RV6 (same wing) that I am aware of.
Good luck
John
http://www.evansaviationproducts.com/
One point on the rear spar edge distance. I think this is a red-herring. The idea of checking this goes back to the very first RV-3 wing failure. The FAA concluded that the wing failed at the rear spar and then overloaded the front spar causing the wing separation. In retrospect, it is almost certain that the opposite happened. This conclusion sent Van on a mission to get everybody verifying the rear spar bolt edge distance to insure it wouldn't fail under normal loads. The whole scenario was extremely unfortunate in that it delayed the eventual determination of the wing problems. My opinion of course.
There's nothing wrong with checking this dimension. But there's never been a wing failure on an RV4 or RV6 (same wing) that I am aware of.
Good luck
John
The most common reason for the .016" elevator and rudder skins cracking was that people were not bending the trailing edges sufficiently. This left a slight load on the skins when riveted to the spar. Vibration then worked on the last rivet on the stiffeners leading to cracks. Properly bent skins do not crack. My -6 has been flying more than 12 years with .016" skins and no cracks. If you find an airplane that interests you, please get a pre-purchase inspection. This will run you in the neighborhood of $400, but it is money well spent.
Mel...DAR
Mel...DAR
elev/rudder cracking
I recently replaced my original rudder skin with the .020. There were half a dozen small u-shaped cracks at the last or first rivet of a stiffener. I bent my trailing edge better this time, and agree that is what is causing the cracks, not the skin thickness.
My elevator skins are fine, and the bend is as it should be there. If there is any "bowing" toward the trailing edge, it will crack unless you have applied RTV to prevent "oil-canning" there. My rudder cracks were actually at the first rivet near the spar, before the trailing edge ones occured. I know of a -6 with elevator cracks, but no rudder cracks, and another with rudder but no elevator cracks. Go figure.
I have a 180hp -4, but don't think that is the causal factor. My cracks showed up after about 175 hours. Probably the biggest hazard in putting the proper bend in the trailing edge is bumping the end of the stiffener into the opposite side of the skin. Cut a significant angle on the stiffener, more than shown in the plans. It will still stiffen the skin fine, but won't leave memories of bending in the opposite skin.
I recently replaced my original rudder skin with the .020. There were half a dozen small u-shaped cracks at the last or first rivet of a stiffener. I bent my trailing edge better this time, and agree that is what is causing the cracks, not the skin thickness.
My elevator skins are fine, and the bend is as it should be there. If there is any "bowing" toward the trailing edge, it will crack unless you have applied RTV to prevent "oil-canning" there. My rudder cracks were actually at the first rivet near the spar, before the trailing edge ones occured. I know of a -6 with elevator cracks, but no rudder cracks, and another with rudder but no elevator cracks. Go figure.
I have a 180hp -4, but don't think that is the causal factor. My cracks showed up after about 175 hours. Probably the biggest hazard in putting the proper bend in the trailing edge is bumping the end of the stiffener into the opposite side of the skin. Cut a significant
angle on the stiffener, more than shown in the plans. It will still stiffen the skin fine, but won't leave memories of bending in the opposite skin.
