Looking for RV-3 RV-4 Midget Mustang firewall or cowling blueprints or detail measurements. I?m trying to find out if any of these cowlings could be used on a different aircraft (one off experimental). If they are close, maybe it can be modified to work on this project. Thanks
Van's Air Force
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Wanted - RV3 Midget Mustang firewall blueprint measurements
- Thread starter andyg
- Start date
gmcjetpilot
Well Known Member
Which one? RV-3 or Midget Mustang? I am trying to envision my old RV-4 plans I don't have anymore. I don't recall the plans having detailed measurements, cross sections, you could build a cowl from. You would be best looking at an actual RV-4 and taking measurements, or may be buy an old RV 4 cowl collecting dust somewhere to modify maybe.
There is the pure original method of wrapping the engine in plastic, securing foam blocks all over and carving in place (Tony Bingelis books I think firewall forward recommended).
Of course there is James Aircraft, faster way to go than DIY for both RV-4 or Mustang II cowl. They currently go for $1400 + $550 for the plenum....
https://www.jamesaircraft.com/products/rv-4/
Van's older cowls were heavy vinyl ester, solid layup no core, gel coat tended to crack, and prone to shrink a little with age.
Good luck with the project.
There is the pure original method of wrapping the engine in plastic, securing foam blocks all over and carving in place (Tony Bingelis books I think firewall forward recommended).
Of course there is James Aircraft, faster way to go than DIY for both RV-4 or Mustang II cowl. They currently go for $1400 + $550 for the plenum....
https://www.jamesaircraft.com/products/rv-4/
Van's older cowls were heavy vinyl ester, solid layup no core, gel coat tended to crack, and prone to shrink a little with age.
Good luck with the project.
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gmcjetpilot
Well Known Member
Some pictures of this custom plane with measurements would be great.
Do you plan on making the cowl out of metal?
If the inlet is what you want to modify you could make a fiberglass nose bowl and attach to the existing metal cowl (classic design).
You want to buy a cowl and cut to fit?
Tony Bingelis has a series of books (3 or 4 books), one shows how to make your own cowl from fiberglass, no plans required. Recommend you buy these books. The idea he presents in detail with photos is you make cowl right on the airplane. You wrap the engine and cover everything (engine mount, firewall) with plastic to protect it. You take foam blocks and surround the engine from firewall to prop. You glue smaller pieces of foam together as needed to get the rough shape of cowl. Then you start to shape it like a sculpture. You cover in fiberglass. You split the glass along the sides and remove the foam. You finish the cowl and attachments to firewall. There you go a custom cowl for custom one off airplane. It is a lot of work but it would be a great learning experience. If glass work is not your thing, Youtube has some good videos and Sam James has a how to DVD.
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David Paule
Well Known Member
You can buy the RV-3 plans on thumb drive. They contain the firewall outline but not the shape of the small cheek bulkheads, as best as I remember.
Dave
Dave
gmcjetpilot
Well Known Member
First - of all that is a gorgeous little single seater. You MUST give us all the history, specs and performance if you have flown it. I looked it up, it is a RITER SPECIAL, serial 101 built in 1961!!!! At one time it was in AIR & MILITARY MUSEUM OF THE OZARKS. This is a classic. I would not change it. Recommend you fly it stock first and get CHT's from all 4 jugs before making cooling changes. My question is the cowl looks great. What is your motive to change it?
Second - Wheel Pants and Gear Leg Fairings - What I see of cowl, pretty, classic design, fairly efficient. I wouldn't screw with it. If you are trying to gain another 5 mph the wheel pants and gear leg fairings would be your first choice. I will repeat a few times... leave this old gal alone. It is so classic. It was frankly ahead of it's time. Nothing wrong with the wheel and gear fairings. It looks robust with better soft field gear and wheel fairings than RV's, which are made more for speed.
Third - Induction scoop and airbox - if you MUST screw with cowl start with the intake, install a VAN's style intake or FAB (filtered airbox) and scoop. This may not pick up speed but it will increase your MAP and HP in cruise. Also new exhaust, 4-into-1 or 4-into-4. I see "Y" pipes from the pictures, not as good for making the most HP. Increase HP increases speed. The stock inlet area is clearly a bit large, but design looks very good. The air intake lip looks sharp, but again my suggestion is leave it original like a classic car.... Looking at the picture it may already have an efficient Van's style airbox on it....
Fourth - Sealed solid plenum - Before you reduce the cowl inlet cooling area (fly with it stock and record CHT's) consider leaving the cowl alone and making a sealed solid plenum (verses soft seals against cowl). Many RV flyers have done this beautifully. This will pick up a few MPH and improve cooling. This will keep classic look and improve cooling. You can block off exit air if cooling is good and cut drag a little more. Love the look of the original cowl.
Fifth - Reduce cooling inlets area and improve design - Frankly this original design deserves to have classic original work, but if you must change the cowl you MUST (in my opinion) do the plenum at the same time. Just changing the shape, area of the cooling inlets will not help anything and may cause cooling issues. Why make a new cowl? Just modify this one.
Cowl Cooling Inlets - I would leave the cowl alone but if I was to change the inlets I would just mod the existing cowl. The topic of how and what to do is long. I assume this is a stock O320 or O360. About 24" sq inch for two inlets is about right (4" diameter round). Why round, well it has too advantages. It is easier to seal to the solid plenum with a circular soft duct that can be clamped down; and you want to move the inlets as far outboard as possible to get into clean prop are. Near the hub the air get's beat to death. However as I say in 4th item you can adapt the existing inlet shape to the solid sealed plenum, but it takes a little more creativity. It has been done before and done nicely by many RV builders....
Changing inlet areas to smaller size and making it more efficient will lower drag. KEY WORDS more efficient. How much does this change make? 5 mph with the plenum may be. It may make CHT's get a little warmer (may be), so I'd fly with existing set up and monitor all four CHT's first. Make sure a solid plenum is sealed to cowl inlets absolutely, a must. To just make smaller inlets and do nothing else is not a great idea. Poor inlet transition, poor pressure recovery, air leaks of inlet air to baffling is drag and loss of efficiency.
Typically ROUND is the way to go for simplicity and some aerodynamic reasons. Two 4" round inlets would be enough. You might go smaller but that is up to you. The inlet should have generous lip radius and the throat of inlet curved, like the top of an airfoil... where it diverges from front to back, gets larger towards the plenum. Round inlets would be MODERN on this beauty and look out of place. This plane has other drag issues, and at some point leave it and go fly. I think you should build an RV-3 or RV-4
If you are going hog wild you may want to add a prop extension. This will move prop out and allow you to make the cowl nose bowl more aerodynamic and allow room for good cooling inlet transition.
Changing inlet areas to smaller size and making it more efficient will lower drag. KEY WORDS more efficient. How much does this change make? 5 mph with the plenum may be. It may make CHT's get a little warmer (may be), so I'd fly with existing set up and monitor all four CHT's first. Make sure a solid plenum is sealed to cowl inlets absolutely, a must. To just make smaller inlets and do nothing else is not a great idea. Poor inlet transition, poor pressure recovery, air leaks of inlet air to baffling is drag and loss of efficiency.
Typically ROUND is the way to go for simplicity and some aerodynamic reasons. Two 4" round inlets would be enough. You might go smaller but that is up to you. The inlet should have generous lip radius and the throat of inlet curved, like the top of an airfoil... where it diverges from front to back, gets larger towards the plenum. Round inlets would be MODERN on this beauty and look out of place. This plane has other drag issues, and at some point leave it and go fly. I think you should build an RV-3 or RV-4
If you are going hog wild you may want to add a prop extension. This will move prop out and allow you to make the cowl nose bowl more aerodynamic and allow room for good cooling inlet transition.
You could fly this and buy a used RV-3 or RV-4 fix-er-upper and experiment on that, but this old classic deserves to be preserved as is IMHO. Will going 5 or 10 MPH faster make you happier. It will still be slower than a stock RV-3 or RV-4. The RV-3 and RV-4 I'm also estimating will have shorter takeoff and landing distance and better climb rate. A cowl change will not make it an RV.
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Well you think so?
Gosh where do I begin.
Once I move to writing I don't see the post so I'll just give you a little run down of it, but may not answer many questions you asked. When I can get to a printer to print out the above post, you'll get a much better reply.
My motivation WAS to make it look a little better and a little faster. But I have decided to leave it as is and add the necessary cooling plenums to get the engine cooled properly. I can see no evidence that it ever had anything but a wide open cooling system, but I could be wrong. There aren't any rub marks inside the cowling from the rubber on the top side of the plenum.
It's truly a work of art given the fact it was never built from plans. All of the fairings (except wheel pants), cowl, etc, are hand formed from aluminum.
Russ Riter was an amazing man by all accounts having flown behind OX5's before the war and having some 15,000 hours after serving as a civilian WW2 pilot trainer. He built 15 planes (only one of his own design), a sports car from scratch in the 1950's (all aluminum hand formed), held every aviation cert possible, trained commercial pilots how to fly the new technology (glide slopes), etc, etc, ,etc.
Russ Riter built N1017Z in 18 months from scratch, with no plans from 1959-1961. The workmanship is very good. His son was 10 at the time (now 70) and told me his dad Russ never let him speak in the shop while he helped his dad build. He could only observe and listen. Being little, at that age, was good reason for his dad Russ to have him lay in the fuse and buck rivets! He said they practiced quite a while before he was allowed to buck on the airframe. The airplane was talked about in several magazines and EAA publications back in the 60's.
A fun fact of interest here in this forum is that there is even talk that Van spent numerous hours on at least one occasion one evening taking lots of notes and measurements from it back in the late 60's. When I first started researching it, I thought it was an RV3 / Mustang cross because of the wing, drooping ailerons, flush riveted skins (mostly), etc. But then I realized it was build 12 years before the RV3. The wing appears to be the same NAS23000 series the we know and love so well.
I have lots of photos, aerobatic testing including all entry speeds and approved maneuvers (including inverted spins, snap rolls, etc), wing loading tests, retract landing gear speeds and drop on testing (2G) (since removed). It features drooping ailerons, spring system that reduced stick effort when flaps were deployed, etc, etc, etc. It was said to be very light and harmonized on the controls. I could right a book about it I suppose. It is a historic plane and I'd like to do it justice so I have decided to leave it as built, but upgraded avionics, engine, etc. I have an O-320-G4 for it that is serial number L116-47. It was built in 1961 for the experimental market with no certification from Lycoming. It seems a perfect fit for doing this plane justice.
I have not flown it yet. It was last flow in the late 1980's or maybe 1990 when it was donated to the Sun N Fun museum in Lakeland, FL. Somewhere along the way it was purchased, engine sold and other small items removed, donated back the other mention museum here in Springfield, MO. Our EAA chapter had winter meetings at that museum and one day the caretaker asked if anyone was interested in buying a little airplane he had in the back. I said ya, he slowly walk me to the back of the museum, and it was love at first sight! A deal was made shortly after.
It has a very long history with the EAA and Sun N Fun. I have pages full of notes about it's history and where all it's lived. I'm finally moving forward with the project as I finally tracked down the old log book in California and got photos. I also received about 75 pages of information from the FAA including the airworthy certificate filed with the FAA. I still don't have the registration done (shame on me) but that's life I suppose. I now have everything needed as far as documentation to go through the process of getting it flyable again once it's back together and conditional is signed off. Although, progress has slowed again due to getting permanently laid off from from a wonderful Lycoming T53 engine and fuel control unit gig a few weeks ago.
It was said to cruise at 150 mph with a top speed of 170 with an 0-290, 400' takeoff, very docile, 6G+ 5.5G-, VNE 195mph. I'd have to look at the logs to remember all of what's there. It has removable (foldable with skin mod) wings, and counter balanced control surfaces on the tail. It also has a neat wire pull system with spring loaded pins that allows ejection of the canopy. It was flown mostly with the canopy off and I see no evidence of any seat cushion! Just a perfectly sized spot for a hindend mount parachute!
Forgive me for being long winded and not 1 single picture.
There's still passion and a fire burning inside the hearts of experimental aviators and builders and that nice to see! Keep it up.
Gosh where do I begin.
Once I move to writing I don't see the post so I'll just give you a little run down of it, but may not answer many questions you asked. When I can get to a printer to print out the above post, you'll get a much better reply.
My motivation WAS to make it look a little better and a little faster. But I have decided to leave it as is and add the necessary cooling plenums to get the engine cooled properly. I can see no evidence that it ever had anything but a wide open cooling system, but I could be wrong. There aren't any rub marks inside the cowling from the rubber on the top side of the plenum.
It's truly a work of art given the fact it was never built from plans. All of the fairings (except wheel pants), cowl, etc, are hand formed from aluminum.
Russ Riter was an amazing man by all accounts having flown behind OX5's before the war and having some 15,000 hours after serving as a civilian WW2 pilot trainer. He built 15 planes (only one of his own design), a sports car from scratch in the 1950's (all aluminum hand formed), held every aviation cert possible, trained commercial pilots how to fly the new technology (glide slopes), etc, etc, ,etc.
Russ Riter built N1017Z in 18 months from scratch, with no plans from 1959-1961. The workmanship is very good. His son was 10 at the time (now 70) and told me his dad Russ never let him speak in the shop while he helped his dad build. He could only observe and listen. Being little, at that age, was good reason for his dad Russ to have him lay in the fuse and buck rivets! He said they practiced quite a while before he was allowed to buck on the airframe. The airplane was talked about in several magazines and EAA publications back in the 60's.
A fun fact of interest here in this forum is that there is even talk that Van spent numerous hours on at least one occasion one evening taking lots of notes and measurements from it back in the late 60's. When I first started researching it, I thought it was an RV3 / Mustang cross because of the wing, drooping ailerons, flush riveted skins (mostly), etc. But then I realized it was build 12 years before the RV3. The wing appears to be the same NAS23000 series the we know and love so well.
I have lots of photos, aerobatic testing including all entry speeds and approved maneuvers (including inverted spins, snap rolls, etc), wing loading tests, retract landing gear speeds and drop on testing (2G) (since removed). It features drooping ailerons, spring system that reduced stick effort when flaps were deployed, etc, etc, etc. It was said to be very light and harmonized on the controls. I could right a book about it I suppose. It is a historic plane and I'd like to do it justice so I have decided to leave it as built, but upgraded avionics, engine, etc. I have an O-320-G4 for it that is serial number L116-47. It was built in 1961 for the experimental market with no certification from Lycoming. It seems a perfect fit for doing this plane justice.
I have not flown it yet. It was last flow in the late 1980's or maybe 1990 when it was donated to the Sun N Fun museum in Lakeland, FL. Somewhere along the way it was purchased, engine sold and other small items removed, donated back the other mention museum here in Springfield, MO. Our EAA chapter had winter meetings at that museum and one day the caretaker asked if anyone was interested in buying a little airplane he had in the back. I said ya, he slowly walk me to the back of the museum, and it was love at first sight! A deal was made shortly after.
It has a very long history with the EAA and Sun N Fun. I have pages full of notes about it's history and where all it's lived. I'm finally moving forward with the project as I finally tracked down the old log book in California and got photos. I also received about 75 pages of information from the FAA including the airworthy certificate filed with the FAA. I still don't have the registration done (shame on me) but that's life I suppose. I now have everything needed as far as documentation to go through the process of getting it flyable again once it's back together and conditional is signed off. Although, progress has slowed again due to getting permanently laid off from from a wonderful Lycoming T53 engine and fuel control unit gig a few weeks ago.
It was said to cruise at 150 mph with a top speed of 170 with an 0-290, 400' takeoff, very docile, 6G+ 5.5G-, VNE 195mph. I'd have to look at the logs to remember all of what's there. It has removable (foldable with skin mod) wings, and counter balanced control surfaces on the tail. It also has a neat wire pull system with spring loaded pins that allows ejection of the canopy. It was flown mostly with the canopy off and I see no evidence of any seat cushion! Just a perfectly sized spot for a hindend mount parachute!
Forgive me for being long winded and not 1 single picture.
There's still passion and a fire burning inside the hearts of experimental aviators and builders and that nice to see! Keep it up.
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gmcjetpilot
Well Known Member
Great post. Read every word. What a peice of American amateur built aircraft history. Thanks for maintaining this beautiful airplane.
