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Cockpit Size and mods

CAVU Mark

Well Known Member
I may have a chance to purchase a RV-3 at a good price. Problem is I am 6'3" and the 2 RV-3s I have tried on for size are small. Are there any tall RV-3 drivers out there and if so what type of mods did you perform. And I know inseam changes things.

My first thoughts include kick outs in the firewall to allow for further forward rudder placement, knee notches in a new panel, and I don't believe the seat moves aft at all. Any one tall out there?

Thanks.
 
rv-3 fitment

Mark
At 6'2" the pedals were way too close. I moved the hinge point of the rudder pedals back (holes already there) and lengthened the connection between the pedals and the rudder cables (fabbed out of light sheet metal). That is all I needed to do.
As you recognize, the firewall will interfere with travel at some point. It sounds like what you need to figure out is whether there will be interference when the pedals are put through the possible rudder and brake motions. IIRC, the key is full rudder and full brake.

It does make a difference on the torso versus leg contribution to height. I suppose if moving the pedals isn't enough, then maybe a custom back pad could be tried, before working on the firewall.

Comfort is relative. I find the cockpit very comfortable but it might be that sitting for hours in a kayak (decked canoe for the Brits) has anchored my expectations low.

best of luck
 
Knees and cushions

The 3 I tried at my EAA chapter did have both cushions removed and my knees knocked the panel. Better have good upper arm strength to get out. That is why I mentioned reducing the panel around the knee area.
 
RV3

If you don't mind doing some modifications to the rudder pedals you should fit. I'm at 6'3" and I built a 3B. What I did was buy the parts for an RV6 overhead rudder pedal assembly from Vans. I cut them in half and installed angles for them to attach just like the 6. I mounted them high enough so you can also put your feet under the pedals in cruise flight and stretch out to the firewall. This was about ten years ago but I should be able to dig up a photo if interested.
 
Mods look good

Excellent suggestions. Thanks. Combined full rudder and braking would need to be watched carefully, and I sure don't want heel brakes. :D
 
RV-3 changes

When I purchased my 3 I made a couple changes. I took 1.5 in out of the seat back cushion so my shoulders just touch the Fiberglass seat back when compressed. With my torso length I never changed the seat bottom, I could take an inch or two out but haven't, but in severe turbulence I do bump my head on the canopy. I am 6 ft with 32 in inseam, but I like leg room. Then I moved the rudder pedals to the front most position. I then fabbed new rudder cable mounting tabs to move pedals forward a bit. When I'm on longer flights I wear narrow shoes, then I tuck my feet under the pedals and can stretch my feet to touch the firewall. My panel is high enough that I clear my knees by about 3/4 in. Not as much room as my 6, but comfy enough.
 
Since this was one of the first threads that came up in Google dealing with the RV-3 cockpit size, it seemed appropriate to annotate some dimensions from the RV-3 preview plans as regards the cockpit sizing. As I'm 6'5" tall, but only 180Lbs and suffering empty nest syndrome now my -9 is flying, I'm investigating the RV-3 while attempting to convince the KRviatrix another RV build wont cause AIDS....

Now, since these dimensions are sourced from the preview plans, there may be some error vs actual measurements from an in-service RV-3. They're worth what you paid for them! :p

So, on to the dimensions.

  • From the F305 bulkhead located immediately behind the seatback to the firewall is 49.0 inches at the lower longeron.
However, the plans show the seat back is hinged to the seat ribs approximately 3.05" forward of the F305 bulkhead, meaning you have a total of 46ish" from bumcrack to firewall.
  • From the F305 bulkhead to the firewall is 53" along the top longeron.
  • The seatback is 18" wide and 24.375" tall.
  • The cockpit width is 24" from skin-skin at both the knees and backside.
  • There are approximately 20" from the seatpan to the top longeron and another 18" from the top longeron to the canopy roughly where your head would be for a total seat height of approximately 38". This is slightly variable depending on the cutout of the seat ribs & consequent butt position.

So all up, when compared to the -9, the RV-3 cockpit is between 1" & 5" shorter (dependant on rudder pos'n in the -9, I used Van's published cockpit sizes for the -9 dimensions) and has roughly 3" less headroom.
 
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Well I bought the plane

I moved the rudder pedals as far forward as possible. I don't see mounting, floor vs. hanging as much difference since the travel needs to be the same regardless of where they are mounted. I removed most of the seat cushion and I still haven't flown the plane!

A recent test flight revealed a fuel leak, issues with the radio which previously worked and some elevator issues. So, back to the shop to learn all about Proseal. :(

Mark

P.S. a bargain is not always a bargain.... but we all know that, don't we.
 
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Greetings,

It's good to see a recent discussion about cockpit dimensions, but there hasn't been much discussion about headroom. I'm 6'-1" but it's all neck, and my seated height is 39". Legroom is never a problem, but headroom is.

Years ago, I finished an RV-3 project that initially had a sliding canopy fitted, and as I recall, I had no extra headroom. That was a very early kit, and I have to believe canopy manufacture has changed a bit since then. I also know there's some variability in how high it's mounted when installed, so I'm not sure I can go by the way that one fit. I ended up having a custom canopy made by Todd's Canopies (RIP) and changed it to a tip-over.

Now I'm in the market for an RV-3 or -4, and I'm wondering if anyone would be so kind as to measure your maximum headroom. The best way to do it is to sit in the plane with no bottom cushion, and with your head where it would be in level flight. You can estimate the clearance (2 fingers, 3 fingers, etc), then add that to your seated height.

Of course if there are any RV-3s close to East TN, I'll be happy to measure them personally :D

Thanks,
Rusty
 
Hi Rusty,

Good to see you 'surface' again. Your -3 was here at Slobovia last month for our rotary roundup; Finn has it now, based at Shady Bend.

I'll try to measure my -4 for you, but you'll almost certainly fit in a -4. BTW, I know how fast you can build. Come on down & help motivate me to finish the -7, & I might make you a smokin' deal on the -4. :)

Are you anywhere near Chattanooga? We drive through there several times a year to see grand daughters in NC.

Charlie
Slobovia Outernational
 
Hi Charlie,

I've emailed Finn a couple times, so I knew he had it. He missed his chance to sell it back to me now I guess, since I've got a deal made to buy a -3B (assuming I fit).

I can't help you with building motivation I'm afraid. I can't seem to motivate myself anymore :p Years ago, I started a -3B project that was going to be Lycoming powered, but got unmotivated and sold it to Paul Dye. He appears to have done a better job finishing it than I would have :)

Cheers,
Rusty
 
Just measured mine. I measured from the seat pan (no cushion) to the top of the closed canopy. Measuring from just in front of the seat back: seat pan to slightly forward of vertical is ~39 1/2". Absolute best case (seat back in aft-most position, measuring from hinge point up, following the roll bar angle, was 41 1/2". Of course, you can't get your head that far back. And as you mentioned, build technique will have major influence on the final measurement. Mine has barely enough clearance between the roll bar top to the canopy to fit a very thin GPS puck; probably less than an inch.

You can make the -4 a lot more comfortable by moving the top of the seat back. Instead of it resting on the rollbar cross-brace, it can go behind it and be held with adel style clamps. Changes back angle just enough to make a big difference in comfort. And if you've got short legs, you could move the hinge point forward to pick up a bit of vertical, due to the angle.

Charlie
 
Thanks for the measurements Charlie. 39-1/2" would give me a half inch to spare. Best I can hope for with the RV-3B is that they changed the canopy, or the builder mounted it as high as possible. There's only one way to find out.

Rusty
 
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