Tall Man Mod

[Dayton Murdock]

Hi All
My son wants to fly my -4, But he is 6'4" and can't get in the front seat, has any one done the tall man mod to there -4? and what does it entail?

[tgibbs]

I bought my 4 from a guy that was that tall, he just had different shorter and narrower cushions that he used. Nothing else is different.

[FinnFlyer]

Possibly recline the seat back a bit. Rudder pedals as far forward as possible.

Then the tough one: raise the canopy (and/or a custom canopy with a bigger bubble).

Finn

[DeeCee 57]

and the really tough one, recall reading about someone who repositioned the roll bar towards the rear by 1-2”...

[penguin]

The construction manual talks about arranging the cockpit for additional leg room, but it is something done at build. If thin cushions wont work it is probably major surgery? Can the rudder pedal fish plates be lengthened without the pedals hitting the firewall?

[fixnflyguy]

Dayton,
The -4 as you know well, has very limited strechability without interfering. I spent alot of time squeezing all I could out of mine while building, and while I don't have a "tall man" mod, take these considerations Adjust pedal cable linkages to make travel go all the way to firewall. The seat pads reduced to bare minimums, and If you move the seat back AFT, the rear stick may hit and need adjusted AFT as well...which jams the crotch of a PAX. The upper edge of the seat back can be reconfigured to mount on AFT side of rollbar crossmember, but it has to be robust to prevent a high G load separation. I moved my rollbar AFT 1" during build, and also changed the stiffeners below it to stay centered. All the rollbar and seat changes will make the canopy crossmember susceptible to hitting the rollbar, so that has to be done carefully. The biggest factor for a tall pilot is the leg length and knee clearance. Ultimately, a new panel with knee clearancing may be the final solution..I have nothing hanging down from my panel...It can be done, just a bit here, and a bit there, and a bit more somewhere else.

[Scott Hersha]

I’ve given two RV4’s a “tall man” mod, my first one that I didn’t build, and the one I have now, that I also didn’t build. I moved the roll bar/seat back support aft 2.75”, and the seat bottom piano hinge support aft 1.75”. This gives me a little more tilt, which is comfortable for me. I am 6’2” and have a 32” inseam, so I’m a little long waisted. Doing this requires some structural changes, and they are briefly outlined in the build plans that came with the kit. The sidewall support has to be modified to allow a load path for the moved roll bar. The canopy cross brace also must be moved aft by the same amount as the roll bar - 2.75” in my case. For me, this is a very comfortable cockpit now and I have more room between me and the instrument panel. Comfort for the back seater wasn’t good before the mod and less so now. My wife doesn’t like the back seat of any tandem airplane, so for me, it doesn’t matter. My grandkids love it. The rear stick did interfere with the front seatback in the full nose down position, so I just removed the stick - at first. When I did my first condition inspection, I discovered that the builder had built the elevator control stop 6* too far nose down. Nose up was fine. I rebuilt the control stop and now the rear stick doesn’t interfere, although it’s close at 1/2”. The other thing that drove my decision to do this had to do with weight and balance. My empty weight is 981#. With me in the front, 15 pounds of tool bag, etc in the bag bin, and almost full fuel (30gal), I have enough useful load for my 125# wife and nothing else to stay within my 1500# designed GW. All of this is fine with me. I seldom take anyone flying with me, and when I do, it’s a short local flight, so no need for a lot of fuel. CG has to be minded any time there is a back seater or baggage. This airplane was never designed to be a cross country airplane for two people and luggage. That airplane is the RV8.

[Rick RV-4]

Don't forget options that may be out there for a taller canopy. I went with the canopy from Todd's Canopies (not sure if they are still around) and the canopy had a LOT more vertical room than the standard Van's canopy. I'm not very tall (5-10") so I added a few inches to my seat cushion (beacuse I could), so I sit up "taller" than I do in a lot of RV-4s. Visibility is fantastic and I would do it again.

[Lufthans]

I'm 6'4" as well. I've since sold my share in the -4, but my solution was to simply take the back cushion out. Surprisingly comfortable still...

[riobison]

A set of thin soled Sparco Racing Shoes or similar and you will gain another 1/2"+

Made a big difference for me. As well they will prevent your shoes from catching on the nuts and cotter pins on the rudder pedals.