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Pressurized Cockpit?

milt1492

Member
I'm very new to the aircraft building game...so new that I haven't yet decided what kit I want to build. My wife has given me permission, and is very excited for the day that it finally gets finished. I've been looking at Van's kits since a deployment to the middle east in 2004.

From my Air Force days, I recall the love of flying T-34Cs and all of the fun I had in that great little airplane. The only thing I wish it would have had was a pressurized cockpit.

I guess I have a few questions...

1) Has anyone else even approached the idea of pressurizing the cockpit of their RV?

2) If so, what was required to accomplish that feat?

3) If you decided against it, what was the reasoning behind your decision?

I throw this out there because it will always be nicer to fly higher to get over the weather, or get to where you're going faster Besides, wearing an oxygen mask can get pretty uncomfortable. I can remember that on a few occasions, especially around Pensacola in the late afternoon, that 10,000MSL just wasn't high enough.
 
Welcome to VAF!!!!

Hey Milt, welcome to the good ship VAF.

Good to have you aboard.

Pressurization is pretty much out of the question here, it is all we can do to control the cold air leaking in.

Lancair has a pressurized model--------way more expensive and complicated than the same plane without pressure.

The forces on the windows alone are enough to scare me-------assuming all the rest of the myriad of issues got solved.

Most of us use a cannula when we need O2, but if you really want to go high, use a pressure mask???
 
Pressurization

From a comfort standpoint, it is an appealing idea. From the practical side, it is nearly impossible. The physics go something like this; with a modest 5 psi cabin pressure the stress on the airframe will be 720 pounds per square foot. Put another way, the canopy on my '8' would have to withstand nearly 10000 pounds of force. Looking at the structure, I have a hunch it isn't quite up to that. :rolleyes: Anything is possible but in this case it would require starting a new design from scratch.

John Clark ATP, CFI
FAAST Team Member
RV8 N18U "Sunshine"
KSBA
 
Many Hurdles

Weight would be your biggest issue. There are some great engineers on this forum, and I am sure that you will get some good thoughts from them. Here are but a few of the hurdles you would have to jump:

1. Increasing the structure of the cabin area to withstand the presurization.
2. Increasing the structural capability of the canopy and attach points. (IMHO, a tip-up would be the way to go)
3. Fabricating a system to control the cabin air both in an out.
4. The engine would need a turbo-charger to provide engine power at altitude, and bleed air for the cabin.

One thing that I have learned from being in this group is that the word "impossible" does not exist. If you were truly dedicated to doing something like this, with the proper engineering, time, and most importantly
.....MONEY it could probably be done.
I agree with Mike in that just give in to "sucking the hose" while you are at altitude is the way to go. My pipe dream is to put a turbo-normalizing system on my RV, so that I could maintain power during high altitude operations.
 
this is one area that composite planes excel, it is easy to seal or already have a continuous cabin. much different from an aluminum plane, where every seam, while strong and/ structural, is a leak point along the whole length.

the lancair evolution is a very light plane for what it is, and getting it to pressurize to the limit they wanted (8? ) meant it had to hold 150% (12) for a very short time. they'd have a leak in this area, reinforce it, then the next weakest spot would spring a leak, and so on. I think it was tested 3-4 times before it held. All part of normal prototyping for a new design, but i wouldn't want to do it for an aluminum plane.

sometimes when a plane is pressure tested it will in a sense "blow" as in have a major area failure. not very fun, and it can ruin your test vessel. think projectiles also. this is an area i don't think is really suited to home experimentation.
 
pressure vessel

I have quite a few hours at 12,500 to 17,500 in my RV. I'm comfortable and warm. The only thing I had to do was put in an oxygen tank. I could go higher but I'm VFR. Steve
 
Think about pressure testing fuel tanks!

Before I figured out how to use a balloon to prevent overpressurizing my fuel tank during the leak test, I saw first-hand the results of only 1 or 2 psi on a thin wall aluminum structure. Not good!

Nope! If you want a pressurized airplane, build the Lancair. :D
 
Real Men Pressure Breath!! ;)

I agree with those who say that redesigning the RV to hold pressure would essentially create an entirely new airplane - and, unfortunately, one that would be too heavy to perform like an RV. Interesting idea though, and it never hurts to ask the question....

Paul
 
Even most of the pressurized Lancair builders that I've dealt with say that if they had it to do over again, they wouldn't go pressurized. It's a real hassle. Remember, everything that goes into the cockpit, brake lines, control cables, pushrods, everything must be sealed to the same standards as the cabin walls and doors.
 
Thanks for the help

I just wanted to thank everyone for the knowledge that was imparted to me. I wish it was like this on another forum that I'm a member of.

Anyway, I did some reading up on supplemental oxygen systems and have decided that using oxygen is the way to go. Hey, I've still got my AF flight helmet and mask!
 
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