A pilot on the Vans RV forum told how he got his RV8 to 28,000 ft. Though impressive, it seems like a risky flight. What consequences, if any, with a failure of his 02 system?

other than being dead I suppose it would be ok

I hope that he was using a pressure breathing regulator system for the flight.

@ 28k MSL the time of useful conciousness is 2.5 to 3 minutes. If you smoke or have diminished lung functions ... even less.

To get from 28k' to 10k' will require a descent of 7,200 FPM. I wonder if he bothered to
practice this life-critical maneuver?

Related; http://www.avweb.com/news/pelican/Pelic ... 156-1.html

Does it really? As long as a descent is initiated immediately, even descending at "only" 3,000 FPM will start the trend towards more oxygen and thus more time of useful consciousness. In other words, things get better gradually from the moment the descent is started.

So I assume the key is to initiate the descent without delay, and that that is more important than to descend at a ridiculous rate. No?

- Martin

Every 1,000 feet you descend gives you another minute or so more useful consciousness. Glider pilots in the Sierra wave regularly fly above that and I can't remember the last time someone died in a glider due to an oxygen system failure. Someone flying along in a pressurized plane may be a little lax in monitoring their pressure/oxygen system, but I guarantee you that most people flying at those altitudes depending on an oxygen system are keeping a very close eye on things.

I flown at 25,000' in my plane and I had a second O2 bottle/system next to me ready to use if I needed it.

Vince

25,000 is the current limit for pressurized aircraft without redundant systems. 28 isn't far off that. It's more dangerous than chess club, but isn't reckless.

https://www.vansaircraft.com/pdf/hp_limts.pdf
Would worry me more.

It's easy to sit at a desk and say that. A run through the altitude chamber should convince anyone that the key isn't getting down, it's processing the information to decide that there is a problem and deciding to start down

It's easy to sit at a desk and say that. A run through the altitude chamber should convince anyone that the key isn't getting down, it's processing the information to decide that there is a problem and deciding to start down

NA engine?

maybe. Max mp about 10" at that altitude or about 30% power. A 210hp engine would make 60-65hp. Probably adequate for level flight, especially if the plane was light for the attempt.

I had my NA Comanche 260B to FL210 before, on a very long cross country (SJC to ICT, ride those winds).

Pretty meager power, about 14" MAP.

But it flew, and not that light, either.

A much lighter RV8 with the same engine seems like it could do it, though not loaded for range.

Mike C.

Technically, wouldn't the pilot just need to set a decent down to 10,000 feet. No matter the fpm decent - he would most probably regain consciousness once the plane continued down and leveled off at 10k feet. Cirrus does this in the new models if you don't touch anything for awhile..