How High?

[Monkey]

Cool!!! I was wondering about the canopy shrinkage at the temp? Is it riveted or sickaflexed ? Any cracks around rivets or separation from the bonding?
They know about the shrinkage...don't they?

[TS Flightlines]

Monkey has a point. At those altitudes, what kinds of structural things are happening? Canopy breakage, possible freezing of flight controls?
Something I didnt think of, but I'm sure others have. I dont plan on flying that high, but its also good to know that it has been done.
I'll talk to my mentor, Lee Logan about it.
Tom

[nigelspeedy]

Paul330,

You make some very good points and they are well worth brining up.

I thought quite a lot about this before I did it, it wasn't just a spur of the moment activity. Risk management is about making things as safe as reasonably practicable, ensuring the risk is worth the reward, and within your personal tolerance level. I only planned on doing this once which limited the exposure to the hazards. I also accept that a lot of people will not want to do this.

You can pick your day and hence the weather, winds at altitude and turbulence. On my flight it was glassy smooth above 8k but as you allude to mountain wave or jet stream could easily create turbulence that could exceed the performance capability and structural limits of an RV.

You need to be careful with your IAS on descent if you don't want to exceed the Vans recommended TAS limit. Easy if you have an EFIS that displays it real time, but a prepared IAS v Alt VNE limit chart would be wise if you don't have that luxury.

I don't think there is any great risk to a negative groundspeed if your indicated airspeed is positive, but I am a helicopter guy by trade so I think backwards is a normal mode of flight. Could certainly be inconvenient if you were constrained by airspace though.

So far the canopy has help up. It was mostly riveted on and Sika flex used in spots to fill gaps.

You are right about the risk of DCI or the bends, in some places they won't let you fly above 18k unpressurised without pre-breathing 100% for sometime. I have had the luxury of doing several chamber runs over the years and am familiar with my personal hypoxia symptoms and they are quite consistent. The FAA runs courses that you can do for free and if you haven't had the chance to experience hypoxia I heartily recommend you get some training. I made sure my O2 system was serviced and took a spare controller. I wore a pulse oxy meter the whole time and checked it regularly. I also wore a parachute.

Still. there is no denying you are left with some failure modes that have likely catastrophic consequences and some probability.

Cheers
Nige

[pvalovich]

For all you naysayers:
Speedi is a test pilot instructor at NTPS, is very familiar with the airspace and terrain, REALLY understands what his airplane is telling him, is very familiar with high altitude physiology, understands how to work well within R-2508 and with the procedures used by Joshua Approach controllers, and like all of us who regularly fly over the Southern Sierra, probably has well thought out Plans B, C, ....when things start to go south.

Attaboy Speedi - keep expanding the envelope and our knowledge of it. Although after spending 10+ hours in temps in the low twenties on a recent flight to PA from IYK, I have no desire to fly in air any colder!

[N941WR]

Nigel,

Do you want to try that with my O-360 powered -9?

With the Ronz airfoil and longer wing, I'll bet you could go a good bit higher.

Couple that with the EICommander to keep track of the ignition, you should be good to go.

[rvisnext]

Nigel, your high altitude run is very cool in my book. thanks for the report. I have seen your dyno charts, I was wondering what your RV-8 does wide open?

[boom3]

Very cool Nigel!

In May of 2008, John Brick flew his RV-4 with an IO-360B1B to FL280 (28,250' MSL). I remember him talking about how cold it was, if I recall correctly he said it was -60F.

[airguy]

Originally Posted by N941WR

Nigel,

Do you want to try that with my O-360 powered -9?

With the Ronz airfoil and longer wing, I'll bet you could go a good bit higher.

Couple that with the EICommander to keep track of the ignition, you should be good to go.

That just what I was thinking - with my IO-360, EI and CS prop this should be achievable. Proper attention to risk management is a must, however. Physiological factors are a prime attention-getter.

[dwrichey]

I too think this was a very interesting and cool thing to do.

I'm wondering why the airspeed was so low. Was it because all the thrust is being used to keep the aircraft at altitude, kind of like a helicopter?

Were you right on the verge of a stall?

Just curious.

[rvisnext]

Originally Posted by dwrichey

I too think this was a very interesting and cool thing to do.

I'm wondering why the airspeed was so low. Was it because all the thrust is being used to keep the aircraft at altitude, kind of like a helicopter?

Were you right on the verge of a stall?

Just curious.

I think you are right, look at his AOA/lift reserve on the EFIS display...No green at all

I'm also wondering if overspeed of the engine is possible? because the C.S. prop has to run out of coarse pitch at some point(not a lot of air molecules to push against). Or maybe it doesnt matter because the engine is limited to approx 33% power. Any engine parameter screen photos Nigel?