eurogaguest1980 wrote:
because I like to fly over the alps at about 13k or higher, sucking on my oxygen concentrator.
I’d never do that. Ok, if I’d poke fun at anybody, that would be ’cause I care for them. Having respect for terrain sure is a healthy attitude 
SteakAndAle wrote:
A common question was “what is your aircraft?”. Well, at the time it was an Arrow II – but now it’s an RV9.
Another common question is “do you want to fly in the Alps or over the Alps?”
Dan’s always poking fun at me because I like to fly over the alps at about 13k or higher, sucking on my oxygen concentrator. 
I like it since I get the beautiful views, smoother air, extra time to find a place to land in case of engine problems, and a chance to do things like mag checks and GAMI leaning tests at altitude.
Flying to Aosta from the north is quite easy – once you get towards the end of Lac Leman, climb from about 7500 to about 9500, follow the valley, and in about 15 minutes you’ll be descending again into Aosta. If it’s bumpy at the end of the lake, turn around and land in Lausanne and wait for smoother air. Or climb to about 14.5 where it will be smoother, but get ready for bumps when descending into the Aosta valley. Geneva Info will almost always approve whatever altitude you want once you get to the end of the lake, heading towards Bex.
I don’t mind a bit of turbulence, since I know my wings won’t fall off, but my passengers really don’t care for it, for some reason. Perhaps it’s because they know I built the airplane in my garage.
Aye, we’ve found that she gets pretty close to the Vans max/min numbers – but would be good to have some rough numbers in my head for performance above flatlander altitudes
SteakAndAle wrote:
The good thing is that with an O-320 & a C/S prop it has fantastic climb performance – but the downside is that, as a permit aircraft, it has no performance charts. So a good experiment would be try a prolonged climb to get an idea of performance at altitude, as a few posters suggested. But before that, we’ll need to replace our unreliable OAT sensor to get good DA figures…
It never hurts to be prepared and careful but I suspect that with an RV-9 you should have no major issues. That wing is optimized for high altitude. Vans data is typically pretty accurate and with a 160 HP O-320 the published service ceiling is 19,000 ft, with sea level climb of 2,000 fpm. Do ensure your high altitude leaning technique is OK.
An RV-7A owning friend did once have a ‘moment’ with his plane at Mammoth California airport, taking off at something like 9,000 ft DA. I haven’t flown there but apparently the winds can make for odd downdrafts and he was barely able to climb despite the healthy aircraft performance.
Hey, I am reappearing in this old thread that I started over a year later I didn’t realise how large it had gotten!
Sorry for the absence – the reason for disappearing was that around the time that it got to page 2, one of my friends & I got fed up with the aircraft group we were part of and decided to strike out on our own. As I’m sure you all know, buying an aircraft is a deep rabbit hole to fall down and it took up most of my thoughts & time for the next few months! In Feb 2022 we found ourselves with an RV9, and proceeded to fly the trousers off it for the rest of the year. It was a great year of flying for all of us, but an “Alps trip” did not feature for me – although one of the group has taken her that way.
Now it’s 2023 and I’m thinking about what trips I’d like to do this year, and my thoughts have turned back to the Alps – in particular, I’d still like to do Brenner → Bolzano for some climbing this summer. Aosta is also interesting as Peter seems to like it so much
I have another 7 pages of thread to catch up on, but just to say thanks for everyone’s input. I’ve also acquired a copy of the Shirt Pocket Mountain Flying Guide (a cut-down version of the Bible), and the New Zealand CAA’s mountain flying guide which seems a good, concise guide.
A common question was “what is your aircraft?”. Well, at the time it was an Arrow II – but now it’s an RV9. The good thing is that with an O-320 & a C/S prop it has fantastic climb performance – but the downside is that, as a permit aircraft, it has no performance charts. So a good experiment would be try a prolonged climb to get an idea of performance at altitude, as a few posters suggested. But before that, we’ll need to replace our unreliable OAT sensor to get good DA figures…
The windshear case/ downdraft is the only case where airliners have to pull until stick shaker. Of course if you hit a tailwind after downdraft, you will loose again altitude to regain airspeed, but in this case you need to maxperform the airplane in a spatial manner in any case because anyway it will push you down one way or another.
Here is a nice video about that, not completely unrelated with mountain flying, with a microburst crash study at the end.
This video is really great, so much to learn.
You’ve written that a lot clearer than my Alpenmanual did!
UdoR wrote:
I know that in that very picture the grooves and ridges are not so impressive, but I think it’s good enough to get the point.
Air does NOT flow vertically into the ground, period. What it does however is to change vertical velocity into horizontal velocity. You are throttling along. Then you hit a downdraft. Instead of going with the flow and maintaining airspeed, you pull the stick to maintain alt. This reduces speed, and in a moderate to strong downdraft, a typical GA aircraft will not be able to maintain alt. You are at the stall limit, losing alt. Then when getting closer to the ground, the downdraft will eventually turn horizontal. If you are unlucky, this horizontal component will smack you in the tail. Let’s say 20 knots. If you are already at the stall limit, let’s say 50 knots, then suddenly losing 20 knots will make you fall to the ground like a leaf.
Downdraft will never smack you to the ground. What will smack you to the ground is if you don’t maintain airspeed. The sudden horizontal wind shear component close to the ground will make the airplane stall. There is only one way to cope with this situation, and this is to maintain airspeed, which cannot be done by pulling the stick trying to maintain alt. You can also fly higher of course, which is always better.
to keep the whole Flarm talk Mountain Flying related, I feel that Flarm might have saved me a couple of times. One rarely expect opposite traffic at FL120 in the form of an almost invisible glider pointing at one’s nose…
Nice also to see that more and more hang gliders are Flarm equipped. They can hundreds of them hunting thermals on any given nice summer day, Flarm gives me some piece of mind…
Thanks! That panel looks beautifully dond!
