Altitude plays also a role in Fatigue, especially if you don’t fly very regularly. If so, mental state is always in a very vigilent status that pumps up energy and oxygen from what is available, and general fatigue is a consequence. If you can possibly grab an oxygen dispenser, it’s worth a try even at 7000.
I’ve been flying 7 hours yesterday as SIC in a jet on 3 legs, haven’t done it since 3 monthes, and indeed mental load was high as for most of this time. I was depleted on the evening.
@kwlf – my first thought is “sea level to 7+k”… and before flying you spent alot of time working/concentrating. No surprise to me that you felt tired/fatigued at the end of the day.
I was working for a month in Wyoming and found a C172 to fly within days of arrival. The chap said “come back at the end of your trip and we’ll fly”. For the next week or two I was constantly feeling unusually unfit and knackered. After a week of this I brought it up with colleagues who imediately laughed and said “hey you are at over 7000ft here…”. I have a nice in-cockpit shot of a final approach with 8k on the altimeter… 
Regards, SD..
I’ve always found flying tiring afterwards, even though (as someone has said) on the face of it you’re just sitting there watching the view. It takes much less concentration than driving, where even a second of inattention can easily kill you.
I’ve never really understood it.
To me, the stretching part of my twice weekly sports is a major factor. Before I started out a few years ago, I couldn’t touch my toes when standing legs straight. That and the excessive weight made me finally do something about it.
@Dan, I’ve had a 1980 900SS since the early 90s, mine also bought from a friend. I feel your pain It’s been a long time since I rode that particular bike for a full day, and with good reason!
I’ve been exercising more recently and find it helps, As I make my way slowly but surely towards my 60s I refuse to stop doing the things I enjoy, even if it hurts a little now and again. Flying is interesting to me in that contrary to popular perception it is less physically demanding than many other activities and as long as you don’t fail your medical you can keep doing it without issue. Aircraft maintenance however can be a bit challenging
One of my best friends in aviation is 78 and flies his RV-8 often. He also works on it. Walking several miles every day for exercise must help him.
Altitude definitely has a noticeable effect. A few days at 7000 ft in Mexico City not long ago showed me that.
Silvaire wrote:
I’ve had a 1980 900SS since the early 90s
The 916 in my case, lovely bike, but yes painful in particular if you’re on the larger side…
The 916 is a work of art in the way it’s made, worth having for that a alone. I have a 996 too…. with very low miles. It’s more effort to ride than the old SS (really) 
But I have other bikes that are good for all day riding. My V85TT is so effortless to ride its almost boring, but it does the job.
Flying is I think more of a maintaining concentration effort. Lots of things going on at once, watching all, keeping all within reasonable control. It’s the effort in the hangar that’a physical. I’ll have a helper today, it appears, no bad thing.
Dan wrote:
As for VW aero engines, they usually are a PIA to get hand started, true. Local group owns a homebuilt Kolibri, and last time I saw them they spent the better part of half an hour to bring the beast to life.
Does the Kolibri have a magneto impulse?
Starting a VW aero engine is, in my experience, absolutely dependent on priming. Me, full throttle, full choke I suck in 10 to 12 blades (depending on how chilly the weather is). Still full throttle, close (open?) choke, reverse a couple of blades, throttle set for start then…walk away! Go have a pre flight pee or whatever but leave it alone for a minute or so, set the blade against compression, switches on and it’ll usually run within a couple of blades.
Caveat, my mag does have an impulse.
Tubs I used to fly had WW1600cc with Leburg Dual Ignition Kit (electronic ignition not an impulse mag)
On dump winters one can get a***d hand proping (especially when alone on trip) the whole “gym practice & arm pain problem” was solved by buying 45£ portable heater, previously, it was solved by walking away to clubhouse and wait for the sun to warm things up
Pointing aircraft into wind or putting nose into exhaust seems helps, I can’t explain it but apparently it does
Not sure what you mean by nose into exhaust? I’m going to start a separate thread on VW starting as it’s clearly worthy of one.
