Graham wrote:
That’s my point. Most such projects do not ever deliver a product for sale and are quietly abandoned
Yes, but that doesn’t matter. What matters is that money is flowing into the hands of engineers and scientist and stuff gets developed. If only 5-10% succeeds in producing viable commercial products that is more than enough. The “failures” aren’t useless. Engineers/scientists simply move on to the next and take all the experience and knowledge with them. Lots of investors will surely lose lots of money, but a few will succeed. A very few will succeed big time. It’s like a gold rush. Most came back with nothing, having lost everything. A few became millionaires, and among the few were those that made spades, supplied food and shelter etc.
LeSving wrote:
Lots of investors will surely lose lots of money, but a few will succeed. A very few will succeed big time. It’s like a gold rush. Most came back with nothing, having lost everything. A few became millionaires, and among the few were those that made spades, supplied food and shelter etc.
I see the analogy, but it doesn’t quite hold.
A gold rush was mostly a matter of luck. Critically, the gold was definitely there – it was just that some found it and most didn’t. The viable electric aeroplane for commercial use above the 2-seat ultralight level is not necessarily definitely there.
To make it so will require battery mass vs capacity to advance by an order of magnitude, and I am not aware of anyone really having any idea of how to make that happen at the present time.
As far as I can tell, most of these electric aeroplane projects dedicate their efforts to using advanced aerodynamics, composite materials and other interesting design ideas to reduce, by a relatively small amount, the degree to which battery technology needs to advance to make it viable – e.g. we have come up with a ‘plane in which you only need to improve current battery mass/energy by 500% instead of the normal 600%. The underlying assumption or hope seems to be that during the period of the plane’s development, battery technology will advance as required and thus it will all work out when we are finished. The projects end when the airframe/powerplant/systems development is complete and the only thing left to add is the batteries, which of course do not exist in the mass/capacity required. So you’re left with a great prototype aircraft which may even have flown, but can only fly for some commercially-useless amount of time.
I agree with you that it is fundamentally good for science and technology that this money keeps flowing. You will never make it if you don’t try! All I’m saying is that, like in my game (pharmaceuticals) the ‘make a really good living whilst slowly failing over a long period of time’ model of consuming investor cash is well-established.
If some big name pours say 10M/year into a “green” project like this, they will get much more media coverage, and of high quality, than if they just spent the 10M on brand advertising like everybody else has always done.
Also, media hacks are primed to cover this topic above everything else. There is simply NO downside. It is absolutely fabulous and wonderful and totally fashionable. The more floods and fires and natural catastrophes there are, all due to man-made climate change of course (that is proven, no question) the more receptive the media is to anything in this department. There is nothing which is not to like, as the saying goes. It is win win and win for everybody.
Something might come out of it one day, but it will need
Of course there are no reserves in the ranges quoted. The sort of reserves which we expect in aviation (and we expect them for very good reasons) are much longer than the entire battery endurance of these projects 
Graham wrote:
All I’m saying is that, like in my game (pharmaceuticals) the ‘make a really good living whilst slowly failing over a long period of time’ model of consuming investor cash is well-established.
Very well established, government cash too. Some good will come of it, limited applications and technology spin-offs.
My plan is to retire in about 5 years, with time and money to fuel my O-320 regularly. Or maybe an O-540
LeSving wrote:
The Slovenian air force will use the electric Velis from Pipistrel as a trainer. The Danish air force is purchasing two for evaluation.
EHTE, where my maintenance shop is located, has a couple of these Velis airplanes used for circuit training. I was once behind one doing my run-up, and I noticed the prop was still during the pre-takeoff checks, so clearly they’re aggressively managing power consumption. While obviously a long way from most practical uses, there’s obviously a market for training and possibly short sightseeing flights in the short term.
dutch_flyer wrote:
I noticed the prop was still during the pre-takeoff checks, so clearly they’re aggressively managing power consumption. While obviously a long way from most practical uses, there’s obviously a market for training and possibly short sightseeing flights in the short term.
I don’t doubt it needs aggressive power management. The claimed endurance is 50 minutes plus a 30 minute reserve, but:
- that will be based on full power for takeoff, then climb to some (low) altitude and best endurance power setting thereafter
- it will not achieve the claimed endurance below ISA temperatures
- who really wants to plan to land with only 30 minutes endurance remaining?
Why would stopping an electric motor when power output is not needed qualify as “aggressive”?
To put it otherwise why would I want the prop running during takeoff checks if I don’t need it?
Limiting speed and motor power on the Taycan to increase range, that I would call “power management”. Stopping the traction motors at a red light… not sure.
A very fair point.
Does anyone know if pulling the power to zero/idle actually stops the prop, or do you have to ‘turn it off’ more than that to stop the prop?
Graham wrote:
best endurance power setting thereafter
And for the joke to relate to a very common topic, is that Lean of Peak :-)
Does anyone know if pulling the power to zero/idle actually stops the prop, or do you have to ‘turn it off’ more than that to stop the prop?
I think the Velis has fixed pitch? Then I would think zero throttle is zero torque, which translates to always running propeller when positive IAS. It could also be a control for the rpm exclusively. Or maybe a mix, who knows?
