Thank you it is good to get information from someone who has flown it. Please note the FAA 30 minute reserve is ‘normal cruise’ not 30 minutes at minimum cruise power/descent power. I think that is why the endurance that the flight test engineers at Florida Tech are seeing is less than you expect.

@@XPLAlN fair comment. The Velis has normal cruise power tables where we operate at the lower end of those normal cruise power settings - 20-25 kW. The demo flight above seemed to be operating at cruise of 35 kW. In comparison, we do normal climbs at 40 kW. Flying this aircraft needs a shift in mentality - no operating it like a conventional aircraft with 5hrs endurance; it needs to be operated for what it is - somewhere between a glider and an ultralight. It just happens to have full certification. Flight students need flight time - not flight distance.

@@chronikentertainment7856 thank you for the reply. Normal cruise is not defined so I expect low power cruise would be acceptable for the purpose of reserve planning. In the video he said they were using 25 kW at 85 KIAS so on paper that is 12.5 kWh reserve or 57% . A 3 minute climb at max con followed by a 25 kW cruise will in theory result in 20 minutes flight plus 30 minutes reserve, so I think that is the kind of profile that resulted in the times quoted in the video. PB said they flew for 21 minutes and used 43% capacity so theory would seem to correlate with practice in this case.

This dork posted a letter in a KZfaq comment

It's probably a cut and paste of an email. You're the dork here, Glemm

🤣 Self launching glider

..or weather radars.

Dont fly from a busy airport in case you get stuck in a holding pattern.

oil bot detected

100% They best speed is between 64 amd 70 knots. We too clock consistently 1.0s at least. A perfect training mission duration.

This suggests that your motor controller is not compensating for reduced voltage by increasing current. My guess is this aircraft does that.

@@paulogden7417 You're correct, the motor controller doesn't compensate for the battery's power curve. To do so would mean reducing available take-off, and some cruise, power artificially. Some systems may do that but there will be a limit. I was trained to understand the machine I'm operating so it would behoove me to know about both the battery's power curve as well as any electronic compensation system.

That sounds like nonsense to me. It's no diferent to an electric car, you have the same performance available at the start of the drive as the end. I've just done a search and I can't find anything that says performance is less at the end of the flight.

That's not how modern batteries work, the power curve doesn't drop off that fast. Not to mention it's a 50 minute range PLUS a 30 minute VFR reserve. So as you are flying back to the field to land, you're at about 50% total charge, not 20% or whatever.

@@martinw245 you can boost the voltage yes, but a full charged 18650 pack is 4.2v and a spent one is ~3.5v. If you take into account c rates, there’s a reason all EVs are fastest when fully charged it’s simply the voltage being higher at max charge. At 6C a battery cell outputting 3.7v is always going to send less power than a 6C battery at 4.2v it’s just how battery chemistry has evolved.

Indeed.

Battery technology is far from new. In fact it is rather mature.

yeah paul's the man

So far i am aware the did not. Still 45min? But i would love to know where you found this information?

10min for flight in close proximity of aerodrome (also for conventional planes) 30min for VFR crosscountry (+IFR jet) 45min for IFR and night

@@500arend Its in the EASA ruling.

See what @Aviationinmymind said. 10 mins if remaining in sight of airport is not a concession in Europe, it is standard.

@@flexairz i will look it up again 😅 geus my knowledge is a bit rusty

What technology? Everything is mature.. dumb solution

I wonder how Glider Pilots seem to manage with 0 minutes?

The relevant technology is energy storage, which this has nothing to do with. Do the math and you'll see that no matter how much you optimize for drag coefficient, or anything else, batteries aren't even close. The future is almost certainly in turbines burning "clean" fuels, like Fisher-Tropsch derived synthetic liquid fuels from renewable feedstocks or even direct carbon capture to fuel cycles.

10 mins reserve is only valid while flying in the traffic pattern.

I wonder if there are lower weight non-rechargeable battery options for reserves, so the final 15 minutes would never be used.

You could do the math on gas engine efficiency vs EV efficiency. E-cars are around 5x as efficient as gas. A gallon of gas may contain a lot of energy but a gas engine is merely a noisy heater with motion as a side effect at about 25% efficiency... As such, multiply usable energy in a gallon of gas by 0.25 for cars. Planes may be a little better but not hugely so.

@@Kimoto504 gasoline engines are extract about 20-24% of the energy in gasoline. diesel engines extract about 90-95% of the energy in diesel. combustion engine vehicles get lighter as you go further since you're using the fuel up, and you're making the same power. electric crap stays the same weight from start to finish and makes less power the weaker the charge gets. you battery beat-nicks/hippies/whatever need to stop lieing to yourself. electricity is great, batteries are not the option for vehicles. you also completely ignore the fact that mining lithium and other components for those batteries has caused extravagent amounts of damage to the local land. heavy water(irradiated water) filling the whole mine from the process is just sitting around,slowly creeping into the water cycle. wake up, dont believe the crap these people who are taking millions of tax payer dollars from government grants tell you.

OK 32 kWh is 115 MJ which is exactly the same energy as a gallon of avgas. However, this airplane has a max L/D of 15:1 at 64 knots, according to Pipistrel. "Endurance speed" is min power speed which is generally about 0.8 of range speed (aka max L/D) for propeller airplanes and uncomfortably close to the stall in this case so I am going to use the range speed instead. At 600 kg with a 15:1 L/D at 64 kts in standard conditions the power required is glued on at 12.9 kW. Now even if you take 2 kWh out the 22 kWh battery for a climb to pattern altitude you have 20 left, so to burn through that at a rate of 13 kW in 58 minutes would equal an efficiency of 65%. Which is a lot worse than a Tesla. And the problem here is we do not really know what power setting results in the claimed endurance of 60 minutes so the efficiency could be better or worse but it is a stretch to get it higher than eg a Tesla 3.

Planes are often more efficient than cars. A gallon of gas will go further in a plane than the car it came out of.

@@jmwintenn Most diesels are 35% efficient, some commercial trucking engines can do 45% and ship diesel engines can reach 54%. Diesels with 95% efficiency? Not a chance. They'd be near noiseless and not need cooling systems if they could get that efficient.

That is the case with cars too. Not so much with range, but charge time. Charge time may be less of an issue with flight schools or for that pilot who likes to fly on the good weather weekends. But with current battery tech, a lot of capability just isn't there.

@@randallkelley3600 True although cars can worry less about the weight issue. Many electric cars are on par with their gas-powered counterparts in terms of range now. Always room for improvement of course.

@@randallkelley3600 Meh - The newest Model 3 with 60kWh LFP battery would be enough for like 95% of people driving. Goes like 250 miles with a charge, has good durability and good charge rates. On average people only drive like 25 miles per day.

I'll happily buy an electric car when the charge times significantly reduce and when the cost of batteries drop significantly. Maybe when by 2020 Tacoma hits 300k miles battery tech will be where it needs to be.

@@CarterHancock Now if they can just get charge times down.

CO2 is plant food not pollution and not a significant "greenhouse" gas.

It will dominate at some point. Instant torque is so wonderful.

Well, can't do that anymore. The only completed An-225 was destroyed.

Don't be ridiculous. That is just silly. A C-130 would be more than capable of carrying that kind of load. No need to talk about the An 225.

Finally, someone with practical solutions. Great idea.

It is do-able. Military jets routinely have less than a 10 min reserve. Sometimes not even enough for one more cct.

May that traffic pattern not be over my house. Bonus, let the traffic pattern be over those for electric planes. Thanks.

@@glynnetolar4423 Right now it seems that the only real dangerous airplanes are gasoline powered.

I agree. I’d love to fly touch and go circuits in this.

You can get pretty far with 36 minutes of flight time though... Not across the atlantic, but..

The technology is getting there but clearly has limitations. The certification in Europe helps with the intended use case of a trainer that mostly just stays in the pattern. For that, 10 minutes reserve is fine since you are basically within gliding distance of a perfectly good runway. Which is why they can stay up for fifty minutes or so. This plane is obviously never going to be breaking any records. But if you look at it as an early MVP, it's not that bad. It works as advertised and they are popular with flight schools in Australia and Europe. The main opportunity for improving this design is that the batteries in this thing are simply not state of the art. Not even close. A lot has happened in the last 5-10 years. The issue is that replacing batteries resets the clock on the certification by several years. So, they entered the certification process quite a few years ago with whatever had been available then for some time (i.e. they chose suppliers conservatively). E.g. the Nissan Leaf more than doubled its range in the last 12 years without increasing the weight. The first version from 2010 had a 21 kwh battery. There now is a 62kwh version and the smallest version is 40kwh. People are swapping out the batteries in the original leaf and are getting double the original range. That might happen with Pipistrel as well eventually. Both weight per kwh and charging times could probably be improved quite a bit even without switching to e.g. solid state batteries (which are actually becoming available now). So, if they'd manage to go from 50 to 90-100 minutes, that would be nice upgrade and they might be able to improve on that as well. Also getting the charge times down should be feasible. There are EVs on the road that charge much larger batteries in a fraction of the time. And with the extra range, you could afford to only charge to about 80% instead of having to wait for 100%. Charging to 80% is usually quite fast with EVs. Other manufacturers have similar issues with their batteris but are doing a bit better despite similarly lagging in battery tech. E.g. Bye's Eflyer 2 is currently undergoing certification and is rated for a 3 hour endurance. It had it's first flight in 2018 and it supposedly might get through the certification process by next year. Likewise, the Eviation Alice has a range of around 500 miles. So, it's not there yet. But getting there is not exactly science fiction any more.

@@rkan2 No. Not really.

It's not there for planes yet. But it wasn't there for cars 15-20 years ago either. The first modern EV cars were completely impractical, just like this Pipistrel is, but without them we wouldn't have gotten to where we are today. The Pipistrel isn't the end game, it's a first step.

@@maxleitschuh7076 Air travel is vastly different. Unless or until we have a revolution in battery storage density and weight, then EV for airplanes will not be going anywhere.

Well said!

If you pay 10$/gallon - probably in many situations yes

​@@rkan2the amount of fuel you need to burn to offset thay price difference exceeds the life of the battery.

@@Blxz A Model 3 costs 30k$ used 40k$ new. 5L/100km The car would consume that much after 300/400 thousand km at 2€/L. The electric car will probably be at least twice as valuable after it has driven the same distance.

@@rkan2 huh? This is a video about planes right?

These electric aircraft doesn't really benefit anyone apart from the environment, and for niche applications like general aviation it will probably be cheaper to just pay a carbon tax and plant more trees. The move towards cleaner-burning fuels and exhaust filters would also make the transition to zero emissions much less urgent, and the impending end of Avgas will force owners to re-engine their aircraft. Aviation grew because of the obvious benefits of faster travel (as well as military uses), whereas with electric aircraft it's like replacing plastic straws with paper straws, it's an inferior solution that's better for the environment. But there are other ways of achieving the same for the environment - plant enough trees and GA could become carbon negative.

@@Avantime electric planes/cars are not better for the environment. CO2 is plant food.

@@Avantime Let's not forget that an electric motor is probably 10X more reliable than a gasoline engine. There are limitations but when it does happen it will be better than a gasoline powered aircraft in just about every way. There will be no ignoring it then. Its simply inevitable.

@@lamberto6405 The problem is you can't have an electric motor without a battery, those two must come together. (Well technically you can have a gasoline/diesel-electric engine but that's just adding needless complexity, the crankshaft is ideal for driving a propeller) Once you add a battery you'll need an aviation-certified battery thermal management system. It's this part that will most likely fail, with potential catastrophic consequences such as a runaway battery fire, a sudden collapse in range, or the engine and avionics stop working. High capacity, lightweight batteries are especially volatile, and aircraft can't just go into turtle mode. Internal combustion engines and gas turbines have been around for around a century, and manufacturers are very good at making reliable engines. Today you wouldn't bat an eye on a Toyota with a million miles, or a Rolls-Royce jet engine reliable enough to carry an ETOPS-certified 777 for almost 4 hours on a single engine. It's the GA mentality that's holding the scene back towards much more reliable, modern engines. Electric aviation still have a lot to prove, the industry is still very much in the pioneering era. Give it 50 years or so, as technologies get mature enough to meet the safety standards aviation regulators and the flying public demands. You see all those futuristic electric flying taxi start-ups valued at crazy amounts of money? They'll all disappear when the Fed raises interest rates back to normal levels in order to control inflation. In order to control inflation, the interest rates must rise over the rate of inflation, like 8% to 10% now. And the later the Fed does it, the more they'll have to raise rates, as wage increases spiral in response. Tesla's stock is already down ~50% this year, with the current Fed funds rate is just 1%.

with the deep discharging aviating would generally involve and fast charging battery life of 2000 cycles is optimistic

You wouldn’t get cold enough in 18 minutes LMAO

interesting idea

Amen to that

The amp accounting comes straight out of the BMS. You are correct, to put back in the stated 12.5 kWh or so, it required nearly 14kWh of input. The value stated in the video was correct, although needed that additional context.

Hydrogen storage is a nightmare. The tank system has to be thick to hold the pressure. It takes 1kg of tank to hold 0.090kg of H2.

I was wondering how much the cold weather performance would suffer. University of North Dakota's flight school probably couldn't use it.

Exactly right!

I wouldn't say it is the only utility, especially with battery power... Solar powered however, I think it is a bit unexplored idea, even if they did cirumnavigate the earth with one already.

solution: flying trolleybus

@@RoamingAdhocrat well... there was company who had that solution in mind anyway

It is mature right now.

How is it mature now, when you can only fly for 20 minutes with a 30 minute reserve? I don't call that mature.

@@HeyIFoundACamera You could say that’s mature, just impractical with the limitations of power source. If they invented a new magical cheap power source/battery tomorrow that you could swap in for the batteries, the rest of the tech is pretty solid. I’m curious why they’re not looking into hybrid systems in the mean time until solid state batteries are economical power density wise.

An the surface, yes. But it would require hoses, valves, a radiator in the cabin. Say, 25-30 KGs easily. With the margins being as thin as they are, that's probably why they chose not to implement that. Someone more cynical than me might even say that you probably won't get very cold in 21 minutes anyway 😉 In any case, an interesting airplane, that shows a probable future. My local airfield has one, I might call them sometime, and ask what a flight would cost (as a passenger, not a pilot) just to experience it.

No. It takes great power to generate heat so its planned that way. Engines create "free" heat thanks to their inefficiency but it is an ancillary benefit.

Fly powered gliders....

That's true for internal combustion engines but not so for electric and external combustion

@@frontagulus No, it's true for absolutely everything. It literally can't be any other way.

Indeed, in aircraft thrust is what counts. And it explains why the performance in flight is no better (worse I think) than the Rotax powered version

@@randallkelley3600 Yup, the takeoff run for the Velis is well more than twice as long as the Virus. Vehicle performance is all about power to weight ratio.

@@frontagulus Absolutely right. According to the fourth law of thermodynamics "horsepower equals torque times RPM divided by 5252 except for electric and external combustion engines". Also, for electric and external combustion engines, 2 + 2 = 6

It has a one hour endurance, plus a tiny reserve.

Yeah, and that European certification with 10 min flight reserve...better not have to go around or divert to a different airport.

​@@randallkelley3600 EASA's 10 min of reserve applies to all aircraft, as long as they fly in close proximity of an aerodrome = traffic pattern training

Battery technology has been mature for decades, they are using batteries that have been in existence since that last century.

LOL!!

It is a little different with electric propulsion. Unlike fossil fuel engines, the electric motors are not running (using power) when stationary when waiting in line on the taxiway.

I wonder how much battery power will be waisted doing the run up lol

This airplane requires a battery overhaul at 700 flt hours so your estimate is inline with the EASA decision based on whatever Pipistrel showed them.

Till they are not.

My experience is electric cars are very excepted in the enthusiast car markets now. You see Tesla’s at the drag strip being driven by middle aged dudes in cut off t-shirts. Fast is fast. People are loving the new Porsches too. Only gripe is the sound being boring, I don’t see formula 1getting rid of ICE’s for instance because the soundtrack is a big part of the drama and excitement to spectators. Some of the new models have more active sound generators though and eventually they’ll figure out how to make them as raw feeling for those that appreciate that about cars.

One hour and thirty minutes reserve in UK. A flight school already has them. Don't worry, Toyota's prototype solid state battery production line is being built, as is Solid Powers. There's a Toyota driving the streets now with a solid state pack. In an aircraft you are talking about less weight, more range, faster charge