Test ride in Pipistrel electric plane

[facthunter]

Max re gen is shown as" recuperation power"( A somewhat strange term) which is shown to be about the same RATE as "full power" uses. but that would vary and only be the max amount if you did a deliberate and positive action to allow it to happen.. That would have to have a large effect on your glide angle as you cannot get energy for nothing.

 

There's no mention of energy (KWh )USED on Take off run or on downwind. either.

 

45 Kw is about 60 HP which is certainly not overpowered.. so it's not going to roar off the ground and climb like a homesick angel. They are a pretty clean aircraft so probably quite suited for this type of propulsion. Also I've NEVER said the idea is ridiculous. What I AM saying is the regen effect is not a game changer. THEIR own figures show 3% for the best outcome and 1% for the other two. The engine's propeller DRAG could slow the plane significantly or steepen the approach path without flaps IF you are able to select a large regen figure.. The flaps extended situation could be quite interesting as you are now in a full flap extended glide with NO forward thrust, but an opposite direction extra drag equal to the normal thrust in magnitude.? If this is possible it's certainly going to be different.. Nev

 

 

[octave]

IF you are able to select a large regen figure..

My understanding is that you do not and cannot perform an action to select the amount of regen you get other than by pulling back power all the way and pitching down. In the video, the instructor points out to the person under instruction that you will hardly notice it except the power usage meter will go into negative numbers. One thing I totally agree with you on though is that the amount of charge is not that impressive. We are not talking about huge amounts of power here. As a range extender, it is not all that impressive. The study that I quoted was from a study using a converted Cirrus sr22. They managed 5.4% but they did not see this as a game changer. My prediction would be that either Pipistrel will improve the efficiency or perhaps drop it. I think if I purchased one with the option I would take it if it was no too much more.

 

It may also be useful in aircraft that require air brakes but that is something I am not so familiar with. I note that the Pipistrel Virus (piston) does come with airbrakes.

 

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Look I think we are not necessarily saying much that is radically different. Regen will either improve or it will be one of the many ideas tried and rejected but just at the moment it is still in the game and being studied from NASA down to Pipistrel.

 

[octave]

This looks interesting but quite long, I have only just started watching so no idea of the content

 

 

[Bruce]

Only a few years ago, the idea was that lithium batteries were too dangerous to consider. Now we are discussing a detail about how they can return some energy on descent. Progress huh?

 

Personally, I have used a LiFe battery to start the Jabiru for years now, but at first I felt it wise to keep quiet because some people thought this was dangerous. I tried to explain the differences in lithium batteries, and I tried to explain how lead-acid batteries were not without risk too. In particular their weight is a bad feature.

 

It must be the adoption of electric cars which has influenced safety authorities to allow electric planes. I'm surprised they are not fighting a rearguard action to stop them.

 

On the regen, on the figures in octave's post, it's not much energy saved.

 

Here's a bigger thing to be concerned about... How does the battery pack perform with age? I know that with r/c models, the battery is at its best the first time you use it. Guys use their old packs for practice and a new pack for a competition.

 

If the pack is used at its max power ( as seems reasonable for take-off ) then a small loss will be very noticeable.

 

 

[octave]

How does the battery pack perform with age?

Yes that is the crucial question. The operating costs are very low however you have to compare the lifetime cost. I guess we need the batteries to last as long as the typical combustion engine. By the way the vid I just posted which interesting but a little dry suggests that traditional props are not very efficient as a turbine but symmetrical, multi bladed props (5 6 7 or 8 blades) regen becomes extremely efficient.

 

 

[Litespeed]

Regent debate aside....

 

It will not be long before solar covered wings with minimal weight are used to recharge. As long as there is daytime, you have some power. A bright cloudless day you have a handy amount to augment the batteries and greatly increase range.

 

We are world leaders in solar research and have been for 30 years. We now have the ability to print a solar cell onto a plastic film. As efficient as a heavy old gen cell but will only improve. Its not much heavier than a laminating film. As development continues it will be much higher efficiency and even cheaper. Its uses basically a jet printer modified.

 

100 square feet as a example can provide a lot of charge and a suitable design with lighter batteries which will happen, is a exciting prospect. Long winged solar and battery aircraft have a big future. In a motor glider configuration, range at suitable speed could be very long. Then land and recharge from the sun. Add a small fuel engine to augment range when needed and we might see 4 LTS hr or less at a nice 120 knots. The small engine runs at high efficiency only when needed for boost power such as takeoff , low settings for cruise or charging. It can be wherever design and c of g dictates. A much smaller tank of say 40 litres and you could still go a long way.

 

The pipestrel was using only 3o HP or less with good speed. A optimised hybrid with solar could get that a lot lower.

 

I can imagine 120 knts cruise and 1200 nm. On good conditions lift would mean extended fuel free periods on battery/ solar power or no power.

 

The future has come for our dinosaurs

 

 

[octave]

Regent debate aside....

It will not be long before solar covered wings with minimal weight are used to recharge. As long as there is daytime, you have some power. A bright cloudless day you have a handy amount to augment the batteries and greatly increase range.

 

We are world leaders in solar research and have been for 30 years. We now have the ability to print a solar cell onto a plastic film. As efficient as a heavy old gen cell but will only improve. Its not much heavier than a laminating film. As development continues it will be much higher efficiency and even cheaper. Its uses basically a jet printer modified.

 

100 square feet as a example can provide a lot of charge and a suitable design with lighter batteries which will happen, is a exciting prospect. Long winged solar and battery aircraft have a big future. In a motor glider configuration, range at suitable speed could be very long. Then land and recharge from the sun. Add a small fuel engine to augment range when needed and we might see 4 LTS hr or less at a nice 120 knots. The small engine runs at high efficiency only when needed for boost power such as takeoff , low settings for cruise or charging. It can be wherever design and c of g dictates. A much smaller tank of say 40 litres and you could still go a long way.

 

The pipestrel was using only 3o HP or less with good speed. A optimised hybrid with solar could get that a lot lower.

 

I can imagine 120 knts cruise and 1200 nm. On good conditions lift would mean extended fuel free periods on battery/ solar power or no power.

 

The future has come for our dinosaurs

 

Last night I did a deep dive into talks from the sustainable aviation foundation. It gave me a sense of optimism to see that smart people are working in the background on these issues.

 

Loads of interesting presentations here. It takes a bit of commitment to watch all of these talks but even a bit of skip through some of them will show the interesting research and projects being undertaken.

 

Sustainable Aviation Foundation

 

The chief designer from Pipistrel gives a talk about his involvement with the MAHEPA (Modular Hybrid Propulsion Solutions). It does look like hydrogen may be the future of passenger aircraft.

 

I see that Pipistrel has supplied NASA with electric motors for the x57 project.

 

Interesting times

 

 

[spacesailor]

"Add a small fuel engine to augment range when needed and we might see 4 LTS hr or less at a nice 120 knots. The small engine runs at high efficiency only when needed for boost power such as takeoff , "

 

OR go Hummel. 61 mpg @ 100 mph. That's what the aim is ?..But first "SACK CASA" .

 

"It will not be long before solar covered wings with minimal weight are used to recharge "

 

at 700 SQUARE FEET a trike should have enough area to solar power itself without batteries !.

 

Take out the weight of it's Rotax 582 motor, then the fuel. 64.4lbs / 29.2Kg, fuel 66.lbs / kilogram29.96. = 58.5 Kgs, Should only need a small motor.

 

spacesailor

 

 

[facthunter]

A solar plane has already flown around the world.. Nev