Lance,

A few points.

• Most fuel trucks only pump between 2-4 GPM. Not 30 GPM.
• If looking at energy factors, you only convert about 30% of fuel to energy, versus the battery you convert about 90%. So electric you only need about 1/3 of the total energy.
• I looked at purchasing a flight school, twice. One in Maryland and one in Florida. Both flight schools rarely had the plane so booked that there was a five minute turn around. Most of the flight schools could probably get away with one, maybe two spare power packs for every two planes.
• Watch the video, you will see they have a 10kW charging station. And this is for a 1 hour charge. No 4ft diameter conduits.

Tim

Pipistrel are one of the few innovators in aviation today. May their future paths be covered in gold.

No way. I have two 12V pumps for my portable avgas tanks. One pumps 12 GPM and the other is 15 GPM. No way the fuel truck is pumping only 2-4, that would take 8.5-17 minutes per tank on my plane. That clearly isn't happening. At a minimum they're doing the 15 GPM my pumps are doing, probably 20 or better.

I have a flight school with four airplanes. We do a lot more than just stay in the pattern. What airplane do you you do a long cross country in? Swapping batteries is a non starter for me at a flight school. I would love to buy one personally, but I believe the battery technology is the big hurdle.
Kevin

This design is best suited for somebody like Embry Riddle. 20 Electra's, 20 gas planes.

How is swapping batteries worse than refueling?

.....love that quote


I agree, they're innovating. Electric airplanes are a coming. Flight training will be the first step.

I'm also wondering how noisy they are. If they are much quieter......an added benefit.

This design is best suited for somebody like Embry Riddle. 20 Electra's, 20 gas planes.

How is swapping batteries worse than refueling?

No way. I have two 12V pumps for my portable avgas tanks. One pumps 12 GPM and the other is 15 GPM. No way the fuel truck is pumping only 2-4, that would take 8.5-17 minutes per tank on my plane. That clearly isn't happening. At a minimum they're doing the 15 GPM my pumps are doing, probably 20 or better.

Quoted opex is 1/3 of a 152. Sounds compelling to me.

Refueling is done by the FBO with a phone call in five minutes. Who is changing the batteries? I need to have a charging area and employees to change batteries. These batteries are not lightweight, so not just anyone can do the swap. It is more downtime and attention to a new problem. Embry could pull it off, but not sure of the savings long term.
Kevin[/quote]

I'm not in the airplane training game. But I've gotta believe that electric will be way, way easier to maintain than a combustion engine. No oil, no plugs, no cyclinders,

IN high use, the savings will be there. As Charles noted, 1/3 of the opex of a 152 is a great start.

Battery innovation is happening at an amazing rate - it comes close to tracking Moores law (doubles every two years). So if that happens, in a few years you could use this for a typical 1.2 hour lesson with good reserves. It is new so I'm sure they'll find some bugs but once those are worked out, it should be tons more reliable than a piston powered plane.

Got to think it will be quiet too. Students and instructors will have a better environment for learning/teaching. One of the things I notice in teaching is - it is hard for a new student to keep up with the airplane in the pattern and you can only slow things down so much. Being overwhelmed is not a benefit for learning. It would be much better to master the process with an easier airplane and increment up - I think this plane is going to do this!

In 1991 best LiIon cell was 88 Wh/Kg, now it is 248 Wh/Kg 24 years later and improvements are harder and harder to come by.

Numerically, this is an increase of 1.1 every 2 years, NOT doubling.

Batteries are NOT following Moore's law and never will.

Mike C.

Here's a flight in the first Norwegian registered Pipistrel Electro. Notice how the plane uses only 22kW of power cruising at about 90kts. That's about 30hp, which seems extremely efficient. Imagine now, you were up at FL280, that would translate to about 148kts TAS, using only 22kWh. You could see that with a little small turbine APU generating maybe something similar in a hybrid config, and/or in combination with slightly more battery capacity, you can see this becoming a viable alternative in a few years even with the low power density of batteries of today.

Pretty cool bird.

[youtube]http://youtu.be/vgdj9HpdzvI[/youtube]

Hate to bust your bubble but that's not how the whole altitude vs drag vs IAS vs TAS thing works. See the thread on the 3600nm range experimental for way more math about it than I can reproduce here.

Unfortunately I don't think it will work that way. If you're flying at the same IAS (same drag) up high where the TAS is 20% higher, the power required will also be 20% higher.