Use the DA-40 as an example. Long wing, flies with fairly minimal power.
Carries a decent amount....

Tim

Just a side comment: Finding ways for people to meet the ATP requirements cheaply is great on the surface. However, the point of the hour requirements is to have a breath and depth of experience that serves as a foundation for a pilot flying hundreds of passengers in an airliner. I will never believe that circling around in perfect VFR 10 hours a day in a powered glider, while going nowhere, is going to make you anything but a poser.

Cells can reach 250 WH/kg. Battery packs can't when you add the wiring, safety circuits, and mechanical structure to hold the cells.


Link to commercially available solar cells or panels that do 30% or greater. Remember you said they could be had "easily".


Increases weight since you need better cell cooling, heavier wiring, larger circuits pathways.

Mike C.

The ATP requirements are a joke for airlines. Congress stepped in and created a completely BS requirement to look like they were doing something.
The reality is training is expensive, and the logistical burden to have pilots and airlines actually do truly effective training would be complex and likely cost as just as much. For example, a smarter regulation would have created regions of the country where you must train and be certified to deal with specific conditions that caused the Colgan crash. e.g. You cannot take a pilot that learned to fly in Arizona and make them a pilot flying around Boston in Winter without some ice training.
But this is way to complicated, to many variables, how do you test it..... For Congress to actually get correct. So they went the easy way.

So for now, the industry is looking for ways to complete the checklist as cheaply as possible.

Tim

"Time Builder"? I have flown for a looooong time. I never once improved my skills sitting behind a yoke or stick watching the clock. Like sitting behind an autopilot in IFR weather, useless as far as a skill improver. More benefit from ten current approaches than a thousand hours of "riding along with George".

I have known scores of 15,000 hour ag pilots who couldn't survive ten minutes in the clouds and highly skilled instrument pilots who couldn't taxi a Cub to the runway without taking out taxiway lights.

The "skills" of flying are many and varied and barely related in some cases. Any "airplane" with capabilities as limited as this electric bird will offer a modicum of useful learning experiences and even less practical utility. The hype, promotion, and failed promise of the regeneration of aviation training as a result of LSA's is an example of "high hopes and low reality". At this point, electrics simply fall into step behind that last great promise.

The technology of electrics is evolving at an exponential rate, but as for practical use in airplanes, it is still "beyond our vision".

On a more positive note, they did find all those buried Spitfires didn't they?

Jgreen

Takes 90 HP (67 KW) to keep the DA40 flying at the best possible speed.

2 hours of that requires a 134 KWH pack.

At 200 WH/kg pack energy density, a so far unachievable number, that is 670 kg, 1,480 pounds.

The present empty weight of a DA40 is 1,800 lbs.

Doesn't work.

And that was cruising at exactly the minimum drag airspeed. Do anything else and you get less duration.

Mike C.

Great post Tim. I'm a dreamer. Funny part was I looked at the article I posted, saw the picture, saw the airplane and started to dream about the possibilities........an engineer I am not

The ATP requirements are a joke for airlines. Congress stepped in and created a completely BS requirement to look like they were doing something.
The reality is training is expensive, and the logistical burden to have pilots and airlines actually do truly effective training would be complex and likely cost as just as much. For example, a smarter regulation would have created regions of the country where you must train and be certified to deal with specific conditions that caused the Colgan crash. e.g. You cannot take a pilot that learned to fly in Arizona and make them a pilot flying around Boston in Winter without some ice training.
But this is way to complicated, to many variables, how do you test it..... For Congress to actually get correct. So they went the easy way.

So for now, the industry is looking for ways to complete the checklist as cheaply as possible.

Tim

Takes 90 HP (67 KW) to keep the DA40 flying at the best possible speed.

2 hours of that requires a 134 KWH pack.

At 200 WH/kg pack energy density, a so far unachievable number, that is 670 kg, 1,480 pounds.

The present empty weight of a DA40 is 1,800 lbs.

Doesn't work.

And that was cruising at exactly the minimum drag airspeed. Do anything else and you get less duration.

Mike C.

Calculated from climb rate, gross weight, and horsepower.

The best climb rate is achieved at the minimum drag airspeed. This leaves the most power left over for climb.

For the DA40, the gross weight is 2,645 lbs and the climb rate is 1,120 FPM. To raise 2,645 lbs up 1,120 ft in 1 minute takes 90 HP (1 HP is 550 ft-lbs/second).

The DA40 has a 180 HP engine. 90 HP is being used for climb, 90 HP is left, that is what it takes to fly at Vy (which is min drag) and remain at altitude.

If you fly slower or faster than Vy, it takes more power to fly level.

The above doesn't take into account prop efficiency, but close enough.

DA40 numbers from Wikipedia page.

Mike C.

Calculated from climb rate, gross weight, and horsepower.

The best climb rate is achieved at the minimum drag airspeed. This leaves the most power left over for climb.

For the DA40, the gross weight is 2,645 lbs and the climb rate is 1,120 FPM. To raise 2,645 lbs up 1,120 ft in 1 minute takes 90 HP (1 HP is 550 ft-lbs/second).

The DA40 has a 180 HP engine. 90 HP is being used for climb, 90 HP is left, that is what it takes to fly at Vy (which is min drag) and remain at altitude.

If you fly slower or faster than Vy, it takes more power to fly level.

The above doesn't take into account prop efficiency, but close enough.

DA40 numbers from Wikipedia page.

Mike C.

For anyone who has read my earlier posts on the advantages of renewable energy may be surprised by this one.
Static solar arrays are efficient and effective. One must consider, however the latitude of the array so that it may be tilted to the angle of max efficiency and must account for the distance from the equator due to light lost passing through the atmosphere. Clouds, haze, etc. are considerations as well. Hard to do in aviation. I can't for the life of me see the usefulness of PV cells on an aircraft- particularly those used to recharge a battery bank to power the engine. Because of w/b concerns, the batteries would have to be at the CG, meaning that occupants would have to sit above or below considerable weight. I'm not sure how much of this weight could be placed in the wings if any at all.
My belief as electric power is more frequently proposed for untethered vehicles is that, for many of the reasons listed in preceding posts, it is currently unrealistic. Solar, wind and falling water generated electricity has many benefits which are not currently being exploited fully, but untethered locomotion is not yet one of them. Automobiles are progressing, but aviation is still a dream.

Did not see your earlier post. In re-reading the article from my original post I see the pv cells on the wings. I was more excited about the possibilities of electric airplanes than the actually charging said airplane with pv cells on the wings.

The possibilities (if we put Mike C in charge of research) of electric propulsion are exciting.

The ATP requirements are a joke for airlines. Congress stepped in and created a completely BS requirement to look like they were doing something.
The reality is training is expensive, and the logistical burden to have pilots and airlines actually do truly effective training would be complex and likely cost as just as much. For example, a smarter regulation would have created regions of the country where you must train and be certified to deal with specific conditions that caused the Colgan crash. e.g. You cannot take a pilot that learned to fly in Arizona and make them a pilot flying around Boston in Winter without some ice training.
But this is way to complicated, to many variables, how do you test it..... For Congress to actually get correct. So they went the easy way.

So for now, the industry is looking for ways to complete the checklist as cheaply as possible.

Tim

Regarding time building. The people recently hiring 250-500 hour guys into RJ FO positions are going to be perfectly happy hiring 1000 hour guys with 500 hours of SunWarrior time.

The easiest way to an ATP now is 1000 hours and a 4 year degree. If a college can find a one seat plane that will run at $5/hr DOC they can offer a package flight training deal that puts you out the door at 22 with an ATP at an "affordable" price. Is it a good idea? Does it make you a good pilot? Who knows, doesn't matter. The issue is what you can sell to 18 year olds with student loan money. And 500 hours for $5,000 will sell.