Pipistrel $1.3M prize

[bwilson4web]

Thanks Frank,

. . . But grousing about how it's [electric aircraft are RJW] unfeaseable won't ever make it happen.

I was thinking about this going to sleep last night:

• electric engine assist - my 60-65 hp VW engine would be helped with an additional 12-15 HP during takeoff. The additional electric torque would provide the extra rpm to allow a climb prop to get off and climb high enough to lower the nose and get the speed up. So back-of-the-envelope looking at say 15 HP / 750 w/hp ~= 20 kW for about 120 seconds, or ~0.8 kWh. Round it up to 1-1.6 kWh for longer battery life and we're talking about a reasonably light weight Li power pack. The Buick e-assist has a 15 HP motor generator about the size of an oversize alternator that with gearing could also be the starter.
• motor-generator wheels - provide the electric assist during the takeoff run to shorten distance and regenerative braking with ABS and traction control during landing . . . the end of hydraulic brakes.

But I'm not headed that direction . . . yet. I have more immediate goals and objectives with my plane.

Bob Wilson

[steveinindy]

Steve, for several days after they can be seen flying in long rows and waggling their wings before landing on three regularly spaced locations, and their songs turn into low octive rumbles.


This is replaced by furious pecking in a rectangular area, which ornathologists have posited might be a means of expressing their frustration at the high price of water, squirrels running around too fast in no-squirrel zones, and the overabundance of hawks, eagles, and other birds of prey.

...and this is why I like you Frank.

[steveinindy]

IF there was an electric option that had the power, weight, and range of petrol engines that were also economically viable I'd probably bite. We're not there yet.

But grousing about how it's unfeaseable won't ever make it happen.

I don't think it's unfeasible. I just don't think as a 31 year old I will see within my lifetime electric propulsion with those criteria for anything but the UL or LSA classes.

[Jim Hann]

I don't think it's unfeasible. I just don't think as a 31 year old I will see within my lifetime electric propulsion with those criteria for anything but the UL or LSA classes.

Remember Orville Wright's lifespan saw man exceed the speed of sound. Never say never.

[bwilson4web]

Remember Orville Wright's lifespan saw man exceed the speed of sound. Never say never.

Indeed! There are refactory temperature fuel cells (Google up "Molten Carbonate Fuel Cells") that if the materials can be worked out could run off of coal or really crappy hydrocarbons (aka., bunker oil anyone?) For peak efficiency, the cooling air would be from a compressor and the heated air exhausted through a turbine. . . . It isn't trivial nor around the corner but this is the one fuel-cell path that is not to be confused with the various fool-cell programs in the recent past. - Bob Wilson

[steveinindy]

I'm not saying it's impossible. I'm just looking at the odds of it happening within a given time frame. If I were told to bet money on it, I'd say a plane the size and with the performance and reliability of a Cessna 172 is a good 15-20 years out at a minimum. A commercial aircraft? Probably 50 years out if at all. We are simply at the same gap between a functional GA airplane powered by electric propulsion that the average pilot would consider useful as the folks in 1903 were from the Bell X-1. We are also not likely- especially given the conservative suspicion of environmental science and its push for green technology that pervades large portions of American society including the pilot population (which is surprising given how well educated a lot of pilots are)- to encounter the electric aircraft equivalent of the developmental stimulus that was World War II. I recall a history of the development of supersonic flight lecture by one of the Bell engineers who worked on the X-1 in the late 1980s that I attended (one of his proteges was a member of the congregation I was part of at the time so I was taken along for the presentation) who made the comment that without WWII, it probably would have been an additional 10-15 years before supersonic flight in straight and level flight was achieved.

Also, I would tend to point out that there is a difference between breaking the sound barrier in a single seat research aircraft and having something practical in service. It took another six years to see a supersonic fighter (the F-100) and twenty-two years before a practical* civilian application was developed and put into service (the Concorde).


*-Practical being an arguable choice of words here.

[Floatsflyer]

As much as I get accused of being too negative about electric aviation, I would tend to agree with you there. Research is always a good thing as long as it is done in a valid and scientific manner.

That said, I am really getting tired of politically based threads like this on here. I'm reasonably certain that when the switch was made from whale oil to electricity, those with a stake in the whaling industry put out all sorts of negative commentary about their competition. Nothing new under the Sun.

Hey Steve, don't want to burst your idealic bubble, but everything is politics, everything is political because of competing interests and differing points of view, correct or incorrect, intelligent or ignorant. Non-BS is what we should all be striving for. The pure definition of politics is the allocation of scarce resources. And speaking of scarce resources, fossil fuels from this good Earth will be tapped out in about 100 years from now so our reliance on oil must be replaced quickly by new innovations and technologies in new energy sources that are taking place now and into the future. Our continued existance as human beings is dependant on it. You could look it up!

[steveinindy]

don't want to burst your idealic bubble

LOL You don't know me well at all if you think I'm at all idealistic.

The pure definition of politics is the allocation of scarce resources.

Actually, that's the definition of economics as well.

Non-BS is what we should all be striving for.

That's what I was getting at but then one side or the other contests the evidence and it goes right back to being a massive swirling cloud of ****.

so our reliance on oil must be replaced quickly by new innovations and technologies in new energy sources that are taking place now and into the future. Our continued existance as human beings is dependant on it. You could look it up!

Oh, I agree completely. I just don't believe that we are going to see electric aircraft replacing internal combustion engines anytime soon (except for the extreme low end of the ultralight and light sport bug smasher crowds). We are far more likely to come to rely upon biodiesel or something like that. However, making such suggestions tends to turn into the "Keep your ethanol out of my gas! Y'all hear? *shotgun being racked*" sort of debate. I try to stay away from alternative fuel discussions as much as possible in circles (such as this forum) where I know the slant is distinctly "conservative" (said as a moderate Republican). It just does not end well.

[tdm]

Barring any unforeseen rapid advances in the energy density of batteries, I agree with the majority of posters here. I think all electric aviation is not currently practical nor does it appear to soon be practical. But I don't think the current powerplant technologies utilized in general and even commercial aviation represent anything resembling an apex of development!

Internal combustion engines, turbine engines, and even fuel cells could all benefit from combined cycle (combined power and power) additions, if the weight of such a recovery cycle could be made practical. With the rising price and likely future scarcity of high octane gasolines, general aviation engines burning diesel (taking Diamond aircraft's approach with the DA42), or even burning natural gas or methanol could become practical.

And with commercial aviation, any increase in the thermodynamic efficiency of a high burn efficient turbofan, combined with aerodynamic improvements, such as contra-rotating fan and pitch control fan, I think could pay for their development costs quite nicely, especially with today's fuel prices.

All electric control systems, however, on larger aircraft combined with increasingly powerful batteries, I think are ready to replace hydro-mechanical servocontrols, right now and with current technology. (Clever electromagnetic shielding and redundancy would have to be engineered in of course, for safety.)

Overall, I hope, (and expect, (perhaps (probably) over-optimistically)) that the average general/small commercial aviation aircraft manufactured 15 years from now will be vacuum/pneumatic/hydraulic system free, completely solid state glass instrumentation, all composite airframe, and not a vor or adf in sight. And with an extremely efficient cheap natural gas burning combined cycle FADEC engine. (Now I'm dreaming..)

Or we will still be flying aluminum avgas burners..

[Joe LaMantia]

Nice Discussion!

I'll add my 2 cents by advocating that a possible solution may be coming from research being done on "bio-fuel" produced from algae. There is a project underway where tanks of algae are located at a coal fired power plant. The algae feeds on CO2 which is captured via the coal burning process, so this maybe a practical way to produce electricity, provide a viable replacement for oil use in vehicles and be CO2 neutral. This isn't some futuristic pipe dream it is actually being done on a small scale. I don't know anything about the economics of building or operating this system but on the surface it would seem to be a simple capital improvement that creates a completely new source of revenue for power plant operators. This could be the American Innovation we are all hoping to find. I'm staying out of the politics, change always brings conflict.

As for electric planes we have seen some early examples which so far don't provide a practical solution that would replace the current fleet. I like reading articles that bring these innovations to light, it's just a continuation of the advancements in aviation we have seen since the Wright Bros.

Joe