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gasman

Well Known Member
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If you are building an open cockpit 3 for local flights but worried about the price of fuel. Think about electric!! There will be many new and exciting things coming out in the next two years that will change the way you make that evening flight. And the RV3 platform is a good fit for it.

Complete the three cowl with a loaner O320 and stock mount. Then you will have that option in the future. The electric conversion will place the prop in the proper location. Batteries will be carried on the firewall fwd to true balance. The fuel tanks will be built to carry the remaining batteries.

So what do you get? An almost no noise, no vibration, perfect balance always, almost no maintenance thrill for pennys per KWH.
 
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bkthomps said:
ironic username given the post content
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I thought the same thing. "Gasman" is in favor of an electric RV?

As to electric propulsion for the RV-3, I would hope to see it in my flying lifetime. The Chinese seem to have a leg up on us right now. But like Doug's RV-15, the pilot of an electric RV-3 would have to be content to fly within a set radius of his/her base airport. At least until battery technology advances even beyond its present state.

Airplane design is a very sophisticated set of compromises. :rolleyes:
 
RVbySDI said:
Just some food for thought concerning electric propulsion, here is a link to some news information concerning recent breakthroughs with battery storage capacities:
http://news.cnet.com/8301-11386_3-57384864-76/startup-envia-battery-promises-to-slash-ev-costs/

Here is the link to Envia. They are claiming to have achieved a major breakthrough in energy storage capabilities for Lithium Ion batteries.
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If I read it correctly, they claim 400 watt-hours per kilogram

About 180 watt-hours per pound

One HP is about 750 watts

So about 4.1 pounds per HP

So if hours flight is 75 HP average in a RV-3

That's a 307 pound battery, with no allowance for electric motor losses and no safety margin before the batteries go dead. I wonder how the FAA will calculate the "remaining fuel" FAR?

It's getting there, but much better for a self-launching sailplane (which you can buy now) than a fun RV-3...:)

Are my calculations about right?
 
Not sure of the calculations but I think it important to think about the differences in power needs for propulsion in the different phases of flight. The real question is what level of power (HP) does an RV-3 need for cruise flight vs what it needs for climb? If it takes quite a bit of the energy to get the RV to climb to altitude how much will be left over for cruise flight? And how much of that power is actually needed for cruise flight? Does an RV-3 need 75 HP to maintain altitude and XXX cruise speed? It is my thoughts that this is one of the reasons why the motor glider community is leading the way for use of electric propulsion. These gliders most likely are not going to need the high HP requirements to get them to altitude. Then it is also obvious they do not need any of that HP for cruise. Their needs for energy are then limited to a specific flight phase.

The RV-3, although relatively slick, is not as aerodynamic as other long wingspan low aspect ratio airframes such as gliders. Therefore it will require more HP at cruise than an airplane that may have more wing and less drag.

It seems to me the short stubby wing of our RV's might not be the best platform for electric propulsion.
 
400 cycles!

First it would have to be practical in a car, before it would become economical in the marketplace and be available for your plane. The article claims the batteries "perform well after 400 cycles". If you drive your car to work and back 5 days a week that's 10 cycles per week, or 40 weeks, or a lot less than a year, even if you don't drive on the weekend. Who would spend that much money for a car that needs a major, high dollar, component replacement in less than a year?:eek:
 
az_gila said:
If I read it correctly, they claim 400 watt-hours per kilogram

About 180 watt-hours per pound

One HP is about 750 watts....
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Using your numbers and 160 hp at 65% power, with a 30 gallon tank. This gives me about 8.7 gph and about 3.5 hours at 104 hp. That's roughly 77,600 watts or 271,500 watt-hours of energy if my arithmetic is right.

At 180 watt-hours per pound, the battery equivalent to the 30 gallons of fuel will weigh very roughly 1,500 pounds. And that's without any mounting equipment, the motor or any other hardware or electronics.

To put it into perspective, the RV-3s built so far are running in the 695 to 890 pound range empty with their engines.

Dave
 
I think what we're really waiting for could be a lithium air battery. Nevereverwrong Wiki claims theoretical 12kwh/kg.
 
Just thinking

If batteries ever become that cheap or practical, then gas will become really cheap. Think about it, it is much easier to lower the price of gasoline to maintain market share (and profit) then to invest in battery technology. I think gas will always be cheaper than batteries, unless the tax man gets involved. JMHO. I would love to see batteries get cheaper, just to compete with OPEC.
My bet is we will see avgas made from natural gas before any battery technology gets too advance. i would stick with an "autogas" RV.

Reminds me of the movie Las Vegas Vacation, the guy sells his kidney because technology is advancing to fast and wanted to make sure he could still get top dollar.:D
 
bkthomps said:
ironic username given the post content
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Gasman = Propane............. Propane is currently less than $2.50 per gallon. Will a Lycoming run on propane??? Yes it will. Is it practical?....... No!

Over 100 octane and no fuel pump. Propane is 4.2 lbs. per gallon......:eek:
 
Lux Wrangler said:
First it would have to be practical in a car, before it would become economical in the marketplace and be available for your plane.
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Because there are hundreds of practical car engines that run on gas that have made their way into the aviation world, right? :rolleyes:

No, this revolution will have to start the same way all alternative engines do... With significant skepticism, derision, and ridicule from many pilots of Lycoming-powered aircraft. It's a sad but true fact that all of these options (automotive gas or electric) will initially be less practical than a Lycoming.
 
az_gila said:
Yes... and as I said on my calculations post - much better suited to a powered sailplane, even if used in consant "engine-on" mode rather than a sport RV-3..
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Gil, I understand what you are saying. But, I don't have a sailplane. I do have an Rv3 ready for a motor. I am looking for a one hour local flight. The RV3 is the cheapest and best built airframe on the market now. And with wing tip extensions, it will do just fine on low power.

I did not mean to imply that the electric motor will replace the Lycoming and perform the same. The RV3 only uses 38 Lycoming horse power to fly at a true airspeed of 100 stat. mph.

By exchanging the fuel/battery tanks and installing the Lycoming and motor mount and removing the wing tips, the three can be returned to stock form.
 
I think electric powered flight will become practical, but

Because there are hundreds of practical car engines that run on gas that have made their way into the aviation world, right? - Snowflake
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That's right. Airplanes have internal combustion, piston engines that run on gasoline, just like "hundreds of practical car engines".

No, this revolution will have to start the same way all alternative engines do... With significant skepticism, derision, and ridicule from many pilots of Lycoming-powered aircraft. It's a sad but true fact that all of these options (automotive gas or electric) will initially be less practical than a Lycoming. - Snowflake
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High performance cross country airplanes that need expensive battery replacement after 400 flights is a lot less practical.
 
400 cycles is still nothing

But that is not what this thread is about............ - Gasman
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OK, if you prefer, "an open cockpit 3 for local flights" that need expensive battery replacement after 400 flights is a lot less practical.
 
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