Discussion in 'General Experimental Aviation Questions' started by looseround, Sep 24, 2005.
-UL-39 ALBI =V max=340 km/h ... \V min=65 km/h !\
Don't want to detract from the current thread but the Beachner V8 would be a good thread of its own and hopefully could be a design that is resurrected someday.
There was one.....http://www.homebuiltairplanes.com/f...sion-discussion/1321-beachner-v8-special.html
Where did you find that Henryk?
Looks like some sort of ornithopter. Unbelievable workmanship and design.
=extremal france construction!
(not flying,I think...)
=4-wing Toporovs GIORDANO ,muscle powered fly !
=Toporovs ISTINA, 28HP, circa 100 kG thrust force...
OK, now I'm dying to know more about this dragonfly thing. Is there a name? History? Designer or group?
-soething moore...René RIOUT
Resurrecting this thread, as I recall being fascinated with this back in the 80s...
I recently saw a news article about the Bye Aviation eFlyer electric aircraft: https://byeaerospace.com/eflyer/
and the Pipistrel Alpha Electro: https://www.pipistrel-usa.com/alpha-electro/
I also read a news article about a Texas firm that has developed a powerful new electric turbine motor that significantly increases torque and power output. https://newatlas.com/linear-labs-hunstable-electric-motor/60974/
Given the development of aircraft that use electric technology, and the increases in battery technology, coupled with this new motor development, why couldn't a ducted fan/shrouded prop powerplant be developed for use in something like the JetHawk? Add in carbon fiber construction, with high-strength, lighter weight, and we might well be onto something. I'm envisioning something in shape similar to the RANS S-11 Pursuit with a LongEZ type wing...
Just a few thoughts.
Oh, and @bikeface, if you're still out there, and still have the plans/info on the JetHawk II, I'd like to ask if you could PM me please.
Look around this site. You will find a single engine twin ducted fan fighter look alike in Russia. Search for Malish.
Also search for electric aircraft, and read why it can and why it can’t to your heart’s content. Short answer; batteries don’t yet have enough energy per pound to be very useful.
Welcome to HBA.
Thank you for the welcome.
I beg to differ re: batteries don't have enough energy per pound. Both Bye and Pipistrel have flying aircraft that have demonstrated up to two hours endurance at 90-100hp. Bye has sold hundreds of the aircraft already, and the certification is still underway. Pipistrels are flying all over Europe, with nearly a dozen in the US.
And battery tech is improving nearly exponentially. So even if what you claim is true, and I find it rather pessimistic, it is only a matter of a couple of years before even that limitation ceases to be a matter of concern, if that long.
Coupled with the Texas motor, and it's increased torque, power, and efficiency, I would prefer to think it's more possible, than to think it's impossible.
You are welcome.
How many airplanes has Bye delivered?
The Pipistrel looks promising. But it, too, has limitations, including battery life.
Yes, battery technology is improving; note that I wrote “don’t yet have”. But they are not yet to the point of being useful for most of us. Pessimistic? No. Realistic. Even if there were a big break-through in storage density today, batteries would not be reasonably available to homebuilders in “a couple of years.”. Note the difficulty that Tesla has had trying to ramp up production of (current technology) batteries, even with waiting customers.
So build one.
Hopefully without giving offense, I'm rather put off by your tone. Bye has two or three aircraft already flying, and as I said clearly, without stuttering or misspelling anything, they are currently undergoing the certification process with the FAA. One would hope that someone as knowledgeable as you would understand what that meant. Stop moving the goalposts.
Bye has contracted with BlackBird to purchase 100 aircraft, to be certified as commuters, and has also accepted a purchase deposit from OSM Aviation Group for 60 aircraft, to be used as trainers.
And for the record, according to the manufacturer, Pipistrel already has over a dozen electric aircraft sold, delivered, and flying in the US. As of July 2019, Pipistrel has signed an agreement to deliver 50 aircraft to the US Aeroclub, and has also been selected by the USAF to provide eleven aircraft to the Character-Education Solo Flight Program. Pipistrel is also developing a motor system for sale as a separate propulsion package for aircraft in the 60kw (80hp) range.
So please don't act like these aircraft are still only just on the drawing board. They are already flying.
Notice that I also never claimed any of this technology was available immediately off-the-shelf, and cheap enough for the average Joe to get from Wicks or Trade-a-Plane, even though Pipistrel is developing the package I just mentioned. I merely said that it was interesting, and would make a good line of thinking for those who knew more about these things. Since it came up in the thread that a standard combustion engine would take up too much room in the body of the aircraft and restrict airflow, I thought it might not be a bad idea to substitute a much smaller, lighter electric motor that would not take up too much room and restrict airflow. That weight would seem to me to be better to be taken up by batteries, replacing the weight of the engine, fuel, oil, and associated equipment. And the batteries don't have to be co-located in one place as does a fuel tank. They can be spread out all over the airframe, and act as weight distribution if needed.
However, there is also the recent (July 3, 2019) article regarding Oxis Energy's development and upcoming delivery of proof-of-concept, advanced lightweight lithium-sulfur cells to Bye Aerospace. These batteries are reported to deliver up to 160% more storage capacity at 80% of the weight of the standard lithium-oxide batteries currently being used. Therefore, if the Bye and Pipistrel have X amount of electrical storage from Y amount of weight, then they can increase their storage with the same amount of weight. So the technology is there.
Again, I prefer to be more optimistic, thinking that someone out there can and will do it, rather than continually coming up with reasons why no one should bother.
Again, hopefully, without giving offense, I found your off-hand comment "So build one." to be patronizing, belittling, and rather insulting. I expected better, more positive and encouraging commentary from experienced and knowledgeable posters. I also note that no one else has been told "So build one" quite so disdainfully and dismissively as I was.
And now that I've been definitively told that I'm really not welcome in this thread, (and possibly on the entire board) you may feel free to flame away without fear of me bothering to read or being troubled to reply.
The Pipstrel Alpha Electro has an endurance of "up to 60 minutes (plus reserve)", as per their website: https://www.pipistrel-usa.com/alpha-electro/#technical_data
Bye just announced flight testing of its prototype last month. They still have to obtain certification. They have deposits for a few hundred aircraft, but they haven't actually sold any or made anything except a prototype. They also fail to mention range or endurance on their website. They're using the same Lithium-ion batteries with a energy density of 260Wh/kg everyone else (Pipstrel, Tesla, etc) is, so it's unlikely they will have much different range without a vastly heavier aircraft.
Battery are an industrial technology, and industrial technologies usually improve at a rate of 3-5% per year, the same as batteries have for the last 60 years. There has not been a significant increase or variance from this at any point. In 1960, commonly available battery density was 50 Wh/kg, at a 3% increase per year, it should be at 286 Wh/kg, but we're actually at 260 or so for lithium ion. There's nothing exponential about battery capacity growth.
There have been announcements of new battery technology that will change everything regularly for decades now, but nothing that has reached production. It will be 15-25 years before batteries will equal the energy density of gasoline, and still about 10 years out for a small plane with a 3 hour endurance.
It's not impossible, but it is impossible on the timescale you wish. I wish it weren't the case, but it's going to take time, there aren't any shortcuts.
Certainly electric aircraft are available today, and for certain limited mission requirements, they may make sense. But they are far inferior to combustion engines in range and refuel/recharge time, and will be for many years. Outside those limited missions, they don't make sense.
Note that a perfectly valid mission for otherwise impractical aircraft is "because I think it's cool," as long as the owner is honest with himself about it.
2hrs at 90hp is a 1,500lb battery.
Battery are stated to be improving at 5% a year and that is likely in the lab, but in production and affordable? In the light plane speed range a prop is more efficient than a ducted fan. The available electric motors are already over 90% efficient so not much room for improvements there. Power to weight improvements can allow a few more batteries to be carried. A reminder, electricity is not free nor pollution free at this time and into the foreseeable future.
Electric is practical now for self launching sailplanes and short duration sport and training aircraft. The usefulness will increase over time. There are also interesting hybrid possibilities while we wait for batteries to get "good enough. First electric flight was in the late 1800's in an airship.
Saunders Jethawk project inspired me to start my own project - ducted fan aircraft PJ-II "Dreamer"
I think you misspelled "incrementally."
Separate names with a comma.