Could the speed of sound be broken with electric AC ?

[CubersWrist]

Re: Could the speed of sound be broken with electric AC ?

Not that I know of.

[Race5]

Re: Could the speed of sound be broken with electric AC ?

Has there ever been a flying wing type of air racer ?

Flying wing do not lend themselves to the low altitudes and high angle of attack / high G turns that are required for air racing.

[Colbourne]

Re: Could the speed of sound be broken with electric AC ?

All I can think of when reading this topic is this -



Rich

As a child I really enjoyed playing with round the pole electrics. I was using really cheap 3V motors (Mabuchi RE-280SA-2865 I think )(30cents each) and put about 48V down the lines. Cooling holes I cut in the case really helped preserve the brushes. I totally blew away the competition who were using $20 motors when I turned up at model exhibition where they were flying. My speed models ended up with wings cut from ice cream containers and a spruce fuselage.
It was also a way to give life to the built up construction scale models originally designed for rubber power.
I would like to go back and try with brushless motors where the motors can survive much longer.

[Colbourne]

Re: Could the speed of sound be broken with electric AC ?

https://www.nasa.gov/centers/armstrong/news/FactSheets/FS-068-DFRC.html

This solar powered aircraft with 14 electric motors ( 2hp each) is able to fly at 170mph at altitude.

https://en.wikipedia.org/wiki/Qinetiq_Zephyr

The Zephyr uses 2 electric motors of 0.6 hp each and is able to fly at over 200mph at altitude.

[Colbourne]

Re: Could the speed of sound be broken with electric AC ?

Just saw your more in depth explanation. I retract the laugh. Sorry, been working for years to break 400 at Reno, and I forgot that you had specified at higher altitudes. It is a good point that electric motors don't need oxygen to breath/work, which Ben Rich said was a big design point on the U-2.

So if you're going to build an all-out record breaking speed machine, then I say anything is possible with $$$. With all the complexity with the size and solar panels and detaching components, I don't see the next generation of airliner, but I do see a technology demonstrator or a speed record setter. Not sure what the rules are on breaking records, but with all the complexity this would take, it sounds simpler if you could get a tow/ride closer to altitude.

I do believe an electric aircraft could reach 500mph at Reno's altitude, although for how long will depend on the state of battery technology. Imagine an aircraft similar to the Mustang built of carbon fibre with improved aerodynamics. Similar flying weight but 80% of that being batteries. 4000kW motor. The Mustang has a weight of about 4000kg , so that would be a battery of about 3200kg. Batteries are currently around 250 Wh/kg so this equates to about 12minutes of full power usage. (if my off the cuff calculations are correct).
What is the flying weight of Strega and its hp ?

https://theconversation.com/teslas-batteries-have-reached-their-limit-heres-how-they-could-go-further-64765

"Bosch’s battery company, Seeo, claims to have developed prototype batteries with an energy density of 350 Wh/kg (watt-hour per kilogram). In comparison, the Panasonic 18650 cells that Tesla uses have an energy density of just 254 Wh/kg. "

"Two potential alternatives are sodium ion-based and possibly sodium metal-based batteries, which have higher energy densities than lithium ion batteries. One such prototype battery has demonstrated 650Wh/kg of energy density,"

[Jukka]

Re: Could the speed of sound be broken with electric AC ?

Flying wing do not lend themselves to the low altitudes and high angle of attack / high G turns that are required for air racing.

Look cool though; https://www.youtube.com/watch?v=6pBxqUG4cfk

[Colbourne]

Re: Could the speed of sound be broken with electric AC ?

Look cool though; https://www.youtube.com/watch?v=6pBxqUG4cfk

https://en.wikipedia.org/wiki/Miller-Bohannon_JM-2_Pushy_Galore

Bohannan entered the aircraft in the Reno Air Races in 1994, qualifying in third place in the Formula One class, with a speed of 236.153 mph (380.051 km/h).[1]

In 1995 Bohannan flew the aircraft to second place in the Formula One Gold championship race at Reno, Nevada.[1]

[Jukka]

Re: Could the speed of sound be broken with electric AC ?

Late Paul McCready developed fully solar power airplanes....with 10% efficienct panels.

Now they have 3 x the efficiency.

https://en.wikipedia.org/wiki/MacCready_Solar_Challenger

Are we missing something ?

[Jukka]

Re: Could the speed of sound be broken with electric AC ?

Delta DYKE is a flying wing.

https://www.youtube.com/watch?v=5imyOLhIJDQ

[Jukka]

Re: Could the speed of sound be broken with electric AC ?

NASA is researching the flying wing. Also the blended wing is coming.

Here Albion Bowers and the Mars conquering flying wing; https://www.youtube.com/watch?v=w-dk1NpVNNI

I still wonder how come the flying wing hasn't taken the scene yet.

I think there is an answer. Something hasn't been discovered yet.

It must relate to stability at different flight patterns.

[CubersWrist]

Re: Could the speed of sound be broken with electric AC ?

FPVWRA (wing racing association) is all wings. I raced in Spec class this year and it was a lot of fun at 70mph. The Sport class gets up to 120mph. I think the wings are used because the foam is really easy to cut and build and it's easy to put the prop in the back so the propeller doesn't puncture the inflatable pylons.

I did talk to one of the guys spearheading the BSLD (bell shaped lift distribution) for wings and he said there are very particular conditions where wings are better than standard aircraft, and he didn't think racing was one.

[Jukka]

Re: Could the speed of sound be broken with electric AC ?

FPVWRA (wing racing association) is all wings. I raced in Spec class this year and it was a lot of fun at 70mph. The Sport class gets up to 120mph. I think the wings are used because the foam is really easy to cut and build and it's easy to put the prop in the back so the propeller doesn't puncture the inflatable pylons.

I did talk to one of the guys spearheading the BSLD (bell shaped lift distribution) for wings and he said there are very particular conditions where wings are better than standard aircraft, and he didn't think racing was one.

Looks interesting; https://www.youtube.com/watch?v=bq41na-yhsE

[Jukka]

Re: Could the speed of sound be broken with electric AC ?

How about this...420 km/h on electric.

https://www.youtube.com/watch?v=IQlnZkxKEmU

[Jukka]

Re: Could the speed of sound be broken with electric AC ?

Delta wing is clean.

Here Avro Vulcan B1: https://www.youtube.com/watch?v=nTEvT-SV6Y0

Here B2:https://www.youtube.com/watch?v=UkWO5zVPz4g

[Jukka]

Re: Could the speed of sound be broken with electric AC ?

Sorry C2 and original in films; https://upload.wikimedia.org/wikiped..._Planforms.jpg