Proairsport. New ultra light glider/airplane

On Thu, 19 Mar 2015 07:22:27 -0700, Bruce Hoult wrote:

Why, other than the weight of the electric motor and battery?

Wheelspin around the liftoff speed would kill acceleration and may
lengthen the takeoff run, especially on wet grass.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

At 14:38 19 March 2015, Martin Gregorie wrote:
On Thu, 19 Mar 2015 07:22:27 -0700, Bruce Hoult wrote:

Why, other than the weight of the electric motor and battery?

Wheelspin around the liftoff speed would kill acceleration and may
lengthen the takeoff run, especially on wet grass.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |


The aircraft sits on its mainwheels and nosewheel - the wing has a negative
angle of attack, no lift produced. Throughout the acceleration this
condition is maintained, until rotation speed is reached.

Independence, Operational Convenience, Simplicity, Lower Cost.

Questions to me via website.

R

On Thursday, March 19, 2015 at 12:00:08 PM UTC-5, Roger Hurley wrote:

The aircraft sits on its mainwheels and nosewheel - the wing has a negative
angle of attack, no lift produced. Throughout the acceleration this
condition is maintained, until rotation speed is reached.

Independence, Operational Convenience, Simplicity, Lower Cost.

Questions to me via website.

Actually, Roger, I really like the idea of drive wheels for acceleration. Maybe because I had the same thought for being able to self launch a very light sailplane from a ridge site 25+ years ago. At the time, my thought was for a simple 12 volt battery (like most sailplanes have) to drive a model airplane electric starter motor, belt driving the wheel on the glider. Never was too keen on the idea of trying to launch in light wind, running while carrying and controling a flying machine.

Hope you weren't offended by my "burnout" comment. Looks like you are working to resolve the issues that we all face. Now, if we can get the production volume up on the jets to get the cost down...

Steve Leonard

Interesting concept - wondering how many takeoffs are planned per battery charge?

And unless the tires (tyres?) are a bit wider, it might have trouble at some of the rougher grass fields I've flown from.

But a more important question: What does GloW mean? C'mon, guys, if you use a cute acronym (and you Brits are worse than us 'Muricans - QinetiQ, really?) at least explain how it was derived!

Kirk

The electric powered wheel is such a bad idea that Airbus has been testing it on airliners. Using it for taxi and acceleration during take off reduces fuel consumption considerably and shortens takeoff distance. Newer electric motors can produce tremendous amounts of torque and are much lighter. Just what you need for initial acceleration.

Current self launchers are many times equipped with finicky engines and complicated mechanics to expose the prop. When you need the lowest sink rate to prevent a land out, deploying the motor decreases the glider's performance to it's lowest.

If our sport is to survive, we need innovation. A low maintenance, affordable self launch could go a long way toward that goal.

Charlie

At 09:40 20 March 2015, wrote:
The electric powered wheel is such a bad idea that Airbus has been
testing
=
it on airliners. Using it for taxi and acceleration during take off
reduces=
fuel consumption considerably and shortens takeoff distance. Newer
electri=
c motors can produce tremendous amounts of torque and are much lighter.
Jus=
t what you need for initial acceleration.=20

Current self launchers are many times equipped with finicky engines and
com=
plicated mechanics to expose the prop. When you need the lowest sink rate
t=
o prevent a land out, deploying the motor decreases the glider's
performanc=
e to it's lowest.

If our sport is to survive, we need innovation. A low maintenance,
affordab=
le self launch could go a long way toward that goal.=20

Charlie

Launch price now on the website www.proairsport.com - hit the Priority
Price button or go to Contact/Order in the menus.

We think this fits with the themes in Charlie's last para.

Roger

Neat, but what I wanna know is if I can use the electric motor to spin the wheels up before landing so I don't have to hear that screech and smell burning rubber when touching down on asphalt runways;-)

Seriously though, I'm wondering if they're keeping the electric motor light by relying on the fact that it will be used only for short bursts with long periods of rest. Sort of like a starter motor, it seems to me they could get the power they need in a lighter motor by running it at much higher than it's rated continuous output because it will do so only for a short time and then have a long cool odd period.