Electric Pusher prop?

[Thalass]

You could try a slot around the back corners of the car (top and possibly sides) where the air is squeezed out at high speed, with the intake wherever, at the front grille, perhaps. Rather than a few big round ones.
They've tried that sort of thing on aircraft wings to keep the air energised and laminar at low speeds/high AoGs, but it wasn't really worth it as far as lift went.

Of course it may not be worth the extra energy and weight.

[aerohead]

A few thoughts: the prop on the RC car is in relatively "clean" air,whereas behind the van/suv,it would be in the lee of the vehicle,with only the turbulent wake as a source of air.That means the prop would have to induce air from behind itself,forward around the outside of the disc area.Then the air would be blasted rearward through the prop,setting up a circulation of sorts(like a helicopter in ground-effect,only sideways)making it difficult to induce the air forward again,to re-circulate through the prop.Unlike a suction slot,the prop would have no boundary layer effect,and a dubious amount of thrust if any,only stalled,in a region of recirculating air within the wake.--------------------------------- Also,to get 10-hp of thrust would require about 12.5-Bhp at the shaft (very inefficient).-------------------------------- Finally,as others have touched on,the safety ramifications,should some unfortunate motorist or cyclist rearend the prop,is too grim to even contemplate.

[Xringer]

Originally Posted by BBsGarage

your also adding an abundance of weight that also needs to be pushed.
interesting idea though.

If I were to drive the wheels with a hybrid conversion kit, I would still
be adding weight.

Add weight to gain the short term advantage of gaining some MPG
by using power that came off the grid the night before..

When you build a full EV, you gain all kinds of weight and shorten your
range for the advantage of not making trips to the gas station.
It's a trade off.

If you converted your car into a Weak plug-in hybrid, you gain FE
for the short haul only. Once you start heading across the state,
you run down your pack and end up using extra fuel to carry it..

If you could afford very light batteries, your over-all FE could
be a lot better.

[Xringer]

Originally Posted by aerohead

A few thoughts: the prop on the RC car is in relatively "clean" air,whereas behind the van/suv,it would be in the lee of the vehicle,with only the turbulent wake as a source of air.That means the prop would have to induce air from behind itself,forward around the outside of the disc area.Then the air would be blasted rearward through the prop,setting up a circulation of sorts(like a helicopter in ground-effect,only sideways)making it difficult to induce the air forward again,to re-circulate through the prop.Unlike a suction slot,the prop would have no boundary layer effect,and a dubious amount of thrust if any,only stalled,in a region of recirculating air within the wake.--------------------------------- Also,to get 10-hp of thrust would require about 12.5-Bhp at the shaft (very inefficient).-------------------------------- Finally,as others have touched on,the safety ramifications,should some unfortunate motorist or cyclist rearend the prop,is too grim to even contemplate.

Yeah, forget the prop. I've seen too many RC airplane accidents to think
a large prop is anywhere near safe.

BUT, a ducted fan might be usable. A good one might develop some pretty good thrust. EDFs have the advantage of shorter blades (impellers), thus lower RPM & tip speeds. Big props & big HP get tips speeds up near mach1.. Not good.


Now that I have the coro spoiler and wake boards installed, I did some yarn testing back there.
There is almost zero turbulence on top of the spare tire and across the rear glass..


Where did it go??

[Cd]

http://images.lowes.com/product/026715/026715153336.jpg


I've wondered about something like that for years.
Daydreaming of something like this,I wanted to buy one of these and run it from my cigarette lighter. I planned to relocate my plate and attach the blower in its place.

Then I thought .... WHY ?

I don't have the link right in front of me, but something like this has been used to great effect in semis using a compressed air system that channels air into a tighter wake.

( If you are really interested, I can try and find it )

[trikkonceptz]

Originally Posted by Xringer

If the impeller housing was made out of heavy gauge stuff, they would be safe enough.

Maybe use 4 of these motors..?.
Battery Powered Systems

I had always thought of building two of these to sit inside the vehicle, where the back seat use to be and ducted from the rear doors to draw the air in. I had always wanted air to help push the car at hwy speeds in order to reduce engine LOD. Nice to see it is not impossible ..

[Daox]

IMO this wouldn't be a good idea at all. No offense intended. It is a neat and fun idea. My reasoning is, the prop is not going to give you an equal amount of thrust per amount of energy spent that an electric motor is going to give coupled to your tranny. Thus you have one more loss of efficiency and a less efficient system overall.

[mwpiper]

What if, I had a 3' pusher prop mounted in the center of the rear hatch?
And once I got out on the highway, I turned on about 10 HP of thrust?

Have you seen the cars/trucks with the little propeller stuck in the hitch receiver? You would have that but bigger.

Propellers are sensitive to incoming air direction. You would find such an arrangement would produce little or no thrust. But it would consume power thrashing in the air. Biggest advantage would be a deterrent to tailgaters.

The answer is....no. Just....no.

[Xringer]

Okay guys! Let's forget I ever mentioned the word "Propeller" and assume that
B. F. Ponder was an early scammer..
http://blog.modernmechanix.com/mags/...4/prop_car.jpg
And this car never really got over 25 MPH..

----

What about using a Ducted Fan ? (As shown above, but bigger).

If you could make one that delivered 300 pounds of thrust, using 200 pounds
of hardware and batteries..?.

The idea here is to somehow get power off the grid to help propel your car,
without performing major surgery on it..