If there were an unlimited slowest speed contest...

[jay flay tway]

Here's a question for the experts or for anyone to take a stab at:

If there were a slowest flying speed (absolute speed, not scale speed) contest with NO limits whatsoever, (other than no lighter-than-air, and no prop hanging) what kind of plane would win it?? It would only have to fly from point A to B (same height), say 50 feet indoors in still air.

type of power?
how big?
etc., etc.


Here's my guess...

A very big--about 8-foot span--plane with an intricate built-up two-surface, undercambered wing, using a lot of carbon-fiber-covered hollow balsa.
Rubber powered (no radio is required so rubber might be lightest) with a pusher prop (aren't they more efficient?) so maybe a canard.
maybe a biplane with lots of vertical separation between the wings and the prop between the wings to avoid the inefficiency of propwash.


Or would it be something quite small??

[Sparky Paul]

Micro-film covered rubber powered planes are the slowest fliers I've seen.
Something large with that style of structure and covering would be a starting point.

[Salto]

If no prop hanging is allowed, then it has to be a glider. All powered planes at high angles of attack (slow speed) will obtain some advantage from thrust vectored upwards, and will therefore break your "no prop hanging" rule to a greater or lesser degree.

Graham.

[jay flay tway]

Salto,
Yeah, i wondered about that. It's a gray area. Not sure how that would be limited.
Maybe gliders and only 5 feet of vertical difference between the starting point and the finishing point and flying straight down a corridor to not allow circling.

[noodle]

Salto, slow speed does not neccessarily mean high thrust angles. An airplane designed to go as slow as possible would simply have the wing placed at a high AOA, not the motor.

noodle

[Andy W]

Research rubber powered duration models.

[markdrela]

In modeldom, indoor rubber models have the lowest wing loadings, and hence the lowest flight speeds. A modern F1D model has a 0.055 oz/ft^2 loading, and flies at about 0.7 m/s. That's about 1% of the wing loading and 10% of the flight speed of a typical light RC glider.

[Salto]

Salto, slow speed does not neccessarily mean high thrust angles. An airplane designed to go as slow as possible would simply have the wing placed at a high AOA, not the motor.

noodle

Yes, I considered that, but if it's a tractor the prop blast will hit the wing and deflect downwards, thus gaining some "lift" from the prop. And if it's a pusher the prop will likely be in the wing's downdraft and be similarly effected.

I was simply making the point that it would be difficult to eliminate the effects of a prop in the vertical plane.

Graham.

[stu78]

Just to stir things up a little...

What about a helicopter? They can fly really slow (about 0 is the slowest i think :))

I did think it might break your "no prop hanging" rule, but it is a rotory WING, not a propeller that it is hanging on.

Stuart

[jay flay tway]

I just thought of a way to eliminate the ambiguity of "when prop hanging begins" (btw, prop, rotor, whatever). It would allow helicopters too.

The average speed of the prop blades is factored in somehow into the contest. The heli may be able to fly very slowly but the blades would need to move fast so helis would be noncompetitive, prop hanging too, because both are less efficient.
I'm not sure what the mathematical factor might have to be but maybe the avg. prop speed can't exceed half of the aircraft's speed or something like that.

Problem though. Very difficult to measure. I guess a stroboscobe could be used.

[HELModels]

Competition planes usually take on a certain look peculiar to the category because form will follow function. Define the function better and unwanted forms will be eliminated.

[Bill Mixon]

Something with low wing loading as mentioned.
Like this..
http://www.rcgroups.com/forums/showthread.php?t=389338