How slow can you go?

[Tony]

Must be fake......

 

[adam_r]

nope. . very light air frame and huge wings will allow you to do that

[andyelcomb]

Stiff nose wind will help massively too. If its windy enough you don't need any ground speed at all.

[Tony]

Looks so odd landing without speed, that's why i thought it was CGI.

[liner33]

yep its the windspeed over the wings rather than the speed of the plane that gives lift

 

Plane on conveyor belt anyone??

[Sagitar]

yep its the windspeed over the wings rather than the speed of the plane that gives lift

 

Plane on conveyor belt anyone??

I think we have been there before.

 

Tony if you google aerofoil design for STOL you will find interesting stuff.

 

Planes built to land in these difficult conditions have different aerofoils than "normal" planes and use leading and trailing flaps to prevent the airflow from separating from the wing at high angles of attack. This lowers the speed at which the wing stalls and delivers lift at much lower speeds than usual.

 

There are practical difficulties in that the surface of the strips on which landings are made are often very poor, so the wing structures need to be stronger than usual and thick wings help. The clearance widthwise can be a problem too so you don't want wings that are very long. STOL wings tend therefore to be a bit stubby, but with a wide chord (to give a large lifting surface) and a thick aerofoil. They also use wing tip devices to stop air from spilling off the end of the wing.

[Tony]

Thanks...... It's the slowest landing i've seen without the use of rockets.

[Tango]

Air speed is unrelated to an aircrafts forward progress as observed from the ground. An aircraft with a stalling speed of say 40 knots would appear almost stationary to the ground when flying near stall speed in a headwind of 40 knots. Turn around and fly downwind in the same conditions and speed in relation to the ground would be 80 knots, except you probably stall out and head for the ground in the turn.

Fly in headwinds exceeding stalling speed and in theory you could fly and land whilst moving backwards, but I've only ever seen it performed with R/C models with a very light wing loading.

 

We were flying a few weeks ago in head winds gusting to 40 knots and gliders on winch tow were leaving the ground with hardly any ground run at all.

[GamithUK]

Case in point - strong headwinds means this Piper cub is flying backwards:

 

And here's another aircraft flying sideways:

https://www.youtube.com/watch?feature=player_detailpage&v=9gfGZwRDPRM

 

 

[Sagitar]

There is some other coverage of the event at which the OP video was taken here 

 

The aircraft involved would certainly be helped by a head wind, but they don't depend upon it. They fly very slowly and with a high rate of climb or descent, because they are designed to do that, even in still air.

 

I guess the aircraft in the competition are specially prepared, but even a work-horse STOL aircraft such as the Scottish Aviation Pioneer, that would carry a pilot and four passengers, had a stalling speed of only 38 m.p.h.

[Tango]

Quite a few of those were much modified Piper Cubs. Without modification the original Cub had a stalling speed of only 38 mph (33 knots), which is similar to the WW2 Fieseler Fi 156 Storch.

Looking at that footage, modifications have been made to further lighten the airframe, change the flap configuration and add slats to further reduce the stall speed.

 

Another major consideration is the propellor, which is basically a rotating wing. In a high angle of attack the prop generates lift and the backwash provides additional lift to the mainplane which, as you can see in the footage, allows at least one aircraft to almost hang on the prop with minimal forward motion.  

[Tony]

You know what i posted the video as a simple curiosity but the backwash of solid information has opened a completely different mind frame in aerodynamics that has belayed my cocky title for the thread. 

 

As a simple spectator to the aviation world i'm at ore to the knowledge within this realm at wim central. Absorbing this information and watching the video again....and again i can see the deliberate changes in the aircraft/ speed/ wind direction and ground effect.....