I've seen this phrase used to describe the Fokker DVII, and to explain its unique non-steep stall maneuver, but I've never heard a description of what it actually means. Can someone enlighten me?
I've seen this phrase used to describe the Fokker DVII, and to explain its unique non-steep stall maneuver, but I've never heard a description of what it actually means. Can someone enlighten me?
Ever been to an air show and watched an acrobatic pilot take his plane into a vertical climb and stop, then slowly move downward, tail first? These aircraft have a combination of horsepower and rudder and elevator authority to maintain controlled flight in high alpha situations. The d.vii would seem to have an early version of that ability, to a lesser extent, but more than its contemporaries.
what he said! ive read reference to propeller hanging fokkers in a few ww1 memoirs. i didnt really have anything much to add to the thread, i just felt obligated to post in a thread about fokker DVIIs since its my favorite ww1 a/c!!!!
You can see a good example of propeller hanging about 3 minutes into this video. https://www.youtube.com/watch?v=R_EMX7N9PjA
There are many examples of RC planes prop-hanging available on Youtube but less with real planes.
I have never found any modern evaluation of the flight character of the d.vii which would be an interesting read ( here is such an example: http://thevintageaviator.co.nz/proje...es-flying-d-va ). Modern aircraft designed to do these stunts are set up such that even at low or zero airspeed there is enough prop induced air moving across the tail surface that those controls remain effective. From Wikipedia:
"Manfred von Richthofen flew the V 11 and found it tricky, unpleasant, and directionally unstable in a dive. In response to these complaints, Reinhold Platz lengthened the rear fuselage by one structural bay, and added a triangular vertical fin in front of the rudder. Upon flying the modified V 11, Richthofen praised it as the best aircraft of the competition. It offered excellent performance from the outdated Mercedes engine, yet was safe and easy to fly" I wonder if that lengthening had the effect of keeping some of that prop induced air moving over the tail surfaces at full power, and I suspect the rudder was quite effective leading to some of the stability comments of the v11 prototype?
Last edited by BB401; 08-27-2016 at 04:40.
And for d.vii nerds like me, there's no substitute for staring slack-jawed at the real thing: http://www.williammaloney.com/Aviati.../05Cockpit.htm
Man that cockpit is small
Great pics, Bob.
Thanks guys, this is making more sense. I figured the effect is that the plane moves more slowly somehow, I just couldn't understand how it was done without cutting the engine or going at least somewhat vertical and reducing speed that way. I found some more discussion about it on the Rise of Flight game forum on this thread. It sounds like 'hanging on the prop' involves a high 'angle of attack' which someone on that site defined as:
"Angle of Attack (AOA) is the angle between the aircraft chordline (the line drawn from the trailing edge to the leading edge of the wing) and the flight path of the airplane through the air."
So if I understand it right, basically the nose of the plane is 'up' (or down I suppose) relative to the direction the plane is actually moving, causing more wind resistance and slowing the plane down. I might not be using the correct terms to describe it but I think I see how it works now.
EDIT: That said, I still think the phrase 'hanging on its prop' is confusing.
I was at the Old Rhinebeck Aerodrome last weekend and when the Fokker DVII flew it did just that. It hung on it's prop for quite a few seconds before he had to level off. It was quite exciting to see the real deal in action.
Did you take any photographs of it, Peter, please?
Another thing which the DVII benefitted from was its clean design and few bracing wires. The wires were a source of additional drag on nearly every aircraft. Without the wires the DVII has a lower stall speed and - at least in part - the ability to prop hang. I seem to recall reading somewhere that the DVII stalled at 25 or 27 mph. That seems unusually low. Typical WW1 stall speeds were around 40/50 mph.
Another benefit may have come from the thick wing profile. Both the Dr1 and the DVII were derided war-time for their thick wing profiles but subsequently their wings were found to be quite efficient.
Further to the above:
A modern 80% repro of a DVII stalls at 34mph or 30 knots on a slightly lower wing loading than its WW1 ancestors.
https://en.wikipedia.org/wiki/Airdrome_Fokker_D-VII
I believe I saw a Piper Cub do the same thing at an airshow years ago.
Another aircraft with a very low stall speed of 33 knots (38 mph).
Bookmarks