On Tuesday, February 17, 2009 at 9:49:01 AM UTC, Rob Arndt wrote:
On Feb 17, 1:29�am, Rob Arndt <teuton...@aol.com> wrote:
On Feb 17, 12:34 am, Gordon <Gor...@oldboldpilots.org> wrote:
On Feb 17, 1:46 am, Gordon <Gor...@oldboldpilots.org> wrote:
The other thing in the pack of photos is a small German scout helicopter found and tested by the Allies postwar. It is quite well finished with a closable cockpit enclosure and an interesting tail
prop between its twin tail booms - the a/c type is painted in large block letters as "WN 342" with a title "DOBLHOFF" (spelling verified) painted directly below on the single vertical tail. This odd vertical tail is mounted at the mid-point of the horizontal stab that connects the twin tail booms. After cockpit entry, the windshield and forward cockpit cover hinged back to provide a modest wind break for the pilot and single passenger. Looks like the pilot has shoulder straps and
the pax does not. Overall, a very interesting configuration. The
most intriguing aspect is the jet exhausts that come from the ends of the backwards-swept rotor blades.
After remembering that GIMF, I found cites that confirm this
particular aircraft is Doblhoff's WNF 342 V-4, the airframe currently held in the Smithsonian in an unrestored state. (http://tanks45.tripod.com/Jets45/Histories/Doblhoff/
Doblhoff.htm )
A gent with the handle, "Never Was An Arrow" posted this quote: "WHF 342 V4 was the helicopter that American forces found in Zeleem in Southern Austria. It was a von Doblhoff creation. His team drove many miles through the country, away from the Russians, to get their prize into American hands. It was tied down to a flatbed truck and had 25 hours airtime. It drove compressed air into the blade reactor system for hovering AND powered the helicopter's fixed pitch propeller for forward flight.
Another cite: "Another Austrian, named Friedrich von Doblhoff, also developed the first successful "tipjet" helicopter, the "WNF-342". In this scheme, the rotor has some type of jet unit at the tips to cause rotation. Since the rotor turns itself, this eliminates the need to cancel torque. Von Doblhoff's designs used a piston engine to compress air, which was pumped to the rotor tips through pipes, and then mixed with fuel in a small combustion chamber in the rotor tips to create a fast gas jet. The rotor was only driven for takeoff and landings. The machine had a pusher propeller and flew like an autogyro in normal flight. Von Doblhoff built four prototypes between 1942 and 1945, the last of them having a weight of 640 kilograms (1,410 pounds), a rotor diameter of 9.9 meters (32 feet 6 inches), and an Argus As-411 engine with 135 horsepower. His machines never went into production, and in fact no tipjet helicopter ever has, though the tipjet concept has been revisited many times in different forms, it has never been used in any full-production helicopter design. "
http://www.youtube.com/watch?v=GF9R9Zq6P9M- shows the V-4 from
approximately 24 seconds into the video.
Rather stupid to not include a description of the four images - they
are each printed on half sheets of photo paper but the paper varies by thickness, like the printer used any available paper without regard
for matching. The images vary in size with a lot of wasted space
around the borders. I wish I could have afforded them all - the
photos I purchased were only labeled 26, 27, 28, & 30. I know I
missed at least a couple, including a highly detailed side view.
These were taken at the wind tunnel when the aircraft was in front of
the facility and then inside. The first is a 3/4rd rear view of the
sleek craft, showing the entire configuration. The jet-tip rotor
system and the pusher prop are shown well. Parked in front of open
bay. Second photo is a close-up of the interior, focused on the
pilot's controlls and instrument panel. In this photo, which looks forward from approximately the position directly behind the pilot to
his left shoulder, the flip-front cockpit cover reveals good modeler's details Third photo is oriented facing the nose of the aircraft on
the passenger side. This view shows the folding mechanism for the intricate rotor system and the attachments for the landing gear. US
Army car in the background. Last photo in the set shows a closeup of
the pusher prop unit after the airframe was placed in the wind
tunnel.
Lots of detail in the photos - Bob, do you want to post them on Coastcomp?
v/r Gordon- Hide quoted text -
- Show quoted text -
WNF-342 is Austrian and ran V-1 through V-4, seen here:http://rareaircraf1.greyfalcon.us/AUSTRIA.htm
Info:http://www.aviastar.org/helicopters_eng/doblhoff_wnf-342.php
Rob- Hide quoted text -
- Show quoted text -
Greater detailed history here: http://germanvtol.tofast.info/raf_review/rafreview.html
Interestingly, Theodor Laufer who worked with Doblhoff on the WNF-342
also had an independent design for a more advanced German jet
helicopter- the Laufer VE-RO, which is little-known. He postwar went
to France and helped design the tip-jet cold propulsion S.O. 1221
Djinn which was proposed for the US, but ultimately declined as a
"foreign" product.
Rob
My father Peter Sutton became the UK's top wind tunnel expert (apparently), working at Cambridge University.After the war ended he was posted to Volkenrode to investigate the research done there. I don't know much about it except that, and that he
brought his German secretary home with him and married her. I do have his diaries from that time but he doesn't mention work.
Sally Sutton
sallyjhsutton@gmail.com
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