Rumpler Twin-Hull Flying Boat

[McTodd]

The thread on Great War projects reminded me to look at Fred Gutschow's 'Die Deutschen Flugboote', which has information on Rumpler's magnificent giant flying boat designs. So with great delight, I found a three-page article in Flight, on their wonderful web archive, which some of you may enjoy:

http://www.flightglobal.com/PDFArchive/View/1930/Untitled0%20-%201553.html

Attached are a couple of photos from the article of a model.

 

[Jemiba]

There are some more informations in "Edmund Rumpler - Wegbereiter in der
industriellen Flugzeugfertigung" by J.A.Kranzhoff, Bernard & Graefe (publisher).
(3-view as an example)

 

[Libelle]

Concept drawing for the Howard Hughes HK-1 flying boat. A similar design...

 

[Cy-27]

There was an article on this project in the December 1930 issue of the American magazine Aero Digest (see attached).

 

[Tony Williams]

These twin-hulled flying boats (actual and proposed) have always intrigued me. They seem a logical way of providing more stability on the water, but I do wonder about what happened on landing if one hull hit a wave while the other was still out of the water. I assume that the thing violently zig-zagged all over the place until both hulls were well into the water.

 

[SlickDriver]

Tony -

I would say that the answers to your questions would be the Savoia-Marchetti S.55 that seemed not to have any such issues. Can't answer for larger aircraft but I have not seen any issues were reported

 

[Tony Williams]

It would obviously depend on the roughness of the water. In smooth water such as a protected anchorage, no problem. Logic suggests that if the waves were big enough for only one hull to hit one, there would be a massive increase in drag on that hull, which would tend to slew the plane sideways unless the other hull got in the water quickly.

 

[hesham]

Hi,

http://gallica.bnf.fr/ark:/12148/bpt6k9767475f/f584.image

 

[hesham]

Hi,

http://www.philsp.com/data/images/m/modern_mechanics_and_inventions_192903.jpg

 

[blackkite]

Rumpler trans Atlantic double boat hull all metal flying boat.
Span : 289feet(88m)
The center line of the two boat hull to be 59feet(33m)apart
170 passengers
10×1000hp water cooled engine (Keep flying with only 5 engines)
(Empty?) weight : 115ton, Fuel : 65ton, Payload : 18ton
Speed : 185miles per hour



The Dornier Do X was a answer to the request of the Reichsverkehrministerium (RVM). Their "Vorbereiting des Transozeanischen Luftverkehrs" (preparation for transatlantic airtravel) got several proposals. There were several proposals that couldn't be achieved in that time. Rumpler made one of these designs. The design used 10 engines of 1000 hp with pusher props. Span would be 94 m (308.4 ft). The design had 4 hulls and 2 stabilizers. Tails were connected to each other. Passengers were seated in the wing. The design of Dornier was easier to construct than this design.

Giants

 

[taildragger]

I've always wondered why anyone would design a flying boat with more than 2 primary hulls. Two hulls would split the displacement mostly evenly despite wave action when, but any more would cause the load to consantly shift between hulls in any swells, wearing out the structure. A monohull flying boat with outrigger floats arranged to both be in the water would have the same problem but much diminished.
Maybe it was assumed that nobody would moor a flying boat anywhere but in calm water, the alloys used were stressed so that they didn't fatigue or perhaps fatigue wasn't well understood.
Anyway, I've seen a few designs for seaplanes with 3 or more primary hulls but am not aware of any being actually built.

 

[riggerrob]

Yes Tony,
NACA film footage shows a twin-hulled flying boat model violently unstable in a tow-tank.
It is amazing how many dozen twin-hulled flying boats have been proposed, but how few have been built!

The last - that I heard of - was the Purcel Flight Wing circa 1970. It looked like a Burnelli Lifting body withpontoons grafted onto the lower chines. Plans were sold to amateur-builders - for a few years - but we never heard of any flying after the prototype.

 

[taildragger]

Yes Tony,
NACA film footage shows a twin-hulled flying boat model violently unstable in a tow-tank.
It is amazing how many dozen twin-hulled flying boats have been proposed, but how few have been built!

The last - that I heard of - was the Purcel Flight Wing circa 1970. It looked like a Burnelli Lifting body withpontoons grafted onto the lower chines. Plans were sold to amateur-builders - for a few years - but we never heard of any flying after the prototype.

In terms of behavior on the water, a twin-hulled flying boat shouldn't be any different than a twin-pontoon seaplane, of which there are many.