Land-Based Plane With Jettisonable Float: Do-Able or Not?

[KJ_Lesnick]

I'm wondering if it was technically possible in the 1930's or 1940's to produce an airplane that could take off of water, and land on either a land-base or a carrier.  The idea would be the plane would be a land-based plane fundamentally with the provision to attach a float under it so it could take off of water; the float could be kept on and the plane landed, or the pontoon could be jettisoned and the plane would now be just like a land-based plane with a retracted gear.  It would then land on a land-base.

The idea is that you'd only need to build one plane that could be used for sea-plane and land-plane ops.

[Jschmus]

I'm not sure about the jettisonable float, but there were a number of aircraft built during that period that were built in land-plane and float-plane versions, the Vought OS2U Kingfisher in particular springs to mind:
http://en.wikipedia.org/wiki/OS2U_Kingfisher

[rickshaw]

The Japanese floatplane fighters had jettisonable floats but had no landing gear.  It was intended that if they encountered land/carrier based fighters with superior performance they could jettison their floats and thereby fight their opponents on a more even basis or flee with the decreased drag giving them greater speed.

[Alvis 3.14159]

I didn't think the Rufe had jettisionable floats, but I don't know much aboot any other floatplane fighters of the IJN.

The Stukas designed for the Graf Zeppelin had jettisonable wheel spats to allow for ditching, so there's that as a precedent. Kind of.

The technical aspects of having a float that could be dropped would produce some penalties, such as requiring the plane to carry landing gear and the attendant structure even if it was never used, and the required strengthening of where the floats would have to be attached as well. Given the time frame, that would have likely added some performance penalties that wouldn't have been considered worth it.

Now, to start with a clean sheet, twin floats or single with outriggers. Hmm. The Rufe used the latter design, and it seemed to have decent performance, but the Spitfire had twin floats and wasn't a slouch either. If I was going to jettison floats, I'd prefer to drop one main one rather than two big ones, as having either one hang up would be a nightmare.

Given enough horsepower, I think it might be possible to have been done, but would have been difficult to pull off.


Alvis Pi

[Weaver]

Don't see why not. You could use P-40/Corsair-style rearward retracting gear so it's not fighting the float for centreline space.

[Hobbes]

The extra weight would eat into the (already not very large) payload for smaller aircraft.
You'd also have to make damn sure that the float stays in place during a water landing, but also can be ejected with absolute certainty when needed.
And you'd end up throwing away large, expensive pieces of kit every time you jettison a float.
A flying boat with retractable wheels is a much simpler solution. 

[sandiego89]

I agree that is doable and could lead to some very interesting quasi-seaplane WHIFS- especially for small fighter aircraft.  But I also agree with the comments about weight panalties and that retratctable wheels on a flying boat is an easier solution- the grumman duck could land on water or on land with retractble gear and even could be fitted with a tail hook for carrier ops. But flying boats come with their own penalties of weight and drag.   

The M6A Serian is a good example of detachable floats.  Desiged to be launched from a submarine it could keep its floats and land back next to the submarine, or for a high priorty mission (like the planned Panama canal strike) it could jettison its floats for longer range.  No landing gear was fitted, but a training version was built with conventuional landing gear so I could see both being fitted (with the weight penalty). The wiki page for the Serian shows pictures of both designs. 

Lots of possible fighter candidates for your time period, with radial engines likely being better: Wildcat, Hellcat, Corsair, Bearcat, P-47 etc.  I would avoid inline engine with large radiator scoops like the P-51, hurricane etc.   

Go for it!

[tigercat]

What was that aircradft where  the whole bottom extended on stilts and it became a planing surface.

[Weaver]

What was that aircradft where  the whole bottom extended on stilts and it became a planing surface.

Blackburn B-20: http://en.wikipedia.org/wiki/Blackburn_B-20

[RussC]

Looking at the Goodyear experiments with the Inflatoplanes, maybe a Inflatofloat design would be the way to go. In fact it could be carried as a hidden compartment and used as a seaplane option as needed. The Goodyear design would be something that once deployed could not be deflated and then retracted again.
 
 Here's a Whiff storm / Brainfart....A Japanese version of the flying boat fighters like the Saro A1 or its contemporaries.

 Saw a Whiff once on Hyperscale where someone made a Jet Rufe.

 The high performance Seaplane was a IJN specific field like the Kyofu and the Zuiun designs. The Seirans that were embarked for the Panama Canal strike supposedly had US markings and were going to be launched floatless as the pilots had decided on a one-way trip in advance. Before surrendering to the USN, the 1-400's disposed of the sierans into the ocean as the US markings were a big Geneva accord no-no, equated with piracy and capital punishment at sea.
 
 The only seaplane that I was aware of with ability to drop floats in flight was the Shiun E15K1 (painted cloud) which was also unique in having a contraprop.

 Dropping a big heavy aircraft part in flight was not a trivial thing, needing lots of testing to get it right.

[PR19_Kit]

 The only seaplane that I was aware of with ability to drop floats in flight was the Shiun E15K1 (painted cloud) which was also unique in having a contraprop.

Somewhere in The Loft I have a 1/72 kit of that thing, by Aosima perhaps? Long glazed canopy, radial engine and 2 x twin bladed contra-props from memory.

[sandiego89]

RussC, good catch on the M6A Serian.  I just pulled out my reference (Aichi M6A1 Serian in Wings of Fame Vol 17, by Robert C. Mikesh) which confirms that for most combat ops (like the planned canal attack or the just aborted raid on Ulithi at wars end) the  Serian would have been launched floatless.

It states that "in the early planning of the design the floats could be jettisoned in flight, but when it was discovered that their weight would adversely affect the bomb or torpedo load, this feature was not developed."  For optimum bomb loads the Serian would be launched floatless.  With floats a load of 250kg (551 pounds) could be carried.   

[rickshaw]

I've been thinking about this a bit more.  What you could do is have wheels in the fairings to the floats, such as on the Stuka and its spatted undercarriage.  That way, both types of undercarriage would share the same take up points in the wing and you couldn't be carrying extra local strengthening for each type of landing gear (wheeled and floats).  Once you drop the floats the wheels would be exposed and you could land with them.  Removal of the floats would decrease drag and weight, hence improving performance.

[RussC]

 The only seaplane that I was aware of with ability to drop floats in flight was the Shiun E15K1 (painted cloud) which was also unique in having a contraprop.

Somewhere in The Loft I have a 1/72 kit of that thing, by Aosima perhaps? Long glazed canopy, radial engine and 2 x twin bladed contra-props from memory.

  I remember those Aoshima kits! I built that one and the Ki-100 and they had a Myrt + Zuiun, plus the only 72nd scale kit of the Bell P-63 Kingcobra that could be had in the early 1970's. Raised panel lines in places not realistic, baseball sized rivets in locomotive steam boiler patterns, fuselage halves that did not go together unless sanded planar on a flat block, and kit boxes made of cardboard just a shade thicker than typing paper, box art done with magic markers and hi-liters, and decals that turned to confetti in water. They also came with glue, that little green translucent squib that had the stringy-est glue on earth. Us collectors who wanted the wider selections of aircraft nonetheless built these monsters, plus VEB from East Germany and even a few Starfix. These only made the better stuff seem even more pleasurable to build. Rule of thumb, any Aoshima,VEB or Starfix built should be followed with a Heller, Monogram, Hasegawa or Airfix in order to decompress'.

[PR19_Kit]

  I remember those Aoshima kits! I built that one and the Ki-100 and they had a Myrt + Zuiun, plus the only 72nd scale kit of the Bell P-63 Kingcobra that could be had in the early 1970's. Raised panel lines in places not realistic, baseball sized rivets in locomotive steam boiler patterns, fuselage halves that did not go together unless sanded planar on a flat block, and kit boxes made of cardboard just a shade thicker than typing paper, box art done with magic markers and hi-liters, and decals that turned to confetti in water. They also came with glue, that little green translucent squib that had the stringy-est glue on earth. Us collectors who wanted the wider selections of aircraft nonetheless built these monsters, plus VEB from East Germany and even a few Starfix. These only made the better stuff seem even more pleasurable to build. Rule of thumb, any Aoshima,VEB or Starfix built should be followed with a Heller, Monogram, Hasegawa or Airfix in order to decompress'.

Aaahh, the joys of Vintage Plastic modelling. 

I'd forgotten the 'green translucent squib' thingie, but your phrase describes it EXACTLY.