Highly risky . Unproven. Looks quaint
Indranil wrote:10. Sponsonless. New method called SAGAR, also aids in STOL.
So this an US-2/AG-600 class aircraft!!
. Will need sub scale model to be tested and control systems proven before it can be put into a full aircraft. And I am a little confused here.
1. They have made the float/hull stable like a ship (by having metacenter above CG).. So I guess in a static/rest position it will be stable and wont topple.
2. However, while take off, since it is a planing hull (where , weight NOT =
buoyancy, a portion of weight is supported by hydrodynamic lift in water), the stability is an issue as the water plane area reduces. I guess this stability augmentation scheme is for these regimes.
Again, I am not sure if the they have thought all this out. So let me summarise what I THINK
(could be wrong) they have done.
The stabilisation scheme (on water) is like a conventional boat. To possibly cater to stability decrease during high speed taxiing and take off run, and landing , they have active stability augmentation. I think the more difficult problem is stability during landing where it touches down in a flare and there isn't enough waterline area for it to have transverse stability.
Which brings back the question. Have they REALLY thought this through ? Who are the customers for this
. Turbofan engines ? Why ? A turbo prop will be more efficient. Is it going to be a transonic plane like an airliner that flies at mach 0.85 or so, having a swept wing and hence turbofan engines , or is it going to be a straight wing, fly at mach 0.65 odd, plane that is meant for SAR and patrol and stuff able to land and take off in pretty rough sea states ?
If it is the latter and not airliner substitute, that lands and takes off in calm water and the risks involved in active stabilisation and the development effort involved , this entire thing seems ill considered and frankly quite overdone.
Which brings us back to the question.
Question : So how does a catamaran /outrigger canoe differ from a traditional monohull (yeah, catamaran have multiple hulls .. that is not the question. how do they differ in working?)
Hint/Ans : A catamaran /outrigger canoe are different in how they work from a traditional monohull . A monohull is stabilised by gravity (just CG and buoyancy at play here). A catamaran /outrigger are geometry stabilised. A traditional seaplane is like a catamaran /outrigger canoe with the outrigger floats, while what HAL is proposing is a monohull with artificial stability augmentation in critical phases. If they want to get rid of the outboard wing floats, they are better off going for the Boeing 314 Clipper / Dornier flying boat kind of scheme, and they can put the landing gear in that as well for amphibious operations, in addition to make that sponson generate lift