Latest TAG Amphib -Test flight off water!

[WaspAir]

The classic Martin M130 from the Clipper era used sponsons at the waterline (that look like stub wings) for the purpose of stability on the water.

 

[Aerofoam]

There was a sailboat design called "Wingmaran" that used a wing shaped "AKA"(Strut) as the outboard "Aka" and "AMA"(Float)
This pic looks like the design., but may have more going on underneath...
Worked well in mild conditions, but if the waves are big enough to pierce the face, you are screwed....
The advantage of the stub wing would be planing at very low speeds.

 

[WaspAir]

Sponsons are a little easier to see on the Boeing 314 in flight.

 

[Aerofoam]

Sponsons are a little easier to see on the Boeing 314 in flight.
View attachment 1161081

WOW. look at the AOA of those sponsons!

 

[WaspAir]

Incidence has to be high to prevent them becoming submarine-like bow diving planes during taxi. These were a next step after wing- mounted floats on earlier seaplanes such as the Sikorsky S-42. The PBY Catalina used wingtips that folded down to become floats for water ops, retracted to cut drag in flight.

 

[kolibri282]

Here is an attempt to visualize my idea of the gyro flying boat (yup, my name is not Leonardo). A boat shape (blue) is attached to the gyro fuselage (black) which widens as required to give some additional volume, so that the waterline is near the stub wings. At the end of the stub wings the landing gear swings upwards for water operation and is lowered for touching down on a runway. The lower part of the propeller is covered by a fixed spray protector. For take of and landing on water a foldable spray protector extends forward and upward, protecting the propeller from the spray of the boat fuselage. In the lower left corner I tried a 3view of the spray protector (SP), without anything obstructing it. The SP obstructs the lower part of the propeller, but with the SP extending far enough forward that should, IMO, work well enough. The root of the stub wings is a bit below the waterline, the wings have a small dihedral to stabilize the aircraft on water. The boat shape tapers backwards like a float to give enough lateral stability.
Looking forward to your comments.

 

[Aerofoam]

I think that is the right direction, but
making the boat hull as an add on shape would add weight and drag to the aircraft.
If the entire fuselage was a pontoon shape with the stub wing sponson, the stub wing would protect the prop from spray as well as house the landing gear and give stability in the water..

 

[loftus]

Here is an attempt to visualize my idea of the gyro flying boat (yup, my name is not Leonardo). A boat shape (blue) is attached to the gyro fuselage (black) which widens as required to give some additional volume, so that the waterline is near the stub wings. At the end of the stub wings the landing gear swings upwards for water operation and is lowered for touching down on a runway. The lower part of the propeller is covered by a fixed spray protector. For take of and landing on water a foldable spray protector extends forward and upward, protecting the propeller from the spray of the boat fuselage. In the lower left corner I tried a 3view of the spray protector (SP), without anything obstructing it. The SP obstructs the lower part of the propeller, but with the SP extending far enough forward that should, IMO, work well enough. The root of the stub wings is a bit below the waterline, the wings have a small dihedral to stabilize the aircraft on water. The boat shape tapers backwards like a float to give enough lateral stability.
Looking forward to your comments.


View attachment 1161086

I think there's just no free lunch. If one looks at FW Monohull seaplanes the engines are always high as these aircraft by design the passengers and cargo sit low in the water and the hull doubles as a flotation component and the actual fuselage of the aircraft. I'm sceptical that your rear splashguard would be effective enough to protect the powerplant without raising the whole aircraft, in other words the engine distance has to be raised higher off the water in some way, either raise the whole passenger component and powerplant higher off the water or raise the engine and it's thrustline as in a FW, a no-no in gyros I'm told. In other words one would have to build a much more bulky monohull that not only provided flotation, but also added separation from the water. In FW monohulls, with high engines, the monohull is an intrinsic part of the aircraft providing the added space and gross that is an advantage of monohull, FW monohulls can sit low in the water with their engines high. Sponsons or floats for the most part are simply necessary add ons to monohulls to provide lateral stability in the water. Another disadvantage of monohulls is that they are generally not great for docking as the flying parts are too low and get in the way in a gyro stopping and securing the rotor before docking would work I guess.. Floats keep the flying parts out of the way of the dock.
So I'm not saying a design such as yours would not be possible, simply that one would lose some of the advantages of monohulls that one sees in FW and especially with these foldable components etc things start becoming more complex. And then one loses the benefits that prompted your idea which is simplicity. A complete gyro redesign vs existing add on float designs is really the choice. These existing float designs already do exactly what a monohull would have to do, raise the whole aircraft off the water and provide flotation. In addition they already provide lateral stability without pontoons or sponsons. FW monohulls are really just enclosed boats with high thrust line engine placement .
If, I were to design a monohull gyroplane I might simply bolt a gyro onto a boat that the passengers sit in, and I believe somewhere I have seen a video of such a contraption. Possibly start with a design like an airboat and add a rotor.
Another point about pontoons etc they can add their own potential problems. I have seen a Searey catch a pontoon in choppy water. Fortunately it broke the pontoon and did not flip the plane, still had to be towed back to shore with one wingtip in the water.

Bensen B.8 Gyroboat

Details of exhibits at the helicopter museum

helimuseum.com

Gyroboat..

Wonder if the gyroboat is alive somewhere? Or worth bringing to live? I think Bensen also was into gyroboats. Could be a solution in some places and ad safety to it as water softer than land.

www.rotaryforum.com

 

[Abid]

Having certified and established Searey production line in 2012-13 and helped initially in technical advice for Wave amphibian airplane and done all the load and structural work on American Legend Aircraft amphib floats (Super Cub floats), you need to have the engine high if you are going to go with a full hull. There is no other way around it. All the centerline thrust fans are going to have a hissyfit. This is the gyroplane market status. To get the design right requires many iterations of design. There is no demand to justify all the $$ on those iteration in an amphib monohull gyroplane. It would not garner the market it would deserve. The weight problem is not as bad as one would think. The whole Searey Elite with 914 engine I was able to engineer down to 915 pounds empty weight from 1040 pounds they had in EAB version and it could have still be lowered if they had more money to spend.
If you did floats on an existing gyro, its an easier solution on existing machines and cheaper and it probably serves the market demand ok because I do not see a lot of gyroplane pilots looking to pay $160k plus an amphib gyroplane would cost.

 

[WaspAir]

Your hull shape could benefit from some shaping to improve water handling. Note that all the classic flying boat hulls (and even floats) have some sort of keel, sister keelson, chines, skeg, or the like to make it a better boat and help it break the water.

If you have lots of lateral surface area down low, you may need to add a big mast fairing / fin up high to balance it so that you don't get too much coupling of adverse roll with yaw.

 

[kolibri282]

Q: Note that all the classic flying boat hulls (and even floats) have some sort of keel, sister keelson, chines, skeg, or the like to make it a better boat and help it break the water. /Q
Of course you are right, there is a lot of room for improvement. I might have added a few of these details if not for my lack of ability at drawing and I hesitated to put more time and effort into an idea that will probably never be realized. Flying boats have always been my favourite aircraft, I studied their design in some depth. The idea that you can land on 70% of the surface of this planet and spend some time in a beautiful remote spot always appealed to the romantic side of me. I will, most likely, never own one of those marvelous flying yachts, that plied the skies. The closest I have come to this was, when I met my wife and we both set out to sail the Swedish coast in a 14 feet foldable dinghi, sleeping in our tent on remote islands and having a great time until the 30 liters of water we had on board (and the dozen or so bottles of beer) were used up and we had to set sail again.

As for the lateral surface I think that floats put that area far lower than would my design.

Catalina flying Yacht
Catalina flying Yacht II


Please note that I claim the rights to the picture below, I might use it for an article on our tour at some time.