I am considering building a swoose oldtimer in the seaplane configuration. From other posts I have read in seaplane section concerning the swoose the plane was tail heavy, flew squirly, did not sit on the floats properly. Not a good start. People gave up trying to get it balanced. I am planning on using a short kit from Klarich kits (either 54" or 78" wing span) and modify the Model Airplane News plans of the float plane version (62" wing span) to fit the new size.

I would like to address the issues as listed above in construction if possible. Any ideas?

Would the fuse require any special construction when converting from and old timer to a float plane?

The floats will be permantly attached. Can wheels be attached to the bottom of the floats for grass flying?

See pic below of the 62" version and how it is sitting on floats. I wonder if some production floats (sig smooth etc) would fit and float the 54" or 78" planes better?

Thanks,
Mitch

Very exotic looking bird! One flew at Havasu years ago, but I didn't check out the details, so I don't know if he modified it. From the photo it looks like the rear of the floats doesn't have enough floatation.

I think commercially available floats would be a good idea, but stay away from Sig, Goldberg and Great Planes. They are all too heavy. Check with SEAPLANE on this forum, or one of the other suppliers of sheeted foam floats.

It also seems that the nose of the airplane is very short, which would contribute to tail heaviness. The rule of thumb for glow powered sport planes is that the distance from the CG to the back of the spinner should be about 50% of the distance from the CG to the rudder hinge line. Maybe stretching the nose would help.

Keep us posted on your progress.

Jim

PS: Re wheels on the floats; that's not very practical. If you try to build them into the floats they will seriously mess up the water handling, and if you used a detachable dolly, you would be adding a lot of weight and drag and probably have trouble balancing the plane. Either way, you would have to use bicycle gear (two wheels on each float) because the rear of the floats won't let the tail come down far enough for a tail wheel to work. And don't even think about making the nosewheels steerable!

The good news is that the floats by themselves will work fine on soft snow or even wet grass.

J

Thanks for te reply Jim,

The SIG smooth are 41" so the fuse will need to be around 53 inches or so right? It looks like if I want to use those I will need to make the 62" ws with 47" long plane. That way I can extend the nose to balance. Or I can build the 78" ws plane that is 60" long and have some 45" long floats made.

Will all that vertical surface area between the floats and fuse cause any bad flying habits?

I will attach the pic that got me started in all this mess...

Mitch

Check with SEAPLANE or one of the other suppliers about the capacity of the floats. The weight of the airplane is more important than its length.

Yes it will. Make sure you have plenty of side area at the tail to offset it. (Vertical tail plus sub-fin should be at least 10% of wing area.)

Jim

I always thought these were very sharp looking planes. I am interested to hear how your project comes out.

Jeff

This will be an interesting project. The swoose kind of reminds me of the old racing seplanes. See below supermarine S6.

Perhaps the best approach will be to build one of the short kits and then weigh it. Then the floats can be made. I do not have an idea how much it will weigh at this time. I expect it will fairly heavy as I intend to use a 4 stroke and wouldn't the fuse/wings etc. require waterproofing?

Can seaplane make custom floats and make them so the plane will float correctly for my application? I will see if I can contact him.

Mitch

No special waterproofing required inside, just take pains to be sure nothing can get through the covering. Nyrods, steel pushrods in a tube or even just pushrod exit covers work well enough to prevent water from entering there. Use foam wing saddle tape on all four sides of the wing to fuselage joint. Basically, if the airplane is fuel proof, it is waterproof.

Jim