samsrc

My Feedback: (4)

I'm new to float flying, and I'm about to set up my first set of floats. Now after doing some research through these forums, I've noticed that most people seem to have similar theories on how to set them up. The common theories are that the floats should be about 75-80% of the fuse length, the step should be set on the CG of the plane or are a little aft, the floats should extend about 10-15% forward of the prop, and the incidence of the floats should be set to the same incidence of the wing (or a slight positive incidence of the wing in relation to the float)

This is all great, although the one factor I can't seen to find any info on, is how far apart should the floats be set up?? Is there a rule to this??

Sam

Goinstraightup

My Feedback: (26)

Great question Samsrc, Usually you will be attaching your floats to an existing wheel bracket on the plane. What I mean is that your forward gear on your taildragger planes and your rear main gear on your trike planes usually becomes one of your mounts. Then you make the other mount accordingly. For high wing trainers (that have a flat bottom fuse), I like to just make another main gear identical to the rear main gear and mount it right behind the cowl. So to answer your question, the set distance apart that your gear already is, becomes the span between the floats.

All the set up figures you mentioned are true. Make sure that your float tips end up at least 2 inches in front of your propeller or more. Also, the incidence of the wing matching the incidence of the floats is true only for flat bottom wing trainers. If you have a symmetrical wing then you want to have positive incidence in your floats. For my low wing Cloud Dancer 60, I used 3 degrees and it worked great. What that means is that the nose of the plane is further away from the floats than the tail when looking at the plane from the side. It looks kind of funny, but my Cloud Dancer worked great and I'm glad I had the positive incidence as the water handling of the plane was superb.

jrf

My Feedback: (551)

The Rule-of-Thumb is 25% of the span.

Jim

seaplane

I agree with Jim, the spacing should be about 20%-25% of your wing span. A high wing plane will standup to a cross wind better if the spacing is wide. Another measurement is the distance of the plane to the tops of the floats. Generally, the tops of the floats should be at least 2" below the bottom of the prop arc. This will aid in keeping the spray away from your prop......Seaplane

samsrc

My Feedback: (4)

Well I'm installing floats on the Hangar 9 clipped wing Taylorcraft. It has roughly an 86" span, so going with your 25% formula roughly 22" apart??
The floats I have are sea-commander 46" floats.
As well the Taylorcraft has a semi-symetrical airfoil, so does that mean I should put in a degree or 2 or positive incidence??

Sam

JimCasey

My Feedback: (1)

Use the positive incidence. You really don't have too much unless the plane porpoises on the takeoff run. Holding a touch of up elevator will stop the porpoising anyway.