If an Easy Sport 40 flies well off of land with a O.S. 46FX how should it do with floats? Thanks in advance for any help.......

If it takes off easily from grass, or "across" a paved runway, you should have no trouble with properly rigged floats.

I am famous for endorsing foam floats. In my experience they are lighter and more efficient than hollow floats....either fiberglass, blow molded (ugh), or built-up wood.

They usually recommend to go to the next size engine up. This is recommended to have extra power for breaking the suction of the water from the floats.

With the 46, it is already over powered...It will fly no problem with floats on it...It all depends what you want to do with it in the air... Puttin around or just cruising you could get away with a 40, 3D then maybe go to a 60 :devious:

rsdonomoore correctly reports that it is usually recommended to jump one engine size.

It's also wrong.

If you have trouble getting airborne, it's either float size or float rigging causing the trouble. You don't need any more power if the floats are installed properly.

Sorry Jim, you are wrong about engine size. For instance, if you are running a .40 on a trainer then add floats, it is wise to bump the engine up to the next size, say a .46. In this particular case though, he already at the max .40 size glow engine on his plane. So in that respect, yes he would have enough power.

I don't think jim is wrong.... Engine size all depends on the type of plane your flying off floats.. In most part all the float planes I have, have the recommended power.. And in most part its at the bottom of the scale.... A .40 size cub will fly off water with a 40 4-stroke... Another factor is your flying ability, If your not that experienced then you may need that 50 for a dumb thumb....
Nobody is wrong it's just that jbflier needed to give us more info on what he wants to do with the aircraft and if he is a beginner in r/c, a novice.??..etc...

Yes I can agree with that. I've been flying for only two years and have two floatplanes. Both are .40 size trainers and my LHS told me to add the next size motor to make up for the resistance of the water and the extra weight of the floats. I like the extra power anyway so it worked out great for me. If the water is very still I taxi and chum up the water to make a chop anyway. It's just a habbit I have. Gets the plane up faster too. I just flat out love float flying and hope that jb has fun at it too. I live in the Orlando Florida area and would love to come down to Jim's lake to fly. They have a really cool website. Looks like a blast.

I disagree. A slight increase in power with the appropriate prop will make the difference between flying and a snap roll ( spin )upon take off.

I would like to add my 0.02$:

I built several seaplanes in the past, especially pattern (F3A) models and slow flyers. I NEVER had to swap the engine to the next displacement to get airborne.

I also have to say that my models were also built very light and had good performance with wheels: no unlimited climbs, but enough power to keep it airborne and some extra power for when it is needed. Light construction is VITAL when flying off the water!!!

In my opinion, if the plane is already light, it all comes down to the weight of the floats: I build all my floats myself using high-quality, low weight isolation foam (white, 10 or 15 kg/m3) and sheet them with very low weight balsa and finally cover them with Oracover. On my [link=http://www.rcuniverse.com/forum/m_1123859/mpage_1/key_/anchor/tm.htm#1124170]latest 2m F3A pattern plane[/link], my floats' weight is 170g each (98cm length, 11cm wide - plenty of volume there).

Good, solid and light construction of plane and floats minimizes the need for a bigger engine. It helps getting on the step earlier and thus gain airspeed to take off from roughly any water surface. Of course, the added drag slows the plane down but should not be of any concern unless you need a lot of power e.g. to fly pattern. Just to stay aloft it ought to be enough.

Regards,
-Fabrizio