To Float guru or STOL guys. Please lend your engine power experience. This is a pix just like he's Decathlon 46 , seller said from UK Warehouse, before a fence jumped up and broke the inner one side axle mount and cracked taildragger pivot mount. Not hard to patch, if go to floats. I bought it with out TX , RX , servos or motor, my question is. I made a jig and am 90% done putting on SeaPlane Supply foam floats (V-bottom flat top). ( have it , for now, set to 2% positive inc AoA, and Step is 3/4" behind CoG. Tip of floats about 3.5" in front of prop. Will add inside items each time checking CoG , and L-R balance) Ok heres the $64 question. I bought a Magnum XL 52R 4 stroke. Plane is a 62" w/s. Plans says [I guess for wheels] req a 35 two cyc or 52 four stroke. I do not need to do rolls or loops , will a XL 52 FS lift this of the water ? ( I'll make my kids go out in the cold water and make some 2" waves) On a scale the RX , RX batt, 5 servos, cheap tank, Magnum 52fs, plane, floats, alum streamline struts, allweigh about 6 lbs 7oz. A pig , right. SPEC said flying weight 2300g (5.1 lbs)

I doubt it will get off the water with that engine, much less fly well once it's up. I have that engine on a .40 size Cub and it's just barely enough to fly it with wheels. To have the Decathalon to fly like it's supposed to, you'd likely need a .65-.70 4 stroke.

You should be fine . As long as your floats are set up properly you should come out of the water easily..It will come up onto the step and fly its self out when it is ready...I think you will have more power than you need . I don't know the motor though . A lot depends on the angle of incidence between your wing and floats..

Hey Brisco welcome to the forum.

OK first off I am not a stranger to float planes so I think I can offer some useful information and I have flown in the past some forty sized Decathlon on floats that I was helping a fellow with. Can't remember if it was GP, CMP or the Pheonix from viet nam.

Anyway the weight as you described is completely within the ballpark for that airplane and yes float planes are heavier but even with the extra weight many will fly better as the floats themselves act like stabilizers.

One item I would like to address is the Step/CG relationship and for that size airplane is a little much at 3/4inch aft. This is a item that may make it harder to get up on the step and that is not what you will want for an airplane that may be underpowered but more on that in a bit. For that airplane I would prefer to have the CG anywhere from directly at the step or up to around 1/4 inch aft of the step. Correction: what I intended to say is The Step up to a 1/4 inch aft of the CG.

On the power thing, The trouble with the little fourstroke you mentioned is first its not a powerhouse and it is grossly underpowered even on wheels. I don,t care what factory recs say and often some of them are just hogwash. Now the airplane I mentioned that fellow had put a small fourstroke of some sort on it and I flew it, and as expected it was a dog and underpowered. The real problem is an underpowered float plane seldom lives very long especially when the fellows are new float flyers.

Now the fellow with that Decathlon did as I suggested and that was to get over the fourstoke phobia and use an OS 55AX or even the .65. He did just that and the result was an entirely different airplane that be became a joy to fly. The whole gotta have a fourstroke thing is overrated and many airplane types work better with the two stroke.

If you must have the fourstroke my minimum would be .70.

Here are couple of pics of that ship I was talking about:


The last two photos is what I did with my Decathalon, turned it into a Champion Lancer or as some would say the Flying Turd:

Thanks guys, ( JB and jester) The vote is 2 of 3 say , more than a 52FS. I'll go look at a 70, their only $30 more. I just dug out my reciept and box (Magnum XL52RFS Blue) got it from Hobby People last July, Paid $99 for it, test run 2 tanks on her last Aug. I think I'll sell it for $95 + SH. Next year I am leaning toward a elec Reaper Drone project. If I do anything more in Glow, ( a spare Super Tigre g20 ) a scratch AIRBOAT ,for my granson. I know I'll stay around water for flying places reasons, SO I'll doubt being smaller than 60" w/s and to not have much use for a 52FS going forward. Thanks again ( ya know what would be fun , a KingFisher , or Hellcat on monoFloat )

B.Sco<br type="_moz" />

Yup monofloat may be fun: