superstar float problem
 

Well, I mounted my cheap floats on my cheap superstar (cheap in price, $45 total for old floats, and new RTF Star from garage sale :D), after reading some of this forum, I decided to swap out the 40LA for a 40fp I had laying around, it's running a 10-6 at the moment. These floats have a fixed rudder on the left side, which I think is a little draggy, but I figgured I would give it a go.

It sits a little low in the water, and had a little trouble getting up on step, but made it ok, no wind at all, while on step, but just before take off, there seems to be a bit of tendancy to hook left, so the rudder may be dragging too much, I will try just removing it for now.

Not the prettiest take off, but I got it airborn, it seems to lean to the left a bit, it took about 1/2 of the available aleron trim to get it to straighten out, but then it flew pretty straight at all engine speeds. On the ground, I noticed that the alerons were not even, so there is something causing it to lean in the air.

I putted around for a while, and is semed fine, nice landing with only a little bounce. On the second take off run, the hook got me again, and on the third, I got the left float out early, and didn't compensate fast enough, causing a ground loop which killed the engine. I wonder if the trim caused the left side to lift off early????

The step is about 3/4" aft of cg, but thats the way the floats were set up, It already sits pretty far back with the rear of the floats almost under, If I move them forward, I will probably have to add a little length to the rear of the floats to compensate.

Questions:

1 any ideas on the lean to the left wiht neutral alerons? THe floats look square, and the engine is square to the mount.

2 can you post some pics of water rudders? I know most are only on one side, so how do you keep them from dragging?

Thanks!
Ken

RE: superstar float problem
 

Look carefully -- is there a warp in a wing?

Another thought -- are the floats toed-out a bit, or the left float toed-out, or a fraction nose-down relative to the right float?

One more --is the lateral balance significantly off?

RE: superstar float problem
 

britbrat: you may have caught it, the left float is tipped a little lower in the front, not a lot, but it is there. They are very square otherwise. The wing seems dead straight too. My first thought was a leak in a float, causing a balance issue, but it balances out dead center. I am a machinist, so I have a pretty good eye if I know what to look for.

Thinking about it, I suppose the float tip could explain both tendencies I am seeing.

I Straightened the float out by unscrewing the rear pillow block on the left float and bending the wire down a little. Then I moved the block out a bit on the wire to compensate. Now the floats look very straight across their tops. Incidentally, when I dismounted the rear block, the floats wanted to straighten out, so there must have been some slight difference between my superstar and the plane these floats were originally built for, Or maybe thats why they were at the swap meet in the first place.....:eek:

This problem aside, this has to be one of the easiest conversions I have ever seen, I know the superstar is a popular plane, but what are the odds of buying a set of old floats on spec, 6months ago, and then finding the same model of plane they were built for at a garage sale last week??? The wires were bent to slip directly into the original holes on the fuse, and the front trike mount hole was off by less than 1/16"

I went ahead and removed the water rudder for now, I will add it back later if everything else checks out.

Thanks so much for your help!, I wasn't even close to catching this problem. Hopefully that is the extent of it.

Ken

RE: superstar float problem
 

You may have found the answer. I've found that when a float or both floats, when planed out, are riding to close to the nose, the plane will want to veer to one side or the other. It's similar to a tail dragger with the gear too far foreward....very hard to control. This can be caused by improper setup or some down elevator trim. You want the floats riding close to the step, with everything behind the step up out of the water......Seaplane

RE: superstar float problem
 

The CG MUST be aft of the steps. If it's not, you'll have no end of problems on takeoff. I have a Superstar with Great Planes 40 size ARF floats, and a Tower 46, and I have been through exactly what you are experiencing now. Move the floats forward until the CG is aft of the steps by about 1/4". Until you do, takeoffs will be exciting.

RE: superstar float problem
 

Thanks for the advice, I took a closer look at these floats, and they don't start to taper untill about 6" forward of the step, so they are definetly plowing way forward of the cg unless I use full up for the takeoff and then even it out just as it breaks the water, not my prefered takeoff method, also they are a little small in the rears, so the plane taxies a little funny. I think I am just going to make some new floats, these were only $5 used, and now I think I think I see why.[:'(]

Here is a drawing of what I am planning on making, I am going to use 1.5" blue foam board, and cut left and right sides with a 5deg V bottom. I think I will leave the sides straight and then cover them with a little glass to toughen them up.

Ken

RE: superstar float problem
 

Those look pretty good. My floats are 38" long, and are a bit too large for the Superstar, although the water handling is superb.

I would make them at least 4" in beam, and don't worry about the V bottom: it's true they land a little smoother, but they also have more drag and are harder to get on plane than flat bottoms.

I think I would sheet the foam with 1/16" balsa (using contact cement) instead of glass. Glass doesn't really add any strength.

RE: superstar float problem
 

Haven't really decided on a covering, I like the glass as it's already fuel and water proof, with the balsa, I would still have to finish. I may just whip out a pair and try them unfinished, just the bare blue foam with a little tape on the planing surface, that way I can try a couple of different mount positions, and widths without spending much $$$ and time wise. I got a 4X8' piece of 1.5" foam, so I can use two pieces to get 3", or if I really need 4", I can put a 1" piece in the center. I stuck a 3" wide float in the water last night that I cut from junk foam, it suported 5.5lb(not counting it's weight) on the step just before the tail went under, so I think I will have plenty of boyancy for a 5.5lb plane with two floats. Do you base your 4" recomendation on flotation, or getting it up on plane?

Ken

RE: superstar float problem
 

Both. That's about how wide mine are. Here's a pic of the bird sitting on the floats so you can get an idea.

The url that describes them is: http://www2.towerhobbies.com/cgi-bin...?&I=LXEKH0&P=7

Don't forget some kind of additional ventral fin at the tail for stability. If you don't have it, you'll lose control.

Finally, if you haven't put your Superstar together yet, I strongly suggest reovering the wing so you can see it. On sunny days, all that white disappears. I can't see the plane at all, and have to get my reference from the floats. I've had good results with a dark blue or black on the bottom of the wing, and nothing but Coverite Neon Red on top, which comes out a very bright orange.

RE: superstar float problem
 

Hmm, I haven't seen the extra vertical fin before, I will have to build one. Is is supost to correct something in the takeoff run, or in flight? Those are some pretty big floats, They must add a bit of weight.

Once in the air it flys alright, It seems to like a little rudder in adition to the alerons to get around, but not sure that's really a fault, or just the dihedral. I am currently running an older os 40 fp so I want to keep everything as light and smooth as posible. The only real problem I was having was the takeoff runs, with unplanned oversteer and resultant spinout. I think these new floats should do the trick, but anything to make it a more docile flier would be helpfull as I would like to try doing a little training with it this summer.

As I said before, this was the RTF version with everything installed, But for $40 I wasn't going to be picky with colors :D. Once I get everything else sorted, I will probably recover the underside of the wings, at least the outer foot or so.

RE: superstar float problem
 

The extra fin compensates for all that float area sticking out ahead of the CG. Without it, stability about the vertical axis is diminished, and it's easy to spin the aircraft without intending to, and without the extra fin, you might not be able to recover. This could be the source of your instability on the water. I would almost bet on it.

Once you get "gradiated" from this seabird, I highly recommend going to some kind of low wing float plane. You'll find that almost anything high wing suffers from water penetration into the electronics area, because the floats (and hull on flying boats) send a tremendous jet of water against the wing saddle area. This is just not a problem with low wing float planes. The water bounces off the bottom of the wing. (See pic of my Heinkel 31, built from Ed Westwood's plans via RCM magazine.) My next sea bird, to be finished some time next year, is a 60" wingspan P-51 pattern ship on floats. Sorta like an American version of the last Schneider Cup winner, the S6B Supermarine racer, which was the basis of the Spitfire, the airplane that saved the world. I'm going to color it like the Reno Racer, "Miss America".

You're right - the floats on my Star are big. probably bigger than they need to be, but the water handling is superb, and the only times I ever flipped it over was when I was being stupid and not landing or taking off into the wind. It is kind strange having a trainer A/C with a wing loading of 32 oz per square foot, though.

RE: superstar float problem
 

Interesting. My step is about 3" aft of the CG, almost even with the trailing edge. No problems getting up on step or with tracking. ???

RE: superstar float problem
 

Beats me. Maybe you've got a better incidence between wing and float than I have, but both of mine were murder before I relocated the floats so that the CG was 1/4-1/2" aft of the steps. The little Heinkel wouldn't even plane- it just tried to push the float bows under the water. The Superstar wanted to porpoise along the water until I fixed it.

I do know one thing for sure- you won't find any planing hull boats with the weight bias forward. Too much weight in the bow, and a planing hull won't