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Old Mar 25, 2007, 07:45 PM
Back in black............
dodd city tx
Joined Sep 2005
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help me make my plane float

I started this tread http://www.rcgroups.com/forums/showthread.php?t=662103
and was directed here on rcg. I think I have the cg determined please look at the pic and tell me if you agree. I don't have a clue as to what the AOA should be on a float plane. The wing isn't bolted down once it is it will set level. please any advise you can give me thanks


Mike
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Old Mar 25, 2007, 08:54 PM
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Looking at the last picture you put up... your floats are definately not lined up the way they should be. When you come in for a landing.. (providing you can even get it to fly off the water).. there's a strong chance that you're going to "nose-in" on every attempt due to the angle your floats are at.

Although i'm no expert when it comes to floatplanes... you're definately going to want to level those floats out so that the floats are level with the wing. And set up your "step" on the floats, so that it's right at, or no more than 1/2 inch behind your center of gravitly.

From that point, you should have no trouble "tweaking" it to where she flies sweet!

Hope that helps you..





Fun and safe flying
~Tim~ (TheDustyPagan)
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Last edited by thedustypagan; Mar 25, 2007 at 09:33 PM. Reason: Stupid typo's, lol
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Old Mar 25, 2007, 09:18 PM
Back in black............
dodd city tx
Joined Sep 2005
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Tim thanks for the info. I new that the AOA wasn't right but I didn't know what it should be. I just used the rear mount that came with the floats to try and set the cg on the floats if that is the right term, I spent a lot of time looking at the planes on this forum Dot know why I didn't think to post here first. It looks to me that real planes have some degree of AOA on the floats but most of the ones here don't.


Mike
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Old Mar 25, 2007, 10:05 PM
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Mike, the wood prop will get beat up by the spray..best to go with a composite.
The plane looks like the old ' Miss Martha ' fun fly model...
The AOA is usually just a degree. The floats do have to be solidly mounted. A water rudder set up makes life on the water a lot easier. art
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Old Mar 25, 2007, 10:27 PM
Back in black............
dodd city tx
Joined Sep 2005
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Art I never would have thought about a wood prop being a problem thanks.

years ago when there was a club her there was this great old guy that built kits and sold them. this is one of his plane. It was scaled up from a 20 sized that would always when the limbo contest because it could fly so slow. I have one of the 20 sized planes to.

I have a duel water ruder set setting on the table but I do have a ? about that. I want to be able to take the floats off and on real easy would it be best to use a cable or mount a servo on the floats. I can watter proof the servo and just run a y harness to plug it into the ruder servo.

thanks for the info now I can build my mounts for right amount of AOA.

Mike
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Old Mar 25, 2007, 10:32 PM
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The servo would be the easiest way to go to be easily converted back and forth.
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Old Mar 26, 2007, 12:20 PM
Back in black............
dodd city tx
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I was going to use the main gear thats on the plane to mount the front of the floats and then use 3/16 steal wire for the rear mount. will this be ok?

Mike
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Old Mar 26, 2007, 08:03 PM
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Crossville, TN
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Mike, that is the way most conversions are done. Front and rear spreaders seem to help as does diagonal strut bracing .
My own setups always include toe in on the floats. Small planes get 1/16" and my six footer had 3/8 ". ( I get a lot of flack on this, but it has worked for me for over 30+ years of water flying.) My float planes have very straight take off runs.
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Old Mar 26, 2007, 08:12 PM
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The chord line of the wing should be between zero positive and 3 degrees positive. Your pictures show it about 20 degrees positive. As we say here in Tennessee, "that dawg won't hunt".

The step goes under a point at 40% of the mean aerodynamic chord. Since you have straight wings, just measure from the front to the rear and multiply by .4. 10" wings, step goes 4" back from the leading edge. Some people say an inch behind the balance point. It's about the same.

Balance the plane after you add the floats. It'll probably balance oK, but if you have to adjust the weight add it to the nose or the tails of the floats. It should balance in the same place as it did with wheels. Balance laterally, too. The side with the muffler is heavier than the other side.

3/16 wire is pretty heavy for the rear mount. 1/8 will work, but use a small music wire spreader bar between the floats ...it's actually a non-spreader bar.

Master Airscrew props are not the quietest or most efficient but they take punishment well from spray. You might find that you want to shorten the pitch by one step. If you fly a 10-7 normally go for a 10-6 or an 11-4.
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Old Mar 26, 2007, 09:50 PM
Back in black............
dodd city tx
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thanks for the info guys just what i needed to know.

Art This is my first try at flying of the watter but I have been doing front end alignment on cars and trucks for years and I can tell that a little toe in makes things track straight. For that reason I had plane on a few deg.


Jim we have the same saying here in Texas. I have a 12" cord so the step should be at 4.8" right. I had plane on balancing the plane after the floats are installed with any adjustments made to the floats as the plane balance perfect for wheels both front to back and side to side. No muffler here though this thing runs on electrons. why is a shorter pitch better for floats planes?

I do have one more ? I am not having any luck covering the floats and getting them to look like i want. not my forte. can I prime and paint them with out any adverse effects?


Mike
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Old Mar 27, 2007, 12:54 AM
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Mike..get some 3/4 oz. fiberglass cloth from your LHS. MinWax waterbased polycrylic clear paint can be found in most paint departments. Pick up a few cheap 1/2" brushes. You will need a pair of decent sissors..look for the ones that say 'Titanium' on the pkg. They are in the $8 range in dep't stores.
Simply cut out the patterns about an inch oversize. Do the bottoms from the step forward and another piece for the step rearward. The sides and the top can be done separately or all in one piece.
Just lay the glass on and brush the clear MinWax through it.Start at the center and work out to the sides. Any wrinkles brush out.
Do the bottoms and let them dry..about a half hour. Trim the excess glass off with 220 sand paper.
Next, go for the tops/sides. Hint: A handy 'loop' of sticky side out masking tape is used to stick the odd strands to .
When dry and trimmed, brush a second coat on and let dry. This paint dries water proof.
Color ? Look in the paint section of any craft store..you are looking for ceramic paint. There are about a hundred or more colors...small size is about 80 cents, large size a couple of bucks. I use 'Delta Ceram Coat" because that is what is available..any brand will work.
Thin about 10% with windshield washer fluid and brush it on. It will dry dull in less than a half hour. Thin out some of the MinWax clear the same way and brush it over the color to give it a shine. Sometimes it takes two coats. The color of the washer fluid doesn't affect the color of either the clear or the actual color you choose.
Do not return any thinned out paint to the original quantity.
Easier than you think !! Try it..you'll like it !
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Old Mar 28, 2007, 06:39 PM
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>>why is a shorter pitch better for floats planes?<<
Because they are a little heavier, and a little slower, and the shorter pitch is like dropping your car from 4th gear into third gear to climb a hill. You'll get better acceleration, steeper climb, and actually a shorter landing approach, with the shorter pitch. Just not as much top speed.
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Old Mar 28, 2007, 09:53 PM
Back in black............
dodd city tx
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Jim I understand. Well I think I have it set about right. The step is a little farther back then you recommend Jim but it balances out right. take a look at the pics. I did take it out back to the pool behind my house and set it in the watter. I et nice and level. I kinda shook it around and it is stable. cg for the plane is right on the step . with the plane ready to fly it sets with the watter about .75" up on the front of the floats at the thickest part and about.25" up on the back of the floats.

Mike
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Old Mar 29, 2007, 08:12 PM
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Well, I have flown planes that had the prop out in front of the floats, but the floats are really supposed to stick a little bit forward of the prop. 20% of the prop diameter is a guideline. If for no other reason, it protects the prop when you are beaching the plane.
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Old Mar 29, 2007, 08:25 PM
Back in black............
dodd city tx
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ok tried here out tonight. I went out side and set her down on the pool behind my house. floated around just getting the feel of the plane in the watter not giving it very much gas. I went to the far end of the pool and throttled up instead of coming up on the front of the floats it kinda dug them in. If this was a boat i would say that the prop angle was off. I do have a bit of down thrust built in the plane and then a small spacer on the top part of the mount but this was done to get it to fly right power on and power off.Please look at the pics and tell me if you think that is what is causing the digging down problem or is it something else.


thanks Mike
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