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LT-40 on Floats-No go!

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LT-40 on Floats-No go!

Old 05-07-2005, 10:35 AM
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kdoughty
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Default RE: LT-40 on Floats-No go!

WE FLY A LOT OF LT40'S AT OUR FIELD. THAT PLANE IS UNDER POWERED WITH A 40. IT NEEDS AT LEAST A 45 .MY LT40 WEIGHTED ABOUT SIX AND HALF LBS. IF YOUR FLOATS WEIGHTED 2 LB, I DON'T THINK A 40 WILL GET IT OFF THE WATER. IF IT DID, IT WOULD NOT FLY WELL.
Old 05-07-2005, 11:23 AM
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Wayne22
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Default RE: LT-40 on Floats-No go!

Sure more power will overcome anything, but lets try and finesse what he has got to work with and see if we can get him off the water.

Jim Casey gave a lot of good ideas. I have to agree from the photos that I don't see that engine/prop putting out a lot of thrust..I think there is potential there.

Also there is a lot of spray coming up between the floats..some water drag there somewhere.. Are the floats parallel with each other, and with the fuselage? Are they flat bottomed floats?
Old 05-07-2005, 01:25 PM
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Default RE: LT-40 on Floats-No go!


ORIGINAL: nony

Sure more power will overcome anything, but lets try and finesse what he has got to work with and see if we can get him off the water.

Jim Casey gave a lot of good ideas. I have to agree from the photos that I don't see that engine/prop putting out a lot of thrust..I think there is potential there.

Also there is a lot of spray coming up between the floats..some water drag there somewhere.. Are the floats parallel with each other, and with the fuselage? Are they flat bottomed floats?
Go ahead and finesse him all you want and if he does get it off, he'll probably hate you for it. It appears he is a newbie (I could be wrong) and is probably not good at flying a low powered heavy airplane on the wing so to speak. If he does horse it off, he'll probably stall it immediately after lift off and in the drink he will go. I've seen it many times.

But you fellows continue finessing. Some could probably fly his plane, but not many and apparently he can't.
Old 05-07-2005, 07:04 PM
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Soloflyer!!!
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Default RE: LT-40 on Floats-No go!

Obviously the 40LA isn't the right engine for float flying, however I have enjoyed the experience and have learned alot. However I will keep the floats for another model or jack up a bigger engine for the LT-40. The 40LA is fine for training on and has adiquit power for land takeoffs, so I will put the wheels pack on and get pack into it again. I will admit that I am not the most experienced pilot.
Thanks for all the comments posted in this forum.
Old 05-07-2005, 08:12 PM
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Default RE: LT-40 on Floats-No go!

I just thought of something... Did you put packing tape or any kind of covering on the bottoms? I had a plane I put packing tape on the bottom of the floats to make them slicker and I got a small slit in one of them. It was hard to see just glancing at it, but when in the water and under speed the slit would open up and it would ballon up creating LOTS of drag. I could not figure out why it was so hard to get it off the water all of a sudden. I changed the tape when I finaly saw the slit and life was good after that. Just a thought......
Old 05-08-2005, 02:09 AM
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Soloflyer!!!
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Default RE: LT-40 on Floats-No go!

No, I have not covered the Floats, infact the bottom surface of the floats is actually quite rough, as in little bits where the foam has broken away- nothing drastic however. But packaging tape may cause it to go along the surface of the water better. I did put a bit of tape on the bottom of the floats the first time I went flying and I managed 2 flights- but there was a strong wind however. But any why what do you think?
Old 05-08-2005, 07:32 AM
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akflyer
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Default RE: LT-40 on Floats-No go!

if the bottoms are rough, it creates a lot of drag. I use 3m 77 contact cement (sprat a scrap first and use a very light coat) on the foam then put on the tape when it is almost dry. I bet the bottoms are rough enough that you just cant get any speed up due to the drag....get them smoothed up and let us know how it goes.
Old 05-08-2005, 01:44 PM
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Default RE: LT-40 on Floats-No go!

Sounds about right.
Old 05-13-2005, 11:21 PM
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Default RE: LT-40 on Floats-No go!

Have you tried it again yet ??? Hoping it will fly now, just wondering how it went...
Old 07-14-2005, 10:28 PM
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Default RE: LT-40 on Floats-No go!

Please advise if a Supertigre G-34 will be enough power for a Kadet LT-25 equipped with floats ?

Thanks

Old 07-15-2005, 01:19 AM
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Default RE: LT-40 on Floats-No go!

I have gone off the idea of floats at this stage, however I brought a 10-5 prop instead of a 10-6 which should provide me with a bit more accelaration. I hope to try it another time and I will cover them with something or a thick paint, which as you said (akflyer) will reduce drag. Regarding the previous post, this is my thread on my LT-40 with floats, so you will probably get more coverage starting your own thread, sorry I can't help you but there will probably be some who can.
Old 07-15-2005, 01:22 AM
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Soloflyer!!!
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Default RE: LT-40 on Floats-No go!

You need quite a bit of power to float fly, what is the recomended range? What ever it is you should be at the top end of the range or a few more sizes up, Its fine once your airbourne put sucking off the surface requires alot of power.
Old 07-15-2005, 06:40 AM
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Default RE: LT-40 on Floats-No go!

a properly set up LT 25 will fly fine off the water. Just make sure the floats are properly sized, constructed and rigged.

As for Soloflyer, if you were running a 10X6 then try an 11X5 NOT a 10X5. If you go down in pitch and diameter, then you are loosing speed and pull. I would even try the APC funfly prop 12.25X3.75
Old 07-15-2005, 10:11 PM
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Default RE: LT-40 on Floats-No go!

The LT-40 is normally a great plane on floats, but I think 2 lb floats are a bit much when combined with a 40LA, especially when it is turning a tame prop.

My LT-40 has a Leo 46 (a knock-off of the old OS 46SF) turning either an 11x6 or a 10x7 APC prop. With floats the total weight is 7 lbs 12 oz. It came up off the water beautifully.

BUT: if Soloflyer's floats are not covered at all, there will be way too much drag from the rough foam surface. I scratch-built my floats from balsa, and put a thin fibreglass coat on top, painted with Krylon flat aluminum. Even with the step about 1.5 inches AHEAD of the CG (I screwed up the struts, gotta fix that), it came up on the step nicely. There are a couple of pix of my plane on an earlier thread in this forum if you want to see it.
Old 07-20-2005, 01:33 AM
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Default RE: LT-40 on Floats-No go!

Thanks for your help, I didn't know that about prop sizes and pitch, how much more pull would I notice with a 11:5? Cheers
Old 08-02-2005, 04:18 PM
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Default RE: LT-40 on Floats-No go!

iflyj3 What brand of floats do you have on your LT40 they look nice?
Britt
Old 08-02-2005, 07:22 PM
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Default RE: LT-40 on Floats-No go!


ORIGINAL: brittgo6

iflyj3 What brand of floats do you have on your LT40 they look nice?
Britt
They're home made from foam and were cut for me by a fellow modeler. I covered them with .6 oz fiberglass cloth painted on with water based polyurethane. I ran a 1/4 inch by 1/2 inch plywood back bone on top of the floats for hardware attachment and rigidity. At 5 equally spaced places I drilled a 1/4 inch hole and glued in a 1/4 inch dowel rod in to the foam.
Old 08-03-2005, 01:58 AM
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Default RE: LT-40 on Floats-No go!

I am woundering how you get the photo beside your username on the left hand side of the Post, does anyone know?
Old 11-13-2020, 11:53 AM
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I have a Tower Hobbies .40 high wing airplane. I have the floats, but need to know where the step should be in relation to the CG. Thanks John from Hesperia Mi
Old 11-13-2020, 01:44 PM
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Originally Posted by Captain John View Post
I have a Tower Hobbies .40 high wing airplane. I have the floats, but need to know where the step should be in relation to the CG. Thanks John from Hesperia Mi
The step is usually slightly before the CG. For a lot of float stuff see my site for the CKFF at https://sites.google.com/site/ckffinc/
Click on the links to obtain floats for a page of a lot of information. There are some magazine articles at the bottom of the page.
IIRC, the length of the floats should be 80% of the length of the fuselage as measured from back of the prop to the rudder post. Also the floats should stick out about 2 inches in front of the prop.

It is my experience that you need to up the power by at least the next size up in engine power. A .46 will probably work for you.
The water drag on floats is really great, especially on glass smooth water. An under powered float plane is a good air boat.
EDIT:
Some of the pages referenced on CKFF are no longer available. It has been years since I did that page and a lot of them have gone. I will edit the page and remove those that have gone.

Last edited by iflyj3; 11-13-2020 at 02:15 PM. Reason: corrections.

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