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cyclops2
10-04-2006, 10:46 PM
I need to use (6) 400 brushed motors on her.-- 1 ESC.-- (1) 6 cell 3100mah nimh car pack weighs 13 oz..

What props, will give the maximum thrust to break loose from the surface.
What wing span will give 16 oz. / sq. ft. ?

Construction will be proven solid blue foam parts partially hollowed out to make the 1 lb. / sq. ft.

Thanks.

TLyttle
10-05-2006, 02:29 AM
Best of luck! A truly impressive project. Are you using geard or direct drive 400s? Either way, just follow the usual recommendations for that system.

Quite a lot of problems with "liftoff" has to do with hull design and surface smoothness, not power.

cyclops2
10-05-2006, 03:03 AM
Is there a good, proven shape for a flying boat hull? How many degrees of V ?

Where would the step be in relation to the C O G ?

Thanks.

Bill G
03-27-2007, 06:43 AM
Cyclops, its Bill the guy that sent you the batteries.
A few years back, there was an article with a seaplane that I believe was called a Puddle Master. I remember it was yellow, and I think it had 8 speed 400 motors. Have you seen it before?

I think the most important part of getting off the water is where the "step" in the hull is located. When the plane actually takes off, they are planed out pretty well, and most of the hull is out of the water, other than the flatter area by the step. There probably is some degree figure for this part of the hull, which seems to be pretty similar on most boats. The front area with the steep V is only in the water at below planing speeds, where the shape is important in low speed displacement hulls.

Bill

TLyttle
03-28-2007, 02:13 AM
Over the last 50 or more years, I have seen all forms of theories applied to this problem, all by qualified experts.

In the 50s (the day of the "long-planing hull") the step was ahead of the c/g. In the 70s, it went behind the c/g. The step was vee'd. It was flat. It was inverted vee. Departure angle had a 20deg spread over the years. The only constant is the lack of consensus!

Pick one...

Bill G
03-28-2007, 05:36 AM
Give it enough power and anything will take off.:D

LADISLAV
03-28-2007, 09:37 PM
I am not sure if Cyclops is still interested in building his model, but my experience with the scale seaplanes is - stick with the original set up. One of them was my 80” Potez Cams 161. Mine had six 6V SPEED 400 motors.
Laddie.

cyclops2
03-29-2007, 12:38 AM
I loved TLyttle's Historical Information !:)

Try it all. Ploughing a boat hull up to planing speed with a deep V type of hull takes loads of horsepower compared to a flatbottom boat.

I may cheat on the 6 engined boat and put a clear plastic flatbottom on it to help it get up in less than 150'. Martin Clipper needs that on calm water. Takes so much power that it leaves only time for 1 big circle and down for the landing. W O T all the time. I use NIMH for safety reasons.


Hi Bill. I get wrapped into to so many projects that I read very little now. I am sanding a 60" Avro Vulcan wing. 1 1/2" thick pink foam, 1 piece. GWS ..A-10 just arrived. WAAAHOOO!!:) :) :) I love the Hog planes.

Bill G
04-08-2007, 06:11 PM
I loved TLyttle's Historical Information !:)

Try it all. Ploughing a boat hull up to planing speed with a deep V type of hull takes loads of horsepower compared to a flatbottom boat.

I may cheat on the 6 engined boat and put a clear plastic flatbottom on it to help it get up in less than 150'. Martin Clipper needs that on calm water. Takes so much power that it leaves only time for 1 big circle and down for the landing. W O T all the time. I use NIMH for safety reasons.


Hi Bill. I get wrapped into to so many projects that I read very little now. I am sanding a 60" Avro Vulcan wing. 1 1/2" thick pink foam, 1 piece. GWS ..A-10 just arrived. WAAAHOOO!!:) :) :) I love the Hog planes.
I hope my Seabee doesn't need ridiculous power to get off the water. The hull is not too deep, but the tail wheel will drag a bit, even when retracted, until it really planes out. Hopefully it can, without spending more loot on a motor. I could steal one from another plane, but I've vowed to quit doing that.:D The setup I have now should peak at 300W for 20 sec, per spec, and spin a 9070 3-blade at close to 10,000 rpm.

I finally took out the brushed EDF50 fans in my Hog and installed Microfans. Need to try it out when the weather gets better. Here's what I did for the gear:
http://www.rcgroups.com/forums/showthread.php?t=365381

Oh, that's right, this is seaplanes.:eek: