PDA

View Full Version : My General Guidelines for waterplanes/seaplanes


GreenAce92
12-05-2010, 09:17 AM
Hello Ladies and Gentlemen, I am the Green Ace of the skies, crashing and building and crashing and building as I go, I record my data collected from my feats and failures...

Here's one now

Getting a waterplane design out of the water.

The most important thing about a waterplane is it's step. If you look at any flying boat or seaplane with pontoons, you'll notice that at the bottom of the said 'hull' there are little steps, they look pretty sharp.

Basically the purpose of these steps is to break the suction created from your plane and the water. Once this "suction" is broken your plane is free to climb after lifting off from the water.

Another key important aspect to note is the center of gravity.
In most seaplane/waterplane designs, the CG is positioned between .5-1in ahead of the so called 'step'.

Likewise, the Angle of attack of the wing in relation to your engine's central axis line also matters.

In a puller configuration, the motor will be angled upwards (due to the lever-like forces exerted on the plane by the motor) with the motor angled upwards, the wings angle of attack in relation to the horizontal line of the plane will also be angled upwards.

This is for a water plane ie flying boat

On a piper cub with floats for example, the floats will be mounted with the front end of the floats lower than the rear, this gives the floats a negative angle of attack, how much exactly? I don't know however, with this downwards angle, this will provide you with the positive angle of attack on your wings when the plane is floating in the water.

Going back to the flying boats, pusher configurations differ in a way but they too are angled upwards to compensate for the lever-like force that the motor exerts on the plane

Also it is important to have wingtip pontoons on flying boats, these pontoons should have a high angle of attack that way if the wing does strike the water, the pontoon will cause the wing to merely bounce off the water and the plane should keep going

....will finish with diagrams

sources
http://www.youtube.com/watch?v=_bfiJnGjKK0
my own scratchbuild flying boat custom

CHELLIE
12-05-2010, 09:38 AM
Good job on the Sea Plane :) add a little water rudder under your rudder, just add a little below it, that will help a lot on the water, also, Give your planes MORE POWER :D Your not a beginner anymore :Q Take care and have fun, Chellie


BTW, Where have you been Hidding at ???? :D LOL

Jim Casey
12-05-2010, 01:57 PM
Good stuff, Green Ace. Your data corresponds with published guidelines such as the Chuck Cunningham article (here, and in other places:http://flyinglindy.homestead.com/skisandfloats.html)
Also with specifics for flying boats or monofloats (including tip-float parameters) look here:http://www.smilesandwags.com/Floatsite/westwood.html
And a great overall article by Ironsides in Canada: http://www.smilesandwags.com/Floatsite/THE%20BASICS%20OF%20FLOAT%20FLYING.docx

I like the Cheesepuff. If I built one I would be tempted to paint it "Cheetos Orange".

flyingbumma
12-05-2010, 06:08 PM
Great info.

GreenAce92
12-06-2010, 01:39 AM
Haha cheetos orange
Yeah indeed that would be great, I almost never paint/design my aircraft

hi chellie, been hiding at RcG it's hard to keep track of two forums
I just felt like I "abandoned" you folks so I thought I should get back to the place where it all started

SHADY
12-06-2010, 02:52 PM
Nice...