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Old Jun 15, 2005, 07:32 AM
gpw
“There’s no place like Foam”
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Foamie Flying Boat Design Group...

Seems like the flying boat is all the rage now , lots of folks begging for plans .... So why don't we make a list of the parameters and design a few of our OWN flying boats .... Let's learn what works and what doesn't ... and by combining our ideas/experience , we can develop a better looking/flying /building vehicle , schmaybe' even apply it to some full scale stuff.... wouldn't you want to pilot your own flying boat ????? We have the resources , just need to hear from you guys .... all ideas /designs gratefully accepted ...
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Old Jun 15, 2005, 07:38 AM
gpw
“There’s no place like Foam”
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First, I'd like to comment on the sponson design .... being an old boat guy from way back on the bayou , I really believe that slanting the botton surface outward and UPward would not only get the hull out of the water quicker , but would even add a small dihedral effect to the flying qualities ... a "stepped" sponson would be even better ... look at some real boats .... same thing ...
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Old Jun 15, 2005, 07:53 AM
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Glen: Is there an optimal amount for the "dihedral"? I'm thinking about 10° on each sponson myself.....I'm doing my own version 2.0 right now, but I'll hold off until there's an answer to this one...V2.0 will have an airfoil for the deck - gonna use ~2mm / 3/32" foam for the skin (I strip my own foam).

Brad
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Old Jun 15, 2005, 07:55 AM
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I agree with GPW.
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Old Jun 15, 2005, 08:00 AM
JAM
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I have Proper's boat printed out and ready to cut but maybe I can incorporate this into his. I'll look at the plans tonight and see what I can do to make some changes.

TM
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Old Jun 15, 2005, 08:03 AM
gpw
“There’s no place like Foam”
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A&S... There is always an optimal amount , but unfortunately , I don't know it , but I'll bet someone out there does and would be willing to disclose such an obviously secretive amount .... Meanwhile , back at the docks , we could try different things ... the principle is : as the sponson rides through the water , the faster it goes the higher the hull rises in the water , resulting in less "wetted-area" and therefore less DRAG , resulting in more speed , etc, and eventual take off .. That's the principle .... you can see a flat bottomed sponson has a flat wetted area that must drag across the water like a flat bottom boat ...
You can see why a stepped sponson is a better compromise ... the faster you go , boat hull rises one step at a time ... till...

I think we need to establish some proportions , to enable us to build bigger or smaller ones ( I have some old Astro cobalt motors which I wouldn't mind dunking ....) Like an aspect ratio .... 3/1 , 4/1 , the Biblical 6/1...????
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Old Jun 15, 2005, 08:06 AM
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Quote:
Originally Posted by gpw
I think we need to establish some proportions , to enable us to build bigger or smaller ones ( I have some old Astro cobalt motors which I wouldn't mind dunking ....) Like an aspect ratio .... 3/1 , 4/1 , the Biblical 6/1...????
Well, it looks like 1:1 for wing loading, or about 3:2 (L:W) if'n looks are more important....

Brad
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Old Jun 15, 2005, 08:20 AM
gpw
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A&S, Please explain .... I was thinking more graphic like this ...<> , < >, < >, < >...???? Hmmm that was vague .... how about considering the vessel/ aircraft is currently like three squares laid end to end , with the first square mostly missing (canard as planes see it ) ....
we know too long doesn't handle well (rolls too easy ) and too wide looks like a floating /flying picnic table .... so 1 square (1:1), 2 squares (2:1) , 3 squares (3:1)... sorry about being so anal about this ,I'm just trying to get on the same page with our "terms" ... Thanks !!!
Tow , try cutting 1/4"(or so ) off the outside sponson wall bottom so the bottom will rise towards the outside , that should work .... Please keep us posted as to the progress....
fork , thanks !!!
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Old Jun 15, 2005, 08:39 AM
and this wire goes where?
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I have no idea what a sponson is (sorry! ), so I may be way off mark, but I'm thinking you mean the bit that sticks into the water like twin boat hulls?!

If so, have a search about for info on "water aircraft floats" on google - I'll see if I can dig it back up later but a while back I found some very useful links n stuff on calculating the stepping etc.
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Old Jun 15, 2005, 08:45 AM
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sponson = "pontoon" I'm thinking if we're doing boats, we should probably use the right terms......then other people will think we know what the heck we're talking about

Brad
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Old Jun 15, 2005, 08:46 AM
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I was just thinking; there's no reason we have to limit ourselves to a tunnel hull type boat. What about an outrigger?

Brad
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Old Jun 15, 2005, 08:50 AM
and this wire goes where?
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LOL I've always failed when I try that approach, so I prefer to admit stupidity now

Only thoughts on the tunnel hull type is it's very easy to make it look like a boat rather than a plane, other designs will probably end up looking more like planes modified to go on water.

Just been having a look for that info on the stepping, cant find it here, might be at home though.
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Old Jun 15, 2005, 08:50 AM
gpw
“There’s no place like Foam”
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A&S,That would be a FIRST !!!!hahahahahaha
Dongle dingle dangle ole' biscuit barrell of Ulm , Sorry Eastleigh .... the outer bits that rest in the water and preceed the rest of the boat ... The real trick is making it look like neither boat ,nor plane .... what about that one ...???
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Old Jun 15, 2005, 08:53 AM
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Ailerons on the outriggers??? Hmmmm....


Brad
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Old Jun 15, 2005, 08:56 AM
gpw
“There’s no place like Foam”
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I think we should keep it simple at first , before we go creative....
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