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View Full Version : Questions for a Boat hull type seaplane


GreenAce92
08-12-2008, 06:07 AM
After looking at the thread about people's seaplanes, im droolin lol so i would like to try a scratchbuilt simple sea plane where the motor would be mounted on the wing and the wing will be held above the plane by skewer sticks. Anyways i need help understanding the step part, is the Step behind the CG or ahead of it if the plane is a puller? Plus could you guys give any general tips to help save me from a couple of encounters with the water?

thanks.

GreenAce92
08-12-2008, 06:49 AM
Any help at all? lol

Larry3215
08-12-2008, 07:26 AM
The step should be right at the cg. A hair in front or behind is no big deal on most planes if they are light enough.

Figure out the CG of the wing your going to build, then put it right over the step. Doesnt matter if its pusher or puller - the step and cg will be the same either way.

The only thing that will change if its pusher or puller will be the motor thrust line angles. Id do a puller. Its easier to set the angles by guessing :)

With a motor mounted up hi, Id start with zero up/down thrust, BUT you may actually need some UP thrust, so leave that adjustable if possible. A little right thrust is always good.

Make sure the nose of the boat portion sticks out well past the prop line.

Keep all the edges of the floats/hull that are in contact with the water sharp. Dont be tempted to round them off so they look purdy - its the wrong thing to do.

A simple flat bottom on the boat part will work fine. Other wise try a shallow V hull that isnt too deep a V but keep the edges sharp.

You dont want a deep V hull. You need to get up on top of the water as fast as possible - not cut thru it. Too much drag that way.

Look at pictures of similar planes and do what they did. There are almost always good reasons for doing things the way they did it :D

Water planes need more power to take off than ones that take off from the ground so allow for that.

Larry3215
08-12-2008, 07:29 AM
Forgot the most important tips -

1)water proof your esc and rx with CorrosionX. You WILL end up up-side down at some point. We all do!

2) Have a recovery boat or plan in place and ready to go BEFORE you try flying off the water. See #1 :D

GreenAce92
08-12-2008, 07:52 AM
Corossion X? where do i get this matter from? ;)
i was just plannin on wrapping my stuff in some sort of a ziploc bag. Then waterproofing the plane itself. Thanks for the tips on the floats, im building a single engine PBY Catalina kinda plane. Ive already built 2 but they werent the sea versions. Im planning on her being just a rudder/elevator plane soon as i get floats down then ill add flaps/ailerons and what not.

Larry3215
08-12-2008, 08:19 AM
You can get CorrosionX at most Ace hardware stores, Marine supply stores or aviation supply stores.

See post #3 in my Capricorn thread for details.

http://www.wattflyer.com/forums/showthread.php?t=26120

Trust me - baggies wont cut it :)

CHELLIE
08-12-2008, 08:50 AM
Hi GreenAce :) you Just Got the best Info ever, from one of the best of the best on wattflyers, where do you think I Get My Info from :D Larry is Sharp, if you get a chance, visit some of his Threads, he has some really neet flying hydros & Planes, Take care you Rascal, Chellie

PS its Past your bed time :)

jimsp
08-12-2008, 04:12 PM
From my experience with seaplanes the step location relative to CG isn’t super critical but I do prefer the cg to be at or somewhat ahead of the step. I would make the step about ˝” high. I would stick with a flat bottom hull because they are simpler to build and are faster and easier to get on step. The flat area ahead of the step should be at about a 3 deg angle. Angle the sides slightly and keep all edges on the bottom of the hull sharp.

For simplicity I’ve been mounting the floats to the hull instead of the wing. Like the hull, I think flat bottom floats work best.

The pylon mounted motor will probably need some up thrust. This of course will vary with the particular design but mine have been in the 6-8 deg range. You should design the mount so you can experiment with this angle. I wouldn’t try a test flight without some up thrust as the plane may want to dive not climb as power is applied. From experience I can tell you this can be very disconcerting.

GreenAce92
08-12-2008, 06:03 PM
Yeah im just worried about destroying my electronics i dont mind going for a swim lol. I think i will go with a V hull a shallow V i like the better loooks and a good challenge too. But umm yeah ill keep it shallow sharp edges. Oh yeah a guy told me that on pushers the Step is behind the CG. Is that right?

GreenAce92
08-12-2008, 06:15 PM
So you guys are saying if i just spray this Stuff on then i can dunk my electronics in the drink and nothin will happen?

By jove i think i can do submarines again lol

I think home depot will have it.

Hey larry at the beginning of the third video on your first post, what you were doing would you concider those donuts? ;)

FlyingMonkey
08-12-2008, 06:17 PM
For any of this, try to picture what the feature is for. In this case, the step, what does it do?

It allows the plane to lift some of it's weight off the water, while still maintaining enough contact to keep the plane balanced until it lifts off. At the same time, it's a way to reduce the connection to the water that surface tension creates. So, in theory, it should be the last part of the float that touches the water. Seems like it should be right at the cg.

FlyingMonkey
08-12-2008, 06:18 PM
So you guys are saying if i just spray this Stuff on then i can dunk my electronics in the drink and nothin will happen?

By jove i think i can do submarines again lol

I think home depot will have it.

Hey larry at the beginning of the third video on your first post, what you were doing would you concider those donuts? ;)

actually, somewhere on here, (or on the "other forum...) there was a write up on how to properly use Corrosion X. Essentially it was said you dunk your electronics in the stuff. There was a bit more to it than that, but the gist of it was submersion was required.

GreenAce92
08-12-2008, 06:25 PM
If my stuff dies Larry owes me a new one lol. Ill do what he said on post #3 im a cheap man and if my stuff dies i definitely wont be flying for alot longer. Right now im waiting on my props to get in.

FlyingMonkey
08-12-2008, 06:30 PM
If my stuff dies Larry owes me a new one lol. Ill do what he said on post #3 im a cheap man and if my stuff dies i definitely wont be flying for alot longer. Right now im waiting on my props to get in.

You can't afford to be cheap...

I know much of your stuff is donated. It would be rude to not take as good care of it as you can. Senselessly throwing away electronics is a sure way to not get any more gifts.

GreenAce92
08-12-2008, 06:33 PM
Oh i havent "senselessly" thrown away my stuff did you know i havent bought any electronics except rx's? ive used the same ESC chellie sent me the same motors. Ive still got all of it allthough the 2409-12's are dying(wires are coming off of stators) but yeah i havent bought anything at all yet ive been using what people have given me so no i havent been senselessly throwin stuff or destroying stuff just because its given to me.

Although i do have to apologize to mike cuz i broke the shaft on the Park 480 for using a gas prop on it. But at least i wasnt straining the motor as i was only running it at like 8 or 9volts. So it was cold the entire time but i'll replace the shaft soon.

Dont worry i plan on returning the favor someday.

FlyingMonkey
08-12-2008, 06:47 PM
but yeah i havent bought anything at all yet ive been using what people have given me so no i havent been senselessly throwin stuff or destroying stuff just because its given to me.

I am just saying, to take the least amount of precautions, while putting your electronics at the highest possible risk, isn't showing the respect that the generosity you have received deserves.

I can say from experience, electronics will fry in water. Holding my plane up, in front of a body of water, just to see what it looks like is almost enough.

No matter how well I thought it secured, how well sealed I thought I had the electronics, how little moisture I thought reached the internals of the plane, it didn't matter, the ESC's die out of spite.

GreenAce92
08-12-2008, 06:53 PM
Well i said i was going to try the Corrosion X stuff then put it in a baggie of some sort plus waterproof the body of the plane itself. Im really worried about this too because its my only working receiver and esc right now. Plus my only lipo battery. Im kinda thinking of just makin the seaplane but not putting it in the pond at all because i cant fly out of there anyways because its surrrounded by trees.

Larry3215
08-14-2008, 03:38 AM
If my stuff dies Larry owes me a new one lol. Ill do what he said on post #3 im a cheap man and if my stuff dies i definitely wont be flying for alot longer. Right now im waiting on my props to get in.

Not to worry. All my advice comes with an unconditional 10000% money back guarantee.

If you are dissatisfied with my advice or if it causes you undue financial loss, harm, trouble, problems, lack of sleep, apnia, gas, diarrhea, indigestion, dyspepsia, malaise, hair loss, ingrown toenails, ablepsy, ague, biliousness,pox, bule, catarrahl, bad luck, pimples, runny nose or misfortune in any way what so ever.....

Just return the unused portion in the original container and I will refund you 1,000 times your purchase price - guaranteed!

Heck, I'll even pay the return shipping! :D

GreenAce92
08-14-2008, 03:44 AM
I dont know its ok man, if i do get it wet and broke then i guess its my fault. Ahh i was thinking of starting with something simple anyways since i have a low kv motor i was thinking of building a bushplane of some sort then having it on wheels first, after its proven to fly well then i'd build some flat bottom floats. Guy posted pics of his mod'd slowstick on one of my threads and i liked his silver flat bottom floats pretty neat.

CHELLIE
08-14-2008, 04:43 AM
Not to worry. All my advice comes with an unconditional 10000% money back guarantee.

If you are dissatisfied with my advice or if it causes you undue financial loss, harm, trouble, problems, lack of sleep, apnia, gas, diarrhea, indigestion, dyspepsia, malaise, hair loss, ingrown toenails, ablepsy, ague, biliousness,pox, bule, catarrahl, bad luck, pimples, runny nose or misfortune in any way what so ever.....

Just return the unused portion in the original container and I will refund you 1,000 times your purchase price - guaranteed!

Heck, I'll even pay the return shipping! :D


THATS FUNNY :Q :D ;-)



I like BUFY :$ You Have got to see her with PINK FLOATS :p>



http://www.wattflyer.com/forums/attachment.php?attachmentid=63438&d=1208729649



BUFY wins wet teeshirt contest!
I made it out to the pond with Paul and got some "wet" video :D

Water handling is just fine.

The floats are on the heavy side though, so Im going to build a new set and try to keep them a lot lighter.

This size and shape seems to work well though.

Larry

http://www.youtube.com/watch?v=36mGKTsmesg&eurl=http://www.wattflyer.com/forums/showthread.php?t=29624&highlight=bufy&page=5



Attached Thumbnailshttp://www.wattflyer.com/forums/attachment.php?attachmentid=63457&stc=1&thumb=1&d=1208740797 (http://www.wattflyer.com/forums/attachment.php?attachmentid=63457&d=1208740797) http://www.wattflyer.com/forums/attachment.php?attachmentid=63458&stc=1&thumb=1&d=1208740797 (http://www.wattflyer.com/forums/attachment.php?attachmentid=63458&d=1208740797) http://www.wattflyer.com/forums/attachment.php?attachmentid=63459&stc=1&thumb=1&d=1208740797 (http://www.wattflyer.com/forums/attachment.php?attachmentid=63459&d=1208740797) http://www.wattflyer.com/forums/attachment.php?attachmentid=63460&stc=1&thumb=1&d=1208740797 (http://www.wattflyer.com/forums/attachment.php?attachmentid=63460&d=1208740797) http://www.wattflyer.com/forums/attachment.php?attachmentid=63461&stc=1&thumb=1&d=1208740797 (http://www.wattflyer.com/forums/attachment.php?attachmentid=63461&d=1208740797)

GreenAce92
08-14-2008, 04:57 AM
Wow that looks hot! lol nice i use to build flying wings from that stuff good stuff. So whose bird is it? is it yours Chell'?

Well whatever i do i gotta put floats on this bad boy when i get her built up. Im thinking of a single float in the middle though and some pod booms on the wings.

FlyingMonkey
08-14-2008, 05:05 AM
you need to look up the Schneider Trophy

CHELLIE
08-14-2008, 05:05 AM
Wow that looks hot! lol nice i use to build flying wings from that stuff good stuff. So whose bird is it? is it yours Chell'?

Well whatever i do i gotta put floats on this bad boy when i get her built up. Im thinking of a single float in the middle though and some pod booms on the wings.

Thats Larrys BUFY , Looks neet huh :D

GreenAce92
08-14-2008, 05:09 AM
Heck yess!! thats a massive rudder lol.

Oh hey FM i think i know what your talkin about well i dont know i also got inspired from the Supermarine Floatplane.

FlyingMonkey
08-14-2008, 12:38 PM
there's so many planes to get inspiration from, do a google search, you'll have plenty of material.