Why was my boat upside down in the water?

[lmopar69]

Ok, I built an V-hull air boat last night/this afternoon (about 2 1/2 hours) from fan fold foam. I took it out with a S400, 5x5 prop, and a 3S lipo. Couldnt really get out of its own way.

So, why not slap on a Typhoon 3W, 5x5 prop, pheonix 35 and a 3S 2P 4200 lipo. Ok, NOW its a stinkin fast. The only problem now, is what in the world did I do wrong that caused it to flip upside down in a "mid-speed" (1/2 throttle) turn?

Is the design THAT bad? What do I need to do to fix this thing? Trash it? Stick with airplanes and helis? Any thoughts? Hopefully I didnt just smoke $400+ worth of electronics by dunking them!

Oh, and no, the motor is not mounted with rubber bands, they are there just in case the mount fails to help keep the motor from launching itself.

[LtDoc]

Off hand, I'd say your boat was top heavy, center of gravity too high. Or, caught some air under the bow and flipped. Just from the looks of it, I'd have to go with the top heavy thingy...
- 'Doc

[lmopar69]

The only weight thats up high is the motor itslef though. And with that big 3S 2P 4200 lipo in there real low (lipo is not in the pic), that certainly should make up for the motor weight dont ya think?

Do you think I need to put a fin or something on the bottom to help keep it in the water? Would that even help?

[Aerominded]

Hummm, being foam, I would guess that hull is very light- extra weight would solve your problem (and I guess you could argue that having a rightside up boat is on average, faster than an upside down, light boat!) but would not be innovative- I wonder how a set of ailerons, mounted in the propwash would work? :) wonder if they would be effective enough in roll to at least keep the boat level in turns? could be a fun experiment! whatever you do, don't give up on boats! they are great for when there is too much wind to fly! :cool:

re the electronics, I have heard of a lot of seaplanes having mishaps with similar equipment aboard that lived to tell the tale! ;)

[boatman1]

Theres 2 things i can say without seeing it run is a problem
1 is the side angles need to be like this \______/ on the
back third of the hull , not what you have <____>
2 the hull is probally way to light over all & the back third needs to be flatten out
some like a real boat is
if it was me id try to shave the back 6 inches off th v point to give it a flat spot & give it another try & see what happens
good luck

[Treetop]

I think the boat is confused about which side is supposed to be up. :D

Why isn't this in scale forum?

Imopar, I think you will like the FFF S. S. Olive, he used 12 bricks for ballast:

http://www.rcgroups.com/forums/showthread.php?t=412803&highlight=theodore+

[lmopar69]

That S.S. Olive is cool! Thats a lot of FFF!!! And 12 Bricks! Dang!

I gave the boat a stern talking to last night after the event. So, it should no longer be confused about "upside down and right side up". Dang boats never listen do they.

As far as my little project goes, I think everything is dried out now, a little hair dryer and sunshine helps. Im going to take it back out to the water this morning, do some low to mid speed running and see if I can tell what is happening.

It was dark last night when it flipped over, we were using a spot light and my truck headlights to see. So, I wasnt able to tell for sure what the cause was. I do know it flipped over INSTANTLY with a hit of throttle in a full rudder turn. I mean, there was NO DELAY at all, it just went ZING and was upside down. Which tells me, as you all have said, maybe it needs some more weight in the nose, and it needs to have the bottom flat at the back end. I figured to be able to turn I would need the "V" at the rear end also.

The wife is making fun of me, wondering how long it will be before I try to mount wings on it and make it fly. I dont need no stinkin "hydro foam" though. But, it might be cool... Nah.

Thanks for the help!

[Treetop]

I gave the boat a stern talking to last night . . . - Imopar

HA! :D

I especially like the use of hose washers for portholes and bubble pipes for vents on the S. S. Olive, and always loved Popeye and Wimpy as a kid.

Please sir, could I pay you tuesday for a hamburger today?

[lmopar69]

Well, success! I put regular rudders on the bottoms of the "air rudders" Plus I put to small (1/2" tall) fins in the center on the bottom. Now its slower, but, I can run full out strait or in turns and it stays shiney side up. Turns on a dime too!

[Treetop]

More pics!

How about some lights for the night runs. Kind of looks like a gator taking boat, on the sly, so maybe lights wouldn't be a good idea. Good for fast getaways!

[lmopar69]

I'll post a couple more pics in a little bit.

[lmopar69]

Here are a couple more pics of it. I have a video, but so far I dont have enough space left on here to post it. I will delete some old stuff and get it posted soon.

[lmopar69]

Video is before the fins were put on underneath and before the "water rudders" were installed. Here is a link to the video...http://www.rcgroups.com/forums/showthread.php?t=504960#post5329991

[Elroy68]

not much.

[Elroy68]

not much.

[Treetop]

Man, that water was so calm in the video. Now what are tadpoles for???? :)

[Elroy68]

Not much.

[lmopar69]

Man, that water was so calm in the video. Now what are tadpoles for???? :)

I have been informed elsewhere that tadpoles (he called the catapults first) cause little boys to get muddy.

I think the boat works out pretty good now. I put the submerged rudders on and it slowed it down quite a bit. Made it much more stable too.

As far as a S480... well, if your talking brushed, that would be slower than this 3W brushless wouldnt it? I do have a "Chili Pepper 50" brushless I was going to put on it... I think that might be overkill.

[lmopar69]

Impoar69- your cg could move forward about a 1". you know being that light, a race 480 at 27,000rpm would be a sight to see. You know that would make a good rainy day project, got any plans? I can see a future for something like that cause of economics and average JOE can do one just to have fun!


Plans... hmmm, somthing Im not familiar with! :D I just get ideas and build stuff and see what happens pretty much. I dont think you would want any plans that I drew up anyway lol.

[9LIVES1968]

Laine,now all you need to do is fiberglass with polycrylic and paint it or econocote it to give it some color.How about Camo?lol.I have some red,white and blue that we culd throw on in about a half hour when you come up.BTW,your plane is a carl goldburg 300.Look at my thread inder fuel planes.Your boat is pretty cool.I would have never come up with that design.Dave

[lmopar69]

I have some silver solite left over I may slap on the thing. You know, rednecks like shiney stuff and this is the heart of the south.

I'll check the thread on the 300. See ya tomorow.

[Shaun Hendricks]

The commentary from the S/O was the funniest thing in the video! LOL! :D

[lmopar69]

I agree Shaun... I wish now I hadnt edited it all of it. You missed most of the times he called the tadpoles catapults. Kids are cute. Here is what he was looking at. He made mom take a picture of the "Catapults"

[Treetop]

You know, rednecks like shiney stuff and this is the heart of the south. - Laine

Hey!!! We like primer, but not just one color of primer, must use at least two. Red and grey is good. Some tabakky stains on the drivers side wouldn't hurt either. :D

[wingnut163]

just watched the vid, i bet if you put steps on the back with a slight down tilt it would kep the noes down and it might even plane. other than tat she looks ok abd runs well.

[lmopar69]

Your saying build up the back, flatter like has been said before? To "lift" it more up on plane? Im guessin the "V" is slowing it down quite a bit. I been trying to come up with a way to do it and I think I have an idea, without getting too crazy tearing it all apart.