costum_truggy

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i'm trying to build an airboat that is going to be powered by a 30cc mccullock with a 10x7 pusher prop. my hull is 34" long 21"wide at the top and 14" wide at the bottom. my frames are made out of 7/16th ply and the bottom is goin to be 1/16 ply. i just dont know if it is going to work good. if anyone has done anything like this and has any advise give it to me. i dont like putting money into things that are not going to work. this is my first airboat build.

costum_truggy

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the prop is going to be a 3 blade.

crispyspa

30 cc WHAT? Weedeater or chainsaw? At 30cc...it's probably a chainsaw, in which case you will need a tractor propeller for a pusher style boat, not the pusher. Use the pusher if you are building a puller style boat.

I just confused the snot out of a whole bunch of people. [&:]

greygoose81

crispy is right, knowing what the 30cc was made for is a big deal. if its a chainsaw you will more than likey have to start it with a drill or a starter. if its off a weedeater that has the pull start on the back, you got your self the perfected gasser airboat engine. we use a 14 three blade prop on our 27cc engines. take your time and ask question and you will not waste your money. this is a fun hobby. good luck.

kersplat

a 10X7 is waaaay too small for this McCullough engine. The RPM with this prop will be way outside the max HP sweet spot. [X(]Use a16 inch prop.

crispyspa

Oops, I missed that.

costum_truggy

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thanks. the engine is off a weedeater. i'm not worried about the engine mounts and all. i really just need to know if my boat frame is going to hold up. i dont want it to be to small and sink or just always flipping over. i think that i'm going to glass the bottom and sides though. i have some left over from my truggy body build. you said a 16" prop like a 16x7?

crispyspa

I think the closest you are going to come in a 3 blade pusher for that engine is something like 14 x 7....the next size up for a pusher 3 blade is 16 x 10 which would be too big.


check out [link=http://www3.towerhobbies.com/cgi-bin/WTI0095P?FVSEARCH=pusher+prop&search=Go]tower hobbies.[/link]

costum_truggy

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yea i think that ill try the 14x7. and ill see what the hobby shop has next to where i live. thank you all for your help

greygoose81

i use master airscrew. i think that is your only option for a three blade 14

kersplat

That is a 16" Two blade prop or a 14" Three blade. Remember a Two blade screw will blow a bigger gale than a Three blade. Any prop with more than Two blades will be less efficient. Believe me, you can use a small prop at a high RPM and make lots of noise, or you can swing a larger diameter and really haul the freight. I've tried different combinations on my Dumas Big Swamp buggy and the big Two blade props win out every time.

costum_truggy

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i have started to built my boat and ill put some pics on here when im done. also ill posts the plans if it works!!!

greygoose81

are you going to put a cage on your boat? and if so what are you going to use?

costum_truggy

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yea i am. i dont know i'm thinking about getting some small aluminium tubing or small steel round stock.

DONS BOAT WORKS

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My aluminium cage.

bayward

What do you use to weld these cages ? Nice looking cages BTW.

Bob

DONS BOAT WORKS

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I used aluminum solder.
http://www.alumiweld.com/

Don M.

costum_truggy

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yea you can get that stuff at home depot too. you just have to love for it.

crispyspa

I hope they don't require too much love....LOL

costum_truggy

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sorry LOOK for it. lol. here are some pics of what i got. the bottom of the engine is 8 1/2 inches from the bottom of the boat. i have a 14" piece of wood on the shaft. what do you all think. it looks too tall!!! i dont want this thing to roll over when i turn.

costum_truggy

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the prop that im going to be running is a 14" 3-blade. and im going to cut the stern so i can lower the engine a little like crispyspa did in another post he showed.

crispyspa

It doesn't look like 34" long in the pic. Could be an optical illusion. The math works out: 34 length and 14 wide at the bottom = 242% l-w ratio.....yet somehow it just doesn't look right. [&:] it looks way too short.

costum_truggy

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yea i know. to me it looks to tall. but i'll just build it and see what happens.

crispyspa

That's pretty much how we all started out.

costum_truggy

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hey guys,
i'm back ive been trying to get my boat up and running but its just not working out the way that i want it to. does anyone have any plans that i can use to make this airboat work good. ive tried a few different things and none of them have worked right. i went it to go fast and handle good. i will need pics and measurements and material list. please guys help me out!!!!! i want to build one!!!!!

thanks for all your help