500 lb. koolaid man

- hull: 3/8" plywood -dimensions: 24"x15"x2"
- .40 magnum gp with aluminum prop spinner nut and 10x6 master airscrew puller prop
- seamless 6oz fuel tank
- futaba 4yf radio system
- also made motor mounts this weekend out of 1.5"x1/8" aluminum, 1/2" clearance to ground, no holes drilled yet
- I plan to make an interior radio box out of the 3/8" wood and a plexiglas top. I also plan on making a duel rudder system soon.



This is my first homemade boat. I almost finished with the hull, and now realize that the wood should have probably been thinner, but oh well. I have slowly been working on this boat since around Christmas time. The boat does not have the top glued on yet, I have more to do before that happens. I originally got the dimensions for the boat from the Cajun Gator Jr, since it's a .40 flat bottom air boat. It will either be glassed or hopefully theres a cheaper way I will discover to seal it. It will be run in mainly salt water, and occasionally fresh water.

Any comments and suggestions are welcomed.

rickburnout666

Its looking good, are there any supports in the hull for the decking? just use epoxy resin over the wood sections that will keep it water and fuel proofed, maybe just glass the joins on the inside

500 lb. koolaid man

I am going to put two stringers in the hull running from the bow to the stern as support.

2 questions for you:

- Will the resin seal up all the joints with water soluble wood glue along with the wood?

- By epoxy resin, do you mean fiberglass resin?

thanks

rickburnout666

you can use poly(fiberglass) resin but that stinks and has nasty fumes, so a lot of peopl use epoxy resin but it`s a bit more expensive(here in the UK) i`m not 100% sure on the water soluble wood glue, the wood glue i use is water resistant, im using it on my balsa airboat build, and then using epoxy resin, to seal the wood and make a harder surface for the soft balsa, its alredy got dents and i aint finished building []

boatman11

i did the same thing with my boat i made a tank not a boat idont think a bullet could go through mine!!!!!!!!!!!!!!!!!!!!jk

500 lb. koolaid man

I was not completely sure about what would happen to my glue if it was exposed to water, so I tested it. I tested how my glue (a completely dry blob) reacts to water. It instantly broke down.

I just looked at my glue bottle and it says "water cleanup" on the back[:'(] not the best glue to use I guess Hopefully resin or epoxy will make this issue irrelevant.

crispyspa

Use thick ca (superglue) to glue the hull. very strong and water won't effect it. Or you could use "Gorilla" glue http://www.gorillaglue.com/home.htm

vamp131

Wow looks fantastic remember to got to angel the engine i made that mistake lol

it wanted to be a submarine lol changed the angle its great front of the boat go,s way up lol

500 lb. koolaid man

Thanks for the compliment

I think I just might be in luck when it comes to the engine being at an angle. When both of the mounts were made, amazingly, they were both made with a very slight yet visible angle at the engine attaching side. The two stands line up perfect. Since they line up perfect, I can turn them around to have the engine's offset up or down. Which way does it need to be, pushing the air slightly more toward the sky or toward the water?

Thanks

saleens7

towards the sky....it lifts the bow slightly (less chance of diving) and it somewhat counteracts the force of the prop trying to keep the bow down....

if you had the air pushing at the water, you might be running with only the nose in the water at WOT

mrfixitwhite

hi looking good so far!
3/8" ply you say- gonna have some weight to it then?
Slower till it gets moving ....then once its skipping on the water -you try stopping it!! hehe GR8 fun!!
only one thing is the square sides- you may get a tipping action on corners if they dig in - so just be prepared.
but straight line speed should be good
hopefully see it on the water soon

p.s you can always change the angle of the engine with a washer under the front or back mounting holes

Graham

500 lb. koolaid man

I decided that since pullers seem more efficient, its gonna be a puller.

I need some help. How far from the transom or bow should the motor be? The boat's 24" long.

What should the dimensions of my rudders be(thickness, hight, width)? I want to make a homemade pair out of aluminum, simple rectangles.

Thanks!

500 lb. koolaid man

I'm thinking for the rudders 1/16" thick aluminum, 8" tall ( the prop is 10" ) and the width will be 1.5". Sound good?
I don't know much about r/c airboats so I would also like to please know where the engine should be mounted for good performance.

Thanks

rickburnout666

I know aluminium is light, but ABS or fibergass would be lighter still, And i would use rudders as big as the prop, the width is ok
Sorry i cant help on where to put your engine as i have built flat bottomed airboats before and they all had the engines different distances from the transom, because the boats where different and set ups were different , you could make a movable mount, so you could adjust it and get the ride/handeling right

saleens7

if its going to be a puller, i would put the engine somewhat close to the transom...you can always adjust the CoG by with the placement of the radio box....i would try to make the CoG a little bit further back than what it would be on a water propped boat (maybe 20-28%)....this is because the the prop will want to push the bow down, where with water propped boats, its placment would want to push the bow up....you can see what i mean when you look at a water propped boat when its accelerating, the bow will lift up and the back end will push down in the water...

500 lb. koolaid man

Thanks for the help guys. I will try to make time for the boat this weekend and post any progress.

itsmiller

i love the look of this hull,,,where can i get specs to make a similar hull for my first airboat?? im not sure of a pusher or puller,,what are the pros and cons?? im using a thundertiger pro 46 gas plane engine.....with a 10x6 prop,,,,,

rickburnout666

put plans into the search , this question gets asked a lot, there are plan links in the threads. My advise is , go with a puller prop set up there are more choices,

500 lb. koolaid man

if you want to build this hull, thats a very simple task. I did not use plans. In order to try and get ok performance I took the dimensions of the cajun gator junior http://cajungatorairboats.com/page2.html (except mine is 2" shorter) at 24" X 15" X 2". I used 3/8" wood which is probably thicker than most would use, and simply cut the pieces and glued them using wood glue. Sorry, I cant remember the degree of the bow. I want to get back to this build soon, but like a lot of us here, I have many many projects going at once. Your .46 would work just as well if not better than my .40 IMO. A puller is the best way to go from what I have heard because the main thing is it keeps the engine running cooler than a pusher, just like majority of the r/c planes. The only problem with my air boat hull is it might grip in the turns and possibly flip or something because the sides of the boat are 90 degrees. If you have a lot of time to build an air boat, (I am considering building this in the future) I would recommend this. http://cajungatorairboats.com/v-web/...dd1f44ed663aef Have fun and good luck if you do decide to make either or any air boat

500 lb. koolaid man

Some plans for a new airboat have been brewing in my head lately. Ditching this boat(out for the trash possibly), still gonna be a puller and same motor. Got a question though.

Does 45 degrees sound good for the sides?

Thanks

P.S. I am going to sketch my basic design soon using computer software, I'll post snapshot(s) when done

500 lb. koolaid man

Wow, third post in a row, starting to feel alone hear.[:-]

I was at one of my local hobby shops yesterday and I was asking the owner about building an airboat, then we got onto the subject of using a thin sheet of aluminum on the bottom of the boat. It does make sence though, it's light weight and adds protection to the bottom of the boat on any surface. He said most of the airboats that he knows of locally have aluminum on the bottom, yet I have never seen that even once here at RCU. Anyone done this though, think it's a good idea?

Thanks

crispyspa

LOL...you're not alone, we're still here.

45 Deg is fine for the sides. About the aluminum bottom: Personally I don't think it's a good idea.
If you do water running only, a layer of cloth and epoxy is more than enough protection. IMO

If you want to do dry ground, aluminum (I think) would slow you down because of the weight....even though it would be a thin sheet.
If you want to run on tarmac, aluminum would scratch to easily and create drag when you go back to the grass or water.

Here's how I see it:

Water only. epoxy

grass/water occasional tarmac : epoxy and cloth

water, grass and tarmac. thin sheet of plastic such as coroplast or ABS plastic.

500 lb. koolaid man

LOOKS LIKE SOMEONE DID NOT LIKE MY POLL THAT WAS JUST DELETED[:@]
no freedom of speech here

saleens7

yeah, just noticed that too...

crispyspa

As I gather from reading the posts....there are some copyright issues that need to be dealt with.