mjderstine

ok guys, check it out.

and give your opinions too. this is a design is just drew up to show a basic idea of a highspeed tunnel hull style airboat. i used google 3d sketch. awesome sketching program btw.

it measures 40" by 20" and that prop designates a 14" prop. the motor is elec as you may have guessed. the motor mount was drawn before i did some modifications to the overall hull this is why its separated from the hull.
the curves were the most pain to draw and dont line up properly, but it gives a good idea.

and of course for high speed control there is a water rudder design incorporated.

the inner hull will most likely be more rounded when completed, not a sharp angle.

SFGuy

Looks good. Looks like something I would like to build but scaled down a bit because for an electric airboat of that size thats alot of $$$.

mjderstine

ive got the motor and esc for it already. all i need to invest in is some 10cell Lipo packs...

mr. ilikehelp

i agree scale down.

what size moter

mjderstine

here are some updated drawings of the boat. i have to draw a 3 view of this thing now so i can start printing some templates.

mjderstine

here are some of the updated pics of the construction. these are the main bulkheads that will make up the rear 24" of the hull. there will be 12" between each bulkhead. i am also going to put 1/4" stringers on the inner corners of each bulkhead.

the large pice represents the bottom of the tunnel section. the piece in the pic is the same material i cut the bulkheads from. 1/8 birch ply.
more pics coming in the next few days.
couple more pic of the progress. it has glue on it now.

should be framed up at the end of the weekend.




and its gluing.

the 1/4 inch stringers

the stringers were epoxied in place while the bottom sheeting was put on with titebond 3 and lots of weight and clamps.

the stringers on this are not cut to length yet, however the boat will actually be 4 inches longer than the pictured 36" length of the stringers.

i took some pics next to my BSB just for some comparison of size pics. with a 1.08 (bored out .90) it should have plenty of speed!!!







wouldnt be a build thread without lots of pics. here are some more.
its BIG. inner hull wall is 1/8 ply. top of sponson is 1/16th.

i plan to start the front of the inner hull tomorrow night.








maybe i'll get some feedback now since its a realy boat and not just a drawing. [>:]

Selph-Inflicted

Nice work!!

I really like your use of the kitchen table, or should I say kitchen work bench!

Can't wait to see this creation run in person!

mjderstine

you will probably be one of the first to see it go full throttle!

i live in an apartment, so everything is a workbench in my place. really makes things easy, but can make things messy at the same time. i put MDF board over all the countertops so i dont damage anything.

SFGuy

looks good. im keeping an eye on this build. as soon as im done building my "miss take" i might start on something like this. with electric of course. why did you change it to nitro?

mjderstine

well electric for me right now is a little pricey. the batteries alone to get me going would at least $400 smack-s-roos. it was just easier to start with nitro. i am going to design a removable motor mount so that down the road i can get a elec motor on there. i still have them! just on the back burner

Mr Cajun Gator

Nice build post you have under way. Very nice workmanship. The sides have me a little concerned, that they will grip hard in the turns.

mjderstine

you mean the outer side of the hull will grip hard on turns correct?

Mr Cajun Gator

yes where the side meets the bottom

mjderstine

i have thought of that as well. since this is the prototype i am planning on this setup for now. i already brainstormed some alternatives to a scenario such as gripping to hard, or even inherent flip overs due to the outer hull digging in the corners.

one possible solution would be to invert the angle i have on the hull so it is angled up instead of down, and then widen the inner hull for a wider stance all together. it may just be a second design once this one is done, and the testing is over.

my reasoning to the downward angle as opposed to upward angle is to help prevent blow overs once the boat is on plane. (which i hope will be most of the time) there will be so much air flowing below the boat from the tunnel design that i wanted to try an help blow overs as much as possible wit the downward sloped sides

another goal of this boat is pure speed, but in a different design than the 3 pointers most guys use. 3 points are very stable at speed, and i just wanted to see if i could make a tunnel hull about as stable and get close to the same 40-50mph the guys with 3 pointers are hitting. if i can, then maybe it will start a new high speed class of rc airboats with tunnel hulls and 3 pointers competing for out right speed honors.

thanks for the advice and support guys, keep it coming.

savageguy25

hey man nice boat not tryin to steal ur thread but heres my tunnel i started buildn and havnt had time to finish all i have to do is glass it


http://s126.photobucket.com/albums/p104/mikehowse/ let me know what u think thaught it might spark a few ideas

mjderstine

hey man, its not letting view that stuff. dont worry about stealing my thread. i like the input. but i still cant see the pics. it is making me log in to your account.

any way...

here are the updated pics.
the front of the inner hull is going on,

here are the pics of the glue drying. there is a 1/4 x 1/8 stringer on the front to make sure it stays sealed.

savageguy25

ok maybe this will work theres a buncha pitcures of boats ive drawn on there too but the bottom pictures ore of 1 or my airboats it has a os 40 4stroke http://s126.photobucket.com/albums/p104/mikehowse/

muti369

you can download swap buggy bits and pecies on google sketch up in the get models section or get whole air boats

mjderstine

thanks man, i'll lok on that google sketch up thing for some ideas. this is just a prototype. i have a feeling once this gets in the water i may make lots of changes on the next one.

muti369

that is what im using to design my first air boat im bulding it out of carbon fiber its 21 inches long with a 165 mm ducted fan

muti369

if you put a flat board in the tunnel \ kinda like that at the back of the tunnel it will make it lighter on its toes it will turn faster and go faster because of the air pocket under it holding it up

mjderstine

i have angled the entire iner hull area up a little so that at speed tha angle of attack will make the boat want to rise of the water. if i need to i can build an adjustable wing on the front of the sponsons

mjderstine

here are the actual motor mount stringers. they are 3/4" pine that is glued to 1/4" hobby ply for some added strength. right now that is almost no flex anywhere on the boat.
you can see how they are flush with both attaching bulkheads
everything was glued with titebond3. awesome stuff

added a 4th front bulkhead for the sponsons. this will really help the construction of the sponsons

i got the small front compartment edged with stringers for a hatch, this will be where the GPS can go.

the mount sides just sitting on the stringers for a visual of the setup.
they will be 4 different mounting positions for different types of handling

got the bottom stringers beveled and glued, i will also put bolts through this part for added strength.

mjderstine

its a boat now! kinda