ISIRC10

Well, its time to start another project, as finals are coming up and the best way to get rid of stress is to build stuff!
I am thinking of making this a relatively "normal" boat, using modified plans found at the MABA site. I am going to use an experimental jet drive to propel the boat (If it moves then it is successful) made out of a bilge pump from a full size boat. IF that doesn't work, I will probably make it a surface piercing prop, but since the hull is a typical airboat one, I figured that I might as well post it here. I am not quite sure how I will position a rudder as the stream is pretty strong...

anything that you guys spot that could be a potential problem? what should I change right away?
any advice will be taken into consideration, as my previous boating project turned into a failboat... but I learned!

Dimensions:
24" long
12" at widest point
rake starts at 12" from back
6" at narrowest point

toesupwa

You will probably find a 'bilge pump' wont have enough force to move you boat very fast.

ISIRC10

I put a different motor into it and made the nozzle so it would compress the stream a bit more. I will post a video later today showing it at max thrust so you can see and tell me your opinion... the boat's target weight is three-four pounds, electronics are 2 pounds. the hull will be made from balsa and sheeted with thin plywood. Then I plan to coat it with polyurethane or epoxy.

ISIRC10

hmm... seems that you are right.
although they are good at moving large quantities of water, they aren't very good at moving it quickly, nor are they good at holding the backpressure generated by a smaller nozzle...
I may try to build a jet pump from scratch, resembling the Graupner, but chances are that it will probably be even less powerful...
That leaves me with two choices, prop driven in air or water, and I will try both (water first because that would be kinda unusual[8D])

Its a bit sad that this project is being derailed ALREADY, but hey, I guess that it's better to have that happen now then when I am nearing completion.
Thank you for the doubt expressed, as it helped me realize I need to think this over... now to plan B

mr. ilikehelp

want unusal buy a small jet engine and put that on ur hull

ISIRC10

LOL!

[X(]

one problem... the "buy" part of that would not really work out as I am making do with the little stuff that I allready have, a jet engine, Bl motor, or nitro, not being one of them...

but I do have a few spare rocket motors lying around, although retreiving the boat would be kind of hard (unless it blows itself to bits, then you just pack up and leave)

right now, I am just making the hull, then I will try to do airboat thing, and if I don't have enough power, I could beg for a bl motor and a lipo, while having it running with a normal prop (in the water)

will post pictures of progress soon

crispyspa

I found this:
http://www.hobby-lobby.com/jetdrives.htm

not bad for on price either.

ISIRC10

HMM... seems to be a viable option.
and what a coincidence, just this morning I changed the length of the boat to 24"

I wonder if it comes with the motor and if it is strong enough to get a three pound boat on plane?
has anyone had any experience with these?

and another question: how bad do these flat bottom boats skid when they are in a turn? cause without a rudder and only the jet drive, I am worried that it will be uncontrollable.

any help is appreceated (I spelled that wrong, didn't I?)

ISIRC10

I finished the framework for the hull, and it weighs in at 7oz. this low weight helps my reasoning as the previous boat, one side of the hull weighed the same, and the motor moved it, although not to plane. Using this logic, I guess that I can try to make this an EP airboat, then try for a jet drive (I am starting work on the 23, minimum wage, 6 hours a day at this guys garage, fixing real size boats)
Yes, I remember that I promised pictures, but can't find camera, yeah lame excuse, I know.
compared to my previous boat, this should be a featherlight, even though it is wider and longer.

ISIRC10

good news and bad news...
the bad news is that we had a substitute in Math class today and she tore up my design for the motor mount. I realy can't understand people like that. My normal math teacher lets me draw after I finish the final review packet, because he is just cool, s I just took oout my graph paper and started planning, when she comes over (imagine a short lady sulking) and takes my drawing, tearing it up in front of my face and letting the entire class know that we should be READING, not DOODLING!!!!![:@][>:][&o]

...afterall, I had finished all of the work in that class, just need to take the final on Friday and I am done for the year. and really, how could reading a silly little book help me in life, I mean seriously, she must have been some english teacher or something. The thing that bugs me most is that the person next to me was texting his friends the entire period... and she called my plans doodles... tell me, do these look like doodles to you or am I just going crazy???

Rant over:
now for some pictures

dadkins

Skin that bad boy and put a motor on it !

alloutcustom

I think theyre interesting doodles, if you run a surface drive its just gonna spin out, i would recomend a drive like the crackerboxes have. parallel to the bottom fo the boat but the prop if submerged. Or if you use a straight shaft, stick it out the bottom but have it stop after the transom but have maybe a cm of water between the top of the water and the boat and the prop if you understand what im saying.

mjderstine

that looks very cool. i drew my idea on good sketch as well. it really helps in the design phase. i cant wait to see what this does once it on the water.

ISIRC10

here is how far I am with skinning the frame...
should be finished (hopefully) by friday
using polyurethane glue to bond (gorilla glue but made by elmers)

mr. ilikehelp

depending upon if your jet boat works instead of a jet engine go with like a turbine or somthing or go water and air prop driven frome the same moter and have a 3 rd channle to raise and lower the water prop so you can run the boat on snow. know for you r bildge pump if you got another ona nad had them pump water into a chamber where preasure could build you could have it come out a small nozzle

dadkins

Being your on a budget - how about mounting like 5-6 bottle rockets to the back with a metal mount/blast shiled.
I have about 500 bottle rockets that I hate to use on the 4th - (leave sticks everywhere)
Eeeehhhh.....Eeeeeehh...

Now picture 5 one foot flames coming out behind ! Thats what I'm talkin bout !

mr. ilikehelp

go by pvc and make sugar rocket engines just look it up on you tube and but like 3 2in. by 8in. of those and it will fly

ISIRC10

propulsion systems set aside, here is the hull, bottom skinned, need to polyurethane the insides and then put on the top.

ISIRC10

going to go pretty standard for my first try, airboat it is.
second, it'l be a water prop, and third, a jet drive.

going standard cause I think I need something working and recognisable to demo for people, and cause my other project was pretty weird...
here is a vid if you want of my previous one (not the airboat, but in between it and this one)
[link=http://s215.photobucket.com/albums/cc21/ISIRC10/?action=view&current=00001.flv]http://s215.photobucket.com/albums/cc21/ISIRC10/?action=view&current=00001.flv[/link]
here are some updated pics, I will be going away to the susquehana river (north branch) to go camping, should see a lot of airboats there!

crispyspa

O.K....I give.....what is that rc car shooting? Pretty cool though.

ISIRC10

6mm BBs, very effective against poeple who annoy you
...also very effective at getting you in trouble for nothing...

ISIRC10

well, I got back from vacation, it was very relaxing. saw some airboats (man those things are noisy![sm=what_smile.gif])
saw some lawnmower and atv drag races also, they were cool.

back to the boat...
I have it mostly skinned, just need to glue on the pannels in the front. The first picture shows my ballance point, hope that I got it right this time. then I have my waterproof compartment, checked it for leaks today and found none. now I just need to glue on those pannels, sand, place the electronics and cover with polyurethane. then we have float tests and sea trials!

more updates coming up soon.

bigtreds

looking good.

ISIRC10

oh... another question...

where do you guys put the antenna?

do you put it inside the boat or along its top deck, or do you put it in a tube like car guys do? if so, where, right above the reciever?

500 lb. koolaid man

In a tube above the receiver gives the best range, that's how most RC airboats have it.