I went with a 24* vee. Flattened out 1-1/4" on the bottom. Its all meant for a graupner mini jet/brushless outrunner. Here's what I have so far just waiting on parts now. Its going to be a tight squeeze. I might have to make the hatch bigger to get the battery in/out.
Hull demensions are 15.5" long 6" wide.

In the pictures the top is just taped to get an idea of how things will be. Still work to do on the hull obviously.









more to come...

Really nice hull from scratch, i like the thransom good idea for it!!! it would be really cool if you made a cowl for it, you may even be able to sell the plans for one Really nice work.
Dan

Nope can't do that. Atleast not without feeling alot of guilt. I got the plans off the net, I forget where. The plans were for a hull 48.6 x 15. I shrunk the plans to 40% of the original size. Then I chopped 4.5" off the back of the boat length. Made corrections for the material sizes I would be using. After printing and asemblying a hard paper version I found a few things wrong with the plans. Might have been my fault though. I corrected my version and made it out of wood. Ofcourse there are some differences. Like I mentioned its not only shrunk its also chopped to a shorter length. I'm hoping this will give me a sharper turning boat. I'm not looking for high speed but more manuverability and spins. I then chopped some off the bottom to create a 1-1/4" flat spot for the mini-jet. From what I'm told the mini jet is about 1" wide so I should have plenty room (Fingers Crossed). I wont seal the hull nor glass untill the jet gets here.

Oh and I will be making a cowl soon

If anybody wants a copy of my version of the plans just email me. [email protected] Please note weather you want the plans as Corel Draw or exported to JPEG

hey, nice hull . I like how you shortened the hull, a bit more beam to length ratio is a good idea. I also notice you said you might go brushless, I saw the mini jet is supposed to use a 500 race motor, which is supposed to put out 17,000 rpm at 8.4v. Since graupner does not give its jet drive specs, I'd assume you dont want a motor thats going to turn any faster than say 18,000, anymore would probably be a waste. This is a good thing though, since if you go brushless you can save some weight do to decrease in cells. Try to keep the cg pretty far aft. Cant wait to see the progress, I'm still waiting for my tax return so I can get my motor..... [:@]

Food for thought,
I've got a Eflite park 480 brushless. And a 3 cell lipo. The park 480 is rated at 910 rpm per volt. Being a 3 cell thats 12 x 910 = 10'920

So we shall see if its enough.

If that's right, get a 600. 10,900 isnt going to do it, is that free spinning or under load. If its free spinning forget it.

The jet is made for a certain range rpm and will run efficiently unless you have that rpm. With a hull like that, you better have some power....

I built a cheap 20" ABS mono with one of these jets and at 17 turn (I think) car motor, 6 cells and was incredibly slow, like walking pace, and that motor would have higher revs than a 600. It was probably mainly because of the hull size, but I think the jet was also fairly inefficient, as there was alot of friction in the driveshaft, and the impeller wasn't vey well designed.

I've never seen the mini-jet, nor its bits, but the 29mm was fairly quick. I had a 15" semi displacement hull with a 29mm in it, running 7 cells, did about 10mph and had ridiculous power, but the hull was horrible (nikko).

nice boat..so this is the project you were talking about huh. cool!

about the motor. since the hull is a bit smaller than mine. why not look for a similar motor?
I have a feigao 380 9s. around 4400kv and on 6 cells. I think the speed is okay. would be nice to have a bit higher topspeed but it runs good. I've tried it on 8 cells to but the motor, esc and battery got warm and the speed didnt increas that much.

I think you should aim for a motor and cell setup that will give around 25000rpms while its not under load.
might be wrong on that, just talking from my own experience with the minijet.



Jocke

I wish Graupner actually knew the max. efficiency of their jets, it's ridiculous. That does sound like a good setup joccee, if the motor turns too fast you can just decrease the cell count further, though with a kv of 4400, decreasing below 6c, will well drop the rpm's a lot. So yeah that exact setup sounds good.

BTW, I worked on my variable nozzle today, I've got to go to work, but it's all mocked up and ready to solder..

Well looks like I'll be hitting up ebay tonight. Need a lipo balancer too

Don't forget to post pictures


Specs:

Quote:

Requires:

20A to 35A Brushless ESC
10x6 to 12x6 Prop
7.4V or 11.1V Li-Po or 6-10 cell Ni-Mh/Ni-CD
Features:

High Torque, direct drive alternative to inrunner brushless motors
Includes mount, prop adapter, and mounting hardware
4mm shaft can easily be reversed for alternative motor installation
High quality construction with ball bearings and hardened steel shaft
Slotted 12-pole outrunner design
Specifications:

Type: brushless
Size: Park Flyer
Bearings or Bushings: Bearings
Wire Gauge: 16
Recommended Prop Range: 10x7 to 12x6
RPM/Volt (Kv): 910 (RPM per volt)
Resistance (Ri): 0.08 Ohms
Idle Current (Io): 0.85 @ 8V
Shaft Diameter: 4mm (0.16 in)
Weight: 3.1 oz (87g)
Diameter: 1.4 in (35mm)
Lenght: 1.3 in (33mm)
Continuous Current: 20A
Maximum Burst Current: 25A for 15 seconds
Cells: 6-10 NiCd/NiMh or 2- to 3-cell LiPo
Speed Control: 20A to 35A Brushless

One more time,: 910 rmp-per-volt x 11.1v's which is my 3 cell lipo pack = 10'101rpm
Seeing how I want optimum rpm (18'000 ish) Lets go, 18'000rpm / 11.1volts = 1621 kv


So I need something around 1600kv Any suggestions for what motor to get? I should add I have a Eflite 40 amp ESC
Does that sound right to you guys?

Heres what I found so far,
AXI MODEL MOTORS
AXI 2814/12 GOLD LINE 1390 RMP/V MAX 35 A/60 s

AXI 2808/20 GOLD LINE 1490 RMP/V MAX22 A/60 s

Comparable to

Eflite park 480-910 910 RPM/V MAX 25A for 15 seconds

So it seems a better rpm with a longer full throttle hold. What do you guys think?

bah, I dont know, I dont even own a brushless motor yet. where's taylor?

i think the brushless out of a sv27 is 1600kv. maybe keep your eye out for something like that.

Lol i know hes playing with his new ping pong table!!
Dan

Progress, Some glass / epoxy for strength.

unitedhobbies.com has cheap fiegao's, 540s, 540l, 540xl, they also have 120a and 80a esc's

already got a brushless setup... Tell you about it later on when it gets to that point in my post.






Next up.
-Sanding
-Reinforcement ribs for side decks
- build hatch
- fiberglass
...etc

very nice

Next up. Spacer + new universal joint. The original just wouldn't cut it. It was a 2mm to 2 mm u-j. Needed a 3mm to 2mm. Picked that up at the local hobby shop. By the way I made my spacer out of hard green nylon.

Here's plans incase anybody else needs them,

Here's how it looks on the boat,


Likely I'm going to have to trim 1/8th off the bottom of the spacer for clearance.

very nice. the out runner will have a boat load of power for that !

I think I'm going to need a a new mounting plate as well, glad it wasnt too hard. I was going to use aluminum,, but I guess only time will tell. Looks good.

http://www.trademe.co.nz/Toys-models...p-36359373.htm

check out this jetboat

Thats really cool,i wonder if my 45" hull will take 2 jet drives...

Take a picture like this of each of your mounting surfaces, ( Make sure you picture is clear like this one. And high resolution!)

Then measure this dimension out. <--- Keeping in mind the location of the universal joint to the shafts.



I'll draw you up something and you can make it out of a hardwood, have a machinst do it, or I'll do it for a price based on time to make it + material.

[email protected]