1/6 scale Jetsprint boats and 30mm Jet drives

[ManDime]

Hey, so i got a a blue Spartan shell from spartanator and i want to make it into a jet boat. I know someone has done it before with a graupner jet drive but i like supporting small business inventors. So with your jet i would have to cut down the jet drive to make it sit well. Would you suggest i cut the jet drive or should i make a raked cut on the hull similar to your boat designs and fill the gap with balsa with alumium sheet? Also I noticed you ran the leopard 1800kv. I also noticed you said you suggest a top end of 28k rpm's. What did the leopard motor produce? I was thinking of running a turnigy 1500kv outrunner motor with this. Would there be a problem with that? What motor would you suggest beside that? I recently emailed on your site as well. I'll take anyone's opinions on this as well.

[ManDime]

Alright, found the equation. So it's motor kv x Voltage applied = no load rpm. So 1500kv x 14.8v(4s) =22,200 rpm's no load. So with that figured out 2000kv motor is the most efficient at 28,120 rpm's (4s) no load. So heard about how the motor is connected through the email reply. I'll look through the pics again to get a good visual of it all.

[mickieb49]

Paul,
If you wish to put this unit into the Spartan, I would suggest to make a flat section in the last 8" of hull, this does 2 things, creates a ride pad to better the flow of water into the unit, and also helps in mounting the unit.
Please post your results in you thread, I for one will be interested in the results. Just be careful when considering the Kv and max RPM with Jet units, more RPM does not necessarily mean faster, jet unit efficiency drops off at about 20 000rpm.

The Marathon hull plug is nearing completion , I will be posting the results and pictures soon.
Regards Mick

[Mike Caruso]

Hi Mickie,

I finally got my boat in the water using AQ Revolt motor 1800Kv and AQ ESC on 4s it runs right at 30 mph. My Eagle Tree I had setup wrong so no data on speed but motor turned between 18,000-21,000 rpm. Not sure I had 100% throttle as this same style motor turns 24,000 in my Revolt. With that said not bad at all very nice running unit. Very small change in jet nozzle up and down makes BIG difference in boat planning.
I am waiting for video my friend took. Now the problem is with the steering arm being much to thin and small. I broke it off along with the elevator walking through some 7 foot reeds retrieving my boat. Dang! I took it home and fixed it with a small CF knock out from OSE CF battery tray. Anyway my boat is very heavy I will weight it.
Mike

[ManDime]

Almost there with my build!





Just got to do soldering and positioning the motor! Positioning the motor in a boat never meant for this motor mount or drive system isnt easy.....

[Mike Caruso]

Yikes nice boat man, switch to a 4-40 push rod so you can used the 2-56 ball end through bolt. You are going to need an up and down nozzle adjustment to trim the boat out. I only have about 3/4 of an inch of pump shaft inside the boat. I used Octura old style dog and drive pin deal.

[ManDime]

The turnbuckle is adjustable and i have a sleeve in the ball end to make it a snug fit so theres very little slop.

[Mike Caruso]

The turnbuckle is adjustable and i have a sleeve in the ball end to make it a snug fit so theres very little slop.

Oh now I see it sorry my old eyes missed it great Idea mine if I use it too LOL You will be surprised at how sensitive that adjustment is so kool.

[Mike Caruso]

Heavy jet boat 6# 14oz

Heavy boat but you have to reinforce the turning arm. This was a Blemished Mickie Beez Jet Hull that I filled the inside with CF sheets yes sheets LOL. My first CF job it will take 125 mph crash Ha. Then sanded off the four full length bottom strikes. The bottom is just a Vee now. I am still trimming it out to run better. To cold to run today but did add 4-40 push rod for steering. Next is to make one for up and down. You need that adjustment as the slightest down angle and the porpoising is GONE it just stops. Then the boat runs smooth looking like a real Jet Boat. Very cool ran a Grim 4s 5000 through it never even got warm I was surprised.
Mike
P.S. Sorry about pictures.

[mickieb49]

Nice posts guys,
Mike would you like another nozzle?

Point taken with the Steering arm, to change he molds at the moment its going to be a few $$ to modify and beef up the area. So please bare with me , I will get this change done, just may take me a short time to get the funds up to do so. I have not experienced this break yet, but I am only using 2-56 rods and arms, and have double checked the end point adjustment so as there is no excess movement to strain the arm, there is nut much pressure needed to turn the nozzle, certainly not like a normal rudder.
I have just finished building my new workshop, so my first job is to get the Marathon hull up and going, then am going to keep improving the jetsprint hull.
If anyone requires a hull or jet units or parts please PM me , or go thru Steve here at OSE.
Take care guys.
Regards Mick

[Mike Caruso]

Nice posts guys,
Mike would you like another nozzle?

Point taken with the Steering arm, to change he molds at the moment its going to be a few $$ to modify and beef up the area. So please bare with me , I will get this change done, just may take me a short time to get the funds up to do so. I have not experienced this break yet, but I am only using 2-56 rods and arms, and have double checked the end point adjustment so as there is no excess movement to strain the arm, there is nut much pressure needed to turn the nozzle, certainly not like a normal rudder.
I have just finished building my new workshop, so my first job is to get the Marathon hull up and going, then am going to keep improving the jetsprint hull.
If anyone requires a hull or jet units or parts please PM me , or go thru Steve here at OSE.
Take care guys.
Regards Mick

Mickie,
No I don't need another nozzle. But thanks for the offer I made such a easy quick fix adding a doubler as anyone can do I love CA glue on plastics and CF. I would like to have control of the elevator up and down on my 3 channel Futaba 3GR-2.4 stick radio but the 3rd channel is only a switch suppling only full up or full down. I wish I had a thumb wheel like on the radio's before dirt LOL Anyway I have my Daughters camera / video deal with zoom I hope my friend can get us some good shots. Keep up the work on your boats and pump. I should have Eagle Tree results also last time out my speed-o didn't work, but I can get rpm and amps. Maybe back on later tonight?
Mike

[Mike Caruso]

Ok so Garmin said 26.3 mph not trimmed but Eagle Tree said 23 ? And I forgot to plug in rpm sensor to the ET. Dang, AMPS 75-90 while hopping. Gave it a small amount of down nozzle it smoothed right out looked more like 29-30 mph. Everything stone cold but it is 54 degrees outside today. Last run for the year on this one.
All in all good pump great thrust and only running about 19,000 est. rpm. Video to follow.
Great for kids no props to cut little fingers or us big kids too.
Mike

[Mike Caruso]

More on my build Mickiebeez Jet

photo jet drivce octura.jpg
Replaced the soft drive shaft with Harden drill blank. Added BOCA Ceramic bearings and next size brass tubing to space them UNEVENLY. Reducing the chance of any shaft harmonics. Topped off with old school Octura drive shaft couplers which use bushing to reduce size to fit drill blank. Remember to ask Trudy at Octura for reducer bushings when ordering coupler.
I was walking through tall brush and broke the steering arm off at least it was after running the boat. I got home and added Carbon Fiber leftover take your time and fit it up to the nozzle real good then using superglue done deal works great.