dreadrock

G'day Crew,
I haven't been on here for what seems like forever but hey.....
"Similar", i had a quick search for that vid, i know the one your looking for, but too no avail....if memory serves me correct...he made a new model..this site has changed a lot since i was last on here, hence i can't seem to find anything...any rate, i'm pretty shore if you scrolled thru the pix the user made a new deck with a single driver (Wild Willy)..cool as to boot..pretty shore he was running a 28mm drive in there, KMB, Graupner??
Hope this helps some
Cheers Dreadrock

l8rg8r

So I'm starting a new build it's a nqd jet boat with a trx 3.3 nitro Ive modified the pump with a 5 mm stainless shaft and a octura beryllium prop that I filed down to .005 inch clearance I've blended all the rough edges off the housing that's it for now please feel free to comment as always I'm open to new or old ideas

Wheelnut

My Feedback: (81)

Nice job I8rg8r! I would love to see a video of that running.

I have one of these boats with water cooled brushless motor and esc. I think I also have some of the extra props for the jet drive.
Anyone have a good idea of what's a fair price to ask? Everything is still new and not assembled yet. The only thing I've done is cut the hull for access to the electronics. I did a very good job with the cutting.

l8rg8r

Hey wheel nut I would be interested pm me lets talk

mickieb49

Just wondering guys, i am thinking on doing some CNC 3 bladed Alloy impellers for the NQD, what interest is out there? also what sort of $$ would people be prepared to pay?
Regards Mick

sundogz

A three bladed replacement impeller would be great if you could do it with blade overlap like the one in your pump. That might reduce the tendency to aerate (some call it 'cavitation') and easier/quicker to reprime. Also, the three blades would be more in phase with the three bladed stator (flow straightener) than the stock 2 bladed impeller. Don't know how much to charge - but if it's the same quality as the one in your 30mm pump, I would expect to pay at least $25.

similar

Found it
http://www.youtube.com/watch?v=jOdSAX0gH5k

8MILLSNIPER007

I'm not sure this is the best place to ask this but I will give it a go: How well would one of the NQD drives work if one was to put it in a 30 inch ABS deep vee hull and used it as a recovery boat towing a rope with a floating hook on it to retrieve flipped or broken down r/c boats?

MikeHRC

The problem that you might have is that you can only steer under power, when you cut the throttle the boat just drifts (as it is the jet that steers - there is no separate rudder)

8MILLSNIPER007

I know that from riding sea doos, that will be ok. I am more concerned with a jet having enough thrust to tow in a 46 inch boat!

colebz

A good friend and I started a new channel on youtube. Check out the new video of our jet boats and subscribe if you like what you see. Lots of slow motion! http://youtu.be/sJQf2XPtTUE
Thanks for looking!

jandg

Awesome thread!!! But i couldn't find an answer to my issue.

I have water coming in from where my jet unit attaches to the transom. I used Shoe goo to seal it. What would the proper way to fix these issue? Shoe goo has worked for me in the past. I feel that I do not have enough on the transom.

miner mike

I ran it by the guy's at the club and heard up to fifty buck's.

*delete M i k e u p delete*

MM- those cnc props don't live up to the hype as Octura props do. This gentlemen on RC Groups site by the name of Bill from Florida found out that top speed fell by 4 or 5 mph.

miner mike

Hi, Mikeup. I don't think the props mikieb49 was referring to have been made yet. Hoping for something better than we have seen

miner mike

Was doin some work to another NQD jet, made a scoop grate, should have looked it up on the net be fore I made it.

Dongskie

I miss my little jet boat

sundogz

Me too. I should have kept one of them, I had less problems & more fun with this boat than all of the others.

Dongskie

I still have one, but pending BL conversion..

But here was my first one

sundogz

Good looking boat, Edgardo! These are fun to convert.

Haje74

Hi guys,

Im a modelbuilding nut with a soft spot for jet-drives like most here, and I have been working on a file for making simple calculations on RC jetdrives in order to determine the power one needs to achieve a certain rpm and therefor jetspeed. With this file you can get an insight in what kind of setup (batteries/e-motor) is most likely to give the result you want from your model jet-drive.
It is easy to use; just fill in the required numbers, and it will show the required power to reach a certain RPM.

I have posted this very same text in the "all things jetdrive thread", but wanted to make sure you guys wouldn't be left out.

Remember this file is a first setup; there are numerous more variables to consider, but it is a handy tool that will give a good estimate as to which setup is most likely to work, and which wont.

You can download the file here:

http://www.powerboat-friends-freisin...English%29.xls


Try it and see what you think; any comments on improvements are welcome.

Have fun with it!

Cheers,

HJ

sundogz

Haje, I saw this on the other forum and you might want to let others know how to use a spreadsheet so they can try it out for themselves. Can you tell me where you got the figures to work with? - what personal experience you have with jet drives, etc. This is a good idea & concept - worth pursuing to be sure. Sdg

Haje74

Hi Sundogz,

You're right; I should introduce myself. I'm a composites engineer from Holland. I've been working in composites for about 20 years, and I do some modelbuilding at home for a hobby. My family has been sailing the Dutch coastal waters for as long as I can remember.

Like the English we too have a Royal Lifesaving Institute, called KNRM . They run a state of the art fleet of several types of jet-propelled vessels that will do up to 45 knots depending the type. These boats have had my interest since I was a kid; aluminium built, modern SAR equipment, twin diesel engines, with selfrightening capabilities. One particular succesfull design is the Valentijn-class; a 10 ton, 10.5 m rhib built in aluminium with twin 430 HP diesels driving twin Hamilton jets, capable of doing 36 knots.

I am in the (lengthy) process of building a 1:7 scale (60 inch) model of this particular type, and am currently working on my own design for a couple of dual stage water jet units to go with it. I have built a 1:10 scale model of another rhib using twin graupner 28 mm jet drives in the past, and have a couple of graupner minis and KMB-units laying about still waiting to be used in a model.

In my search for information on jetdrives I came across the website snikwah jets, and learned about how people there used Bernoulli's law to calculate jetflow efficiencies in designing their own jetdrives. I just put the basics in this spreadsheet. What it does is tell you what kind of power is needed to reach a certain rpm and theoretical jet-velocity @100 % efficiency. So if jet-velocity is lower than the outcome in the spreadsheet, you can determine the actual efficiency of your particular jet unit.

See for yourself: Its a handy tool that will help you estimate the efficiency of your unit, or help you choose the right engine for the optimal performance of the driveline in your model.
It is fun to play with and people are already giving interesting feedback about its accuracy.

Below a picture of the Valentijn Type Lifeboat, and my model in the making.

Cheers,

HJ

Haje74

Hi Mick,

I would have interest in a couple of four-bladed impellors with overlap for the Graupner mini.
four bladed because imho I wouldn't combine a 3 bladed impellor with a 3 bladed stator for cavitation reasons and unwanted pressure peaks on the miniscule stator. 2 bladed impellor with some overlap is also an option imho for the small Graupner mini. Can you let me know if you would be willing to help me out, and at what costs?

Cheers,

HJ

bqspeed1

Hi Folks,
I'm totally new to jet drives for boats. Was looking at getting the standard NQD 757-6024 drive with 390 motor from ebay. Anyone know how much thrust this provides?
From what I've seen so far, replacing the stock 390 motor with a brushless motor greatly improves performance, is this true?
One last question - if I briefly connect a 2200 mAh lipo battery to this setup (no speed controller, just for a quick test), would it burn out the motor by overheating, or would it be ok to run 10-20 seconds?
Thanks!