Jet Drives

[inventing_man]

I'm looking at mini jet pumps. Can Anyone out there share the pros and cons.Jet drives (http://www.hobby-lobby.com/jetdrives.htm)

[john mc lucas]

There's a few links and talk about mini jets, over in Racing Boats Electric
Thead- Water Jet Powered Boats By JoeR1 maybe helpfull
Cheers, John.

[quicksilver]

well, I'll bite.

pro's,
ability to run shallow water, were talking less than a 1/2".
maneuverability
fun factor (kind of the biggest pro)
you can make them fast, how fast I dont know, never gps'd mine.
drives are cheap considering you dont need any other hardware.

cons
cant legally race them
speed is ultimately limited by the design, but again it depends on what speed you're looking for.
parts are almost impossible to get, so if something breaks, you'll most likely have to buy a new drive for parts
vulnerability to pebbles, which can break the impeller or stator, but I believ the mini-jet comes with a grate which helps.

that's about it.

can check my videos out here, to give you an idea
http://www.youtube.com/profile?user=quicksiler

[inventing_man]

Thanks for the info . The application for this drive is not for top speed . Actually just the oppisite. I'm looking for slow speed grunt. Are these drives good with low speed pulling , or how could they be modified to do so ?

[patmat2350]

Thrust is thrust.
If a boat is light/slick etc., a given amount of thrust will make it zip across the water.
If a hull is deep/heavy/draggy, the same thrust will move it and its tow slowly.

While we had some pix here of a large 1:1 scale littoral patrol craft with jets, I've never seen them applied to a 1:1 tug... maybe that says something?

PM

[Kmot]

Here's a 78000 pound brick, using jet drives:

http://www.efv.usmc.mil/images/moveland-1-lg.jpg

http://www.efv.usmc.mil/videos/move-water.wmv

Pretty darned impressive!

[Tugboat Andy]

Here's a 78000 pound brick, using jet drives:

http://www.efv.usmc.mil/images/moveland-1-lg.jpg

http://www.efv.usmc.mil/videos/move-water.wmv

Pretty darned impressive!

If I hadn't seen the movie....I wouldn't have believed it.

[MILLERTIME]

I want one, do they come in Blue?

[arrow5]

Wow ! so lightweight and slippery...like a Springer ? Toes;your next project !!!!!! I shudder to think what the fuel consumption is. Great movie but I`d like to have seen it exit the water.

[Shaun Hendricks]

Thrust is thrust but the difference in props and jets is efficiency of thrust from same power plant. Jet's lose about 15% efficiency over the same power plant using a propeller. Inboard/Outboard drives lose efficiency over direct drive (ski boat) style systems.

Each drive system has pros & cons and marine designers are well aware of them. You put the drive on the vehicle for the purpose the vehicle is designed for.

I'd never use an exposed prop boat in a shallow river, just like you'll never find jet drives on offshore racers. Racing boats can't afford to lose 15% efficiency.

(The 15% number is just a ballpark average, actual numbers vary with the jet drive type)

[785boats]

If you can find some plans I'll build one.(after the stingray)
Paul.

[Kmot]

More info:

http://www.efv.usmc.mil/

[bigford]

leave it to the marines :eek:

[nick_75au]

Is it possible that the site may be blocked from non us ip addresses?
I'm in Australia.
Regards
Nick

[craig_c]

Ahhh.. ingenuity!!!!

With the F-4 Phantom we proved we could teach a brick to fly, now we've taught one to swim as well!! Let's hope EFV serves as well as the F-4.

So . . .

Who's gonna build one?? :D

[arrow5]

I reckon Nick75 will, as soon as he gets the pics., he has already done an Oz military Springer. Some similarities. Swimming brick , he he good one Craig.

[Kmot]

Is it possible that the site may be blocked from non us ip addresses?
I'm in Australia.
Regards
Nick
I doubt that very much Nick. If it were a security thing, it certainly would not be very secure because any friggin' terrorist who wanted to could get their buddies in their sleeper cells here in the USA to download and then send them via e-mail. Or simply post them in a thread like this. :p

[john mc lucas]

I havent had any problems with acess to that site and i am from down under,must be some other cause.

Cheers,
John.

[meechingman]

Jeez, that's almost unbelievable. Even Thunderbirds had nothing on that!
Andy

[quicksilver]

I watched a show on that thing recently,unbelievable. Theres even little doors that close off the jet drives when on land. I think they had failed to mention fuel consumption which must be insane.

[Kmot]

More video if anyone is interested:

http://www.youtube.com/watch?v=30XX4QcWkTU

http://www.youtube.com/watch?v=abWIjfFa26s

[785boats]

Kmot.
Any ideas on how to get some drawings &/or dimensions ?
Best regards,
Paul.

[Kmot]

Kmot.
Any ideas on how to get some drawings &/or dimensions ?
Best regards,
Paul.
http://www.gdls.com/pdf/EFV.pdf :D

[Kmot]

Another cool video I found:

http://www.gdls.com/images/EFV%2007.wmv

[785boats]

Kmot.
I'm afraid it just comes up as Error FW-1 at Fwlss09h: "access denied" :( Thanks for trying.
Damn.
Paul

[arrow5]

Worked OK for me. Impressive. Try General Dynamics on Google it is a company promo film. Got the answer for Springer diving, a big ramp at the front !

[quicksilver]

I know you guys are into details but couldnt one make a wooden APC and incorporate jet units into the design. then somehow get the needed tank parts. Would be a very cool model. It would have to be almost 2ft long to use graupner mini jets. Unless you're real handy and can use one jet unit, have it inside the APC and have the nozzle split into two nozzles. Doing it that way, you might be able to get it down to a foot long.