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You are right about the graupner drives, didn't realize they went under. I know a guy that makes replacement parts, or at least he has made a part for me when I still had my 29 mm drive. Are you accepting pre orders? I'll buy one of your drives and do my own R & D on motors if you get one put together. Maybe you could cut me a lil break on your prototype and ill be sure to give you feed back.
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Hi, Thanks for the offer, and may take you up on that, as long as you will put your honest findings on the pump here for everyone to read.
I am still waiting for the impellers to be finished, plus the finalisation of the injection molds will hopefully be done very soon.
Will keep everyone updated as the progress continues.
Regards MickComment
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Iv'e been looking for a pump also , looks GREAT . MikeComment
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Darin we should make a NAMBA class and course for jet sprint. It's been a dream of mine for years. Now if we could get a quality pump at a decent price.... Money is burning for a jet pump . Have a cheap hull with a shallow vee waiting to experiment with.Comment
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Thanks for the keen words guy's,
I have to wait for china to get back from a puplic holiday before i can get some progress updates from the manufacture of the pumps, also get a transformer for my vacuum former.
Plans for the jetsprint hull and the Marathon river race jet boats are getting closer too, hopefully i will be able to cnc the plugs out in the comming weeks.
I have also got hold of a supplier that i am a wholesaler for now for the ESC and motors, Just wondering if it is actually worth putting this option out there for everyone? Also thinking on more like the $120USD each for the pump , and around the $130USD for the hulls, kit for $299 ( this will include the Pump, Hull, Rollcage ( CNC fittings) , Dummy drivers, stainless pump cover, Uni joint for the drive shaft.
I do really appreciate everyone's patience, this has been a long winded wait, hopefully it is worth it.
Warm regards MickComment
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This all sounds great Mick. Look forward to it coming together.Comment
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Got 120 ready to go for the first oneComment
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Any updates?Comment
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Hi, no sorry nothing yet, still waiting for the impellers to be finished, also waiting for the final changes I had to make with the injection molded parts.
I am so sorry for the long wait, unfortunately china had a public holiday for that past week and that really buggered me up.
Again I am sorry for the wait, I will do my best to make it up .
Regards mickComment
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Don't stress it. I will patiently wait.Comment
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Hi Mick,
I see it is coming along very nicely. I have a question I know you have been testing for ten years off and on. I wonder what size motors and cells you have used? Juts tring to get an Idea of power required to turn that impeller?
Best,
Mike
P.S. Like TheShaughnessy says 'Don't stress it. I will patiently wait.'Do It Like You Mean It .....or Don't BotherComment
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Hey mike, mic probably has a better answer but if I can get my hands on one im going to power it with a 1800 kv proboat, I'd prefer to use a 1500 kv but the wires on the one I have are kinda sketchy, got it pretty hot a few times.
No idea on how this one will perform, and I feel bad even comparing it to a graupner drive ( because it seems to be a much better design. ) but that's all I have to go off. My personal experience/ observation with the 29mm graupner drive was that one you got to a certain rpm it was maxed out. Once I hit 3/4 throttle I was pretty much at max speed. I could squeeze the trigger more and would hear more rpm but not see any increase in speed. A few of us on RCU agreed the max effeceincy RPM was right around 21,000. I don't think we were using stock drive lines though. I know I changed the stock tubing for one that fit a .150 flex with a 3/16 stub. I didn't use a Teflon liner, but if I were to do it again I definitely would because I never could keep the water out and I'm fairly certain it was getting force up through the drive line. My original intent with that was to be able to use a drive dog and be able to use a Cu prop but wasn't able to because I couldn't fit the drive dog, prop and a nut between the guide vanes and the new tubing so I ended up taking the threaded insert piece from a stock prop that got chewed up and force fitted it into a 3/16 bore Cu prop. That ended up working pretty good with a s220 I had. it was a lil banged up so I figured it wasn't much of a loss if it didn't work out. I put it on a flex ran it through some brass tubing with some grease then clamped that down with my rotary tool hooked up to the flex. Spun it up and ground it down until it fit.
The two pumps use a completely different impeller design. The graupner impeller is just a 2 eared surface piercing prop design it isn't really an impeller at all, more a prop in a jet pump, mics design mimics a true impeller design found in full size jet pumps so his may not max out like the graupner.
Here is a pretty bad still camera vid of a set up I used to have.http://m.youtube.com/watch?v=2Ci9MCl...ture=c4-feed-u Pretty sure it was the stock plastic prop here. Not a good hull and pump match (didnt know any better at the time, but it was entertaining. Using a blue can aquacraft 3656 and 45 amp esc from a super vee on 4s lipo ( might be 12 or 14 cell nimh in the video. It was a while ago). Started out with a graupner speed 600 ( I think) and 7.2 v nicad stick packs it was pretty slow. Added a couple cells and it was better but run time was horrible. Sat on a shelf for years before I got a hold of it and revived it with a new power system. http://m.youtube.com/watch?v=2Ci9MCl...ture=c4-feed-u
That turned into a tangent. Doesn't even really answer the question. I will ( assuming I get one) run eagle tree on the 1800 kv set up I plan to try with it and post the graphs. Should give a pretty good idea own how much power is needed. I never had any heat issues with my previous set up running 10+ min at a time but I was usually messing around in moving water and rarely running WOT.Comment
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Hi Guy's,
Like what was previously mentioned, i will be using a 1800kv 4072 leopard motor with a 120 amp swordfish esc on 4s 5000Mah 40c battery, this setup has been good to me with no overheating or problems. That was with the Graupner units and Kehrer ( highly modified, see also my youtube vids)
This unit like the tru Hamilton and Scott jets is not intended on trying to spin it over about the 25k mark, if you try to do that you will start getting a hydraulic locking effect and basically the effeciency will drop off. All too often i see people putting 4000kv motors into those NQD jet boats and running them on 3s and even 4s, then wonder why theu have problems?????
This is a mixed flow pump and like Shaughnessy has said is a very different type of pump as compared to what is basically a propeller wrapped up in a inlet ( graupner and Kehrer)
I will be trying lower kv motors but i believe the 1800kv to be the best.
I am hoping to be able to share some more pictures of the new hulls very soon too.
Here is my youtube link:
Regards MickComment
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Greeting lads,
Just a little update, i have had some not so good news, the manufacturer who was doing the impellers has informed me that he may not be able to do them for me as the CNC mill he has is out of action, aparently they have been waiting for a part to get there from the US for over a month so far, i am hoping to hear back from him today or tomorrow, if he cant i do have another manufacturer who can get them done , just a little dearer ....
I should also be getting the first of the redesigned injection molded bits at around the 25th of this month, then if all is well then we should have the injection molded parts within a week following,
Still also waiting to get another Router bit to finish off the plugs for the hulls.
Thankyou everyone for their patience, i think everyone can appreciate the time and effort ( and off course $$$) that goes into manufacturing these in a large scale.
Regards MickComment
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