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The Unofficial all things Jet drive thread

Old 04-28-2013, 11:51 PM
  #4826  
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Default RE: The Unofficial all things Jet drive thread


ORIGINAL: SicRC

I'm hearin' ya brother... she who controls the purse string is the bane of the hard core hobbyist Dunno if you've got a KMB 28mm jet unit in that collection of yours but I've just made a hull that it'll drop straight into, I'll be testing it tomorrow so I'll put up a youtube vid and post a link here. I'm a couple of weeks off having a 540mm version of the Jet Sprint hull kit available that also takes the KMB 28, it's modelled after KMB's 'Splash' hull which is an awesome design... just no good in rocky rapids being made of fibreglass... mine will be 2mm ABS so it'll be tough as nails, also gonna make it available in 2mm polycarbonate for those that want to paint 'em up.

HI
I do have a KMB 28mm but its in the Jetski top of wall so not free. I think KMB have just had new stock of there 28mm jets, So your timing could not be better, will look forward to seeing those hulls, will start saving pocket money the 540 sprint sounds interesting


Steve
Old 04-29-2013, 12:56 AM
  #4827  
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Default RE: The Unofficial all things Jet drive thread

Hi sundogz, my site is still 'under construction' (that's an understatement lol). Here's a link to a youtube vid from a customer in the states that is running the 4800kv on 3S setup, there's not so much slow acceleration though.... he's a bit of rev head lol. It should give you an idea of the speed though. https://www.youtube.com/watch?featur...3u49eaNrqKMThe flex shafts I make are impregnated with epoxy so they run really smoothly in the brass tube and the brass bush in the stator. You'll wear the impeller out long before you could wear out the shaft.Any vibration caused by shaft mis-alignment in a mechanical system causes friction and wastes energy with the result being that your motor is not reaching anything like it's kv rating. It is practically impossible to use a solid coupler to couple a motor and solid shaft without having a slight (at least) mis-alignment. Using a flex shaft significantly reduces mis-alignment induced vibration by functioning like 2 universal joints between the motor shaft and impeller shaft thereby allowing the smooth transmission of power even though the shafts aren't perfectly aligned.Another nasty side effect of vibration is that it creates turbulence in the water flow and makes the jet more prone to cavitation.So by using a flex shaft the motor revs much closer to it's kv rating. The pump is pushing more water through because the motor is able to spin it faster... therefore your boat goes significantly faster.I've sold hundreds of my modded jets, mod kits and flex/impellers and people swear by them. In fact I'm so confident that you'll notice a marked improvement that if anyone buys one of my jet mod kits and doesn't notice a significant difference I'll refund their money
Old 04-29-2013, 01:00 AM
  #4828  
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Default RE: The Unofficial all things Jet drive thread

No wuckers, keep an eye on this thread, as soon as the 540 is ready I'll post here. The small hull that takes the KMB 28mm jet fits my jet sprint 410 and is also an exact fit replacement for the NQD tear into hull... just cut away the original hull and silicon this one on
Old 04-29-2013, 05:52 AM
  #4829  
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Yes, I am waiting on a reply from a customer of yours that got real quiet after installing your 'system'. I described the video needed because running at WOT doesn't show the increase in speed like a slow wind up will. I have done extensive testing with this boat (look back through this thread) and jet and what you describe doesn't happen. After about (3000kv on 3S, - 4500kv on 2S) the jet reaches a point of deminishing returns and though it sounds faster, it isn't really going faster (but will sometimes spin the impeller on the shaft). Use a GPS and you'll see for yourself. You may be impressing upon some who haven't the time to read this whole thread, but not those who have been there. I have removed all vibration with good couplers (made by Jeff Wohlt) and it didn't affect the speed anything like you are implying. And even an epoxy coating won't hold up like a straight metal shaft in a bushing, and that can be proven too. And vibration has little to do with cavitation (I think you mean aeration) keeping your shaft bore greased will do more to that end. Sorry man, nothing personal, but none of that makes real sense. Make a movie as I described and you'll see for yourself. Nothing new here.
Old 04-29-2013, 04:00 PM
  #4830  
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Default RE: The Unofficial all things Jet drive thread

Sorry sundogz, I guess I didn't explain it very clearly in my last post, the problem is that if you dig too deeply into the hydrodynamics of water jet pumps it can become really dry reading.The essence of what I'm saying is that if you increase the actual RPM you'll increase thrust, the relationship between actual RPM and thrust is fairly linear. Vibration and friction absorb energy so you achieve less RPM and thrust. To increase RPM you can apply more power or reduce friction and vibration. The problem with going for more power is that to achieve it you have to use a bigger motor and or ESC and or battery, any and all of which will increase weight and excess weight is the mortal enemy of jet boats. Because the power to thrust relationship is very non-linear and the fact that jet boats are so weight sensitive going for more power can be counter productive, you're much better off making the system as efficient as possible.You're right in that vibration in and of itself doesn't cause cavitation, but in the stock NQD jet unit there's so much play between the shaft and it's bore that any misalignment in the motor/coupler/shaft causes the impeller to spin in a non-axial fashion (it wobbles). This causes the tolerance between the impeller blade tips and the tunnel wall to vary during rotation. When the tip moves away from the tunnel wall it creates relative low pressure cells which cause the cavitation. The tolerance between the trailing edges of the impeller blades and the leading edges of the stator blades is another area to look at, if the gap is too large you lose pressure and thrust but if it's too small it'll cause cavitation in the same way as a wobbling impeller. A worn stator bush is another major cause of cavitation because it too allows the impeller to spin out of true.Air ingestion is self explanatory and obviously unrelated to cavitation... BUT it has the same net result as cavitation... a loss of thrust, so it's just as undesirable. There's nothing you can do to stop air ingestion when your boat parts company with the water or when you're running in highly aerated water in rapids or the surf but if you experience sudden power loss on flat water then you're probably getting air ingestion caused by the poor tolerance between the stock shaft and bore. If you get any water seeping in through the impeller shaft bore then you can be sure that air is getting sucked into the jet unit.Running a flex shaft eliminates vibration but that's only one benefit it provides. The tolerance between it and the inside of the brass tube it runs in and the stator bush is negligible so the impeller runs extremely smoothly allowing it to operate very efficiently.It sounds like you've done a good job on your NQD and getting the drive train running smoothly is the single most important thing you can do but there are many other factors that need to be addressed to achieve the maximum performance from these little pumps. Building and improving these pumps and developing my jet sprint hull kit has been my full time job for over 2 years and as I've said, I've built hundreds of them, believe me I've tried it all and tweaked them in every way imaginable.Maybe the unnamed 'customer' you mentioned went real quiet because after installing my system he achieved the results he was after, one thing's for sure though, he's actually tried one
Old 04-29-2013, 07:46 PM
  #4831  
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Default RE: The Unofficial all things Jet drive thread

Steve, here's what I know, please correct me if i am wrong. A straight shaft with a balanced coupler will always induce less vibration than a flex shaft. Especially an unsupported flex. Your setup is unsupported from the pump body to the impeller. If there were opportunity for wobble, it would be with the flex shaft, not a straight shaft. So the flex cable would be a more likely cause of increased tolerances (stator to impeller, impeller to tunnel wall, etc) than the straight shaft. A bushing is not suitable support for the end of a flex cable. To remedy this you would need to install a straight 'prop' shaft on the end of the flex cable to reduce the friction, wobble and wear. You stated the relationship between RPM and thrust is linear, but a few sentences later you say "power to thrust relationship is very non-linear". Really? Power and thrust are one and the same in this scenario. We have done extensive testing ourselves and found the NQD jet can only pump so much water. You can apply more power, but it reaches a 'point of diminishing returns' and this happens at around 25KRPM's, or about 3000kv on a 3S system and 4500kv on a 2S (3000kv x 11.1 x 80% efficiency). What this means is it will go just so fast, and if pushed beyond that range, it will make more noise, but go no faster (but may cause the impeller to spin on the shaft!). To go faster you need a larger pump, not a larger 4800kv motor on 3S! That will only induce wear and make more noise (giving the impression of more speed) without actually going any faster. The diminishing returns effect can be observed on some Youtube videos. You'll notice the jump from a (quieter) throttle setting to WOT (wide open throttle) with little increase in traveling speed. That lower throttle was peak efficiency, any more is just wasting power and reducing runtime. But notice that most people run from slow to wide open (jumping past the mid range speeds entirely) making it difficult to observe this phenomena, but it occurs nonetheless.

To sum up:
1. A flex shaft cannot 'eliminate vibration'. It can only induce and mask vibration. If you have vibration, get a decent coupler. Don't try to drill out a smaller coupler to a larger size, it will almost never work and will only make things worse. If a flex appears to reduce vibration, then you have an alignment problem, and a flex will only mask the real problem, not fix it. And it will be robbing power while matching the two misaligned parts.
2. There is nothing inherently wrong with the bore tolerance in the NQD drive. Just keep the shaft bore lubed with a good marine waterproof grease and keep the coupler from rubbing the seal (spinning it and slinging grease out). Develop a schedule for re-greasing, re-apply more frequently if you have a high RPM system.
3. I don't need to try something to know it's not a good solution. Wisdom comes with making the mistakes and I have made my share, but I don't believe I'll be making this one. To each his own. I just don't like misinformation. To some people, the high pitched whine represents more speed, and there is your customer base. But some people will see past the rhetoric, and I am only too happy to help clear things up. G'dday, mate.
Old 04-29-2013, 09:28 PM
  #4832  
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Default RE: The Unofficial all things Jet drive thread

Hi Sundogz, I've attached some pics so you can see that the flex shaft is supported from the inside of the jet body behind the rubber seal right up to the back of the impeller. I don't know where you heard that the flex shaft in my setup is unsupported but as you can see, you're quite mistaken. The flex shaft in the brass tube is a much closer fit than the stock shaft in the stock unit and as my flex shaft is fully supported there is no vibration, whereas you will always get some vibration with a solid coupler and solid shaft because the motor shaft and impeller shaft will never be perfectly aligned. With my setup, at the motor end there is about 10mm of flex shaft between the inner end of the brass sleeve and the motor coupler, this 10mm length of flex cable is the only part that can 'flex' and it does so to negate any shaft misalignment thereby eliminating any vibration that would otherwise cause.I don't know why you would say that a brass bush is not suitable to support the end of a flex shaft when you haven't even seen one of my shafts let alone tried one. There is only about 5mm of flex shaft protruding from the back of the impeller and with the flex shaft being dipped in epoxy means that it's more like a steel reinforced epoxy shaft, so there is no discernible wear in the bush.Actual impeller RPM and the thrust of the jet unit are quite proportional. Power and thrust are not at all the same thing. In this scenario 'power' is what you are applying to the shaft from the motor whereas thrust is the amount of motive force generated at the jet units output nozzle.At lower RPM when you're operating well within the thrust envelope of the jet unit an extra 10% of power from the motor will give you something in the order of 7 or 8% increase in thrust. The point of diminishing returns you mentioned is the point where the power to thrust curve starts to flatten out and the extra power you apply gives you less and less added thrust and you quickly reach the point where you can double the amount of power applied and but only gain 10% additional thrust.The amount of additional thrust I get running a 4800kv on 3S motor is obviously not proportional to the increase in RPM but it is noticeable... because the entire drive train is running smoothly.In point 1 of your summary you say that a flex shaft can't reduce vibration... anyone who has used a flex shaft in any drive system will tell you that's exactly why they're used. I agree you should never try to rebore a coupler, I make mine from solid rod on a micro lathe to make sure they run true.As for your point 2, there is a great deal inherently wrong with the amount of tolerance in the stock NQD shaft and bore. It allows lateral movement of the shaft which is any mechanical system is extremely undesirable.And your point 3... hmmm.... not sure how you can say a system is no good without trying it... and your statement that the flex shaft in my system is unsupported and that a flex shaft can not reduce vibration are the only examples of misinformation I can find anywhere in this thread.Clearly we're just going to have to agree to disagree
Old 04-30-2013, 05:28 AM
  #4833  
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Default RE: The Unofficial all things Jet drive thread

Hi again Steve. You forgot to include pics and I still see none on your website. Maybe that's not a mistake. Let me clarify a few things - in no particular order. The primary 'reason for being' if you will, of a flex shaft is to bend. To go where a straight shaft will not go. Not to 'eliminate vibration' as you say. Of course if your straight shaft is bent, then a flex will vibrate less. But it will not 'eliminate the vibration' as stated on your site and here in this forum. A flex shaft used to correct misalignment problems is also robbing energy. A flex shaft that is 'supported' by a piece of tubing that is unsupported (sticking out of the pump body) is unsupported, nonetheless, and is inherently prone to vibration, movement and wear. When we speak of power and thrust, I hold that they are one and the same when connected by a solid shaft (as in this example). You apply power, you get thrust. But perhaps not if a 'flex' shaft is what is transmitting the power and there is a loss of energy from the motor to the impeller. Math: 4800kv x 11.1v = 53,280rpm's. That is more than twice the useful speed of the jet. All that can do is prematurely wear out components (so you can sell more?). Granted, I've addressed the fact that some people relate more noise with speed, but we both know that is not true. Now on to more important things: Do you hold a patent to your 'system'? Have you infringed on any copyrights with 'your' hull kit (it looks amazingly similar to Graupners Jet Sprint). Will you post pics of how your 'system' is installed and show how it is better? There is one thing I agree with here, and that is that we are in total disagreement of any 'benefits' your 'system' actually provide. Thanks for the 'lesson', I am always open to new ideas and concepts if they don't counter the laws of science. Again, G'dday.
Old 04-30-2013, 10:02 AM
  #4834  
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Default RE: The Unofficial all things Jet drive thread

I just wanted everyone to know that some couplers that I bought from Steve had evidently gotten lost in the mail. He was going to send some more, but I requested a refund, which he promptly took care of. Upon inspection, I find that these are high quality connectors. The length is good, the 3.17 end fits well and the 2.3 end (2.4?) is a little loose, but the three grub screws on the impeller shaft end will make balancing a snap. It is probably sized more for the flex mod that he offers. Anyways, I do recommend these couplers to anyone modding the jetboat with a larger motor. I have seen many offerings in the past several days of searching and found nothing that was as suitable. You cannot go wrong with his couplers. Sdg.
Old 04-30-2013, 02:23 PM
  #4835  
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Default RE: The Unofficial all things Jet drive thread


ORIGINAL: sundogz

Well it seems the couplers from SicRc got lost in the mail [] Isn't that the way it goes when you are waiting on something? Steve apologized for the inconvenience and will send replacements out Monday. I got the esc's and motors in, but the [link=http://www.hobbyking.com/hobbyking/store/__28223__HobbyKing_90A_Boat_ESC_4A_SBEC.html]esc's[/link] were just too heavy at 105 grams (I hadn't even thought about that!) Thought I'd try them since they are new to HK and I could use them with other projects as well. I've since ordered some [link=http://www.hobbyking.com/hobbyking/store/__7360__Turnigy_Marine_60A_Brushless_Boat_ESC.html]60A Turnigy's[/link] replacements from the HK USA location that are less than 1/3 the weight and can handle the load fine with the 380A burst current capability [X(] . Now am waiting on the couplers. I may try to find some locally since I use this size coupler (3.17 to 2.3) frequently in my builds.
Hi sundogz, when you get your 60amp esc check the water fittings. I didn't and killed it...

J
Old 04-30-2013, 03:21 PM
  #4836  
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Default RE: The Unofficial all things Jet drive thread

I don't know what happened to the pics, I uploaded them twice and the RCU system said they uploaded successfully. Don't expect to see much on my site (SicRC.com) like I said, it's under construction... hell it's still in the womb. If you want to see detailed pics of a NQD jet modded with my flex drive system have a look at the listing in my eBay shop (http://www.ebay.com.au/itm/170997743...84.m1555.l2649)Like the hooker said to the bishop... try it before you knock it It's no coincidence or secret that my boat looks similar to the Graupner Jet Sprint... NQD copied it to make the Tear Into and I copied the NQD. I made the hatch a lot bigger for easier access and added hatch bolts to give a better seal, added a spoiler at the back, an instrument console to the dash, made a thicker, stronger, more realistic looking roll cage and header pipes and one piece light weight molded heads for the driver and navigator. They also come in black, white or clear and you can mix and match colours.I think mine looks and is heaps better than either the Graupner or NQD... but I could be slightly biased
Old 05-01-2013, 06:59 AM
  #4837  
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Default RE: The Unofficial all things Jet drive thread


ORIGINAL: SkR8Pn
Hi sundogz, when you get your 60amp esc check the water fittings. I didn't and killed it...

J
Thanks J, I'll be sure to check for that! These Turnigy's are lighter that those new HK brand 90A esc's. The HK is listed as 105g and the Turnigy's 32g. I haven't weighed them (don't have a small scale) but they feel more like 2 to 1 (half) instead of 1/3. Nontheless, they will be an improvement for this 24" cat.
Old 05-01-2013, 08:31 PM
  #4838  
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Default RE: The Unofficial all things Jet drive thread


ORIGINAL: sundogz


Thanks J, I'll be sure to check for that! These Turnigy's are lighter that those new HK brand 90A esc's. The HK is listed as 105g and the Turnigy's 32g. I haven't weighed them (don't have a small scale) but they feel more like 2 to 1 (half) instead of 1/3. Nontheless, they will be an improvement for this 24'' cat.
No worries mate, I was disappointed that it bit it and HK was a bit of a run around to warranty it. It was the lightest that I've had to date for sure, I actually had to add weight to balance it out with the small lipo setup for rapids.

I'm keen to see the cat cranking with the jet drives. Are you going to use two micro servos with a Y harness or a link and single servo?
Old 05-02-2013, 07:14 AM
  #4839  
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Default RE: The Unofficial all things Jet drive thread

While the rest of the system is redundant, I decided on a single mini servo, a 'Y' harness and common linkage. No need to ask for trouble and I'm a fan of the KISS principle (keep it simple, stupid). I have intentions of eventually removing the steering altogether and going to thrust (vector) steering with a 2 stick TX control. I should have it all ready by this weekend. I am having second thoughts about the dual water lines. Each jet drive has it's own pickup which goes through holes in the transom and each will go to an esc - the motors won't have cooling (outrunners). So my 'dillemma' is that there is already a hole in the side for water out and I don't want to drill another hole in the hull. I'd prefer to have the water exit on top near the transom (jet ski style) it is so much easier to see. I've already expounded on the non-virtues of running two water lines together (Y fitting) and so don't like that idea. If you have a solution, let me know!!
Old 05-05-2013, 12:12 PM
  #4840  
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Default RE: The Unofficial all things Jet drive thread

I got more done on the JetCat. Tested it for leaks, were none. The Shoe Goo worked well. On the water cooling, I decided to keep the redundancy and ran two cooling systems. I drilled 2 more holes in the top for discharge (like a jet ski) so I can easily see if each side is cooling. And I patched the original hole in the side. I made a stainless bracket to hold the both esc’s on their sides. This made everything quite tidy, and all cooling lines are short and covered. The bracket is velcro’d to the tunnel, and the esc’s velcro’d to it, so that everything is removable if needed. The motor mount screw holes in the jet needed to be widened and I used a dremel tool to carefully do that. What a P.I.T.A, I should have done that before I installed the jets into the hull! (“note to self…). I drilled a hole in the transom so that I could to easily install/remove the motors using a long hex screwdriver. I used the steering boot hole to do that on the other side. I’ll just cover the hole with hull tape . Drilled another hole! and installed the antenna base with an o-ring seal. The receiver is velcro’d to the transom over the tunnel. The couplers from SicRc made it easy to connect the motors to the drives and everything is smooth and balanced. Now I need to program the esc’s and bench test everything. I will disable one of the esc’s bec by pulling a red wire on the ‘Y’ cable. Don’t want to burn up a bec (thanks, Steve). There’s a lot of room in the sponsons for moving the lipos to adjust the COG – your guess is as good as mine where that will end up being. I plan to use two Turnigy 2200mah 25C lipos unless run time is too short.
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Old 05-05-2013, 01:53 PM
  #4841  
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Default RE: The Unofficial all things Jet drive thread

That looks awesome, can't wait to see some vids! My only concern about building my twin KMB 28 powered PX16 is what's gonna happen when one jet gets a gob full of air and loses thrust. Just for a laugh I tried the PX16 stock and like nearly all NQD stuff it had 'vector steering'. Being a cat with that wide stance when you shut one motor off it really cranks a hard turn.When you trial it find the flattest piece of water you can and maybe start with the weight well back to keep the intakes firmly planted. I can imagine an impromptu pirouette being less than pretty (FYI, you won't get 12v going to the receiver and servo as the + and - are in parallel not in series in an ESC y-cable, the reason you need to disconnect the + lead on one of the ESCs is because it can damage the BEC circuits on the ESCs.)
Old 05-05-2013, 01:54 PM
  #4842  
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Default RE: The Unofficial all things Jet drive thread

Anyone have a link to the copy of the graupner mini jet?? The one in this post is dead....
ORIGINAL: sundogz

[link=http://www.ebay.com/itm/NQD-Tear-Into-Jet-Radio-Control-Boat-JET-Propeller-System-including-Steering-/320763070471?pt=Radio_Control_Vehicles&hash=item4a aef80807]Click here[/link] for a link to a replacement NQD jet drive that is virtually a copy of the graupner mini. When used with [link=http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=8594]this 28mm motor[/link] it really screams.
Old 05-05-2013, 03:11 PM
  #4843  
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Default RE: The Unofficial all things Jet drive thread

Hi j, I have plenty of the stock NQD jet units, they're $35 air mailed world wide. I also have modded ones for $55 delivered. The more you get the cheaper they coz the postage from down under is almost as much as the jet unit so if you have any mates that are into 'em then happy days
Old 05-05-2013, 05:09 PM
  #4844  
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Default RE: The Unofficial all things Jet drive thread


ORIGINAL: SicRC
My only concern about building my twin KMB 28 powered PX16 is what's gonna happen when one jet gets a gob full of air and loses thrust.
Have you had any reservations about the P16 being a stepped hull? This is just speculation, but are you concerned that the froth caused by the stepped hull might induce aeration at high speeds? It's for this reason that I looked so long for a non-stepped hull to use for a jet conversion.
Old 05-05-2013, 05:23 PM
  #4845  
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Default RE: The Unofficial all things Jet drive thread

Won't know 'til I try but I'm not expecting it to be a problem... and if it is I'll have an excuse to but a sexy glass cat hull I'm looking at the one from R2hobbies, cheap and looks nice, looks a lot like what you've got there.
Old 05-05-2013, 10:25 PM
  #4846  
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Default RE: The Unofficial all things Jet drive thread

Glad to here there are plenty of spares available, no doubt gonna be needing them.

Can you explain the advantages of the modified one anso does it drop straight in?.

I see what you mean with postage as that comes out about £36 pound for the modified jet.



ORIGINAL: SicRC

Hi j, I have plenty of the stock NQD jet units, they're $35 air mailed world wide. I also have modded ones for $55 delivered. The more you get the cheaper they coz the postage from down under is almost as much as the jet unit so if you have any mates that are into 'em then happy days
Old 05-05-2013, 11:14 PM
  #4847  
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Default RE: The Unofficial all things Jet drive thread

The modified one has a brass sleeve and runs a flex shaft, a stainless intake grill, integrated water pick-up and it comes with a precision motor coupler to suit whatever size motor shaft you are running.The benefit of the flex shaft is that it's a snug fit in the brass sleeve so there's no play. The outer winding of the flex shaft acts as a screw pump which, combined with the snug fit means that there's no water ingress through the shaft bore. The flex shaft is exposed between the motor coupler and where it enters the jet body, this allows it to act like a double universal joint and compensate for any misalignment between the motor and drive shaft so you get maximum energy transfer from the motor to the impeller.It will drop straight into the NQD hull as it is a genuine NQD unit that I've modified.Here's a link to the listing for it in my eBay store where you can see some detailed pics (http://www.ebay.com.au/itm/Modified-...item27d04280f5)
Old 05-05-2013, 11:48 PM
  #4848  
jtheg
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Default RE: The Unofficial all things Jet drive thread

Thanks for the quick reply mate!

If I purchase a modified jet what motor, esc and batts would you recommend running??? Dont what it insane speed would rather reliability to keep my son happy!!!


cheers.


ORIGINAL: SicRC

The modified one has a brass sleeve and runs a flex shaft, a stainless intake grill, integrated water pick-up and it comes with a precision motor coupler to suit whatever size motor shaft you are running.The benefit of the flex shaft is that it's a snug fit in the brass sleeve so there's no play. The outer winding of the flex shaft acts as a screw pump which, combined with the snug fit means that there's no water ingress through the shaft bore. The flex shaft is exposed between the motor coupler and where it enters the jet body, this allows it to act like a double universal joint and compensate for any misalignment between the motor and drive shaft so you get maximum energy transfer from the motor to the impeller.It will drop straight into the NQD hull as it is a genuine NQD unit that I've modified.Here's a link to the listing for it in my eBay store where you can see some detailed pics (http://www.ebay.com.au/itm/Modified-...item27d04280f5)
Old 05-06-2013, 12:41 AM
  #4849  
SicRC
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Default RE: The Unofficial all things Jet drive thread

If it's for your boy then yeah, keep the speed down and the run time up. You can't go past hobbyking for value and once you've done the research and know what's good there the quality is good too, I just checked and they have these items in stock in the UK warehouse.MOTOR: http://www.hobbyking.com/hobbyking/s...=34446BATTERY: http://www.hobbyking.com/hobbyking/s...trSearch=zippy compact 2s 2200ESC: http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=28712That'll give you a really sweet setup that's still and zippy but will still give good run times.Make sure that you disassemble the ESC and put some silicone in the joints to make it as watertight as possible, then put it inside a balloon with a cable tie around the neck.The outrunner motor will require a cooling disc to stop the front bearing from overheating, I have them for $10 and I'll chuck in some long mounting screws that you'll need.When you're ready just private message me your email address and I can send you a paypal invoice.Cheers, Steve.
Old 05-06-2013, 12:56 AM
  #4850  
jtheg
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Default RE: The Unofficial all things Jet drive thread

Now thats what i call some good service cheers for the info much appreciated!!!!

What do you think about adding trim tabs??


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