RE: Unofficial "NQD" Tear into Jetboat Thread
 

Thanks for the input head and dragon. The other reason I replaced with the graupner is I wanted to build a mini jet v like dragon and thought that the nqd one would fit better with it already set up for a 380-400 size motor. Since my last message I went to a 9.6v a123 battery and wow what a difference. I know from all the other threads that you guys run more 2s-3s lipos, but I think I'll stick to this set up as it works well for me. Need to fine tune some of it though. Anyway keep jetting>

dam

RE: Unofficial "NQD" Tear into Jetboat Thread
 

yeah that drive is a little lighter then the grupner drive and you wont have to make an adapter . like i said once before i would love to see a nother mini-jet-v :D

RE: Unofficial "NQD" Tear into Jetboat Thread
 

Hi all, Just wondering if cavitation is as much a problem for you all or not. It seems like if I turn just right or hit waves at the right angle there goes the prime and all control. I do have the bars on the graupner jet I have in my nqd and wondered if removing them would solve part of this problem. My set up is quite heavy but losing prime still happens. I also wondered if building some kind of water ram for the intake would be an option and if any of you have tried that. Thanks, Dam

RE: Unofficial "NQD" Tear into Jetboat Thread
 

Dam you have a pick of your intake? Maybe some pics inside too? What kind of water are you running?

RE: Unofficial "NQD" Tear into Jetboat Thread
 

i think after reading this and watching the youtube vids i am going to buy one of these. a couple of questions: what kv motor should i get? i have a quark 33, spektrum M8 radio and reciever, 11.1 lipo. i want it to be a fast rapid runner in the creeks around my place. second question what servo is recomended and will i have to make a servo mount. i can make the mount is weight an issue with the material or can i cut some alluminum and go?

lovin this smaller jet thread that other thread is out of control.

thanks guys this will be my first boat build, i am an 18th scale offroad buy and crawler.

RE: Unofficial "NQD" Tear into Jetboat Thread
 

You can use any servo you want, my buddy swears by the big heavy servo, me I go with a small light 5gram servo. For mount, just get a small piece of aluminum angle, notch out where servo sits.

http://www.rcuniverse.com/forum/m_65...tm.htm#7031632 for ultra light servo mount
http://www.rcuniverse.com/forum/m_65...2Cmount/tm.htm for heavier duty servo mount.

Have had really really good luck with this motor(3 boats), others have tried 3200-3600rpm/kv shoot for 30-40amps
http://www.unitedhobbies.com/UNITEDH...idProduct=4200
combo'd with this esc
http://www.unitedhobbies.com/UNITEDH...idProduct=6318
but requires programmer card
http://www.unitedhobbies.com/UNITEDH...idProduct=5448

haven't had luck on the turnigy esc though... although my motor could just be bad.

Ummmm... you'll want to sleve the shaft at some point or drill it out larger and add a bearing where the rubber grommet is, as the shaft sits in plastic protected by grease which doesn't last too long. (wasn't designed for high rpm).

With that motor I posted, on 7.4v it pulls 23 amps, on 11.1v it pulls 30 amps. Add cooling lines to the motor and one or two to the esc(merely by gooping in some aluminum tubing against cooling that's already there.

Other tips, when cutting top to get to the electronics out and replace, leave the posts! leave like a half inch around the top so you can add some foam or gasket to keep water out. Also the decorative engine tips need to be pulled off and siliconed or gooped. Ummm... very thin carbon fibre rods make great grills, just notch in the plastic then goop/epoxy. Uh... make sure you get all the glue out, it's heavy. You'll have to mess with cg once done, once you get cg right, boat works really really well and helps prevent loss of prime going up river.

That's about all i can think of... oh batt, you can go 4400mah with this setup perhaps more. Have tried both 11.1v and 7.4v with this amount of juice.

Ivan.

RE: Unofficial "NQD" Tear into Jetboat Thread
 

I just bought one of these things for my christmas present. I took it out stock christmas morning and the performance was lacking but I expected that . I am just happy that it works. I'm going to try a 3200kv motor with a 2s lipo and see if that makes it do what I want. I'm just running little creeks.
MikeV

RE: Unofficial "NQD" Tear into Jetboat Thread
 

I got it running with the bl motor/lipo and it was great. Until I broke the impeller. Anybody know how to get parts? I did contact the seller, am waiting for a response.
Thanks
MikeV

RE: Unofficial "NQD" Tear into Jetboat Thread
 

Quicker and cheaper would be to get prop from hobby store and throw on high speed drill or lathe, then put a file to it till it's the size you need. Take your time. If your doing an octura, make sure you have a good mask, the whateverberilium is highly toxic, will not come out of your system. The second more likely option is to get graupner mini jet prop and shaft replacement, drill out old and sleeve in a brass tubing as you'll need to do it anyways at some point.

Ivan.

RE: Unofficial "NQD" Tear into Jetboat Thread
 

headhunter is right. your not going to get replacement parts nqd doesnt even offer them on there site . i would do the grumpner impeller b/c its the easest to do . or you can get a prop form ose . ill post a link to both .

http://www.cornwallmodelboats.co.uk/...upner_jet.html look at the bottom at the 19mm grupner impeller

http://www.offshoreelectrics.com/pro...od=grp-2318.26 this is the prop i cut down and used in my nockoff drive

http://www.rcuniverse.com/forum/m_65...37/key_/tm.htm



these two are of headhunters metal 1/8 shaft converson
http://www.rcuniverse.com/forum/m_65...25/key_/tm.htm
http://www.rcuniverse.com/forum/m_65...27/key_/tm.htm

RE: Unofficial "NQD" Tear into Jetboat Thread
 

Thanks,
I just ordered some graupner ones from cornwall.
Mikev

RE: Unofficial "NQD" Tear into Jetboat Thread
 

Just a little update on my nqd boat. I had sucked up a rock last year and broke my impeller. I tried using a turned down abc hobby impeller for their jet ski. It did not perform as well, so I changed my motor to a higher torque motor. Still it seemed to cavitate more plus it took out the graupner ujoint. Replaced that with an all metal one from the apache. I finally gave up and put a replacement impeller from cornwall boats in the drive & it runs just like it did before i sucked the rock up. Below r some pics of turned down impeller set up and u joint.

RE: Unofficial "NQD" Tear into Jetboat Thread
 

man thats some cornage on that u-joint . but im glade cornwell came through for you and get you going again :D

RE: Unofficial "NQD" Tear into Jetboat Thread
 

I didn't have much success with my first one so I gave it to a friend. But I bought a second one to try some things on. First off this one had a solid metal connector from motor to drive shaft and the first one had a plastic u joint. The second one wouldn't even spin by hand because the outlet tube was out of round and the impeller was stuck. I found that the head of a mini mag flashlight was the right size to form the outlet back to it's proper shape. The cut out for the jet wasn't big enough so when i tried to put it back in it warped it. So a little dremmeling and it all fits. I used a bushing from a small motor with 2mm shaft to support the front of the drive shaft and decided to use a little 3000kv outrunner motor and esc from ebay to power it. Well it works real well. I've run 2s lipo at first to see how it does and then switched to 3s. With a 2200mah battery I get a very long run time and it is way faster than it needs to be. I've wanted a jet boat for a while and want to thank you guys for this thread.
MikeV

RE: Unofficial "NQD" Tear into Jetboat Thread
 

Sounds great, post some pics if you can. Yeah, I do mostly river/creek running myself and recently upgraded from a 2100 to a 3800KV (w/3s), so I should have no problems in the frothy stuff (if the impeller can handle it). I am a believer in higher volts=lower amps=longer run times with lower heat and am running Mystery 3s 2800ma 20C Lipos.

My metal shaft connector has oversized holes and causes vibration; I plan to change that for sure. And my impeller bushing wasn't even in the hole (butted against it) so I also had to redo that. Does your outrunner have an outer (non-moving) case? If not, it makes it difficult to cool effectively, and you might want to go to an inrunner/cooling tube/jacket if you end up cooking the present one.

For *****s and grins I changed the drivers heads to some I found on an an 'animated lowrider' toy (they already had a 'curve' in the neck area) and I left some wobble when fastening, so when you take off or turn, their heads move that way (whiplash). Here are some pics:

RE: Unofficial "NQD" Tear into Jetboat Thread
 

Damfurst, I hadn't been monitoring this thread but am glad I checked - this is great info. Is that the 29mm impeller from graupner? I know the impeller from the Jet Ski is way thin and vulnerable.

And wow! did you see this? [link]http://www.cornwallmodelboats.co.uk/acatalog/graupner_2395.html[/link]. Looks like they moved the intake all the way to the transom (like I modded my Jet Ski). No more cavitating due to too fast speed in some hull designs. This really opens up possibilities.

I'm thinking of using a Graupner reverse bucket on my Jet Ski. It isn't heavy enough in the rear to keep the parts in the water and I don't want to add weight to accomplish that. Wonder which one would fit best. Has anyone done that yet?

RE: Unofficial "NQD" Tear into Jetboat Thread
 

Hey Sundogz, the impeller is the 22mm from the jet ski. I could not get it to stop cavitating so put the graupner one back in. I think I may have to open up the intake like you did in order to get enough volume of water to supply it. I'm trying to install the purple 2700kv motor in the knock off right now. I'll have to show a picture if it works. I may try to put my turned down impeller back in too. I'm not going to give up yet on it.

Have you tried a brushless motor in your jet ski? If so what did you use? I just tried one in mine & I smoked it brand new motor. It's the same one thats in my mini-v(aka the brick). Kind of puzzling. The motor temp was like 220 f. I didn't have water cooling on it-probably should have. Oh well live and learn.

RE: Unofficial "NQD" Tear into Jetboat Thread
 

So is the Graupner one a 29mm turned down to 22 or is it the 19mm for the mini jet? I'm confused. No, I haven't seen the need for a brushless in the jet ski - the 550 brushed can handle 3s easily and is quite fast (brushed type esc of course). Yup, 200 degrees will fry a motor for sure. Gotta cool that puppy down!

I saw a movie on youtube of a Kaw Jet Ski with a Mamba brushless setup. Was too much for that impeller/intake and cavitated right away. The original 550 can take a lot of voltage - I don't know the limit yet but have used up to 12v (was nicad) so far with no hitches. And quite speedy! Been using 8c routinely and get lots of playtime and spunk.

RE: Unofficial "NQD" Tear into Jetboat Thread
 

Ok the Graupner one is the 19mm replacement one that I got from CMB(Cornwall Model Boats). When I put it back in the jet drive worked perfectly again. The impeller I turned down from 22mm to 19mm was the abc hobby one for the jet ski. Hope that clears things up.

My jet ski 550 motor burned up, so that's why I tried the brushless one. Wish I had had cooling on it, but I don't know if that would have saved it either. Guess I'll go back to a 550 size or even a graupner 600 motor since I have one of those laying around.

RE: Unofficial "NQD" Tear into Jetboat Thread
 

Yeah, thanks for clearing that up! And glad to know you can use the Graupner mini jet impeller as a replacement for the NQD jet units. I had read it was smaller. Now you might consider doing my intake mod. Less hassel, more fun.

Was that the brushed 550 motor that burned up? How did that happen? I haven’t had problems with mine yet (knock on wood). That Graupner 600 should do nicely.

RE: Unofficial "NQD" Tear into Jetboat Thread
 

I think the props are same size(graupner mini jet vs knock off), shaft size for knock off is smaller though for sure.

Ivan.

RE: Unofficial "NQD" Tear into Jetboat Thread
 

it was me that miced the first run on both and fond that the nqd was 20mm and the graupner was 19mm but that could have been off . but the shaft are diff like head said there nqd 2mm and graupner 3mm . the funny thing is im now working on putting the graupner impeller in to the nqd drive and useing the roller bearing mod . plus im dropping in the 2900 kv motor and 30a esc that was in my other hull . plus i was looking on the graupner web site . and i thank there offering the jet sprint hull for $56 but im haveing truble reading gurman . any help there its Satz Tiefziehteile

RE: Unofficial "NQD" Tear into Jetboat Thread
 

well its done . the roller bearing slide right in and just had to drill the 2mm bushing in the stater nozzle to 3mm . pretty easy thank ill order some 19mm graupner impeller

RE: Unofficial "NQD" Tear into Jetboat Thread
 

Damfurst, take a look at these. [link]http://cgi.ebay.com/2-NEW-JOHNSON-F-C-550-FAST-MOTORS-3-12-VDC-24K-RPM_W0QQitemZ300295194717QQihZ020QQcategoryZ2564QQ ssPageNameZWDVWQQrdZ1QQcmdZViewItem[/link]They look like good cheap candidates for the jet ski. The same seller has some larger motors as well.

RE: Unofficial "NQD" Tear into Jetboat Thread
 

Vague memory but i think it was 2.3mm shaft.