NorCalZ71

just curious if the abc hobby drives are still available anywhere? i was going to order a duck drive but i didnt realize its smaller then my tear into drive.... still might order a few.

Nighthawk117

My Feedback: (41)

Sundogz, my son found your jetski vids online and to make a long story short we have two Abc hobby jet skis ! What was the final outcome, best upgrade for 7.2 nimh or lip setups ? I am a total boat noob, but we have all the other various surface and air RC's. Could you pm me the info, or post it here , I have been searching this thread and there is a lot of info here !! Looking for basically a bolt in mod if possible ? Thanks.

sundogz

So far the fastest, most reliable system is [link=http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=8594]this[/link] 3900kv motor from HK, a water cooled 60A esc (Seaking, Turnigy) and a 2500mah 30C 2S battery (Nanotech, Rhino, Zippy, etc). You'll need an [link=http://cgi.ebay.com/Axial-AX10-Scorpion-28mm-Brushless-Motor-Plate-/400201704196?pt=Radio_Control_Parts_Accessories&hash=item5d2de16304]adapter[/link] and a 3mm to 3.17mm coupler (I had some made up by [link=http://www.rcraceboat.com/]Jeff Wohlt[/link]). This works fine with a 5000mah lipo for longer runtime, but we are getting 15 minute? runtimes on the smaller lipos when all is right and well. Look up my mod to the rear on the intake ramp if you encounter cavitation.

ISIRC10

This weekend I took the jetboat out to test my new impellor setup and it turned out to be a very bad day for me. It wasn't that hot, only 95 according to the thermometer at the dock. I setup my stuff on the deck our full size jet boat (I had done this in many outings before) and after a short run (setscrew backed out) I brought the boat in to check temps - they were all reasonable and the boat was running better then it did with the plastic impellor (less cavitation and vibrations). Speed was identical although acceleration seemed a tad slower. Anyway, I finished the first run and charged up the battery - It was in plain sight the entire time i was charging, but when I unhooked the pack, the charger let out a wisp or two of smoke. Crap! It hasn't turned on since then so the consensus is that the heat took it down - I could not hold the darn thing it was so hot. Discouraged, I put the charger away and ran the boat again - after another satisfying run I put the boat on the deck and went swimming. The boat, being painted black, heated up to the point where the paint started bubbling off and the ride pad at the bottom of the hull warped to resemble the rocky mountains. So yeah... right now I am contemplating sanding all of the crap off the hull and using it as a plug for a fiber glass hull and then transferring the electronics. I also need to sell one of my r/c's to get money for a new charger - I need one to charge my lipos!

Anyways, sorry for the rant, I had a bad day (well, for R/Cs at least) I did not let this ruin the rest if it, but now that I have slept on it this does throw a wrench into the spokes.

grael

Sorry to hear about your roasting issues ISIRC10, we're in the middle of winter here in New Zealand, so I'm having problems at work with plastic being brittle ! I'll remember this though, my PETG boats don't need too much heat to mould, so I have visions now of coming back to the car and finding a black painted boat pancaked!

I use this charger:<meta http-equiv="content-type" content="text/html; charset=utf-8" />http://www.hobbyking.com/hobbyking/s...dProduct=12104
and this power supply:<meta http-equiv="content-type" content="text/html; charset=utf-8" />http://www.hobbyking.com/hobbyking/s...dProduct=13765

orangewheels01

will do, will let you know how i get on when the motor arrives, many thanks for your help

sundogz

ISIRC10, I have a balance charger that works well except it will no longer discharge batteries. You are welcome to it . PM me your shipping address, I can get it shipped tomorrow.

ISIRC10

Yeah, I looked at that charger but there were a decent amount of negative comlaints - I am currently contemplating this one:
www.hobbyking.com/hobbyking/store/uh_viewItem.asp

I know it is expensive, but its reviews are good and it is easy to callibrate - plus I am getting more and more 4s-6s packs that need to be charged faster so I hope that this charger lasts me a few years. In terms of power supply, I don't care for Hobby Kings offerings - it seems most are flawed and overpriced. I buy computer PS from here:
www.e-techsiliconvalley.com/store/index.php
and then convert them to desktop power supplies. I can get 500W for about $30 and 30 minutes of tinkering.
</meta></meta>

grael

I Hadn't thought of that... should have though, I have one driving my much neglected CNC PCB design.Link the green and black wires from memory to power up...My charger's worked great so far.

ISIRC10

Yep, green and black are the power switch, and depending on your PS, maybe put a 2-3 amp load on the 5v line to bring up the amps on the 12v lines. I have done it a few times and all have been sucessful - It really is amazing how much money you can save per watt over the commercial "rc charger specific" PS units.

RandyatBBY

I found some time to finish the setup in the Runner bottom boat this weekend. Wife was gone hiking.

The top view lay out.


I had to build a special coupler the mate the 3MM shaft to the .125 motor shaft and have the correct distance between the two.


The full layout


The business end little jet drive. I will be adding trim tabs and angle the jet nozzle down a little.


Uploaded with ImageShack.us

sundogz

I was thinking about your boat the other day - wondered if you had finished it. I'm guessing that it is porpoising or hopping some and that is why you want trim tabs. I'd hold off on changing the angle of the drive until you try the tabs. They usually do the trick. How is it doing as far as cavitation is concerned? Are you going to make a video so we can drool over it? Thanks for updating this Randy - looking forward to a video.

RandyatBBY

I will be painting it soon. I have ran it two times the first time the coupler was a real problem and it took off great then it cavitated for a moment then the coupler gave out. I took the 5000kv motor out and put in a 4200kv Lehener in with a custom coupler and went to the pond again. This time it was late and cold but the boat ran fine, with a little porpoising. Just lightly. I wanted more speed but the cavitation was gone. I was thinking it would be faster with out the trim tabs and point the thrust down to solve both problems, speed and porpoising. Other wise I love it. it ran dry. Now we need speed and paint something wild.

areseaer

Nice boat Randy, can't wait for a vid.

one more boat from many pages ago


[youtube]http://www.youtube.com/watch?v=kjwitCu2TuA[/youtube]


This is only 2s with a 1520 1600kv castle motor. bent the jet's shaft with some cheap couplings so it vibrates to much on 3s. Will fix it soon.

HB2Flyer

My Feedback: (4)

Randy, Great to hear you got your boat running. Will you be out at the pond this Sunday? I will bring my drag jet for another try. I made the mods we discuss to the bottom and will try it on 4s instead of 6s. Maybe mine will go faster then 10mph this time.

Rich

Nighthawk117

My Feedback: (41)

Thanks for the info, is there another manufacturer with this motor/esc combo? Seems like these are still out of stock and it's been a while ?

sundogz

Try [link=http://www.nitrorcx.com/07e-c-sl-10t-2848-blue.html]here[/link] and [link=http://www.hobbypartz.com/07e-c-sl-10t-2848-blue.html]here.[/link] They had some in stock the last time I checked.

RandyatBBY

Had the drag Runner hull out and got a video, enjoy

sundogz

Lookin' nice! Respectable speed too. Did you have to install trim tabs (cav plate) or put negative angle on the nozzle to tame it? You made a good looking hull, to be sure. I like that drag boat style or look to it.

LesterRienhart

Hey guys,

I had a Jet boat project in mind, but when I looked for the Graupner Jet drives I found out to my dismay that they are all now discontinued. Is there another manufacturer of small model jet drives anyone can recommend?

The boat I wanted to build is only about 18 inches long(I'd have to look at the plans again), but I wanted it to hit really hard off the bottom. Enough to backflip off a small wake with trim.

Any suggestions would be awesome.

Thanks!

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=item4aaef80807]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.

LesterRienhart

Thank you!

jezzahealy

I am currently scratching building a 13" replica of a Fairey Huntress to resemble the one used in the James Bond Film "From Rusia with Love". I am experimenting with a Graupner mini-jet.

On seeing the above links, I ordered a couple of NQD drives, for my next project idea. I plan on making a replica of a Levi Corsair with twin jets, possibly around 20" long. The two jets arrived yesterday and my first impressions are good value for money but not as strong as the Graupner drive as it has some flex in it towards to motor mount. The other observation is that they have been supplied without the rear base plate which picks the water up into the impeller. Is this correct? They have the little holes at the front for the grill wires like the Graupner but nowhere to locate them at the rear. Do you have to make your own?

My first idea was to use one 540 size brushless motor to drive both via gears, but fear it is overly complex and won't be as effecient as seperate smaller motors, any thoughts? Secondly if I use seperate brushless (sensorless) motors do I need two ESCs or will one larger one work. I know with brushed motors you can use one but will it work with two brushless motors?

sundogz

The intake ramp/grill should have been with the jet drives - it must have been an oversight. It would be fine to use a geared setup. If you use two motors, you should use a separate esc for each brushless motor (unlike for brushed where one esc can suffice). There were experiments with two motors on one esc, and while it did run both (with some complications), it never made it past the bench stage.

jezzahealy

Thank you Sundogz for your reply.

I have contacted the ebay vendor and have been assured that the inlet ramps will be sent on.

I thought that was the case with brushless motors, but just wanted reasurance. I have been looking for a source of gears with 3/3.2MM centres and have had no joy so far. Two brushless motors may be the way to go.