ryanwilson277

i dont have a grate yet either

damfurst

I took a 3mmX10mmX4 bearing (the same one that can be used in the graupner mini jet drive) and sleeved it with a brass bushing made from 1/8" so that the 2.3mm shaft would fit it. I think I had to turn down the outside of the bushing a little to get a snug fit in the bearing. I did this to two of these drives and though neither have alot of time on them, it so far has worked well.
You can see in the pic with them installed in the drives.

richdb77

Maybe a silly question but bear with me.

I have a 35A water colled ESC and was planning on running a 11.1v 2200Mah lipo battery. However this has failed to show (dodgy fleabay seller) and its got me thinking that maybe 2200Mah is too high Amp wise for my ESC?

If so is 800Mah better (lower peak Amps) ?Whats the run time like on 800Mah?

Sorry if its very obvious.

sundogz

A larger battery won't have any bad effects on the esc - in fact, it will provide more amps when the esc calls for it. 2200mah is fine for that boat. In fact, you can double that if you want. If you have problems with priming, the added weight will help.

sundogz

And this is without a grate? Must be what Damfurst was eluding to - an enlarged shaft hole at the rubber bushing area. You might need to bush it to fix.

DRAGONFIRE81M

yep after you remove your motor try to move the shaft up and down side to side if there is any movement your probly sucking air and loseing prime that away . you need to put a 1/8 wall brass tubeing in to shim it back out . if its the stock drive .

sundogz

PM, you'd be better served with a Graupner mini in that boat, so you can obtain spare impellers. If it is a worn shaft area causing aeration (priming problems), you might try Grim Racer Speed Grease. It is thick, waterproof and will stay put. It should fix that if it's not crazy worn out. In fact, it is so viscous it will bog down a flex cable drive if you pack it in. Sdg

ryanwilson277

i think that might be the problem because after i run the boat i bring it in and slowly run it with the top off and water gets flung around off the coupler, just a little bit, so im gonna do what you said but i still dont understand how to do it. sorry lol

wrangellboy

I broke my impeller on the stock jet pump this weekend. Now I'm torn about what to do. There don't seem to be any really great options for finding a replacement impeller. Any advice on which of these is the best option?

1. Buy another NDQ and just tear the jet drive out of it.
2. Buy the small graupner jet pump and put it in (Costs more than a new boat with drive...)
3. Buy the 29mm graupner pump and go crazy with it.
4. Try to hack a graupner impeller into the nqd pump.

#3 sounds fun but I take the boat camping with me so I shoot for simple and reliable, which I suspect this beast would not be. It's also likely to be far more work. I like the idea of the bigger pump though because I'm hoping it will lose prime a lot less. My stock pump was practically useless on anything but calm water due to losing prime, and what's the point of a jet boat that can't do rapids?

Any Advice?

sundogz

Cheapest fix is to buy another boat($43 [link=http://cgi.ebay.com/New-Remote-Control-Electric-Air-Jet-Racing-Boat-R-C-RTR-/250649602369?cmd=ViewItem&pt=Radio_Control_Vehicles&hash=item3a5be16941]delivered)[/link]. Then do a clean cut and remove of the hatch, remove the jet drive and then sell the hull on ebay to recover some cost.


Next would be to buy a Graupner mini impeller and a 2.3 to 3mm coupling. Then drill out the shaft hole and the rear bushing to 3mm. Be sure to lube before use. When that shaft hole wears out later, bush it with brass tubing.

I'm not a fan of turning down props for this job. Sdg

llDemonll

buy a new boat and a 29mm graupner drive =)



also, do NOT run big batteries. Yes, the ESC could handle them, but both eTokyoPop and I burnt up a 2040 3200kv walkera motor in less than 1 run using the 3000mah 3s 20c batteries we had originally ordered. We think it was because of all the weight they carried, but arent sure.

sundogz

That wasn't the batterys' fault. The battery will give the motor just what it asks for. And it will ask for more when in a bind. When the Walkera motor is supplied with sufficient amps it can really haul, and will create a lot of heat because it is almost borderline on the power scale. So it's my guess that was because of improper cooling. Tubing won't cool the Walkera motor sufficiently, even with heatsink compound. You need to use a full length water jacket on that motor, and be sure there is adequate flow available (shooting out a little stream).

The smaller battery won't supply enough for it to reach that level, so no worries there except maybe puffing a low C (cheap) battery.

llDemonll

yea, still no idea how electronics work lol

we have been looking for full-length water-jackets though, tough to come by. temped to talk around to some friends and get them custom-milled with a larger "reservoir" around the motor to hold water for a longer period of time..would seem more efficient to me

wparsons

If the motor is burning up from too much current, going to a smaller battery will just make the battery the weak link.  The only way to properly fix a motor drawing too much current is to get a beefier motor, or smaller/less pitched prop, or give better cooling.

I've got my boat in pieces already, partially ready to be re-assembled.  Hopefully it'll get the base coat of paint tonight so I can get it back together for the weekend!

pmdevlin

Guys,
can you just go over that sucking air thing again please?
do you mean that the plastic hole in the drive that the shaft goes through gets worn? but the 2.3mm shaft isnt that tight a fit, so how is it getting worn, and with the coupler and rubber bush fitted, where is the air coming from?
just curious about this, I have just removed the grate and stator guard mod, fitted 3 small carbon rods in the intake to act as garbage protectors. I was thinking the grate and stator protector plate where the cause of real bad loss of prime on the slightest of choppy water

sundogz

Yes, that is what Damfurst was talking about. The hole the shaft goes through wallows out after a while with high rpm's (stainless and plastic not being the same hardness). It will suck air thru this shaft bore when you lose prime and make it harder to pick up water. Early on (maybe what you're experiencing) you can fix it by lubing with a thick waterproof grease (like Grim Racer synthetic grease). That should stop it from sucking air until it throws and needs reapplication or until it wallows out further in which case try the above methods. A brass tubing liner will last longest and you can fit a replaceable Graupner impeller. The rubber seal is just to keep the grease in, not water and air out. You can get fancy and fit a means to lubricate (small tubing) the shaft more easily. Sdg

wparsons

What diameter tubing is anyone using for the liner?  I can't find anything except 1/8" or 3/32" O.D. tubing, neither of which fit.  The 1/8" fits over the shaft but has a bit of play, it is less than my pump has stock in the plastic though, so I'm tempted to just use it.

DRAGONFIRE81M

i used 1/8 but i had to drill out the hole in the intake to 1/8 . i also ran the brass all the way to the impeller

wparsons

^^ I'll have to drill out the intake to fit the tube, I just wanted to see if anyone found tubing that was a tighter fit.  I'm definitely going to run brass all the way to the impeller to keep it from moving around .

bustitup

My Feedback: (7)

anyone have one of these available

Turnigy 2836 Brushless EDF Motor 3200kv

sundogz

Heres the [link=http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=8138&Product_Name=Turnigy_2836_Brushless_EDF_Motor_3200 kv]link[/link]

bustitup

My Feedback: (7)

Ya those are on back order

wparsons

Not that its a huge help because its out of stock too, but this is the one I ordered:

http://www.hobbycity.com/hobbycity/s...dProduct=11173

Same size and kv, should be a comparable replacement. It's a little down on wattage, and max voltage but will still be plenty powerful on 3s.

bustitup

My Feedback: (7)

yup I like that one too....i'm going to use this till those become available....i'm going to have to run it on the only 2s I own.........xps 2s 5000mah 30c...i figur the boat can use the extra weight...lol

http://cgi.ebay.com/KV-3700-Brushles...22980819534754

ryanwilson277

i got 1/08 i think , brass tubing, it fits the best