DRAGONFIRE81M

i mailed the guy asking for some set up shots and how his running to drives with eather 1or2 motor set up. maybe he will respond . heres a link http://www.rcuniverse.com/forum/m_62...tm.htm#6275803
on the sponsons no i havent seen any one do it dut i did add skirts to the botom like channel runner to help with the problem of always doing a 180 when it plained out . that part is in this thread

DRAGONFIRE81M

found the hull heres a link http://www.jet-drive.de/cms/componen...,42/Itemid,17/

DRAGONFIRE81M

hey ORANGEWHEELS01 just wondering do you have the real grupner jet sprint or the ebay nock off of it . i know you asked what motor i was useing but i have to diff motors for the two diff drives

dirtracer4

What are the jet sprint hulls made of and how much do you think it would cost to get it to the states? I did see where they give the name of a guy in the US to e-mail, but the link is no good. How much is 183,000 euro anyway?

That dual jet drive setup would be nice!

headhunter23

Conversion would would be 265 usd(plus banks margin), and seems to be min 50usd to ship, atleast that was based on 2 jet drives ordering through them. I'm sure shipping the hull would be more expensive.

Good quality, expensive though. You could get 6-7+ knock offs here for the same price. Love the knock off.

Ivan.

DRAGONFIRE81M

just a bare hull was almost $200 with out shipping im thanking about getting the blue foam out and shaping one for a mold and just glass over it . it said the hull was glass with a gull coat

dirtracer4

Can't beat the knock off jet sprint for $30 I'm sure it will work fine for what I'm wanting to do and if it doesn't hold up or get bashed, I have two more for back ups. Still waiting on the esc's before I can try it out.

brushlessone

hey there all ive also got a knock off jetsprint, ive ripped everything out and got the servo in place for steering and installed my 180s 20mm brushless 6800 kv motor from my 1/18 car with a 30 amp mystery esc of ebay , seems to pump alot of water fromt he test in the pool but the motor gets hot to touch after 20 - 30 seconds of pushing water ... so im guessing that i need a lower KV motor at 180 size? or a larger 280 size at lower KV??

DRAGONFIRE81M

ok first what voltage are you running . 6800kv is almost dobble what you can run on this drive come down in to no higher then 3200kv . i found a 20mm 2900kv on ebay for around $40 shipped that i plain on buy pretty soon for a nother nockoff there is a combo motor ,esc for $60 to . ill post and update with links when i get to work

opps i mint $30 for the motor heres the link http://cgi.ebay.com/RC-Hobby-2900-Rp...ushless-Motor-
H_W0QQitemZ280194267790QQihZ018QQcategoryZ34055QQt cZphotoQQcmdZViewItem

and heres the combo http://cgi.ebay.com/RC-Hobby-2900-Mo...QQcmdZViewItem

even with this motor its a safe beat to run a cooling system for the motor . its a cheap insearents

brushlessone

im very unsure that the 20mm inrunner motors have enough tourqe ?mine gets realy hot fast? or is it becuase the one im using is a 2030 short version and realy high KV?. im running 7.2 volts nimh at the moment but im getting lipo 7.4 and 11.1 soon. On ebay ive seen 30 amp Mystery esc and 3000kv motor combos for 35$ AUS deliverd they have 16mm front mounting holes and the 2.3mm shaft wich will fit straight up (link under post).. the only thing im unsure about is that its a outrunner not a inrunner i might try that one first but im also going to order a HXT 2445 (370L) 3790kv Brushless Inrunner for about 30$ deliverd from united hobbies.. the specs for this motor are under my post

HXT 2445 (370L) 3790kv
Motor Size: 2445 (370L)
Speed: 3790kv
ESC Required: 20A
Voltage Range: 6~12v
No Load Curr: 1.2A
Max Load: 35A
Diameter: 24.2mm
Front Mounting Hole Distance: 16mm
Front Mount Thread Size: M3
Shaft Diameter: 2mm
Shaft Length: 12mm
Weight: 95grams

CHEAP ESC MOTOR COMBO
http://cgi.ebay.com.au/3000kv-Helico...QQcmdZViewItem

DRAGONFIRE81M

just dont run 11.1 on that 3790kv and still put a cooling system in . only bad part about useing the outrunner is you cant cool it with water but you can make a fan for it . the reason you cant water cool is b/c the can turns with the shaft . im running a 2580kv 380-400 can size which is 28mm the motor doesnt get really hot on 11.1 but i like the insarents
oh ya mkm tryed a 3700kv and malted a mauba 25 . just a though im sorry i really did answer you ? from what i have seen with the others on here the 20mm over 3200kv is too small for this drive . now with that said if you where to put the grupner mini jet in then a higher kv would work fine . example im running a 3550kv in a 22" with a minijet on 11.1 . the reason is the nock off has a larger and more pitch on the impaller then the mini jet

brushlessone

ok i might try and get something around 2800 3200 kv in 28mm 380s range if it wil stay cool better but all i have seen so far are ones with 19mm mounting holes and 3.175 shafts .. the 24mm 370s ones are correct 16mm fit and 2mm shaft i think this motor below may be the one i am going to purchase wich is 2900kv, equivilent to 10 - 11 turns and at 45mm long it has plenty of space to watercool it the 35mm version is a higher rated KV and it would get hotter to produce the same power roughly going by feigaos brushless inrunner tech sheets wich u can get of their webpage

http://www.hobbycity.com/hobbycity/s...idProduct=4197

HXT 2445 (370L) 2900kv Brushless Inrunner
Motor Size: 2445 (370L)
Speed: 2900kv
ESC Required: 20A
Voltage Range: 6~12v
No Load Curr: .5A
Max Load: 34A
Diameter: 24.2mm
Front Mounting Hole Distance: 16mm
Front Mount Thread Size: M3
Shaft Diameter: 2mm
Shaft Length: 12mm
Weight: 95grams

DRAGONFIRE81M

cool man depending on shipping coast i thank you just canged my mind on that other motor and its the same kv thanks man

brushlessone

no worrys man ive got another jetsprint clone on its way too so im going to grab a few of them by the way how do you remove all the stock electronics from the boats ? do you heat up the hull with a hair dryer or heatgun to melt the glue? or just pry them off? , il post some pics of my boat sometime in the next few days when i get ma camera back

headhunter23

The components are hot glued in, with some prying with pliers you will get the components out. The drive itself is screwed in so ensure to fill holes when gluing back in place. When you cut the top, try to leave a margin of atleast 1cm, perhaps more on the ends if you intend on using the little locking polls for the top.

Hey dragon, you know how I was doing testing on the 3200 using both 11.1v and 7.4v, I think you can up the rpm just a smidgen to 3400-3500 per kv but that would be it on 7.4v, and would need certainly need cooling.

Also I was thinking, if Brushlessone cut his voltage in half to 3.7v, then he should beable to run his outrunner, I'm sure it would pull quite a bit o amps, plus either modding his batt or getting new 3.7v batt might not be the best way.... ahhh shoot, the esc's can't even operate that low right? Ah skip that idea. Woulda been cool if you could, would mean a further reduction in weight. Although the knock off seems to work better with a certain amount of weight.[:-]

Ivan.

Editpoint:
Brushlessone, first post is inside look of components etc as I was tearing them out.
http://www.rcuniverse.com/forum/m_65...11/key_/tm.htm

DRAGONFIRE81M

after removeing the drive i came in throw the botom hole with a long blade knigh and pryed and cut . the hot glue they used is some strong stuff . im not sure how the others did it

DRAGONFIRE81M

hey headhunter me need to get some gps's and see whats really going on with the kv rateing . also i cant remember how was the heat on the 3200 and the esc when you ran it on 11.1 . im thanking oh takeing the impellar from the nockoff cutting it down and putting it in the grupner . and do some breading .

retaobcr

Mine came in with the servo and speed control not glued in. Just cut like picture shows and you'll be fine. Motor, just get a 3200 on 7.4-1650 lipo and a 30 amp esc. I got a Common Sense charger and balancer in one container and works great. BTW, am retired and was suggested this unit, so i got it.

dirtracer4

First knock off I pulled apart the electronics came right out with just a little wiggle. The next one took a little more muscle and time wiggling loose. Just grab those big black boxes and work 'em loose. My first one has a Walkera 20mm 3200kv on 7.4v, but I'm also doing another using a helimax 28mm 2580kv on 11.1v (like dragonfire's).

DRAGONFIRE81M

i would rather run a higher voltage to keep the amps down . with the 2580kv on 11.1 that comes out to 28638rpm . if you ran the 3200 on 7.4 thats 23680 rpm with a lot more amp draw which = less run time . and your going a little slower

headhunter23

Pulling more amps merely means more heat through the esc, motor. I actually prefer higher voltage, because it means less heat for the same power. But then the packs are heavier too. Which is one reason for liking the lower voltage, not to mention cheaper. Seems to be more of a personal preference, for this boat I like being lighter, the 2 packs I stick in equal 4000mah anyways so I get plenty of run time regardless. I still have to see a video where someone overpowers the drive and causes cavitation as I was unable to with 11.1v at 3200rpm/v on 25amps.

Ivan.

dirtracer4

I will try 11.1v w/ the 3200kv, but just thought that 35,500rpm might be too much for this drive. I'm to new to understand the amps to volts relation.[sm=frown.gif]

DRAGONFIRE81M

well hell i guess ill take the motor out of the 22" and see if the drive will explode . nothing like hearing 39405 rpm come screming by you .
how is two 7.4 2000mah pack less then one 11.1 2400 mah

headhunter23

Power is really the total watts, which is simply volts times amps = watts. 746 equals 1 horse. For example riggers scream with tons of power, they run on what normally 7.4v but they are drawing 80amps and up depending on the setup. If you want to compare batt power it would be :

7.4X4(2X2000mah)=29.6watts per hour worth of energy.
11.1vX2.4=26.64 watts per hour worth of energy.

So if you were drawing the exact same wattage(this part would be complicated to get exact because it would be dependent on rpm, prop etc getting that combo just right) in both high voltage setup and the low voltage, you would have more run time with the 2 7.4's.

For me personally the increase in speed for going 11.1v on the 3200rpm was negligible but there is a slight speed difference. That's why I was suggesting if you ran the knock off on 7.4v I would think you could gain a little more speed by upping the rpm just a smidgen to max the drive, as that's what I seemed to have hit running on 11.1v.

And quicksilver is going to have to weigh in on this too but from all the research I've done on jet drives, there is a maximum amount of water that can go through the drive. No matter how much power or speed, it would not increase thrust after a given point. Which is why I was surprised about the cavitation, would have thought at max suction, no air would be getting in, unless it was sucking air directly from the drive shaft itself. Actually that would explain the cavitation.

Ivan.

DRAGONFIRE81M

there is two ways of looking at this you running two batterys at once to get a longer run time with out haven to brang it back in . in my case i like to run one battery at a time so when the one battery starts to drop off i brang it in check it over good tip to check for leaves and grass rapped around the shaft . then i pop the other battery in and off i go . the way i see it running four cells at one time is heaver the running 2 . your right its all about personal prefrace . the part on cavitation. you can force nthe water at so much force that you can couse air bobbles