jetsprintbasher976

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Got it today cant wait to build heres a quick mock up she's pretty

headhunter23

That plastic or glass? How much was the kit? Looks identical to the knock off.

sundogz

Headhunter, this looks identical because the Tear Into is a knockoff of this boat - (Graupner Jet Sprint). NQD makes a knockoff of Graupners outrigger too (Silver Bullet), and calls it the Arrow Wind.

headhunter23

ok, but is that glass? It looks like abs, for some reason I thought it was someone else that made the original.

sundogz

Plastic. Here is a link. [link=http://www.modelflight.com.au/rc_model_boats/boats_rc_models_graupner_jetboat_jetsprint.htm]Jet Sprint[/link]

Curiously, the picture of the bottom of the hull shows a small delta, while the picture of the completed version below shows a much larger area.

headhunter23

That must be whats throwing me... i thought the original was slightly larger than knock offs and the kit was made with fiberglass.

jetsprintbasher976

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Got some work done today got the jet in and sealed it mounted roll cage with a little somethin extra [tryin to look diffrent] picked up paint today fl lime . goin to put little distributer and wires on engine for scale look also got wing munted , and so far i haven't seen boble heads so idid them there sweet.Also got my first jet boat runnin to day for first time longer than 1 min.and she is pretty fast for a cracker box will have vid soon, and ripped the grate off that ook 20min to build woops, so i just glued some mesh on and will test it tommorow. these outrunners for the helis are awsome there light fast and have plenty of torque and i had 20 fin mins of run time it was crazy i had two batterys and only got threw one till i couldn;t see anymore. will have lot more pics and progress tommorow

jetsprintbasher976

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jetsprint got some paint lime looks very nice! crackerbox got over night makeover , and got some leds and went crazy today but its sweet. new paint job to. can't wait till it stops raining but if it rains a lot i gonna play in the driveway and gutter

jetsprintbasher976

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major progress to day the hull was so scetchy i almost f it up got the steering in last night alot of painting this morning made the moter mount out of plexie. the outrunners dont need cooling they turn so much air inside the hull thats a big +. waiting on the lipos to balance it out and run parallel but for the mean time i used a big lipo that barely fit, and it put it way off balnce. couldn't test in tube i couldn't hold it in the water with one hand!






when i tested it was fast so much more handling than the crackerbox, will have video tommorow weather permit? and more pics

graupner jetsprint kit /origanal $125
4000kv mystery brushless outrunner with 30amp esc $25
25c 1500mah 11.1v 3cells lipo x2parallel $30
traxxas brushless waterproof 2075 servo $25
jrx2i radio $45
graupner mini jet unit
$250 all put together

jetsprintbasher976

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anyone know good substitution for the graupner 3.2mm to 3mm u joint

785boats

That's one hell of a job you're doing there. Looks great.
Can't help with the coupling unfortunately.
I do hope that you are going to drive it like this.

[link]http://www.v8superboats.com.au/index.php?action=video[/link]

Cheers.
Paul.

jetsprintbasher976

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http://www.youtube.com/watch?v=EH3ot5E4Q2g
heres my first vid pretty crappy but it only my phone just got new lipos and parallel harness to day will have up date. new servo position. also while testing hit rock and rolled on land for first time but the rock got it pretty good pic off new wires on engine and possible air intake . thegrate too a beating but will redo for tommorow . the new moter mount that i made for better support [broke 2 u joints from shaking] in 2 days only broke the 3mm side so i put the 2 x3.2mm together and thats what im runin now hope it holds up. these batterys are so sweet 100g a peice 11.1 1500mah 25c X2 parralle 15m run time is sweet 20 if i take it easy. the boat is so light with these new lipos good investment i'm lookin at same kind but 1800mah. i will show u how i can drive on vid forgot phone when i was at sandbar today. she looks pretty and she can put down some hot laps

headhunter23

Going down a size, sometimes ur lucky if a bit of heat shrink if the size difference is so little, ensure that set screw is locking in a groove and loctite. Other way is to go to hobby store and find brass or aluminum tubing that slips over ur current shaft. Aluminum tubing can be cut easily via flat blade and rolling blade accross top of tubing on table, brass... tube cutter i guess.

Ivan.

damfurst

Your sprint boat looks good. I like the roll bars alot. I also tore up the u-joint that came with the mini jet drive unit. I switched to a metal ujoint for the shockwave 26 or the apache 24. The only problem was you had to ream one side out to 1/8" because both sides are 3mm. But the best replacement I found was making one from the larger graupner ujoints . I think you can get the 4mm X 3.2mm one. It is larger than the 3.2 X 3mm one so you have to make a motor mount and move the motor a little forward. I run mine with 3500kv heli outrunner and it works great. Vibration went to null. I think hobby lobby has them. It comes with a middle part (don't use it) and an brass insert for the 4mm side to make it fit 3mm. The other option is to use a flex coupling also made by graupner. They also work well but move the motor much farther forward. You would also have to make brass insert adapter out or 1/8" brass tubing. Or do what headhunter said. That would help straighten the shaft alignment for sure. below are pics of both examples I gave you.

jetsprintbasher976

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i sold that same flex wih my old seaking 3600kv engine it was to big, also i have a graupner 4mm u joint. and r u having cooling issues with that engine. my outrunner cools its self but if u didn't notic i have the front mount outrunner. .all i have to cool is the esc. i have some engines on the way first is for my brothers cracker box second is for my crackerbox and there is anothere 1700kv on the way for a airboat i like these engines if u didn't notice there cheap lights tourqeie and fast

<colgroup><col width="93"></col></colgroup><colgroup><col width="208"></col><col width="167"></col></colgroup>

D2830-3850	Helicopter / Airplane
Specification
Battery :		NiCd / Nimh / LiPo Battery
RPM/V :		3850kv
Max. efficiency current :		97%
Input Voltage		6-22V
Max Current		26A
Continuous Current		20A
No load Current		0.7A
Internal Resistance		51mΩ
Motor Dimensions (Diameter , Lenght) Shaft Dimensions (Diameter , Lenght)		26mm , 27.4mm 3mm , 14.8mm Feature : [*] Effectively the flight performanc[*]Low Price and High Quality[/list] Motor Specification : Speed Constant: 3200KV Motor diameter: 27mm Shaft diameter: 3.0mm Motor length: 30mm Motor weight: 48Grams Free load current: 17A Max efficiency: 85% Max current :17A [/list]

damfurst

I did burn up one of those motors because I had no cooling on it at all. These Emp motors that I'm running have mounting holes on the back of them so I've made up some alum plate w/tubing welded to it for the cooling on them. It has worked the best (much better than coils). On the outrunners like yours you can do the same thing by putting a cooling plate on the front before it mounts to the drive. It will draw the heat away from the motor toward it and keep the temp down. I'm trying a 4700kv outrunner on my cracker box that I installed an Abc Hobby 22mm jet drive in. It will have the cooling plate on it like I've described. Should have that done and pics & vid done by end of the week. I'll post on the jet drive thread. They also make a cooling mount for outrunner[link]http://www.offshoreelectrics.com/proddetail.php?prod=ose-509b14[/link]s. OSE has them. Here's a pic.

jetsprintbasher976

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new grate put on last night tested fine today lowered top speed but id rather have protection on the impeller than to speed.i hope u like the vid best my phone will do but u get the idea of the hole shot in the beginning then cornering and speed and doughnutzz!!!! by the way this is the sandbar i rolled over lol just like in the the jetsprint races http://www.youtube.com/watch?v=4qUHPY5BTR8

headhunter23

Hey jet sprint basher, I've done my inlets like yours on every boat, but a bunch o the guys have ... some sort of fine grill mesh on their inlets, surprisingly this has kept speeds up or close to it, plus they reprime instantly. Don't ask me why, I would have figured the opposite.

Ivan.

jetsprintbasher976

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i didn't see anyone else's boat but i have a fine aluminum mesh on my cracker box because i spent 20 min soldering one with the brass rod with 9 strips i think and it got ripped off and lost i might try on my sprint because of the re priming theory

sundogz

Here's an example of what Headhunter is talking about. This is a mod I did the other day to the intake of an ABC Jet Ski I plan to race soon. On the smaller jets (this one included) I prefer 1/8" (3mm) wire mesh. This is about double the opening size of window screen - which is too restrictive. The mesh is atttached with hot glue all around the edges. The screws holding the jet in place also hold the mesh while the hotglue is applied. As you can see this makes for a clean, almost flush solution to impeller protection.

jetsprintbasher976

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jetsprints all over ebay finally can't wait to get one so i'm not bashing $125 original hull and then i'll beat the piss out of the knock off on stuff i wouldn't try with the real one and the iceing on the cake is there in pittsburg only like 40 miles away sweet

jetsprintbasher976

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second coat of paint and decals and final sanding oon hull will have rollbar painted soon new battery position

headhunter23

Jet sprint, nice job... but... aren't ya supposed to bash this boat on rocks and stuff?! That's the most fun o these little beasts, trying to get up up and through everything!

jetsprintbasher976

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if u didn't notice the boat kit was $125 knockoffs are about $50 and preassembled. i bought this cheap but it was still pricey and i took my time to design and build with way to much research manly on this fourm and i want it to last and look nice to so im buying a knock off to beat the **** out of not my mean green machine http://www.youtube.com/watch?v=4qUHPY5BTR8


graupner jetsprint kit /origanal $125
4000kv mystery brushless outrunner with 30amp esc $25
25c 1500mah 11.1v 3cells lipo x2parallel $30
traxxas brushless waterproof 2075 servo $25
jrx2i radio $45
graupner mini jet unit
$250 all put together

and plus were r pics of ur grate?

headhunter23

It's only money.

Geez grates.... ummmm... look at pics in "unofficial jet drive thread" ummm... starting somewhere around 130 I think.