Go Back  RCU Forums > RC Boats > Speed - Electric
Reload this Page >

The Unofficial all things Jet drive thread

Notices
Speed - Electric For all your electric boating needs.

The Unofficial all things Jet drive thread

Old 02-19-2009, 03:33 PM
  #2551  
DRAGONFIRE81M
 
Join Date: Jan 2007
Location: PORTLAND, TN
Posts: 1,760
Likes: 0
Received 0 Likes on 0 Posts
Default RE: The Unofficial all things Jet drive thread

i used a plane bulkhead fuel nipple. brang it on if your ever in tennessee [8D]
Old 02-19-2009, 04:14 PM
  #2552  
Vinnystoolbox
Member
 
Join Date: Jun 2008
Location: Bedford, UNITED KINGDOM
Posts: 98
Likes: 0
Received 0 Likes on 0 Posts
Default RE: The Unofficial all things Jet drive thread

I was only joking about the race but you never know.
Really i'm just hoping i didn't over do the motor it is a bit of a monster from all accounts, still i thought i was better to have too much power than not enough [&:]

I think my pickup will work, i just get less flow than expected a trickle at the speed i've tested rather than the spray i thought i might get, but that could be a good thing anyway seems to cool the pipe work pretty well. Bit concerned about having to move it as i've already used bits from 2 [:@] jetdrive kits to finish this boat, grrrrr at graupners quality.
Old 02-19-2009, 04:28 PM
  #2553  
MKMotorsport
Senior Member
 
Join Date: Oct 2005
Location: Monument, CO
Posts: 297
Likes: 0
Received 0 Likes on 0 Posts
Default RE: The Unofficial all things Jet drive thread

Dragonfire,

Is that a B36-56 Turnigy i spy in there?


MKM
Old 02-19-2009, 04:34 PM
  #2554  
DRAGONFIRE81M
 
Join Date: Jan 2007
Location: PORTLAND, TN
Posts: 1,760
Likes: 0
Received 0 Likes on 0 Posts
Default RE: The Unofficial all things Jet drive thread

yes it is . mkm is a 36-56-2600 and a simple 100a with a auqacraft water plate
Old 02-19-2009, 04:56 PM
  #2555  
DRAGONFIRE81M
 
Join Date: Jan 2007
Location: PORTLAND, TN
Posts: 1,760
Likes: 0
Received 0 Likes on 0 Posts
Default RE: The Unofficial all things Jet drive thread

well after going throw my high amp lipos i have found i need some higer amp packs i had a 4s 3000mah and a 2s 2000 mah pak bit the dust they both swalled . any ideas i thank im in the 45-60 amp range going by the temps of the motor and esc .
Old 02-19-2009, 06:46 PM
  #2556  
DRAGONFIRE81M
 
Join Date: Jan 2007
Location: PORTLAND, TN
Posts: 1,760
Likes: 0
Received 0 Likes on 0 Posts
Default RE: The Unofficial all things Jet drive thread

vinny what is the weghtof your boat without the batterys?
Old 02-19-2009, 07:09 PM
  #2557  
Vinnystoolbox
Member
 
Join Date: Jun 2008
Location: Bedford, UNITED KINGDOM
Posts: 98
Likes: 0
Received 0 Likes on 0 Posts
Default RE: The Unofficial all things Jet drive thread

Dragonfire the boat with lid and an esc but not batteries weighs in at 3lb9.25oz or 1.625kg if you prefer

Not had any joy looking for impellers, but found some fun other forums e.g. rocket boats

Anyone know where i can find out about DIY esc's??
Old 02-19-2009, 07:32 PM
  #2558  
DRAGONFIRE81M
 
Join Date: Jan 2007
Location: PORTLAND, TN
Posts: 1,760
Likes: 0
Received 0 Likes on 0 Posts
Default RE: The Unofficial all things Jet drive thread

not to bad on the weght . mine comes in at 2lb 8oz
Old 02-19-2009, 07:40 PM
  #2559  
Vinnystoolbox
Member
 
Join Date: Jun 2008
Location: Bedford, UNITED KINGDOM
Posts: 98
Likes: 0
Received 0 Likes on 0 Posts
Default RE: The Unofficial all things Jet drive thread

Wow amazing what a bit of aluminium tube and a stupidly big motor does huh, oh well it seems like a good weight when i'm holding it. I suppose there is a fair bit of epoxy and glass fibre in there too.

Wasn't trying to save weight if i'm honest didn't really think about it till you asked.

I guess it's because i'm not really planning to use it on rapids, or trying to go fast, just wanted something a bit different (DOH!) that was reasonable quick.
Old 02-19-2009, 08:06 PM
  #2560  
DRAGONFIRE81M
 
Join Date: Jan 2007
Location: PORTLAND, TN
Posts: 1,760
Likes: 0
Received 0 Likes on 0 Posts
Default RE: The Unofficial all things Jet drive thread

the reson i ask is your useing nicd battery or bricks as i call them . for go resolts in speed and runtime you wont it as light as you can get it . but i thank your pretty good i try to keep my boats around 5lb with this drive . but even if your a little over you have the larger motor to make up for it . see i wont this boat to be equaly fast as big blue was on 4s . but since this hull is shorter and the 3 blade impeller i have i thank i mite blow the deck off of blue
Old 02-19-2009, 08:23 PM
  #2561  
Vinnystoolbox
Member
 
Join Date: Jun 2008
Location: Bedford, UNITED KINGDOM
Posts: 98
Likes: 0
Received 0 Likes on 0 Posts
Default RE: The Unofficial all things Jet drive thread

Was going to go for lipo but read up about cells burning, exploding etc. and got too scared what with 2 small children in the house, so went for the slightly safer option.

As i say not looking for super fast, i would have saved loads of money and effort and just junked the electrics and replaced with brushless setup.

I was happy enough with it as it was RTR with the 540 motor it had, jet drive was just fun a project and something different, at least theres only 3 of these in the world now LOL.

It's 5lb 7oz or 2.48kg with the batteries, oh well not quite light enough [X(]
Old 02-19-2009, 08:33 PM
  #2562  
DRAGONFIRE81M
 
Join Date: Jan 2007
Location: PORTLAND, TN
Posts: 1,760
Likes: 0
Received 0 Likes on 0 Posts
Default RE: The Unofficial all things Jet drive thread

thats not bad like i said you have the ex torq to move it . you mite be supreised at what speed youll get . im thanking of tring her out on two nicd pack since i need some higher amp lipos then what i have .
Old 02-19-2009, 09:41 PM
  #2563  
grael
Senior Member
 
Join Date: Jul 2008
Location: Wellington, NEW ZEALAND
Posts: 589
Likes: 0
Received 0 Likes on 0 Posts
Default RE: The Unofficial all things Jet drive thread

vinnyst,
I've looked up DIY brushless speed controllers before, but I would rate them as an advanced electronics construction project at the moment. You have to have a microcontroller to sequence the pulses to the coil drivers, and it has to constantly monitor the feedback voltages, even at very high RPM. There is some free object code out there, but you need to be able to download the program code into the microcontroller too.

All quite a big ask, unless you are already pretty good at electronics. I had my own electronics and SW company for 4 years, and I've considered one, but it's cheaper to buy them out of China, than it is to buy the components individually, to make the circuitboard, etc etc.

For RC, you want high density SMD construction, and that's another challenge for a beginner, to solder small fine pitch packages without developing solder bridges where they oughtn't be !

I do have one brushess project in mind, but it's more likely to be around the end of this year, and it wouldn't be free source or design.
Old 02-19-2009, 10:19 PM
  #2564  
sundogz
 
sundogz's Avatar
 
Join Date: Nov 2008
Location: Ozarks, USA
Posts: 1,411
Likes: 0
Received 0 Likes on 0 Posts
Default RE: The Unofficial all things Jet drive thread

Yep, both of those boats are looking good. Vinnie: don't worry about low flow on your cooling system. If it's flowing, it's cooling. It doesn't take much. My knockoff just produces a trickle at speed, but the motor never gets more than warm. That location (for the pickup) should be fine.
Old 02-19-2009, 10:37 PM
  #2565  
sundogz
 
sundogz's Avatar
 
Join Date: Nov 2008
Location: Ozarks, USA
Posts: 1,411
Likes: 0
Received 0 Likes on 0 Posts
Default RE: The Unofficial all things Jet drive thread

And if you don't want the worry of Lipos (much recommended) you might try NiMh instead of Nicads - they hold more power per weight and can be charged with the same charger. I use them on my RC 4 wheeler for longer runtimes.
Old 02-20-2009, 07:10 AM
  #2566  
headhunter23
Senior Member
 
Join Date: Aug 2007
Location: Waterloo, ON, CANADA
Posts: 1,173
Likes: 0
Received 0 Likes on 0 Posts
Default RE: The Unofficial all things Jet drive thread

Actually I wouldn't worry so much about lipo's. The only time they seem to explode now would be if you over discharge them and try to charge them after. The water being able to get into the packs seem to be corrected at manufacturing. I think I have 20-30lipo's, only time ever with the fire is trying to save money and charger her up after discharging pack to near zero. Now I would just throw it in the garbage. It is the best technology for dollar and weight and amp draw. But you do need to ensure the lipo can handle the draw, which means u need to know the draw, also motor can suck more energy(nimh/nicd generally can't fully supply motor) and run at full potential.

Ivan.
Old 02-20-2009, 07:23 AM
  #2567  
DRAGONFIRE81M
 
Join Date: Jan 2007
Location: PORTLAND, TN
Posts: 1,760
Likes: 0
Received 0 Likes on 0 Posts
Default RE: The Unofficial all things Jet drive thread

im staying with lipos i just wont to get this boat in the water . thats why im going to throw my nicad at her . it did ok on my 3s max amp packs there rated for 25c
Old 02-20-2009, 11:40 AM
  #2568  
damfurst
 
Join Date: Aug 2007
Location: Lewistown, MT
Posts: 437
Likes: 0
Received 0 Likes on 0 Posts
Default RE: The Unofficial all things Jet drive thread

Hey Dragon & Vinny your boats are looking good!! I burned out my motor in my Jet ski, so am currently replacing with Emp 3200kv motor like in the Brick. We'll see how that turns out.

I have wondered too if Lipo's are or arn't waterproof? You guys know more about that than I.
Attached Thumbnails Click image for larger version

Name:	Us52827.jpg
Views:	47
Size:	164.6 KB
ID:	1140377  
Old 02-20-2009, 11:52 AM
  #2569  
headhunter23
Senior Member
 
Join Date: Aug 2007
Location: Waterloo, ON, CANADA
Posts: 1,173
Likes: 0
Received 0 Likes on 0 Posts
Default RE: The Unofficial all things Jet drive thread

All mine are.
Old 02-20-2009, 12:23 PM
  #2570  
Vinnystoolbox
Member
 
Join Date: Jun 2008
Location: Bedford, UNITED KINGDOM
Posts: 98
Likes: 0
Received 0 Likes on 0 Posts
Default RE: The Unofficial all things Jet drive thread

Cheers for the various info guys.

Thought the esc was a bit of challenge just a bit concerned with the one i had/am getting back as it has several boards and not sure how to make sure all components are suitably cool.

Water should be fine as you say any flow should do in fact too fast a flow would be detrimental to optimal cooling, my submersible/rescue (if your lucky) boat only produces a trickle and is fine.

The batteries i have are nimh anyway so no probs, i'm happy with them and maybe when i have funds again i'll invest in lipo, i was originally going to go lipo and had a different motor i would have used that was a xl version of the current motor with a lower Kv rating, so saved some weight there anyway.
Old 02-20-2009, 04:01 PM
  #2571  
headhunter23
Senior Member
 
Join Date: Aug 2007
Location: Waterloo, ON, CANADA
Posts: 1,173
Likes: 0
Received 0 Likes on 0 Posts
Default RE: The Unofficial all things Jet drive thread

Vinny the part u need to cool on esc is the aluminum on the fets. Cool the aluminum. Don't worry bout rest of stuff, although 7 boards sounds weird. It has reverse or something?

Ivan.
Old 02-20-2009, 07:11 PM
  #2572  
Vinnystoolbox
Member
 
Join Date: Jun 2008
Location: Bedford, UNITED KINGDOM
Posts: 98
Likes: 0
Received 0 Likes on 0 Posts
Default RE: The Unofficial all things Jet drive thread

No not seven, several. Think it was four don't have in my hand at the minute.

The reason i'm concerned is the my Dynam esc i modified to have a finned heatsink, had a warped board from new which meant only 2 fets where touching the alu. just worried this could be the same which might have what caused it to fail.

It's a Hextronic hxt120A in case anyone has any experience of them.
Old 02-20-2009, 08:25 PM
  #2573  
headhunter23
Senior Member
 
Join Date: Aug 2007
Location: Waterloo, ON, CANADA
Posts: 1,173
Likes: 0
Received 0 Likes on 0 Posts
Default RE: The Unofficial all things Jet drive thread

Get cpu paste, that's what is generally under the aluminum to transfer heat from fet to metal. Another thing you can try is goop around the edges and press hard on aluminum as it sets(sit book on it), this will prevent fets burning up with contact to water as that's generally how you burn out an esc also the heat like ya said. Or get some heat shrink that goes over whole thing.
Old 02-20-2009, 08:42 PM
  #2574  
Vinnystoolbox
Member
 
Join Date: Jun 2008
Location: Bedford, UNITED KINGDOM
Posts: 98
Likes: 0
Received 0 Likes on 0 Posts
Default RE: The Unofficial all things Jet drive thread

I'll post a pic when i get the replacement you'll see what i mean it's pretty odd i haven't seem multi board esc's before.

Suppose i could force thermal compound through gaps to fill all the voids between boards. Don't really want to mess with it incase this one dies too.
Old 02-20-2009, 10:23 PM
  #2575  
g master
Senior Member
 
Join Date: Oct 2007
Location: , NE
Posts: 147
Likes: 0
Received 0 Likes on 0 Posts
Default RE: The Unofficial all things Jet drive thread

hey could I use two mini graupner jet drives insted of one like big22bird,would it be easyer to do two mini ones then one
thanks

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.