HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Feb 10, 2012, 08:49 PM
Registered User
Joined Jan 2012
13 Posts
Discussion
open-heart surgery on a NQD Lobster

Hi folks,

Bought a HobbyWing 2848 SL 3900kv, Seaking-60A, and 3S Lipo to put in my arrow wind lobster 757T-4017 but realized there are no holes for the intake of water for the cooling jacket. Few questions about doing the swap:

I assume I'm going to have to take the whole top of the boat off to do all this work, since I need to get the new ESC in there as well. Just use an exacto knife to cut around the seal that's on there now?

What kind of tubes are best for this and where would I get them?

What's the best place? On the side or out the back next to the rudder?

Just drill a hole and stick the tube out? Make if flush with the side of the boat, or sticking out a bit?

What do you reseal the boat with once you put it back together?

Any other advice?
stronzo420 is offline Find More Posts by stronzo420
Reply With Quote
Sign up now
to remove ads between posts
Old Feb 10, 2012, 09:59 PM
I feel the need for speed!
scorpion1's Avatar
Southern U.S.
Joined Jun 2008
7,086 Posts
I'd be concerned about turning 50,000 rpms with that 3s batt...................
scorpion1 is offline Find More Posts by scorpion1
Reply With Quote
Old Feb 10, 2012, 11:06 PM
Registered User
Gordonsville,Virginia
Joined Nov 2009
335 Posts
I would feel a lot better with a 2s lipo , I think you'll be cooking things with a 3s lipo . As far as resealing try some hocky tape . If you can't find it at some sporting goods store try www.offshoreelectrics.com they have it . Looks like it would work well with that boat . Good luck !!
highflyerbill is offline Find More Posts by highflyerbill
Reply With Quote
Old Feb 11, 2012, 01:11 PM
Registered User
Joined Jan 2012
13 Posts
hmmm. may return the motor then. what size motor would you recommend for a 3s battery? how can I tell which battery should go with which motor specs?
stronzo420 is offline Find More Posts by stronzo420
Reply With Quote
Old Feb 11, 2012, 06:48 PM
I feel the need for speed!
scorpion1's Avatar
Southern U.S.
Joined Jun 2008
7,086 Posts
Quote:
Originally Posted by stronzo420 View Post
hmmm. may return the motor then. what size motor would you recommend for a 3s battery? how can I tell which battery should go with which motor specs?
Something in the 2500-2900kv range.

This powerful little 4 poler outta do it! http://www.hobbyking.com/hobbyking/s..._Inrunner.html
scorpion1 is offline Find More Posts by scorpion1
Reply With Quote
Old Feb 11, 2012, 10:31 PM
Platinum Card Member
sundogz's Avatar
Joined Sep 2007
326 Posts
I've done one of these conversions, and that 3900kv HK will be fine. Start out with a 32mm prop and work up. Don't split the hull to install parts, you won't get them back out! There is precious little room in that hull, so I moved the sponson booms forward 2" to make more room for the lipo. Remove the pinstripe tape that covers the top/bottom hull seam and seal it with superglue. Use superglue at every seam - sponsons, booms, etc. to waterproof. The hardware from any mini hydro (small bolt, tenshock) that uses a 75mm rudder will fit. Use the provided thumbscrews and hockey tape to install the hatch. These area blast to run.
sundogz is offline Find More Posts by sundogz
Reply With Quote
Old Feb 11, 2012, 10:42 PM
I feel the need for speed!
scorpion1's Avatar
Southern U.S.
Joined Jun 2008
7,086 Posts
The 3900kv is fine on 3s?
scorpion1 is offline Find More Posts by scorpion1
Reply With Quote
Old Feb 11, 2012, 11:42 PM
Platinum Card Member
sundogz's Avatar
Joined Sep 2007
326 Posts
Quote:
Originally Posted by scorpion1 View Post
The 3900kv is fine on 3s?
In this situation it should be fine. I am using a 3600kv 28mm in mine and it could handle more (riggers being very light on the water). If it's the 28mm HK that comes with a water jacket, it can take it - they are tough motors. I have one of these motors in an ABC jet ski and another in a tenshock microhydro! Unladen it's borderline crazy, but in use it is just plain fast. He's using a Seaing 60A (with a burst rating of 120A), or I would have recommended a bigger esc. Use a decent 30-40C (&up) 2200-2500mah lipo as this arrangement could puff lesser lipos.
sundogz is offline Find More Posts by sundogz
Reply With Quote
Old Feb 12, 2012, 02:13 AM
Registered User
Australia, VIC, Blackburn North
Joined Feb 2011
825 Posts
I wouldn't use superglue to stick things together.

Use Shoogoo. It sticks to this stuff better than brittle superglue & seals properly.
mozzyrocks is offline Find More Posts by mozzyrocks
Reply With Quote
Old Feb 12, 2012, 09:14 AM
Platinum Card Member
sundogz's Avatar
Joined Sep 2007
326 Posts
Quote:
Originally Posted by mozzyrocks View Post
I wouldn't use superglue to stick things together.

Use Shoogoo. It sticks to this stuff better than brittle superglue & seals properly.
Superglue flows easily into the seams and seals them. And it is as flexible as the hull is IMHO. I did this on mine and it worked quite well.
sundogz is offline Find More Posts by sundogz
Reply With Quote
Old Feb 12, 2012, 09:24 AM
Registered User
Australia, VIC, Blackburn North
Joined Feb 2011
825 Posts
I used shoogoo on my NQD Tear Into jet boat with excellent results.

Each to their own, I just find superglue too brittle for flexible applications.
mozzyrocks is offline Find More Posts by mozzyrocks
Reply With Quote
Old Feb 12, 2012, 10:00 AM
Platinum Card Member
sundogz's Avatar
Joined Sep 2007
326 Posts
Quote:
Originally Posted by mozzyrocks View Post
I used shoogoo on my NQD Tear Into jet boat with excellent results.

Each to their own, I just find superglue too brittle for flexible applications.
Yes, I agree shoogoo would work well on a flexible hull such as the Tear Into. Though it's also made by NQD, the Arrow Wind is rigid (thick) plastic, and the top and bottom is screwed together with a thin foam gasket between them. Superglue makes the whole hull more rigid. I sealed the screw holes in the bottom of the hull with melted wax, shaving them off flush with a knife afterwards.
sundogz is offline Find More Posts by sundogz
Last edited by sundogz; Feb 12, 2012 at 10:06 AM.
Reply With Quote
Old Apr 23, 2012, 11:26 PM
Registered User
Joined Jan 2012
13 Posts
getting back to this now that the weather is getting nicer. hey sundogz, was looking at the pics you sent, and some of the parts obviously won't fit into the original mounting holes. What did you do to fasten the parts in there?
stronzo420 is offline Find More Posts by stronzo420
Reply With Quote
Old Apr 23, 2012, 11:27 PM
Registered User
Joined Jan 2012
13 Posts
and what kind of rudder did you use on yours?
stronzo420 is offline Find More Posts by stronzo420
Reply With Quote
Old Apr 24, 2012, 07:30 AM
Platinum Card Member
sundogz's Avatar
Joined Sep 2007
326 Posts
I used the original motor mount and hot-glued the servo into the hull. The 75mm rudder is made for a mini hydro. 50mm strut with 4mm flex/prop shaft. If you use the straight shaft it will hop at speed; so use a flex. You'll need to bend the stuffing tube to get a neutral angle at the strut. Heat the tube red hot/let it cool and it's easier to bend.
sundogz is offline Find More Posts by sundogz
Last edited by sundogz; Apr 24, 2012 at 08:04 AM.
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Help! Open heart surgery on a cheap TX bennz Radios 3 Feb 13, 2011 07:24 PM
Open Heart Surgery, Hitec 555/Electron6 quantumMechanic DIY Electronics 6 Jun 17, 2005 03:21 PM