danny boy Posted July 17, 2013 Share Posted July 17, 2013 Hey guys. Just got my NQD jet boat running. Decided to use a 2600kv 380L motor in the hope it wont need a cooling jacket and reserve the whole cooling power for the Hobbywing marine 35a ESC. Power is insane and pulls like a train. Very impressed so far. Pics to come later of the set-up. Later on I will swap out the motor for a Keda recommended Tamiyacowboy (thanks for the advice mate ) And possibly go for a higher ampage speedo. Thanks for reading Pics soon Quote Link to comment Share on other sites More sharing options...
Tamiyacowboy Posted July 17, 2013 Share Posted July 17, 2013 (edited) heya danny grats on the sprint boat build. flat waters they go balistic shallow streams and rapids they like to climb them to, can ride the bow waves and likes holding boat under throttle into the wave , remember always shut down the throttle if you get to shallow draft of water under boat, or she gets grounded. anything the pump indgests will blow the impeller ( prop ) out , also keep an eye on those motor temps make sure they dont get to hot, if not you can always watercool in other ways. Edited July 17, 2013 by Tamiyacowboy Quote Link to comment Share on other sites More sharing options...
danny boy Posted July 17, 2013 Author Share Posted July 17, 2013 heya danny grats on the sprint boat build. flat waters they go balistic shallow streams and rapids they like to climb them to, can ride the bow waves and likes holding boat under throttle into the wave , remember always shut down the throttle if you get to shallow draft of water under boat, or she gets grounded. anything the pump indgests will blow the impeller ( prop ) out , also keep an eye on those motor temps make sure they dont get to hot, if not you can always watercool in other ways. Thanks for the advice mate Just been mocking up electrics. Is this going to be too much weight at the back of the boat? Quote Link to comment Share on other sites More sharing options...
Tamiyacowboy Posted July 17, 2013 Share Posted July 17, 2013 done mine like this buddy kept the battery just infront of the motor, you tend to balance a boats COG around 25-35% its total length i shoved my esc on the left ( looking from behind boat) and kept my steering servo and my rx on the right side. you can just make out the rx channel pins on the right side stuck to side of a nano servo. i glued/siliconesealed a plywood plate into hull just fore of the motor and screwed in some velcro strapping to hold battery fully Quote Link to comment Share on other sites More sharing options...
danny boy Posted July 19, 2013 Author Share Posted July 19, 2013 How much water is too much water in the hull? Have been sealing the hull with silicone and epoxy for the last two days, Eveything should completely water tight, but is not. I dont get it. In a bath test the hull stays bone dry until approaching full throttle. After about 10-15 seconds at full throttle there is a small puddle about the size of a 5 pence piece in the back of the boat. Should I be going for 100 percent dry inside the hull? Thanks Quote Link to comment Share on other sites More sharing options...
Tamiyacowboy Posted July 19, 2013 Share Posted July 19, 2013 (edited) yeah want dry as dry can be. you may want to do an un-install. yep sounds nasty and its not like anyone wnats to rip out stuff they just put in. dont tell me, you cannot see where water is coming in either ? , same problem i had. what i done is took pump and motor out, then on the pump unit where the impeller sits. you see the stator plate ( what the back of boat butts upto) and the small stubb ring that pokes through the rear of the transom. well thats where your waters coming from. so before refitting grab a twig or something and a good dollop of silicone sealant. now run a bead all the way around the STATOR plate , i just painted the stuff on so i had a good thick pad of silicone all around the stator plate and upto the stubb ring, where the pump sits in the bottom of hull ( intake) give this a real good bead of silicone all the way around the inside of hull , now seat the drive in boat and poke the stubb ring through the transom hole. Any silcone that you see squeeze out give a little wipe away, now screw down the hull screws first, then screw on the rear boost nossle making sure the prop shaft fits into the little brass bushing. Take that twing and a good dollop of silicone again and go around the INSIDE where the stator, sits flush with the inside of the boat, shove that silicone all around the area, then leave alone DO NOT TOUCH. meanwhile, more silicone on that twig and spread it around the inside baseplate of the pump where it to joins the hull. JOB DONE. now leave it to cure atleast 24hrs, dont do nothing just let her sit and cure up fully. maybe even 48hrs. want to give enough time for all that silicone to set up. i even put silicone in the hull screw holes and seated screws down so everything go siliconed up lol. then bath test again, just a recheck and run to full power and down again. then open water test, run her 5 mins up and down the throttle range, have a check for water ingress. IF your lazy and want no re-install hassle the other way is to re-silicone the pump installed inside the hull. using the twig and silicone , gunk it all the way around the rear inside transom to pump stator, seal the rear as much as possible. i found this was the area that leaked under pump water pressure. Edited July 19, 2013 by Tamiyacowboy Quote Link to comment Share on other sites More sharing options...
danny boy Posted July 29, 2013 Author Share Posted July 29, 2013 Just given that a try Sorry it took a week to reply I forgot I was going away haha. Hopefully this works now, i'll find out in a couple days Quote Link to comment Share on other sites More sharing options...
Tamiyacowboy Posted July 29, 2013 Share Posted July 29, 2013 no worrys hope you way stay was an enjoyable one to. yeah it is just a case of good old silicone till it stops leaking lol, make sure you give it a good 12 hrs before setting the pump running, give the gunk time to cure and go off Quote Link to comment Share on other sites More sharing options...
danny boy Posted July 30, 2013 Author Share Posted July 30, 2013 I don't get this boat. I resealed over 36 hours ago so I know that the silicone has set. I've done everything you suggested, yet the boat still leaks. And to annoy me even more, its finding the pressure to squeeze water through set silicone, yet doesn't have the pressure to push water through the cooling lines, which surely should be an easier thing to do? Back to the drawing boards again I think. Quote Link to comment Share on other sites More sharing options...
danny boy Posted July 30, 2013 Author Share Posted July 30, 2013 Got the water cooling working! Mistake was on my part. I had the water inlet facing away from the stream of water instead of into into. So thats no longer a problem. Got to now what I can do about sealing again. Its no where near as bad as it was. just beads of water spotted around the place. Could even have got in there when i was taking the lid off. So a happier danny boy now its almost sorted Quote Link to comment Share on other sites More sharing options...
Tamiyacowboy Posted July 30, 2013 Share Posted July 30, 2013 can always leave a couple small bits of paper kitchen towel in the rear, soak up any ingress best way is, when next use her tape up, but when you untape and remove canopy/hood just wipe it over with a cloth, that way you will see if its bone dry or has a tiny leak. Quote Link to comment Share on other sites More sharing options...
danny boy Posted August 6, 2013 Author Share Posted August 6, 2013 Finally finished Thanks for the advice Tami. Great little boat. Any way to get it to stop bouncing though? Would be a lot faster if it stayed on the flat. Proabably just because I'm running through my own bow wave. But great fun Quote Link to comment Share on other sites More sharing options...
Tamiyacowboy Posted August 7, 2013 Share Posted August 7, 2013 looking great danny and also sounds awesome to. yes the skipping is her riding on her own bow-wave to keep the pump primed up a tiny shift in battery placement slightly forward, or some bluetack in the nose should help bring that porpoising to a very very minimum. what you do not hear is the pumps RPM shoot skywards as the pump looses its prime and sucks a skin full of air in. you will hear this as a zingy type of noise as the pump ingests air and not water, over time you will find yourself looking for glass water, when its dead still and mirror/millpool flat. then you will find your opening that throttle to full max. just remember you have NO reverse ( so plan cornering ahead) and turning must be done under power ( without pump running, your steering does not work) Quote Link to comment Share on other sites More sharing options...
aidensere07 Posted August 12, 2013 Share Posted August 12, 2013 If you still have a leak, it will be coming from where the shaft goes through the rubber grommit on the jetdrive itself, fine at low speeds but when pushing it , it does leak, i tried to find a bearing for it but couldnt get one, i ended up taking the bushing out of the stock motor, grease, add the bushing and then add the rubber one back in, this helped a lot Quote Link to comment Share on other sites More sharing options...
Tamiyacowboy Posted August 12, 2013 Share Posted August 12, 2013 (edited) If you still have a leak, it will be coming from where the shaft goes through the rubber grommit on the jetdrive itself, fine at low speeds but when pushing it , it does leak, i tried to find a bearing for it but couldnt get one, i ended up taking the bushing out of the stock motor, grease, add the bushing and then add the rubber one back in, this helped a lot gah lol, means i now have to de-seal the whole unit lol. frolocks to that lol. i seen a couple bearings, one that could fit into the rear stator housing, its a needle type bearing. second was from those mini/micro helis, most of them run a bearing in the top frame section. also mini quads /brushless motors have 3mm shafts its just the bearing depth and width we have to contend with. and the amount of removable plastic we have to fit them. we need a very cheap CNC alloy mini berkley pump lol so we can ramp the kv to like 125,000rpm and dump like 1kg thrust from holeshot lol a 8000kv on 11.1v will throw us 88.800 Rpm, ( just imagine 8s cell pack ) Edited August 12, 2013 by Tamiyacowboy Quote Link to comment Share on other sites More sharing options...
aidensere07 Posted August 13, 2013 Share Posted August 13, 2013 there is one way you could sort it, drill 2 holes in the transom so you can get at the motor screws to remove the motor, undo the shaft adapter and work from there? or just keep emptying it every so often? Aiden Quote Link to comment Share on other sites More sharing options...
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