similar

Another 'stock' video...

10x8

I love how you assaulted the rapid head constantly. Is that stock with Capt kirk controller, as in out of box ebay?

Peter

similar

Yup. All straight out of the box. I tried a 1500 mAh NiMH earlier(a week ago), but it let 'some' of the smoke out, so I changed back to the standard bat.

10x8

similar,
I love the rapids and the sound of your vid. Unfortunately, I built mine for utter abuse & jumps. I will test this on the morro.

Keep up the good work.

Peter

aum-offshore

lapistola28

Hey fellas .... I just built a yellow Tear Into after reading your forum . The problem is , i think the motor i have in it is too high a Kv rating . The one i have i got from Hobby King and its a 4800Kv after 2 or 3 minutes of running the poor battery is hot and the motor is a bit hot too . The battery is a 2200 Mah 20-30C 3S Turnigy Lipo .The ESC that i am using is a Turnigy 35Amp water cooled unit . My cooling comes straight off of the Stator through the motor then the ESC and out i. I have a huge amount of water cooling as the outlet shoots water about 8 inches off the side of the boat . Is the Kv just too high on this motor ?

DRAGONFIRE81M

the kv is to high for 3s lipo. you need to be in the 3000kv area on 3s and 3200-4900kv on 2s.

llDemonll

amusdh how are you getting such a high "tail" of water from your boat?? i love it!

DRAGONFIRE81M

use a smaller nozzle port for the outlet and it will pressurize and shot pretty far i have gotten about 16" spray doing that plus if you hold the cooling back a little it helps in heat transfer

pmdevlin

regarding the kv thing, I stupidly thought I knew better, and ordered a cheapo 3600kv, fitted it, and its been a real disappointment[&o]
Ran it on 1500 15c 3 cell, and it puffed the batttery after only 6 mins, ran it on a 2800 30c 3 cell (ignoring added weight) ran a bit longer, 10 mins, but the speed wasnt exactly great, then with a borrowed 2600kv same batteries, it ran longer, and certanly not slower, so am now waiting for the motor Demon and othesr use, the walkera 3200kv.

I was thinking that it was just another cheapo, but forgot that most of the china sellers hike the postage to get the income inWhen I did some research, its for sale in UK for £20,($40ish) and the one I bought is only £10, so like everything you get what you pay for, and the emax inrunner 3600kv is an amp hungry little thing, hopefullt the walkera gives better results.

I have also been experimenting with 2/3 sub c nimh, 1500mah, which so far have given slightly less performance and run time, but with the better motor might be the answer to my kids not destroying lipos! what this space..........

sundogz

Yup, those that don't follow good info are doomed to repeat the mistakes of others! But I do understand wanting to get the most from your setup. You should be looking for 30K rpm's (tops) in this boat, whatever combination of volts and KV's you want to use to do it. Remember to figure in losses due to efficiencies (I have always used a conservative 80% multiplier). So at 11.1v (3s) if you go with a 3200kv that would be 3200x11.1=35,520x80%=284160 which is in line. Actually very good. If you push that envelope too far, you will increase noise and heat but not speed.

Lapistola28: just change to a 2s (7.4v) lipo. 4800x7.4=35,520x80%=28416 which is good - should run fast and cool with a good battery (2200ma or better at 20-30c to be assured enough amps to not strain anything).

Pmdevlin: you just had to try, didn't you! No worries, that 3200 will be good and drop right in. If you want to push things a bit, go to a 24 or 28mm can size motor (you'll need to get a different coupling) or maybe an outrunner such as [link=http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=8138&Product_Name=Turnigy_2836_Brushless_EDF_Motor_3200 kv] this[/link]. You won't be straining it, and so probably won't need to cool it. There is always [link=http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=8480&Product_Name=Turnigy_2632_Brushless_Motor_3400kv]this one[/link] that will drop in (2.3mm shaft) but it will need cooling (motor mount?) and finesse (not WOT continuously) to stay healthy as you will be pushing its capabilities (my opinion).

(edited out cocky language[X(] and for accuracy[8D]) Sdg

DRAGONFIRE81M

i wouldnt if its a 20mm motor case way to much load youll just end up cooking the motor . im thanking damfurst did something like that with a mumba motor . i personly dont thank the 20mm is a good choose but thats just me . i use 24-28 mm motors .

lapistola28

thanks guys .... well back to waiting for Hobby King ........

DRAGONFIRE81M

im with you there. been waiting since feb 16. and planning another order for some edf for a air hogs glider

damfurst

Hey Dragon, I smoked a 3200kv 28mm can Emp motor on an ABC Hobby 22mm Jet Drive. I have that same motor on my mini Jet and it runs it great. The motor I'm trying now on these knock off drives in my twin jet boat I'm making is [link=http://www.hobbypartz.com/el4003brmo.html]this[/link] one. It is a little higher kv (3700) but it is a longer can and is rated at 20a burst and 18a constant (200w on 3s). Because of this and for the price I thought why not try it. I recently hooked my watts meter up to one of them and at wot (in water) it pulled about 9.5amps with a peak amps of 24a. I think they are going to work, but got to get another as one isn't working right and I narrowed it down to the motor. Anyway, the point of all this is I'm of the opinion that a motor whether it is a 20mm or 28mm is you want to look at not just the kv (2800-3200) but also at how many amps it will draw constant. My rul of thumb any more for the knock off drive is anything 15amp or less stay away from because it can become a post toasty. There's my 2 cents.

sundogz

The 3200kv Walkera motor pmdevlin is considering is a 2040 can and it will be pushed hard. Should use a full length water jacket (not coiled tubing) to keep temps down. The 4800kv marine lapistola28 is using is a 2040mm can also, but is a strong motor. My opinion is it should do fine but the[link=http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=8594&Product_Name=2848SL_3900kv_Brushless_Inrunner_%28W aterCooled%29] 28mm version[/link] might be faster (even though kv is less) as it is much more powerful. I believe it will fit the jet mounting hole spacing, but would require a 3.17 to 2.3mm coupling which might be difficult to locate. I am also a fan of using 24-28's in this boat. They don't have to work as hard.

Lapistola, [link=http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=10293&Product_Name=Turnigy_2650mAh_2S_40C_Lipo_Pack]this 40c Turnigy[/link] would be an excellent battery for your boat. Also, you should plumb the water lines to go to the esc first, then the motor, then out.

llDemonll

so do the bigger motors drain the batt's faster if they arent working as hard as the small ones? when i need a new one i may get a larger one but dont wanna hinder run-times

sundogz

In a word, yes. But will respond better and last longer. For longer run times, use a larger battery. And the highest 'C' rating you can afford. A 3s is heavier than a 2s, so a 3s 1800ma could possibly weigh the same as a 2s 2200ma.

pmdevlin

good motors on the last post sundogz, but I need to work on a budget as there are 3 boats I have to fund and all 3 have to be same spec! , so as good as they are, the price is a bit high when postage is factored in. That turnigy pack looks good and 40c, pity is HK as I had a very bad experience recently with some turnigy packs, the warranty really does not exist so its a chance that you take when buying cheapo chinese products, why cant we in UK get same products for similar prices, our tax is a rip off![:@]

Just been informed that the walkera motor is 10 days away[] so itrs the waiting game now, just got to try a new esc thats been waiting for some bullet connectors

llDemonll

i would recommend switching to deans or traxxas connectors as opposed to bullet connectors, they tend to fair much better

sundogz

Demon, Deans connectors are good for up to about 60A before they get hot and the soldered connections fail. 5.5mm bullets can handle twice that or more. Large bullets have less resistance and more conductivity than Deans at higher amps.

pmdevlin, what happened with your Turnigy packs? I've always considered them very highly.[sm=surprised.gif] BTW, I surely agree about taxes! [:@] Be sure to use a water jacket on the Walkera, or if you use coiled tubing, also use thermal conductive grease for good conductivity. That motor needs to be kept cool.

beke6874

That's what I said.

I have the 2040 Walkera motor, and I used brass for my cooling coil because that's what I had. Aluminum has a thermal conductivity of 1460 BTU-in/hr-ft²-°F and brass is 1100 BTU-in/hr-ft²-°F. Should make very little difference considering the thermal conductivity for thermal compound is much lower than that of brass. A water jacket would be by far the best way to go. I tried making my own water jacket for the motor, but it didn't work out so great. From the sounds of it, maybe I should try again. I also made a brass heat exchanger for my esc and glued it on. Has anybody else tried this? I will try to get pictures of it.

aum-offshore

pmdevlin

sundogz, I ordered a load of things from HK, including two whopper size 3 cell 5000mah 30c packs to run a big heavy scale brushless set up. Charged both packs, balanced perfect, took to lake and after 3 mins the brand new castle creations esc ($200!!!!) blew itself apart. One of the packs lost a cell causing internal resistance, for a brief moment the inertia of the drive gear kept the motor spinning for a second or two, and the volts backed into the esc.
HK where totally useless, I had to send the pack back with no refund of postage, and no compo for the esc. They then said it had not arrived, until I proved it had with thankfully recorded post, then they totally ignored all emails for two weeks, until I signed into their own forum and spent every day for the following two weeks sending messages to every HK employee I could find, till they agreed to send as replacement. I dont think it was so much the turnigy pack but more the crappy service from HK.

Chinese customer service is way different to that in UK Europe and USA, buy cheap, get cheap, we all take our chances, I hate bad service and will always pay a bit more to buy local!

As for the boat, just fitted new esc (yes, cheapo from China!), but at £8 $16 for a 50amp its worth the loss if it fails, and still waiting for the 3200kv walkera, this was supposed to be a quick cheap project, but is really dragging on now!! , work keeps getting in the way, and its dark at 6.00pm before I get home home, bring on the light nights!

jetsprintbasher976

My Feedback: (-1)

dude that sucks but why oh why would you put a castle in this  cheap ass boat. the cheap $10 mystery esc gave me better resualts than a flyermate 40amper. and know i just orderd some seaking 35amprs hopeing they wont blow from the water because me and my bro fried 4 esc this month alone and 6 total since we got into these jet boats.! anyone had a water related failure with the seakings? and to top that i fried my mmm v3 esc to in the snow not a good month . and my boat sits low with 2x 2280mah 3s can;t imagine how low yours is lol