skymaster62

All done 2200kv 3s and 2s. 3900 kv

itsfishi

ok fair enough no answers, after doing some reading (quite alot) i realise why. this is what i think i will go with, any input appreciated thanks

batts are 2s 2200mah 25-50c nanos http://www.hobbyking.com/hobbyking/s...dProduct=11910

motor 2040 4800kv http://www.hobbyking.com/hobbyking/s...erCooled_.html

esc 50 amp cheap cheap http://www.hobbyking.com/hobbyking/s..._w_3A_BEC.html

would really prefer to go a bigger 28 size motor but having trouble finding something with high enough kv for 2s. any suggestions please.

what would be the lowest kv that you reckon would still be good on 2s, those ads watercooled outrunners look good but highest kv is 3700.

thanks any input would be great

cheers

sundogz

The problem with 28mm motors isn't the rpm range, it's finding a coupler to fit. Here's a nice 28mm [link=http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=8594]motor[/link] that's quite worthy, even on 2S. But finding a suitable coupler is another thing. If you've read the thread, you'll see others have resorted to drilling out the factory coupler or having one made somewhere, with varying results.

skymaster62

Cornwall boats in th UK has graupner couplers. You can buy a 3.2mm to 2.0mm and a 3.0mm to 2.3mm and split them (at the u-joint)to match your needs. That is what I did.

sundogz

Skymaster, does the u-joint fit in the channel where the coupling fit, or did you have to modify it? Can you post a pic of the jet drive and u-joint?) Thx, Sdg.

skymaster62

I will post a picture tonight. The coupler fits very neatly. I just put a little marine grease in side the shaft housing behind the seal and smeared a little on the coupler itself just for good measure. The set screws might touch a lttle under load but they take care of themselves after a few rpms (hence the grease on the coulper).

itsfishi

thanks guys. yeah i actually have one of those motors, used to use it on a surfer (overworked for that app. in my oppinnion) but dont think it works anymore. as for couplers a mate has a lathe so i will go down that route.
am actually very interested in using one of these type motors http://www.hobbyking.com/hobbyking/s...00kv_600w.html
but going on what ive read the rpm will be to low on 2s , just under 22000 at 80% eff. they just seem like a good idea to me, less than half the weight of that 28 size 3900kv built in cooling.and outrunner. what do you guys reckon?
other idea i had is use this one http://www.hobbyking.com/hobbyking/s...tor_Boat_.html
but with 2 x 2200mah 2s in series so 4s giving just under 38000 rpm at 80% eff. and dialling down the end point point on throttle. but would using 2 batts be 2 heavy (240grams total batt).

what do you guys think about these options thanks.

skymaster62

Sorry about the picture quality. I mho the GoPro is not worth $300.00. Cornwall coupler.

skymaster62

Twomore for refrence.

ISIRC10

GoPro is worth the money (at least when I got it was $200) - it is a video camera for extreme conditions, so obviously it will be outclassed by a point and shoot in a everyday photo shoot... wait till you take it places you wouldn't take any other video camera

sundogz

Itsfishi, I've been waiting for someone to try that 3700kv outrunner in this boat. It has plenty of power and torque, and should be respectable on 2S. The 3200 on 4S is overkill, IMO. But would be fine on 3S. I run a 2900kv (600w) on 3S and hole shots are powerful.

Skymaster, you did shoehorn in that u-joint after all. How much was the two u-joints and shipping (if you don't mind me asking)? You might post the part numbers so others can take advantage of that arrangement. That will save someones project, for sure.

ISIRC10 knows his stuff about taking movies - I've seen some of them. Excellent work, fun to watch.

itsfishi

thanks sdgz its just that i already own 21 2s 2200mah batts and just cant bring myself to buy 3s batts. if i didnt have all those 2s i would be going str8 for 3s setup. so you reckon that 3700kv should be good on 2s.
if you had to choose between the 2040 4800kv setup or the ads400 3700kv both on 2s what would you go with.

id really like to try that 3700 but the 4800 has proven success and takes less mods to fit. hmmm what to do????? maybe i will do 1 of each since im doing 2 boats.

thanks again for the help, keep up the good work.

skymaster62

I didn't save the packing list, so I don't have the part # but it is easy to pick them out on the web site. They drop right in. Line up the impeller in the stator for a close fit and green lock tite the set screws and lube. I would like a little more speed out of mine, but it is fun none the less. Need to get it in a current. Not a tech guy, so I have a tough time posting web sites. Less than $20.00 shipped for 2 sets. I don't notice any real vibration. Pretty smooth.

skymaster62

Can you purchase diffrent lenses for the GoPro?

ISIRC10

I find that the still pictures from the gopro leave a lot to be desired - too much fisheye. This can of course be handled in post processing using photoshop or a similar editing program, however, I use the gopro to primarily shoot HD video where the camera is put into extreme situations (aka water, rocks, or 30 foot drops from a tricopter). Shoot in 1080p because the fov angle is smaller that way, reducing the fisheye effect (which is really visible in 720 and 960 resolutions). Now with the extensive marketing campaign the price of the gopro has gone up, but I still think it is a fairly good deal. It has good clarity and is good at adapting to changing light conditions (hence its popularity in fpv applications). I did see an aftermarket lense some time ago - however in my opinion it is overpriced and rather crudely made. My advice - having used it for about a year and a half now, is to use a point and shoot for documentation and the gopro for video (however, its lack of zoom makes positioning vital)

An example of one of my videos:
http://www.youtube.com/watch?v=0XRxAIavQhs

sundogz

The 2040 4800 doesn't have enough power to overcome backpressure, so it can experience a 'point of no returns' at about 3/4 throttle. It would not be my choice. If I had to go with a 2040, it would be 4500kv or less. The ads400 3700kv hasn't been tried, so I can't say. But I have suspected that it would be a good candidate. The only factor being the water filter they supply with the motor - suggesting tiny sand particles might impair performance because of the water channels contact with vital parts. Or it might just be the small channels might become clogged easily. Don't really know, but I would be very interested in a build with this motor.

swervyn

great vid!

ISIRC10

Thanks, I have as much fun making videos as I do making models - its how I can share my models with the rest of the world!

itsfishi

i will try that ads 400 3700kv when i do mine and let you know how it goes.

thanks for the help.

murmuzy-tearinto

Well I've had some time to make a video or two of my boat now. It's functioning pretty well with it's marker cap steering nozzle. here it is: AWESOMEVIDEO

Thanks to everyone on this forum that was able to share some knowledge with me to help get this done.

sundogz

I would say that is pretty fast! Great idea for a replacement nozzle. That aeration when in rough water (in the first video) could be caused by air entering though the shaft bore. If so, a good sticky marine grease will fix that. Coat the shaft with a thin layer and prime the bore a little as well. Good show.[sm=thumbs_up.gif]

boatbandit2

Hi

I was wondering if any would be able to help me as my jet boat cavitating at full trottle maybe i need to move my batt further back or should i make a ride plate
my boat has a 4800kv motor with a 35amp speed controller Please can someone help as i am new to jet boats

murmuzy-tearinto

thanks,

after I took the first video I got it stuck on a rock about 50 feet out from shore. while I was up to my chest in 7 degree weather I noticed i'd been driving through patches of water grass, I had to clear it off the grate a lot and it was causing a lot of cavitation. I'm thinking i'll make a running plate with a drilled screen instead of the mesh i have on there now. I'm thinking if Idrill the holes on an angle it'll give each hole a small amount of 'scoop' and should allow for great water flow.

sullivanmd

HI I see you Bought the Graupner Mini Jet 2349, my question to you is did you have to do any modifying or anything to make it work with your motor. I know when I bought my NQDTear Into I bought a2040SL 4800kv Inrunner that has ashaft diameter of 2.3Will the GraupnerMini Jetwork with what i have if it comes with a 3mm shaft? I'm just confused and also did you buy extra 19mm impellers incase they break on you? Thanks alot.-

sivad2

new on here lookiing to get one can't find them in the usa. please help

thanks
matt