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-   -   Mini-V flex drive & brushless (https://www.rcuniverse.com/forum/speed-electric-109/5906643-mini-v-flex-drive-brushless.html)

spicedcrab 05-26-2007 11:42 PM

Mini-V flex drive & brushless
 
1 Attachment(s)
hi, its late and im about to go to bed but i wanted to post some pics of the mini-v before i go. real quick specs, octura prop, strut, flex shaft, and drive dog. 3000kv brushless, mamba 25 esc, 3 cell lipo.

i will give more details soon when i have more time to write.

wish me luck, its almost done and i should be able to test it in a couple days.

john

mxracer154 05-26-2007 11:44 PM

RE: Mini-V flex drive & brushless
 
that hardware is way to big for that boat....Looks like the whole back end will sink when you put it in water...

eboat 05-27-2007 07:13 AM

RE: Mini-V flex drive & brushless
 
I was thinking the same thing too much weight out the back end

Wheelnut 05-27-2007 07:21 AM

RE: Mini-V flex drive & brushless
 

ORIGINAL: mxracer154

that hardware is way to big for that boat....Looks like the whole back end will sink when you put it in water...
You took the words right out of my mouth, but it may not be true, alot of fast electric boats look like they are going to sink until you get them going. I will be very interested to see a video of the first run.
Nice work just the same.

spicedcrab 05-27-2007 03:36 PM

RE: Mini-V flex drive & brushless
 
hi all,
i was kind of thinking the same also about the weight, but i wanted a drive line that would take any amount of power that i can squeeze into the boat.
i just made a test run a couple mins ago. when i put the boat in the water, the waterline rests right about were the servo rod exits out of the transom. the prop churns longer now before it bites but once it catches its planes perfectly, and the boat is very stable. i had a octura x427 prop and 2 cell lipo for the 1st test just to make sure that everything worked ok. it went at my best guess about the same speed as the boat did when it was stock running on a 3 cell lipo. after 10 mins running motor and esc were not even warm, so since it passed the 1st mild test, next i am going to step up to a x632 prop and 3 cell lipo. the prop change and extra cell should at my best guess double the output watts of the drive line.

i will keep everyone updated when i make the next test.

john

Wheelnut 05-27-2007 04:18 PM

RE: Mini-V flex drive & brushless
 
Please try and get a video for us.

spicedcrab 05-27-2007 09:25 PM

RE: Mini-V flex drive & brushless
 
hi,
i decided to do one step at a time. i put the 3 cell lipo in but left the x427 prop on. WOW its super fast now, and i cant imagine what it will do when i put the 632 prop on.

i tried to get a video for you during the test, my son was driving and taking it out real slow while making a wide turn, then was just getting ready gradually speed it up, as he got to about half throttle my camcorder stopped and said "battery" (i didnt charge the camcorder before i left) i got a total of 2 seconds of video.:( before it cut off. i will get a new video clip on the next time out so you can see what a rocket this little boat is. (what you see in the clip is only about half speed as he was just starting to squeeze the trigger.)

video >>>>> http://www.youtube.com/watch?v=iA3K30h5pPk

at full speed the boat is mostly stable but if it hits a slightly bigger than normal ripple in the water it goes flying and flipping, sometimes landing upside down and we have to retrieve it.

im going to experiment with prop angles and trim tab setting to help control it.

FE_Chris 05-28-2007 09:27 AM

RE: Mini-V flex drive & brushless
 
Niiiiiiiiiiiiiiiiiiiiiiiiiicccccccccceeee[sm=shades_smile.gif]

2 seconds or 2 minutes....thats one fast mini-v!


ORIGINAL: spicedcrab

hi,
i decided to do one step at a time. i put the 3 cell lipo in but left the x427 prop on. WOW its super fast now, and i cant imagine what it will do when i put the 632 prop on.

i tried to get a video for you during the test, my son was driving and taking it out real slow while making a wide turn, then was just getting ready gradually speed it up, as he got to about half throttle my camcorder stopped and said "battery" (i didnt charge the camcorder before i left) i got a total of 2 seconds of video.:( before it cut off. i will get a new video clip on the next time out so you can see what a rocket this little boat is. (what you see in the clip is only about half speed as he was just starting to squeeze the trigger.)

video >>>>> http://www.youtube.com/watch?v=iA3K30h5pPk

at full speed the boat is mostly stable but if it hits a slightly bigger than normal ripple in the water it goes flying and flipping, sometimes landing upside down and we have to retrieve it.

im going to experiment with prop angles and trim tab setting to help control it.

Wheelnut 05-28-2007 09:46 AM

RE: Mini-V flex drive & brushless
 
Yeh, you can tell she was getting ready to sing, the rpms were like one second from topping out. (I think). The new video will tell. But yes, that is one fast mini V. I need to decide what I am going to do with mine.
Spicedcrab, what hardware is that? Is it a set for another boat? or did you fabricate it? Details are much appreciated.

spicedcrab 05-28-2007 06:30 PM

RE: Mini-V flex drive & brushless
 
hi,

i got a longer video today. we moved the battery in front of the motor but this made the center of gravity to far forward, so we taped some foam on the front third of the hull so it made a step, to see if it helped with the new CG. we made a longer rudder to help keep it in better control. we added a foam piece on the top of the boat to see if it will self right itself. i think the step and center of gravity made it a little slower, it didnt seem as fast, even so we could still not give full throttle and keep the boat in the water, during the video we hit full throttle a couple times for a second or so, mostly we were throttling it to try and stay in control.

here is the video; http://www.youtube.com/watch?v=H_l7QkR3ZfQ

wheelnut, i will get the stock numbers of the parts i used for you, some was bought, some was fabricated. more details to come when i get a chance to look up the parts.

john

Wheelnut 05-28-2007 07:05 PM

RE: Mini-V flex drive & brushless
 
She's real fast, I see you are having the same problem I had with my Gecko, keeping it in the water. Trimming the trim tabs down a bit might help. Also maybe change the angle of the strut.

SV27dayton 05-28-2007 07:19 PM

RE: Mini-V flex drive & brushless
 
I was thinking the same thing about the strut. Amazing how stable it actually is given how seldom it's in the water.:D

spicedcrab 05-28-2007 08:36 PM

RE: Mini-V flex drive & brushless
 
wheelnut,
i bought all the parts at www.offshoreelectrics.com the strut is the octura alum for 3/16 shaft, the flex cable is .130 octura, teflon tube, alum tube over that inside the boat, the prop shaft is 3/16 turned down to 1/8. the brackets are home depot alum angle cut to length then drilled, the rudder bracket is the stock mini v strut (cut off) and then a single bolt (so it flips up if anything gets hit) holding the rudder that was cut out of the alum angle. the motor is a motor max 450TH outrunner with no cooling, 3cell 1650 lipo, mamba 25 esc (with cooling)

as far as the strut, do you suggest changing the angle down more, or lowering the whole strut deeper, or both?

thanks,
john

Wheelnut 05-29-2007 08:31 AM

RE: Mini-V flex drive & brushless
 
Thanks, first just try to angle it down some. You just want it to push the bow down a tad.

How did you turn the prop shaft down from a 3/16th to a 1/8th?

Quicksilver1 05-29-2007 10:36 AM

RE: Mini-V flex drive & brushless
 
that hardware means business, you dont even have to run her to prove it's fast as all **** :D


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