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-   -   Brushless Balaenoptera Musculus (http://www.rcuniverse.com/forum/speed-electric-109/11287828-brushless-balaenoptera-musculus.html)

seehuusen 11-05-2012 03:20 PM

Brushless Balaenoptera Musculus
1 Attachment(s)
<div>Hey fellow modders :-)</div><div></div><div>I have gone and purchased another toy boat to mod</div><div>I really like building these boats; it gives me no end of pleasure.</div><div>It&rsquo;s relaxing to sit at home with a beer, some music and modify these boats, then take them out and see how much better they run. Bring back home, repair something or modify the boat further, just to squeeze a bit more out of it, I love it :-)</div><div></div><div>Damfurst on this forum started an awesome build with dual brushless motors, using the original drive train. I&rsquo;m wanting a single motor, I think it&rsquo;ll be easier to maintain and build (plus that&rsquo;s what I&rsquo;d want anyway)</div><div></div><div>The plan is to run a 3/16inch flex shaft setup to a strudder (stinger with a rudder behind it)</div><div>I&rsquo;ve heard people say lots of confusing things about the flex setup, and because this is my first ever prop boat, I&rsquo;m probably not understanding the advice.</div><div>The general thing I understood were the parts involved, but sizes seems a bit odd.. With some shops only selling certain bits?!? Anyways, I found this listing, and that&rsquo;s what I believe I&rsquo;ll be going with</div><div>
</div><div>The kit contains everything I need, so I can learn all the bits and how they work together</div><div></div><div>Motor wise for this thing, I&rsquo;m thinking something in between 2860 and 3660&hellip; It just depends what sort of Kv rated motors I can get&hellip; 2500Kv on 3S and 3300Kv on 2S seems to be the goal</div><div></div><div>I&rsquo;ve gutted the boat, and sanded it down. I&rsquo;m going to put some putty in all the little cast holes</div><div>I really want a 100% smooth bottom surface, as I&rsquo;d like to hit 50+ km/h with this thing ;)</div><div></div><div>Cheers</div><div>Martin</div>

SkR8Pn 11-05-2012 07:50 PM

RE: Brushless Balaenoptera Musculus
Yeeooow "The Blue Whale" only to be used in water!..http://www.rcuniverse.com/forum/js/f...sn/biggrin.gif

Looks the goods mate, i'm watching what your doing as i don't have a clue on prop boats....lol

50+k's should be sweet. looks as tho you've been busy, man i hate sanding!
Inside hull pics would be good once you get the chance also.

*delete M i k e u p delete* 11-07-2012 07:43 AM

RE: Brushless Balaenoptera Musculus
I'm done.

seehuusen 11-07-2012 03:14 PM

RE: Brushless Balaenoptera Musculus
Mikeup you are a f..in legend!!! :D That information is GOLD! In fact, I've copied it in case it went away due to a crash!!<div>
</div><div>I am totally keen for offset rudder now that you mention maintenance (as I am not hesitant to run my gear in salt water)</div><div>When looking for rudders, I must ask, what do I need to look for? Does it have to be further back than the prop?</div><div>
</div><div>e.g. if I went with a stinger, say 70mm or so long, would the rudder HAVE to be behind the prop on the stinger? (checking to find out how long it needs to extend back)</div><div>
</div><div>Thanks again for parting with your knowledge, I really appreciate it :D</div><div>

*delete M i k e u p delete* 11-07-2012 07:12 PM

RE: Brushless Balaenoptera Musculus
I'm done.

seehuusen 11-07-2012 09:06 PM

RE: Brushless Balaenoptera Musculus
Mike, you are a wealth of information!!! Thanks so much for parting with it :)<div>I will do some research and post up some new rudder/drive train combos</div><div>

seehuusen 11-08-2012 01:04 PM

RE: Brushless Balaenoptera Musculus
Hi Mike,<div>
</div><div>I went to Hobbyking to see what stuff they might have, and I'd like your oppinion please :)</div><div>
</div><div>Rudder: http://www.hobbyking.com/hobbyking/s...t_Rudder_.html</div><div>http://www.hobbyking.com/hobbyking/s.../HK-502B22.jpg
</div><div>stinger http://www.hobbyking.com/hobbyking/s...e_Silver_.html</div><div>http://www.hobbyking.com/hobbyking/s.../HK-503B52.jpg
</div><div>The transom on the boat is bowed, so I'd need to make a small mounting pod for the stinger, which should push it out the few extra mm if required</div><div>
</div><div>What do you guys think?</div><div>

seehuusen 11-08-2012 01:15 PM

RE: Brushless Balaenoptera Musculus
I also found a potential motor<div>
</div><div>and a bit more information</div><div>

*delete M i k e u p delete* 11-10-2012 04:51 PM

RE: Brushless Balaenoptera Musculus
I'm done.

seehuusen 11-11-2012 12:00 PM

RE: Brushless Balaenoptera Musculus
LOL Mike, your message cracked me up :) Thanks for your research and time :)

<div>If I followed Mike right, using the Hobbyking stringer and rudder I suggested above, should do the trick :)</div><div>By adding a small pod for the stinger, I can' move the exit of it, back 9mm or so, in line with the leading edge on the rudder.</div><div>
</div><div>I'll get those parts and the motor shipped over this week, then I'll figure out this flex shaft assembly, which is still somewhat fuzzy for me... </div><div>(When I get the stringer drive it'll be clearer, as that's the part I don't get, if they are made for a specific sized tube, or you space that out with sleeving the inside...)</div><div>
</div><div>Someone please clear it up for me :D is it stRinger or stinger? I've seen both...</div><div>

*delete M i k e u p delete* 11-11-2012 02:09 PM

RE: Brushless Balaenoptera Musculus
I'm done.

seehuusen 11-15-2012 12:49 PM

RE: Brushless Balaenoptera Musculus
I'm looking at buying hardware today :)<div>
</div><div>What is a 6 pitch prop?</div>

seehuusen 11-15-2012 02:54 PM

RE: Brushless Balaenoptera Musculus
OK, the list is nearly complete... Boat is intended for 3S<div>
</div><div>Motor: </div><blockquote style="margin: 0 0 0 40px; border: none; padding: 0px;"><div>XK3665-B-2500KV Brushless Inrunner</div></blockquote><blockquote style="margin: 0 0 0 40px; border: none; padding: 0px;"><div><div>36 Size Adjustable Motor Mount with Water Cooling</div></div><div><div>Water Cooling Jacket for 36mm Brushless Motor</div></div><div><div>
</div></div></blockquote><div><div>ESC:</div></div><blockquote style="margin: 0 0 0 40px; border: none; padding: 0px;"><div><div>Not sure, will update</div></div></blockquote><div><div>
</div><div>Running Gear:</div></div><blockquote style="margin: 0 0 0 40px; border: none; padding: 0px;"><div><div>all 4mm gear</div></div><div><div>Flex cable with end (approx 300mm long)</div></div><div><div>Outer tube (Use with teflon liner, 300mm long, 6mm x 0.2mm thick)</div></div><div><div>Drive dog</div></div><div><div>Threaded prop nut</div></div><div><div>Teflon thrust washer (to use between drive dog and strut end)</div></div><div><div>Teflon liner (Suits 4mm cables, 300mm long, 4.5mm id x 5.5mm od)</div></div></blockquote><div><div>
</div><div>This is paired up to a 70mm long 4mm adjustable Stinger</div><div>
</div><div>Rudder:</div></div><blockquote style="margin: 0 0 0 40px; border: none; padding: 0px;"><div><div>130mm X 32mm wide Rudder dual pickup version (130mm deep X 75mm offset rudder with dual pickups, Uses kick back funtion for safety, mounting bolts included)</div></div></blockquote><div>
</div><div><blockquote style="margin: 0 0 0 40px; border: none; padding: 0px;"><div>Servo arm, piano wire or what ever</div><div>Servo arm boot</div><div>Metal Gear Digital Servo - MG995 - 15kg thrust</div></blockquote>
</div><div>Props:</div><div><blockquote style="margin: 0 0 0 40px; border: none; padding: 0px;"><div>???? 33mm - 36mm at what pitch? 1.4? I want to buy a small selection of props, preferably plastic, that I can then test out, and buy the better cnc prop after that...</div></blockquote>
</div><div>What do you guys reckon?</div><div>

*delete M i k e u p delete* 11-15-2012 03:32 PM

RE: Brushless Balaenoptera Musculus
I'm done.

seehuusen 11-15-2012 04:30 PM

RE: Brushless Balaenoptera Musculus
Hi Mike,<div></div><div>I found those on OSE, and then I thought to myself, I really aught to do myself a favour and figure out what 6 pitch is... I got it ;) (http://www.modelpowerboat.com/conten...136-propellers)</div><div>Using your graupner as an example:Diameter 36mm, Pitch 57mm. This is nearly the same as: 36 x 1.6 x 4mm prop</div><div><div></div></div><div>Now to find some over this side of the pond, coz at $21 shipping, they are a bit too expensive...</div><div></div><div>Could I go a larger sized diameter with a 1.4 pitch, or does that put too much strain on the motor?
Or should I go the smaller diameter, but with a bigger pitch?</div><div></div><div>Cheers</div><div>Martin</div>

seehuusen 11-15-2012 04:33 PM

RE: Brushless Balaenoptera Musculus
also, I know from my ski boat, more blades gives a better hole-shot, e.g. faster acceleration and better turning... I doubt it's desired in an R/C boat, but what are the pros/cons?

seehuusen 11-15-2012 04:38 PM

RE: Brushless Balaenoptera Musculus
here's one... maybe? gotta drill out to 4mm hole size, but that'd be OK<div>
</div><div><div><font size="3">35mm 2 Blade EP CNC Boat Prop (P1.7 D1/8x2)</font></div></div><div>http://www.hobbyking.com/hobbyking/s...5P17D18(1).jpg</div><div><div>
</div><div>Light weight and precision CNC machined.</div><div>
</div><div>Shaft: 3.25mm</div><div>Weight: 1.6gram</div><div>

*delete M i k e u p delete* 11-15-2012 05:59 PM

RE: Brushless Balaenoptera Musculus
I'm done.

seehuusen 11-15-2012 06:02 PM

RE: Brushless Balaenoptera Musculus
maybe I'll get it later, just placed an order for the lot!!!! :D
<div>Thanks again for your explanations... I ended up gettting a 37mm 1.4 pitch prop... Had to have something LOL ;) (I'll research for other shops here in Oz)
</div><div>~$300 all up, with postage... It's a little more than I wanted to spend, but I wanted it... So what can you do? ;)</div><div></div><div><div>MOTOR:</div><div><span style="white-space: pre;"> </span>XK3665-B-2500KV Brushless Inrunner - $39.13 (HK)</div><div><span style="white-space: pre;"> </span>Shaft Adapter - 5mm motor shaft to 4mm Flexi Shaft - $4.96</div><div><span style="white-space: pre;"> </span>36 Size Adjustable Motor Mount with Water Cooling - $14.99 (ebay)</div><div><span style="white-space: pre;"> </span>Water Cooling Jacket for 36mm Brushless Motor - $16.69 (ebay)</div><div></div><div>ESC:</div><div><span style="white-space: pre;"> </span>Turnigy Aquastar 120A Watercooled ESC $69.56 (HK)</div><div><span style="white-space: pre;"> </span>Water Outlet Barb - $2.99 (ebay)</div><div></div><div>Servo:</div><div><span style="white-space: pre;"> </span>Metal Gear Digital MG995 - 15kg - $7.83 (ebay)</div><div><span style="white-space: pre;"> </span>Flex-Rod Boots - $1.14 (HK)</div><div><span style="white-space: pre;"> </span>Servo Con-Rod for Boat Rudder $2.47 (HK)</div><div><span style="white-space: pre;"> </span></div><div>Running gear:</div><div>All from RC Boat Bitz, South Australia</div><div> 4mm drive dog<span style="white-space: pre;"> </span>$3.00</div><div> 4mm outer tube<span style="white-space: pre;"> </span>$4.00</div><div> 4mm threaded prop nut<span style="white-space: pre;"> </span>$3.00</div><div> 4mm flex cable with end<span style="white-space: pre;"> </span>$15.00</div><div> 4mm teflon liner<span style="white-space: pre;"> </span>$4.00</div><div> 130mm Rudder dual pickup version<span style="white-space: pre;"> </span>$38.50</div><div> Stinger 70mm long 4mm adjustable<span style="white-space: pre;"> </span>$25.00</div><div> 4mm teflon thrust washer<span style="white-space: pre;"> </span>$1.00</div><div> 37 x 1.4 x 4mm prop<span style="white-space: pre;"> </span>$15.00</div></div>

SkR8Pn 11-15-2012 06:42 PM

RE: Brushless Balaenoptera Musculus
Good to see the project moving ahead Martin. I've realised that i need a lot of schooling on prop boats thats for sure.

seehuusen 11-15-2012 08:21 PM

RE: Brushless Balaenoptera Musculus
LOL, Mike's your man!! :)<div></div><div>In all fairness, once you figure out how to read the different prop numbers, it's a bit simpler...</div><div>The site I quoted above, has that part down pat!</div><div></div><div>Understanding diameter of the prop and pitch (which is the distance the prop travels forward on 1 revolution, theoretically) and shape is pretty much all there was to it...</div><div></div><div>To get the top speed, I believe Mike did the following calculation</div><div></div><div>33mm diameter at 1.6 pitch (calculated pitch x diameter = distance travelled by one revolution) would yield</div><div><span style="white-space:pre"> </span></div><div><span style="white-space:pre"> </span>33 x 1.6 = 52.8mm/ revolution</div><div><span style="white-space:pre"> </span>2500KV motor @ 11.1 volt = 27750rpm at full throttle</div><div><span style="white-space:pre"> </span>27750rpm x 52.8mm = 1465200 mm/minute</div><div></div><div>Converting this to a bit easier figure = 87.912 km/h THEORETICALLY</div><div>However, in reality, the prop slips in the water, and so you loose anywhere between 15% - 30%, so 67.6 km/h is possible...</div><div>The shape of the prop, determines it's efficiency to a large degree</div><div></div><div>Other factors play in at these speeds as well, coz now you have tremendous drag from the hull to think of, plus that massive fin, total weight, water conditions etc</div><div></div><div>I'd really like to figure out what the heck the different diameter has an effect, I think it pushes more water, so you'd think higher speed. I think it comes at the cost of engine heat... anyone care to clarify? :)</div><div></div><div>Cheers</div><div>Martin</div><div>
PS. I'll bring my boat down to Brissy when I've built it, can show it all to you then ;) I'm sure I've got a fair bit to learn yet :p</div>

seehuusen 11-15-2012 08:28 PM

RE: Brushless Balaenoptera Musculus
oooooooooohhhhh * SLAPS OWN FOREHEAD*<div></div><div>ofcourse!!</div><div></div><div>if you have a larger diameter prop, it will travel further per RPM at the same pitch compared to a smaller diameter prop</div><div></div><div>e.g.</div><div>33mm x 1.6p vs 37mm x 1.6p = 52.8mm vs 59.2mm per revolution</div><div>
The prop I purchased, 37mm x 1.4p = 51.8mm/revolution, which equates to a theoretical top speed of86.247 km/h, so still capable of ~50+ km/h
Hoping the motor doesn't get too hot ;)
</div><div>Thanks brain... it's Friday, I need a drink hahaha</div>

Goldenduff 11-16-2012 05:34 AM

RE: Brushless Balaenoptera Musculus
In RC planes the pitch determines top speed the diameter determines thrust.

There is no point having a very high pitch (good top speed) if there is not enough thrust (diameter) to get you there.

Diameter= thrust/acceleration.

*delete M i k e u p delete* 11-16-2012 06:47 AM

RE: Brushless Balaenoptera Musculus
I'm done.

seehuusen 11-16-2012 01:27 PM

RE: Brushless Balaenoptera Musculus
cheers Mike :) I've got a hight quality 120amp ESC, which I've tried and tested before, it should muster whatever that 36mm motor can demand ;)<div>As for prop size, thanks for the clarification, I thought there would be more work for the motor with a larger prop... I'll get some more when they become available, I like experimenting anyway</div><div>

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