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  #31  
Old 10-31-2002, 02:55 PM
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aktiondan aktiondan is offline
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I had read about MotoCalc but didn't know it available for download. I will definitely check it out. And yeah I know it was a cheap shot comparing the 17 amps with the 1.4 amps. I could simply stall the motor and say hey look how many amps it draws, which wouldn't be totally accurate either. But plane and simple, any Speed 400 will pull more current than a 280. Yes?

Motor theory isn't something I've studied up too much on. Especially airplane motors. But it's good to know that there is a knowledge base out there where one can learn this sort of stuff. I'm sort of learning and sharing as I go along. Miha Holc, it's funny you mention that spreadsheet you made which calculates MPH for given motor/cell/gear/tire size combinations because I had done the same thing! I found it to be fairly accurate, but nearly impossible to determine an accurate loaded RPM which constantly changed for every different gear ratio chosen. It said I could get a 540 Micro up to 80MPH, which proved to be obviously wrong.

What I really want to know is how they rate those Speed 400's as 7.2V, 6V and 4.8V? Is it the wire gauge, the windings, something else? And what is the probability of failure running them above (or way above) their rated volatage? If I have to shim the comm every other time I run through a pack, I'd say NO WAY!!

-Dan

BTW, that boat was friggn' flying! I couldn't imagine what 4 wheels on the ground could do with a motor spinning that fast. I would take your word for it. Without hesitation.
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  #32  
Old 10-31-2002, 03:36 PM
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Quote:
Originally posted by aktiondan
Especially airplane motors.

.... It said I could get a 540 Micro up to 80MPH, which proved to be obviously wrong.

What I really want to know is how they rate those Speed 400's as 7.2V, 6V and 4.8V? Is it the wire gauge, the windings, something else? If I have to shim the comm every other time I run through a pack, I'd say NO WAY!!

BTW, that boat was friggn' flying! I couldn't imagine what 4 wheels on the ground could do with a motor spinning that fast. I would take your word for it. Without hesitation.
Dan, why do you say airplane motors? Motors are motors, they can be used everywhere... small, big, big torque, big rpm, etc...
I found only in r/c car industry they claim this motor was designed for blah blah... and this continued on BL motors, for example modeltech... I really wonder for exaple why doesn't some company made or designed good 12-14 cell offroad or onroad car that uses cheapo 700 motor size. This motors pack some really nice power, are very durable, but cost as much as stock 540 motor.

And that with your 540 motor project... I think the cells were the problem. 540 types suck easily 5 to 10 Amps in idle current! With this current you are done with 400 types! I mean I suppose this is the current 400 motors will pull in micro, cannot be more.

For speed 400 ratings , see www.microhydros.com I think Trent explained there all about them and gave links to mabuchi site with motor data.

About comm skimming: Boats are far more brutal on the motors. There you have constant load and what is more, corners can be just way brutal on the moments. The boat on video has surface drive, this means only half the prop is touching the water in the straight. But in the corners more water comes to the prop and motor is much more loaded. He gets 6 minutes of runtime out of 1 Ah cells, this translates into 10 Amp CONSTANT load, probably really 15+ Amps in the corners... 50 % eff ...not good for normal 400 motor.

I think for micro rs4 this should be no problem. Oh, one more thing - do you run in the motor under water? ... if not see rccaraction.com online article supercharge that stocker. I found 400 motor brushes very hard and it needs about 10 minutes of running in @ about 6 V. Just check in between (with disconnected motor!) if the brushes are fully seated. This helps tremendously in efficiency department, power and also affects overall motor life. For example I have 400 6 V motor (water uncooled!) in my micro boat and it pulls constantly 6 to 7 Amps on 7 cells. I did 50+ runs and on few of the runs motor was scorching hot! But man, this motor is durable. It still goes well, maybe only eff went little bit down. My friends who did not made water running in ruined the motor after few runs....

And one more tip, but I think from what i've seen on the photos couldn't be done on micro to little space... this is adding thin iron torque ring... it is especially helpful on 400 4.8 V race or rocket motor. Torque & eff up, rpm little bit down (but cannot be seen in driving). But maybe, you can split the ring just there where it touches rear axle.

But OK, sum it up - these motors doesn't cost a fortune and they are very fun to experiment.

Offtopic:
I want to know where are the BL guys with those Hacker B20 22S motors? I also seen somewhere someone is going for one of those beast cuties from Lehner (10xx series) ... http://www.rumrunnerhobbies.com/10_series.htm

Someday I am gonna put motor that powers one of my boats:
http://www.microhydros.com/minikiwi2.mpg

this is on 7 cells. I think I know how to pack 12 cells in a micro... hmmm I am very interested in consequences/side effects but if I manage to somehow put the power to the wheels and translate it into speed just for one sigle straight pass ...
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  #33  
Old 10-31-2002, 03:55 PM
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A friend of mine did short clip of direct 400 6 V motor vs. BL motor comparison in very very similar designed boats, 400 6 V powered boats being about 60 gram lighter! Both 7 cells:
http://siky.org/Images/slike/modelar...T/MOV00967.MPG


Regards,

Miha
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  #34  
Old 10-31-2002, 04:13 PM
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Quote:
Originally posted by RyMicroRS4

Speed 280 Race 6V(in the mail)
-Ryan
Ryan, did you tried that motor? I think it should be quite good performer. This is 280 race 6 V motor on 6 x 270 mAh 2/3 AA cells in a boat (sorry for only puting boat videos, but heck, run it 60 to 100 % faster and this is how it should do in a good setup car): http://www.microhydros.com/miha_kiwipico.mpg
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  #35  
Old 10-31-2002, 04:24 PM
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Quote:
Originally posted by Miha Holc


Ryan, did you tried that motor? I think it should be quite good performer. This is 280 race 6 V motor on 6 x 270 mAh 2/3 AA cells in a boat (sorry for only puting boat videos, but heck, run it 60 to 100 % faster and this is how it should do in a good setup car): http://www.microhydros.com/miha_kiwipico.mpg
I haven't tried the 280 race motor yet. Should be here anyday now. I am gonna run it on a 8 cell pack. I hope it does run fast. I'll run it as a 140mm wheelbase setup with a VW bug body. That should keep it looking very sleeper like, until I put it on the ground.
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  #36  
Old 10-31-2002, 05:14 PM
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I call them airplane motors because after calling 4 hobby shops in town, I finally find the only one that carries Graupner Speed 400's and the lady says, "All we carry is airplane stuff! We're 90% electric planes!" But yeah, a motor's a motor. And those boats are wicked fast. You know I have never broken in a motor underwater, but I think I have that issue of RC Car Action at home that talks about it. I'll give it a try on my new motor I'm going to pick up this weekend. I think I'll go with the Speed 400 6V but I kinda want to get the 4.8V race or the rocket. I'll see what they've got. I've got to get a new set of rims and tires too because mine are torn to shreads and completely undrivable.

Hey Miha, you mind if I "steal" some of your info and include it on my site? Let me know. And Ryan, when is your 4.8V Race going to get to you???? I'm hoping my LHS will just have a few. Hobby-Lobby isn't getting $7 out of me to ship a $10 motor!


-Dan
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  #37  
Old 10-31-2002, 05:35 PM
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Dan, feel free ... I am glad I can help at least one of you.

BTW, if you think these boats are wicked fast, look here:
http://www.drcwebservices.com/lasaw/
http://www.drcwebservices.com/lasaw/pictures.htm

I am flying to LA in less than a week to attend this straightaway event with my two boats (18 and 24 cells) . This year it is expected to be another brakethrough in fast electric boat history -first boat over 100 mph! Some rumors say that actually 100 mph will be smashed. Man, if someone would really dig into this and put this kind of power into good setup ultra custom four wheel thing ... I just couldn't imagine what it would be. 99% people wouldn't believe it is electric powered

Furthermore, OK, please excuse me going again too far from the topic, but future in electrics does look bright, brighter than we could all imagine - new breathtaking cell technologies are only a couple of years away.... meaning that electric power will soon dominate all the other ways of power methods. Micros running all day long won't be anything special...
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  #38  
Old 10-31-2002, 05:42 PM
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Yea, lithium cells for one, I can not wait for novak to come out with their $89 li-ion charger + 7.6volt battery pack setup.

Then I can use the $4/pack batterys from the same place I get my brick cells and have an unbelievably fast car, using 2 cells !
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  #39  
Old 10-31-2002, 06:01 PM
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Lithium polymer cells are just the first step.

Why to wait for Novak?


https://www.fmadirect.com/site/fma.h...roducts&cat=12

Some airplane guys on www.ezonemag.com did very good tests and for micros, they are already suitable cells.

For example:

Kokam Li-Poly Battery
Kokam 1020 mAh Lithium Polymer Single Cell with Solder Tabs
Size: 62mmH x 34mmW x 5.45mmT
Weight: 20.5 grams

$8.95


Two of these in series make 1 Ah, ~ 7.4 V but weight mere 40 grams. Can be loaded up to 5 Amps - stock motors, 280 motors, Team Orion coreless, but no speed 300. Price is nice

Have two of such packs in parallel you got 2+ Ah, more voltage than 6 cells but weight of good 3 AA's, and can survive 300 motor

But there is very much research going on with carbon nanotubes. Due to immense surface, cells based on nanotubes construction are predicted to pack energy densities of 1Ah/1 gram...
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  #40  
Old 10-31-2002, 06:19 PM
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batterys I can locate fine.

getting a charger that is of high quality is another thing, sure I could make a hack job with my JVC camcorder charger, but whats the fun in that? overnight charges? blah...
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  #41  
Old 10-31-2002, 06:50 PM
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http://www.drcwebservices.com/lasaw/pictures.htm

Forget the Micro....I'm getting a Hydro!!!!! How about a Micro Hydro! No? Ah, alright.
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  #42  
Old 11-01-2002, 12:01 AM
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Dan,
If your LHS has the 400 4.8V race....by all means go for it. It may take another week to arrive. I'll play with the 280 race 6V when it comes.

Miha,
Those videos are pretty cool!
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  #43  
Old 11-01-2002, 02:24 AM
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I just got done digging around in my big ol' box of airplane motors, came up with 2 promising (never used?! damn me...lol) finds

Diamond Modelsport - Speed machine MAX 480 / 7.2v
stock # - 22908

and then of course my brushless setup (which will never fit in the micro, lol)

Jeti Model - Phasor 15 - 3
36x37mm 3 turns, 0,025ohms resistance, weight=136g, shaft size is 5mm

I think my micro would catch flight with either of those motors, lol! I will take pics of them next to a speed 300 in a bit, my dad stole the digi-cam so it will have to wait
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  #44  
Old 11-01-2002, 09:34 AM
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aktiondan aktiondan is offline
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BLiND, according to the specs of 480 motors, the can is only like 1.5mm larger than the 380 and like 9mm longer, but still should fit within the width of the rear hubs. You may need to make a custom motor plate though, but then again, maybe not.

I'm going to hit a few hobby shops today. Pick up a Speed 400 ?.?V. I probably won't get the 4.8V race because I know it won't last very long running 9.6V. So I may try the 6V first.

Oh and if you want to know the constant of the Watt-Age $7.50 motor for gearboxes it's 2321 RPM/V. Which means at 9.6V I was only seeing 22,281 RPM's and yet my Micro was super fast. I can't imagine what a motor with a constant like 4450 RPM/V could do on even 8.4V. It's gonna be great. I'll let everybody know later this afternoon.

-Dan
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  #45  
Old 11-01-2002, 11:45 AM
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Miha Holc Miha Holc is offline
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http://yourmicro.com/forums/attachment.php?postid=30821

Here is my brushless B20 15L compared to two 280's and 400 with torque ring (don't bother the stickers). B20 15L was meant for direct replacement for speed 400 so it has also same mounting holes.

Oh, here is one more comparison for B20 15L or 18 L vs Speed 400 6 V in the same model pylon airplane :

400 6 V, 8 x N500AR ~ 90 mph
B20 18L, 8 x N500AR ~ 125 mph
B20 15L, 8 x N700AR, ~143 mph

Some 400 info:
http://www.microhydros.com/400_motor_complete_info.htm

Dan, keep us posted! And if you can shoot some video footage!

Last edited by Miha Holc; 11-01-2002 at 11:57 AM.
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