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Unhappy Cub

Old 03-13-2011, 01:55 PM
  #1  
kevinm
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decided to check my 2600kv Dynam super cub on the HK-010 wattmeter last night and sure enough, the motor is supplying 100 watts at 8A full throttle-similar power system (but the Cub has a different make n model , different motor)(pedastal mount) on 4 of my other planes gives a hair raising 265 watts @ 18A hot glued and screwed to the perch of the Wild Hawk, etc
i tried 3 different batteries, all showed approx, 100 watts, so that leaves the esc or motor -(or solder connections that arent suspect )

this is a true no- brand yellow 30 a esc - http://cgi.ebay.com/Motor-Speed-Cont...item483f8712ce
<<< is there a chance it needs to be programmed to allow full voltage to the mot or?>>>

i have always ran Mystery 30a escs, plug n play, no smoke,
just at the point now i have no extra motor or esc to install for a check - so thought maybe this esc isnt plug n play

Last edited by kevinm; 03-13-2011 at 04:18 PM.
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Old 03-13-2011, 03:29 PM
  #2  
dumo01
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[QUOTE=kevinm;792301]similar power system on 4 of my other planes gives a hair raising 265 watts @ 18A hot glued and screwed to the perch of the Wild Hawk, etc
i tried 3 different batteries, all showed approx, 100 watts, so that leaves the esc or motor -



The other 4 planes all have the same prop as the suspect plane?
Have you ever measured this plane before? Is this a new development because the planes flight characteristics changed or you were looking at it just to find out?
Tough to say much with out knowing more about what is going on, but prop-ing up will give more power with an and increase in current draw... in this case that my or may not be a good thing.
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Old 03-13-2011, 04:08 PM
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kevinm
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all wearing a apc 6x4 sport- sorry forgot to mention -its sitting at 8 amps full throttle so up propping could be considered but the rpms just arent there with a 6x4 so rpms would fall drastic with more prop- the other 4 planes get up toward 20a @ full throttle - i bit the bullet and ordered a new 2600kv of the identical make and model of my other good motors - this isnt the first stick pedestal mount motor ive gotten that claimed to be a certain power rating and didnt produce - thanks fopr the reply -itll be a few weeks for the Cub to be sitting waiting -- im guessing the esc is OK, providing all the voltage it can, if i remember right, the voltage drop on the full throttle static runs were .5 volt, from zero to full throttle - i really like this HK-010
heres a link to my good motors
http://cgi.ebay.com/Brushless-Motor-...item3f07a51c54
i cant even find a link to the motor in question -
all this said , i know there are more correct motors for a Cub- i tried , with no success to get a powertrain to include a 9" prop but it was a fail - rctimer claimed 300 watts out of the 1200 kv motor i got and it wouldnt take off - tip stall & crash from 3 foot altitude
http://cgi.ebay.com/New-RC-Timer-282...item1c0c4b4bb0 can anyone tell me why i didnt get 300 watts out of that motor with the suggested lipo and prop?? shouldnt 300 watts convert to much more power than needed for a foamy Cub? 950 grams is over 2 lbs of pull so i dont know what was wrong --the lipo C rating too low? (20-25c)?
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Old 03-13-2011, 06:25 PM
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That's basically wildly unrealistic specifications. Just look at the numbers :

It only take a 3S lipo, about 11V under load and the maximum current is 18A. 11V x 18A is only 198W. So how they rate it at 300W is anyone's guess .

BTW you don't say but I hope you were running a 3S lipo. 2S would naturally give you a lot less power.

Steve
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Old 03-15-2011, 12:07 AM
  #5  
Dr Kiwi
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http://cgi.ebay.com/New-RC-Timer-282...item1c0c4b4bb0 can anyone tell me why i didnt get 300 watts out of that motor with the suggested lipo and prop?? shouldnt 300 watts convert to much more power than needed for a foamy Cub? 950 grams is over 2 lbs of pull so i dont know what was wrong --the lipo C rating too low? (20-25c)?

It is a 50g motor!!!!!! At best you should look for 150W (3W/g).... if you thrash the hell out it.... maybe 200W.

This link: http://cgi.ebay.com/Brushless-Motor-...item3f07a51c54

is for the 2600Kv motor (essentially a Suppo 2208/8)... with a 6x4 on 3s that would draw close to 25A and fry!
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Old 03-15-2011, 12:33 AM
  #6  
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well, i dont know what im doing wrong, but its a happy setup with a 6x4 on 11.1, my hk-010 shows its @ 260 watts @ full throttle @ less than 15A
260 watts out of a 47G motor i like - its been doing it over a year
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Old 03-15-2011, 12:40 AM
  #7  
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Originally Posted by slipstick View Post
That's basically wildly unrealistic specifications. Just look at the numbers :

It only take a 3S lipo, about 11V under load and the maximum current is 18A. 11V x 18A is only 198W. So how they rate it at 300W is anyone's guess .

BTW you don't say but I hope you were running a 3S lipo. 2S would naturally give you a lot less power.

Steve
yeah i shelved that motor as a future 4S experiment lol - hate that when parts are misrepresented- wastes my time -
RCTimer, too ! lot of ppl get stuff from them, i thought id go the long(er) dollar fixing this Cub it didnt pan out (yet)- 260 watt 2600kv is on the way
anyone ever had a wattmeter read wrong? i believe its right on , according to how much stuff is flying around the room when i static test it with its 6x4 on -- watts = Amps x volts, but its variable with the shaft resistance (prop)
Dr. Kiwi-- i was suspicious about the (1200kv) rctimer 50G motor producing 300 watts at 11.1 but my "buy" finger had a mind of its own -
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Old 03-15-2011, 01:50 AM
  #8  
kevinm
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[QUOTE=dumo01;792317]
Originally Posted by kevinm View Post
similar power system on 4 of my other planes gives a hair raising 265 watts @ 18A hot glued and screwed to the perch of the Wild Hawk, etc
i tried 3 different batteries, all showed approx, 100 watts, so that leaves the esc or motor -
Originally Posted by kevinm View Post


The other 4 planes all have the same prop as the suspect plane?
Have you ever measured this plane before? Is this a new development because the planes flight characteristics changed or you were looking at it just to find out?
Tough to say much with out knowing more about what is going on, but prop-ing up will give more power with an and increase in current draw... in this case that my or may not be a good thing.
measured it cuz it didnt have enuff power to take off - no brand motor - not generating the rpms it is supposed to -the possibilities are pretty confusing and when parts dont measure up it makes it harder - really really wanted a 9-10" prop on that Cub but im not good at "scale" tipstall prone power - if its stalling, i like powering out ! (im not a good scale flyer)
i just havent found a motor that gave over 250 watts wearing a 9-10" prop -havent looked in the right places ) thought i had it goin on with that 1200 rctimer- but the stock motor was several hundred kv more than 1200 and it wasnt good enough for the slightly modded porcine Cub- fiberglass & epoxied the wing center to hold the wing on with thru sticks and rubber bands, i didnt trust the little button holding the wing on
guess i shoulda went for a lower kv , heavier motor for the 9-10" prop - tail heavy anyway- heavy motor wont hurt nothing- maybe ill get it someday
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Old 03-16-2011, 05:16 PM
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For a 9" prop, a 70g Suppo A2217-7T might do the trick. For more than 250W you might have to go up to a 2814.
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