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Author Topic: Brushless motors on ebay  (Read 1474 times)

explorer750

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Brushless motors on ebay
« on: October 30, 2008, 10:41:50 AM »

Hi,

I have been looking at the new griffin 600 and am intent to fit a brushless motor. The other day I found on  ebay a large selection of motors and speed controllers for really low prices ( about 8-9). Compared to paying 30 in a shop. My question is are they any good.

http://shop.ebay.co.uk/items/__brushless-motor_W0QQ_nkwZbrushlessQ20motorQQQ5ftrkparmsZ72Q253A1298Q257C39Q253A1Q257C66Q253A2Q257C65Q253A12QQ_dmptZUKQ5fToysGamesQ5fRadioControlledQ5fJNQQ_trksidZp3286Q2ec0Q2em14QQ_pgnZ1?_trksid=p3286.c0.m14
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Martin [Admin]

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Re: Brushless motors on ebay
« Reply #1 on: October 30, 2008, 11:38:38 AM »

Most of the brushless motors specs on ebay seem to be a little "exaggerated" so buy a motor 10-20% better
than what you need. Plus all normal ebay cautions apply!
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andrewh

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Re: Brushless motors on ebay
« Reply #2 on: November 10, 2008, 05:04:20 PM »

explorer

I have discovered that the Griffin is a hoovercraft - don't know what the proposize but lets guess 8 inch x 4 or 6

The ebay site your pointed to is heli - based, and all the motors I looked at are in the 4000 to 5000KV (Helis use BIG gears)

Say you ran only a 7.2 V pack this would give you 7x4000 rpm 28000 RPM at the prop which on an 8x4 is in the region of 2 KW (working from memory) and the tips would be well into the noisy sub-sonic region

These motors would be the canine pendular appendages if you were running a 4 inch prop, ducted fan impeller or waterjet, but I feel that someting in the KV1000 to 2000 range  (aircraft) range would work more reasonably

I'm making lots of guesses, and relying on my memory a lot in this answer
andrew
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explorer750

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Re: Brushless motors on ebay
« Reply #3 on: November 10, 2008, 07:35:47 PM »


Palaform suggest a 400 size brushless motor 1100rpm/v or above. If you look in Model boat November issue their is a review. The prop they use is a APC 7x5.
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