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lrk inrunner built from hard-disk stator

The principle remains the same, lrk, more torque per Ampere (Kt) at a lower rpm per volt (Kv). The stator is wrapped in kevlar/aramide to prevent the magnets from starting a solo career 😉 (with some nasty noises). For description, measurements, more and larger pictures:
www.cenara.com/users/ce00359/LRK220.htm

lrk- and cd-rom discussiongroup:
www.yahoogroups.com/group/lrk-torquemax/
or, if you prefer, it’s French counterpart:
www.yahoogroups.com/group/moteur-perso/

Ron, are you sure ? LRK - is a Large Rotating Can…When you told about in-runner is not tru LRK 😆

Hi Lazy, the lrk-motors, as described in the German Elektro Model Magazine articles, indeed have a rotating can. The essential lrk features are

Shorter, distributed E-shaped magnetic circuits (simulation pictures), giving more flux (for a given amount of steel) and thus more torque. Plettenberg’s Freestyle inrunner motors also use the lrk winding diagram.
the winding of half the teeth (1,3,5,7,9,11), leaving the other six teeth (2,4,6,8,10,12) empty.
coils are actived at the moment that the force in the airgap is at it’s biggest, thus increasing torque even more.

The above applies to Christian Johansson’s inrunners so one could argue that they are lrk type motors. A rotating can gives more torque by itself (whether lrk or not, for instance in a cd-rom motor) because the airgap (where the magnetic force is exerted) is moved further away from the shaft. And since torque equals force times radius…Now, to confuse matters even more 😃, there’s also the distributed lrk-winding type, all teeth have a coil. www.flyware.de uses it in their motors.

The acronym LRK stands for L ucas, R etzbach and K uhfuss, the team that published the original design in EM Magazine. Christian Lucas designs e-motors for busses and armoured vehicles ( www.magnet-motor.de ) and also did/does some work for Lehner RC motors ( www.lehner-motoren.de ). Lucas Retzbach is/was a Elektro Modell Magazine editor, Emile Kuhfuss the lathe wizzard.

You’ll find English translations of the original Elektro Modell Magazine articles at the bottom of this page:
www.torcman.de/peterslrk/index_eng.html

Yes, Ron, I know, but…
All other modification of original design name LRK ? May be we precise - what we want to build ? Modification of CD-ROM motors with mininum changes ? Or use CR-ROM windings and armature to build completely new motors ?

That’s up to you. CD-ROM motors for indoor- and park-flyers, lrk style motors from 100Watt up, as a rough guideline.

Oh thanks Ron, I use AXI line outrunners. Simple not have enought time to play with CD-ROM’s 😆
And agree with you - it’s a own decision. Basically topic are OK, but not for me.