Anyone have experience with Key Fulcrum servos?

[Clifffff]

The title says it pretty much. If you have any experience or have a friend or a friend of a friend who has any experience with Key Fulcrum servos, please drop a line here.

Thanks in advance!

 

[guinnessdublin]

Sorry have not seen them my side of the pond, what’s the spec of them?

 

[Clifffff]

K7865 claims 75 kg-cm @ 8.4 V inside 0.100 sec/60° MRSP €110
K8871 claims 75 kg-cm @ 8.4 V within 0.080 sec/60° MRSP €140

They claim to use 4 pole BL motors.

However, AGFRC which is a reputable brand also makes servos with 4 pole BL motors running at 8.4 V and delivering similar torque levels but slightly slower (say 0.125 sec/60°). They charge anywhere from €200 to €280...

 

[guinnessdublin]

With a 6v battery hump will be weaker & slower of course!

 

[Clifffff]

I abandoned the cursed 6v battery humb long time ago. Even in my Savage Nitro, I have a mini 3s LiPo pack connected to a step-down module delivering exactly 8.4 V to the steering servo and the acceleration/brake servo, up to 15 A. Then there is a second step-down module which feeds off the 8.4 V supply to provide 6 V constant to the R334 Futaba receiver.

You always need a voltage regulator. Connecting a say 2s battery pack directly to servos could lead to the battery pack emptying an 11 V spike for long enough to completely fry your servo. Battery discharge and linearity can hardly ever be reconciled.