dnilsson

I'm looking to buy a new set or servos that I plan to be able to use in a couple of different size aircrafts, the first one will probably be an Quique Somenzini Yak-54 (72" version) but I'd like to be able to use the servos is larger airplanes later. So my current thinking is to invest in a set of JR DS8411s or DS8411SAs. I know that might be a little overkill for the 72" Yak but I've never seen problems due to having to good of a servo...

So now the question, how do I choose between the 8411s or the 8411SAs ? I know the SAs have a mix of nylon and metal gears where the 8411s are all metal. I also know that I can convert 8411s to 8411SAs if need be, and I assume I can convert 8411SAs back to all metal as well ?

I'm looking to get 5 of them (1 for rudder, 2 for elevator and 2 for ailerons). Should I favor metal gears for some applications ? All metal ? Or all mixed gears ? Any thoughts welcome...

Chris Moon

My Feedback: (8)

The 8411sa will wear better than the metal gear version. I had some 8411's and converted them all to 8411sa. Some have hundreds of flights in my 2 meter pattern plane and I cannot detect any noticable gear slop or wear. You can just get the regular 8411 and the conversion gears, then just run the metal gears until you get some slop and then convert to the SA version. BTW, I have a Qui Que Yak and it is a great ARF and flies very well.

dnilsson

Thanks for the tip, that sounds like a great idea. I noticed that the metal gear version (DS8411) is about $15 for expensive then the DS8411SAs ($115 vs. $100). Would you still think it makes sense to get the 8411s first ? I mean, if the SAa perform as well I could save the $75 extra that I would spend on the 8411s when I'm buying 5 of them... The conversion set is about $9 though, so that's not that bad...

Glad to hear you like the Yak, I was planning on a YZ140 Sport engine. Seems like most people recommend this engine.

Thanks
Daniel

mr_matt

My Feedback: (10)

I converted all of my 8411 to SA, but you might want to check with JR about your particular application. I think the SA was meant for helicopters (I could be wrong) and the gear strength is less, so shock loads might be bad for it (I mean like handling or bumping those big surfaces on a 3D plane).

I use the 8411SA on fast jets but my surfaces are balanced so a hard landing will likely not strip the gears. I think in the air they would be fine, just ask JR to be sure.

In any case the slop is much less with the 8411 SA

dnilsson

Matt,

Sounds reasonable, I'll probably give Horizon Hobby a call before I make the decision.

On a related topic, I was planning to use 2x800mAh or 2x1100mAh NiCD batteries. The 2x is to create some redundancy in case of one battery having a short or one cell dying. I know it's not as good astwo independant systems but it's better then a single battery feeding a single receiver.

Using 5 DS8411 servos on a plane like the 72" Yak-54, should I plan for a total of 2200mAh or should 1600mAh be enough ? I usually don't charge the plane at the field, and I'd like to be able to be able to get 4-5 flights per visit to the field without worrying about power. I do check the voltage under load though before each flight.