Our brushless motor vendor called the other day to offer a stronger/faster motor for the DS160BLHV. Thing is, outputting 160oz-in and transiting 0.06sec/60° means we're near the point of diminishing returns for the class of models using this size servo. E.g. fixed-wing 3D electric models from the likes of Extreme Flight, AJ Models, and PAU.
Then I got to eyeballing the specs and realized, he was right to call me. The motor specs are intriguing because depending on the gearing, I can use it to make about 210oz-in at 0.10sec/60° - or go for more torque, maybe 235oz-in but at lethargic 0.13sec/60° - or - I can go for speed, instead.
FYI, the basic trade off when dealing with motors and gear ratios is they're always a compromise. You either go for a lot of strength vs. speed, or speed, at the expense of torque. You can't get both unless you compromise. Thing is, as I've mentioned, i really think we're at the point where for a 60" mode a lot more torque doesn't matter. Especially pretty much all pilots can feel the difference a faster servo makes in maneuvers, while extra power is only useful in a few maneuvers, which only a few pilots can pull off. The rest of the time - it's speed that floats the boat of not just the ones gifted by God with superior reflexes and skill but everyday good pilots XA pilots.
Anyway, the new motor gave us a bit more torque (175oz-in from 160oz-in) but the real difference maker is in the gear ratio we could use. This new servo is faaaaast so it's clocking a blistering 0.051sec/60°. The point being, if your high performance 3D/XA model requires loads of torque - and - you relish enough speed to make control surfaces flip like a pinball paddle within a compact mini-class package, then we're not making a big secret of what's involved.
Note; competing servos like an MKS HV9767 offer you aluminum cases but with coreless motors. We figure if you're on a budget, then our DS160CLHV is a better choice in a mini with a coreless motor because it's stronger, faster, lighter, and cost a lot less. BUT, if you want the very best mini we know how to make, the DS175BLHV is it. And note, while once you buy it, you can disassemble it and marvel at how well we do this, you can also just eyeball the pictures because we're not hiding anything! Last thing; the label says DS160 and we had already lasered the cases when we were offered the new motor.
1. Start with the best possible brushless-motor. When commutation happens electronically (instead of mechanically), the motor runs cooler because there's no insulating build up of brush dust over time. And since electrons don't wear out, a brushless-motor lasts 5X longer than a coreless-motor.
2. Of course, if you want a stronger mini-size servo, it helps to start with a stronger motor. Like the one from our standard-size 420oz-in servo - it's called thinking outside the box! Then we gear it to be really fast, how's 175oz-in/0.051sec/60° grab you?
3. The trick to shoehorning a large-frame motor into a mini-size frame is simple. It merely involves slotting the CNC-machined case and letting the monster motor hang out a little bit (which has a benefit of added cooling). Beginning with a solid billet of 6061-T6 aircraft aluminum, the end result is more than just pretty . . . it's bullet proof.
4. Then we use 10 Allen-head machine screws to secure the assembly instead of 4 (like our competitors) because once we ran the FEA (finite element analysis) within the CAD-computer we discovered this made the transmission assembly a lot more rigid. Of course, a more rigid assembly is the key to a gear train that better withstands abuse.
5. Dual dual ball bearings? You betcha! But instead of ABEC-3 bearings, we opted to use ABEC-9 because ultra high precision bearings offer better performance. Naturally, these cost more and we mention it because we're proud of what goes in our servo (and because we noticed our competitors don't publish bearing specs).
6. In this class of servo you're right to expect metal gears, but instead of COTS (commercial off the shelf) gears featuring brass/steel (plus fake titanium), we opted for pricey but much tougher custom steel/steel gears (with anodized aluminum 25T output shaft). Plus, our gears are wider (thicker) than usual because increasing the surface area means greatly increasing wear characteristics.
7. Optimized for high voltage (HV) battery packs because higher voltage means lower current (rated at 7.4V nominal, 8.4V max - but specs given at a realistic 7.4V instead of a voltage you'll only see when the pack is fresh off charge). As experienced modelers know, this becomes especially important when using servo extensions. Plus, a 2S LiPo pack weighs much less than an equivalent capacity NiCd, LiFe, or NiMH pack.
8. Since centering is the sine qua non for a high performance servo, we use MIL-SPEC components. Along with a genuine Nobel potentiometer, this means the best possible performance because we don't compromise in our goal of building the best mini-size servo money can buy.
9. If you believe protecting the electronics against vibration is important then you'll be happy to learn how instead of a cheapo piece of foam we protect the electronic components of the PCB (printed circuit board) against vibration with potting compound. This is exactly how the military and NASA bullet proof their electronics. And quite honestly, it's a pain in the hind quarters, but we think of it as going the extra mile because like you, we're modelers too. Or put another way, we fly what we sell.
Bottom line? The ProModeler Brushless SuperMini is the one you want because it's better. It's super precise, centers superbly, and is simply stronger than competing minis. This makes it ideal for cyclic duty on 500-class helicopters like a Goblin. Plus, it's compact enough for the slim wing of a super fast jet. Plus, it's über strong for 60" class freestyle electric acrobat. We don't hide what we put into it and we welcome comparison to any other mini-size servo on the planet Earth. Granted, others may offer you a similar looking mini, but for your money you'll get a less expensive motor, inferior gears, an assembly with fewer screws, cheaper bearings, and and they'll leave out little touches like the potting compound. Is it pricey? Yup! But as usual, you get what you pay for.