Tuesday, December 25, 2018

Awesome Servo Testing__ProModeler DS100DLHV



With at least two new 52" 3DHS planes coming in 2019, now's a good time to invest in the class. While these are still medium sized planes, they are very, very serious performers. While the Xpwr power system ands Xcessories are perfect for these planes, the servo argument never ends as people try to find that elusive gold plated wunder servo. 

Only this time we may have actually found it.

ProModeler's new DS100DLHV is on the leading edge of this class. It was designed specifically to fit in the Extreme Flight 52" series and outperform other manufacturer's offerings. The servo drops right in with no fuss and delivers outstanding performance, durability and reliability. This is a brand new servo that was made especially for these planes.

I'm not going to get into specifications too much. That's not what we do, but you can check the site for all the numbers if you're into that. Good specs are nice and all, but more important is what the plane is telling me, which we will get into later. To me, flying is more important than specs. However, most important spec on this servo is the staggering 100 ounces of torque. This is nearly double what have been getting. No one is going to be stalling or blowing back these servos. As a result, the servo is also (comparatively) under stressed, which always goes a long way toward assuring reliability and durability.

First, a quick look at the outside shows this is a quality piece. After you have done this hobby for awhile you can spot a quality product just by looking at it, and this is it. What interests me is what I have read and seen in pictures about the servo's design and construction. This is a serious servo that's designed to last.



You can see above the use of six bolts to secure and align the case top. This gives more precise alignment and increases torsional rigidity to assure perfect gear train alignment under all stresses, though that machined aluminum case already looks pretty darn rigid.

Most of the problems we face with these smaller servos are with the gear train getting sloppy. This leads poor overall performance, especially centering. Poor centering leads to a poor flying plane.

Nothing is more infuriating than chasing your trims all day. A nice, solid, smooth gear mesh that stays that way makes for a perfectly trimmed plane, which is why we are all looking for that perfect servo anyway, right?

Promodeler addresses this with higher quality materials and tighter tolerances. You will also notice the entire gear train is all metal with no sacrificial plastic gear.




Especially telling is how the gear pins secure in the case top. Most servos have their pins secure in plastic that can wear and even outright break, cause the servo gears to come out of alignment and center poorly (at best) or just outright lock the servo up (definitely worst).

Promodeler inserts brass bushings into the case top to secure the pins, so they will stay in perfect alignment after a lot of use, or even hard usage.  Also noteworthy here is how the output bearing is pressed into and aligned in the case top. Good alignment minimizes friction and makes for a smooth running servo. 


I can tell from the smooth gear mesh that they will be extremely long lasting.. I do not expect them to get loose or sloppy. This assures good centering, which to me is possibly the servo's most important attribute.

I'm not a tech guy and this isn't a tech blog, so that's as teched out as we are going to get. I did, however, want you to see the insides of the servo and how well they are built. As a result of this quality design, engineering, material and construction coming together, you get a super powerful, smooth running, long lasting product.

I highly recommend reading ProModeler's John Beech excellent article on how ProModeler servos are engineered and manufactured with special insight into the DS100. That can tell you a lot more about the servo than I can, and it was enough to convince me these were worth a try. I also now know a lot more about servos in general than I ever have.

FLYING



There has been a lot of hype surrounding ProModeler lately, and after reading about the servos and studying the photos of the internals, I was expecting a lot. I got an appreciation of the servo's quality installing them, running them, and setting up the control surfaces. The centering caught my attention right away, maybe because that was the improvement I was looking for most, but also because these are the best centering servos by far that I have ever seen. By far, and while this stood out on the bench, the difference this makes in the air is pretty stark.

So, you can see I went in with high expectations, even though I was trying to temper that a little. You never want to get caught up in the hype, but then again, this time it was impossible because just working with the servos and setting them up went so smoothly, and of course the servos run so smoothly that I was already pretty happy. Seeing the quality on the inside of the servo from pictures, and sampling the quality on the outside working with them, it was hard not to be convinced even before I flew them, but remember, flying is the only part that counts.





After a quick trim pass I turned the plane around and immediately felt the difference when I let go of the stick. The plane stayed exactly where I put it as I stood there watching it fly completely across the field in a dead straight line. Immaculate centering, and we weren't just lucky either. After repeated turns, snaps, and spins in both directions, the plane always came out exactly were I put it and stayed there, kind of like an airplane is supposed to do.

You trim it and forget it, and after a full eight flights (so far), I still have not touched my initial trim settings. The plane has also gone where I pointed it and stayed where I put it every single time. ProModeler servos undergo a one million cycle test during development testing, and I have no trouble believing these servos will center like a vice for at least that long. After repeated rolls, snaps, spin, etc, nothing could shake off the trim lock these servos provide. Zero trim shift a full eight flights in as compared to some servos that drift back and forth every pass across the field.

This...... right here.......Takes us to the next level.

Now, you don't fight the plane. Now you can concentrate 100% on flying the plane, and completely forget about the trims. Forget about the set up. Forget about everything except you and the plane and the sky, which is what all of this is supposed to be about anyway. I can't even begin to explain how important this behavior is in instilling confidence in the pilot, and taking a huge work load off him. When the servos center properly the plane stays trimmed. The pilot can relax and let the plane do the work. You don't have to fight the plane every inch of the way, or put up with it fighting you. You point it where you want it to go, relax, and then tell it what to do when it gets there.

Point, shoot, relax, repeat. Special focus on the relax part. Yesterday was some of the easiest flying I have ever done, all while pushing the plane hard as hell.

Just in centering alone it was a milestone day for me. With the plane flying so much more precisely, I was able to fly it more precisely instead of making corrections all the time. You can see in the videos my flying gets better and better as I become more and more confident the plane is going to go into a maneuver the way I want it, and come our where I want it, and stay where I put it. The plane is infinitely easier to fly like this.

So, we could stop right now and fully justify, and more, switching to these servos, but there's even more. I do want to point at that at this point, even without considering the other attributes, I was still satisfied.

When it comes to torque, now we have double of what we are used to using. Even that was sufficient, but now there's a new zing to snaps and tumbles. At the moment, while waiting on a longer servo arm, I am running less than my usual amount of elevator throw, but the response is so fast and strong that I may not change it. It's working so leave it alone! The Extra is such a benign plane that it is not the ideal plane to demonstrate walls and parachutes with, but there are several of those in all the video and you can see for yourself those come off with absolutely no stalling or blowback. Nothing. Again, we are dealing with double the torque that we are used to. A fast servo doesn't help unless you have the torque to push that control surface against the elements, and this servo excels here. Double torque.

The faster speed caught me out a little. Initially the plane felt jumpy, but that was just the instant response. It is so much faster than what I am used to that I was over controlling the plane on entry to maneuvers, and it looked like someone who was either not very good, or had too much control in the plane. By the end of the first day I had adapted to that and it wasn't so bad, but this was something I had to get a grip on.

Overnight I had a bit of a rethink and as usual, setup is everything and that's where the answer was. I have been dialing my expo back since I started flying electronic stability systems, so I had room to put some back in. I put 10% more back and the next day all trace of the problem completely disappeared. Now I can put the servo's smoothness more to work, and you'll see that in the next set of videos which we hope to have soon.



Intangibles, And The Nail
So, we have checked all the boxes with a score of excellent. The quality of engineering and construction was never in question. It was just a matter of how they did in the air that was left to be tested. Torque is more than we actually need, but nice to have, and speed was more than I could deal with until I tamed it with a little expo. So far the servo is outperforming the pilot, and I'm sure they will probably outlive me too.

The only thing I have not had the time to test is the durability, but at this point I have no doubts. I've seen the insides and I've seen them in action. I've felt the difference they make. This was like test driving a Porsche. After half a lap around the block you didn't even need to drive it hard and you just knew you had your hands on a bad ass quality hot rod. These servos are bad ass quality hot rods.


The final piece is the intangible, and those are almost impossible to put into words. It's the feeling you get, and with these, the simplest way to explain it is that the plane feels magical. Again, it goes and stays where you put it, and it does that every single time. Essentially, you have absolute control of the plane like never before. These have always been nice planes, but now with these servos the plane responds so much better and so much more precisely that it goes from really nice plane to deadly serious 3DXA weapon.

This showed up in how much more precisely I was able to line the plane up for maneuvers, and how close I could cut my margins. I used to need more margin because the plane was never super fine trimmed and centering perfectly, but now that it is, if I put it somewhere, that's where it goes. I never have to make corrections on my entry because the plane is always flying straight, and this makes the maneuver, and especially the exit straight, like it's supposed to look.

The most telling comments came from my friends who were gobsmacked with how much better I was flying just overnight. I'de like to claim I'm flying better, but to be real, it's the plane that's flying better, much, that is. The most common comment was something like "that thing is locked in. What the heck did you do to get it like that?" The plane was flying so much better it allowed me to excel with it instead of fighting it. The higher performance makes the plane easier to fly and easier to look good with.

My final observation after flying yesterday is probably the one thing we should take away from all this. I have never felt more connected to a plane, and have never been able to extract as much performance as I can now, and it's all down to this simple change.

I knew what faster servos would feel like. I knew how more torque would play out. I knew what a colossal improvement laser like centering would make. What caught me by surprise is just how much difference it would make when added together, and how much better the plane would fly, and allow me to fly.
Nail: EPIC

Set Up

Changing to a different brand of servo and using different servo arms could have been a major adjustment requiring a lot of guessing, missing, and tinkering, but this was a breeze. Promodeler's excellent PDRS101 polymer 1" servo arms are essentially identical to the Hitec arms I have been using, only they offer an additional hole's worth of throw. You can spend a lot of money on arms, or you can use these which aren't as snazzy, but they get the job done that way it's supposed to get done. No fuss. They just work.

Ailerons
No drama here. This plane had previously flown with HS85MG servos, so all that was required was drilling the servo holes and changing out the servo arm. Here notice that I used the second hole from the outside. This gives you about 31-33 degrees of throw, which is what I like on these planes. If you need more throw, there's another hole available.



Rudder
Again with the 1" arm and using the second hole, I have nearly perfect thrown both directions. I wish there was more to add, but it's just simple and it works. It doesn't make thrilling reporting, but it does make for easy and reliable set up, which is more important.


Elevator
Here I used the 1" arm and the outer hole. Usually use an Xcessories 1.25" arm to get 88 degrees of throw, but I did not have any in the required 25 tooth spline. I can order that next week, but for now with the 1" ProModeler arm and my end points cranked, I can get about 70 degrees, which for most people is well more than enough.




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