Tuesday, August 5, 2014

Blade 200 SRX Review

The Blade 200 SRX

Blade finally came out with a helicopter featuring their SAFE technology. The results are impressive, though not as good as one could hope.

The Blade 200 SRX is a 200 size fixed pitch, single rotor helicopter. It features their six-axis (three gyros and three accelerometers) stabilization system known as SAFE. Like the 200 QX before it, it includes two flight modes with limited envelope and automatic self-leveling, and one flight mode with an unrestricted flight envelope and no self-leveling. In addition, it has added a Panic switch, that automatically switches to the most restricted flight envelope, self-levels and kills any cyclic input.

Early issues

I've had this one for longer than most before a review, because - well, there were issues.

Uncharacteristic support from Horizon Hobby

The first issue was with the first one I ordered. It would not self-level in intermediate mode. To verify this, I took the main rotor off, and spun it up on the floor.

In beginner mode, feed it some cyclic, let go of the stick, and the swash plate goes back to level.

In agility mode, feed it some cyclic, let go of the stick, and the swash plate stays put.

Intermediate mode behaved the same as agility mode. I put a number of batteries through it while investigating this, checking every possible source of problems. I eventually switched to a supported, non-programmable Spektrum transmitter (the DX5E) to make sure the problem wasn't in my transmitter.

I called Horizon Hobby about this, and they claimed it was behaving the way it was supposed to. I checked their announcement of the helicopter, the documentation, the introductory videos, and with other owners. They all say it should self-level in intermediate mode. Call HH support again, get the same story. Again.

So I returned it to the store and bought a second one. It behaved as expected.

Gain settings

I made a mistake with the second one. I checked the gain settings, and reset them all to the default values before flying it. This caused the heli to have a really, really nasty wobble with small cyclic inputs - just correcting for wind drift in a hover.

This problem pretty much vanished after I reset the various gains to the values that it came out of the box with. This took a few more batteries to get sorted, though.

So, a warning: don't reset the gain settings it comes with until after you've flown it!

Some tail drift

Finally, the tail had some wag and a little drift. Nothing really bad, but - well, I was expecting better. I upped the tail gain to correct the drift, and the wag got bad enough to make me nervous. I put that back, and have been flying that way. There's one more thing to try, but it's fun to fly as is, and I haven't felt like mucking with it more since.

Flight characteristics

As mentioned, it currently has a little bit of tail drift and wag. Neither is a problem in flight. The wag is mostly visual, and only when moving around. The drift is trivially corrected, and actually lower than some other heli's without the SAFE software.

The downside of SAFE is that I can't trim out the tail drift. Well, I can, but it will re-appear after I power cycle the heli, because the software compensates for the non-zero input.

The other nasty flight characteristic is that, compared to most 'copters, it just seems under powered. Half stick is just barely a hover when you're in ground effect. This sometimes causes issues when doing a fast descent, as it doesn't pull out of them nearly as quickly as I'm used to, leaving me bumping the ground a bit harder than I'd like. The most popular fix seems to be changing the pinion gear to get a higher head speed.

Other than that, it's a very pleasant flight. Earlier reviewers have called it "the quadcopter pilots helicopter." I don't know if I'd go that far. Where the self-level modes in a six-axis quad causes a fairly obvious slow down and stop when you zero the cyclics, this doesn't. It keeps most of it's forward (or sideways, or backwards) momentum after it levels. This is only a problem if you're expecting something different.

In agility mode, it won't self-level. But you do get enough flight envelope to do basic aerobatic maneuvers, just like the 200 QX. In theory, the Panic switch is supposed to give you enough confidence to stretch your limits here, but the lack of lift and not stopping after leveling sort of kills that for me.

Bottom line - this heli isn't as easy to fly as a coax or a quad. However, it's not nearly as hard to fly as most fixed pitch helis, and the agility mode makes it fly a lot like a collective pitch heli. It is a lot of fun to fly, and provides a better step between coax and collective pitch than was previously available.

Design issues

Outside of the flight characteristics, there are a couple of things Blade did that I think they could have done better.

Still no switch

Like it's homonumeric sibling, the 200 QX, there is no switch for the battery. Given that it has a typical helicopter canopy mount - tuck it in the front, and poles through grommets to hold the back in place - this makes it a real pain to plug in the battery and get it level with the canopy on before the flight control board initializes. I've finally given up on getting the canopy on before it initializes. I now plug in the battery, set it down, wait for it to initialize, then put the canopy on.

No LEDs

Well, almost none. The receiver and ESC both have an LED, but they don't do anything during flight.

In particular, there is no indication of which of the three flight modes you are in! This makes checking the setup on a programmable Tx nearly impossible. Most helicopters don't have such an indicator, but they also don't have as radical a change in behavior as stability to agility mode.

No LVC

Worse yet, lack of LEDs means there is no indication that your battery is running out. Other than, of course, the already under-powered heli losing power.

Sure, a good transmitter will have a timer, and will even let you pause the clock when the throttle is off, or possibly even change the clock rate with the amount of throttle. But still - that's just a guess. Changing batteries will change the time. A problem with the battery or charger could drastically change the time. And so on.

To add insult to injury, they put a telemetry-capable receiver in the helicopter. But it's use is restricted to reporting various gains and a vibration measurement. The absolute best battery voltage tool would be to use that telemetry to send battery information back to the transmitter. Just sending back the voltage allows for a voltage level warning in your hands instead of on the helicopter, which is a major improvement. Given other information, some really nice things are possible. But we get none of that.

Hence, my first modification to the helicopter: zip-tieing a lipo alarm to the tail boom. Still flies fine, but now I get an alarm when the battery voltage gets low. I've ordered a smaller alarm to dedicate to this.

Summary

While I seem to have spent a lot of text on problems, the biggest one to me is Horizon Hobby's support issues. The others are either minor, or trivial to fix, if not both. None would prevent me from recommending this as a second helicopter.

Being lied to by the support staff about this helicopter makes me nervous. Blade helicopters tend to be costly compared to some of the clones on the market, but Horizon support is usually outstanding, more than justifying the extra cost. If that's changed, it may be time to re-evaluate buying from them.