Searching for the best match.........

Monday, January 9, 2012

AS3X vs Z83X

Update:  Scoring matrix added, below.

Update: Z83X vs. AS3X flight testing is complete.  Flight videos and conclusions listed below.  Maneuver by maneuver comparison chart to follow, here soon.

AS3X is a welcome and very interesting new ultra micro tack-on from Horizon Hobby.  It brings an affordable small 3-axis gyro to a class of models that can certainly benefit from more stability now and then. But at around $200 sale price for their first entry level BNF UMX Beast 3D, or roughly double the price of the previous version, it racks up quite an opportunity cost. 

Same price, including 3-axis gyro systems 
and shipping.  Head-2-head results soon
While I'm sure it is true that some buyers of UMs actually want a high end microscopic plane (myself occasionally included) I think most UM buyers are simply looking for value. A few recent trips to the LHS indicate that most UMs on the shelves these days--competition has really skyrocketed recently--are not the pricey Horizon Hobby mini's, but less expensive competing RTFs like the new and excellent quality $59-$89 Ares series, at least in terms of number of units sold:
Make no mistake about it, these are some incredibly clever micro models and they fly extremely well (reviews forthcoming).  They too represent a heightened value proposition, but instead of targeting experts they aim to appeal to the entry level value buyer.

For example, the Ares Trainer 100 RTF ups the value proposition with a full foam airfoil flies that like a larger plane and 20 minute flight times at under $90 retail, radio included.  The swift and sweet-flying MD-500D RTF coax is USB chargeable with a catchy hardened scale body and a steel main shaft.  And the unique 2-channel Nano-Micro indoor RTF airplane is about half the weight of a Parkzone Vapor and flies in record small spaces.  It is the lowest priced, value-conscious RTF airplane in Hobbytown.  All of these models attempt to raise the value bar.

Barnstorming on to the scene with quick acceptance, the clearing of the Ares shelf tells me that most Ultra Micro buyers are really value-oriented, not size oriented.  With that in mind, one has to question the long term viability of gold plated 3-axis gyro micros.  Sure, there are always high end buyers looking for performance, but will there be enough performance enthusiasts in today's economy willing to buy a UM novelty when a full size model can be had for the same or less money?

Enter "Z83X," which could be any inexpensive 3-axis gyro system coupled to the model of your choosing.

In a value-driven market, I want to know how hard it is to match AS3X. Horizon claims AS3X has been years in development and is expertly tuned, but when I compared their brand new 3-gyro mini Pitts M12 to a Cessna 150, of all things, with two gyros slapped on last minute, the Cessna was significantly more capable handling wind and high alpha hovers.

That got me wondering what gyro-stabilized system an average enthusiast might be able to throw together after a few minutes of planning, and how it would stack up to Horizon's off-the-charts AS3X bragadocity.  In the rest of this post, I'm going to take my first shot at beating AS3X in a value + capability showdown.  I have no idea how it might turn out, but if my hovering Cessna is any indicator, it should be worth the effort.

Product description Price Weight

GWPG03J - GWS PG-03 Piezo Gyro/JR $66.84 219

AT-Pitts - Hobby King Pitts Special Plug-n-Fly (4 A..
$74.99 3190

T1800.2S.30 - Turnigy 1800mAh 2S 30C Lipo Pack $10.95 163

Turnigy-3S - Turnigy balancer & Charger 2S-3S
$4.49 99
Total: $157.27 3671g
Air Parcel (UNITED STATES) 3500g - 3999g  $46.94 
Your Total including shipping $204.27

Compare to the exact same trim level, below.  Granted, some will have a UMX 2S charger or battery already, but the same can be said to a higher degree with deal above it so I decided to match the contents of the box, exactly:

UMX Beast 3D BNF Basic with AS3X Technology  Price: $139.99 
200mAh 2S 7.4V 25C Li-Po, 26AWG  Price: $23.99 
Celectra 2S 7.4V DC Li-Po Charger  Price $29.99 
DC Power Cord: UMX Beast  Price: $4.99 
5x2.75 Electric Propeller: UMX Beast, Sbach 342  Price: $3.99 
Spinner: UMX Beast 3D  Price: $3.99 
Total Before Tax and Shipping $206.94
Qualified for free shipping

By design, the two stabilized airplanes cost about the same shipped to your front door.  I decided to install a Hitec Rx for built-in telemetry, a Spektrum compatible Rx only adds $8 to the model cost with the same reliability as a Spektrum-branded Rx. Since I didn't elect to buy one, that $8 isn't totaled in the shopping cart, above. I bought another prop and spinner with for the UMX Beast since the AT Pitts Special comes standard with two props, and the Beast spinner is disposable.

Although the trim levels are identical, it is worth pointing out the the Z8X3 system is transferable from aircraft to aircraft, as is the ESC, motor, etc, so some substantial part of the value delivered  is uncaptured by the simple metric of price.  Also worth noting, the Beast 3D is currently on sale, the regular price is listed $40 higher.


My Z83X triple axis gryo system Art-Tech Pitts S2B is here and complete.  The price including a battery and a charger came in insignificantly cheaper than the UMX Beast 3D.  I didn't actually have to buy new batts and a charger since Art-Tech uses industry standard accessories, instead of forcing the buyer to buy all-new support equipment for their airplanes.
There aren't many silhouettes that can make the 
Beast 3D Pitts Model 12 lines look awkward.  
The Hobby King paint scheme is not my favorite on
the Art-Tech Pitts, but it's hard to complain for $75.
"English-as-a-second language" doesn't adequately
describe the Chinese manufacturer, who depicted the word
"Pitts" in mirror-writing on one side of the vertical stab. 
As a former Z8RC favorite, I already know the 21 oz (including Z83X), 34" wingspan Pitts bipe flies beautifully with a Wing Cube Loading of just 5.  But this one is a little different.  It features ground breaking, world revolutionizing, Universe-altering Z83X, a specially tuned, tailored and customized 3-axis gyro system, so advanced, it makes any model fly like an expertly tuned double-scale model--it feels even bigger and better than the original, full size aircraft.  
Ultra-spectacular, mind-blowing, breathtaking new 
and exciting technology.  This ground-breaking Z8RC system 
is even portable from aircraft to aircraft, but that requires 
almost 3 minutes of custom tuning and a recalibration of Z83X 
to enhance unique flight characteristics. The third gyro resides 
in the center of the fuselage to maximize responsiveness!!!!!
I spent in excess of 3 minutes developing, installing, and painstakingly tuning Z83X specifically for the Pitts S2B, carefully turning six, count 'em, six adjustment screws to fine tune over a zillion control surface corrections per microsecond.  This mind-blowing advance brings breathtaking new and exciting RC technology within reach of the average flier, making every other RC system on the planet obsolete.  Errr, uhm, well, at least that's what E-flite seems to think...

Horizon Hobby hype mimicking aside, I added three $22 off-the-shelf GWS gyros to the $75 Pitts Special.  Each weighs 7 grams, or 4 grams with the case removed according to GWS.  So Z83X could install in as little as 0.4 oz.  Hobby King had $11 gyros which claim exact equivalence to several hundred dollar Futaba systems, but I've used these gyros before and I know they are excellent performers, so I went the "expensive" route.  Total cost for Z83X: about $67. 

Installation is as simple as plugging each servo into its gyro, then plugging the gyro into the receiver.  Done.

There are two adjustment screws on each servo.  One adjusts the centering, basically sub-trim.   The other increases or decreases the amount of gain, or control surface movement.  It takes about a minute per servo to customize, you can do it while they are powered up, shaking the airplane to check the gains.

The side-by-side flight comparisons are complete and the results are in.  

I'll make this quick and to the point - the Z83X airplane beat up the UMX Beast 3D rather badly.  The aerobatic domination of the S2B Pitts Special over the micro Pitts Model 12 actually surprised the heck out of me.  But this flight test reminded me why the Art-Tech Pitts Special bipe was the Z8RC all time fav for a long time standing.  

I tweaked a few things on purpose, but for the most part Z83X is a cheap, 3 minute start-to-finish, off-the-shelf 3-axis gyro solution.  One thing I tried to do was under-gain the gyros in comparison to AS3X, which I think has too much gyro-dictated flight path bending--probably to keep the lead-nose little Beast pointing skyward during hover attempts--sometimes giving the mini Beast a mind of its own.  

Since the AT S2B is inherently perfectly balanced (with a 1300 mAh 3S upfront), it doesn't really need Z83X which is exactly why Z83X was so successful in greatly stabilizing the plane in winds and during "poses," without changing the flight characteristics much, if at all.  Z83X is what AS3X wants to be, but just can't overcome the inherent design flaws of the underlying UMX Beast model.

Z83X won easily in all maneuvers except one: harriers.  The UMX Model 12 Pitts has more elevator authority to jack the nose up farther and without quite as much wing rock, but both planes exhibit a significant tendency to wing rock in stabilized, high AOA harriers.  The Z83X aileron gyro has plenty of room to gain up to help suppress the high alpha rock (maybe a future update...).  

Another Z8RC plus: the off-the-shelf gyro system is aircraft transferable and user tunable.

Particularly in healthy winds, the inherently more twitchy 2 oz UMX Beast 3D got battered.  The 21 oz Pitts S2B with Z83X was really solid.  The Z83X Pitts S2B was easily controllable, even stable, in 10-15 mph winds.  Pretty darn fun experiment.  

Vids follow.  Notes:
  • The first Z83X Pitts Special video was cut short for a mem card full error. Bummer, the landing was sweet. The Pitts S2B is an amazing plane even without Z83X, but with it, it has to be my easiest landing plane ever.
  • The Z83X Pitts S2B's ability to hover so easily really surprised me.  The only challenge is that the aileron throw is right at the 125% servo throw limit to fend off a torque roll. If you start a climb to power out of it, the plane rolls left a little from the additional torque against no more throw.  I could have dialed-in a little more throw in when I put the plane together, but I thought 4 full-wing ailerons would have enough.   I think the problem is more that the small 10x4.7 prop doesn't blow the ailerons much, so switching to a 11x3.8 prop might fix it too but could add torque to match.  Maybe in a day or two I'll iterate.  
  • The Beast 3D video was cut short by my camera's 10 min limit--it actually finished-up with a tree-catch about 10 secs after the camera quit.  A worbling hover gave up the ghost while pushing the 200 mAh batt way too far.  No scratches, yay!

I'll post a score card in a future update to better quantify how the two gyro systems compared, maneuver by maneuver.



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