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Wednesday, August 29, 2012

Hobby King Deamon-2000 – Build and Flight Review


“Demon” (spelling corrected) describes the personality of this high performance glider perfectly.

- Wingspan: 79”
- Length: 42”
- Flying Weight: 28 oz (RTF minus battery)
- Wing Cube Loading: 4.5

- Fiberglass fuselage
- Balsa and plywood wings and V tail
- Push rods with casings installed
- Hardware

- Motor: 2845 1800 kV
- ESC: 40A
- Prop: 10x6, folding
- Spinner: 30mm with folding blade hub
- Servos: 9-15g metal gear

- 2855 2100 KV Brushless Inrunner Motor: $13
- 4x Digital Metal Gear Servos: $28
- 50A ESC w/3A Switching UBEC: $11
- 30mm Aluminum Spinner, hub & 10x6 blades: $12
- Model: $120.86 including USA warehouse shipping
= $185 to front door

- Upgrades linked in price list, above

ON THE GROUND                                                                   



The ARF arrived very well packed and undamaged.


As we’ve come to expect, the wings and V tail were beautifully constructed and covered.  So much better than I could do with a kit build.

The carbon fiber canopy is gorgeous and tough as nails.  It is designed to roll up a bit when uninstalled, then unroll to squeeze the fuselage when installed.   I added two CF braces on the underside so it keeps its shape even when uninstalled.


The V tail halves simply get glued in place, I stripped the covering off the portions of balsa at the glue points.

The wing halves slide over an included carbon rod, then get bolted on at the rear of the wing root.  There are strings embedded in the wing halves to help thread the aileron servo wiring.

This only difficult part of the build was getting the wing halves to slide over the supplied carbon rod, it is a very tight fit.  I had to lightly sand, spray with Teflon, then crank the rod in like a screw.  The second wing was a lot easier to waggle on the rod protruding from the first wing half. 

I can transport an 80” span model without disassembly, but the tight wing rod could present a convenience problem for those without 80”  of cargo room. 

I elected to glue the wing and rod up as a single piece, for strength. 

I decided to make this glider a screamer, so I installed a 900W 2855 2100 EDF brushless inrunner motor and a 50A ESC.  The manual calls for a 2845 1800 KV inrunner and 40A.

Here are the measured static specs of my complete setup, including a 3S 1800 mAh battery (20-30 min flight time):

RTF Weight Amps Watts Static Thrust T:W
RPM Pitch Speed
35 oz 49 585 74 oz 2.11 22,000 125 mph



- The carbon wing rod is a very tight fit.

IN THE AIR                                                                              


Shocking speed and power.


Rips itself out of your hand at full power and climbs to limits of eyesight (estimated 600-800 feet) in less than 10 seconds.


Plenty of throw on high rates for extremely energetic slope soaring, but not with excessive authority.

No dihedral equals neutral stability in the roll axis.  Still, easy to fly precisely due to the large wing.

Powered climbs are so strong and so brief that a large percentage of the overall flight time can be unpowered. 

High speed passes become drag limited at approximately 100 mph.  Sound effects feature a smooth inrunner whistle on top of the more violent tear of a balsa drum.  Awesome.

Glide ratio and hang time appear to be excellent, but more testing is required as the maiden was very windy and turbulent.


Loops can be tight (20 feet) or huge (100s of feet) with solid pitch authority giving way to mush when approaching the stall. 

Roll authority is the most limited, even on full rates (set up as 120% aileron up throw, 50% aileron down throw), 360 degree rolls were less than spirited.  Adding some rudder (V tail – much like ailerons) helps snap the roll.

Yaw authority seemed a little mushy, but strong turbulence made it hard to assess.

Landing was a pure vertical drop in today’s 20G30 mph winds.

Oddly, even after my power system upgrades, CG/balance still seemed on the rearward limit of just about perfect.


OMG thrust and speed are strong. 

Full power uses a lot of battery, but several hundred foot climbs are so brief at 100 mph in the vertical (150 ft/sec) that it doesn’t impact flight time that much:

1. Pedal down
2. Nose up
3. Hold for 5 seconds
4. Chop to idle
5. Glide for a few minutes
6. Repeat
7. Repeat
8. Repeat
9. Repeat
10. Repeat
11. Repeat
12. Repeat
13. Repeat
14. Repeat
15. Repeat (You get the idea…)

Cruising at low throttle settings still results in serious pace and barely sips the battery.  Real time telemetry showed 11.6 volts and holding steady with 50% throttle, about 10 minutes into the flight while zipping the big Demon along with a faint whistle.

A lighter setup might be even more fun as for sailplane/slope soaring purists. 

My setup is on the heavy side for a sailplane:

Gliders - 1 to 5 (Deamon WCL = 4.5, setup for speed)
Trainers - 5 to 8
Aerobatic - 8 to 11
Scale - 11 to 15
Racers - 15 and over


Full up-spoilerons mixed with 12% down elevator mapped to the Aurora 9’s Left Slider were very effective.  In todays strong winds, the sailplane descended slowly on a straight down down-elevator’s 90 degree glidepath, with the nose level on the horizon all the way through touchdown.  Under complete control.


- Sluggish aileron authority at slow speeds


Runs down EDF jets with little effort and out-climbs 700-size helicopters.

Serious high performance soaring = serious fun. 


Appearance: A
High vis high contrast color scheme.  Some might take issue with the red checkered underside.  V tail profile looks mean in the air.

Aerodynamics: A-
Slippery and sleek.  No dihedral adds flying time with neutral stability.  Relaxing to fly on low rates.  Struggles in roll.

Power System: A-
Short duration, high-amp bursts followed by plenty of glide time to rest the battery.  Battery lands hot after a few 100 mph passes.

Build Quality/Durability: A 
High level craftsmanship.   As good as any balsa & ply ARF on the market.  Fiberglass beautifully done.  Luv the CF canopy.

Value:  A+
2 meter, no compromise shock jock well under $200--shipped.

Overall Grade: A+
Extreme-performance sailplane/slope soarer.   Or is it a jet?

Saturday, August 25, 2012

SkyAngel MiG-29 Ultra Micro – Build and Flight Review








ON THE GROUND                                                                   






IN THE AIR                                                                              











Appearance: +

Aerodynamics: + 

Power System: +

Build Quality/Durability: +

Value:  +

Overall Grade: +

Banana Hobby/LX Models Super F-16–Build and Flight Review


ABOVE: A typical Lead/Wingman combat config.  This pair has already dropped 4 x 2000 pound Laser Guided Bombs, as evidenced by the set of empty MAUs on each jet and the laser designating targeting pod on the leader’s right chin mount.  Targeting pods are rarely photographed in the open position—note the glass eyeball has rotated out from its normal hiding place in the stowed, protective ground position.  The leader is using it to find and track the heat signature of the Tanker taking the photo (refueling doors on the spine are open).  These two F-16’s are heading north.  You can tell because the wingman’s jet has an IR Nav pod used at night and all the MAUs on stations 3 and 7 are spent; so the sun is rising post-mission, not setting pre-mission.

BELOW: Loaded Blk 40 with 4 x AIM-120s on stations 1, 2, 8, and 9;  marking rockets and TER mounted Mk-82s/GBU-12s on station 3 and 7; external fuel tanks on stations 4 and 6; ECM pod on station 5 (centerline), with a Targeting Pod on the right chin and Nav pod on the left.  Takeoff weight: 46,000 pounds, about the same as a combat loaded World War II B-17, but with longer range, many times the speed, and few foot bombing accuracy—not to mention it is still one of the best Fighters the world has ever known.  Yeah, the F-22 is better in an air-to-air role, although you have to compare one F-22 @ $350M to seven F-16s @ $50M.  Air-to-air is rare; air-to-ground is the USAF’s daily bread and butter.Off we go

With a lot of 1:1-scale flying time in the Viper, I’ve been waiting for the right Blk 40 F-16CG model to come along.

Loaded Loaded: 2 x AMRAAM, 2 x Sindwinder, 2 x JDAM, 2 x Drop Tanks, Targeting Pod (right chin), Nav Pod (left chin), ECM Pod (centerline)

F-16The LX version looks pretty darn good, so I pulled the trigger.  Sure, it has a few errors, like 6 hard-points instead of 9, and there are no chin mounts for pods.  It appears to be modeled after a Blk 50, as evidenced by GE motor cues, the IFF interrogator antennas, and the too chubby HARM load-out.  Close enough for RC land.

RC thrust vectoring isn’t exactly scale to the F-16 either, although TV was extensively tested as an incredibly cheap performance enhancement on F-16s.  Thrust vectoring was eventually canned because let’s face it, GE powered Vipers already make the F-35 look pretty shabby in a knife fight.  Even though dog fighting isn’t a high probability event anymore, the F-35 is vastly inferior to a Blk 40/50 F-16 in the phone both, and since government officials generally aren’t sophisticated enough to understand that dogfighting prowess isn’t paramount today, a TV Viper would’ve probably posed an unwelcome threat to the F-35 program.   So, no dice on full scale TV.

It’s interesting how political a life the venerable F-16 had from the outset: first the F-15C mafia tried to squash BVR enhancements for fear of emphasizing obvious Eagle obsolescence.  Then the Viper’s F-35 replacement rolled in at three times the cost and not nearly as maneuverable, so the Viper couldn’t be upgraded further even when it would’ve amounted to an incredible deal for the taxpayer.  Gotta keep the Gucci Suits in business, I guess.  …but I digress.

The LX model looks something like a GE powered, Big Mouth Viper. 

The easiest way to tell the difference between a Pratt & Whitney F-100 and a GE F110 powered Viper is the nozzle.  The silhouette of a Pratt nozzle is straight edged, and it is made up of a lot of turkey feathers:


GE nozzles are rounded, with fewer, larger feathers, and the feathers zag towards the end.  The silhouette is not quite as rounded as the squadron litho below portrays. 


The model has a decent rendition of a GE nozzle with fewer feathers that zag properly, and it looks reasonably rounded.  F-16 savvy dudes will home right in on that:

The intake isn’t quite right for any F-16 variant, but it extends the full width of the fuselage section above it, so I guess it has big lips which is true to the Blk 40 and 50.

LX decided to recreate an ANG 188 Fighter Wing Arkansas Razorback F-16 with a 1986 tail number.  Oddly, the 188 FW doesn’t fly GE Vipers.  In fact, they don’t fly F-16s at all.  They fly A-10s.  The unit converted to Hogs a long time ago, and A-10s are perfect for the Arkansas ANG mascot.  Back when they flew F-16’s, they had older, Small Mouth Blk 32s with F100 Pratt power, unlike this LX model. 

All that said, the BlitzRCWorks model is a great, affordable starting point for what I want to do.  It definitely seems good enough in stock form for RC fun, and it’ll be great fun if it turns out anything like I imagine.

This won’t be a typical build.  I decided to start with the airframe only kit, and upgrade the plane from top to bottom as I put it together.  The price was right at $136:

- Wingspan: 860mm (34 in)
- Length: 1300mm (51.2 in)
- Drive System: 2400KV Outrunner Brushless motor
- EDF Diameter: 70mm

- Construction: EPS
- 2-axis (360 degree) Thrust Vectoring

- Radio:  6-9 channel 


The first upgraded component to go in is a ChangeSun 10 blade 70mm EDF and 70A 2-6S ESC: 

CS 10 Fan Insert
The ChangeSun 10-blade fan has a reputation for great jet sound, big thrust, and even bigger Amp drain. 

ON THE GROUND                                                                   

The airframe only kit shipped in a much more complete form than I expected.  Yikes, some of the assembly could be a little tricky…


Although there are a few pieces in the airframe kit, building the LX Models F-16 is turning out to be pretty straight forward.  There are some steps that cannot be undone, so assembly order is important.  The basic idea is to start with the lower fuselage as a base platform, then build the fuse from the bottom up. 

Just enough finished for motor testing.  Nozzle painted.
The landing gear goes in first, the ChangeSun 10 blade unit went in next. 
I’ll be using a channel for each of the 9 servos (3 gear retraction, 1 nosewheel steering, 2 elevon, 1 rudder, 2 thrust vectoring) so that I can sequence the landing gear, control the amount of thrust vectoring, employ flaperons/spoilerons and even tune the amount of nosewheel steering resulting from rudder movement.

The CS 10 fan seems pretty quiet during initial ground testing.  I took my time balancing the fan impeller and also the included CS 10 spinner using the drill bit technique, and it turned out that both pieces were shipped way out of balance.  That exercise paid off, the first CS 10 motor run was smooth as silk.

With the fuselage together, test power is above 1:1 Thrust:Weight on 5S, but the wings still need to be added as do all 9 servos.  I’m optimistic on this build, it is shaping up nicely.


The internal wiring is as complex as it is permanently sealed inside.  The loose wire is for the tail mounted rudder servo. The landing gear, as usual, is going to be a clear weak point.


42.0 oz RTF without battery


Incredible high alpha slow flier that needs more power than a single 70mm EDF typically delivers.


The completed plane looks fantastic.  I’m flying it clean for the maiden.

The Super F-16’s maiden went very well – for losing the motor.  Seems I made a slight miscalculation thinking the 2850-2200kV motor I installed had enough punch for the ChangeSun 10-blade fan.  Luckily I stayed close to home for a decent forced landing.

The two second streak of white smoke emphasizes the high power consumption of the CS 10 fan.  Thrust was not spectacular pre-failure, either.  The sound was ok, but nothing to write a blog about, either.  It makes sense that if a motor isn’t up to the job, it might not generate enough rpm, thrust, noise, etc, to break into an semi efficient operating envelop. 
So for the “re-maiden” I’ve decided to put two motors on deck:
     1.  Turnigy 4S-6S L 2855 2100kV ($12)
     2.  E-Flight 4S-6S BL32 2852 2150kV ($75)


Turnigy 2855-2100Kv               E-Flight 2852-2150Kv

Since the Turnigy is larger and only costs $12 (a $2 discount popped-up after staring at the page for a minute or two), it’s up first.  It is reported to work well with the CS 10.  If it turns into a smeak of white smoke, I’ll install the E-Flite BL 32.  If that one fires, I’ll throw out the CS 10 idea and go back to the Super F-16’s included 6-blade EDF unit.  I purchased an extra Turnigy L2855-2100 to accommodate that possibility.
The F-16 handled well in the 2 minutes it was airborne.  The CS 10 was clearly shackling the motor; thrust was adequate at best.  I will reserve judgment, good or bad, until I get the power system right.
Re-maiden, soon…

The Turnigy 2855-2100 is installed and seems to be turning the CS 10 pretty strongly.  With a 3300 mAh 5S, T:W is about 0.9:1.  With a 2800 mAh 6S T:W is about 1.1:1.  That’s a lot of push from a single 70mm.  With the stock 6-blade fan, T:W was in the gutter at 2100 kV, but realistically a higher kV motor could be used with fewer fan blades.

More soon…

I got a chance to fly the jet this morning with the CS 10 fan and Turnigy 2855-2100 in perfectly calm winds.  I flew with both 6S and 5S.  6S was definitely the preferred setup given the low gearing of the motor and strong fan.  The batteries were only warm upon landing and the power system seemed fine spinning the 10-blade.

Here is a “re-maiden” video double feature.  The first half shows 6S, the second half shows 5S.

Check out the High Alpha passes in the first and second sortie.    The slow pass at the 9:00 minute mark (handicapped by 5S) got a little too nose high for the thrust output, at maybe +70 degrees or so, but it shows the F-16’s incredible high AOA slow flight potential.  The forward and ventral strakes help the Viper remain stable at crazy AOAs.


The F-16 is an iconic jet for a reason, handling is first class and this RC version is true to scale in that respect.

At high speeds and low Angles of Attack (AOA), the frontal area of the F-16 is skinny, allowing the plane to penetrate like a motor with fins. 

At high AOA, the “Lawn Dart’s” long, needle-nose strakes energize airflow rolling over up and over the lifting body.  The forward strakes redirect kinetic energy into lift, and the nose continues to track up hard while minimizing energy bleed.  But the blended fuselage contributes a lot of wing area, creating a platform with solid turning and hauling fundamentals, it’s not all about Jedi Mind Tricks played on the airflow.   The recent Flanker-E review had a similar long strake config (not a coincidence) and similar outrageous pitchability and control, but lacked the wing area required to fly as slow on the wing.  It was more geared to sustaining high speeds than high turn rates at mid to lower speeds.

Make no mistake about it, the venerable Viper is at the top of its game in a 2-circle rate fight—force a close high speed pass beak to beak, watch your opponent turn first then turn opposite direction to prolong the turning engagement.  Let the awesome power of the GE motor combined with the light weight and low drag of the single engine design, all pile on top of the F-16’s killer aerodynamics and you’ll blow the doors off the other guy’s turn rate.  Result: by forcing both fighters to take the long way around, you’ll be looking down his tailpipe in no time.  Best rate fighter ever. 

You better be in the best shape of your life when this over-powered rumbling spawn of satan crushes you with it’s all-axis acceleration, then never lightens up.  Better have your heavy noggin squared-up over your shoulders when you start, or your giant nugget will fall back, hopelessly pinned to the side of the headrest for the duration of that turn.

As you arrive for the kill, all your opponent sees is the underside of your jet.  The design allows you to pull plenty of lead to shoot while maintaining energy.  With time you’ll learn when to tug hard on the electric side stick and finally bleed enough speed to slow the jet to your match a struggling opponent without overtaking him.  Stitch any pattern you want with the gun spewing 100 rounds per second of 20mm high explosive in a tight shotgun pattern.  

Does my build of the Banana/LX scale Block 50 faithfully re-create that experience?  No. 

The airframe seems capable and scale enough; the missing ingredient is Thomas Edison's GE motor and its avalanche of thrust when you contemplate throttle movement.   The model just doesn’t have the kind of horsepower that shoves the chair into your back or crushes your spine in pain.  EDFs have a long way to go. 


Instruction manual CG is perfect. 

Unfortunately the battery location is well forward of the CG point, making trim calibration difficult with all the LiPo variables still in play.


Too weak to capture the personality of the modern big mouth F-16.

In fairness, I wanted to put the ChangeSun 10-blade in a model as a sub-objective to this build.  There might be better optimized power systems out there. 

I kind of doubt the thrust deficiency is all my choice of 6S 10-blade EDF.  I tested the stock 6-blade fan with a 2100 kV motor on 6S, a reasonable approximation of the stock motor’s 2400 kV motor on 5S and it was not as thrusty.

I think the root problem is a 70mm throat diameter in a fairly large model.  Using CS 10 seems like a decent way to address that issue, but maybe an 8-blade on a little higher kV motor would be optimum.

Before I leave the Power System section, a note on exhaust note: 

One reason I picked the CS 10-blade was its reputation for high fidelity jet noise.  I found that claim to be a little overblown (ha ha).  It is definitely a quiet EDF as far as EDF’s go. I think the “whoosh component” of the sound has a better chance of burning through
the overall racket produced by lower blade count EDFs.  But that doesn’t really make the whoosh sound louder.  Close passes are the key to hearing high quality air rush. 


King Kong.  Enough said.


Approaches were very well controlled.

I wondered if the F-16 would need flaps and/or slats to land slowly/gently enough.  The answer is: sort of. 

The plane has such bad a$$ high AOA control that you can slow way down, under complete control, and drag the nozzle all the way down the runway.  The question is, how do you get the wheels on the ground before the nozzles and ventral fins are ground into stubble?  In that sense flaps or flaperons (the elevon setup removes that possibility barring inserting more servos) would help.

I’m still working on this one. 


- Servo-driven main landing gear are too weak to overcome the airflow during retract. 
- Landing gear piano wire is too thin gauge for the weight of the jet; needs a complete servoless re-design.


In general, this model is a fantastic flier.  The lingering questions are:

1. How to best power it with today’s 70mm EDF technology?
2. Is there better way to get it on the ground than smushing a jumble of servos and toy landing gear after each sortie?

A puzzle worth solving.  I’m going to iron this one out some more and update.

Update:  Just tooling around:


Appearance: A+
One of the best renditions of a desirable F-16 Block 50.

Aerodynamics: A+
Unmatched handling and high alpha control, just like the real thing.

Power System:  N/A
Not included.  Scale of jet is difficult to power sufficiently though the 70mm form factor.  The ChangeSun 10-blade has plenty of static push on 6S, but not dazzling top speed. Maybe a 3200 kV 6-blade on 5S, or a 2500 kV 8-blade on 6S would do a little better.  Limited to 6S due to battery bay/scale constraints.  10-blade fan eats batteries and ups weight. Slippery jet helps conserve fuel between blasts.  

Build Quality/Durability: D+
I purchased the airframe only.  Soft foam needs edges taped and inlet reinforced.  Stock landing gear is awful.

Value:  B-
@ $136 for the airframe there is $ enough left to populate with quality components, even to re-design the landing gear. 

Overall Grade: B
Iconic handling is worth the hassle.  My mistakes are your gain.

Thursday, August 23, 2012

Gemini RC/Mini-Air Extra 300 Flight Review


A new line of Ultra Micro aircraft has hit the streets and is being sold under the names Gemini RC and Mini-Air.  How do these mini me wannbees stack up to more established offerings from Horizon Hobby and Hobbico? 
It’s time to find out…
The first question that needs to be asked: are these brands even different from Horizon and Hobbico offerings, or are they just another attempt to create faux competition from shady multi-identity companies like Horizon Hobby fronted E-Flight, Parkzone, Blade Ares, Losi, Athearn, Blade, Dynamite, E-flite, ElectrixRC, Force RC, Hangar 9, HobbyZone, Pro Boat, and Spektrum product lines?
The Gemini model I purchased seemed different from established brands in some ways, and similar in others…
Not so similar are the instructions, which are minimmanualal and printed on poster-sized paper, instead of Horizon instruction manuals’ usual parade of legal disclaimers mostly devoid of useful RC content.  The servos are not the usual UM linear garbage peddled by Horizon, but could that be a strategy to improve without admitting liability for their existing defunct designs flooding hobby store shelves.  The control rods are more substantial, as are the thicker but similar looking control horns.  Hair thin control rods popping through paper thin control horns is certainly a plane-killing manufacturer defect common to Horizon’s UM line, so it would be a smart thing to finally begin to correct.
On the similar side of the Gemini/Mini-air offering, the Gemini website uses the same text format for their product html links, for-example-the-dashed-product-description-html-links-which-oddly-include-the-branding-term-Bind-n-Fly-even-though-the-product-web-site-seems-careful-not-use-that-term.  The models also use an antique, tiny brushed 8.5mm motor, which could be a Horizon strategy to draw down obsolete motor stock.  The built in Rx is Spektrum BNF compatible, and the Gemini website might pay too much homage to Horizon “TM” trademark annotations from my understanding of Chinese manufacturers’ cultural ideal that “borrowing” technology is clever, honorable and legally permissible.  The foam looks similar to Horizon UMs, but that could be because all major brands share the same Chinese roots.  Su-26 recreations certainly do look strikingly similar.
General build quality is very much on par with Horizon UMs: Poor, generally toyish junk that doesn’t last.  It is eerily similar in that regard. 
The listed distribution centers seem unique to Gemini, but the lack of a listed corporate headquarters makes me wonder if Horizon didn’t learn a hard lesson from my immediate unearthing of their latest consumer scam – the claimed independent Ares RC co-founders -- which I quickly proved were on the Horizon Hobby payroll.  Dishonest scam artists.
We know that at least two brands of the same model line exist, which essentially rules out a new single entity emerging the marketplace.   
So for now: let’s say, “not enough information” to make a certain call. It sux that one of the larger influences in our RC market place has so little respect for their customers that they often re-release inferior product technology (like 5 cent wimpy brushed motors) using intentionally misleading, phony and deceptive re-branding.

Top:  Gemini RC Extra 300
Bottom: Mini-Air Extra 300

- Wingspan: 16.1”
- Length: 15.1”
- Weight: 1.34oz (38g)
- Battery: 1S LiPo

- Display stand with integral 1S LiPo charger
- Wimpy 8.5mm brushed motor

- Spektrum or DSM transmitter

- $70

- None

ON THE GROUND                                                                   




 The usual UM experience.  A little too much like Horizon UMs for those seeking something different.


Poor foam quality.  Better servos than typical Horizon Hobby linear garbage, better horns, and rods.  Full foam symmetrical airfoil--nice!  No trace of carbon fiber.

The motor and gear box are very smooth, quiet, and efficient.


  1. Landing gear wire insert did not fit well into the plastic receptacle.  The gear kept wanting to partially pop out.
  2. Aileron droop on one side was difficult to bend straight due to the springy metal control rod.  25% Trim/Subtrim required.
  3. All three wheels do not spin easily = poor ground handling.

IN THE AIR                                                                              


Not enough power.


The Extra handled reasonably well for a UM.   Wings have a slight anhedral slant, which is probably a mistake, but overall stability was average to slightly better than average for a micro.

Control throw was excellent in roll, good in pitch, and average in yaw.  50% travel, 5o% expo worked well for low rates in both roll and ptich, with 100%/50% in yaw set for both rates.

The slippery airframe and efficient motor cruises effortlessly on 25% power and 20% nose-up trim.


Rolls rate is excellent to outstanding.  Snap rolls are outstanding. 

Loops are strained eggs from a lack of thrust, even when entered from a full speed downhill trajectory. 

Spins are excellent, extending the plane’s love of precisely entered/exited, crisp snap rolls.  Inverted spins are possible but not very flat even with power applied.

Knife edge is mostly uncoupled, with a slight need for down elevator.  There is probably enough rudder authority, but not enough power to maintain altitude on a 90 degree KE.  Bummer.

Hovers are not possible primarily due to a lack of power.  The lack of blown thrust creates marginal to inadequate rudder authority to hold the nose in the vertical on 100%+ throw.


Weak.  Very efficient.  10 minute flight times on a 150 mAh 1S. 

Serious design flaw: elevator jumps to a down-position upon LVC, causing a guaranteed face plant.  Do not fly the battery to exhaustion.


Not 3D enabled, though control throws would probably be good enough with more blow. 

Stall behavior is a mixed bag.  The airplane’s stall behavior is actually fairly benign when well coordinated, which requires 30% right rudder during ragged-edge slow flight.  The plane porpoises slightly as the sym airfoil bobs above and below critical AOA.  No airleron is required, there is slight positive roll stability throughout the stall sequence and the plane tracks straight and level.

Minus the right-rudder coordination, expect a slow to moderate snap roll to ensue at the edge of slow flight.


The plane glides nicely with the nose up using a battery-forward CG.  This generally leads to smooth, low power or power-off approaches and well controlled touchdowns. 

The plane is impossible to glide or land after LVC.


  1. Design flaw:  Plane augers-in after LVC, spinner first.


Appearance: B
Nice.  Don’t expect stunning.  Narrow stance; odd looking gear.

Aerodynamics: B 
Well mannered and largely uncoupled.  Nice snap rolls and glides. 

Power System: D+
Weak.  Very efficient.  Perfect for a high-wing aileron trainer.

Build Quality/Durability: D+
Typical for a UM.  Quirky LVC behavior: plane goes stupid.

Value:  B
Price is right.   Let down by foam quality and lack luster thrust. 

Overall Grade: C-
Sorry Gemini, thanks for trying!  Low cost.  Significant flaws.

Saturday, August 11, 2012

Align TREX-500 ESP Flight Review

It’s time to review a couple of helis… first up is the venerable Align TREX-500:


I’ve reviewed an awful lot of Blade helicopters, from toys to the entry level Blade 400:


It seems past time to review a more serious helicopter or two.  I’m not a good helicopter pilot, but I know enough to be extremely dangerous. 

No doubt about it, the Align TREX series defines the standard in high-end copters.  The 500 is a classic, maybe because it sits right at the bottom of a more serious class than your typical RTF offerings, which used to top out at around 400 size, but are currently breaching the 500 class.  

Align TREX 500 ESP

T-Rex 500 ESP Superior Combo Features
* Electric power system.
* Simple and light weight design provides awesome flight performance and extreme 3D capability.
* Rigid carbon fiber frame design.
* Beautiful factory painted fiberglass canopy.
* Rotor head/tail with thrust bearings.
* Direct-to-swash CCPM linkage.
* Center of gravity of Battery tray designed close to the rotor head.
* High efficiency torque tube drive system.
* Fully driven tail auto rotation system.
* Tail servo boom mount.

T-Rex 500 ESP Superior Combo Specifications:
* Length: 840mm
* Height: 310mm
* Main Blade Length: 425mm
* Main Rotor Diameter: 970mm
* Tail Rotor Diameter: 200mm
* Motor Ponion Gear: 12T/13T
* Main Drive Gear: 162T
* Autorotation Tail Drive Gear: 145T
* Tail Drive Gear: 31T
* Drive Gear Ratio: 1:13.5:4.68/1:12.46:4.68
* Weight(w/o power system): 1370g
* Flying Weight: Approx 1700g
* Color carton: 48.3x18.7x9.8cm
* Outer carton: 58x50x42cm ,12sets/ctn

Included in Kit:
* T-REX 500 ESP Kit Set X1 set
* 425D carbon fiber blades X1
* RCE-BL60G 60A Brushless ESC X1 (Built-in 5-6V step-less adjustable BEC)
* 500M Brushless motor X1
* Motor pinion gear 13T X1
* DS510 Digital Servo X3
* DS520 Digital Servo X1
* GP780 Head lock gyro X1
Radio transmitter and electronic equipment required for assembly:
1. Transmitter (6-channel or more,helicopter system)
2. Receiver (6-channel or more)
3. Pitch gauge X1
4. 22.2V 6S Li-Po 2100~2500mAh battery X1

Another trend in hobby grade RTFs is the move toward flybar-less heads.  A mini techno revolution is clearly taking shape in micro electronic gyros, which have the potential to replace mechanical stabilizers, like flybars.

Perhaps because the TREX-500 used to enjoy more exclusive rights to the 500 class, and it is still sold with (and without) a flybar, it is priced very aggressively for a pro-class heli.  In my view, this confluence of current events and trends has created a sweet spot for the Align TREX-500, particularly for those wishing to make the jump from cheaply built RTF helis, to a more reliable and much better flying steed.

Interestingly, Align’s marketing model is “Made-in-America” as opposed to other brands which are put together in China.  Well, that’s not exactly their model, their business model is “Make-it-in-America” (<—or, insert your country here).  The not so minor catch being, you have to build it yourself or find someone else to build it for you. 

Building a helicopter of this caliber sounds daunting, because it is…


…but there are real benefits to building a helicopter yourself, namely:

  1. You understand it in and out
  2. The heli was built by someone who gives a $#@%

These are not small things.  Consider:

  1. You might not build an RTF heli, but you will have to re-build it
  2. Nothing is worse than an un-threadlocked screw coming undone or <insert any other super cheap weakest link here> tubing your entire investment

Both of those things will happen. 

Example: In spite of religiously staying within my comfort zone (because I dreaded the thought of re-building something I that did not build) and subsequently never getting sideways with my heavily upgraded Blade 400, the tail blew apart when a hot bearing melted through the ridiculously cheap, stock plastic tail casing. 

So as the saying goes, if you want something done right you must do it yourself. 

The first thing RTF heli buyers are likely to notice when examining the TREX 500 is a pretty eye-popping increase in industrial grade component quality compared to lower end builds. 


There are other quantifiable differences, like a 6mm feathering shaft instead of 5mm that comes in other popular 500 helicopters, etc.  The quality of Align’s offering is evident from every angle except the price tag, which is a little higher but clearly heavy on value.  These are the kinds of price tags worth paying.

A quick look at a major retailer’s price page shows the TREX to be price competitive, especially considering the well known brand quality and large user base:

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