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Tuesday, August 30, 2011

Blade CX3 Flight Review

Update:  Downgraded to D+, see:  CX3 on 3S

Update:  I decided to try an aluminum swash to see if it improved the precision of the heli. While I had it apart, I manually balanced both sets of blades which were out of whack as shipped. To my pleasant surprise, the combination provided a big improvement in precision and handling.  I think part of that difference isn't the actual function of the swash plate, but fatigued plastic ball joints giving a little bit under the substantial force of normal flight.  Unfortunately, before I could enjoy the $20 upgrade, one of the shoulder pins on the lower head (which is plastic; the upper hub and shoulder pins are aluminum) sheared during a stabilized hover, making the heli vibrate moderately and perpetually drift right.  Looks like a another $15-$25 for an aluminum lower head.  And the CX3 is down again for maintenance.  

The good news is I'm convinced the copter can be made to handle much better than stock.+$40

I was never interested in the CX, CX2 or CX3 at $180, but recently I found a CX3 BNF version selling for $119 in my LHS (also on the web).  That did the trick, so I snagged one.  I'm happy I did.  Although this CX3 has about the same capability, and is overall less stable and more twitchy than my mCXs, I think the larger scale makes it more fun.
 I've never been in love with the MD 520N Police body that ships standand on the CX3, but after living with it a few days I like it better.  I tried to remove the "Police" sticker from the tail boom, but with a small corner peeled away, the sticker began to disintegrate, so I left it in place.
There are several compatible bodies available for the CX2 and CX3 available, they run $20 to $40 and include a Blackhawk and a classic Jet Ranger.
Looks aside, the CX3 advertises a few improvements over the CX2, namely a heading lock gyro, an AR6100e Rx, and an aluminum head. I don't have a CX2, so I can't compare to one of those.  But I do have several mCXs, and they are roughly 25% more stable in a hover than the CX3, and they seem about 40% more maneuverable due to the lighter mass.

The mCX also has better heading stability than the CX3 and is easier to trim out.  If the CX3 gyro has better heading control than the CX2, then I would not purchase a CX2 as the CX3 nose has a tendency to wander quite a bit, especially with power changes.  I suspect my upper and lower blades may not be well matched out of the box, causing the heading to drift a little with power changes, but I have yet to replace them so I'm not 100% sure.

The CX3 is also unique in that it has no tail boom integral to the helicopter frame, the boom is part of the body design.
All that said, even if you've never flown a decent RC helicopter, you are in for a treat.  The CX series is easy to fly in a reasonably large room inside your house.  The counter rotating coaxial design eliminates the need for a tail rotor to counter single rotor torque, and the long shaft results in a pendulum effect that inherently stabilizes the helicopter, somewhat similar to a high wing airplane's gravity-power tendency to return to level flight.

The fairly large size of the CX3 (13.6" rotor diameter) makes it a lot more impressive and less toyish than the mCX or mSR series, making it more fun.   At 8 oz flying weight, it is roughly 8x larger, but still not large enough to seriously injure some one.  The 8x larger size has the unpleasant affect of making your room feel smaller by about 1/2 in each linear dimension (= 1/8th scale) compared to more cooperative micros.  The CX3 is definitely more of a handful in any confined space.

Maneuvering the CX3 is straight forward and reasonably predictable.  The CX3 is too sensitive in yaw, and about right in pitch and roll.  A programmable radio with rates and exponential tailored for each axis makes a huge difference in how the helicopter handles and trims.  You'll want a DX6i or better.  Interestingly, the heli uses a proper receiver instead of incorporating an integral Rx in the motherboard, raising the possibility of using a better brand of Rx/Tx.  I might convert it later.

Durability seems good, but Quality Control is iffy.  My CX3 had a high frequency tail wobble right out of the box.  Horizon's site has posted a fix on their website to reduce the gyro gain, but I wasn't convinced it was a gain issue since it seemed inconsistent while holding the heli running in my hand.  Shaking the heli a little produced the gyrations, it seemed more like a loose gyro platform than a gain issue.  Taping the gyro firmly to the plastic shelf fixed the problem entirely, though the shelf where the gyro sits is weak and very pliable.

Another strange issue is the usual stance of the body.  The rotor shaft is canted backwards when the heli sits normally on its skids.  Why?  I don't know.  But it makes it harder to takeoff without drifting backwards, especially from a soft surface like a rug or cushion where the amount of forward control authority can't overcome the rearward vector.

This is a good first helicopter.  It is easy to fly, can take a hard crash or two, looks great in the air, has good flying time, and the price is marginal but acceptable.   If you are starting from scratch, or buying for someone less than mechanically inclined, the smart thing to do is forgo the larger scale CX3 and spend less on a smaller, lighter, less expensive, and better flying mCX.  But if you value a little more fun over frugality, go for a CX2 or CX3.

Appearance: B-
Good size and presence.  Selection of police body seems adolescent.

Flight Performance: B-
Stable design is not very maneuverable, nor designed to be.  mCX is better.

Build Quality/Durability: C
Gyro platform was loose out of the box.  Cheap swashplate.  Crash survivable.

Value:  C-
Nothing special at $119 BNF, but better than it used to be. Needs aluminum upgrades.

Overall Grade: B-
Cool factor is high for the money.  Not the best flyer its price range.

Monday, August 29, 2011

Z8RC Goes Exponential

Page views
I would like to thank those who visit Z8RC for a 10-fold increase in readership during a brief year of existence.  Thank you.  It is amazing to me that in today's day and age there is such a thirst for ground truth that a formula as simple as "don't lie like crazy" in product reviews works so well.

I don't usually editorialize on non-RC related topics, but this reinforces my belief that what we view as a great age of enlightenment will be judged very harshly by history, as a second Dark Age for mankind.  A time when truth-telling was systematically attacked and stamped out, when the mass media came into vogue to keep people ignorant and in debt, when doctors were so helpless they pumped the masses full of high-profit pills and radiation which caused long term degeneracy, then sliced off body-parts at the first sign of cancers caused by their own quackery, when a multinational corporate aristocracy emerged to purchase everything political so common people had no say, when governments cheated their own people by partnering with central and commercial banks to counterfeit whatever money they needed to keep the scam going.  The last great experiment, the U.S. Revolution, has failed rather spectacularly over the past century's time; it seems our generation's special privilege will be to witness the fireworks of collapse.  I'm fortunate to have a cushy spectator seat, but many won't be so lucky.

It is a very sad time in human history, about to get much sadder, but little successes prove that the human spirit is unstoppable and will eventually prevail.

Saturday, August 27, 2011

Blade mSR Flight Review

For heli-begginers, there are few things as easy to fly as a Blade mCX.  That's good because beginners can learn basic orientation with solid success, upfront.   It's bad because any step up from "easy" is a big one.  The mSR is a big step up from the mCX, but flying it is really not super similar to a larger, CP single rotor heli even though the mSR is presumably, a micro-SR.  Oddly, it preceded the SR, but clearly mimics the look of its big brother:
All that said, the mSR is good first step into fixed pitch single rotor RC copters.  Not because it is easy to fly or because it simulates larger helis in a less expensive package, but because it is reasonably durable.  Beyond durability, the mSR's Flight characteristics really don't fit the previous sentence.  It doesn't fly like an SR, though it is a lot  closer than a CX or mCX.  It is much easier to hover and control, pirouette and drive with a purpose than an SR, which is really just a glorified, rather unstable Blade CP.  The Blade 400 is both easier to fly and much more capable than the SR, making it an unlikely competitor with the mSR.

Thankfully, the mSR shares no DNA with the squirrelly SR evolution of the CP.  Less fortunately, it flies closer to an mCX than it is to a large single rotor parents.  Like all electric tail copters, yaw is imprecise and the stabilizing influence can be overwhelmed during aggressive maneuvering.   The spin up and spin down time of an electric motor never really feels "locked in" and you hear a constant warbling buzz to prove it.

The mSR is also a fixed pitch, not a collective pitch whirlly bird, which is one less variable and generally easier to operate.  Once the mSR starts zinging forward, it wants to roll due on the fundamental FP design.    The FP rotor's quirks all add up to pretty big difference from larger single rotor helis, ultimately limiting the mSR training value.

Though much hard than a coax, it is reasonably easy to hover the mSR, and with a little practice an advanced novice will be flying coordinated circles and boxes.  This angry little bumble bee (the sound it of the tail rotor always playing catch-up) can take a decent crash usually without damage, and it is slightly easier to fix than a coax.  All this adds up to a cost effective stepping stone to a larger, more capable heli.

The question is: it the size of the step up worth the money?  I think that's going to vary with one's perception of the cost.  If $100 is a lot for you, I would put that C Note (+) towards a Blade 400/450 and skip the somewhat unique mSR.  If $100 is chump change, then why not add a few skills before tipping over a bigger copter?

The toy radio in the mSR RTF version is definitely too vague and loosey goosey for the MSR, but it works (barely).  I still like my idea, buy the Blade 400/450 with a DX6i to get a small package discount, then bind the mSR BNF to the better radio while the 400/450 awaits your skill set.
Forget about enjoying the mSR with the toy radio, but it can be flown.
Overall, like many micro RC contraptions, the MSR is a little frustrating because it can fly too fast for indoor flight, but at 1 oz including the battery, any wind is going to blow it away. It's a fun little copter without a reliable venue.

Good or great things: much more maneuverable than a coax, quite fast, very good durability, single rotor, sounds angry, extra tail rotor and mixing flybar, comes with two batteries (uses one at a time) and a great 4-battery charger with a wall plug.

Frustrating: Unstable in a light wind, too sporty for the basic transmitter, FP blades don't mimic larger CP copters, flight time is short.

Appearance: C+
Ok.

Flight Performance: B-
Fast, maneuverable, squirrely electric bumble bee tail.

Build Quality/Durability: A-
Shrugs off most crashes in idle.  Swash plate finicky.  Flimsy tail rotor. 

Value:  C-
Largely obsoleted by the 120SR.  Nice charger.

Overall Grade: B-
As a stepping stone to CP: half useful, half FP anomaly.  No real itch to fly it.

Friday, August 26, 2011

E-flite Jenny JN-4 Slow Flyer Flight Review

Update: Videos added.

They don't make 'em like they used to.
WCL of 2.4 for $55?   Heck yeah it is coming soon...

- Wing Span: 32 in
- Overall Length: 26 in
- Wing Area: 304 sq in
- Flying Weight: with Battery 7.5–8 oz; without Battery: 6.9 oz
- Motor Size: 250-2200 Kv
- Radio: 3 channels with 2 super sub-micro servos
- Servos: S60 Super sub-micro
- Prop Size: GWS 6x5 slow flyer
- Speed Control: E-flite 10A Pro Brushless
- Recommended Battery: 480 2-cell Li-Po
The colors are stunning.
On the Ground:

The E-flight Jenny is an interesting foamie.  The ARF is made of 1/8" thick foam sheeting.  The fuselage is pre-built from flat and curved panels already assembled and painted, all you have to do is foam-safe-glue-on the horizontal and vertical tail with stamped, pre-hinged surfaces.  Even the pushrods are pre-installed in plastic tube casings.  The painted wing is stamped with molded rib detail that strengthens the chord and span.  Wooden braces quickly glue into place.  The wing box is further strengthened with supplied thread rigging.

The resulting airframe is quite strong for it's size and silly light weight.  At 32", the plane certainly isn't small and carries over 300 square inches of Wing Area.  At 7.6 oz RTF with a 5 minute battery, my finished sample has amazingly light Wing Loading at just 3.6 oz/sqft.  It's Wing Cube Loading is even more impressive measured at only 2.5.  These numbers are hard to beat, and that fact showed up loud and clear in the flight tests.

For electric guts, I selected a 0.52 oz Common Sense RC Brushless Outrunner 250 and 8g SkyRC 10A ESC.  I elected to put a longer than stock shaft and prop adapter on mine for easy prop changes.  But the instructions call for a prop-saver with O-ring type of prop adapter, which is how the motor comes set up by default. I used two 4.4 gram Turnigy sub-micro servos and a Hitec Optima 6 Rx with built-in voltage telemetry.I removed the hard plastic case to lighten the Rx to 18 grams. The system worked perfectly with no installation issues.

The Park 250 Brushless Outrunner Motor has a small round bearing case that fits snugly into an included carbon fiber tube engine mount, which then slides into matching circular holes in the firewall an first former, making it very easy to install and align.  The downside is that the changing the thrust angle is very difficult.  I elected to go with the Common Sense RC motor instead for better power and durability.

For ease of motor installation, is simply zip-tied the motor's three mounting feet to the Jenny's thin plywood firewall using the pre-cut holes.  I slid a small plastic shim under the top motor foot, to adjust the thrust angle about 2 degrees down from center-line.  This turned out to be perfect.


The instructions are pretty good, and make it clear that the most important aspect of the DIY part of the aircraft build is warp-free wing box.  I was very careful to align the wings with triangles while assembling and glueing.  Then, sure enough, when the glue dried it turned out to be slightly warped, with more incidence on the left than right wings.  Fortunately, I was able to twist the wing into perfection by installing the included string rigging.  I glued the string in place under just the right amount of tension to straighten the warp.  Finally, I soaked the string with CA for good measure.  The string rigging is not shown in my pictures.
Classic lines make the JN-4 a convincing barnstormer, 
but at 3.3 oz Wing Loading, Jenny is rarely in a hurry.
In the Air:

My Jenny now has two flights under it's belt.  The first flight was in perfectly still air, and although my thrust angle was off a little (more on that later), I was able to explore the entire flight regime and a little beyond.  The second flight tested a new thrust angle and started in 3-5 mph winds, progressing to 5-10 mph, and eventually forcing an early landing to keep the plane from being blown off site.  The second flight is captured in the video below.

Let's discuss the first flight then the second.  I originally tried a neutral thrust angle in the vertical, with about 2 degrees right vector.  The Jenny lifted off wonderfully controlled after a 3-5 foot take-off roll, and tracked perfectly into the blue.  Once trimmed for a light criuse, the WWI relic was a joy to fly.  The plane's nose pulled upward with throttle, which is possibly ok, but in idle the plane dove for the ground indicating that the up-thrust-vector was holding the nose up during cruise with a nose-heavy CG.

My estimated fix was simple: move the ESC farther backward under the cowl and above the servos, then move the Velcro battery mount back to just in front of the low wing leading edge.  The plane balances only about an 1/8th inch behind its recommended CG location this way, as my first flight was slightly nose heavy by intent.  I also added about 2 degrees of down thrust, which by the nature of the required mounting shim location, took out most if not all of my right thrust.  I decided to do the second flight this way, since the plane tracked perfectly during the first flight, from idle to mil, and I wasn't sure if it would track perfectly regardless of a slight left/right thrust angle.

During the second flight, CG and vertical tracking were absolutely perfect.  The plane didn't budge from level flight as the power came out.  The Jenny's climbing tendency under high power was better controlled, and given the copious thrust available, just about perfect.   Generous right rudder was required at slow speeds and high power settings, indicating that the plane needs the 2 degree right thrust angle put back in.  That is all set for flight number three.
Second flight with the Jenny.  Down thrust line is perfect 
but needs the 2 degree right thrust vector 
put back in. Loops at 4:03.
All that said, it was easy to evaluate the JN-4's flight characteristics while ironing out the thrust angle.  I'll state it succinctly:  this WWI vet is fabulous.  Feather-light Wing Loading gives this plane a floating speed very comparable if not slower than an Ultra Micro class high wing trainer.  Stability is perfect, not hard to turn, but easily finding a hands-off arrow-straight line through space.

My stall series went much better than I expected.  I expected the under-cambered wings to hold on to lift til the very end, then dump the nose all at once.  Not the case.  Stall onset is as gentle as can be, and as long as you don't change very much very fast, the plane only shudders almost imperceptibly, plowing along on its intended flight path.  The wing tips stay level.  Wing rock is initially all but absent, then slowly develops into a steady cycle that I would classify as "slight."  What a wonderful surprise.  The plane can be coaxed down to explore its eerily slow lower airspeed limits, and it won't snap at you when over stimulated.

Not perfect, but to be expected from an ultimate floater:  top speed is with an 8x 4 Slo-Fly prop is pretty good, faster than a UM, but requires significant down elevator and that makes it little hard to balance the pitch inputs during short "high speed" bursts.  Although rudder control authority is just right, ailerons would definitely take control to a new level.  The weight of the additional servo might steal of tick of the low speed fun, but there is so much margin there to sacrifice that I think it would be a good trade--and I love floaters.

Loops are uncanny-tight for a 32" span airplane, completing in approx 5 feet of altitude.  Rolls are limited to very positive Barrel Rolls, and resemble one turn of a gentle spin on 30 to 40 degree forward-down vector, unless entered about that much nose-high.  General flight control is outstanding for a 3-channel.  4-Channels would make an interesting upgrade.

Landings are cake in calm winds, easily flared and floated into a wheel-dancing 5-10 foot roll out.
In too much of a hurry, E-flite used the top photo to erroneously 
conclude the tail marking was "FUI" instead of "FUL"
Jenny's gorgeous profile view gets better with age
One minor quibble is the beautiful color scheme.  It is pale yellow on top and white on the bottom.  While highly visible (yellow is generally the best color for vis), the translucent nature of the wing foam effectively tints the ground-up view in sunlight to almost the same pale yellow color as the top.  The insignias also bleed through the foam to an extent, making the plane rather hard to orient against any bright sky.

Of course, this plane becomes a handful above about 5 mph of wind, but at 7-8 oz it is more wind tolerant than an Ultra Micro and flies in about the same space.  I incorporated a wind test into my second flight, by flyingmy most wind-tolerant micro plane, the UMX Sbach just a few minutes after landing the Jenny for winds.  The Sbach was a lot worse and virtually uncontrollable in the same winds, as shown in the (short) video clip below:
Same wind was too strong for my most wind-tolerant micro
I love flight reviews like this one: "Inexpensive plane promises the world and delivers the Moon, too."  Horizon's  E-Flight JN-4 Jenny deserves high marks for shacking the supreme floater target, dead center.


Appearance: A
Beautiful pastel scheme.  Classic lines.  Highly visible, but difficult to orient in the air. 

Flight Performance: A
Masterful slow flight .  Stalls as gentle as can be.  Limited as a 3-ch.

Build Quality/Durability: C+
Couldn't ask for more at this price point.  Foam gets more brittle with age.

Value:  A
A fair price for the ARF level of completion and workmanship.  Great scale for the money.

Overall Grade: A
3x Bulls-eye and a reasonable price to mitigate the last.

Tuesday, August 23, 2011

Flyzone Albatros Flight Review

Update: Video added. 

After solid success with the intermediate-level BlitzRCworks Nano Corsair, I thought it would be interesting to test a beginner non-Horizon micro. At my point in life, I enjoy a calm morning or evening of relaxed flying, so why not.  I found a little Flyzone Albatros with my name on it. 

It specs-out something like this:
• Ready to Fly
• Flies for up to 10 minutes
• Recharges from the radio
• 3-channel control
• 2.4GHz radio system
• Wingspan: 14.5" (370mm)
• Length: 11.1" (280mm)
• Weight: 1.0-1.1oz (28-31g)


A small transmitter is included, and AFAICT, is the only option to control the plane:
The included radio is tiny and the trim buttons,
built into the stick bezels, are very difficult to use

On the Ground:

Like most micros, the plane comes fully assembled in a large-ish box sufficient to protect it from most nuclear blasts.  All you need to do is charge then Velcro the battery in place.  As you can see in the upside-down photo, there is no forward-aft play in the battery position, so the aircraft CG is fixed in one position.  No doubt, the manufacturer wanted to keep the flight characteristics amenable to beginners, and they succeeded in doing so at the expense of satisfying intermediate+ flyers.  The plane balances nose-heavy.

Build quality of the airframe is poor, like most micros. The wings are stamped from thin foam sheeting and the fuselage is semi-permanently sealed.  The sealed fuselage wouldn't be a big deal if my little bird's gearbox didn't fail after one flight.  One the second takeoff, the shaft pulled far enough forward to disengage the propeller reduction gear.  About three seconds after breaking ground on my first flight, one main wheel fell off.

In the Air:

Like all good early designs, the WWI Albatros takes advantage of advanced aerodynamic principles that modern designs use computer-driven flight control systems to overcome on the cheap.  In RC terms, that means older designs usually fly real good.  Biplanes, in general, are inherently great flyers, which is why nature invented them perhaps 130 million years ago:
Advantages of the biplane are many.  There is improved ability to brace more wing area, higher aspect ratio wings have less overall span, wing area is concentrated near the longitudinal axis for roll authority, the form can be made symmetric without a stabbing a main spar through the pilot or fuselage CG point, more wing area gets blown by the prop for better lift and control, and the pilot gets a better view of the ground with the reduced low or mid wing requirement.

All of these advantages (ok, maybe not the pilot visibility part) are at play with the tiny Albatros, and in the air, it showed.

Flyzone's micro Albatros is an excellent flyer.  The WWI era tail skid works well enough on pavement to taxi and even turn with a prop blast.  The wheels are large for a micro, so short grass might be a player.  Take off is reasonably short and well controlled even without a tail wheel. 

Once airborne, inherent stability is enhanced with pronounced low wing dihedral and some upper-wing dihedral.  The plane settles into a straight-ahead grove very nicely.  When you want to change course, the reduced span of the design (28" of wing crammed into a 14.5" span) allows good maneuverability with only rudder control.  The wing dihedral helps keep the rudder from coupling to a nose down tendency when established in, and rolling out of a turn.

Control throws are too small, especially for the forward CG location.  This makes turns overly wide and landings too fast, or the nose will plow-in.  Even beginners will want to move the two push rods to their inner most holes on the control horns. 

Slow flight and stall characteristics are the best thing about the Albatros.  The plane can fly under very low power and at very high Angles of Attack without drama.  Unfortunately, the radio can't.  Airborne elevator and rudder trim are way too cumbersome to operate continuously during flight; the buttons are embedded in the stick bezels making them hard to find and they require too much force to register.

An unexpected pleasure and pain is the amount noise pumped out by this mini Albatros' over-taxed motor and gear box.   I found the Chitty Chitty Bang Bang nature of the drive system actually added to the WWI appeal of the bright red and black-crossed floater, as it clamors to stay afloat.  Your neighbors' dogs might disagree.

A main wheel falls off and bounces on the ground 
below the plan at the 9 second mark

Overall, this plane flies great.  Unfortunately, Flyzone limited the fun with a nose heavy condition that can't be corrected with battery position.  One might experiment with a lighter battery than the stock 130mAh, but then flight times are going to be hampered as they are only "ok" as sold.
The plane has a few nice little scale details. 
The fuselage foam is much better than the wing foam.
Word on the street is that a Dr.1 Triplane sibling will land in stores soon.  Let's hope a Futaba 14MZ radio is included instead of the Albatros' mini stock radio.

Appearance: A-
Nice little scale replica.  Color scheme is snappy, highly visible and easy to orient in the air. 

Flight Performance: B
Excellent stability and low speed handling.  Poor radio trim controls significantly detract from flying experience.  Too nose heavy with no way to alter battery position.

Build Quality/Durability: F
Disposable build quality. Dropped a wheel on the maiden flight.  Gearbox play decoupled the prop reduction gear on the second takeoff.

Value:  B-
Decent price for an RTF at under $80.  Radio is hard to use with no way to upgrade.  Manufacturer-limited intermediate+ flyer appeal.

Overall Grade: D+
Wonderful flight characteristics limited by lack of throw and clumsy CG. Locked into a poor radio. Un-flyable gearbox after one flight.

Monday, August 22, 2011

Fixing Spektrum's DX6i Trim Button Defect

Update: Two more trim buttons broken and a dual rate switch jammed immovably.  This radio has a useful life of about one year before a switch and button overhaul-- moved to my AVOID list.


***** This safety bulletin affects all Spektrum radios with plastic trim buttons *****
 
Sometimes there is a fine line between breakage from normal wear and tear, failure from a design flaw, or a dangerous product due to the manufacture's negligence.  This flight control issue is the latter.

Looking back, the DX6i was a much better deal than my horribly lethal DX8, which I finally destroyed out of concern for my fellow man.  It also has had fewer issues, with the exception of an unsafe lack of throttle-high signal cut out during binding and model initiation.  So after I ditched all of my Spektrum gear in favor of Hitec radios, I retained my DX6i specifically to fly micros with integral receivers.

My 6i isn't exactly old, nor had it been used that much.  But in typical Spektrum radio fashion, it tried to destroy a model today when the elevator trim tab stopped trimming forward and would only trim backward.

After inspection of the interior switch mechanism, it turns out that all of your models and the safety of those within crashing distance rely on a 1/32" thick, ultra cheap plastic tab not breaking -- two of them, actually, for each stick direction, or a total of 8 tiny plastic tabs just itching to surprise you.  This radio is a ticking bomb.

If that isn't bad enough, it turns out that Spektrum knows all about their DX6i's flight control defect, but couldn't care less that it is dangerous so long as they make an extra 1 cent per radio sale.  How do I know?  Simple.  Look at the DX8's aluminum trim buttons:
Click to enlarge and note the aluminum switch replacements for the DX6i's known hazardous, ultra-cheap trim buttons,  Horizon Hobby/Spektrum is begging to be sued, they are the most negligent company I've ever seen in operation.
I urge users to send their DX6i's, or any other Spectrum radio with plastic trim buttons, back to the company and demand replacement with the safe aluminum buttons.  Since I know Spektrum will go into hiding like they always do when confronted with a myriad of safety problems, I'll post a "how to" fix tutorial shortly to help avoid an accident.

If you use one of these Spektrum radios, consider your fleet grounded until Spektrum corrects this potentially lethal flaw and caused injury to you, or worse, a friend or a family member due to known-defective flight controls.

Picture Tutorial:

Thursday, August 11, 2011

Quick take: Blade mCP X Flight Review

Update:  The Z8RC design mods bring the mCPX to A+.  Without them, the mCP X grade stands at F.

Winds have pushed me inside.  This flight review will be different than most as I am only an advanced novice when in comes to flying RC helo's, but I think there is value in this kind of review too.  
So far, this helicopter experience has been painful.  The copter is reasonably crash resistant, with one exception: the feathering shaft which bends in mild tussles that wouldn't phase an mCX.
My suspicions of this build-quality defect were confirmed when I visited the official Horizon mCPX page and the usual sales video has been replaced with a feathering shaft repair video.  Additionally I found a product bulletin (my local hobby store was unaware) grounding these helicopters until a dangerous rotor head defect is fixed.  I don't know if the new head is stronger and better protects the spindle, but obviously they both provide and replace the feathering shaft in the repair video so that is clearly part of the recall.
I am comfortable replacing and connecting these delicate parts, but the vast majority of buyers need will want a professional to do the work.  The provided Horizon Hobby "solution" (mailing out new heads and feathering spindles) is obviously unacceptable and results in an unusable purchase and thus a 100% loss for most consumers.
The package includes both a charge and an AC adapter,
better than other Blade buys that omit a charger with a wall plug.
Two batteries are included in the box.  The 250mAh battery
connector is non-standard and includes one cord adapter.
 More on flight characteristics, and the rest of the grades, after I receive a safe rotor head...

Overall Grade: F
Systemic quality defect with no acceptable solution.

Tuesday, August 9, 2011

E-Flite mCX "Tandem Rescue" Flight Review

Update:  Downgraded to F for poor quality.  Became unflyable after a few hours use with no crashes.


I got the opportunity to pick up a brand new E-Flite mCX Tandem Rescue Chinook for $39 bucks.  The price seemed a tad steep for a beginner coax, but what the heck, I know plenty of people who would love to play with such a fun little giant helo in exchange for a chain restaurant dinner--and I'm one of them.

After a little web surfing, I was a bit shocked to find an original price tag of $179 on this baby.  I mean, sure, it's a double-mCX which one could logically extrapolate to requiring twice as much money, or maybe more.  But come on, with a name like "Tandem Rescue" and the look and feel of a toy (albeit a pretty cool toy), I'm thinking more like $29 (great deal) to around $49 (pricey) would be a more logical range for a package like this.

That said, after you collect your jaw from the floor and walk away from the cash register with your new double Blade micro heli, this copter is really pretty neat.

Yes it is "just a coaxial" (or maybe it's a cocoaxial), and yes, it is even easier to fly in many ways than the monkey-compatible Blade mCX, but the design does have some unique capabilities compared to a standard mCX. For example, there is no need for a pitch servo, forward and backward movement is generated by varying the front/back tandem rotors relative RPM, much like yaw is controlled by varying the speed top/bottom rotors relative RPM.   This exaggerates the forward tilt of the ship as it breaks ground to go rescue drowning crickets.  Stopping forward motion is similarly cool, as you can hustle along - then slam on the brakes into a "flared," nose-high landing.  Not necessarily the easiest maneuver to execute perfectly, even though the basic coax skills are not challenging.

Another trait unique to the tandem arrangement is the ability to pirouette around just one set of rotors, or rotate about the middle of the helicopter.   And it is also a bit more challenging to align the longitudinal axis than a simple Blade mCX, since two rotors and some chosen pivot point are involved.

Adding interest, and perhaps utility as a basic trainer, is the counter-rotating prop wash which seems less problematic in general, at least as it affects the helo.  A single axis Blade mCX can get pretty beat-up in its own wash as it hovers low to the ground, and that wash increases as the mini-tornado builds over time, often shooting the micro out to one side.  The Chinook's prop wash tends to cancel itself over time; you experience more buffet but less wash-induced random directional motion. 

Other random benefits:  Two sets of rotors also build substantially more lifting power than an mCX. The helo has lots of flashing and steady LED beacons and position lights, making it a breeze to fly in total darkness.
But can it float?
All this adds up to a helicopter that is even easier to learn fly than a Blade mCX, and that is really saying something.  It also adds a certain level of increased interest and larger scale to a simple mCX.  As a basic RC orientation trainer, learning to push the stick this way when things go that way, the tandem mCX is hard to beat.

Some drawbacks are the bigger 1-cell battery requirement, and that fat battery's inability to fit into a typical 1S charger.  A one-battery-at-a-time charger with A/C adapter (finally) is included.  The helo will only run for about a minute using a more standard 150mAH 1 cell micro Lipo.

Another drawback is complexity.  And sure enough, mine broke without explanation or anything even resembling crash damage.  For some reason that I can't seem to solve, my helo can no longer pitch forward by increasing the tail rotor speed.   Going backwards (fast) is no problem.  Oddly, all the elevator trim and sub-trim in the world has no effect on this malfunction, almost like the tail rotor simply can't spin any faster for some inexplicable reason.  Changing the CG doesn't help either.  Bummer.  Unusable after 2 hours of solid fun.  $19.50/hr  ...seems steep.

Appearance: B
Neat - for a coax.

Flight Performance: B-
Certainly no aerobatic xtreme machine, but basic RC training potential is exceptional.

Build Quality/Durability: F
Toast after 2 hours.

Value:  D
I lucked out and picked one up for $39.  $179?  Good luck, E-Flite.

Overall Grade:  C-
Fun little excursion.  More child friendly than most.  Too complex and flimsy.

Wednesday, August 3, 2011

Z8RC Ultra Micro/Nano Speed Trials

The challenge: 
Fly between two light poles as fast as possible in level flight.  Flat speed to be derived by counting video frames.

The Field (in Order of Video Appearance):

Parkzone UM Pole Cat powerd by 1S Turnigy 138mAh 20C 
E-Flite UMX Sbach 342 powered by 2S E-Flight 120mAh 20C

Hobbyzone Champ powered by 1S Turnigy 138mAh 20C
E-Flite UMX Beast powered by 2S E-Flight 120mAh 20C
  
Nano Corsair powered by 3S Thunder Power G4 v2 350mAh 20C

The Race:
The hat-camera work isn't the best, but it'll do:

Click on the video to go to youtube and see the annotations

The Results: 
The Beast and the Pole Cat should be considered tied (within the margin of error) when sorted by time, but certainly not when sorted by $Seconds.  $Seconds = ($ * Seconds).  

I gave the Champ a $10 credit for its toy RTF radio.  The Nano Corsair price includes a 3S 350mAh battery and Optima 6 Rx.

By Time
Pole 3
Pol1e
Secs
Aircraft
Cells
Ch
Paid (BNF)
$Secs
14.40
12.93
1.47
Nano Corsair
3
6
$129.00
$189.63
30.62
27.80
2.82
Sbach 342
2
4
$169.00
$476.58
8.13
3.93
4.20
Beast
2
4
$169.00
$709.80
11.20
6.93
4.27
Pole Cat
1
4
$99.00
$422.73
57.90
52.13
5.77
Champ
1
3
$79.00
$455.83








By Dollar-Seconds
Pole 3
Pole 1
Secs
Aircraft
Cells
Ch
Paid (BNF)
$Secs
14.40
12.93
1.47
Nano Corsair
3
6
$129.00
$189.63
11.20
6.93
4.27
Pole Cat
1
4
$99.00
$422.73
57.90
52.13
5.77
Champ
1
3
$79.00
$455.83
30.62
27.80
2.82
Sbach 342
2
4
$169.00
$476.58
8.13
3.93
4.20
Beast
2
4
$169.00
$709.80
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