Monday, August 1, 2011

BlitzRCWorks Nano F4U Corsair Flight Review

Banana Hobby's Nano F4U Corsair in front of Parkzone's UM F4U (aka Jiggy)
$69 PNP
Manufacturers Spec:
- Foam: EPO
- Wingspan: 21.5 inch
- Length: 17 inch
- Flying Weight: 6.3 oz
- Drive System: Brushless OutRunner 2350KV Motor
- Propeller: 3 Paddles
- Speed Controller: 12A Brushless ESC
- Servo: 4X 2.5g high speed micro servos
- Battery: 7.4V 450mAh 25C Li-Polymer
Measured:
- Wingspan: 21.75"
- Length: 17.25" (prop nut to tail tip)
- Approx Wing Area (WA): 92 sq in
- Wing Loading (WL): 13.1 oz/sq ft
- Wing Cube Loading (WCL): 16.4
- Flying Weight including Optima 6ch Rx:  8.4 oz w/450 mAh 2s battery
- Motor & ESC work on 2-cell or 3-cell (7.4/11.1V)
Price paid: $69.99
On the ground:

I bought the PNP version of the Nano.  It comes as a complete fuselage and a complete wing.  All of the accessories, like the prop, landing gear, and tail wheel are pre-installed. The box holds a 450mAh 2s LiPo battery, an extra 3-blade scale prop, and a single wing screw.  Total parts count: 5.  Awesome.
The plane comes in two, completely RTF pieces with an extra prop and a 450 mAh 2-cell
The foam quality (as far as foamies go) is simply outstanding.
It feels significantly stronger than Z foam or Aerocell.  The surface has
a pliable but hard rubbery-plasticy feel too it.  You can stick Scotch
tape to the painted foam surface and easily remove it without
marring the paint.  The airfoil cross section wing feels beefy.
The cowl houses a brushless motor and is made of hard plastic
that is noticeably more solid than even the full size Parkzone Corsair.
The overall build quality of the Nano Corsair absolutely
trounces the Parkzone UM Corsair.
Putting the plane together consists of inserting your Rx in the nose accessed through the wing opening, plugging in the standard servo plugs, and attaching the wing under the fuselage with a single screw. The resulting build is stronger than any foamie I've seen to date, as the EPO foam is more like rubbery plastic then traditional foam. The level of detail is also the best I've seen on any foam RC model of any size.

Total build time is about 5 minutes. 4 minutes of that 5 is inspecting and thinking. This is an RTF-style build, not an ARF-style model. In fact, you can buy the Nano as a 2.4GHz 6ch RTF for $25 more. So while it is technically a PNP, it is not a PNP in the vain of something like the full size Parkzone Corsair or Select Scale Super Cub Rx-ready genre, as those require a much higher level of assembly to get in the air. This is a true RTF package, minus your choice of drop-in Rx. A PNP in the strictly literal sense.

The only faster builds are the typical, fully assembled micros, but those are no where near the same strength and quality of the Nano, which exceeds the foam quality and strength of the most expensive full size foamies on the market. This is one tough midget.

A very nice looking plastic radial and 3-blade prop give the model a well finished look.
Details set the Nano apart in a sea of lousy quality micros.
The rubber tires have raised lettering, the cowl flares with hard plastic
cowl flaps,and the tail wheel detail looks scale and is surprisingly sturdy
but it does not steer with rudder movement.  The plane comes with
sub-micro servos embedded in the wings.
21.5" vs. 15.9" span.  The finishes look simiilar here but are quite different.  
The Nano on the left has a high gloss tough rubbery feel (there was oxidation
in the gloss which melts to a wet-look sheen with a quick blanch from a heat
gun).  The PZ UM Corsair has a painted satin finish that is marred too easily.
Once "assembled," the battery compartment is accessed through the cockpit, which does double-duty as a well disguised lift-up battery hatch.  I added a folded Scotch tape tab behind the canopy for easier grip and removal.  A small magnet holds the hatch securely in place.  The only other mod I did was to snip off the sharp stick antenna behind the cockpit.  It looks nice, but it porcupines your palm every time you grab the plane naturally.

One reason the plane is tough is it's unusually thick, molded semi-symmetrical airfoil.  My suspicion is that the plane's relatively heavy weight demands a fat, high-lift airfoil.  An 8.4 oz RTF may not sound like much, but with a mean wing chord of only 4.25", the plane only has about 92 sq in of wing area to rest upon.  That works out to a whopping 13 oz wing loading, and a WCL of just over 16!  That is very heavy for a backyard flier; perfect for an air racer.  Yikes!  This could be interesting.

The Nano's first flight is right around the corner.   ...hold me.

In the air:

Flight testing is complete, and wow.  Wow, for a lot of reasons.  The first wow, is how underpowered the Nano is with the stock 2S battery.  The plane is flyable on the stock 2S, but barely.  You'll need a long runway and a takeoff that looks so scale you can hum the entire opening to Baa Baa Black Sheep before you are able to make a turn out.
Before blame is laid, a few interesting factoids:

First, I bought my Nano from Banana Hobby.  I know they get mixed reviews on the popular RC boards, but I also know the popular rc groups are nothing but a dishonest sham so that mostly Horizon employees can covertly and illegally libel and disparage other models and brands.

I've never had anything but great experiences with the lower cost outfits like Banana Hobby and Hobby King.  To the contrary, they generally sell higher quality stuff that is Made-in-the-Same-China but at much lower prices.  But in the case of the Nano Corsair, something a little more strange happens...

In the model's instructions, the text calls for a 3S battery and never even mentions 2S.  Hmmm, did Banana substitute a 2S to save a little money, I wondered?  After all, I electected to add $10 for a battery, since none is include in the base PNP price.  But upon closer inspection, the Nano comes from "FLYFLY HOBBY" in China, this is written on the tire sidewalls (see detail shot above) and surprise, it is also printed inside the 2S Lipo's clear casing.  So Banana is in the clear on this one.  FLYFLY is the one that underpowered the Nano, even though their own the instructions (or are they?) call for a 3S battery.  In fact, Banana Hobby is to be commended for allowing the customer to opt out of the stock 2S--and buyers of this little bird should absolutely do so.

My first flight was on 2S.  The plane barely accelerated, so much so that I aborted the takeoff.  To my suprise, the plane got airborne anyway at a slower speed than I expected for the wing loading and WCL.  I had already pulled th e power, so I plunked it back down and decided to wait on a 3S (= the delay in posting my flight review).  On 2S, the plane is difficult to fly unless you are blessed with a very large, very flat, very obstacle free venue.

What a difference a cell makes.  Given the difficulty I had on 2S, I elected to try a fairly small 3S.  But boy, I had my doubts as to if the Nano was going to work out.  The only bit of encouragement was how easily the plane flew for that tiny glimpse after my botched abort.  I was intrigued enough to press.

Since I was no longer technically stock, I decided to test not only 2S vs 3S, but also the sweet looking 3-blade vs a 2-blade.  Frankly, I thought I would need every oz of thrust I could muster to fix this plane.  A GWS HD 6x3 2-blade on 3S was noticeably stronger than the 3-paddle.  In fact, the plane wanted to pull out of my hands straight vertical, estimated T:W of about 1.2 to 1.    Ouuuuu, now we are talking.
GWS 6x3 2-blade on a Great Planes 4mm collet
The stock ESC is rated to 12A, which should be big time overkill for a 6x3 although I still have not metered it.  The big ESC is another clue that 3S was always the intent.  $15 poorer (not to mention $10 blown on the first batt--which I'm hoping will fit nicely in my Jenny soon) I headed off to explore this mornings calm winds.


Simply put, the Nano is sensational on 3S.  I think you'll agree it looks fabulous piercing the air.  In the following video my hat-cam isn't perfect, and I left the zoom too wide, but it is 720p so it should be enough to get a feel for of the Nano Corsair's flight characteristics. There was a little prop resonance during takeoff, but no issues in the air--maybe I'll try a stiffer APC 6x3 or 6x4 next.

The maiden video follows, and again, unlike every other maiden flight video on youtube, this one really is my first flight with the Nano.  A few disclaimers: the race track I'm flying has a purpose, as I entered the Nano in my Speed Trials thread, soon to follow.  I have no V telemetry hooked up to the Optima 6 inside the Nano, out of pure laziness, so I wanted to fly out the battery to get an accurate flight time.  I dead sticked the micro Corsair at a little over 6 minutes--not too bad for a 350 mAh 3S.
The Nano really flies like a 40" class plane, with the speed to match.  The downside is that it needs a lot of room for a micro and has some wing loading to support.  The upside, aside from pure flying enjoyment, is price and toughness.

The Nano Corsair is effortlessly fast and carves graceful lines through loop and roll aerobatics, just like a true warbird.  Rudder effectiveness is about perfect, deflection swings the nose but without the nose-down coupling that impairs Jiggy.  Aileron efectiveness is just right, the roll rate is very energetic but well controlled.  Elevator is effective and not prone to overshoot.

I was worried about the high wing loading, but the Nano proves that a great fundamental design can overcome simple numbers.  The semi-symmetrical wing airfoil is very fat for the chord, and quickly produces copious lift.  You definitely need to hold a few extra knots for Mom, but not as much as you might predict from the pure numbers, and the plane feels light on its feet as soon as flying airspeed whooooshes by--it is pretty nimble and responsive.  The combination of speed, grace, power, and agility seems very fitting indeed.  Unlike Jiggy, this tiny warbird wears the 440 mph, twin-radial F4U Corsair nameplate with pride.

Flying fun aside, this package has a few flaws.  It is advertised to work on 2S--yeah, uhm--don't do that.  The scale prop (spare included) looks great but is thrust deficient, even when compared to a decent 3-blade--so don't do that either, and especially not on 2S.  The main gear is stout and scale with genuine rubber tread tires, but the equally nifty rubber tailwheel is not steerable.  It's actually not that big a deal on takeoff, as rudder control is very quick to follow full power, but landing rolls end in a question mark.  An attractive alternative is to remove the mains, hand launch, and belly-land on soft grass.  If you attempt to fly on 2S, definitely go gear-less.

Lastly, it seems worth mentioning some of the micro appeal (e.g. flying in smaller spaces) might be negated by the speed and power of this little steely-eyed killer.  The flip side is a price so much lower than planes with similar speed and performance that the Nano creates it's own solid niche.

Appearance: A
Better scale details than full sized foam Corsairs; single color is hard to orient.

Flight Performance: A
Speed, grace and power from a micro?  Cool!!  Give yourself plenty of room.

Build Quality/Durability: A-
Flexible, rubbery feel; doesn't mar or ding; toughest foam I've seen to date.

Value:  B-
$69 + $15 (battery) is better than usual Ultra Micro ripoffs.  Needs Rx.

Overall Grade:  A 
Needs 3S and 2-blade HD prop; near-perfect warbird experience that flies big