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Introduction
ZERO! This one word would usually strike fear in the hearts of men. OK, well, maybe60 years ago, now most peoples' thoughts would be of those fragile planes usedby foolish young men in Kamikaze attacks. Certainly not an auspicious end toone of the war’s most numerous and revolutionary war bird designs. Nevertheless, its sleek lines and legendary status causes it to be one of the most recognizableaircraft to come out of the propeller-driven combat aircraft era. Designed by Jiro Horikoshi, who also designed several other Japanese aircraft both before and during World War II, theMitsubishi Navy Type “Zero” fighter incorporated both cutting edge and controversialdesign philosophies. While the aircraft was known to be unable to hold up tothe heavy firepower of allied aircraft, in experienced hands, however, it washighly maneuverable and very hard to catch in the gun sights of enemy aircraft.Its lack of self sealing fuel tanks and pilot protection (at least until thelate war versions) caused it to be relatively easy prey once allied tacticschanged and better aircraft appeared in the Pacific theatre (and experiencedJapanese pilots became very rare). The reason for the Zero's frailty was notmilitary apathy for the pilot or some sort of Bushido code, but simply apragmatic way of meeting stringent Navy requirements and compensating for therelatively low (by western standards) power output of the just over 900horsepower Sakae radial engine. Compared to the likes of the nearly 2,000 hp F4UCorsair it is amazing that the Zero had even a fighting chance. Every efforthad to be made to keep weight down to a minimum and keep aerodynamics clean.The results were a modestly powered aircraft with outstanding climb,maneuverability, and importantly, long range flight ability. While hopelesslyoutclassed by the end of the war, it remains a figurehead of the once greatJapanese military air power and a reminder of the horrors of Imperialism. Ok, I admit, I have a strong interest in Japanese aircraft. A couple of interestingreads I highly recommend for the curious would be SAMURAI!, a first hadaccount of flying the Zero by ace pilot Saburo Sakai,and Eagles of Mitsubishi: The Story of the Zero Fighter, by Jiro Horikoshi himself (a veryinteresting engineer's view of the design and development of the Zero). Butenough of the history lesson, on to the model.
The Power
Kyosho has produced such a really nice rendition of the infamous Zero for .40 to .50class glow engines that I just could not pass up the opportunity to convert itto electric power. When first conceiving the power setup for a glow to electric conversion, I usuallylook at several aspects of the model. Namely, wing area (which mostly helpsdictate cell count) and the model type (i.e. sport, aerobatic, scale, andetc.). From past experiences of mine and others, the general rule of thumb is that~.25 size glow planes (around 300-400 sq. inch wing area) generally use eightto 12-cell packs and .40 size planes (around 500-600 sq. in.) usually use 14 to16 -cells. .60 size planes can go upwards of 24 cell Nicad/NiMHpacks. Now that Lithium Polymers have entered the scene, one can basically replacethe word "cell" with "volts". Where the type of plane comes in is in motor/gearbox/prop selection. Sport/aerobaticplanes are usually best on geared setups while racer type planes may needlittle to no gearing. With this, I take into consideration prop selection aselectrics generally fly very well on high-pitch props on gearboxes. But if itis a 3D type plane, a large diameter, low pitch prop is usually better. Thereis no absolutely correct answer, which can lead to quite a bit of confusionwhen approaching a solution. Enter the electric flight prediction programs. Most motor manufacturers list recommendedmotor/prop/battery/gearing suggestions for different types of planes, butsoftware can be a great help to fine tune the power setup you will use toprovide the motivation your bird to will like the most. These include Moto-Calc (www.motocalc.com), Electricalc(www.slkelectronics.com/ecalc), or even a simplified web-based programcalled P-Calc (brantuas.com/ezcalc/dma.asp). Since the Zero is a .40 sized model, my goal was to use 14 to 16 cells as I wanted toleave the 14-cell option open in case the model came out too heavy for mytastes. Then there was the issue of determining what size propeller to use.Fortunately, the nice thing about electrics is that with the use of gearboxes,larger diameter props can be used than would be the case with glow engines.Larger props are also usually more efficient as well. Test fitting the pieces out of the box, I crudely measured that up to about a14" prop could be used before I would be in danger of plowing a groove inthe runway during take off. Not only that, since the real Zero had athree-bladed prop I wanted to see if I could find a suitable model prop of thesame type. Looking through the APC website, I found that they make a 13.5"by 13.4" three bladed prop. High pitch and a usable diameter, now thingswere getting interesting! Now continuing to work backwards, I had to find a motor/gearbox combo capable ofswinging such a prop on 14-16 cells at reasonable current, say 40 or so amps atfull thottle. Why 40 amps? Well that is usually whatmost types of sub-c and Lithium Polymer packs can handle without the cellvoltage being depressed by much or getting too hot (the battery pack may nothave much ventilation in the fuselage). It is also a common current rating withmany manufacturers’ motor controllers. This means that is isimportant to not choose a motor that is too small (unable to handle the continuouspower), or too big (i.e. too heavy). Running the chosen three-bladed propeller and various motor setups through thee-flight prediction program, the setupthat looked most promising was the Hacker B50-11L with 5.2:1 planetary gearbox.With that motor/prop/gearbox/16-cell battery combo, the current draw should bejust under 50 amps for some nearly 800 watts of power.
Next would be weight estimation. Kyosho lists the flying weight at about 6lb. Ofcourse, this is for glow powered versions. An electric version would probablycome in heavier. I could get a rough idea of the electric flyingweight by subtracting the weight of an engine (17 oz.), Fuel tank (2 oz.), andthrottle servo (2 oz.); 21 oz. total. Then, adding in the weight of themotor/gearbox (10 oz) and of course the battery pack (32 oz), a difference of21 oz. was obtained. This guesstimated the flying weight at 6lb. plus 21 oz.,or around 7.3 lb (3.3 kg). I would see later just how close this came to theactual flying weight.
The Kit
Two wing halves, the tail surfaces, cowl, and canopy. That pretty much sums up thebig bits of the ARF "kit". All evidence that assembling the planewould not take a lot of time. Also included were basically all the hardware(including wheels) that you would need to install everything, includingoptional landing gear doors for retractable landing gear.The overall colors looked pretty accurate for a late model zero (if fresh fromthe factory). In addition, two large decal sheets contained markings for threedifferent squadrons including that of the 203rd and 302nd Naval Air Groups(pictured on the box cover). Lots of other things are there to stick on as welllike various kill markings, stripes, labeling, and of course the Hinamarus (those big red "meatball" circlethings).
Wing construction consists of wood sheeted foam core with extra wood pieces locatedat strategic places for extra strength, wing joints, and landing gearmountings. The ailerons were pre-hinged as well with slots for the aileronservos and landing gear wells identifiable under the film covering. While therewere understandably a few wrinkles in the covering, they were easily removedwith the application of a heat-gun. The color division of the wing's upper andlower half was also quite good.
The real gems of the kit are the wonderfully detailed fiberglass fuselage and cowl! Solid but not overbuilt (plywoodbulkheads add support to the interior and provide servo mounts), the fuselagecontains details such as the wing fairings and accurate recessed panel lines(the details you would typically see in a scale plastic model, just much bigger).Color masking is very sharp and while some of the mold lines are visible, theyare small an unobtrusive. There even seemed to be a bit of right thrust builtinto the fuselage. I noticed a little bit of color separation at the mold linesof the cowl but some touch-up paint is an easy fix. Like the fuselage, it alsohas recessed panel lines along with machine gun recesses. In fact based on the cowland other details, it appears that Kyosho was attempting to make the A6M5cModel 52 (late war) version of the Zero. This is basically the last version of the A6M5produced, where in addition to having two 20mm cannons in the wings, these latewar types had one of the smaller caliber 7.7 mm machine guns mounted in thefuselage replaced by a 13.2mm machine gun. This was done in order to try tomore effectively combat the heavily armored American fighter planes and bombers(in some cases, cockpit armor plating and two extra wing mounted 13.2mm gunswere added as well). Because the 13.2mm machine gun was larger in size, itcreated the asymmetrical look to the cowl due to the larger hole needed for itsclearance. Lastly is the bi-lingual manual (Japanese-English) which features clear and logicalphotos and diagrams. Oh, yea, the English translations are pretty good as well.
The Construction
Gluing in the pre-hinged ailerons initiates the construction of the model.
Next is the landing gear setup. The kit also provides for fixed landing gear bymeans of a pre-made "plug" that fits into the wing. However, if youwish to use retractable landing gear, you simply cut away more of the wingcovering to reveal the wheel wells already cut out for you. While a little moretime consuming to setup, I simply could not resist the urge to install retractsinto my heavy metal fighter. Skipping a few steps in the manual, I decided toinstall the retract mechanisms before gluing the wing halves together as Ithought it would be more practical for installing the linkages.
For the retract setup, the kit is designed with the intent to use mechanical unitswith the retract servo in the wing's center. This is a very reliable and practicalsetup that did not take much time to install. The retract mechanism I used werethe Great Planes .40 sized mechanical units (part number GPMQ2910). A Futaba136G retract servo that I already had on hand serves nicely in this duty as itis a dedicated retract servo that has 180 degree of travel, 76 oz./in. oftorque, and most importantly moves slowly and semi-realistically.
Also included are plastic wheel well inserts. While these needed trimming andpainting, they prevent a hollowed look of the bare wheel well cut-outs. TopFlight Dove Gray spray paint was found to be a close match to the wing's lowersurface colors. However, the molding of the wheel inserts are not quite deepenough for the retract struts to allow the gears doors to lie completely flushwith the bottom of the wing. This, fortunately, was the only real issue I hadwith the kit.
For the two wing servos, metal geared versions of the HitecHS-85BB servos were used. Since they are rated for 40 oz ./in.of torque, they should have no problems moving the control surfaces despitetheir smaller size. Once the servos are mounted, molded plastic covers arepainted and screwed into place. All the control surface hinges are the thin CAtype for easy installation.
For the motor mounts, I used the stock glow engine rails with screw-down clampmounts (MPI) made for 05 sized electric motors. I temporarily mounted the cowland motor in order to properly center and drill the holes for the mountingrails. The instructions also show how to cut out the openings for the enginemuffler and cylinder head. It was sure nice to not have to do that! Once the wing is glued together it is mounted using the typical dowel supportedleading edge and wing screw/blind nut trailing edge mount. Next is thehorizontal tail which is glued into the fuselage slots. Once this is done, thetail wheel swivel must be installed. While not difficult, it did take somepatience as a small 3mm washer had to be soldered onto a thrust tube so as toprovide support. A basic 40 watt iron and rosin core solder worked fine for thetask.
With all the tail control surfaces mounted, the pushrods must be made with theincluded materials. The pushrods are wood dowels with metal rods attached tothe ends so each rod must be cut to length and bent and heat-shrinked to the slots in the wood dowels. I also dabbed abit of glue to everything before heat shrinking the entire affair. To determinethe exact lengths the rods, I first mounted the servos to the pre-installedplywood servo mounts.
On electric conversions, it is always interesting to discover where the battery packwill be located. Since the kit was not designed to carry such a large batterypack (or electric motor as well), you never quite know how or where it will beplaced until much of the building is done. With much of the airframe completedand most of the components mounted, I needed to determine the best location forthe 16-cell battery pack (and hope I could get it to fit where needed). Modelsof radial-engined aircraft can be a bit tricky inthis regard as they normally have very short noses. To get the balance correcton the model, part of the firewall had to be cut away in order to slide thebattery pack forward enough. This was done by drilling a dozen or so closely spacedpilot holes and then using a razor saw to cut out the rest. The firewall'sstrength was compromised only minimally and not of much concern since electricpower is by its very nature a low vibration method of propulsion. Once the holewas cut out, I then added a plywood plate to aid in support of the batterypack. While the battery pack will actually hang under the support plate inflight, it will mostly serve as a mount for the Velcro (tm) battery straps.
For the speed controller, the Castle Creations Phoenix 80 was used. This is a sensorless controller capable of handling a hefty 80 ampsat up to 16-cells (with BEC option up to 10 cells). The Zero's power setupwouldn't draw nearly that much current, but it is better to have an over-ratedESC than an under-rated one. Castle has updated the software to allow the userto program a whole host of options including startup speeds, motor timing, frequency,and even low voltage cut-off values (great for Lithium Polymer users). All this in a package weighing only 2.1 oz.
Probably the most time consuming part was that of painting the canopy. The Zero'sdistinctive greenhouse canopy is made up of many small window panes which arefaithfully re-created in the kit’s molded lexan version. This must be trimmed,masked, and painted (easy to say, takes a while to do, though). Tamiya IJN Green plastic model paint straight from a spraycan seemed to match the colors of the kit pretty well.A little patience paid off as the finished product came out quite nicely. I alsopainted the white control horns with a bottle version of the same color so theywouldn't be as noticeable.
For the elevator and rudder servos, I again used HitecHS-85MG ball bearing servos. They mounted perfectly into the smaller slots ofthe servo mounts. The receiver and UBEC battery eliminator regulator were velcroed to the insides of the fuselage. With the control surfaces connected and operational, what remained was the final powerplant installation. After mounting the fiberglass cowl with several small screws, it was time to mountthe prop and spinner. As planned, I used the APC 13.5 by 13.4 prop with amodified DuBro 3-bladed spinner painted a lightgunmetal color. With everything now mounted and seemingly flight ready, I had areally snazzy looking model. The next step was to test the power plant and seehow closely reality matches theory. 16-cells of Sanyo CP2400 cells discharging into the Hacker motor pulled around 47 amps,according to my trusty Whatmeter. This equated tosome 750 watts of input power. Very nice and pretty close to what was expected.Since the flying weight at this point was 7.4lb (3.4 kg.), I was still pullingjust over 100 watts/ lb. which is very good for a sport plane. Oh, and at fullthrottle it tried to pull the airframe out of my hands pretty good as well.
The last task was to apply the extensive number of stick-on decals to the model. Usingthe box art as a guide, I was able to place most of the decals. I chose to usethe 203rd NAG marking which I had found a similar photo on the internet. Therewere a few of the smaller details (like the tiny "No Step" Japanesetext on the wings) that required some additional references, but they arebarely noticeable at any rate.
The Flying
No more excuses. I could have spent a few more hours detailing the kit, but it is an aeroplane,which implies flying. So it was off to the field I went. The first flightattempt was done at an electric fly-in in front of a captive audience. Not agood idea for a first anything. Through a fault of my own, I failed to fullysecure the retract servo which upon take off caused the landing gear to becomeun-locked from their down position. The result was Zero skidding a few feet onthe runway just short of take-off with its suddenly self retractingundercarriage. No real damage was done, and after re-securing the retract servo, it was time for take two of the maidenflight Yet again in front of a captive audience (I guess I never learn). Thistime, however, the flight went much better. After one last range check andstart of the flight timer, full throttle was then applied. A little bit ofright rudder and she was airborne and climbing like a Zero should climb. Infact, I was quite surprised how quickly it took off (even considering that itwas a grass runway). It was quick and powerful. Any weight concern subsided asI quickly flipped the retract switch and watched the gear retract in a niceslow manner while still climbing steeply.
A few trim setting laps later (a little too much up-trim being the cause to the really quick take off), itwas time to test the stall characteristics. Quickly climbing up to about 50mistakes high, I pulled the throttle back and maintained level flight as thespeed bled off. To my delight, the stall was quite uneventful and resulted in asimple mush-like descent. No wing snapping tendency was noticed. With the recommended control throws, the Zero was very responsive. Loops, rolls (slow and fast), strafingruns, and even snaps were a snap. The motor/prop combo worked great and allowedfor easy part-throttle cruising. While not a racer, the model is pretty quick,quite easy to see, and can practically turn on a dime. In fact it handled sowell that I was instantly at ease with said aerobatics on the very firstflight. I also didn't notice much of a difference in trim with the gear raisedor lowered.
Landing the Zero is pretty straight forward. With the gear down, the model still retains speed well and acontrolled descent is easy to maintain. Don't expect it to float like atrainer, but it certainly doesn't fall out of the sky when the power is reducedeither. As with most larger war birds (especially withretracts) it is best to keep the speed up a little on landing and fly it to theground instead of trying to fly it really slow and stall it in. Even at lowspeeds, though, the elevator maintained very good control right down to touchdown. Banzai, baby! The electrified Kyosho Zero is a very nice flying model that any moderate to experienced pilot should haveno trouble handling. Aerobatic and nicely detailed, it also has great presencein the air and on the ground.
As you probably noticed, I'm really happy with how the model turned out. For additional details, I plan toadd a pilot figure and dummy exhaust stacks (among other things) to furtherenhance the look of the model.
Flying Videos
Conclusion
Hits:
Misses:
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Thread Tools |
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Nov 27, 2003, 06:31 AM
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#2 |
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Involuntary Beta Tester
Join Date: Jan 2002
Location: Frisco, TX
Posts: 8,016
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Very nice review and I was there to witness it's successful maiden flight and despite the weight it flys very easily and lands smoother than my Kyosho Spitfire with is about a 1/2 lb lighter. I believe the stall characteristics are better behaved. My Spit seems to drop a wing a little at times.
With the fiberglass fuselage there doesn't seem to be anyway to cut a battery hatch so you have to remove the wing to remove the batteries for charging. Looking at the photos of the battery install it might be a tough fit for the square shape of the a 8000 5s4p TP pack. 6100s should be an easy fit though. Hopefully, Fitz will be able to experiment with Lipos in the future. I'm looking forward to meeting Fitz's "Meatball" soon with my Kyosho Spit. Kelvin Last edited by kelvin; Nov 27, 2003 at 02:03 PM. |
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Nov 27, 2003, 11:00 AM
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#3 |
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SKI BUM
 
Join Date: Mar 2000
Location: Reno, NV, USA
Posts: 3,694
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Very nice review!
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Nov 28, 2003, 10:17 PM
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#4 |
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Big & Fast Pusher Jets
Join Date: Mar 2001
Location: Coeur d'Alene, Idaho, USA
Posts: 4
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Problem viewing video clips
I am unable to view video clips of the ZERO. Has something changed of is it just me?
Thanks, Loren |
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Nov 28, 2003, 10:49 PM
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#5 |
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No "R" !!!!!!!
Join Date: Jan 2000
Location: Where Spacemen Live (TX)
Posts: 1,009
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Thanks very much for the great ratings for the article.
I had meant to address the battery access issue, but since I was already way over schedual, I've left it to the one's own devices. I had thought of (a) making part of the cowel partially removeable (upper portion like Kyle's large Zero), or (b) cutting some type of access "door" in the fuselage to access the battery connector only for charging. The batteries would stay in the airplane. I like the idea of a door, but wanted it to look scalish. I've also thought about perhaps the cockpit area as well, but i think that would be too time consuming to implement. |
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Nov 29, 2003, 08:31 AM
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#6 |
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Registered User
Join Date: Oct 2003
Location: west michigan
Posts: 17
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thanks for the article
what a cool plane..as a 47 year old newbie in flying but sage veteran in rc cars....the name kyosho brings to mind clean design and quality.
this plane is wonderful....and the builder has done an outstanding job on it. looking forward to having one of my own.......as soon as im done with newbie crash into everything phase :}. and what nice video... A+ eef |
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Nov 29, 2003, 10:16 AM
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#7 |
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No "R" !!!!!!!
Join Date: Jan 2000
Location: Where Spacemen Live (TX)
Posts: 1,009
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Doh, I almost forgot. Thanks goes to Raymond Cervantez for being kind enough to provide digital copies of the flight video for the review.
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