The World Models P-40 Warhawk .46 ARF Review

And now, for something completely different: A P-40 Warhawk in Royal Air Force colors, hand-painted camo and retracts which rotate up and in like the real thing! Do prepare yourselves, chaps. Ralph Squillace has the word on this wondrous World Models warbird!

Splash

Introduction


Wingspan:57" (1450mm)
Wing area:564 sq. in. (36.4 sq. dm)
Flying weight:6.3 lbs. (2.86kg)
Length:49" (1.24m)
Wing loading:25.7 oz/sq. ft. (728.6g/9 sq. dm)
Speed range:
Control surface servos as tested:Cirrus CS601BB standard
Other servos as tested:Hobbico "Command" low-profile analog retract servo (HCAM0160); Futaba S3003 standard for throttle control (FUTM0031)
Transmitter as tested:Futaba 6EX six-channel FASST (FUTK6900)
Receiver as tested:Futaba R606FS (discontinued)
Receiver battery as tested:HydriMax 6V 2000mAh Ni-Mh (HCAM6350)
Engine as tested:O.S. .46 AX ABL (OSMG0547)
Fuel as tested:Byron Fuels 15% nitro for general aviation
Propeller as tested:Master Airscrew G/F Series 11x7 on initial flight; 11x6 on subsequent flight
Manufacturer:The World Models
Available from:AirBorne Models, LLC, 2403 Research Drive, Livermore, CA 94550 USA
Suggested retail price (USD):$229.99
Catalog number:A079S

I think my latent interest in World War II aircraft started when I was in or near the third grade and cemented when I began flying R/C. I recall a marvelous book with spectacular artwork of these planes in action. There was a gullwinged Corsair taking off from an aircraft carrier and a Mustang locked in battle with a German plane; to me, the name evoked the Ford automobile and as I would learn later, correctly so since Ford did in fact name their Mustang after the fighter plane.

One of those illustrations really stuck out in my mind: Picture flipping through such a picture book as this and coming face-to-face for the first time with a snarling, shark-mouthed Curtiss P-40 Warhawk. From that day forward, that face came to represent my favorite WWII aircraft paint scheme of all time. To me, the thought of heading into battle with that intimidating face painted on my engine cowl was inspiring, to say the least.

Fast forward to the present day, when a full-page ad for The World Models P-40 Warhawk in the August 2009 edition of Model Aviation practically leapt off the magazine at me. There was the obligatory shark's mouth on the nose (not to mention preinstalled rotating retracts which worked like the full-scale plane) but the model was in RAF colors!

Turns out The World Models did their homework. Introduced by the Curtiss-Wright Corporation and built at their main plant in Buffalo, New York starting in 1938, the Curtiss P-40 single-seat fighter and ground attack aircraft did in fact see action with both the RAF and Soviet air forces. In their service, it was known not as the Warhawk but as the very North American-sounding "Tomahawk," at least where the P-40B and P-40C were concerned. The equally American-sounding "Kittyhawk" was applied to the P-40D and later models. The term "Warhawk" was the name the United States Army Air Corps adopted for all variations.

By the way: Feel free to credit the RAF for the shark's mouth motif. It was in fact the No. 112 Squadron which first adopted the motif after a similar treatment by the Luftwaffe on some of their twin-engined Messerschmitt Bf 110 fighters. The motif was later adapted and made famous by the Flying Tigers, the 1st American Volunteer Group of the Chinese Air Force between 1941 and 1942.

While AirBorne does sell The World Models and The Wings Maker models and accessories through hobby shops, it's possible for consumers to order models and a full range of replacement parts directly through AirBorne Models, including parts for discontinued models.

Read on as we get in-depth with a model which represents a rich chapter in the history of military aviation.

Kit Contents

Your new The World Models P-40 Warhawk .46 features:

  • Fully sheeted fuselage
  • Preinstalled control surfaces with pinned metal hinges
  • Preinstalled and adjusted landing gear which rotate 90 degrees up and in like the prototype
  • Full hardware package with individually bagged and numbered parts
  • Decal sheet
  • Hand-airbrushed camouflage
  • Spinner
  • Detailed pilot figure
  • Prepainted fiberglass cowl with transparent two-piece trim template
  • Trimmed and painted canopy
  • Thin double-sided tape to aid in canopy installation

Here's what you'll need to complete your The World Models P-40 Warhawk. Since this model is intended for use by intermediate to advanced pilots, it is presumed that the modeler has most of the following on hand and the assembly manual further presumes previous ARF assembly experience:

  • Aircraft radio with five or more channels
  • Five standard servos
  • Low-profile retract servo
  • Standard 6" servo Y-harness if the ailerons will be operated from a single channel
  • Two (three if a Y-harness isn't used) standard 6" servo extensions for connecting ailerons and retracts to the receiver
  • Receiver battery of sufficient capacity and voltage to properly operate the retracts
  • .46 two-stroke aircraft engine or .70 - .90 four-stroke
  • Fuel of the proper blend for your engine
  • Fuel filler valve (TWM PL8110030, Great Planes GPMQ4160 or equivalent)
  • Propeller suitable for your engine
  • Cyanoacrylate glue
  • Two-part epoxy (I prefer the 30-minute variety since it sets so strong)
  • X-Acto #11 hobby knife or equivalent
  • Dremel high-speed rotary tool or equivalent with cutoff wheel and grinding stone
  • Electric handheld drill or drill press for drilling the engine mounts
  • Pin vise
  • Fuel tubing
  • Basic hand tools such as screwdrivers, metric hex wrenches, etc.
  • Basic field equipment such as a battery, electric starter, electric ignitor, etc.

Let's begin!

Assembly

Wing

I was very impressed with the P-40. All of the covering was tight, there was no damage to any of the components and all of them had a high-quality feel to them. Instead of either printing the camo scheme or using covering material which sometimes works loose over time and fuel exposure, The World Models' craftsmen airbrush the camo by hand, giving the model a very scale-like appearance. Several of my club's members have TWM models and they swear by them rather than at them and no wonder: They not only fly beautifully (this model is no exception as we'll see later), but replacement parts are a phone call or e-mail away to AirBorne Models if your local hobby shop doesn't stock the brand.

As with most ARF models, the assembly action starts with joining the wing halves, installing the servos and landing gear. In the case of the The World Models P-40 (yes, there are two "thes" in this case), the beefy looking retracts which rotate up and under the wing like the real deal are already installed. What I didn't see were the aileron servo mounting panels which are usually taped in place for shipping. A quick peek inside the hardware bag, numbered to correspond with the step number in the manual, revealed panels of a type I'd never seen before.

You see, these servo panels are not the usual plywood panels with hardwood mounting blocks epoxied in place but are instead beautifully molded in one piece in glass-filled nylon and covered with matching gray covering. Speaking of the covering, this was the first ARF I'd ever done which came out of the box with virtually no wrinkles. I say "virtually" because the only wrinkles I spotted were a couple of small ones underneath an aileron. One minor quibble regarding the servo mounts: There are no pilot holes in the mounts, thereby requiring you to mark and drill pilot holes. You'll need a long, small diameter drill to do this properly; I had standard length drills which worked OK for the top holes but made drilling the bottom holes tricky due to interference from the plate itself. A too-small drill bit I was using for the pilot holes broke off flush; it's now a permanent part of the plane.

Continuing on, the aileron servos placed into service were Cirrus CS601BB standard servos with their ball bearing-supported output shafts provided for a previous review by my friend Mike Greenshields at Global Hobby. Global claims that they are among the strongest standard servos on the market and among the most affordable; they had no trouble making an aerobatic .60 do its thing before its untimely demise due to a failed elevator linkage. I've been waiting for an opportunity such as this to uuse these little powerhouses once more.

As I generally do with all my models, I substituted Du-Bro #693 socket head servo screws throughout; a standard bag of 24 screws will do an entire airplane without fear of stripping a soft phillips or JIS screw.

"Fishing lines" for the aileron leads are pre-installed, but you might encounter a problem with the lines being unintentionally glued deep in the wing. Both of mine required persuasion, but don't worry. The woven nylon lead is plenty tough and will eventually break loose.

Normally, this would be the point where you'd install the ailerons. The World Models has taken care of this for you with all control surfaces preinstalled with pinned metal hinges. I applaud The World Models for this extra bit of quality. Not only does this save assembly time, but you also get the added security and smoothness of operation provided by pinned hinges.

You will, of course, need to add the pushrods and control horns and here's where things got just a bit dicey.

The ailerons don't use control horns, but rather some very beefy torque rods on a triangular base. It'll be obvious to you when you look at the hardware bag, less so when you look at the manual with its very small drawings and sometimes blurry photos. The manual seems to presume that the builder has previous ARF experience; given the level of skill required to fly the model, this level of experience is a given, but just be careful when reading through each step no matter what your level happens to be. The World Models is kind enough to provide pilot holes on the undersurface of the ailerons...but the holes don't quite line up with those in the torque rods. Compounding the problem was the wedge profile of the ailerons themselves; it was very difficult to line up the screws with the backing plate. Even the triangle shape itself adds problems. The shape is more isosceles than right triangle, so you have double the fun lining up the holes. I discovered that gently reaming out the screw holes on the torque rods made alignment much easier.

The pushrods require that you first screw on TWM's tough-looking nylon clevises and then bend and trim the pushrod where it meets the servo arm. Clip-on straps (referred to as "strapers" in the manual) secure the pushrod to the servo arm while precut pieces of fuel tubing provide an extra measure of safety. This sort of setup is, in my opinion, far superior to the usual practice of "ez-connects" secured by a knurled setscrew and a dab of threadlocking compound.

You're instructed to epoxy the wing halves together after first dry-fitting them with the massive hardwood dihedral joiner. It's a huge affair and fit almost perfectly; it was just a little bit loose and there are no guide pegs on the wing halves to keep them in alignment. I troweled on some thirty-minute epoxy to the entire joiner and one half of the wing, joined the halves together and used a small spring-loaded clamp to keep the leading edge aligned. Some wide masking tape secured the top and bottom of the trailing edge. A bit of alcohol on an old sock removed the little bit of excess which oozed from the joints. Then, it was simply a matter of roughly one hour of set time for a strong, perfectly aligned wing.

A quick hookup of the aileron leads to the Y-harness and then to my receiver showed that my initial setting of the pushrods was a tad off, requiring only that I readjust the clevises and one of the servo arms.

Finally, the part I'd been dreading needed completion, namely that of the Hobbico Command low-profile retract servo. I say that given previous experience with mechanical retracts. It fit just fine in the somewhat oversized mounting area, but be warned that there is a lot of lateral space on either side of that servo, so take extra care to make sure it's centered before you cinch it down.

The manual wasn't much help in determining the servo control arm requirements; some measuring and experimentation revealed that the best possible candidate for the job was the preinstalled circular arm. I used some bulk Great Planes ez-connectors I had on hand in lieu of the screw-on connectors provided (I simply don't trust these sorts of connectors; sorry, TWM) and I secured both with the permanent one-way metal disk as opposed to the nylon retainer. Both preinstalled pushrods needed only to have their ends bent upward to meet the connectors, but I had to make a 90-degree bend as opposed to the 45-degree bend the illustration suggests.

I should note something of some importance at this juncture. Per my discussion with Mr. Chan at the AMA convention as I'll outline in the next section, the pushrods should have no bend in them at all. This makes perfect sense; straight pushrods will make the job of assuring that the gear lock fully much easier than if they were bent. In any event, turning the servo by hand moved the retracts smoothly; would it work just as well under power?

Oh, yes indeed.

I plugged the servo into channel five of the FASST receiver, fired up Hobbico's magnificent Futaba 6EX FASST transmitter, plugged in the flight battery and crossed my fingers.

Perfection. I let out a whoop of joy with each and every cycle of the retracts with each cycle fully locking in both positions. It was so much fun that I almost hated to disconnect everything!

That, my friends, is a far cry from two other models I've had with mechanical retracts, neither of which ever worked properly. These retracts are truly a thing of beauty, raising and lowering fully without the slightest hint of binding. You'll notice that the instructions will tell you in their final step to iron on two precut patches of covering on the undersurface of the wing to hide the bellcrank access holes for fine tuning the operation of the retracts. TWM has already done this for you and should you ever need to access the bellcrank, replacement patches are provided in the hardware bag.

It's here I feel the need to jump ahead to the end of the book, as it were.

While the retracts work well on the bench, there is a serious Achilles' heel to be found. The turrets on which the bellcranks pivot are barely held in place by either adhesive or wood. As you'll read later, the gentlest of touchdowns resulted in the partial collapse of the landing gear and a scraped cowl. Upon further investigation, both bellcrank turrets had snapped off, resulting in the collapse.

What I wound up doing was to reinstall both turrets with a generous amount of 30-minute epoxy. One of the turrets was later reinforced with a small piece of 1/4 by 3/8" basswood which I trimmed to fit beneath the turret with the help of a Dremel.

I also feel the need to give serious kudos where kudos are due.

My nephew Jeremy and I had the good fortune to attend the 2010 AMA convention in Ontario, California. As I'd pointed out earlier, it was there we had the equally good fortune to meet Fai Chan face-to-face at AirBorne Models' extremely busy booth. Mr. Chan took us aside and we spent the next 20 minutes poring over a new P-40 wing he'd brought down all the way from Livermore per our e-mail correspondence.

What I learned was simple yet very important. The "hammers" at the end of the pushrods which lock the gear in the down position should be as snug as possible. In other words, the pushrod must be extended fully. Mine were in fact fully extended, but the gentle touchdown was still enough to push back on the bellcranks and break them loose.

I leave it up to you, dear modeler, to reinforce the turrets on your own P-40 in whatever way you see fit. Personally, I would remove the screws holding the bellcranks and trim some basswood stock to fit snugly beneath the turrets. Once trimmed, install your wood reinforcements with some 30-minute epoxy; drill down through the turret with a small drill mounted in a pin vise to make a pilot hole in the reinforcement once the epoxy sets. That was how I'd repaired on of the turrets on my test model after a faulty repair on my part.

Regardless of how you finally resolve the issue, my suggestion would be to reinforce the mounts before your maiden flight in order to avoid the mishap I suffered. You should also rest assured that Mr. Chan and I have discussed the possibility of the factory either updating the mounts on subsequent production runs or even providing a factory-designed reinforcement kit as part of a technical bulletin.

Get ready for a bit of extra but very necessary work in some very cramped quarters; there isn't much room to manuever inside those bellcrank access hatches, believe me.

On to the fuselage!

Tail

Thankfully, there is little to report here. Assembly is straightforward and first requires you to remove the trim from around the rear of the fuselage which covers the slots for the horizontal stabilzer. You'll have to remove a couple of wooden shipping plugs as well.

The horizontal stabilizer goes in first. Like the ailerons, both the horizontal and vertical stabs come with the elevator and rudder pre-installed with pinned metal hinges. A quick tug on both showed they were in to stay. This also meant that the stabilizer and elevator did not have to be assembled on the airplane; they simply slide in place from the rear.

In order to properly align the horizontal stabilizer, you must first install the wing. The bolts and washers you'll need are in the number 17 bag which of course corresponds with step 17.

I used the time-honored alignment method of epoxying the stab in place; after careful measurement between the aileron and elevator per the manual, I used a Sharpie marker to lightly draw guide lines on top of the stab along its attaching point. After mixing up a batch of 30-minute epoxy, I troweled some on the exposed wood on both the top and bottom of the stabilizer. Yes, The World Models has taken the time to neatly remove the covering for you where the epoxy needs to go!

When the stabilizer was realigned, some ordinary rubbing alcohol removed the Sharpie ink and extra epoxy. A precut and pretrimmed plug then goes into place immediately behind the stabilizer, sealing the installation slot and adding some more attachment area for the tail. On went some more epoxy to the tail's pretrimmed mounting areas. The fit here is a bit snug, but not enough to raise concern. It's actually to your advantage; the tail wasn't able to "float" around inside the slots and cause alignment problems. Again, some rubbing alcohol on a paper towel served to clean up the excess epoxy while a bead of CA tacked down an ever so lighly warped bit of the fuselage which serves as the upper right hand arm of the stabilizer mounting slot.

The tailwheel goes on next; no surprises here. Well, just one: Whereas TWM has provided predrilled alignment holes for the torque rods, no holes are provided for the tailwheel mounting bracket. No real problem, just be careful to align it properly when you drill the pilot holes. A prebent U-shaped aluminum bracket attaches the tailwheel lever to the underside of the rudder. As an added precaution, use a little bit of blue threadlocker to secure the little 2.5mm nut to the bolt which holds the bracket in place.

Ah, but the holes for the torque rods are drilled in both elevator halves and the rudder. Same types of "tripod" torque rods in each numbered bag that we first encountered in the aileron installation. Better still, they align properly with the holes! Save yourself a lot of frustration: Gently ream the holes on the rods and their backing plates to avoid the possibility of stripping the screws. Otherwise, you are going to have one heck of a time driving those screws home and aligning them with the backing plates. I used a 5/64 drill which took off enough material to make attaching everything easier, but not so much to cause the screws to fit too loosely.

We move on to installation of the control surface pushrods. TWM recommends the use of their clevis wrench to more easily install their strong but somewhat hard-to-install clevises. You'll install the two elevator pushrods with their curved ends first from the inside of the fuselage; the straight and slightly longer rudder pushrod can go in from either direction. Remember to slip one of the supplied short lengths of fuel tubing over each pushrod to later serve as safety retainers for the clevises...and don't attach the clevises to the pushrods just yet. You'll only have to unattach and adjust them later when you install the servos and the recommended pushrod lengths are simply too long. These lengths don't make much sense anyway; they only protrude just so far from the fuselage.

Engine

Installation of the strong, four-piece, adjustable nylon-filled engine mount is next. The manual suggests (and rightly so) that the enclosed attaching bolts be secured with blue threadlocking compound. However, I delayed that step until I fitted the engine just in case I'd have to adjust the mounts inward or outward.

Once the mounts are in place, it's on to step 11, namely the fuel tank. Nothing much to report here other than my intentional omission of the filler line (and the need for a second clunk line) since I was going to use a Great Planes filler valve. The manual itself suggests the use of TWM's optional fuel filler valve, so if you use such a valve, omit the filler tube. Although it isn't mentioned, you may wish to attach some untrimmed lengths of fuel line to the inlet and outlet tubes. This is much easier to do with the engine out since the tank's neck doesn't extend all the way into the firewall.

Step 12, oddly enough, is the preparation of the throttle servo which didn't make the slightest bit of sense. Here's where the manual kind of blew it. The servo trays aren't called for until step 16...after you've installed the cowl. Found this out the hard way, so I'll jump ahead slightly and tell you here and now to prepare the servo and install the trays per step 16. This will allow you to set the proper throw for the throttle after the engine goes in; you won't be able to see the carburetor after the cowl is in place.

One of the truly thoughtful touches on this model is the engine alignment. Instead of the cylinder being reclined at a 90-degree angle, TWM chose to rotate the engine downward about 30 degrees more, resulting in a crankshaft centered with the thrust line and a muffler aligned directly below. The very happy result of this is the use of the stock muffler in a fully enclosed cowl; no need for an expensive Pitts muffler and an excessively trimmed cowl to clear the pipes. You'll see what I mean in step 13; it shows the installation of a two-stroke with its stock muffler. Bravo, The World Models!

As for the engine: I had hoped to secure a .90 four-stroke for this review, but none were available. Undaunted, I put my lightly used O.S. 46 AX two-stroke to use. This state-of-the-art two-stroke had recently seen duty in a .70 four-stroke-sized biplane I'd won at a club raffle and fitted with this engine, but which suffered damage to its expensive fiberglass fuselage and to its wings due to a crash immediately after takeoff. The model was new, but the engine had been used and it showed some scuffed cooling fins on the cylinder head. The crash busted off one of those fins since the model came plowing into dirt along on its right side, so on went a brand-new cylinder head.

Back to step 13: The front crankshaft bearing/bushing needs to be placed 120mm from the firewall, or pretty much at the end of the mounts.

No matter how hard I try, I can never seem to drill the holes in an engine mount perfectly straight with a hand drill; I am going to invest in a drill press soon. If you have one, use it.

Still, I didn't do too bad. The bolts slipped in with a minimum of fuss upon a test fitting. Don't forget the lines to the tank before you attach the engine! Much easier to do with the engine off.

You'll have to drill a hole in the firewall in the approximate indicated location in order to route the throttle pushrod and tube.

Oh, joy. There's a fuel tank on the other side. I was relieved to see that the hole I drilled didn't come close to the tank, but when I routed the tube and pushrod out the indicated spot on the internal bulkhead behind the tank and with the engine temporarily in place, the pushrod binded badly. Relocating the tube directly next to the tank alleviated the problem and, as I'd learn later, didn't create any problems since the throttle servo tray installed later has plenty of leeway to mount the servo. Heck, there's enough room for three servos in that tray, so again, finding the optimum mounting location is a cinch.

I like testing my engines at this point, so on went the prop and a spare spinner. Bit of fuel in the tank through the filler valve, ignitor on, starter at the ready...zoom! The O.S. with its new cylinder head started right up and pulled like a freight train as I opened the throttle via the pushrod. The day was rather warm and it didn't take long for the fuselage's covering to relax in places. I took the opportunity to acclimate both the wing assembly and fuselage to the outdoors and while the covering relaxed on the fuselage as I indicated, it relaxed in only a couple of small places on the wing. Some minor touch-up with my covering iron shrunk and glued everything right back in place.

Trimming the cowl is next and I have to tell you, TWM's transparent two-piece template is one of the greatest innovations in the history of ARF models. Simply slip the template in place of the cowl and trace the openings for the head, mixture screw and exhaust with a Sharpie marker. Cut the openings out of the template, slip it over the cowl, trace the openings and get busy with your Dremel and grinding stone. You'll likely have to hog out the opening for the head more than you'd first think necessary (not to mention the possibility of having to notch the very front of the cowl at the engine opening in order to clear the crank) but after the fiberglass dust had settled, I had the most perfectly aligned openings I'd ever done on a cowl. Once you're satisfied with the alignment of the cowl with the fuselage (and yes, all of the paint lines up perfectly between cowl and fuselage, including the camo), use your pin vise to drill pilot holes through the predrilled holes in the cowl and through the fuselage. The mounting screws are held in place with the aid of ingenious silicone grommets; thread the grommets onto the screws before cinching them in place. Just don't do what I did and drop one since there are no spares. I was in the process of moving and sure enough, I dropped a screw and grommet which, after some searching on the floor, likely bounced onto one of the moving boxes next to my work area. Until it turns up, a slightly smaller cowl mounting screw from the parts bin was placed into service.

TWM suggests the use of their fuel filler (PL8110030, not included) which goes inside the "mouth" of the cowl's shark graphic. As I pointed out, I opted to use a Great Planes filler I had on hand (GPMQ4160). Big mistake on my part: I used the Dremel to grind out an opening and it was too large! Salvation came in the guise of a soft plastic CD case; the center hub of the lid was just the right size for the filler's inlet and although the filler rotates a bit since it isn't fully cinched down on the outside of the cowl (and I didn't want to put any washer where it would be visible), it's holding on well with negligible weight gain.

Canopy and Radio Installation

Before I basically completed the model with the installation of the pilot, canopy, fuselage servo trays and radio system, I opted to install the prop and spinner at this point since the cowl installation photos show the prop and spinner installed. The spinner is one of the nicest plastic spinners I've ever seen and is backed with a strong nylon backing plate. If you use the same engine as I did, you'll have to open the hole in the backing plate with a 1/4" drill bit; it will then fit perfectly over that or any standard 1/4-inch crankshaft. Once the prop was bolted down, I fully expected to have to spend several frustrating minutes trying to get the cone to line up with the backing plate, but no. It slipped right on with the mounting posts aligning perfectly with the screw holes. I may have to convince the local hobby shop to start carrying The World Models spinners.

If you do install the propeller at this point, make sure you have whatever extension you may have for your high-end needle adjustment. As many do, I used an old, cheap allen wrench of the type that comes with wheel collars and other accessories. To be able to get an allen driver through the crank opening and back to the setscrew, I first had to remove the cowl mounting screws. Once the extension was in, I put everything back in place. Your installation may vary depending on your engine.

Step 15 is next with the simple installation of the pilot bust, dashboard decal and canopy. The pilot figure is exquisitely painted and attaches firmly with a strip of double-sided foam tape in the shape of the bottom of the bust.

The dashboard decal is too large to fit the dashboard and must be trimmed. Not a problem. What is a problem is the choice of graphics. Since this is a stand-off, semi-scale model, little touches like the pilot figure and dash add to the static realism.

So why does the compass graphic show the outline of a modern jet plane?

This in turn brings me to my only real gripe at this point and that's regarding the decal sheet.

I'd elected to apply the decals since, once again, there's no indication of exactly when the decals go on in the first place. The RAF squadron markings, roundels and tri-colors are present and accounted for. The rest of the sheet is a bit strange.

There are numerous "ON OFF" and "PUSH PULL" decals (pushing and pulling what, exactly?), a slew of The World Models roundels and website addresses, two decals proclaiming the plane to be an ARF, two more which advertise ToughLon covering, two stylized civilian-looking registration numbers, random numbers and "P-40" in black, blocky sans serif lettering and my personal favorites, decals which simply (and perhaps with unintentional humor) denote this model as an "Airplane" with an "A" in the approximate shape of a jet.

TWM's own F-4U Corsair .46 comes with no fewer than four historically accurate decal sheets denoting any of four actual Corsairs. I would have loved to have seen a decal sheet for the iconic Flying Tigers version; the plane's existing colors seem to match fine. If nothing else, it would have been wonderful if the more unusual or promotional decals were replaced with reproduced stencils of the type seen on any warbird. Doing so would have certainly saved space on the sheet and made cutting them out far easier, not to mention adding a bit more scale "oomph" to the finished product.

I'd suggested this very thing to Fai Chan in an e-mail I'd sent to tell him of my progress thus far. Fai got back to me in less than 24 hours with the promise to suggest revisions to the decal sheet directly to The World Models! Based on my previous experience with Fai, don't be too surprised to see revised decals in future production runs.

Once applied, the RAF decals looked great. They're pressure sensitive, so I used a spray bottle filled with plain water which allowed me to remove the decals if need be and to align them just right. Research showed that the RAF often put a numeric or alphanumeric ID number behind the squadron markings and another semi-scale British warbird of mine has such a designation. Instead of the stylized registration number, I used the more accurate sans serif mixed numbers and numbered it as 5736. Either that or 1428 since the numbers were printed on the sheet as "14285736" with no "9."

As for the "GM" squadron designation, there really was such a designation in World War II. According to one website, it denoted the No. 74 Squadron RAF, a fighter squadron which likely used the P-40 in battle, although my research didn't turn up any specifics. The "D" in this case would denote an individual aircraft.

Step 16 is the final installation of the remaining radio equipment. It begins with the assembly of TWM's coupler which allows the two elevator pushrods to be activated as one. I took a moment here to hook up the servos to the receiver and center the trims before I installed the servos into their trays; you'll need to mark where the pushrods attach to the servo arms, then bend and trim them to fit and to accept the "straper" retainers. All straightfoward stuff and any misalignment of the control surfaces at this point can be adjusted at the clevises.

The receiver and onboard battery are retained by another very thoughtful item. This is the first ARF I've ever assembles which provides a foam block for retaining the electronics! I'd purchased a sheet of 1/4" foam as I usually do when assembling one of these models, but I wound up returning it.

Slots for the receiver and battery are precut; simply pop them out, insert the receiver and battery and tuck the whole works into the front of the fuselage behind the fuel tank. Since the receiver's sockets are hidden after the receiver is installed, make sure you plug a standard 6" servo extension to your aileron and retract channels and run them up through the top of the opening. Some 3M Transpore surgical tape (sold in most hobby shops as hinging tape) secured the antenna leads to the fuselage. Complete the installation with a power switch; I opted for a JR heavy duty switch (JRPA001) without the external charging jack since the model would be spending most of its time on the ground with the wing removed, giving me easy access to the switch's charging pigtail.

Completion

Steps 17 and 18 are the home stretch! I went back for that number 17 hardware bag I'd used earlier to temporarily attach the wing in order to align the horizontal stabilizer. I attached the retract and aileron servos in order to test them with the wing in place and then I attached the wing with the M4x35mm socket head screws and M4 washers. A 3x12mm screw comes in that bag for attaching the rear of the beautifully crafted fiberglass air scoop to the bottom of the fuselage; the front is held in place by a spring-loaded pin.

Except for the final CG check, I now had a finished model.

What a beauty it was, too.

Despite the fact that the prototype was built in 1938, the model had a sleek, modern look like that of a present-day sport plane. Think "Edge 540 in olive drab camo" and you'll get a good idea of my impression of the finished product.

A quick check of the radio system showed that all was A-OK including the retracts. So, on to the control throw setup at step 19. The elevator is set at 20mm, rudder at 30mm and the ailerons at 10mm; this setting would later be reduced to a more manageable 6mm. My too-short servo arms on the ailerons had to stretch a bit to get that 10mm throw, but they did so with no binding or interference and better still after I reduced the throws.

Center of gravity is 80mm behind the LE of the wing, or at the first wing spar as is the case with many ARF models. My Great Planes CG Machine balancer showed the P-40 to be rather nose-heavy. Experimenting with the relocation of the battery resulted in a wildly tail-heavy setup, so it was back to the original configuration.

It only took two 1/4-ounce Great Planes lead weights to balance the model, but installing the weights in the fuselage proved difficult; there isn't much room to get one's fingers through the bulkhead and into the fuselage. The solution came in the mounting of the weights between the blind nuts used to retain the wing. After removing the wing for the umpteenth time, I employed a couple of servo screws from the ol' parts bin secured the weights in place with no fear of the tape coming loose. On went the wing and air scoop, back on the CG Machine...success! The P-40 was balanced and ready to go!

Flying

Basics

Although the P-40 was ready to rock in October, the maiden flight wouldn't take place until December. I managed to get the model assembled one day before my wife and I moved into our new place.

Fast forwarding to just after Christmas found me at the Coachella Valley Radio Control Club outside Thermal, California with my unofficial "support crew." Helping out yet again was club president Dan Metz and videographer Ken Alan of Kaminsky Productions of Cathedral City, California.

Ken started snapping away with both his digital SLR and broadcast minicam while I installed the wing and belly pan. Dan and I checked the CG and lateral balance. The CG was on the nose, but the right wing was a bit heavy. Two 1/4 ounce weights on the left wingtip solved the problem.

A quick double-check of the landing gear and control surfaces showed them to be nice and level. In went a tank of fuel and on came the engine. The idle was too fast, so Dan temporarily trimmed it back via the transmitter into a more manageable speed; there was no need to remove the wing in order to set the linkage, at least for the time being.

Taking Off and Landing

I carried the P-40 to the flight line; Dan would fly the maiden flight. After a few taxis up and down the runway, it was time for takeoff. Dan pointed the model into the wind and brought up the throttle. The rather prodigious torque of the O.S. 46 AX swung the nose left and toward the dirt, but Dan managed to keep the plane on track for a perfect takeoff.

The first thing Dan noticed was the aileron rate. Lots and lots of aileron; too much in fact. It took a very little amount of stick to bank the wing, but the P-40 remained predictable, if twitchy.

After a couple of easy laps around the pattern to set the trims (which needed little setting) and to help with getting acclimated with the rather sensitive ailerons, Dan decided to "open 'er up and let 'er rip."

Aerobatics/Special Flight Performance

As Dan called out his intended manuevers, I relayed the info back to Ken on the video camera who told me later that he had no trouble keeping up.

And no wonder.

The P-40 was speeding along without the slighest sign of instability at around 70 mph (110km/h) at roughly 1/3 throttle, with plenty more speed on tap. I should note that my subsequent flight with an 11x6 prop in place of the 11x7 used in the test allowed for a bit more throttle and a happier, higher revving engine. Dan set up for a low-altitude, high-speed pass which he pulled off with no trouble at all thanks to the combination of the P-40's build quality and the accuracy of the Futaba FASST radio. Around he came for a second pass, this time with the gear up and sure enough, the pass was just as nice and possibly even more impressive with the clean undercarriage. Dan pulled out of the second pass with a victory roll with a rate which rivaled a pattern or 3D plane because of the excessive throws. In fact, it was one of the nicest rolls I'd ever seen from any warbird.

From there, it was inverted flight. The P-40 maintained inverted flight with practically no down elevator needed to maintain altitude. Now it was time to really get nuts with Cuban Eights, half Cubans and a huge, magnificent loop seen at the conclusion of the flight video. It was clear that Dan was having fun, but it was time to land, refuel and turn our attention to the ailerons and throttle linkage. A quick pass to insure the gear was down and around the P-40 came from base to final.

That's when trouble began.

As you'll recall from the section on the wing assembly and landing gear servo installation, the P-40 literally greased the runway on what would have been an easily controlled three-point landing. Even so, that gentle touchdown caused both landing gear to partially collapse when the bellcranks broke loose. The collapse was enough to allow the propeller to grind off its tips on the asphalt before the engine stalled. The model skidded a considerable distance down the runway before coming to a stop. I'm pleased to report that the damage was merely cosmetic as indicated by the photos; the underside of the cowl took the brunt of the impact, resulting in little more than scraped paint.

Personal commitments meant that it would be just after the new year before I could go in and repair the bellcranks. Once I did, it was finally my turn to try out the Warhawk, so off the club field I went.

I wasted no time in resetting the aileron throws; the throttle issue had been settled the night before. Dan's primary complaint during the maiden flight was about how twitchy the ailerons were. I'd brought up the issue to Mr. Chan at the AMA convention and he agreed that the recommended 10mm throws were far too much. I reset the throws to 6mm and kept the exponential at 30%.

The plane felt really light on the tailwheel and the elevator trim was a bit off on my first flight; as I throttled up, the nose tried to come down, so I shut down the engine, carried it back to the pits, electronically trimmed the elevator which was visibly pointing down and restarted the engine.

Much, much better.

I'd decided ahead of time to leave the gear extended for the first flight, giving me a chance to concentrate more on the model's overall flight characteristics and less on the "eye candy" of a clean undercarriage.

The flight characteristics were, in a word, stunning.

After the P-40 lifted off the runway on a right-left takeoff and was high enough for an initial right turn, I was immediately at home; the preflight "butterflies" simply disappeared and didn't return for the remanider of the flight. All it needed was a bit of down elevator and left aileron trim.

Once trimmed, the plane handled as if it were on the proverbial rails and displayed no twitch whatsoever. The control was smooth, predictable and well, just plain fun. The Windsor 11x6 scimitar prop turned out to be a good choice; the P-40 was still scorchingly fast when I opened the throttle, but the engine revved a bit higher at cruising speed with none of the sputtering I'd heard on the maiden flight. After about a minute, I was convinced that I was at the controls of what may have been one of the best-flying planes of my experience since I became involved in the hobby.

Lining up for a landing proved to be a bit of a small issue; this plane really wants to fly. Despite its size and heft, the Warhawk apparently has very light wing loading. It took me three attempts to bring it down; what worked best was to go out long on final and bring it in slow and shallow. I may try flaperon mixing at a future date.

On the very gentle touchdown...boom. One collapsed landing gear.

I was amazed to say the least since I thought the issue had been solved. As luck would have it, the fault was mine. All that held that bellcrank in place was the little bit of CA I'd used to secure it while the epoxy set. The other side held up just fine with plenty of epoxy securing it in place.

Turns out I missed getting any of the epoxy on the turret, to tell the truth. Naturally, my second attempt to repair the problem was addressed with considerably more care. This was the side I wound up reinforcing with basswood as I'd indicated earlier. As of this writing, both sides are repaired, the gear locks firmly in both positions and no amount of reasonable pressure I exerted on the turrets would break them loose. I'm convinced that the repairs will hold up well in service, but stay tuned to the talk page for updates.

Is This For a Beginner?

Despite the ease of assembly, surprisingly gentle flight characteristics as determined by the use of a computer radio and overall quality of the model, it is not intended for beginners. Though the Warhawk's flight characteristics are more like those of a low-winged sport model as opposed to a warbird, it has none of the self-righting characteristics of a trainer. While intermediate and advanced pilots will throughly enjoy wringing it out, beginners are advised to look elsewhere in The World Models' catalog.

Flight Video/Photo Gallery

Downloads

Conclusion

I used to read any and every automotive-related magazine I could get my hands on as a teenager and flying the P-40 reminded me of a review of the Mercedes-Benz 450SEC back around 1978 written for Car and Driver by the late, great British automotive journalist L.J.K. Setright. I'll never forget the rather aristocratic headline he wrote: "It goes as it should." Setright was right on the money. Anyone who's ever done time behind the wheel of a Mercedes or other premium automobile knows that such a car does what's asked of it with very little drama as compared to lesser automobiles. So it is with the The World Models P-40 Warhawk .46. It simply "goes as it should," responding to one's inputs with the aplomb of a thoroughbred and building pilot confidence with each passing minute. You get all the fun of a sport plane and none of the sometimes tricky flying characteristics sometimes evident in a WWII warbird. In short, The World Models has a winner. Build quality is excellent, documentation is clear and concise despite a few minor mistakes and final assembly is a breeze. The innovative cowl cutting template is indicative of the care which went into the design of this model and greatly simplified the most difficult step in any ARF. Other decal schemes which match up with the iconic shark's mouth graphics would be a welcome addition and may actually come to pass thanks to this review.

Despite the issue with the retracts, I still give the P-40 a "two thumbs up." It's just too good a model. The preinstalled units are a marvelous touch and one which resulted in retracts which worked flawlessly on the bench, but they absolutely, positively need attention before one even considers flying this model for the first time. Reinforcing the bellcrank turrets, while inconvenient, is not impossible and within the skill level of any average modeler. Doing so beforehand will be a lot easier before they're broken off.

There is a lot to like about the The World Models P-40 Warhawk. Among them:

  • Stellar flight characteristics
  • Excellent hardware package, all prepackaged in numbered bags corresponding to the step number in the manual
  • Excellent craftsmanship
  • Pre-installed three-piece hinges add strength as well as durability
  • Very good documentation
  • The cowl cutting template is a stroke of genius
  • Molded one-piece nylon-filled aileron servo mounts add a high-dollar touch of class
  • Horizontal stabilizer comes with an exposed adhesive area, eliminating the possibility of damage to the wood while removing covering
  • Airbrushed camo gives an air of realism as does the beautifully rendered fiberglass engine cowl
  • Outstanding customer support

As for the minuses:

  • Weak landing gear bellcrank turrets will break off on even a gentle first landing if not reinforced first
  • Aileron pushrods proved difficult to install
  • Clevises are difficult to thread onto the pushrods
  • A longer-than-usual drill bit is required to drill holes in the aileron servo mounts
  • Most of the decal sheet is nearly useless
  • Too much space on either side of the retract servo
  • Some documentation errors, especially in regards to aileron throw, throttle servo installation and landing gear pushrod-to-servo mounting

On behalf of everyone here at RCGroups.com, thanks for reading and enjoy your new P-40 Warhawk from The World Models.

See you at the field!

Last edited by Angela H; Mar 05, 2010 at 05:30 PM..
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Mar 07, 2010, 03:44 PM
Ldm
Ldm
Ldm
Ldm's Avatar
Being a P40 collector I was intrigued by the plane when first introduced .
My hesitation was in the fact that i would need to do many ARF bash mods to get the plane up to my liking .
When I looked at the plane I was looking at the same mods as I did to my very inexpensive Balsa Products P40 -that was
1)add Top Flight P40 gear pods , add front full length air scoope , add bottom cowl vents , cut counter balances into tail area , reduce alerons and simply add split flaps --add rear window with acetate and add the robart 615 retracts knowing the plane was light enought to handle them all completed on my Balsa Product 66" P40 , cost of model $119 .

So my conclusion with the World P40 was that the starting price was too high for the work needed to get the plane looking and flying in a reliabale manner and looking like a P40 .
I am really surprised that world models in my opinion missed the mark really far with this P40 when you see great intro from China with the VQ P40 and Black Horse P40 and CMP 73" P40 , all great flyers and priced in the same class as the World MOdels P40
Mar 07, 2010, 09:55 PM
We shall serve the Lord
kingsflyer's Avatar
Ralph, I like the model just the way it is. It may not rate 100% with the scale model crowd, but it is readily identified as a P-40 and it looks like it flies great. I hope you will be adding more flying video clips in the coming weeks. Hope you can show us some takeoffs and landings as well as some closeups of the gear cycling through their full travel.
McD
Latest blog entry: LEDs on my T-28
Mar 08, 2010, 12:46 AM
Pronoun trouble...
DismayingObservation's Avatar
Thread OP
Thanks, Mac.

I had all sorts of cool video on hand as well as a very detailed and fun presentation in Windows Movie Maker, but it turns out that my videographer shot it at the highest possible resolution. I had to keep the clips short so that I could get Windows Movie Maker to render them. I tried everything possible to get that session to render down; I finally had to split it in two and shorten the halves a lot more than I would have otherwise liked.

Definitely want to post video of the retracts; I'll review the DVD and post something here soon. I'm sure I cycled them for Ken to shoot, but between a late review and the technical issues, I wanted to get something here on the boards as quickly as possible. I agree that it could use work in the scale detail department - the simulated window was something I had planned to mention but neglected to do as part of the concern with the lack of scale detail on the decal sheet - but as a sport scale or stand-off scale plane, it's a winner. It's kind of a "P-40ish" sport plane as opposed to a full-on scale warbird.

I'm honestly looking forward to flying it again
Mar 08, 2010, 09:21 AM
Why yes, I am an R/C addict!
flyrcehelis's Avatar
Wow, looks good.
Mar 08, 2010, 11:33 AM
Pro Bro # 2398
GassPasser's Avatar
nice , but overpriced in my opinion.
Mar 08, 2010, 07:32 PM
Gilbert, AZ
chalmrast's Avatar
Having what I would call "alot" of experience with rotating retracts, I have to ask how any force from the landing could be imparted to the bell cranks?

Do these retracts not "lock" into position? If the bell cranks broke, that means forces were also exerted on the servo!

Also, for mechanical rotating retracts, may I suggest a retract servo with a little more "oomph?" The JR791 is the only way to go IMHO.

World Models planes are great flyers, and parts are easy to get if you need them.... but they are indeed a little pricey!

Chad
Mar 08, 2010, 10:01 PM
Pronoun trouble...
DismayingObservation's Avatar
Thread OP
The retracts did indeed fully lock down and since the servo's in the center of the wing, I couldn't see how motion from the servo might have done it.

Given the food for thought you just gave me, normal wing flex on touchdown might have broken them loose. That actually makes more sense even though the direction of the breaks indicated they'd been pushed back. Nevertheless, very little is holding those turrets in place; very gentle force of any kind would have snapped them off.

Good point regarding price. It is unquestionably a bit pricey compared to similar planes and I considered mentioning it in the review. I thought that the overall flight characteristics would overcome the issue.
Mar 08, 2010, 10:13 PM
Gilbert, AZ
chalmrast's Avatar
I have a World Models .46 Miss America. It's in need of some repair after I stalled it turning into the wind on landing approach.

On 5S and an E-flite Power 46 it flew really nice. Barely weighed 6lbs!
Mar 08, 2010, 10:19 PM
Ldm
Ldm
Ldm
Ldm's Avatar
Ralph , sorry , the post cut me off , I said I am glad that you have found a good flyer in the Wolrd models p40 , good luck with the plane and if you add some fun mods please psot them
Mar 08, 2010, 10:49 PM
Auctung! P-40!
P40D's Avatar
PMDrive1061,
Very nice P40. I was wondering how well it would fly with a GS40 engine?
since I already have that engine. thanks.
Mar 09, 2010, 08:58 PM
"On the Wing"
paulo810's Avatar
I usually complain to myself because the video files accompanying these articles are too huge. This one is too short! I would have liked to see more in flight action of this beautiful plane.
Mar 10, 2010, 02:09 AM
Pronoun trouble...
DismayingObservation's Avatar
Thread OP
Quote:
Originally Posted by P40D
PMDrive1061,
Very nice P40. I was wondering how well it would fly with a GS40 engine?
since I already have that engine. thanks.
Good question...I think that it would in fact fly OK with a .40, but that would be a question I'd ask the distributor. Mr. Chan has been extremely helpful to me in the past couple of years and he really know his products. FWIW, it flies like it has very light wing loading, but it feels heavy when you give it the old heave-ho. As a side note, I have a homemade "simple plastic airplane design" plane with an old Thunder Tiger .40 which I got from a user on these boards. That thing weighs a ton, but doggoned if it doesn't fly great.

As for the video...no one's more frustrated than I. I had a heck of a presentation put together which really showcased this model, but the raw footage was shot in HD and my poor little laptop was simply incapable of rendering mixdowns any longer than this.

On the up side, there is a heck of a lot of raw footage. I'm going to throw a few more little vignettes together and post them here.

Oh, and one of the club members has that same P-51! Man, what a sweetheart. Thing absolutely screams through the air.
Last edited by DismayingObservation; Mar 10, 2010 at 02:14 AM.
Mar 10, 2010, 02:13 AM
Pronoun trouble...
DismayingObservation's Avatar
Thread OP
Quote:
Originally Posted by Ldm
Ralph , sorry , the post cut me off , I said I am glad that you have found a good flyer in the Wolrd models p40 , good luck with the plane and if you add some fun mods please psot them
I sure will. Diggin' your P-40! That Flying Tigers color scheme and livery are just stunning.

There is a gentleman I often see on the weekends at one of the fields who actually flew the real deal stateside during the war. Guy is one terrific modeler, a brilliant conversationalist, a heck of a nice guy and I'll wager he's pushing 90. I told him of the problem I had with the retracts and he told me that was a very real problem on the full-scale plane! Art imitates life, after all.


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