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Model Rectifier Corporation Ultrafly P-40 ARF Review

Ultrafly Models visits the era of the Second World War with the Curtiss P40 Warhawk, the next model in a continuing line of well engineered foam planes.

Splash

Wingspan:36.6"
Wing Area:201.5 sq. in.
Weight:22.7 oz.
Length:31.7"
Wing Loading:16.22 oz/sq. ft.
Servos:Ultrafly ST-9
Transmitter:Multiplex EVO 9
Receiver:Mikro Designs SPF-5
Battery:Thunder Power 1320 3S Prolite
Motor:Ultrafly F/12/10 Brushless Motor
ESC:Ultrafly Athena 28 Brushless Speed Control
Manufacturer:Ultrafly
Available From:Model Rectifier Corporation and your local RC dealer
Price:$85.98

Introduction

Ultrafly Models has been making models ever since I returned to this great hobby after an eight year hiatus. The Hawk, the Sukhoi 27 and the Furious biplane have all seen service in my hangar, and I still have several of Ultrafly's other offerings awaiting building: the PC9, the F16 and a few more Hawks. Yes, they are that nice!

This P40 is an instantly recognizable plane, thanks to its garish grin. Every airplane I review here ends up adding to my knowledge of the real plane they are modeled after, and the P40 is no exception. Why is it we always associate the Warhawk with the Flying Tigers in Asia? Wikipedia explains:

The Curtiss P-40 was an American single-engine, single-seat, all-metal fighter and ground attack aircraft that first flew in 1938. It was used in great numbers in World War II. When production of the P-40 ceased, in November 1944, 13,738 had been built. They were used by the air forces of 28 nations and remained in front line service until the end of the war.

The P-40's lack of a two-stage supercharger made it inferior to Luftwaffe fighters in high-altitude combat and it was rarely used in operations in Northwest Europe. Between 1941 and 1944, however, the P-40 played a critical role with Allied air forces in five major theaters around the world: China, the Mediterranean, the Southeast Asia, the Southwest Pacific and Eastern Europe. The P-40's poor performance at high altitudes was not as critical in those theaters where its bomb load, durability, and good range were highly valued. In theaters where high-altitude performance was less important the P-40 proved an effective fighter. The P-40 offered the additional advantage of low cost, which kept it in production as a ground attack fighter long after it was obsolete in air superiority.

So THAT’S why!

It is also worth noting that Ultrafly is now distributed by Model Rectifier Corporation. A peek at their web site reveals quite a few new models from Ultrafly. From pusher jets to aerobatic models, foam to built up ply and balsa, Ultrafly has something for everyone, whatever his or her preference. Additionally, they are repackaging some of their "Legacy" kits as ARFs that come pre-covered and with servos installed. What this means to you and I is even less time at the building table and more time at the field flying. Do you prefer to cover your own model? Several of Ultrafly's foam planes, including this P40, can be purchased unpainted for the "Artistes" in our midst. And while you are selecting a plane, go ahead and grab an Athena speed controller, Ultrafly brushless motor and servos for it. There is a very good chance that they are all available at your local hobby shop. And if not, MRC's web site can indeed provide you with a one-stop shopping experience.

Kit Contents

The P40 arrived very well packed, with the fuselage halves and wing safely in their very own bubble wrap bags and the balance of the components in regular plastic bags.

The kits from Ultrafly are very complete. They typically contain several different "trees" of plastic parts to prevent you from having to make a visit to the hobby shop to pick up all of the miscellany that the average kit requires. From clevises to hatch retention devices to control surface horns, it is all there.

I was instantly drawn to the two large sheets of decals that blanket the bottom of the box. Ultrafly has made it possible for the builder to dress his plane in the liveries of many of the world's Air Forces.

My review Warhawk came equipped with a Ultrafly F12/10 Brushless Motor and an Athena 28 Amp ESC. I also received a trio of the Ultrafly 9 gram servos.

It can be a little difficult to locate the specifications on the Ultrafly motor and speed controller, as they have not updated their web site to reflect many of their latest kits and electronics offerings.

Kit Includes:

  • Pre-painted foam fuselage (2 pieces), wing, and tail feathers.
  • Plastic canopy, cockpit and cowl.
  • Two trees of plastic parts.
  • Landing gear and wheels.
  • Spinner.
  • Ply firewall and stick mount.
  • Hinges.
  • All pushrods, horns and clevises.
  • Fiberglass wing spar.
  • Two sheets of decals.
  • Illustrated instruction manual.
  • Velcro and complete hardware assortment.

Kit requires:

  • Motor.
  • Speed controller.
  • 3-4 Micro servos.
  • Two six inch aileron extensions.
  • 4-6 channel receiver.
  • Servo Y-adaptor (required if four channel receiver used).
  • 3S Lithium Battery, sized to appropriately match power system.
  • Propeller.

The kit also comes with a nice photo-illustrated MANUAL. USE IT! It is very nicely done. Though these kits from Ultrafly go together quite easily, I found out the hard way that you need to read the "fine print", even when it is in the form of a little picture!

Assembly

The P40 kit does not have very many pieces, and once you start assembling it, it goes very quickly. The kit comes with a bottle of special foam glue. You are also admonished at times to use CA and Epoxy. As usual, ensure you are using foam-safe CA or you will watch in sadness as the foam "burns" up in front of you. The manual does a very nice job of suggesting what type of glue to use for any given step.

You will need the typical tools for the assembly of this model. Make sure you have a fresh box of razor or Exacto blades. Anything less than a sharp blade will not cleanly cut the foam that this bird is composed of. It will crush or fracture it instead.

Wing

The wing is a one-piece design, so you won’t need to glue two halves together, which is often the case.

You will need to cut the two ailerons free and bevel their leading edges. I also dressed the trailing edge of the wing to square it up.

The leading edges of the ailerons need to be beveled. Its best to cut the hinge slots BEFORE you do this.

Once you have cut slots for the included hinges, DO NOT reach for your bottle of CA as you probably typically do when gluing CA style hinges in. Though the hinges that come with the kit look similar to CA style hinges, they are of a different composition. This is where I failed to read the "fine picture"! The manual clearly indicates that using the included foam glue is necessary to secure these hinges. I tried CA and could not figure out why it was not working ! Once I used the correct adhesive, the ailerons were properly secured.

The kit comes with a 780 mm fiberglass spar to give the wing some rigidity. It does not completely fill the slot cut into the bottom of the wing, so ensure you center it up, leaving the slots equally empty at the wing tips. The spar ends up being pre-loaded, due to the dihedral of the wing. Glue one half of it in and then patiently let the glue fully cure before trying to bend the other half into place.

There are precut recesses in the bottom of the wing for the aileron servos. The Ultrafly ST9 servos fit with only minor enlarging of the openings necessary. As I normally do, I used hot glue to secure them. You may need to use servo extensions, depending on the lengths of your servo leads. I cut a small pocket into the bottom of the wing for the extension connector and hot-glued the servo lead and connector in place. I normally use electrical tape to provide an insurance policy against the extension somehow coming unplugged. In this case. I was comfortable with the hot glue serving this purpose.

The white plastic tree has the control surface horns. I used a pin drill to create pilot holes for the two screws that secure the two piece horns together.

The white plastic tree also contains all of the connectors you will require to assemble the short pushrods that connect the servos to the control horns. I deviated from the manual just a wee bit, instead opting to use my handy Z-bend pliers for the control horn end of the pushrod. There are occasions in life where being short is good. These pushrods are among the shortest ones I have ever encountered in my kit building adventures. Suffice it to say, you will not experience any flex or twist on these aileron pushrods!

The only thing left to do to complete the wing is to attach a few of the black plastic pieces, used for wing attachment purposes.

Fuselage

Before gluing the two fuselage halves, there are a few important steps. Ultrafly provides several different options for mounting the motor. You can use a standard stick style mount or a firewall mount. And the firewall can be glued in two different positions, depending on what motor you are using. Measure twice and glue once or it will be time to order another fuselage. It is also necessary to make the penetrations for the rudder and elevator pushrods before gluing the two halves together. I used a bamboo skewer for this step, as the ones I have are approximately the same diameter as the pushrod outer sleeves.

Glue the two halves together with the recommended foam glue. I used Epoxy but I caution against the five or six minute variety, as there is a fairly large amount of area upon which you must spread the glue, and it may start setting up before you are ready.

There are several black plastic pieces that must be attached for wing and hatch retention purposes, and there are four small ABS plastic cowling mount squares that must be glued on.

It is also necessary to trim the cowl prior to attaching it. This involves not only trimming around the perimeter to get rid of the excess flashing but also cutting a large hole in the lower front of the cowl for motor cooling.

A pair of curved jaw scissors is invaluable for this type of trimming. Or, as an alternative, you can use a very sharp blade to repeatedly score the Lexan until it cleanly breaks.

While you have those scissors out, trim the canopy as well. I elected to use a plastic pilot I received from Keith Sparks, who is legendary on RCGroups for his production of all things plastic.

The canopy attaches to its base with glue, although I decided to use several strategically placed pieces of Blenderm tape to hold it in place. Doing so would permit me to regain access to the cockpit area to add more detail later should I desire.

Tail

The rudder and elevator halves must also be cut free from their respective stabilizers in the same manner as the ailerons, and ditto for the beveling of their leading edges. The two elevator halves must be joined together by using a elevator joiner rod. Be careful when drilling the pilot holes for this rod, as the elevator halves are not very thick.

Normally when gluing the tail feathers on, it is necessary to be very diligent in making sure everything is square and level in relation to the fuselage and wing. Ultrafly has taken a lot of the worry out of this process as the tail feathers have aligning pegs that fit into holes.

As the manual suggests, the most important thing is to make sure the elevator is level and the vertical stabilizer is, well, vertical, before the glue dries.

Radio and Motor Gear Installation

The fuselage contains a precut cavity for the two remaining servos to be installed. I again used hot glue, although the friction fit would alone would have probably held them in place. A little more hot glue was used to try and keep the excess servos leads neatly in place.

When inserting the two long metal pushrods for the rudder and elevator, I did not like the amount of friction I felt when trying to slide them by hand. Most micro servos cannot overcome too much restriction in pushrods that are too tight in their sleeves. It is important to make sure both ends of the outer sleeve are not pinched, oblong or out of round, possibly from from having been trimmed in length during installation. If the restriction is still excess, I like to use fine sand paper to dress the metal pushrods up to a shine and then coat them with a little graphite. The improvement is amazing.

I have used these little Mikro Designs five channel receivers in several models, and I am very impressed with their dependability. They are absolutely tiny and yet, so far, very glitch resistant.

The motor attaches to the firewall with the included screws. The F12/10 fits into the cutout on the front of the P40 very snugly. The motor is very nice looking, as it comes out of the packaging. I positioned the ESC as far forward as possible, for both CG and air-cooling purposes.

Completion

Now is the time to make sure that no little details were overlooked. Are all servo horns screws reinstalled? Is the Center of Gravity within the manufacturer’s recommended range (40-45 mm from the leading edge at the wing root)? Are the control surfaces set as recommended?

I decided to use the Thunder Power 1320 3S Pro-lite battery to power the P40. Though I have read in the corresponding build thread for this plane on RCGroups of many using 2100 sized packs, I decided to stick to the lighter 1320 for several reasons. Using a larger pack will make the targeted CG of 40-45 mm difficult to achieve, as the fuselage design does not permit the larger pack being inserted as far forward as it needs to go for proper balance. Also, I ran both the APC 10X7 Slow Flyer and the Master Airscrew 3 bladed 9X7 up on my wattmeter and both of them pulled around 17-18 amps, well within the 1320's rated amperage delivery. Lighter is always better in electric park flyers. I believe the video below will testify to the excellent speed and handling of this lighter setup.

I spent a few hours carefully applying the beautiful decals that Ultrafly provides in the kit. Another detail I chose to spend time on was that of touching up the factory paint job, especially on the previously beveled leading edges on all of the control surfaces. I decided to omit the installation of the landing gear on my Warhawk. I have been flying "gear-less" park flyers for years now, and I like the weight savings that leaving the gear off provides. Have I mentioned yet that lighter IS always better when it comes to electric airplanes? Leaving the landing gear off allowed me to come in at an AUW of just over 20 ounces. The specifications show this plane coming in at around 22 or 23 ounces. Saving a few ounces is nothing to sneeze at. However, Ultrafly provides a very complete set of mains and a tail wheel in the kit should you prefer gear and ROG style takeoffs. I personally prefer the clean look and lines of a Warbird as it screams by on the deck at high speed, its landing gear retracted.

Flying

Basics

My pre-maiden nervousness lasted until the P40 was all of 50 feet away from my hand! With only two clicks of down trim, the plane was dialed in perfectly! The P40 exhibited absolutely no bad flight habits. I have not seen any signs of impending tip stalls during slow speed flight or while setting up for a landing.

Taking Off and Landing

A ROG type of takeoff is the preferred way to maiden any new plane as far as I am concerned. Such a takeoff is much better for minimizing the amount of time where you are vulnerable to any maiden mishaps? A hand launched plane seems more likely to succumb to a negative flight event, as the few seconds from the time it leaves your hand to the point where you have sufficient airspeed and altitude to apply any needed trim inputs can be particularly deadly. My apprehensions were completely unwarranted in the case of the Ultrafly P40. I throttled up to around 60-70% throttle and gave it a easy underhand toss, and it was off and climbing with real authority.

The landings are also nonevents. I eased the power back on my downwind leg, bleeding speed as I turned base. When on final, I had the throttle almost completely retarded. When just a few feet off the ground, I completely killed the motor and flared as the ground rose to meet the plane. The P40 settled in nicely, sliding across the grass with nary a scratch on her under belly.

I was a little concerned about the servos and pushrods being exposed on the bottom of the wing when belly landing but so far I have experienced nothing but smooth landings that cause no damage whatsoever. The Lexan cowl is another potential Achilles Heel, as it hangs down a little lower than the rest of the fuselage, and it does not have any structural support behind it. Thus, I try to flare so that the plane contacts the earth with mostly the broad, flat bottom of the wing if possible.

Aerobatics/Special Flight Performance

The F12/10 brushless motor provides plenty of get up and go for this model. Vertical climb outs, while not very accurate or scale for this plane, are as long and high as you prefer. With this much power, very large loops are possible. Rolls are very scale, both in appearance and speed. I may increase the throw on the ailerons in the future, but for now I really enjoy the authentic rate of roll. The rudder has enough throw and area that knife edge flight is possible. It also allows very nice stall turns. I found myself feeling a little concerned that the fiberglass spar in the wing might not be adequate enough reinforcement for the foam wing, as this power setup allows some very high speed yanking and banking. I think my worries are unfounded, as after a half dozen high speed and highly aerobatic flights, the P40 wing looks fine and shows no signs of stress at all. I especially love the high speed passes you can make, down on the deck, with a steep pull out heavenward as a turnaround maneuver

Is This For a Beginner?

Definitely not! This low wing Warbird goes exactly where you point it, and you have to fly it from hand launch all the way to the landing. At full speed, it will get small very quickly. The vertical is unlimited on the F12/10 motor. Beginners would have their hands full with this plane. However, I would definitely describe it as a very stable, easy flying intermediate plane. With the control throws and expos set as recommended in the manual, it is well behaved and solid. It exhibits no bad habits or erroneous and unexpected flight behavior. It does whatever you tell it to do, without talking back!

Flight Video/Photo Gallery

Downloads

Conclusion

I have built and flown more than a few of the Ultrafly planes. The T45 Hawk was my first. I loved it (RIP)! I still have a Sukhoi 27 and an Outrage biplane by Ultrafly that I regularly fly. These kits are great. The P40 Warhawk continues the tradition of providing the buyer a very complete and thorough kit. This is the first Ultrafly kit I have had that was pre-painted, and it looks great right out of the box. If you want to spend the extra time, you can sand and glass these foam kits, spending as much time as you want detailing them and finishing them And you end up with a very nice looking plane. Or you can build them as they come out of the box, apply the gorgeous included decals and still end up with a very nice looking plane. Either way, they fly great! The engineering and research that goes into these kits is more than apparent.

Thank you Charlie from Ultrafly! Keep up the great work, sir! Look for this plane and Ultrafly accessories at your local dealer.

Pluses:

  • Very fast when equipped with the Ultrafly F12/10 motor
  • Comes out of the box pre-painted
  • Builds up very straight and true
  • Very thorough kit; just about everything you need to finish it without a trip to the hobby shop.
  • Two sheets of beautiful decals included.

Minuses:

  • Does not come with a pilot figure.
  • Using a larger battery will require removal of foam in the forward fuselage in order to be able to hit CG correctly
  • Fiberglass wing spar is too short lengthwise to completely fill the groove cut into the bottom of the wing

Last edited by Angela H; Oct 10, 2007 at 12:28 PM..
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Oct 10, 2007, 01:04 PM
The art of Crashing
Good review! One of my most favorite planes in my hanger. I really like Ultrafly planes, wish they made more airframes. I did hear a rumor that they may produce a F4U corsair, hope it's true.
Oct 10, 2007, 01:05 PM
diligentia vis celeritas
gunracer's Avatar
excellent review and video...it really is a well conceived and great flying model...
Oct 10, 2007, 01:17 PM
AA6JB
Bajora's Avatar
And as always, I want to give my "Trigger Man" Blueskyrider a huge thanks for manning my DSLR and videocam while I did the flying.....I couldn't do it without him!

Tnx TR!!
Oct 10, 2007, 01:18 PM
Lover of scale R/C
Matt Halton's Avatar
I can concur everything you have said in this great review Jon,Ultrafly kits are just wonderful.
I have built 2 Hawks,a P-51-D is almost finished,and the P-40 is boxed and ready to get started on.

If anyone has doubts about their flyabilty,dont! If you can't get them to fly well, don't blame the model,you are the weakest link!!

Very slick video,beautifully presented,congrats on a super reviewBring on the F-4U Charlie!!
Oct 10, 2007, 02:08 PM
Dr. Dave
Great review Jon, Really loved the pictures, right on target.
Oct 10, 2007, 02:28 PM
"Have Glue - Will Travel"
dawnron1's Avatar
Excellent job, Jon!
Oct 10, 2007, 04:49 PM
The sky is my playground.
Dora Nine's Avatar
Excellent, love the pics!
Oct 10, 2007, 05:11 PM
I fly, therefore I am.
Cessna 182's Avatar
Nice writing makes a great read! I liked the article almost as much as the plane. May have to get one of one these...
Bil
Oct 10, 2007, 06:09 PM
AA6JB
Bajora's Avatar
You could put that Power 32 on the nose and REALLY take it to the next level Bil! <G>

Tnx for the nice words folks. I really enjoyed doing this review...well, come to think of it, I don't think there has been or will be one that I don't enjoy!?
Oct 10, 2007, 10:39 PM
Registered User
wemattson's Avatar
Thank you for the great review and wonderful video (the music was a real nice touch). I think I just found my next warbird!
Oct 10, 2007, 11:07 PM
Registered User
Mucho applause, fellows. You guys are an outstanding writer/photographer team. Your writing is really getting zippy, Jon, and the video is terrific. I'd love to know what the music is, though. Can you tell me/us? It's a great day when we have the pleasure of your company at Creekside.
Oct 10, 2007, 11:40 PM
AA6JB
Bajora's Avatar
Aw, on behalf of TR and myself, thanks very much Albert.

We're glad you let us in on your little secret known as Creekside. You are all a great bunch of guys and we really enjoy our visits there!
Oct 11, 2007, 12:33 AM
wine country wing nut
BlueSkyRiderX's Avatar
Congratulations JB, this is yet another outstanding review. Thanks for giving me credit for the photo and video documentation. It's an honor and a privilege to work with you on these projects and always looking forward to our next one.
Oct 11, 2007, 06:50 AM
AA6JB
Bajora's Avatar
And Congratulations to you for FINALLY crossing the line, from lurker to poster!

Now, we have a LOT of work to do!!


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