The T-28 Trojan was a training plane produced by the North American corporation from the late 1940s through the late 1950s. The original 'A' model, powered by an 800 horsepower Wright 'Cyclone' engine, was used by the Air Force. The Navy needed more power. The 'B' version of the T-28 had an engine of 1425 hp.
It was a hulking great mass of an airplane. You walked up to it on the ramp, and the wing was at shoulder height. The massive radial engine, with its huge cylinders radiating outwards from the crankcase like the spokes of a wheel, was enclosed in a cowling that towered overhead. All of the access panels and hatches were opened and closed with a special fastener called a dzus fitting. T-28 pilots therefore all wore a "dzus key", a sort of screw-driver like tool mounted in a pocketknife grip, with which you could open the dzus fittings by rotating the slotted head 90 degrees. The dzus-key was the badge of distinction for T-28 pilots. That, and an oil-stained flight suit. Because the T-28 was an infamously oily aircraft... the oil-tank, which you checked during your preflight inspection before every flight, had a capacity measured in gallons, not quarts or liters, and if the plane wasn't leaking oil onto the ramp as you walked up, you didn't fly, because that meant it didn't have any oil.
From Ring Wraith's entry on the T28 Trojan at everything2.com.
What is not to like about an airplane described as above? The T28 was noted for the way its cockpit put the pilot up on high instead of nestling him deep within the cockpit instrumentation and controls as was the case in most warbirds. And unlike many of the other vintage planes, there are upwards of 400 restored T28 Trojans flying in the hands of the civilian pilot ranks today.
I have not ever built or flown an electric radio control plane of this size. I was very excited to get the chance to build and fly this large ARF version of the T28 Trojan. It is an excellent way to transition from the smaller park flyers into the larger 60 size warbirds. I someday hope to own and fly a 30-40% size plane, and this T28 is a step in that direction.
|Weight:||7.3 Lbs (7 Lbs. 14 ounces as built)|
|Servos:||Cirrus CS601BB 6kg/cm Standard Servo (6)|
|Transmitter:||Multiplex EVO 9|
|Receiver:||Cirrus RM RX-8 DC Shift Select|
|Battery:||Impulse 11.1V 3200mAh 20C|
|ESC:||Castle Creations Phoenix 80|
|BEC:||Castle Creations BEC|
|Manufacturer:||Black Horse Models|
|Available From:||Hobby People|
|Size:||Replacement for 60-size glow engines|
|Bearings or Bushings:||Ball Bearings (3)|
|Recommended Prop Range:||14x8 to 16x10|
|Voltage:||18.5V to 29V|
|Resistance (Ri):||.065 ohms|
|Idle Current (Io):||1.30A @ 10V|
|Shaft Diameter:||6mm (.24 in)|
|Weight:||396g (13.0 oz)|
|Diameter:||50mm (2 in)|
|Length:||65.5mm (2.57 in)|
|Maximum Burst Current:||64A (60 sec)|
|Cells:||16-24 Ni-MH/Ni-Cd 5-8S Li-Po|
|ESC Timing in degrees||20-30 (High)|
My first thought upon opening this huge box, systematically unpacking and inspecting all of the contents, was that I was amazed at the quality of this model for the price. The Oracover covering is absolutely beautiful, and mine had nary a wrinkle. The fiberglass cowl is pre-painted, and it perfectly matches the covering. Many of the steps normally required to assemble an ARF like this have already been completed for you at the factory. All of the control surfaces come pre-hinged and pre-attached for you, in itself a huge time savings on assembly. The included hardware package is quite comprehensive and complete. Even though I am somewhere near the bottom of the list of the world's fastest builders, I knew this one was not going to take long at all.
The assembly manual is a black and white series of pages. Though not the most polished manual I've used, it is very well illustrated and perfectly adequate to get the job done. There are so few pieces to this ARF, and so much of it is already completed at the factory that it goes together quickly.
The wing comes with strings installed to assist you in pulling the servo leads to the center. It also comes with several aligning dowels installed, both to align the halves to one another when gluing them together and to position the wing in the fuselage wing saddle. The control surfaces are all pre-hinged and pre-attached, which in itself will save a lot of time on the assembly of this ARF.
Mount the servos to the underside of the servo compartment doors.
It is necessary to use 12-18 inch extensions to get the aileron servo leads back into the fuselage. The flap servos can utilize shorter ones. Once the servos are installed and wired back to the center section of the wing, it is time to drill 6mm holes for the four control horns.
They are quite heavy duty when compared to what is normally used on smaller park flyers. After assembling the short and sturdy pushrods for the flaps and ailerons, it is time to glue the two wing halves together.
The heavy gauge wire used for the landing gear should stand up to any less than perfect landings. The nose gear comes with a flat spot already cut into the wire, and it aligns itself nicely when inserted into the nose gear block.
The fuselage almost requires nothing to be done to it to complete it. It comes out of the box with the two pilots sitting in the cockpit, the canopy pre-attached to keep them locked in, ready for the first flight.
There are only a few things that you have to do to assemble the fuselage. Attach the huge fiberglass cowl by drilling four small pilot holes and then anchoring it with four small screws. Mount the nose gear block on the firewall in the same way. There are four little dents to mark where you need to drill the pilot holes on the firewall.
The pushrod sleeves and actual pushrods for the elevator and rudder are also already installed for you, including the assembly to connect the dual pushrods on the split elevator halves. The only detail you must see to is making a small cut in the Oracover to allow the pushrods to exit at the rear of the fuselage. You do have to insert the pushrod for the nose wheel steering but it is a quick job, with a small batch of epoxy used to anchor it at the points where it passes through the former and at the firewall.
As is true of the four control surfaces on the wing, the control surfaces on the tail all come pre-hinged and pre-glued. All that is left to do is first glue the horizontal assembly into its recessed location, and then follow that with the vertical tail assembly. It also has a pre-constructed base that almost snaps onto the fuselage, minimizing alignment worries. You will, of course, have to carefully remove a strip of the Oracover on each as instructed by the assembly manual. And I did double check the squareness and correct orientation of all tail surfaces before epoxying them in place.
Once you have attached the control horns and adjusted the lengths of the pushrods, you are finished with the assembly of the tail feathers.
The internal light ply skeleton of the T28 comes with servo cutouts for the elevator, rudder and throttle servos. This build will only require two of the three mentioned. The full size Cirrus servos slipped into the cutouts without need for any modification. The Cirrus 8 channel receiver was wrapped in protective foam and zip tied to one of the ply cross braces.
For the first time in my electric modeling career, I used a BEC in a build. Castle was kind enough to provide one of their brand new BECs. I was amazed at the tiny size of it. But with 6 full size servos going at the same time, it is not hard to see where you could easily exceed the built-in BEC of a typical speed controller, usually around 3 amps. The Castle BEC is good for up to 10 amps! I zip tied it to a cross member as well. I like to keep my electronics as neat as possible, so I spent a little extra time trying to conceal as much of the wiring and leads as possible.
Because this ARF was originally designed to be nitro powered, there are a few changes that have to be engineered. At the same time, there are a few pieces that come with the T28 that will not be used. The included mounts for a 60 sized engine? Not needed. The fuel tank? Ditto. (I would be happy to bestow these components, at no charge, upon any of my nitro brethren who happen to be reading this review and who may need them.) Now that we have trimmed the fat a little, we need to figure out how to mount the motor, speed controller and the batteries.
There are several after market electric motor mounting kits that are available. After thinking about it for a while, I decided I could get the parts I needed at the local hardware store. I picked up four 3" 8/32 machine head screws, a dozen or so nylon spacers in both 1" and 0.5" lengths, some 8/32 blind nuts and both flat and split washers. The assembly manual provides a firewall template to assist you with motor positioning. It also tells you the dimension from the firewall out to the back side of the prop. Armed with these tools and supplies, it only took me around an hour and a half to get the motor mounted. I used the X-mount that attaches to the back of the motor as the template to mark the four holes in the firewall, ensuring I had it centered up so the motor shaft would be aligned correctly in the center cutout of the cowl. I installed the blind nuts on the inside of the firewall. In order to position the KMS motor so that the back of the prop would be at the correct spacing, I used two 1" spacers on each of the 8/32 screws.
There is a lot of unclaimed real estate on the firewall when an electric motor is used. I was a little concerned that I would have to lengthen the wires on the speed controller given the size of this air frame. I decided to mount the Phoenix 80 immediately above the center cutout in the firewall, using Velcro to attach it. This serves the dual purposes of ensuring it gets plenty of cooling from the prop blast, and it positions it in such a way that the battery and receiver leads can reach back to the radio compartment without having to lengthen them. I love Castle Creations’ products and credit their engineers and designers for giving the builder longer leads on these larger capacities of speed controllers since they are often used in larger planes with longer wiring runs.
The other modification that must be made to the T28 is to create a place for the large 6S1P battery to be mounted. Obviously, the large mass of this battery is going to drastically effect the balance of the model. With this in mind, I first tried sticking the battery into the air frame where there already seemed to be a natural space made just for it. This space was originally meant for the fuel tank.
I was pleasantly surprised to see that with the battery in this location, I was very close to hitting the correct center of gravity. Now that the location was selected, I had to figure out a way to securely mount the battery. A trip to the hobby shop for some 1/8 " ply. a few minutes with my Dremel, a little epoxy, a little Velcro and I ended up with a very secure battery mount that positions the battery in the sweet spot for hitting the center of gravity.
To ensure the battery is secure, I also run a Velcro strap around it and the plywood tray that it is sitting on. It is interesting to note that the kit was designed to cradle the fuel tank in this area of the fuselage. As part of this plywood cradle, there are a pair of plywood "ears" around which you can loop rubber bands. These still function as intended except that they now can be used to secure the battery in yet a third manner!
Now is the time to check and recheck that none of the small details have been overlooked. This is best done in the shop, not out at the field just before you fly your maiden flight. But first, I like to drag the scale out and see what the plane weighs ready to fly.
I always try to connect my Hyperion E-meter to the power system and run it up in the shop to get an idea what kind of current we are pulling out of the batteries and through the ESC. I was pleasantly surprised at the number of watts the power system was generating!
The fiberglass cowl is very nice, and I was so glad I did not have to carve it up to create clearance for a muffler. There is a small pre-marked square on the bottom of the cowl that must be cut out for the nose gear strut to penetrate. I was initially a little upset that to remove the cowl would require removal of this strut, as I could not see how I would be able to reinsert it in place after the cowl was attached. It turns out that once you attach the pushrod wire to the nose gear control horn that rides between the bushing blocks of the nose gear mount, the nose gear control horn will remain in position even after you pull the strut out of the nose gear mount. The nose gear pushrod acts as a retainer and holds it captive, making for very easy cowl removal. And the flat spot cut into the strut ensures that you get the nose wheel facing straight forward so that it tracks very nicely on the take off rolls.
Now is also a very good time to recheck the tightness of all connections, both electrical and mechanical. I also used a drop or to of thread lock on all metal fasteners to insure they would not loosen themselves in flight.
The moment of truth! I decided the larger size of this warbird warranted a trip to a bona fide RC flying site instead of the normal school fields where I usually fly. I am fortunate to live near to a very nice site, the Lagoon Valley Electric Flyers Club, located nearby in Vacaville, CA. This location features a pair of intersecting runways, as well as plenty of grass alongside both of them. The other very attractive part of this site is all of the hospitable, helpful and generally enthusiastic and passionate bunch of pilots that fly there. As I pulled into the site though, I have to confess that it never looked as small as it did with the large T28 in the back of my car. The night previous to this outing, I had already verified all of the control throws as being set at the manual's recommended throws. I also verified the CG (Center of Gravity) as being at 110mm from the leading edge of the wing, at the wing root.
The wheels included with the T28 are large enough that this plane can easily take off in mowed grass if necessary. The landing gear is quite sturdy also. I have not flown a tricycle gear plane in some time, so I was pleasantly surprised at how easy it was to taxi it up and down the runways. After a few higher speed taxi runs to check the nose wheel tracking, which was perfect due to the flat spot filed on the nose strut, it was time to take her up.
Though the T28 has flaps, I decided I would not use them for the first take off. In my head, I was repeating a few important things over and over that I wanted to keep in mind for this first takeoff: Hold her on the ground for a long take off roll to ensure she has plenty of airspeed before rotating ... be prepared to counteract any strong leftward pull due to motor torque ... and so on. I advanced the throttle and without needing to feather in any elevator, the T28 flew itself off of the ground as it neared the end of the runway.
My first flight of the T28 went very well, but when it came time to set up for the first landing, I discovered that the Trojan did not want to settle back to earth. It was retaining energy very well, and it took me about a half dozen passes before I stuck the landing. For subsequent flights, I enlisted the help of a good friend and a very skilled RC pilot, Errol Nevalasca. Not only did Errol's assistance free me up to shoot video and stills, he offered many helpful suggestions to improve the landing characteristics of the T28. I ended up adding a few ounces of ballast to the front of the firewall, as well as shifting the battery forward somewhat. I also dialed back the throws on the elevator. The ensuing flights saw the landings get easier and easier, especially with the addition of some flaps. Even though the initial check of the CG seemed to indicate it was correct per the specifications in the manual, the T28 seems to do better with the weight of the battery shifted forward. The T28 looks especially awesome as it comes down the glide slope with the flaps deployed and a bit of power on. It assumes a slightly nose down attitude on the landing approach, which may be a little different than most of us are used to seeing. It is nothing to be alarmed about and modulating the throttle to control the descent and touch down ensures a good landing.
The Trojan has plenty of power to do basic aerobatics, such as loops and rolls. It has outboard ailerons instead of full trailing edge ailerons. This is because it has inboard flaps. The throws of the aileron servos make for very scale looking rolls. Loops are very easy from level flight. Knife edge flight is not really attainable, due to the the rudder throw being limited by contact with the elevator halves. The 950 watts of power being generated by the KMS motor hauls the 7.5+ pound plane with authority but the vertical is not really unlimited. Very steep and aggressive take offs or climb outs are definitely possible with this electric power system though. I was very happy with the performance of the entire power setup, as overall it makes for very nice scale flight performance.
Assuredly not. The T28 is a large plane, and it handles differently than any of the typically smaller park flyers I am accustomed to flying. It "feels" heavier in flight than the smaller electrics, and you have to be somewhat proactive on the sticks. This does not in any way insinuate that it has any bad habits or is the least bit difficult to fly however. Actually, the T28 is capable of flying quite a bit slower than I would have believed possible, and it has not yet showed any signs of falling off on a wing tip or "biting" me with a nasty stall. It retains energy very well and landings involve a bit of patience as you bleed some speed off. Successfully implementing the flaps may also situationally overwhelm newer pilots. Due to it's size, it is best to fly it at regular club sites that are configured to accommodate larger planes.
From the very moment I first opened the large box and inventoried the pieces of the ARF until I completed the T28 and flew it, I was impressed with the quality and composition of this kit. It comes out of the box with many of the normally time consuming tasks already completed. The Oracover covering is very attractive. Many of the pilots at the Lagoon Valley site could not believe how nice the plane looked and flew. It received many compliments every time I took it out for a flight. It was quite easy to convert it into an electric power system. BH Models and Hobby People deserve recognition for making these quality 60 size warbird ARFS available at such an amazing price. If you have been toying with the idea of trying a larger electric powered plane, I encourage you to take a closer look at their various offerings. They are an extremely good value for the money.
I am looking forward to swapping out the two blade prop for a more accurate and scale three blade prop. I also plan to spend some time utilizing the amazing programmability of my EVO transmitter's custom mixers and also to set up several flight modes to more fully utilize the various functions that flaps can provide.
A big thank you to Errol for the use of his "golden thumbs" and to Terry for his assistance with the videos. If only I had two more arms! I could fly AND take photos and videos all by myself!
Last edited by Angela H; Dec 03, 2007 at 10:20 PM..
Tail heavy? On the first few flights, I would say we thought the same, even though the CG was spot on per the instructions. We made some adjustments to allow shifting the battery forward a bit.
We also started out on the conservative side as far as length of flight. I have my countdown timer set at 5 minutes but we will be carefully extending this in the next few flights.
I ordered a more scale 3 blade Master Airscrew prop which I should have tomorrow.
More photos and info to come on this beauty!
What a great value and great flyer this one is.
Last edited by Bajora; Dec 05, 2007 at 12:23 PM. Reason: corrected typo
Jon, you do good work. I learn a lot from you not only about the models, but how to write quality reviews as well. Great attention to detail. I agree that BH makes some great looking models. The war birds are touchy on landing and I have read some install a gyro on the elevator to take out the control porblem. Hey while you are adding retracts, don't forget the flaps!
What size 3-blade will you be using?
Matt, sorry I failed to notice you were the one who posted that first comment! Great to hear from you again! Hope that precious little baby girl is doing great!!
Yeah, that's my private field!! But I have to share it with the Lagoon Valley RC fliers! <G> They are a great bunch fo guys to hang with and they have built the site into a first class venue. I thank them again for letting me in the gate! <G>
78dave: thanks for the very nice compliment. I learn SO much from others too and I think that is what is so great about my second round in this great hobby...the way we can congregate here on RCG amongst other enthusiasts and learn cool things from one another. Flaps!? The T28 DOES have flaps!! It comes out of the box with them. <G>. I have made some programming changes to my EVO transmitter and I am anxious to get her back up in the air to play with them. I set up a flight mode that mixes the flaps in with the ailerons. I also set up a landing mode with an arbitrary fixed amount of deployment of the flaps, to which I can dial in more while flying and it also feeds a little down elevator. The great thing about the EVO is I can adjust the amount of flaps to down elevator mix in flight, without having to land, adjust and then fly again to see how it affects it. The EVOs are great for that.
I will be flying it more this weekend, weather permitting. Our weather of late has been less than great but the forecast looks pretty good for this weekend. Plus I'll be adding a 3 blade prop.
Watch for more photos here!
Tnx Mr. Morgan!! Now, you get back to that information you are compiling for me and that awesome Skyraider you are building. <G> Maybe you'll fly it today!? I sure wish I could be there to see it and photograph it.For my next vacation, I want to come stay with you for a week and see if you can impart some of your amazing building skills and techniques to this ham fisted wannabe, <G>
Last edited by Bajora; Dec 05, 2007 at 03:34 PM.
BARNESJONR: Jon, I was hoping you might do a conversion to electric build the night we talked about my nitro "BH" T-28 which I really like and it just flies fantastic, almost like the real T-28. If you don't want the "NITRO PARTS" that you didn't use during your conversion build, you could send them to me for spare's. Once again you did a fantastic job.
Tommy: and the P36 review is also coming soon.
Jim: I am getting a Master Airscrew 14x9, as I am currently using an APC E 15x10.
Cecil: glad you stopped by AND that we both have this cool plane to fly! PM me your address and they are yours!
Last edited by Bajora; Dec 06, 2007 at 12:55 AM. Reason: prop correction! Currently using,not a 15x10 but a 14x10
Slick Plane and a great review. I have always liked the Navy color scheme on these birds. looks like an awesome flyer.
I saw on one of the UK web sites BH also makes the T-28 in a 40 size- hopefully Hobby People will get some in that size also. I would really like to have a little smaller one
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