|E-flite T-34 Mentor 25e ARF|
|Wing Area:||545 sq in|
|Weight:||4 lb 10.8 oz empty5 lb 6.9 oz w/battery|
|Servos:||JR Sport ST47 (x5)|
|Battery:||E-flite 4S 14.8V 3200mAh Lipo|
|Motor:||E-flite Power 32 brushless outrunner|
|ESC:||E-flite 60-Amp Pro Brushless ESC|
|Available From:||Horizon Hobby|
The Beechcraft T-34 Mentor was developed in the post-WWII era as a military trainer aircraft to replace the North American T-6/NJ Texan. The design was actually a descendant of Beechcraft's Model 35 Bonanza. By taking several of the Bonanza's design features and modifying them to suit military training, the T-34 was born. In 1953, the United States Air Force was the first to put the T-34 into service, and designated their version the T-34A. The United States Navy followed two years later, and purchased T-34B models. Interestingly enough, the T-34B had several differences from the T-34A. Increased wing dihedral and moveable rudder pedals were two features that were different. Most interesting, however, was the fact that the T-34B had only differential braking instead of a steerable nosewheel. Both the T-34A and T-34B were powered by Continental piston engines. Later, in the 1970s, Beechcraft developed the T-34C Turbo-Mentor, which was equipped with a turboprop engine. The T-34 has proven itself to be a venerable trainer since the 1950s. Countless Air Force and Navy pilots have earned their wings in the Mentor.
A couple of years ago, E-flite introduced a beginner-friendly trainer model based on the T-34. The E-flite T-34 Mentor 25e ePTS RTF model was a huge success and developed a large following. It incorporated a flap system and NACA droops on the leading of the wing. Both of these features helped to increase the stability and slow-flight capability of the airplane. Everything was included in the ready-to-fly (RTF) package, including a full-featured Spektrum DX6i radio. There was demand for an almost-ready-to-fly (ARF) version, so E-flite has delivered again with the E-flite T-34 Mentor 25e ARF. This version doesn't have the radio or the NACA droops that the RTF model had, but it does allow the modeler to choose his own power system and electronics.
The full-scale T-34 that the E-flite is modeled after happens to be N121BC, which is actually a T-34A that is painted up in the T-34C Navy scheme. N121BC is owned by Mr. Bud Cashen, who served in the United States Marine Corps during the Korean War. Mr. Cashen has owned N121BC for nearly 20 years now and flies it to Oshkosh every year. In fact, Bud flies as the "top cover boss" during the big warbird formation flights at Oshkosh. The following picture was obtained from Airliners.net and used with permission of the photographer, Ron Baak of the Netherlands.
Now that we know a little history behind the full-scale and the model versions of the T-34, let's take a closer look at the latest offering from E-flite.
The E-flite T-34 Mentor 25e ARF is packaged in a large, attractive box that is covered with full-color photographs of the model. The model's specifications are clearly listed, and the power options are also depicted. Inside the box, each airframe part is safely packed in its own plastic bag taped down to prevent movement during shipment. The fuselage, canopy, and cowling were all tucked away in their own compartments in the bottom layer of the box. E-flite provides a full set of hardware, pushrods, and robust landing gear.
The amount of pre-assembly done by E-flite should make most modelers happy. The major airframe parts are built and ready to be assembled. All of the control surfaces pre-hinged and the control horns are already installed. The tail surfaces bolt onto the fuselage, so alignment should be a snap as well. The canopy is held in place by two strong magnets at the rear and two wooden pegs at the front. This attachment method is very secure, yet easy to remove when needed. One interesting feature of the T-34 is the flaps: the builder has the choice of building them as fixed flaps or installing a servo to make them adjustable.
E-flite has two recommended power setups for the T-34 ARF:
For this review, E-flite provided the High-Performance Set-up, which includes the following equipment:
|E-flite Power 32>|
|Motor Weight:>||7.0oz (200g)|
|Overall Diameter:>||42mm (1.7 in)|
|Overall Length:>||50mm (1.90 in)|
|Shaft Diameter:>||5mm (.20 in)|
|Number of Cells:>||3–4S LiPo|
|Max Burst Current:>||60A (15 sec)|
|Max Power:||800 watts|
|E-flite 60-Amp Pro|
|Type:>||Programmable Brushless Speed Controller|
|Number of Cells:>||3-6S LiPo|
|Max Continuous Current:>||60A|
|BEC:>||Switch-mode / 2.5A|
|Max Servos:>||7 analog or 6 digital standard-size|
|Weight:>||2.3 oz (62g)|
|Dimensions:>||33 x 76 x 13mm (1.30 x 3.0 x 0.50 in)|
|E-flite 3200mAh 4S 14.8V 20C LiPo|
|Number of cells:>||4|
|Max Continuous Current:>||20C / 64A|
|Dimensions (WxLxH):>||1.70 x 5.40 x 1.35 in|
If you want to fly the T-34 with controllable flaps, you'll need at least a 5-channel radio system. For this review, I used a Spektrum AR6200 DSM2 6-channel full range receiver with a Spektrum DX7 transmitter. Using the Spektrum radio system provides interference-free operation for worry-free flying. No more glitches! The solid and robust JR Sport ST47 standard servos were used on all the control surfaces. A total of four servos are required to fly with the flaps fixed, but you must add a fifth servo if you want controllable flaps.
|Type:>||2.4GHz DSM2 Receiver|
|Number of channels:>||6|
|Size (WxLxH):>||21.6 x 30.1 x 12.3mm|
|JR Sport ST47|
|Type:>||Analog Standard Servo|
|Operating Speed (4.8V/6.0V):>||0.24 sec/60° / 0.19 sec/60°|
|Weight:>||1.55 oz (44g)|
|Dimensions (WxLxH):>||1.52 x 0.73 x 1.32 in|
Additional items required to complete:
The T-34 kit includes a red plastic spinner, but if you really want to add some bling to your T-34, you should pick up one of the E-flite Aluminum Spinners (EFLSP225). Not only does the aluminum spinner add more scale detail to the model, but it is also sure to double the number of "Hey! Now that's a nice-looking plane!" comments you get at the field.
Also worth noting at this point is the fact that no pilot figures are included in the kit. Read more about this later in the article.
Assembly of the T-34 is very quick and easy. I was able to complete my T-34 in one evening of building. Since all of the major airframe parts are completed, the majority of the work involves installing the electronics. Very little glue is needed for assembly, as most of the parts just bolt together.
The assembly manual is very detailed and well-illustrated, so there should be no major stumbling blocks to the builder. If you'd like to read over the manual, here is a link.
The elevator and rudder servos are mounted in the fuselage in the rear of the wing saddle area. The supplied servo mounting plates must be used to fit standard-sized servos. The existing holes are made for the RTF version of this model, and the servos used in that model were slightly larger. The rudder servo requires the use of a heavy-duty servo arm since it is also connected to the steerable nosewheel.
The Power 32 motor is mounted using the supplied aluminum standoffs and bolts. The ESC is mounted to the inside of the fuselage under the canopy. Hook-and-loop tape and straps secured the battery in its rightful place.
The steerable nosewheel is very easy to install using the supplied hardware. It is really important to get the nosewheel mounted nice and straight. If it is not centered, then you may have a hard time keeping the plane going straight on takeoffs and landings. Be sure to check the alignment later when you do your radio setup.
The T-34 includes a very accurately-detailed fiberglass cowling that is painted to match. After all adjustments have been made to the nosewheel and you're ready to button things up, the cowling easily attaches using the supplied hex-head bolts through the pre-drilled holes in the cowling. There is no complicated alignment procedure to get the cowling mounted correctly. This was a huge time-saver! Be sure to leave a little gap between your spinner and cowling so it doesn't rub.
Installation of the tail feathers is very straight-forward. The horizontal stabilizer slides into its slot, and then the vertical stabilizer is inserted so that the bolts extend down to the bottom of the fuselage. Two locking nuts hold the tail in place. After hooking up the control rods, the plastic tail cone is screwed into place.
When mounting the vertical stabilizer, I ran into a bit of an alignment issue. Everything lined up right, but as the nuts were tightened, the vertical stabilizer rotated aft such that the dorsal fin didn't sit flush with the top of the fuselage. Upon investigating, I discovered a gap at the rear of the slot that allowed the bottom of the stab to rock back as the rear bolt was tightened. I remedied this by using a small piece of a wooden coffee stirrer and a sliver of 1/32 ply to fill the gap. When I mentioned this to E-flite, I was told that this problem has been addressed in later kits.
The first order of business in completing the wing is to install the aileron servos into the pre-cut holes. I used the recommended 6" servo extensions here. The pull strings are there to thread the servo lead through the wing. After centering the servo, the pushrods can be installed.
The builder has two choices with the flaps: fixed or controllable. Out of the box, the left flap is connected to a fixed plate on the left wing root. If the builder chooses to have fixed flaps, the right flap is just connected to the Y-shaped pushrod. Adding a servo and swapping out the pushrods will give the builder working flaps. When hooking up the flap pushrod, it is best to have the radio system powered up and the flap servo connected to the receiver. This will allow you to achieve proper alignment of the flaps. The nylon clevises must be rotated several turns to adjust the length of each leg.
Once the ailerons and flaps are hooked up, the wing halves are joined together on the aluminum joiner tube. A small nylon strap and two screws hold the wing panels together. The main landing gear legs are attached to the bottom of the wing by inserting them into the pre-cut slots and then securing them with the provided nylon straps. The completed wing is installed onto the fuse by inserting the tab on the front of the wing into the slot in the wing saddle. Two nylon wing bolts are used to secure the wing to the fuselage.
E-flite provides the recommended control throws in the manual for the T-34. I followed the recommendations and programmed the settings into my Spektrum DX7 transmitter. I did depart from the recommendations on the rudder and set differing low and high rates. My rudder high rate ended up being a little more like 1" with low rate set to about 1/2". I also programmed in 30% expo for low rates and 40% expo on high rates.
As you will soon read, using these settings provided a very stable and smooth-flying airplane.
|Recommended Control Throws|
|Function||Low rate||High rate|
|Aileron||1/4" (6mm)||1/2" (13mm)|
|Elevator||3/8" (9.5mm)||3/4" (20mm)|
|Rudder||3/4" (20mm)||3/4" (20mm)|
|Flaps||1/4" down (6mm)||1/2" down (12mm)|
Using the recommended equipment for the T-34 means that the CG will be close to the recommended range. E-flite suggests the CG should be 4 3/4" to 4 7/8" back from the leading edge of the wing at the fuselage. Since you are supposed to check a low-wing plane's CG by balancing it inverted, you have to be a little careful. I made my marks for the CG range and I turned it over to balance it on my fingertips. I noticed that the area where my CG marks were was not sheeted, so only the Ultracote covering would be supporting the weight of the model. I didn't like that idea, so I transferred my marks outward a little bit to the first rib in the wing. There I attached a couple of small, clear bumper pads to mark the CG. Now I had a solid support for checking the CG.
In the end, with my battery all the way forward, the CG was perfectly in the recommended CG range.
As soon as I saw how nice the T-34 looked, I knew that for it to look complete, it would need a couple of pilots. My search began by calculating the scale of the model, which turns out to be about 1/7th scale. There isn't a wide selection of appropriate military pilots at that scale, so I decided to go for the civilian look. Hangar 9 has some 1/7th scale pilots (HAN9111 and HAN9113) that looked to be just the right size, so I ordered up a couple for my T-34.
The canopy for the T-34 isn't built to allow easy access to the modeler for installing pilots, so I had to get creative. After some head-scratching, I decided to cut a hole in the cockpit floor just the right shape and size for the pilot to stick up through the floor and be secured somehow from underneath. Sounds like a plan...let's see how it works!
Thinking ahead a little, I wondered what would happen once I stuck the pilot up through the hole and lost my grip on him. The thought of having to fish him out of the cockpit bothered me, so I decided to drill out the little hole in the bottom and glue in a small dowel rod to serve as a handle.
The next step was to determine where the pilots would be positioned so it looked scale. After reviewing some pictures of full-scale T-34s online, I marked where the cut in the cockpit floor should be. I traced the outline of the pilot onto a piece of cardboard to make a template. Using a brand new #11 blade, I carefully cut the floor out. Take your time and make several passes to cut through the balsa. Don't try to cut all the way through on the first pass. After some dry-fitting, I was pleased with the result.
Next, I glued some popsicle sticks to the bottom of the cockpit floor and a couple to the bottom of each pilot. Then the pilot was inserted and glue was used on just the popsicle sticks. This method worked out great and really adds a lot of realism to the plane.
Unfortunately, E-flite doesn't include pilots with the plane, but with just a little effort, you too can install some nice-looking pilots in your T-34.
The first thing you want to check when you get your T-34 ready to fly is how well the nosewheel tracks. If it wants to veer off to one side during takeoff or landing, it could cause you some headaches.
The T-34 is a very stable airplane. It flies really smooth and displays no bad tendencies. The Power 32 motor gives plenty of power to make things as exciting as most folks would want. Flying with the recommended control throws for high/low rates, we were unable to make the T-34 stall on low rates. With the flaps fully-extended and throttle at zero, when full up-elevator was applied, the T-34 would just start descending in a nice, gentle "mush". There was no tendency to tip-stall or anything. However, with high rate elevator in the same scenario, the T-34 would definitely stall and drop the nose as you would expect. It wasn't a drastic stall, and was easily recovered.
Also worth noting is that you don't need a lot of rudder in the turns to keep things coordinated. The T-34 banks and turns very well with ailerons and a touch of up-elevator to pull it through the turn. Rudder can be used to keep the turns coordinated, but don't use too much.
The recommended battery yielded about 8-10 minutes of mixed lazy flying and spirited aerobatics. I used my wattmeter and found with a fresh pack, the power system pulled about 41 amps and 627 watts. With 115 watts per pound, the T-34 has some serious power!
I've only flown the T-34 off of grass runways, so I can't compare it to a paved runway. Takeoffs with full-throttle will happen in about 15-20 feet. Using somewhere between 50-75% throttle will yield a more gentle, scale-like takeoff. Using the flaps seemed to help shorten the takeoff roll some, but not drastically.
Landings with the T-34 couldn't be any easier. Landings can be done with or without the flaps. With no flaps, keep the speed up a little bit and be prepared to make a longer approach. The T-34 doesn't want to slow down very much without the flaps deployed. If you drop the flaps to the full-down position, expect the nose to balloon a little on you. Flying final approach with flaps requires you to add some down-elevator to keep the nose down. Without the down-elevator, the T-34 wanted to settle into a nose-high attitude that looked like it might get too slow. It isn't a drastic push on the stick, but a conscious effort is required. It isn't all that bad. I suppose you could mix in some elevator-to-flap mixing, but I felt it was easy enough to mix it out with my thumbs instead.
The T-34 definitely looks great during landings with flaps...very scale!
With the high-performance power system (Power 32 motor on 4S), the T-34 has plenty of power for any sport aerobatic maneuver. Loops are as big and round as you want them, and the vertical uplines are a sight to see. Aileron rolls are kinda slow on the low rates, but nice and crisp on high rates. Snap rolls are just that...very snappy.
Inverted flight is almost effortless with the T-34. Just a slight bit of down-elevator is all you need to fly inverted. Something about those wheels sticking up in the air on those low inverted passes just looks so cool. The inverted performance was a bit surprising to me given the amount of dihedral the wing has. There was no tendency for the T-34 to want to right itself from inverted, so it didn't seem like you had to work to keep it inverted.
The T-34 is no 3D aerobat, but as you can see in the video, it will do a decent torque roll at the top of a nice upline. In the video, when I was flying that upline, my plan was just to hold it as vertical as I could just to see what would happen. Sure enough, as the airspeed bled off, the T-34 started to torque on its own. I was at full power and it just hung there on the prop as it rotated around the thrust axis. Not having inboard ailerons (that would be in the propwash), I wasn't able to sustain the torque roll, and it fell out. Don't think I wasn't trying to hold it in it!
Knife-edge flight took a little work and a lot of throttle, but the T-34 could be persuaded into some decent knife-edge passes. There is a lot of coupling that has to be flown out since the T-34 wants to pull toward the gear. High rate on the rudder is necessary to even attempt to fly knife-edge.
One aspect of the T-34's flight envelope that surprised me was how it handled in slow flight. The T-34 will slow WAY down when you deploy the flaps. I won't call it a parkflyer, but it sure was capable of some really slow flying. By adding in just enough throttle and up-elevator, I was able to fly around the field making turns and such. It was very stable and never really showed any tendency to tip-stall or anything. If I got too slow, it just started descending, so I would add a touch of power and all was good.
I would not recommend the E-flite T-34 Mentor 25e ARF to a beginner. It would make a good aileron trainer for someone who is looking to move up. However, E-flite does offer this same airplane in a RTF version that includes some more beginner-friendly features like NACA droops. The durability of the landing gear, according to John Redman of E-flite, is beginner-proof!
A WORD OF THANKS
I owe a big thanks to my brother, Gary, for helping me out with the pictures and video for this review. He also lent his superb piloting skills for some of video and pictures.I'd also like to thank Horizon Hobby for providing the ARF kit and components for this review. Thank you all so much!
The E-flite T-34 Mentor 25e ARF is a top-quality model that is sure to bring a smile to any pilot's face. Each time we have the T-34 in the air, my brother Gary and I keep commenting on how smoothly it flies. With power to spare, the T-34 is perfectly at home with tearing up the sky with any sport aerobatic maneuver you can think of. Whether you like pushing the envelope with some down-low inverted passes or flying some big, round loops, the T-34 is sure to please. If you're just stepping up to bigger electric planes, the T-34 is a solid performer that will provide less-experienced pilots a quick shot of confidence as soon as they get it in the air.
Last edited by Angela H; Apr 12, 2010 at 06:13 AM..
Wonderful Review Andy. I love the versatility of being able to use my own "stuff" in this E-flite Mentor. I can't wait to give the sticks a wiggle at SEFF in a couple of weeks.
BTW Jeff, the line to fly the Mentor forms behind me.
This is my favorite plane it looks/taxis/flies very scale has a beautiful cross section when landing and best of all it is very tough I have seem mine and others take beatings and come out with just scratches. Having said that I have heard that they dont sell parts -critical components- of the nose wheel assembly so you might want to be careful with that. If they do now I'll stand corrected.
IT NEEDS RETRACTS.
Why Horizon is making nice scale planes, without optional retracts is beyond me. If this had optional retracts, I would have one on order NOW.
I have several hundred hours in T-34s, including two Oshkosh and two Sun n Fun shows. Including flying in the BIG ONE, the 63 plane formation to open Oshkosh 1999 for the 50 anniversary of the T-34.
You flew T-34s, eh? And at Oshkosh? You may know Bud Cashen then. I'd love to have some stick-time in a T-34!
As the plane is meant to be a trainer for first time fliers, the gear was specifically built with that in mind. Its supposed to be able to handle some pretty rough landings (which I can attest to) according to the E-Flite video/press release.
I'd also like to have retracts and I'm sure I'll eventually install them. There are people out there who are already doing modifications with the plane and eventually a tried and true method for retracts will be available for all...
Nice review. Expect I'll get one of these someday. Over 40 years ago I had a flight in a C.A.P. T-34 that was fantastic!
Isn't E-Flite coming out with servo-less retracts? They have one size out now, and at least one bigger size on the way, if I remember that right. Might be another reason why they introduced this bird without them.
My only criticism: Why aren't the aileron servos hidden under a cover? Why do they stick out, on the underside surface of the wing? Is the wing too thin?
About the aileron servos hanging out... well, I'd guess that also goes back to the fact that this is just an ARF version of the RTF trainer. That plane was built to be a rugged, simple airplane for beginners. Simplicity of mounting the servos goes a long ways toward helping beginners. I'm sure it would be easy enough to mount some smaller servos under some hatches in the wing. The wing is pretty thick, but I doubt standard servos would fit inside the wing. I haven't measured it though, just guessing.
Thanks for the kind comments. I'm glad you guys are liking the review!
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