VQ Models T-34 Mentor 61.4" Electric
From the Manufacturer:
Wingspan: 61.4" (1560mm)
Length: 46" (1170mm)
Wing Area: 663 sq in (42.77 sq dm)
Weight: 7.05 lb (3.2 Kg) will vary with equipment
Wing Loading: 24.5 oz/sq in (74.82g /sq dm) will vary with equipment
Motor: HP-G-91 or G46 (unclear)
Propeller: 14x6 or 13x6 (unclear)
Servos: 4 standard for EP, 2 mini (?)
Global AFR by Vinh Quang R/C Models VQA095 info link
My experience with the E-Flite T-34 Mentor has been so good that when I saw this slightly larger T-34 by VQ Models, I wanted to give it a try. This larger model can accommodate retracts so that helped convince me to purchase it. I'm not really crazy about the "printed" covering, so I thought that when I purchased it, if I didn't like it, I could recover the plane in a scheme that I did like.
When I opened the box, I was very surprised to see how well the covering was adhered to the plane. Not a wrinkle in sight. Normally, you have to go over the covering with a iron for good measure even if it looks tight, but in this case, it was already tight and very well attached. The covering is a PVC film with an adhesive base. It will shrink with low heat. When heat is first applied the film will sag as it expands. Then it will reach a certain temperature and then begin to tighten up. At this point, stop applying heat and let it cool. As it cools it will tighten more. Use only very low heat.
Since printed coverings can be very difficult to repair, perhaps I'll fly the plane now, and later on, down the road (or runway), I will do a recovering. Something to think about for now. I did discover that acetone will remove the "print", so be careful cleaning up any CA spills.
My overall impression of the ARF is very good. The construction seems good and the part fit so far is very good. As with most ARF's the hardware is only fair. I will be replacing almost all of it with Dubro components, especially the nose gear and block. I really love the huge access compartment. The canopy is very well built and should hold up well. The control rod guides running aft are too long and will have to be trimmed (easy to do) as the elevator and rudder servo's mount in the large "square" aft of the battery holder cutouts. The wings have plastic tips, not so crazy about that, but OK. The plastic wing tips are understandable, as this covering probably would not conform well to the compound curves of the wingtip.
Best yet, ALL the control surfaces are hinged for you, The ailerons and flaps are also glued, you just have to glue in the elevators and rudder.
I did have some parts missing; like the "2nd" pilot as shown in the box photo. No landing light. No Anti-rotation dowels for the wings. Missing set screws for the wheel collars, and 4 plastic hold down straps. No biggy. The only thing that I really wanted was the 2nd pilot.
I was able to determine that standard Hitec servos like the Hitec HS-485HB will fit the plane. Some minor trimming may be needed on the ailerons servos in the wing. The flap servo mounts look like they will fit a HS-85 size micro servo with minor trimming.
Here are some measurements to aid in ordering replacements or for information:
2-1/2" Nose wheel (this is the size of the stock wheel, I would suggest a more scale 2" or 2-1/4" nose wheel).
3" Main wheels (this is the size of the stock wheel, I would suggest a 2-3/4" wheel).
2" Spinner and
4mm landing gear wire (not an issue if you are using retracts, this size plane should really have 5mm wire)
VQ Electric Retracts are available as an option. Hobby People currently are out of stock but sell them for $149. I am not convinced that they are worth the price. If all the legs have good looking struts, then they might be OK for the price, but a photo on the VQ Warbirds website just shows the nose wheel with a strut. I think there may be better options out there. If anyone has more info or experience with the VQ retracts, please let me know.
The manual does not mention the nose gear doors. The way they are made, I don't think that they were meant to be operational. I think that VQ meant for them to be open all the time. This would certainly save time on the build, not having to install and fit doors.
Brushless Outrunner electric motor: Rimfire .55 42-60-480
ESC: Castle Creations Phoenix ICE 75A
Motor Battery: Haiyin 6S 5000mAh 25C Lipo
Receiver Battery: LiFe 2S 6.6v 2100mAh (A123)
Propeller: APC 15x8 Thin Electric Propeller
Servos: Hitec HS-485HB Deluxe HD BB Karbonite (Aileron, Elevator, Rudder). HS-85 BB or MG for flaps. HS-82 for steering.
Futaba R617FS 7-Channel 2.4GHz FASST Receiver
Futaba 7C 2.4GHz Radio System
Weight without batteries: 6.94 lbs = 111 oz = 3.15 kg
Weight with 6S 5000 Lipo and 2S 2100 mAh LiFe batteries: 9 lbs = 144 oz = 4 kg
Wing Loading: 144 oz / 4.6 sqft = 31.3 oz/sqft = 95.4 g/dm2
Wing Cube Loading (WCL) = 14.6
Modifications and Notes:
Electric Retracts: 60 - 120 Tricycle Electric Retracts by E-flite (EFLG430). This tricycle gear set fits well with small amounts of trimming for the "spring" of the mains. I did reinforce the mount by adding hardwood to the "bottom" of the mount before trimming. UPDATE: September 2016; Wow, these retracts are still going strong, I have many hundreds of flights on this plane, and I am so very satisfied with how well these retracts have held up. Sad, to discover that they were discontinued.
Robart Trike Gear Strut Cover's (106) were modified for the mains and nose. I had to drill out the mains to 5mm to accommodate the thickness of the strut wire. I painted them an off-white, with silver oleo's. If I really like the plane I may invest in the more scale Robart Left Hand Offset RoboStrut (651L) for the nose.
I used a Turnigy 3 Channel Servo Speed/Direction Regulator to delay the flap motion to look more scale.
A landing light was added to the cowl. I used a 3W Cree module with a custom made heatsink. Power is from the 2100mAh LiFe battery that also supplies power to the retracts (just an update note: I have been using a 1100 mAh LiFe battery instead of the 2100, it is lighter and lasts all day long).
As usual, and electronic interface board for the LiFe battery was constructed, this time to permit easy injection of LiFe power to the retract/light circuit.
For steering (I like to have steering separate from the rudder so I can use separate trim) I used an HS-82 I had lying around connected to a separate channel. I had to make a mount and place it in the wheel well.
I found to balance the model, I had to build a "cover" to allow mounting of the batteries aft. The electronics sit underneath this cover.
December 18, 2013: Good ground tracking and nice take-off. The plane has plenty of power with this power system. I needed a few clicks right aileron trim and some elevator trim. Once the gear was retracted I flew a few circuits to get a feel for the plane, It fly's a bit "heavier" (as expected) than the Eflite T-34, but I liked how well it tracked in the air. The CG in the manual is about "right on", a little towards the nose-heavy side as it should be for first flights. The control throws in the manual I found should be stated as "low rates", even at those rates, the rudder and elevator have good authority. Landing was very easy and it just slid in both times I flew it. A bit of power just before touch down and it will settle perfectly.
I did a stall test, and it did give notice, and dropped a wing. The rudder is effective. The second time I stall tested it, it mushed straight ahead a bit longer, then dropped a wing, so while not super stable like the Eflite T-34, it does have good stability, so you would have to be really "creative" to have a problem.
Power Figures (Stock System):
Wide Open Throttle (WOT): with 6S Turnigy 5000 mAh 30C Lipo:
With APC 15x8EP: 23.64 V, 56.39 A, 1339.2W (battery 25.10 V initially)
Wide Open Throttle (WOT): with 6S Turnigy 5000 mAh 30C Lipo:
With Xoar 15x8PNJ: 23.80 V, 49.54 A, 1186.4W (battery 24.89 V initially)
New power readings March 2017 for the Rimfire 0.55 motor
Updated the receiver to receive telemetry information with my new Futaba 18SZ transmitter, using a R3006SB receiver.
In doing so, I removed the cowl to redo the lighting system and discovered that the motor wires were a little, let's say, melty. No shorts or anything, but definately time to consider propping down.
Power measured with wattmeter (on 6S lipo, with Castle 75 Edge)
23.83v, 54.16A, 1295.5W
23.80v, 49.54A, 1186.4W
23.97v, 41.37A, 1010.2W
23.3v, 41.76A, 1003.9W
23.93v, 39.67A, 969.1W
I'm going to try the APC 14x8.5 first. It is a reduction of about 300 watts (23%) from about 1300 watts to about 1000 watts. That should lower the temps in the cowl a bit. AUW is 8.8 pounds. Let's see how it fly's at 114 watts per pound (from 147 W/lb.)
ImagesView all Images in thread
Last edited by nioa; Mar 06, 2017 at 10:40 PM. Reason: Added new power figures
The model is going together well. (click on the images to enlarge them).
Servo Mount Reinforcement
I have installed the aileron, elevator, flap, and rudder servos. In each case, I added some reinforcement to the servo mounts. The stock mounts are thin and the attachment screws can easily "strip out". Some additional 1/8" balsa stock added to the inner side, hardened with thin CA, seems to have done the trick.
The elevator servo uses a tray to position the arm so that it is in-line with the movement of the elevator control linkage. If the servo was mounted the usual way, the side-to-side movement of the arm would affect each half of the separate elevators. They would "wiggle up-and-down" as they were operated. This mounting method eliminates that entirely.
Rather than glue the stabilizer in by putting epoxy on the fuselage contact points and then having glue spread out all over the stabilizer half as the stabilizer is inserted into the fuselage, I realized that I could put the stabilizer in place and then apply epoxy.
I made a cooling exit in the tail that allows access to the stab. This is the access point for the epoxy.
An epoxy brush through the access hole lets you apply a good amount of epoxy without making a mess. Later on, I placed a piece of clear tape in the back of the access hole to seal off the aft tail section to keep air from compressing in the back of the tail, reducing drag.
Before the vertical stabilizer is glued in, I would suggest trimming the trim piece that completes the tail end. A piece of balsa glued to the trim acts as a way of firmly securing the trim piece to the fuselage. Make sure you remove the covering directly below it so that the glue has something to hold on to.
The rudder needed some slight trimming to shorten it. It was about a 1/16" of an inch too long to sit flush in the slot.
Once the epoxy has set on the bottom of the horizontal stabilizer, epoxy can be applied to the top of the horizontal stab and the vertical stab at the same time.
This shows the completed assembly:
One thing I was not too enthused about was the rudder control linkage path.
The curve in the wire creates a bit of resistance that really doesn't need to be there. I did use the stock control horns; the elevators lined up perfectly with the holes at the furthest attachment holes, not so with the rudder. The rudder linkage alignment would have been fine if you needed the hole nearest the base of the horn, but if used, the control throw would have been ridiculous.
Fit wise, the attachment of the stabilizers was absolutely "perfect". No complaints whatsoever. Big thumbs up on that!
The electronics bay housing the receiver. The receiver has a guide tube for the antenna that runs aft, this tube keeps the antenna wire straight. You can see the interface board to connect the LiFe battery. The board provides strain relief for the wire and an injection point for retract/light power.
This is the bay with the battery mounting cover in place.
A bigger view.
The canopy "skewer". Instead of using the two little nylon bolts provided, I like to use a single threaded "skewer" so that I just have one fastener. The rod is 2-56 that is soldered to a brass "knob". A guide tube glued to a piece of foam (EPP in my case) is used to allow effortless alignment. A 2-56 blind nut receives the skewer and is glued into the opposite side of the canopy mounting finger. The thread on the end of the brass knob has no mating receiver, I just didn't file it off. Once in place, it only has to be snugged up and not too tight, as it will not move in flight.
The nose gear electric retract installed. A separate steering servo, Hitec HS-82MG was used only because I had it on hand, as almost any metal gear servo of like-size could be used. I had an extra receiver channel and I like to be able to trim the nose wheel separate from the rudder.
Electric retract main. The 60-120 size tricycle set fits well. Just some trimming for the "spring" in the landing gear wire.
The nose gear up close. Robart 106 trike plastic struts that fit "over" the landing gear wire. Not scale, but better than just plain ol' wire.
Main wire gear strut cover. I think Dubro has started to "shine up" those tires. I never gave em a coat of wax.
Here is the wiring diagram for the retract and lighting circuits on a separate LiFe battery. A PDF that you can print is in the "Files" section below.
Last edited by nioa; Dec 06, 2013 at 03:09 PM.
Readying for flight
The day was gusty and cold, but I wanted some shots of the plane for the camera. The gear doors are, in fact, just taped on for the photo shoot. I plan on adding actual operating gear doors later on.
The landing light is on when the retracts are down. A mix on the radio turns off the steering when the retracts are in the up position.
Last edited by nioa; Dec 06, 2013 at 01:58 PM.
Hi, looks great your T-34 and congratulation to successful maiden flite.
I building the same kit and would like know if you use the suggested wooden motor mount for electric motor ? It works good ?
I´m not sure to take a metal motor mount to get more stabilisation.
Greetings from Germany ! Birk
Thanks! It is fast,and has great climb. I'm looking forward to more flights.
The motor is from my Reactor. It is a Rimfire .55 with the matching medium metal motor mount. I used this motor and mount because I had it available, and I thought that a .46 sized motor might be too small.
The wooden mount that came with the kit is fine, but the stability and strength would come from the standoffs (the standoffs are not included in the kit). If you go that route, you can purchase another motor mount to put "in between" the standoffs to get better stability. I think I set my mount up at about 64mm's. If you have a metal motor mount, I would use it. I would also beef up the firewall a bit too.
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