Unique Models T-50 Korean Trainer EDF Jet….. 8-31-11

T-50 slide

See A full Written Review and flying video of the Unique Models T-50 EDF Jet!

The Flight Video with a repair of a foam wing tip missile.

 

Review Status: In progress, not complete, more to come.

Unique Models T-50 from Hobby King

Last updated: 9-3-11.

Left click on any picture to have it appear in a new window. Click on that picture to get more detail.

 

 

 

C.G. : 72-78 mm aft of leading edge where wing meets the fuselage. Mine balanced and flew well there

Control Throws: Elevator 3/4”up & 3/4” Down, Ailerons 3/8” up & 3/8” down

Rates & Expo: Elevator- Rate 70%/Expo 20%, Aileron Rate 60%/20% Expo

Empty Weight: (no battery):  934 grams, 32.9 oz,  2.05 lbs

Flying weight: (with Turnigy 2650 4s 40 c battery) 1261 grams, 44.5 oz, 2.78lbs

Speed: 85 mph

OVERVIEW:

Welcome to the RCInformer review of the Unique Models T-50. I purchased this one from Hobby King after seeing several online videos of the plane. Most of the videos showed a plane that flew ok and had a really “unique” landing gear system/and electrically opening canopy. I expected it to be a good flyer from what I had seen but what I got was much more than expected.

What I found was big value in a small package! This small but very stable flying “pocket rocket” has all the features you would normally find in a larger model for a mere $150 plus shipping. In addition, it will fit in nearly any car quickly and in one piece.

plane car Pic

When I flew it the first time I was shocked at how well it flew for such a small plane. I fully expected any amount of wind to disturb it in flight. Instead what I found is a plane that is super stable and has a phenomenal roll rate. It initially appeared a bit sluggish on takeoff, but once the gear came up and the plane accelerated I was surprised at how fast it raced past me… very impressive for a small plane!

FIRST IMPRESSIONS:

As I opened the box I immediately noticed how well the plane was made. Although the plane is made of EPS foam, the parts were made from very precision moldings and the quality of the assembly was one of the best I have seen… In addition, most of the work was already done, including the electric gear and canopy. Hats off to unique models and their high level of Quality Control… they no doubt have skilled workers assembling their planes… they are saving me a lot of typing.

It became obvious from the get go that this would be a relatively fun and easy build. Unfortunately, nothing is perfect… and there are a few things I have found that are noteworthy… they are small items but definitely things that should be done before flying this remarkable Aircraft.

(1) I noticed that the pushrods for the elevators were long, thin and would be subject to flexing in flight… one online video I saw showed the plane crashing as a result of the flexing. A simple carbon tube installed over the rod makes it rigid and fixes the problem.

(2) After a few flights both elevator hinges on one side of the plane began to pull out inflight which needed re-gluing and taping.

(3) At times the landing gear was intermittent in operation… Occasionally one or more of the struts would not retract.

(4) I noticed that the battery compartment was small.

GENERAL ASSEMBLY:

Building this plane was fun and simple. I just followed the instructions and it all went together easily.  However, as usual, instead of using the supplied contact adhesive, I used EPOXY on all Structural surfaces and lightly sanded all contact surfaces prior to gluing. All that needed to be done for assembly was to glue the wings, elevators, rudder and nose cone to the fuselage. The wings have small fiberglass rods that are glued into each wing before gluing them to the fuselage. IMPORTANT: These parts are a very precision fit. While many other models have some gaps that the epoxy will help fill in, this plane has nearly NO extra space… I used a small 3/8” paint brush to apply the epoxy to get a thin, even application. If too much epoxy is used it will all ooze out making a mess of the model…. Cleaning up epoxy with alcohol can often ruin the finish on a foam paint job.

NOTE: This plane has another “unique” feature that makes it stand out from the others… the manufacturer intentionally did not paint the gluing contact surfaces… this allows foam to be glued to foam and not paint glued to paint. Painted surfaces that are glued together are more likely to fail because you are often actually gluing a wing or tail to a coat of paint and not the actual foam fuselage…. Someone at Unique Models is really paying attention to detail and improving the quality and safety of this model!

HOW I CORRECTED THE ABOVE ITEMS AND MADE IT ALL WORK:

There were 4 previously discussed issues I wanted to address before flying the plane. Mostly items (1) and (2) above were Important to address before flying and both were easy to fix. Below I will detail any corrections or additions to the model.

Please keep in mind that not all kits are the same… the issues my plane had may not be the same as the ones yours has.

(1)  Thin flexible elevator rods:

This is an easy upgrade. The elevator pushrods are too thin and not rigid enough for the length that they are. While in flight and under a load, they can flex causing a loss of control. I simply unscrewed the plastic clevis from the rod and added a piece of carbon tube over the existing elevator pushrods.  I usually keep a few of these rods in my stock as many of my planes have needed this upgrade. Note: The aileron rods are short enough that they do not flex and do not require this fix.

(2) Elevator hinges pulling out of foam:

Many foam planes seem to have this problem. So far I have not had a foam plane that this did not happen to. After a few flights the right half of my elevator hinge began to pull out of the foam. Fortunately this did not come off in flight and cause a crash. Tape greately enhances the security of the flight control surfaces… I discuss this later in this report.

I like to use a bit of oil or “lip balm” on the hinge to help keep the glue out of the hinge while it is drying. In this case I decided to use 30 min epoxy in a medical syringe to apply the glue because I felt it would better fill the voids in this application. In addition, after the glue was dry I ran a 1” thick piece of Blenderm (hinge tape) to help keep the hinge in place and seal the gap.

(3) Intermittent landing gear
operation:

In a few instances my landing gear failed to operate properly. One or more of the gear legs would sometimes fail to extent or retract. I have had this happen on more than one T-50 out of the box… so it may be a common area of concern for this model. For this reason, I speculate that many have had this problem. I noticed that after I wiggled the landing gear control board the gear would work correctly again. One at a time, I would remove one of the plugs from the board while the gear was in transit… I could isolate the struts that were not functioning properly. My conclusion was that the contacts inside the connectors were not very tight and needed to be adjusted. The pin that comes off the circuit board does not fit tightly enough into female end of the plug. The female end must be removed from the plastic connector and compressed more so the male/pin will have a tight contact.

 

To do this, I simply inserted a hobby knife blade or pin in to the plastic locking device that holds the female plug in place and carefully pried it open to remove the female plug.

After removing the metal female plug it can now be adjusted. With a small precision screwdriver or similar tool, I put a bend in the metal contact. The contact must be “pressed in” so the hole in the male end is now smaller. The pin on the circuit board will now fit tightly in the new smaller contact hole.  I used this technique on all the connectors that connect to the landing gear control board. My gear system has functioned flawlessly since applying this correction.

(4) Small battery compartment:

“Stay inside the Box”. At first I thought this battery compartment was going to be a problem. The space is very small and there is not a lot of trimming of foam that can be done without making the fuselage to weak. The sides of the fuselage are thin enough and I did not feel comfortable trimming any from there. In addition, any battery that has to be squeezed into the compartment will spread the sides of the fuselage apart and now the canopy will not close! The good news is that the recommended 4s 2200mah 20c pack is adequate to fly the plane on.

I have used a wide range of batteries on this plane all the way up to a Zippy 4s 3000mah 40c pack. The best balance of size, weight and flight time I have found comes from using a Turnigy 4s 2650mah 40c pack…. little modification was needed for this battery. This battery is wider, thinner and longer than the stock battery. It also has a 106 amp draw limit (2.65x40C) which is much easier on the battery life… the stock pack has an amp draw limit of only 44amps (2.2x20c)… as you can see, the stock pack is operating at its limit and will puff up and wear out faster. Also, if the stock battery puffs….and they usually all do, eventually the canopy will no longer close whereas the 2650 has some vertical margin for thermal expansion.

The picture above shows the modified interior fuselage sides that allow this battery to fit well…. In addition to minimal cutting of foam, this modification also allows the Turnigy 2650 pack to fit under the foam lip which greatly assists in keeping the battery inside the plane during inverted or negative “G” flight. This is how I got away with using a wider battery without modifying the fuselage sides.

Because this battery is heavier than the “stock” battery… I did not push it all the way forward to maintain the same C.G.   When using this bigger battery, I insert a small piece of foam in front of the battery to maintain the same C.G. that it has with the stock battery.

In addition to some foam modification, I had to slightly modify the battery pack insulation for the battery to fit better….. The width of the Turnigy 2650 battery was perfect, but the wires exiting the side of the pack screwed up my calculations… yet another variable to consider…. I simply cut then bent some of the “white” insulation that was causing the wires to stick out of the side and then I used a heat gun to re-shrink the “blue” battery wrap to help hold back the wires.

Lastly, I needed to trim off some of the tabs protruding under the canopy to accommodate the longer, flatter 2650 pack.

Miscellaneous items:

Leading Edge Root Extensions (LERXs):

This plane incorporates Leading edge root extensions or LERXs as do many modern fighter aircraft. The LERX’s are the small thin wing extensions ahead of the leading edge root that joins the wings to the fuselage. The extension energizes the airflow over the wings and allows the plane to fly at higher angels of attack essentially lowering the stall speed. Because this plane is made of EPS foam the extensions are brittle and damage easily. I applied a coating of CA to my extensions to harden them up so they do not damage so easily. I am looking for a better solution for this, please feel free to contact me if you have a good idea and i will post it here.

Hinge Tape:

As with many of my foam planes…I run a 1” piece of “3M Blenderm” (hinge tape) down all five flight control surfaces to seal the gaps. With a high speed model, this helps to prevent flutter. It has turned out to be a safety device for me on many of my models. I began using this tape on most of my models after I almost lost my BH F-18 due to a hinge pulling out of the foam. Even with the tape in place a good post flight inspection will often reveal a hinge pulling out… the tape is good redundancy for the hinge. NOTE: The above picture also shows a piece of black trim tape I used to cover up the spar to make the bottom of the plane a bit cleaner.

Control horn clevises:

More cheap insurance! Thanks to all the cool electric planes out there, many that are new to the hobby missed out on the knowledge that glow powered models provided. I always add a small piece of fuel tubing around all clevises to prevent them from coming off in flight.

Flying:

FUN… FUN… FUN!  It is that simple! This plane has excellent stability in all 3 axis. It groves well and has no bad habits…Another big advantage is that this plane will fly off well maintained grass. Unfortunately, many grass fields are simply too harsh for small jet wheels.

Takeoffs:

Takeoffs with the T-50 are very scale. Many at my flying site have commented on this. With the correct C.G., the nose will smoothly rotate into the air giving a very scale appearance. When flying off grass the takeoff is a bit longer due to the friction of the grass. A significant amount of elevator pressure is needed to rotate the nose into the air. A shallow climb out should be maintained until the gear is retracted and the plane can accelerate to a safer flying speed. The gear in the down position creates a significant nose down pitching moment…I have found that I need to hold some back pressure on the elevator stick after takeoff until the gear fully retracts…. so do not trim the elevator until the gear is fully retracted. In addition, do not be in a hurry to pitch the nose up after takeoff with the gear down or the plane could get slow quickly and a departure stall could
occur. This plane does not have a lot or reserve thrust to climb with when the landing gear is still down! However once airborne and the gear is retracted, the acceleration is very noticeable. Keep in mind that a full 15 seconds is required before the landing gear fully retracts.

Maneuvering:

With the plane cleaned up, little trim was needed and most of the back elevator pressure was no longer needed. Top speed reaches a respectable 85mph. The T-50 is smooth in all flight phases. The roll rate is phenomenal especially with a high rate selected so be cautious when setting aileron throws during setup… only 3/8“ throw is needed to produce a high roll rate…. more throw is still controllable but the plane will roll so fast it becomes a blur. The elevator throw is significantly more than the ailerons and needs the greater travel. Inverted flight is also super stable needing only a small amount of negative elevator.

Approach and Landing:

This plane is a pleasure to land. As the gear extends for landing, the nose will drop and assist in making the airplane descend… again, this is due to the high drag produced by the gear. Even when it is slowed down it handles well with only a slight tendency to drop a wing…. Just stay on top of it, make any roll corrections needed with ailerons and the plane will respond well to your inputs without any negative tendencies. Pitch control in the flare is very predictable and smooth landings are easily achieved.

The most important thing to note is the need to carry some power when the landing gear is down. With the landing gear down this plane requires that you carry more power than seems normal for a plane of this size and weight…. This is due to this airplanes small size combined with the drag produced by the complexity of the landing gear/doors system…. The landing gear on this plane creates a lot of drag that needs to be offset by some additional thrust. With the landing gear down and the power at idle, this plane drops like a rock and slows down quickly. Lastly, as with the takeoff, the gear takes 15 seconds to fully extend…. So plan ahead and get the gear down early enough so it is locked at touchdown.

Features that make this plane stand out:

Landing Gear & Doors:

 

 

This plane has a very effective  landing gear system. It is not just “really cool to look at” It actually does the exact job that retractable landing gear was intended to….it cleans up the drag and allows the plane to fly fast and get the most use out of the thrust the engine can provide. We all look at this system and are pleased with how neat it is, but like many real airplanes, this plane needs this system to fly as well as it does. This is one of the best lightweight and efficient systems I have seen. The doors alone are a standout feature because they seal all holes that would normally be creating thrust robbing drag.

Electric Canopy and External Power Receptacle:

The T-50 comes fully equipped with an electrically operating canopy that worked perfectly out of the box. It came completely installed and ready to go. The opening of the canopy provides access to the battery compartment. I fully expected this electric canopy to be a hassle to use… I was wrong…instead it has performed flawlessly. Unique models has used one of the landing gear mechanisms and converted it to operate thecanopy.

The system incorporates an external power jack (Deans Connector) under the fuselage so that the canopy can be opened and closed without a battery installed in the plane. Please note that this is a well used airplane that has a lot of flights on it and a few repairs.

Receiver Compartment

Located just behind the external power adapter is the receiver compartment. It is opened with a single screw and was wisely ventilated by Unique Models. From this hatch, the receiver and landing gear control board can be accessed. What a great design! It is the small stuff like this that drastically enhances the model and makes servicing it easy.

Nose wheel and rudder

One of the best features on this plane is the nose steering and rudder control. It was very well thought out. Smartly designed… this system incorporates a single servo mounted in the nose gear compartment that drives both the nose gear steering and the rudder …. That’s excellent efficiency! The metal wire attached to the outer servo arm hole controls the rudder from the same servo.  Some monofilament “fishing line” was used for the steering cables… it is strong, simple and adds some cushion to the servo to keep it from stripping… awesome idea… I will no doubt use this idea on many of my other models. The rudder can be easily adjusted with a single screw that is attached to the rudder control horn. NOTE: On my plane I used Gorilla Glue to re-glue the nose gear in place due to a bad landing I had. Gorilla Glue bonds great to foam and fills voids nicely.

Pros:

Skillfully and precisely assembled at the factory.

Parts fit very precisely during building.

Great flying airplane, great stability and fast roll rate.

Speedy for a little plane.

Very cool and efficient electric landing gear and canopy system.

Fits easily in nearly any small car.

At $150 it is probably the best value in an EDF to date.

Cons:

Elevator rods should have carbon tubes around them from the factory.

Landing gear is slow to retract and extend… 15 seconds to fully cycle.

No suspension in main gear.

Wheels are small…. well groomed grass or pavement is required.

All Landing gears are glued in… servicing them is difficult.

Small battery compartment.

Leading edge extensions are thin foam and damage easily.

Plane cannot be disassembled.

Plastic tail cone is sensitive to heat and can melt in sunlight.

Conclusion:

This plane has quickly become one of my favorite models. It is no doubt a great design and was assembled by skilled people. Rather than being slapped together or rushed to production, it appears that this model had a well thought out planning phase. The result is a plane that does everything well. It is easy to build, easy to fly, and easy on the wallet. For around $150 I think it is the best EDF value on the market right now. In my opinion, in the past it was nice to have a large, impressive, and
expensive airplane, however I have found that it is no longer a desirable thing. Now-a-days I generally prefer not to assume the risk of a model that costs in the thousands of dollars. There is less fear and more fun in flying a plane that is not a huge investment. In the past you needed to have a larger, more expensive plane if you wanted nice features like retractable landing gear…those days are gone!  Miniature airplanes like this one have broken the size, complexity and cost barriers of the past.
Instead of thousands of dollars for a jet model you can have it all for under $200 with little fear of crashing the model because it is cheap enough to just buy another one.

TIP: Here is an idea I like with regards to this airplane… instead of owning one expensive model… you could have 2 or 3 T-50’s for less money or just keep a spare airframe in stock to replace your model if a crash should occur (this is what I do!) it is a very cost effective way to go…in addition you now have spares that you can swap from one plane to the other or use the crashed plane for spares. NOTE: The airframe only version from HobbyKing includes, the fan, retractable landing gear/canopy installed, and the nose gear servo installed all for $89! That is a deal!

Notes to manufacturer:

Excellent model! The only change I would add at the factory would be to include 2 carbon tubes over the elevator pushrods as I indicated above. This would greatly improve the safety and reliability of this plane without the builder having to buy anything else. In addition it would be nice in future models to make the landing gear removable with screws instead of being glued in… glued in gear makes them hard to fix or replace. I can’t wait to see what Unique Models puts out next. Even though I like the size of this small model, it would be nice to see a 90mm version of the plane on a 6s system.

Anyway, I am looking forward to Unique Models next jet offering. I will be watching this manufacturer with great
interest. If the T-50 is a sign of things to come… I will have more Unique Models in my hangar…. keep the quality coming!

 

 

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4 comments


  • John K

    WOW! I must say that this is probably one of the best website reviews I’ve ever seen. Very in depth and informative. Lot’s of info, pictures, and videos to keep you sucked in. I too love this jet and would love to get another one. Just waiting for someone to get wise and offer it again. I am surprised that not as many people caught on to this jet as they should have. For how much you pay for, this jet has great quality. I, too, have put out quite a few videos on this jet. “janthony15” is my youtube channels name. I really, really like your website! I have been planning on doing something similar. And though I’ve only seen this page of your reviews, the dedication you have to creating a page like this is commendable. Great Job!!

    John

    September 12, 2012
    • Rich Baker

      Thanks, check out edfhobbies.com, abong-rc.com , applehobby.com, if all else fails try easytigermodels.com…

      Rich

      November 12, 2012
  • May I simply just say what a comfort to find someone that actually understands what they are discussing over the internet.
    You actually understand how to bring an issue to light and make it important.
    More people have to check this out and understand this side of your story.

    It’s surprising you’re not more popular because you definitely
    have the gift.

    October 27, 2012
    • Rich Baker

      Thanks for the kind Words… Interest in my videos is becoming more popular… I am trying to produce useable information to help folks out… feel free to post any of the videos in appropriate places… thanks again! Rich

      November 12, 2012

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