GWS C-47 ARF Review

Review by Nicholas Turner, Staff Contributor

Equipment Used:

- 2x Emax CF2812 1600kv motors

- 2x 22A HURC ESC

- 1x GWS 7035 prop

- 1x GWS 7035R prop

- 3x GWS 9g servos

- AR600 RX

- 3mm collect prop adapters

- Spektrum DX8

Pros:

- Standoff scale  airframe

- Straight forward build

- Parkflyer sized

- Great field presence

Cons:

- Outdated stock power system

- Elevator halves didn’t fit without

significant sanding

- Stock wheels are small

- Stock landing gear angle would cause

nose overs

- Non scale control surfaces

- Not enough stock military decals for

symmetry

- Z bends recommended for both ends

of the pushrods

- Split elevators use a seemingly thin

wire connector

Summary:

 

Mods Made:

- 3S lipo capable battery compartment

- Cockpit held on by magnets to access battery compartment

- Relocation of exit hole on fuselage for elevator push rod

- Brushless outrunners

- 3 bladed props, counter rotating

- Bent LG wire forward to about 110-120 degrees

- Used larger main wheels from GWS P-38 kit

- Dubro mini E-Z connectors

- Moved motor mounts towards wing

 

I received the green GWS Skytrain NPS (no power system) kit from GWS US in the summer of 2014 in appreciation of the work I did with their P-38 kit during the spring. Life kept me busy and I wasn’t able to start the kit until the winter, and even then it was spread out over a three month period as time allowed. Being the green version, I knew I was going to select a color scheme from WWII as my way of honoring those who served.

 

Unboxing

Very similar to the other GWS kit I built, all the foam pieces were individually bagged and laid in the box as to not crush another piece. The instruction booklet and decals were on the bottom, lying flat as to not bend the decals. I quickly sorted through the parts list and checked everything was there for the NPS version. I did dry fit the fuse halves, wing root, and wing panels in place to see what she’d look like. I was happy to see an easily recognizable iconic airframe. Closer inspection of the pieces revealed damage to the leading edge of the vertical stabilizer on one of the fuselage halves. This was easily fixed with light spackle, sanding, and painting after the fuselage was glued together. To my surprise GWS US had also included three 9 gram servos.

 

Building

After much searching on the web I landed on a post on RC Groups where a staff member of Heads Up RC (now Heads Up Hobby), aka HURC, had given their recommendation for power system many years ago. This was followed up by finding a YouTube video showing the plane in flight using the recommended power system from HURC. So I ordered the motors, ESCes, and props around Thanksgiving with the goal of building during December 2014.

 

Prior to building the kit I really wanted to use one of the spare 9 gram servos I had to rig up a door in the fuse for dropping small toy paratroopers. After much investigation, I gave up on this route as the elevator and rudder pushrods crisscross in the fuse, which I feared would interfere with a drop. Due to the roundness of the C-47 fuse, I didn’t want to disrupt the surface with moving the elevator and rudder servos to the tail. I also ended up needing the spare servo in another airframe.

 

The manual was much easier to follow as the pictures were easier to tell what was happening than my experience with their P-38 kit. Prior to gluing the fuse halves together, I cut foam out of the stock battery compartment to allow for a 3S 2200mAh lipo. I also cut the cockpit top off, using an Xacto knife from the inside to ensure I was cutting where I wanted. This did cause pieces of foam to be punched out from the outside. Once I was past the joining of the wing panels to the wing root I started kit bashing, only referring to the manual to ensure all the parts were used correctly. Once the fuselage and wing pieces were glued together, I sanded off the

mold dimples and bumps, and used some light weight spackle to fill the seams and any other holes found. The spackle was sanded down and a coat of latex green paint was applied by hand using a foam brush to the top and latex grey paint on the bottom. I borrowed paint from my friend who had some Behr paint samples made at the local Home Depot to match some of his Parkzone warbirds. Compared to using a traditional brush on the P-38, I found the foam brush gave a smoother, cleaner finish. After getting the base colors on I decided to customize the plane some. At this point I epoxied in three sets of magnets I had purchased from Heads Up RC into the cockpit to hold the battery hatch in place. Using Testors acrylic flat white, I painted markings on the nose and tail to customize the plane. Unfortunately at this point she sat for weeks and I got tired of looking at the plain plane. The green kit comes with decals for invasion stripes for the bottom of the wing, according to the manual, but none for the top. The same is true for the star and bar decal for the wing. Using the invasion stripe decal to create a template I used more Testors acrylic flat white and flat black to paint the invasion stripes on the wing. I then used the stock star and bar decal to make a template and used the Testors acrylic gloss blue and gloss white to paint the star and bar on the top and bottom of the wing. The horizontal stab slides into place through the fuse and is held on by GWS contact glue at the seams where it meets the fuse. I would prefer to have had a larger gluing surface. Due to the tight fit of the horizontal stab into the fuse, shimming the stab to get equal distance from the tips to wing tips as well as levelness can be challenging. Once the stab was in place properly I used a thin tip black permanent marker to mark the joint lines on the stab, just in case it got bumped and moved before I could get the glue on. Test fitting the elevator halves proved the elevators were too long, so I sanded them down from the root, and then discovered they weren’t equal in length. So I sanded the long one down to be equal in length. Now, this created an issue where there was a significant gap between the elevator roots and fuselage. Fortunately I always cut my hinge lines long, so I was able to wiggle the elevator halves around to get the gaps even and still match the tips up with the stab tips. These changes led to the stock elevator control horn location being sanded in half, so I had to move the control horn out some from the stock location.

 

I decided to use the traditional GWS stick mounts for the motor mounts. First test fit with the 7035 props proved with the stock location, I’d be slicing the fuselage. Using the stock mount cutout and the sticks, I lined up the cutout side closest to the fuse with the side of the stick, marked the new width (the sticks I bought were wider than the stock cutout), and used an Xacto blade to cut the foam out to get the clearance needed. Next I test fitted the cowls with the motors, the stock length of the GWS stick mounts had the motors sticking too far out. So I cut the stick mounts down to a minimal length, giving clearance off the foam for the back of the motor, test fitted again, and then epoxied the sticks in place.

 

Feeding the pushrods through the tubes in the fuselage resulted in the new elevator control horn location not working with the stock exit location on the fuselage. Since these are glued into the fuselage prior to gluing the halves together, I had to surgically cut foam out around the end of the tube, then enlarge the exit hole in the fuselage, and glue back into place, as well as shortening the length of the pushrod tube.

 

Servo setup was straight forward. The manual calls for z-bends on the servo control horn and the control horn on the control surface with a V bend in the rod to allow for adjustments. I opted to keep the pushrods straight for strength and use Dubro mini E-Z connectors on the servo control horn with Z-bends at the control surface. Once I felt neutral positions was obtained, I used blue Loctite on the set screws for the E-Z connectors. Setting control throws and neutral positions is just like any other aircraft. Due to reading about tip stalls and ballooning effect on this airframe, I opted to dial in some expo on my rates.

 

My exact setup is as follows:

Surface    Rate/Expo    Rate/Expo    Rate/Expo

Aileron         50%/10%    75%/15%      100%/20%

Elevator       50%/10%    70%/15%       80%/20%

Rudder          50%/0       62,69%/0%   90,100%/0%

 

Throttle cut enabled

As seen above, the rudder movement wasn’t quite even so I had to compensate via the radio programming.

 

After much investigation, I decided to stuff the ESCes in the fuselage. I wanted a nice clean install. Calculating I would only be pulling about 11A max at WOT; I’m not terribly concerned about overheating. The ESCes are stuck to the inside walls with double sided tape. To hide the ESC to motor wire leads, I had to widen the stock channel in the bottom of the wing, as well as pull wires into the fuselage. The RX is stuck to the roof of the fuselage with double sided tape.

 

The stock CG is 50-55mm from the LE of the wing’s root. I read many older threads on the web where these values were consistently too far forward. Given the purpose of the full scale C-47, there is a wide range of CGs being used on the model. I opted for the most commonly reported 60mm. With the stock 3S 22mAh lipos, the C-47 balanced at the stock 50mm location. The kit comes with clay for the purpose of balancing the plane. Since I couldn’t get into the bottom of the fuse without cutting it open, I molded the clay around the tail’s bottom until CG was achieved (just a slightly bit nose down at the 60mm mark).

 

Flight

The day of the maiden flight was picture perfect, cloudless blue skies, no wind, temps in the mid-50s (Fahrenheit), and only about five people at the field. Range check was successful, a friend held the plane, I entered rage test mode on the TX, set throttle to about 50% and walked the proper distance. No issues were observed. Control surfaces were double checked. Due to the lack of ground clearance, the C-47 was carried out and placed in the middle of the runway. Another control surface check was performed; ensuring low rates were enabled on everything. I prefer a nice scale takeoff, and from reading through the web as well as watching older videos if this plane is taken off to quickly she’ll tip stall and crash. As the motors came up to speed the plane veered right. I climbed the plane to altitude and performed coordinated right hand turns. I cruised around the sky at 50% throttle with plenty of power. I found low rates were sluggish and progressed up to high rates, where I felt most comfortable with the control responses. I needed around 14 clicks of up elevator and several clicks aileron trim. Being a Gooney bird, I kept aerobatics out of the equation. I inadvertently stalled her, to which she just nosed over on the wing root’s leading edge. Despite being super nervous and scared of tip stalls, I was comfortable with the C-47 after two minutes of flight and performed several low passes. I had set my timer for six minutes; the DX8 gives me a one minute warning. So at five minutes on the TX, including the time for range check I landed. Knowing warbirds need to be flown in, I flew her in. I kept the speed up and settled her nicely. I checked the lipo and was only at 3.9/4.0V per cell, so I put the lipo back in and went up for another two minute flight. This time the flight was less nerving, but same style of flying as the maiden. This time I landed with a picture perfect landing. I decided to try to taxi the C-47 back; it was doing a decent job as it cut the grass, until one of the blades hit a clump of dirt and broke. Sitting on the flight line through the day resulted in the thin plastic cowls warping, it was only in the 70s (Fahrenheit) that day. This plane is going to have to sit in shade out at the field.

 

Conclusion

I was pleasantly surprised by how well the C-47 flew. If you watch the maiden flight video you hear me say this. There are so many posts through the years on various forums that make this kit out to be one of the worst flying. However, I found this not to be the case because I kept the flying expectations reasonable. A C-47 is not a fast flying plane, is not a quick gun-n-go take off plane, and is not designed for aerobatics. Because I kept my flying style limited. I thoroughly enjoyed flying my C-47. The kit needs modernization for stock lipo and brushless power systems. Is this plane for beginners: absolutely not. This plane is more suited for a fourth or later plane when the pilot has skills for flying warbirds (faster landing speeds, flying a plane through landing not gliding in, and able to correct an aircraft in air not relying on self-correcting tendencies). Is this kit for a first time builder? Only if you have help and guidance from an experienced builder. The build is straight forward, but needs tweaking for a modern day power system. Do I recommend this kit? Only if you want a smaller, stand-off scale DC-3/C-47/C-53 airframe to cruise the skies with. Granted at the time of this review I only have two flights on the plane. I look forward to getting my flights on the plane. Building and powering the plane correctly is key to having a good flying plane. I feel the bad reputation the GWS C-47 has gotten through the years are from the stock GWS power recommendations being weak (as evident on my GWS P-38) and pilots not flying a C-47 within reasonable expectations.