I recently built a TREX 550X, which is actually a 600 sized machine, and put it in a Funkey 600 sized MD-500E. It was a big experiment to see if I could fit a modern helicopter into a fuselage designed for older helicopters.
As you can see from the photos and the video, I think it was a success. I had to make almost the exact same cuts and modifications as Chris Reibert did in his review of the Roban MD-500E. The exception is that I carved a small hole in the fuselage for the elevator servo rather than shimming the servo.
The ship has a lighting kit added for dusk flying. The red and green nav lights are in non-scale locations because I did not want to put them on the skid tips. Also, I did not light the tail. Maybe on the next maintenance, I will consider adding lights to the tail. But, with the simple and rugged mounting system along with the reliability of the TREX 550X, that maintenance may not be for a while yet. Currently I have approximately 5 hours on the machine.
The windows and lights were installed with hot glue. I used an Arrow brand hot glue gun from Lowes with a small precision tip. Windows were taped in place then a small bead of hot glue was run along the inside edge. The nose is practically all window. It was quite a challenge to get the windows all lined up properly.
The landing gear were not epoxied like Chris did on his Roban version. Rather, I used a bit of hot glue to hold them in place. The hot glue is flexible, holds really well, and is more resistant to vibration.
The Funkey version does not have opening doors. I can easily reach in and slide out my big Turnigy HD 5000's with no problem. A longer battery might have issues though.
I did not mount the top of the helicopter frame to the fuselage. There appears to be a significant amount of carbon fiber in the fuselage. And the fuselage is rather thick and stiff. After 5 hours I have had no vibration issues in this fuselage. Just make sure you don't inadvertently put torque on the tail tube when mounting the mechs to the floor. Also, I flew with some rigid foam in the doghouse between the frames and the fiberglass. All that did was dampen out the high frequency noise. I eventually removed it because the machine sounds better without it. My mechs are mounted at five points. There are the four aluminum brackets in the cabin area and the foam donut in the tail. That's it. No vibration issues at all. And I have flown her at max forward speed with no bad tendencies.
On the Trex 550X, I am running a flat 70% throttle curve (+40% for the Taranis...-100 to +100) and about +9 to -3 on the pitch. I find that this allows for very nice scale maneuvers with a head speed that is not too high.
Flight times are generally 7 minutes or so. I use the FRSky FLVSS sensor to report when one cell reaches the 3.7 V level. At that time I enter the pattern to land. Generally this yields 3.8V/cell back on the bench.
As you can see from the photos and the video, I think it was a success. I had to make almost the exact same cuts and modifications as Chris Reibert did in his review of the Roban MD-500E. The exception is that I carved a small hole in the fuselage for the elevator servo rather than shimming the servo.
The ship has a lighting kit added for dusk flying. The red and green nav lights are in non-scale locations because I did not want to put them on the skid tips. Also, I did not light the tail. Maybe on the next maintenance, I will consider adding lights to the tail. But, with the simple and rugged mounting system along with the reliability of the TREX 550X, that maintenance may not be for a while yet. Currently I have approximately 5 hours on the machine.
The windows and lights were installed with hot glue. I used an Arrow brand hot glue gun from Lowes with a small precision tip. Windows were taped in place then a small bead of hot glue was run along the inside edge. The nose is practically all window. It was quite a challenge to get the windows all lined up properly.
The landing gear were not epoxied like Chris did on his Roban version. Rather, I used a bit of hot glue to hold them in place. The hot glue is flexible, holds really well, and is more resistant to vibration.
The Funkey version does not have opening doors. I can easily reach in and slide out my big Turnigy HD 5000's with no problem. A longer battery might have issues though.
I did not mount the top of the helicopter frame to the fuselage. There appears to be a significant amount of carbon fiber in the fuselage. And the fuselage is rather thick and stiff. After 5 hours I have had no vibration issues in this fuselage. Just make sure you don't inadvertently put torque on the tail tube when mounting the mechs to the floor. Also, I flew with some rigid foam in the doghouse between the frames and the fiberglass. All that did was dampen out the high frequency noise. I eventually removed it because the machine sounds better without it. My mechs are mounted at five points. There are the four aluminum brackets in the cabin area and the foam donut in the tail. That's it. No vibration issues at all. And I have flown her at max forward speed with no bad tendencies.
On the Trex 550X, I am running a flat 70% throttle curve (+40% for the Taranis...-100 to +100) and about +9 to -3 on the pitch. I find that this allows for very nice scale maneuvers with a head speed that is not too high.
Flight times are generally 7 minutes or so. I use the FRSky FLVSS sensor to report when one cell reaches the 3.7 V level. At that time I enter the pattern to land. Generally this yields 3.8V/cell back on the bench.
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