Thanks guys! Flynn, I'll get some photos tonight since I have the mechanics out of the airframe. I've been focusing on the model part for two reasons. First, the mechanics are generally pretty straightforward, and not that interesting. There's not a lot your are going to do that is atypical on that end. However, I guess this one is pretty different in that respect.. Second, is that its a pain to get the mechanics out of the fuselage, so I try to minimize that process as much as possible. Here is the breakdown on the mechanics. It started from a Trex 500ESP kit, but hardly has any of those original parts now. Here are the modifications:
-Special side frames were included from the kit to lower the tail boom
-A smaller diameter 120T main gear was included with the kit to fit inside the narrow fuselage
-This smaller low tooth-count gear increases the gearing ratio, so it requires a lower KV high-torque motor
-This makes things EXTRA difficult running a 4 blades head, which requires a low headspeed (~1700 rpm)
-The instructions specifically call out NOT to use a 12T pinion or less on the motor because it could damage the gear, making it even more difficult to get the correct headspeed (Most Trex 500s runs a 1600kv motor, I run a 900kv)
-The drop down tail is designed to be belt drive. Personally, I am not a fan of belt drive tails on scale helis. There is always a bit of lag/slopiness associated with a belt drive that takes away from making a model look scale in the air. I found a guy on RCgroups who sold a special drop down gear that allowed me to convert to Torque tube.
-Then there was the raised tail gearbox. It started as the RC Aerodyne part:
http://www.scaleflying.com/Torque-Tube-Conversion-Kit-500-size_p_2645.html, but it had a max tilt angle of 45 deg, and the Apache's tail is at about 74 deg. I designed some new side frames for the gearbox and had them laser cut.
-Also changed the pitch bellcrank to the other side of the gearbox to accomodate the right-side Tail rotor. Got that from here:
https://shop.microhelis.de/Crank-Arm-for-500-Size
Specs:
Head: Align 500 size 4 blade
Tail rotor: CNC Helicopter 500 Apache Tail Rotor
Blades: eHirobo CarbonHobby 425mm scale blades
ESC: Castle Creations Talon 90A
Swash Servos: 3x Align DS515m
Tail Servo: MKS DS8910A+
FBL Controller: iKon2 with Bluetooth (I can adjust every setting from my phone without needing to pull the mechanics!)
Motor: Orginally planned as an Xnova 890kv 2820, proved too weak. It was originally designed for a 4 lb heli, and this beefy bird weighs in at about 7.15lbs... I have a Scorpion 3226 900kv motor on the way with a lot more power (1770W vs. 1000W). Hopefully that does the trick.
Batteries: 2 x 3S Roaring Top 3700mah in series. These barely fit under the cockpit with maybe 1mm to spare. Cramming all of this stuff in a small gunship doesn't leave much room.. I have a Huey and an H-34 on the bench that I'm looking forward to with all of their internal space.