Doug Riley
Platinum Member
- Joined
- Jan 11, 2004
- Messages
- 6,982
A student of mine bought one of Larry Neal's 503 DC Butterfly gyros. I got to play with it a little yesterday.
Fit and finish are very nice. The all-steel pump-handle joystick is very similar to the original Bensen unit (which is a good one).
The Air Command ancestry is obvious in the airframe. The front end of the frame is pure Air Comm. The remainder of the craft uses the bolted U-bracket system seen in Air Command, Sport Copter, Soma and to some extent the Gyrobee. This system cuts labor cost and time, but drives structural engineers nuts.
Larry's Metro-launch prerotator is a sophisticated version of the "long belt" device sometimes seen on VW and Soob engines; a pulley on the front end of the crank drives a long belt that runs up the mast, takes a 90-deg turn aft and powers the rotor through a centrifugal clutch. This thing is extremely powerful. There are quite a number of moving parts, including a 12v air compressor that engages the device, six idler wheels, the clutch and (I think) a Bendix. One must keep a very close eye on all this hardware up on the mast; such stuff is always tempted to take a trip into the prop.
The integrity of the pressed-together Rotax crank is an issue when taking power straight off the crank (i.e. not through the gearbox, with its slip function). I imagine that's why this unit does not give the pilot the job of directly engaging or slipping the clutch. These functions are performed by robots: the air compressor and centrifugal clutch.
Most interesting to me was the flying. The machine flies much like a Dominator, but with less pitching of the nose upon throttle changes. The large HS in the center of the propwash makes for very solid pitch stability, even on a somewhat gusty day.
The vertical tail is "half height," not "tall tail," so there's some tendency to roll with engine torque upon takeoff. With practice, you'll know just where to point the stick to minimize this effect.
I landed conventionally and didn't try out the long-stroke gear. We've all the seen the videos.
Ground handling is childishly simple. There's direct nosewheel steering using the rudder pedals, with slack in the cables that lead to the wheel to allow for slip landings. We didn't have a crosswind that would have allowed me to try this out. Direct-linked steering systems tend to be bugged by a tendency to swerve upon setting the nose down when holding rudder against a crosswind. Slack cables, springs and cams have all been used in the past to minimize the problem.
It's always fun to fly a single-place gyro after driving the tandem limo. You do get spoiled by the higher cruise speed of the big machine.
Fit and finish are very nice. The all-steel pump-handle joystick is very similar to the original Bensen unit (which is a good one).
The Air Command ancestry is obvious in the airframe. The front end of the frame is pure Air Comm. The remainder of the craft uses the bolted U-bracket system seen in Air Command, Sport Copter, Soma and to some extent the Gyrobee. This system cuts labor cost and time, but drives structural engineers nuts.
Larry's Metro-launch prerotator is a sophisticated version of the "long belt" device sometimes seen on VW and Soob engines; a pulley on the front end of the crank drives a long belt that runs up the mast, takes a 90-deg turn aft and powers the rotor through a centrifugal clutch. This thing is extremely powerful. There are quite a number of moving parts, including a 12v air compressor that engages the device, six idler wheels, the clutch and (I think) a Bendix. One must keep a very close eye on all this hardware up on the mast; such stuff is always tempted to take a trip into the prop.
The integrity of the pressed-together Rotax crank is an issue when taking power straight off the crank (i.e. not through the gearbox, with its slip function). I imagine that's why this unit does not give the pilot the job of directly engaging or slipping the clutch. These functions are performed by robots: the air compressor and centrifugal clutch.
Most interesting to me was the flying. The machine flies much like a Dominator, but with less pitching of the nose upon throttle changes. The large HS in the center of the propwash makes for very solid pitch stability, even on a somewhat gusty day.
The vertical tail is "half height," not "tall tail," so there's some tendency to roll with engine torque upon takeoff. With practice, you'll know just where to point the stick to minimize this effect.
I landed conventionally and didn't try out the long-stroke gear. We've all the seen the videos.
Ground handling is childishly simple. There's direct nosewheel steering using the rudder pedals, with slack in the cables that lead to the wheel to allow for slip landings. We didn't have a crosswind that would have allowed me to try this out. Direct-linked steering systems tend to be bugged by a tendency to swerve upon setting the nose down when holding rudder against a crosswind. Slack cables, springs and cams have all been used in the past to minimize the problem.
It's always fun to fly a single-place gyro after driving the tandem limo. You do get spoiled by the higher cruise speed of the big machine.