Paul: Who wrote this? There was no name below it.

"A gyro, in a zero speed landing, lacks adequate rudder authority
because the prop is idling and there is no forward speed to produce
airflow over the rudder. It's is one of the great vulnerabilities of
gyros and the reason for a lot of rotor strikes due to a lack of yaw
control in the last moments of a zero speed landing.
The vectored thrust from a ducted fan might fill that control gap."

I doubt whomever wrote it is a gyrocopter (or the FAA term: gyroplane)
pilot.

A lot of rotor strikes and lack of yaw control are not issues in pusher
gyrocopters.  Zero speed landings are possible with some headwind. Very
low speed touchdowns are common, with 10-20 feet rollouts.

Any rotor strikes of gyros one sees on youtube videos are almost
exclusively a takeoff situation, and a result of a pilot not following
their instructor's training to make sure the rotor blades are up to
flight speed before lifting off the ground.

There is no need to develop some sort of ducted fan for pusher gyros.

Kevin Richey
Portland, Oregon


Boyd Thompson wrote that.

Suppose you are landing in a cross wind. Is that possible?

Paul Lamar


   ....and just one more. Hope I'm still on the mailing list. Looking
   forward to the 3Ds of the imbedded ducted fan. Been thinking about this
   issue since I bought the 18a:

   TAIL SURFACES

   The tail surfaces provide stability and control in the pitch and yaw
   axes. These tail surfaces are similar to an airplane empennage and may
   comprise a fin and rudder, stabilizer and elevator. An aft mounted duct
   enclosing the propeller and rudder has also been used. Many gyroplanes
   do not incorporate a horizontal tail surface. On some gyroplanes,
   especially those with an enclosed cockpit, the yaw stability is marginal
   due to the large fuselage side area located ahead of the centre of gravity.

   The additional vertical tail surface necessary to compensate for this
   instability is difficult to achieve, as the confines of the rotor tilt
   and high landing pitch altitude limits the available area. Some
   gyroplane designs incorporate multiple vertical stabilizers and rudders
   to add additional yaw stability.

     http://www.caa.co.za/Safety%20Links/March%202011%20Edition.pdf


Hi Paul,
Perhaps this is what the experienced pilot who crashed my project
   18a was talking about?:
https://m.youtube.com/watch?v=y5zWLTQXcUI
Thanks.
Boyd Thompson

   It will be awhile before I get around to that.

   Paul Lamar

Thanks, Paul. FYEO. I don't want to belabor the point but the gyro community didn't want to acknowledge the in line thrust/buntover issue until after the death of Igor Bensen. The South Africa data indicates that directional control after landing is the second greatest cause of accidents in gyros:

Accident causes as reported

From the accidents reported to the AIID, it was revealed that the leading cause of accidents is power loss during takeoff, followed by directional control after landing. Engine power loss is mostly associated with the technique used by the pilot. The loss of directional control mostly occurs after landing. It was evident that weather also poses a risk, most particularly crosswinds during takeoff and during landing. It was further observed that 6 gyrocopters rolled over after the accident sequence, and 3 of these rollovers occurred after encounters with crosswinds.

page14image1992
The South Africa data also indicates, perhaps because of the small sample size, a high fatality rate; about 1% per total registered gyros, whereas, in the states, the General Aviation fatality rate is about 1.3%  per 100,000 hours of operation. Gyro pilot head injuries from the blade's rotating path of destruction after a blade strike has been a reoccurring theme.
The gyro's great advantage is that it doesn't stall but to make full use of that capability on landing means operating at speeds that are below the effective range of the tail's control surfaces. In my opinion, thrust vectoring with a ducted fan would add significantly to the safety of the type. The gyro isn't particularly efficient to begin with. A 20% reduction in efficiency for the sake of having full control throughout the gyro's low speed envelope, which is what it's uniquely suited for, should be acceptable.
Very much enjoyed the imbedded ducted fan discussion. It's not often you see that brought up. Thank you.
Sincerely,
Boyd Thompson

Since the air is going from the bottom up tilt the rudder axis 45 degree forward to take
advantage of the up draft because of the rotor. It will work in both modes if large enough.

Paul Lamar


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