Date: 201210
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: Amateur/Home Built/Experimental
Operator: Personal
Operating under: Part 91
Flight plan: None
Mission: Training
Flight phase: Landing
ATC / advisory: CTAF ZZZ
Aircraft component: Aileron Control System
Component problem: Malfunctioning
Reporter organization: Personal
Reporter function: Instructor; Pilot Flying
Reporter qualification: Flight Crew Commercial; Flight Crew Flight Instructor; Flight Crew Instrument
Human factors: Human-Machine Interface
Anomaly: Aircraft Equipment Problem Critical; Ground Event / Encounter Ground Strike - Aircraft
Detector: Person Flight Crew
When detected: Other Landing
Result: Aircraft Aircraft Damaged; Flight Crew Landed As Precaution; Flight Crew Returned To Departure Airport; General Maintenance Action
Contributing factors: Aircraft; Human Factors
Primary problem: Ambiguous

Narrative: This was the first flight in this aircraft for both me and the student. I was acting as instructor and had previously done training with this student to get his tailwheel endorsement. Preflight inspection was normal and full control deflections were made to all control surfaces; no problems noted.Takeoff was normal and airspeed was live; climb at 100 MPH. Ten minutes into the flight we experienced what we thought was the autopilot coming on. The ailerons became very stiff and hard to move. We turned off the autopilot and wing leveler; also tried pulling the breaker on the autopilot. All those things had no effect. I also noticed that the aircraft was only indicating about 130 MPH at 23 inches of MAP and 2500 RPM which seemed low for this type of aircraft. We were also having trouble communicating due to intercom problems.We decided to return to the airport immediately rather than do the flight maneuvers we had intended. It appeared that something was mechanically binding in the aileron control system.Final was made at 90 MPH indicated and short final at 80 MPH. The airplane inadvertently stalled several feet off the runway and hit hard on the left gear causing damage.Notes: I had flown once before in this model aircraft and found it to handle very similar to [the aircraft I own]; also the speeds around the pattern were very similar. I have over 500 hours of tailwheel and do tailwheel training in a Citabria 7GCBC. The Mustang II is an experimental aircraft; 180 HP and CS prop. I knew beforehand that the stall characteristics of this airplane were unforgiving; sharp leading edge. I believe that if we had been able to do stalls and slow flight at altitude as planned that this incident would not have occurred.

Callback: The reporter states that the cause of the aileron binding remains undetermined at this time but the stiff feel exists with the aircraft on the ground. The aircraft flight control system is all push rods and bell cranks.



Synopsis: Experimental aircraft instructor with student on first flight for both experiences aileron binding shortly after takeoff and elects to return for a precautionary landing. During the landing flare the aircraft is stalled just above the runway causing damage to the left main gear.