Mooney 20 pilots reported a minor inflight collision while formation flying.

Attributes
ACN	1667885
Time
Date	201907
Local Time Of Day	0601-1200
Environment
Light	Daylight
Aircraft 1
Make Model Name	M-20 Series Undifferentiated or Other Model
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Route In Use	Direct
Flight Plan	VFR
Aircraft 2
Make Model Name	M-20 Series Undifferentiated or Other Model
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Route In Use	Direct
Flight Plan	VFR
Person 1
Function	Pilot Flying Single Pilot
Qualification	Flight Crew Multiengine Flight Crew Instrument Flight Crew Flight Instructor Flight Crew Commercial
Experience	Flight Crew Last 90 Days 45 Flight Crew Total 4600 Flight Crew Type 1800
Person 2
Function	Single Pilot
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Flight Instructor Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 190 Flight Crew Total 3500 Flight Crew Type 1500
Events
Anomaly	Aircraft Equipment Problem Less Severe Conflict NMAC Inflight Event / Encounter Object
Miss Distance	Horizontal 0 Vertical 0

Narrative:

In VFR weather I departed ZZZ in aircraft X; [a] mooney; as second aircraft in whiskey element of two aircraft. Lead aircraft was aircraft Y ('west lead'). We had briefed joining on the two-ship element ahead as '3' and '4' in 'finger-four' formation. As briefed; after takeoff I crossed-under from left to right of lead aircraft to join in normal fingertip on whiskey lead's right. Whiskey lead began closing on the victor element ahead. While maintaining position; I experienced significant wake vortices from preceding 60-odd aircraft. I was moved above whiskey lead and briefly lost sight. I deconflicted turning away and descending from the element. I heard 'tail' (the last aircraft in our formation traveling behind whiskey element) ask whiskey lead if he had 'kissed me off' (released me from the formation) and I heard whiskey lead respond 'no.' I visually reacquired whiskey lead to my left. 'Tail' asked would I rejoin and I replied 'yes.' I rejoined whiskey lead and proceeded uneventfully to ZZZ1 for landing as briefed. At no time did l either observe or experience any flight control issues during the flight; landing or taxi. I was unaware the aircraft had touched until after landing; when I exited the aircraft and observed damage to my rudder trim tab; which I pointed out to whiskey lead pilot. We called the NTSB and made a verbal report.

Original NASA ASRS Text

Title: Mooney 20 pilots reported a minor inflight collision while formation flying.

Narrative: In VFR weather I departed ZZZ in Aircraft X; [a] Mooney; as second aircraft in Whiskey element of two aircraft. Lead Aircraft was Aircraft Y ('W Lead'). We had briefed joining on the two-ship element ahead as '3' and '4' in 'finger-four' formation. As briefed; after takeoff I crossed-under from left to right of Lead Aircraft to join in normal fingertip on Whiskey Lead's right. Whiskey Lead began closing on the Victor element ahead. While maintaining position; I experienced significant wake vortices from preceding 60-odd aircraft. I was moved above Whiskey Lead and briefly lost sight. I deconflicted turning away and descending from the element. I heard 'Tail' (the last aircraft in our formation traveling behind Whiskey element) ask Whiskey Lead if he had 'kissed me off' (released me from the formation) and I heard Whiskey lead respond 'no.' I visually reacquired Whiskey Lead to my left. 'Tail' asked would I rejoin and I replied 'yes.' I rejoined Whiskey Lead and proceeded uneventfully to ZZZ1 for landing as briefed. At no time did l either observe or experience any flight control issues during the flight; landing or taxi. I was unaware the aircraft had touched until after landing; when I exited the aircraft and observed damage to my rudder trim tab; which I pointed out to Whiskey Lead pilot. We called the NTSB and made a verbal report.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.