Pilot reported departing airport during fly-in and was overtaken by unreported fly-by aircraft.

Narrative:

A temporary tower was in use. I noticed the flight of 9 on a downwind and I assumed they were preparing to perform a fly-by of runway xy. I was cleared for takeoff behind another flight of 3 aircraft. I did not see the location of the previous flight of 9; and departed as instructed. I continued runway heading as I watched the previously departed flight of three and as I climbed through about 1;000 feet AGL I was passed on my left side very closely by the flight of 9. At no time did the tower advise either me or the flight of 9 of the traffic.in retrospect; this was sort of a perfect storm for a conflict. My aircraft is slow (70 KTS); but climbs very rapidly (1;500+ FPM). The flight was probably cruising about 140 KTS and wouldn't have expected slower traffic to suddenly climb into their flight path. I can't see traffic above and behind me; especially with 70 KTS of overtake.tower is manned by volunteers who do a superb job of handling lots of traffic; but unfamiliarity and distraction caused a loss of situational awareness. I would suggest the following procedural change and other fly-ins where there is a fly-by pattern that lies over the top of the departing runway: that departing traffic be restricted in altitude on departure; say 800 AGL until clear of the airport and fly-by traffic be restricted to 1;300 AGL while overflying the runway.

Original NASA ASRS Text

Title: Pilot reported departing airport during fly-in and was overtaken by unreported fly-by aircraft.

Narrative: A temporary tower was in use. I noticed the flight of 9 on a downwind and I assumed they were preparing to perform a fly-by of Runway XY. I was cleared for takeoff behind another flight of 3 aircraft. I did not see the location of the previous flight of 9; and departed as instructed. I continued runway heading as I watched the previously departed flight of three and as I climbed through about 1;000 feet AGL I was passed on my left side very closely by the flight of 9. At no time did the Tower advise either me or the flight of 9 of the traffic.In retrospect; this was sort of a perfect storm for a conflict. My aircraft is slow (70 KTS); but climbs very rapidly (1;500+ FPM). The flight was probably cruising about 140 KTS and wouldn't have expected slower traffic to suddenly climb into their flight path. I can't see traffic above and behind me; especially with 70 KTS of overtake.Tower is manned by volunteers who do a superb job of handling lots of traffic; but unfamiliarity and distraction caused a loss of situational awareness. I would suggest the following procedural change and other fly-ins where there is a fly-by pattern that lies over the top of the departing runway: That departing traffic be restricted in altitude on departure; say 800 AGL until clear of the airport and fly-by traffic be restricted to 1;300 AGL while overflying the runway.

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.

Attributes
ACN	1463282
Time
Date	201707
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Small Aircraft
Operating Under FAR Part	Part 91
Flight Phase	Initial Climb
Aircraft 2
Make Model Name	Small Aircraft
Operating Under FAR Part	Part 91
Flight Phase	Initial Approach
Person 1
Function	Single Pilot Pilot Flying
Qualification	Flight Crew Multiengine Flight Crew Instrument Flight Crew Flight Instructor Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 5 Flight Crew Total 19000 Flight Crew Type 270
Events
Anomaly	ATC Issue All Types Conflict NMAC
Miss Distance	Horizontal 100 Vertical 0