Ian;
Thanks for the A4 pic.
When living in Lower Hutt in 1990/1991, I had the opportunity to fly to Hamilton for the day. After my work was done, a colleague and I went to the airport, had a tea and a biscuit on the outdoor patio (knee high white picket fence between us and the apron) where we were able to watch the flew-in-for-the-day NZAF repair crew figuring out why an A4 was blowing smoke rings whilst flying the day before (and made an emergency landing at Hamilton).
The ground crew had plans on the apron, held down by weights on each corner, and were scratching their heads while an A4 sat close by, running, with pilot aboard. Engine would be throttled up, back down again, and more head scratching.
Eventually one of the ground crew gave the pilot a wave to go and fly, which the pilot did. After the second wave.
He went to the end of the runway, way down behind trees. After what seemed like 5 minutes of full throttle (obviously brakes on), the little A4 rocketed down the runway, became airborne and flew off to the right and behind the terminal. Ground crew just stood on the apron. After a minute or two the little A4 flew over the terminal building at a very low/fast altitude; no smoke rings evident, so the ground crew removed the plans from the apron, hopped into their aircraft and flew off to places unknown.
What a nice way to spend an hour on a beautiful sunny day!