In article m,
Wizard of Draws wrote:

On 3/23/06 12:26 PM, in article
et, "Dudley Henriques"
wrote:

Yes, they do "bump" once in a while in the formation. There have been
numerous sheet metal "benders" through the years. Naturally, these are
wingtip hits laterally rather than nose hits :-) I remember one of these
occasions quite vividly during the 73 season.
The flow patterns in the diamond are unique to close proximity similar
aircraft. I say similar because in a close Diamond of dis-similar aircraft,
the flow patterns would not be as predictable.
Tip vortices on the left and right wing positions in close tend to cause a
roll away from the opposite aircraft and have to be countered. You can
really feel this as you get in close.
Lead and the slot position have their trim affected as the slot sticks his
nose in where it should be. Lead can actually "feel" the slot in position
and knows by his trim change if the slot slides out too far. The trim change
is nose down for the lead and nose up for the slot, again caused by the flow
patterns.
It's not nearly as smooth in the Diamond as it looks to you from the ground.
There is a lot of movement going on in the formation, especially through
rough air. It takes intense concentration to hold position.
On the cross over question. They use pre-selected hack and checkpoints
briefed by photo recon before the show as well as radio calls when visual.
Timing on the high show bomb burst is a hack call down from lead to the
split S pull on his cadence. There is a visual call by each opposing
aircraft (lead/slot) (left/right wings) and adjustments made during the
downside recovery for altitude and airspeed to seek co-cross at show center.
Naturally, both sides of the runway are used. It saves a hell of a lot of
sheet metal work after the show :-)
Hope this helps a bit.
Dudley Henriques


My question for a long time has been, how do they keep their speed
synchronized so well so they can maintain such tight formations? It seems to
me that small variations would have to creep into their engines, requiring
micro adjustments to the throttle settings in flight. Do they have that
available, or are the engines so well maintained that X% of thrust on Bird1
is _exactly_ the same as every other?

In tight formation you don't even LOOK inside the cockpit! you have
reference points on the other aircraft that you keep in line and make
adjustments with throttle -- very often macro adjustments, rather than
micro. All flights are flow according to the briefing -- and -- all
flights are debriefed ASAP.

Get hold of the T-34 Association's formation manual to help get up to
speed.