Originally Posted by
chevvron
Years later, I experienced gliding in a Hunter T7.
I was up with the late lightningmate, (not to be confused with Lightning Mate who is still with is on this forum) one of Farnborough's ace test pilots. He pulled the throttle at about 16,000ft just south west of Greenham Common and asked Boscombe for a '1 in 1' to their main runway. Pullng the speed back to 250 kt indicated gave rod of 500ft/mile. Boscombe vectored us towards their centreline giving us range from touchdown checks and when our height numerically equalled range eg 11,000ft at 11nm, he dropped flaps and gear and increased rod to 1,000ft/mile (1 in 1, get it?) and we continued at this rate of descent until it was time to flare for a touch and go.
Chevvron,
If I may make a few technical corrections to what you have said (and lightningmate was a good friend and colleague of mine): The normal gliding speed in the Hunter with undercarriage and flaps up was (and still is!) 210 KIAS which gave a range of 2nm/1000 ft altitude loss (4.7 deg glide angle). For practise, 2 notches of flap (23 deg) was lowered and 5500 RPM set (in a T Mk7) to simulate windmilling engine drag. When the '1 in 1' slope was intercepted (1nm/1000 ft, 9.34 deg glide angle) the undercarriage was lowered and 210 KIAS maintained by lowering the nose. Airspeed was then varied between 180 and 240 KIAS to maintain the '1 in 1' slope. At a visually judged point (typically between 500 and 1000 ft above touchdown) the flaps were lowered fully to reduce speed to 170 KIAS for commencing the flare. If it was a practise the power would be reduced at the flare to 4500 RPM (to protect the engine surge margins for the tough-and-go or go-around and maintain a short engine spool up time).
This pattern worked because of the drag characteristics of the Hunter with the undercarriage down at 210 KIAS. It was initially used also in the Hawk T1 when it entered service and it worked with idling thrust but would not with windmilling drag, and hence the radar forced landing pattern was developed. This pattern will work with any drag polar so can be used on most types.
Returning to where this thread started, if a high drag aircraft is gliding with a steep angle then a given angular change of glide angle will equate to a smaller distance over the ground than for a low drag aircraft with a shallower glide angle. Therefore, it is easier to judge the touchdown point in a high drag aircraft. However, the probability of not having sufficient energy to make an airfield following an engine failure is greater with high drag.