Originally Posted by
gums
Salute!
...I do not have my technical reports from 35 years ago that show the actual plots of stick force versus "commanded" aircraft response.for the YF-16 and the FSD version. I soloed in the original Block 1 ( less than 100 delivered, and was lucky to fly serial numbers like 001, 007. 013 and so forth), and instructed in the Block 5, 10 and 15.
The stick did not move in the Block 1 - it was like a pipe in concrete. We flew with it using wrist pressure. The 1/8 inch movement in the Block 5 and later was not apparent to this old fart, but it made the brass happy and might have helped a small amount in formation flying, although breakout force was the same - about a pound or slightly less for both pitch and roll
Our feedback was visual and seat of pants gee and body rates from our innner ear gizmos. No problems. The forces were fairly linear after breakout, tho the roll had one "bend" in the plot. So 16 or 17 pounds of roll command resulted in max of 300 degrees per second and 30-34 pounds of aft stick commanded 9 gees biased by AoA.higher than 15 degrees.
As wth the 'bus, we did not have any problems with old or new pilots, and like the 'bus we could not see or feel what the other dude was doing with the stick. Our pressure versus command was damned near a straight line, so 16 pounds aft stick was about a 4 gee command. Gums sends...
Your memory seems to be doing better than your teeth there Gums. At some point a 2 step pitch demand was added to the DFCS (15DFCS004), along with an S bend like 3 step lateral demand (16DFCS006). No idea at what block. The Airbus gains were of a 2 step form and varying with configuration, with envelope protection and landing phase varying that, but that is going back about 15 years. Force-rate values for the 16 were per your memory.
This may be off topic or it is right in the middle, the question was whether collectively the industry is losing skills through the use of automation, and lack of hand flying, or whether that really makes much difference in FBW aircraft. The response to the MCAS bingles appears to include regulator calls for more hands on flying, which may be the magic solution, or it may paradoxically just add more loss of S.A. events. Your comment that the cues that you are using are not from the FCS, but are from the instrumentation and performance of the aircraft, which is notable. Dropping out the AP and using the SSC puts the driver into the control loop irrespective of force feel of the control systems, which would then suggest that the in loop vs out of loop differences are related to the cognitive tracking task that the driver gets to do, being active or passive in the loop, feel being of less importance. Then the issue is whether the cognitive task demand of the tracking task overall detracts from the bandwidth available for S.A. more or less than it benefits it. That is not a trivial concern, as the industry plants aircraft boneyards off the end of runways routinely from the crew being so preoccupied with getting on the ground with hand flying that they end up landing 7000' down a 10,000' runway. ET and JT feature in that sort of deal, but so do US, French, German aircraft, so loss of S.A. is agnostic or just endemic.
cheers.