Olem, Kaye's propeller 'remark' was just that, an impromptu remark in the face of cameras, and never intended to be a serious theory. I dont think it dawned on Tom or Carr that it would get the airplay it did! Tom can speak for himself but that is my understanding (and belief based on Tom's explanation to me, and I believe him! 
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Well that's very good to know because I respect Kaye's work a lot!
Cooper's descent that night was probably a nearly blind descent, based on the weather, his lack of control of the chute, and the altitude where it starts.
This is a question for Robert, who appears to be this board's resident parachutist, but there a few things I'm wondering about the jump itself. If he had pulled his chute immediately after jumping at that height, it would have taken him what, ten minutes to fall to earth? In that time, in the high winds that were alleged that night, how far would he expect to drift away from the spot directly below him when he first jumped out? Are we talking miles of drift? A few hundred yards?
It's my understanding that most sport parachutists will release the chute at around 1,000 feet so they aren't floating around in the sky for 15 minutes, but if you were in DB's situation with solid cloud cover below you and an uncertain altitude (I'm assuming DB didn't really know how high they were, he just trusted the crew to follow his instructions), would you risk a sustained free fall or would you release your chute almost immediately just to be on the safe side?
Also, being a parachutist, can you "feel" your altitude? What I mean is, if you were in DB's shoes standing on the stairs, could you tell the difference in 5,000ft-10,000ft-15,000 ft in the middle of a cloudy storm with almost zero visibility.
Again, let me be brutally honest! Smile... 
The issue of the weather is debated? Smile R99 thinks the weather is a simple matter and a closed book. I guess it is fair to say 'there are myths and facts about the weather that night'. So, depending on whatever WX scenario you bring into play, the drop account changes accordingly. High winds? That is debated. R99 will point out the WX stats are plain and simple and do not allow for the high winds some insist was the case. When all of this was discussed endlessly at Dropzone, I think drift was finally placed at somewhere around 4 miles? A dead-fall scenario happens in seconds (60-80)? Time to ground depends on time of opening, winds, drift vs. free fall, etc. ...
OMC,
There are a number of people on this thread whose parachuting experience is VASTLY greater than mine. And I will defer to them on all parachuting and skydiving questions. Perhaps 377, who is also an attorney, will comment on the "feel" question about altitude.
When Cooper jumped, the airliner was doing about 225 MPH True Airspeed (which is with respect to the air surrounding it) and at about 10,000 feet Above Sea Level (as specified by Cooper although he didn't say "ASL"). The airliner was almost certainly very close to the Columbia River, which is just a few feet ASL in the Portland area. Portland International Airport is adjacent to the Columbia River and its altitude is listed as 30 feet ASL. So Cooper had slightly less than 10,000 feet of terrain clearance below him when he jumped.
If Cooper successfully deployed the canopy immediately after separating from the airliner, he would have done so at about the top speed for which the canopy was rated (actually, 225 MPH may well have been higher than its maximum rated opening speed) and Cooper would have received the highest opening shock possible under the circumstances. As Georger has pointed out above, when last seen Cooper was tying the approximately 25 pound money bag around his waist (as opposed to attaching it to the parachute harness) and could have received up to a 250 pound jerk on his spine from the money bag alone and that would have been bad news.
But if Cooper did get an open canopy successfully at 10,000 feet and 225 MPH, he would have descended at about 1200 feet per minute and drifted to the northeast and towards higher terrain. The aft stairs placard, which separated from the airliner a few minutes before Cooper jumped, was found at an elevation of about 1500 feet ASL. So Cooper could have had about 7 or 8 minutes of descent time. How far he travelled horizontally during that descent depends on the winds from the surface to 10,000 feet.
And as Georger has also pointed out above, the winds and other weather for the Portland area during the time the airliner was passing through is a matter of disagreement. The actual measured and recorded weather that evening does not support the idea of a violent storm. Nevertheless, some people claim there was a storm.
When Cooper jumped, he was above an overcast and there were several cloud layers below the overcast. So if he decided to free fall to a lower altitude before opening, there is a high probability that he would have become disoriented (he had no horizontal or other references) and started tumbling with further disorientation. And if he was a no-pull, he would have been on the ground (and dead) about 40 to 60 seconds after leaving the airliner.
Did Cooper separate from the money bag during the descent? At the present time, no one can prove this point either way. But I suspect, based on a number of factors including where the money was found and its elevation above sea level, that Cooper and the bag stayed together all the way down. Keep in mind that those shroud line have a strength of about 550 pounds each. So if Cooper was a former Boy Scout and paid attention during his knot tying training, there is a good chance he retained that money bag.
