Post by Tom Goodrick on Dec 22, 2010 22:02:42 GMT -5
Yesterday I worked on the Cessna 510 Mustang. We kicked this around a couple years ago. I have a good model on my Dell desktop. But I can't transfer files to my laptop so I downloaded a copy of John Loney's Mustang and began developing the FD from a fresh start. His FD was totally off, some combination of other jet parameters, the Beech Premier is named in his files. I got it fixed pretty well and then was looking at the stall numbers and got bored so I decided to try out some ideas for stall dynamics. I wanted a notable break if someone got slow enough to slip into a deep stall.
This is not a realistic characteristic of the Mustang. Cessna went to great pains to make the plane avoid a deep stall. They gave it ventral fins to push the nose down instead of installing a stick-pusher as normally required. I worked with the lift curve in Table 404 to get the right max CL and a fairly sharp drop. I worked with the pitching moment curve for the whole aircraft in table 473 making various shapes after the stall. When stall occurs, the wing loses lift in various parts during the process. This makes the pitching moment a little strange. I ended up with a zig zag, down and up beyond where the stall occurs. Doing careful slow approaches to a stall everything seemed okay until it reached a point just below the stall speed where the angle of attack would shoot up to 50 degrees and the plane would then settle back and then flip into a short spin through a full turn and then it would recover and go into another approach to stall unless the pilot reacted. Recovery was not hard.
Today I checked the national weather and found snow and cold in southern Illinois and figured I could make a quick dash from there to sunny and relatively warm (55F) Huntsville. I started with an Aero Commander 500 cruising at 9,000 ft. I was in icy clouds. (They would have been icy at -6C with light snow if FS allowed ice in RW.) I decided no real flight could be conducted that way. Even at 11,000 ft I was going through cloud tops.
So I went back to Springfield with its mild snow storm and took off in the Mustang at MTOW. There were several times when 95 knot winds switched direction more than 90 degrees and the plane rocked violently. At 20,000 ft I looked away at TV a moment and looked back to find the plane was spinning down toward the clouds below. I recovered and resumed the climb at about 15,000 ft. I leveled at 27,000 ft for a cruise direct to HSV. There were several wind shifts that rocked the plane enroute. The speed stayed new 95 knots but the direction came from all points at various times but mostly it pushed me south. I was descending from 8000 ft for 3000 ft about 15 nm from HSV when I looked away at TV a minute. When I looked back the plane's nose struck the ground about 12 nm from HSV.
Guess I have to quit watching TV while flying.
This is not a realistic characteristic of the Mustang. Cessna went to great pains to make the plane avoid a deep stall. They gave it ventral fins to push the nose down instead of installing a stick-pusher as normally required. I worked with the lift curve in Table 404 to get the right max CL and a fairly sharp drop. I worked with the pitching moment curve for the whole aircraft in table 473 making various shapes after the stall. When stall occurs, the wing loses lift in various parts during the process. This makes the pitching moment a little strange. I ended up with a zig zag, down and up beyond where the stall occurs. Doing careful slow approaches to a stall everything seemed okay until it reached a point just below the stall speed where the angle of attack would shoot up to 50 degrees and the plane would then settle back and then flip into a short spin through a full turn and then it would recover and go into another approach to stall unless the pilot reacted. Recovery was not hard.
Today I checked the national weather and found snow and cold in southern Illinois and figured I could make a quick dash from there to sunny and relatively warm (55F) Huntsville. I started with an Aero Commander 500 cruising at 9,000 ft. I was in icy clouds. (They would have been icy at -6C with light snow if FS allowed ice in RW.) I decided no real flight could be conducted that way. Even at 11,000 ft I was going through cloud tops.
So I went back to Springfield with its mild snow storm and took off in the Mustang at MTOW. There were several times when 95 knot winds switched direction more than 90 degrees and the plane rocked violently. At 20,000 ft I looked away at TV a moment and looked back to find the plane was spinning down toward the clouds below. I recovered and resumed the climb at about 15,000 ft. I leveled at 27,000 ft for a cruise direct to HSV. There were several wind shifts that rocked the plane enroute. The speed stayed new 95 knots but the direction came from all points at various times but mostly it pushed me south. I was descending from 8000 ft for 3000 ft about 15 nm from HSV when I looked away at TV a minute. When I looked back the plane's nose struck the ground about 12 nm from HSV.
Guess I have to quit watching TV while flying.