Crossed Controls

[hanspetter]

There have been discussions on the use of crossed controls or sideslipping to make an aircraft sink faster. Basically, if you kick rudder in one direction and turn the yoke in the opposite direction you end up going straight but you add a lot of drag that will help you lose altitude faster.

I've tried a few tests in FS, Flight Unlimited and X-Plane and it seems that crossed controls don't really effect much if anything at all. I even tried the Real Air Cessna which is claimed to sideslip and stall more like the real aircraft. I saw no difference.

Provided flightsim aircraft don't sink faster with crossed controls this means that the flightmodels don't register the extra drag. Has anyone else studied this? A lot of us have tried crossed controls to get down into a steep valley and have thought it helped (because it should)...

[Tom Goodrick]

This depends in FS9 on what the settings are in the 1100 area of the .air file. In the Side Forces area of the 1100 section, set CY_beta to at least -0.652 for the Piper Cub. I have CY_dr = -0.0415 as well. There should also be a Cd_beta but I don't see one.

I have seen an effect but it takes a lot of aileron. It helps to do this when lined up with the runway before the deflections. Doing the maneuver over a straight road is also good. Try to track straight while sideslipping.

In my Aerobat, I set Cy_beta at -0.75 to help with tumbling. Get in a slow climb and hit full left rudder and full right aileron while jerking the stick back in the Aerobat. It is interesting. Turn on smoke for the replay.

[Tom Goodrick]

I setup a Flight starting at 90 KIAS at 1700 msl close to Runway 18L at KHSV. I could not see the end of the runway over the nose. I then flew a Cessna 172R, Alon Aircoupe and Piper J-3 Cub in for a landing. In the Cessna I slowed and dropped full flaps and then dived at the runway. I landed about 1/3 down the runway. The Aircoupe did not slip well (has no flaps). It was originally designed with no rudders but I added small, ineffective rudders as were added to the Alon version. It landed 1/2 way down the 10,000 ft runway. The Cub slipped so well the last 1/3 of the approach was in a simple glide to a stall landing on the numbers. The slip was no minor maneuver. Well into it I saw a pitch angle 35 degrees down, roll 45 degrees left and a sideslip 40 degrees right. That brought it down like an elevator.

I remember being taught real slips like that as a kid.

The Cub landed at 30 KIAS. The others were about twice as fast.

[Dave Evans bgak015]

The best thing about slipping a Cub ? It allowed me to see around that long nose and the back of the 6'2" instructor