339A
Well Known Member
Intentionally that is…. Well this is something I have wanted to do for a while now. It was an absolutely perfect Colorado day, wind calm, about 45 degrees out, who needs to go to work on a day like this? It’s a far better day for flying than working. Off to the airport I go with a plan in mind.
A friend sent me this video of an RV4 doing a power off descent and landing from about 8500 feet. This is something I’ve contemplated and decided it was time to do. For my purpose today I would fly over to Limon (LIC) and perform my engine out glide test. Upon arriving over the airport at 9500 feet, I slowed down to slow flight speed and practiced. The 9A is pretty easy to handle at 70 MPH, a few minutes of this and I was ready. Everything was good so I decided to pull the red knob and throttle all the way back. The engine RPM finally dropped off and the EIS was not a happy camper, as all manner of alarms came in. The engine continued to windmill and I found this to be annoying. Keeping a close eye on my airspeed I pulled back on the stick in an attempt to stop the prop (Catto three bladed fixed). It finally stopped and stayed that way. I then tried various airspeeds and recorded my vertical descent speeds. These tests were done with no flaps so I’m sure the numbers will change when flaps are added.
70 MPH equals 400 FPM
75 MPH equals 500 FPM
80 MPH equals 600 FPM
85 MPH equals 750 FPM
90 MPH equals 1000 FPM
About 2000 feet AGL I pushed the throttle and mixture back in, mags on and hit the starter. She fired right up and I climbed back to 9500 and did it all over again. I did this three times with the same results each time. My next step will be to actually dead stick the airplane. But I was quite happy with my efforts for the day. It’s amazing how much different things sound once the engine is off. At 70 MPH it was fairly quiet, but as the speed increases the wind noise goes up significantly. Something we just don’t normally hear with the engine running.
I’m glad I did this, and now I have some real experience/numbers if the engine does quit. Anyone who is comfortable flying their plane should give this a try and find out some useful numbers. The hardest part is going to be discerning at what point to turn for the field. In my attempts today I would have been quite high on final, but I plan to work on that and come up with a better technique for making the runway/field from about 1000 feet.
A friend sent me this video of an RV4 doing a power off descent and landing from about 8500 feet. This is something I’ve contemplated and decided it was time to do. For my purpose today I would fly over to Limon (LIC) and perform my engine out glide test. Upon arriving over the airport at 9500 feet, I slowed down to slow flight speed and practiced. The 9A is pretty easy to handle at 70 MPH, a few minutes of this and I was ready. Everything was good so I decided to pull the red knob and throttle all the way back. The engine RPM finally dropped off and the EIS was not a happy camper, as all manner of alarms came in. The engine continued to windmill and I found this to be annoying. Keeping a close eye on my airspeed I pulled back on the stick in an attempt to stop the prop (Catto three bladed fixed). It finally stopped and stayed that way. I then tried various airspeeds and recorded my vertical descent speeds. These tests were done with no flaps so I’m sure the numbers will change when flaps are added.
70 MPH equals 400 FPM
75 MPH equals 500 FPM
80 MPH equals 600 FPM
85 MPH equals 750 FPM
90 MPH equals 1000 FPM
About 2000 feet AGL I pushed the throttle and mixture back in, mags on and hit the starter. She fired right up and I climbed back to 9500 and did it all over again. I did this three times with the same results each time. My next step will be to actually dead stick the airplane. But I was quite happy with my efforts for the day. It’s amazing how much different things sound once the engine is off. At 70 MPH it was fairly quiet, but as the speed increases the wind noise goes up significantly. Something we just don’t normally hear with the engine running.
I’m glad I did this, and now I have some real experience/numbers if the engine does quit. Anyone who is comfortable flying their plane should give this a try and find out some useful numbers. The hardest part is going to be discerning at what point to turn for the field. In my attempts today I would have been quite high on final, but I plan to work on that and come up with a better technique for making the runway/field from about 1000 feet.
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