Dead Stick Landing

[Jim Meade]

I've been curious how the CTSW would handle with the engine off. In 40 years of flying, I've never shut an engine off in flight except in twins - and then I always had one on. I've done plenty of zero thrust or idle but no engine out.

 

So, the other day I took off and flew to a local non-towered airport that was pretty quiet and had two good runways, one right into the prevailing wind which was about 10G15 as I recall.

 

At 2500 over the airport, I did a couple of mag checks. Very straightforward. So, I pulled the throttle to idle and shut it off. It took about 5 seconds more or less for the engine to stop. The propeller stopped, too. For all the following attempts the propeller always stopped. On a couple of occasions the prop would turn a blade, but that was it.

 

I gave it a few seconds and restarted. No problem. Start at idle and advance the throttle. No choke used. Engine came right on and right on up to speed.

 

The next time, I decided to do a dead stick landing. I entered a normal downwind, set up my speeds and flaps as usual, and then pulled the throttle to idle and turned the key off.

 

I am a commercial glider pilot and CFI-G so I wasn't worried about flying with no engine. I'm current in gliders. I had gone out a month or so ago and done some soaring at idle in the CTSW

 

My pattern altitude was about 1,000 feet (higher than I usually fly but, hey!...). on downwind, I slowed down and used 15° flaps. I left them on for most of the landings. I did three dead stick landings on the favored runway, then went over and did two or three more on the croswind runway. 60° crosswind.

 

The plane handled in a very straightforward manner. I pitched for 65 kias for most of the pattern, then slowed on final and landed about like I always do. I didn't look at the ASI so hesitate to say what my touchdown speed was.

 

One one landing, I was pretty high and on final went to 30° flaps. The plan gives the impression of a pretty steep descent when you are on those flaps with no forward propulsion at all. One another landing, I turned the engine back on on short final. I'm not sure why I did that and am not suggesting it was a good idea. Making a big change that close to the runway is not something I'd advocate, so I won't do it again. I only say it because it was a non-event to get the engine back on at idle and did not generate any unusual control or pitch attitudes. Again, I will not make this big a change close to the runway again.

 

There are two lightly used, good airports not too far from each other. One of these days, I'm going to get up pretty high, maybe even 10k, and shut the engine off and see what the glide ratio turns out to be.

 

The longest I had the engine off was the time it took to glide a normal pattern from 1,000k at downwind to landing. What would that be, a couple of minutes? In every case the engine shut off quickly and smoothly and started immediately. I'm burning 91 octane mogas. The plane is just out of condition inspection, so has new plugs and everything is working smoothly to the best of my knowledge.

 

I am posting this experience for the benefit of any who may be curious as to how the airplane handled in one situation. I am not advocating that you go out and do this. If you do want some experience, it might be good to go with a CFI who has some training and experience.

 

 

 

 

 

[wlfpckrs]

I was curious about the glide ratio, since there has been some recent discussion on it.

[Runtoeat]

Jim, did you feel that the plane changed altitude or the pitch attitude changed when you temporaily started the engine while on short final? I'm asking because I recall that a stopped propellor causes less drag than a propellor tuning with the engine at idle.

[Jim Meade]

My impression is there was a slight tendency for the nose to rise with the engine started at idle. It was not very strong and was no problem at all in control.

 

I did not do anything deliberate about glide ratio, but will report what I find when I get a chance to esperiment.. If you have suggestions on how to do a reasonably objective test, by all means let me know. I have a few ideas and a local friend has offered some useful suggestions. I'll probably ask him to fly chase plane when I do my glide test. He's busy for a few weeks so this may not be for a while. The plane has a Dynon 100, 120 and Garmin 496 plus I have Foreflight on the iPad for instrumentation. There is an auto pilot and I'll probably engage it to reduce excursions and enhance stability if it makes sense.

 

 

[Runtoeat]

Interesting, thanks.

[BMcCand - N248CT]

On a GPS396, if you put data fields in the 4 corners of the moving map, you can then change the fields.I put Glide Ratio on bottom left, and glide to target on bottom right. Select target airport , Direct Toand you can see if Garmin thinks you will make it. I've seen 11:1 in my CTSW with engine idling.CTLS POI says to expect 8.5 (I think)I have not done the shutdown experiment.I imagine you have similar data fields with a 496.

[Jim Meade]

Bill, thanks for that tip. I'll certainly use it.

[Russell Croman]

Glide ratio measurements are very hard to do with any accuracy. To compensate for wind, you have to do at least two measurements with headings 180 degrees apart (preferably four measurements 90 degrees apart, unless you know the exact direction of the wind). And these have to be done starting from the same altitude, and in the same air mass... same wind, lift, sink, etc. Not easily achievable even on the calmest of days (or nights)... the atmosphere is constantly in motion.

 

You might be able to get within +/- 1 point of glide ratio, but I'd be surprised if you could get a repeatable measurement more precise than that. However, that's probably close enough for practical purposes... if a fraction of a point makes or breaks your emergency landing, you've probably picked the wrong LZ.

 

I have seen a good method for getting fairly accurate relative glide ratio measurements: start two aircraft at the same altitude, heading, and airspeed... cut power on both at the same time, pitch each for what you think best glide is, and see which one glides further. I fly paragliders as my other hobby, and this is the actual method that manufacturers use to see if they have built a better wing... they fly the new and the old models side by side with pilots coordinating so they give the same control inputs.

 

This would probably be a total hoot to do with two CTs.

 

-Russ

[Jim Meade]

You know, I could actually do that! There is another CTSW on the same field and the pilot might just be curious enough to try it. We have flown formation before for several hours so we're not afraid of each other. But......just forgot! I have to get him to turn his engine off. Hmmmm.........

 

I've been getting some input from glider forum people on how gliders determine best L/D, so I'll throw all this in the hopper and see what I can come up with that I'm comfortable with for my application. I'm very interested in the different discussion of best glide speed and best L/D. Not so we can stretch it...God Forbid!....but so we know if we are stretching it. Thanks for the tip.