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HomeHomeDiscussionsDiscussionsiFly GPS for An...iFly GPS for An...Active Glide RatioActive Glide Ratio
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9/13/2021 3:40 PM
 

Don: you're practically using my copyrighted (no, not really) saying that "an imperfect something, is better than a perfect nothing".  We just need something to give us more data, quickly, in an engine-out situation.  It doesn't have to be, and can't be, 100% accurate.

BUT... if you DID want to make it better in version 2.0 of the glide ring, you would use the actual current glide ratio as you are descending -- instead of using the ratio that you inputted for the aircraft (which is static, and maybe optimistic).  The rub is when to use which?  Obviously, in level or climbing flight, you need to use the inputted glide ratio.  If descending: how does iFly know whether you're making a power-on descent or a power-off descent?  The only surefire way is if you've told it so in some way.  For instance, if you hit the exclamation point button in NRST.  But being that that requires extra button pushes, maybe the glide ring feature can include another way that's easier to say "I'm in a power-off glide right now".


Powrachute PC 2000; Aventura II; Cherokee 180
 
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9/14/2021 9:16 AM
 

Don, Hook,et al:

Since we are discussing engine failure procedures tha may get us to a safe landing spot...not necessarily an airport...I thought I  should share my experiances with 3 engine failures in my 8,000 hours. Most of these were in the last 3,000 hours. Two were sucked exhaust valves and one where the engne just fragmented. Actual cause was not determined by the Jabiru engine manufacturer.

I am in Sothern California and we have several dry lakes on which to practice actual engine off landings.

My group f flyers set up traffic cones at the touch down point and small flags at 100 foot intervals before and after the touch down target.

We climb to 1000 AGL and halfway on down wnd the engine is shut down. The flags let us know how short or long we are from the touch down target. We can also practice the "deadly turnback" procedure. These sessions build confidence so there is minimal panic when the engine goes silent.

This practice has paid off in my three actual engne failures two of which were on an airport and one off airport. No damage in each.

 In practice sessions I adjusted pitch to minimize descent rate and use that IAS in my susequent engine out landings. However, that speed was just a close proximation of the best speed for the actual conditions. For my aircraft that IAS is 55-60 MPH.

I fly the Idaho back country each year in the Johnson Creek area where an engine failure will most likely put you in the trees or in a stream bed in a deep canyon. In that case I just have to remember on the way down that the airplane will be the property of the insurance compay and my job is to survive.

In our tests for private or commercial tickets an instructor may pull to an idle to simulate an engine failure. However, your glide with the prop idling is better then when actually dead. You can clearly see this if you let off the brakes while on the ground. The airplane will move forward so there is some thrust. So glide range is a bit better at idle.

John M

 

 

 
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9/15/2021 9:11 AM
 

Don:

IFLY also has a handy feature that lets you insert waypoints anywhere on your chart.

So if you are flying on one of your usual trips and notice an off airport spot that you could safely use in the event of a silent engine, you can mark that spot for future reference in an emergency. That should help eliminate searching for a good spot while puckered.

John M

 
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10/4/2021 9:38 AM
 

If you are monitoring this thread I can assume you want the best outcome when your engine goes silent. I would like to recommend a book I got from Kindle.

Engine Survival Tactics by Nate Jeros  an ex F16 pilot who now flies a Bonanza. It outlines everything we need to know for the best outcome.

As an example: I had a hard time understanding why weight didn't change the glide ratio. He explains that if your plane is heavily loaded the glide ratio will be the same but your speed will need to be higher.  So you will touch down at the SAME spot but you will do so SOONER. He has guidlines for gliding in headwods or tailwinds and so much more.

You can download a sample 1st and if you like it you can download the entire book for about 8 bucks. Might be a read that could save your butt when it stops and you become a glider pilot. Oh, and he mentions many tips from glider pilots. He uses his Bonanza as a  reference in many examples but the principals also apply to most GA aircraft.

Finally I invite members who live in the Southern California area to join me at El Mirage dry Lake for engine out accuracy landing practicThis practice has been instrumental on allowing my three engine failures to come down safely with absolutely no panic. The vast expanse of this dry lake allows us to also practice the "deadly turnback" with plenty of room for any adjustments.

"I learned that danger is relative, and inexperience can be a magnifying glass." Charles A Lindberg

Fly safe.

John M

 
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10/7/2021 9:51 AM
 

While we wait for Glide Ratio I have discovered another tool to help with this.

Those of us with the Dynon or any avionics that will give angle of attack can use it to pitch the aircraft to the optimum AOA for best glide.

For my Avid Flyer MK4 that turns out to be when my Dynon AOA bar shows the green segment just below where it turns to yellow. This gives me 500 FPM descent at 55 MPH indicated which provides 9.68:1 glide ratio. 

Of course, you will need to make sure the AOA has been calibrated per the units instruction.

I have found that it is easy to control where the AOA bar is using pitch. 

This test was done with the engine at an idle and very little wind. 

I will fly out to the a dry lake in the high desert and actually shut down the engine to get some more realistic measurements.

I have found that best glide speed is between Vy and Vx. I will know better when I test on the desert.

John M

 

 
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HomeHomeDiscussionsDiscussionsiFly GPS for An...iFly GPS for An...Active Glide RatioActive Glide Ratio