Vyse vs. Vg

[LivinTheDream]

I had a theoretical question sticking in my mind for a while, haven't had the chance to run it by my instructor yet.

My thinking comes from my glider days years back, when we had two airspeeds, Min. Sink and Best Glide. Min Sink being the least amount of altitude loss over time (from producing most amount of Lift) and Best Glide being most amount of distance for altitude (Max L/D).

So let's say you're flying a Twin now and you lose an engine. Even at Vyse, max power on the operating engine, and a feathered inop, you're descending. Would you get the most distance out of the aircraft staying at Vyse or speeding up to Vg?

Maybe if I get some extra money I'll test it, but I'm curious what everyone thinks.

 

[NJP_MAN]

Tricky question. I would say eventually you'll hit your single engine ceiling and everything is fine and dandy I'm sure in your scenario, you have selected to be flying over terrain that is higher than your single engine ceiling or else this wouldn't be that fun of a question to ask. I'm interested in the answer

 

[whattauser]

The best distance will usually be obtained by turning directly away from the wind.

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[Dana]

Having no engine at all (glider) or one engine out, best distance will still be the same "best glide" speed (which will be very close to Vy; min sink speed close to Vx).

 

[LivinTheDream]

I'm sure in your scenario, you have selected to be flying over terrain that is higher than your single engine ceiling or else this wouldn't be that fun of a question to ask.

The Seminole I got my MEL in couldn't climb on one engine, even in the middle of Missouri winter. And the Baron I'm flying now can't climb at Vyse and the inop windmilling. Hence why this question came to mind.

The best distance will usually be obtained by turning directly away from the wind.

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Of course, but what if there's no wind?

 

[whattauser]

Of course, but what if there's no wind?

You would need to refer to the single engine drift-down charts for your weight and conditions. Absent that, an altitude and weight-adjusted Vyse is the answer.

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[PPC1052]

The Seminole I got my MEL in couldn't climb on one engine, even in the middle of Missouri winter. And the Baron I'm flying now can't climb at Vyse and the inop windmilling. Hence why this question came to mind.



Of course, but what if there's no wind?

Just buy a king air and you'll be fine.

 

[oldShar]

Of course, but what if there's no wind?

??? Where in the world does That Ever happen????

((Capt Murphy would have been drummed out of the Air Force if he ever proposed such an anomaly))

 

[hindsight2020]

The Seminole I got my MEL in couldn't climb on one engine, even in the middle of Missouri winter. And the Baron I'm flying now can't climb at Vyse and the inop windmilling. Hence why this question came to mind.

The seminole I did my ATP in would climb OEI with two up front and full fuel in the middle of the TX summer (95 deg and 80% humidity, god awful density alt).
Just throwing another data point out there.

 

[LivinTheDream]

You would need to refer to the single engine drift-down charts for your weight and conditions. Absent that, an altitude and weight-adjusted Vyse is the answer.

And with that I learned that Single Engine emergencies are handled differently in jets than in piston engines.

??? Where in the world does That Ever happen????

In a theoretical situation inside our minds. Most often to explain Min Sink and Best L/D speeds to new Glider pilots.

The seminole I did my ATP in would climb OEI with two up front and full fuel in the middle of the TX summer (95 deg and 80% humidity, god awful density alt).
Just throwing another data point out there.

Each Piston Twin seems to be different, which is why it'd be nice to know my original question.

 

[whattauser]

And with that I learned that Single Engine emergencies are handled differently in jets than in piston engines.

Not just jets, but a good pilot is always learning.

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[hindsight2020]

Personally I'm glad the ME requirement to get into the regionals is nill. I consider part 23 twins a substantial negative transfer to the flying behavior and abnormal operation handling of part 25 turbines. An aircraft with no requirement to show positive OEI performance on takeoff has no place in the training of part 25 twin pilots imo. Beyond a "gee-whiz look how close I can get to the edge with propellers Bobby Hoover", it's ballwash training.

Had I done any of what I had to demonstrate in the seminole for the ATP ride in a Guppy, let alone a true heavy multi like the BUFF, I would have morted right ricky tick and taken a lot of people with me. That to me is borderline derelict from a flight training "best practices" POV. But whatever, I got the ticket, so good luck to all. Let all the line CAs and the training department re-teach the wheel at their own expense. I've stated my objection, I sleep with a clear conscience. Not all baby turtles make it out to the ocean type of thing.

 

[whattauser]

Personally I'm glad the ME requirement to get into the regionals is nill. I consider part 23 twins a substantial negative transfer to the flying behavior and abnormal operation handling of part 25 turbines. An aircraft with no requirement to show positive OEI performance on takeoff has no place in the training of part 25 twin pilots imo. Beyond a "gee-whiz look how close I can get to the edge with propellers Bobby Hoover", it's ballwash training.

Had I done any of what I had to demonstrate in the seminole for the ATP ride in a Guppy, let alone a true heavy multi like the BUFF, I would have morted right ricky tick and taken a lot of people with me. That to me is borderline derelict from a flight training "best practices" POV. But whatever, I got the ticket, so good luck to all. Let all the line CAs and the training department re-teach the wheel at their own expense. I've stated my objection, I sleep with a clear conscience. Not all baby turtles make it out to the ocean type of thing.

The handling of the part 23 twin I flew at FL450 was quite similar to the part 25 one, but I see your point. With enough time spent exploring the different characteristics of a large Delta in performance, I think the training can be done while mitigating negative transference.

 

[hindsight2020]

The handling of the part 23 twin I flew at FL450 was quite similar to the part 25 one, but I see your point. With enough time spent exploring the different characteristics of a large Delta in performance, I think the training can be done while mitigating negative transference.

Agreed.

 

[PPC1052]

I consider part 23 twins a substantial negative transfer to the flying behavior and abnormal operation handling of part 25 turbines. An aircraft with no requirement to show positive OEI performance on takeoff has no place in the training of part 25 twin pilots imo.

On the OEI takeoff accident I have recently been involved with, this is absolutely dead bang on accurate.

Not all baby turtles make it out to the ocean type of thing.

LOL!!! This appeals to my dark sense of humor.