Vy and Vyse

[MauleSkinner]

In regards to the chance of the airplane climbing below Vy or Vyse being 50/50, ummm, there is little to no chance involved. Depending on weight, CG, atmospheric conditions, and pilot technique, the airplane will already be in a condition to climb or not climb and it is up to the PIC to know the current conditions as to whether or not it will climb, it's not chance.

Now THAT's one of the best things I've seen in print since I read the "Safety Information" section of Beech POH's...

Know, BEFORE YOU TAKE THE ACTUAL RUNWAY (I think the emphasis is mine...I took this quote out of my Baron Powerpoint presentation), whether you can maintain control and climb out if you lose an engine while the gear is still down. It may be necessary to off-load some weight, or wait for more favorable temperatures.

The rest of the multi-engine flying portion of this document is pretty good, too, btw...I recommend it.

Fly safe!

David

 

[SBD]

" in the seminole its anywhere from 75-80s after you get cleaned up, initially, for level flight, and maybe 100fpm climb," My thoughts exactly. On a hot humid day where you are carrying some weight, the Seminole climbing while under Vyse or Vxse is really a crapshoot. The PIC's skill and knowledge will determine what events will play out. We can all calculate the best Single Engine Climb performance with the charts, but can you honestly tell me that you feel comfortable with that information. There have been times while performing a Vyse demo for students that we couldn't maintain altitude to save our lives.

 

[SBD]

This maybe a little off topic but since we are talking about Vxse and Vyse this might be a good place to ask this. On my MEI FAA ride the DPE asked me this scenario based question. After you rotate on the takeoff you lose an engine on let's say a 4000 foot runway and the only thing beyond the end of the runway is fields and grass. You are below Vxse and Vyse, do you
A) Continue on the climb and try to clean it up, feather, and return for landing?
or
B) Close the throttles and try to plant it straight ahead?

 

[SBD]

Fields grass and trees. Sorry.

 

[MauleSkinner]

This maybe a little off topic but since we are talking about Vxse and Vyse this might be a good place to ask this. On my MEI FAA ride the DPE asked me this scenario based question. After you rotate on the takeoff you lose an engine on let's say a 4000 foot runway and the only thing beyond the end of the runway is fields and grass. You are below Vxse and Vyse, do you
A) Continue on the climb and try to clean it up, feather, and return for landing?
or
B) Close the throttles and try to plant it straight ahead?

Here ya go...the answer is in there somewhere
http://forums.flightinfo.com/showthread.php?t=74653

 

[UndauntedFlyer]

Here ya go...the answer is in there somewhere
http://forums.flightinfo.com/showthread.php?t=74653

Another great post from MauleSkinner.:beer:

 

[greyhound]

I would first have to ask the following....

Why are you below VXse or VYse after 4000ft of rwy have passed?

The #1 priority after the airplane breaks ground is to let it accelerate to either one of those speeds. Takes 4-5 seconds at the most.

Now,(assuming I'm above those speeds) if I'm at a sea level field on a cool day, I would feather it/ climb to a safe altitude and turn back.

In the seminole with two people and full tanks I've gotten 500 feet per min. rate of climb with a simulated engine failure. (Avg is 300ft/min).Airport was practically at sea level though.

If I was departing from an airport or in conditions that cause DA to be above the aircraft's single-engine service ceiling....then I would go for the grass on the field.

And as for the advantages of having the same #value for VY or VYse?

It's easier on the brain but I believe the real intention when they publish speeds is so the pilots fly the proper attitude and angle of attack that will result in the best rate or angle of climb. The speed they publish coincidently provides the proper attitude required for that situation.

Same with Best glide speed on singles.....It's the speed that puts the wings at the best angle for LD/maX.

They try to trick you with speed values but it's really to put you at a certain pitch.

It's a dirty secret that cessna and piper did not want you to know.

 

[UndauntedFlyer]

In the seminole with two people and full tanks I've gotten 500 feet per min. rate of climb with a simulated engine failure. (Avg is 300ft/min).Airport was practically at sea level though.

Since I am sure you would not have feathered an engine for real for this test while training, you must have been using "simulated" 0-thrust. Never believe the performance results from such tests because you can never really "simulate" zero thrust. In this case unless there were probably some serious up-drafts to help performance that may have given the appearance of 500 FPM climb, it is impossible to outperform the S/E climb chart by that much just because you were maybe 400 pounds below MGW. 300 FPM climb, maybe, but not 500 FPM in the Seminole under those conditions. For accurate performance results do this test with the engine really feathered at 3000 feet AGL. The Seminole will climb about 200 FPM there, so then 300 FPM at SL would be about correct as the POH says for that weight.

 

[greyhound]

That is correct undaunted...We can never really simulate zero thrust exactly.
And we can't always get the airplane in an exact zero side-slip condition.

I did get the 500ft/min on that particular day. Used about 3 degrees bank max, ball 1/2 out. But in a real engine out situation I would not count on replicating those results.

 

[UndauntedFlyer]

That is correct undaunted...We can never really simulate zero thrust exactly.
And we can't always get the airplane in an exact zero side-slip condition.

I did get the 500ft/min on that particular day. Used about 3 degrees bank max, ball 1/2 out. But in a real engine out situation I would not count on replicating those results.

Since real 0-thrust can only be duplicated by an actual feathering of the engine, simulated 0-thrust will always give unreliable performance results. Since the results are guaranteed to be wrong, the simulated 0-thrust test is WORTHLESS. Please don't believe anything from such tests.

If you feather (real 0-thrust) at 3000 feet AGL and get 200 FPM climb, then it will be about 300 FPM at a 3000 feet lower density altitude. That's what can be figured from the POH for a PA-44.