What is V-end?

[William Pete Hodges]

What is V-end?

I have a book that I refer to occasionally called "Flying The Edge, Flight at the Threshold of Optimum Performance" by Capt. Brian McAllister. The book is very good, but for me, most of the meat in this book is in chapters 4, 5 and 6, where he discusses STOL operations, STOL takeoffs and STOL landings.

In chapter 4 on page 104 he refers to figure 4.11 "Power Available within Slow Flight Limits" which is a gaph showing power available vs power required. The bottom of the Power Required curve is referred to as V-end. It is not otherwise defined in the book and I am curious as to what it is.

 

[Let'sgoflying!]

endurance

 

[Salty]

would be the same as best L/D, no?

 

[Hang 4]

No Y-axis label, so just guessing. Left of the line is "behind the power curve"?

 

[RussR]

Since it's at the point of minimum power required, I would assume that he means "max endurance speed".

But that's why terms should always be defined!

 

[Lachlan]

This is V end. My only friend, V end.

-Jim Morrison, Certified Trip Instructor, Ground

 

[MauleSkinner]

would be the same as best L/D, no?

Best L/D should be where a line from the origin is tangent to the curve.

 

[charheep]

This is V end. My only friend, V end.

-Jim Morrison, Certified Trip Instructor, Ground

Bravo. Very well done!

 

[Clip4]

V-end - the speed where reducing the throttle to fly slower has ended (Vbe -best endurance speed).

 

[dmspilot]

would be the same as best L/D, no?

If that was a thrust required curve L/D max would be the low point in the graph, since thrust=drag and lift=weight in steady state flight. But as Maule pointed out, on a power curve L/D max is tangent to the curve.

 

[Piperonca]

What is V-end?

Might be this:

 

[sarangan]

I assume the vertical axis is power since the two curves are labeled as "power required" and "power available". The lowest power required would correspond to lowest fuel consumption, hence the maximum endurance.
There is another type of plot where the vertical axis is force. Force is power divided by speed, so this plot is really the gradient of the first plot. The two separate lines will be "thrust required (which is the same as drag)" and "thrust available". Force multiplied by distance is energy. For a given energy, if you minimize force, you will maximize distance. The energy is potential energy due to your altitude. You can convert a given altitude into maximum distance by flying at the speed that gives the lowest drag, or highest L/D. This is the best glide range speed.

 

[charheep]

OK, what is V-ger?

 

[MauleSkinner]

OK, what is V-ger?

Voyager, with some lettering burned off.

 

[bflynn]

OK, what is V-ger?

The plot twist of a bad Star Trek movie.

 

[iamtheari]

The plot twist of a bad Star Trek movie.

Hey, spoiler alert!

 

[Crashnburn]

Hey, spoiler alert!

We should all know that the odd # Star Trek movies pale in comparison to the even number movies.

 

[Scott Mitchell]

Best I could find.
A rose by any other name I guess

 

[Piperonca]

What is V-end?

Here's another take on it: https://www.aviationsafetymagazine.com/features/less-power-for-more-aircraft-range/?amp=1

What McAllister calls Area of Slow Flight is also called Region of reversed command. Who knew? That's the one on the left side of the vending machine where Dante's 'abandon all hope ye who enter here' is in effect. That means you're in deep brown stuff. See also James Taylor, 'sweet dreams and flying machines and pieces on the ground.'

 

[Rich Holt]

MaxE vs MaxR. How long can I stay aloft vs how far can I go.

 

[Piperonca]

MaxE vs MaxR. How long can I stay aloft vs how far can I go.

Good concise definition. But be mindful both speeds are a function of gross weight. Also MaxR will vary with headwind/tailwind. Rules of thumb are helpful, or let Foreflight find the best speed for you. Effect may be small, but sometimes very important.

 

[William Pete Hodges]

Thanks to all of you for your replies. I am glad I asked.