What's wrong with this picture?

[jesse]

Could you post a little more detail about the VL factor? You've obviously piqued a lot of people's interest.

Chris

Sure-- I made it up. I was waiting to see if people would call me on it or claim they knew about it.

The comment I made towards you was also a joke--me not knowing crap about aerodynamics challenging an aerospace engineer (that is what you do isn't it?).

Those that know me--probably could tell I was just making crap up. Those that don't--it won't kill them to think I'm a jerk for a day or two.

 

[Frank Browne]

Those that don't--it won't kill them to think I'm a jerk for a day or two.

Well...I'm still breathing.

Seriously, I did think you were being serious, and I did think you were being a jerk. But now that I know that you enjoy pulling peoples chains, I'll be on the lookout from now on.

 

[cwyckham]

Damn, you got me hook line and sinker. I admit that I thought for a second that you were making things up, but then that jerk Tony got in on the act and convinced me otherwise.

I at least know you well enough to know that in your last couple posts you were intentionally trying to seem like a jerk, but I thought you were just enjoying the glory of knowing something the rest of us don't.

Chris

 

[gprellwitz]

Hey, I DO know you, and was starting to get a little pi$$ed! Heck, I was even thinking of threatening to withhold a certain manual that I'm now heading out to mail!

 

[Don Jones]

Hey, I DO know you, and was starting to get a little pi$$ed! Heck, I was even thinking of threatening to withhold a certain manual that I'm now heading out to mail!

Joke is on Jesse, it really is a term from aircraft design. Here is an excerpt from an advisory circular I found. Look at the date on it though.

Sec. 14. Design Speeds

(A) The two basic design speeds are designated VL and Vg. VL denotes the high speed of the airplane in level flight, reduced to the equivalent “indicated” air speed at sea level in standard air, as defined in section 11 (H). (See also Aeronautics Bulletin No. 26, sec. 6.) Vg represents the design gliding speed used in the analysis of the structure and is also considered to be “indicated” air speed, as in the case of VL.

(B) The high speed, VL, should be estimated as accurately as possible or determined from flight tests. The design high speed used in the stress analysis shall not be less than the high speed of the airplane finally determined from flight tests and reduced to the equivalent “indicated” air speed as defined in section 11 (H).

(C) The minimum design gliding speed shall be determined from the following equation:

Vg = VL + Kg (Vm - VL) (need not exceed VL + 150 ft./sec.)

Where VL = design high speed. (See par. B of this section.)

Vm = maximum theoretical vertical speed in standard air with zero propeller thrust.

 

[Henning]

About 37% higher than the VL-factor is about the lower end of the critical threshold. 48% and it's good night.

WTF are you talking about?!?

 

[KennyFlys]

The POH W&B is all about the longitudinal axis. I think you meant to say lateral axis? (longitudinal= fore/aft - lateral= side/side)

An airplane's balance pivots on the lateral axis. Balance is measured along the longitudinal axis. I had to stop and make sure I used the right axis when I first wrote that.

 

[cwyckham]

The POH W&B is all about the longitudinal axis. I think you ment to say lateral axis? (longitudinal= fore/aft - lateral= side/side)

This is one of the really annoying things about the whole longitudinal/lateral terminology. When I say longitudinal stability, I mean stability in the fore/aft direction. Kenny says "on the longitudinal axis" which implies the same thing, since the longitudinal axis runs fore and aft through the center of the fuselage. What I think Kenny meant to say is "about the longitudinal axis" which would mean rotations about the fore/aft axis (roll or lateral stability).

 

[Henning]

An airplane's balance pivots on the lateral axis. Balance is measured along the longitudinal axis. I had to stop and make sure I used the right axis when I first wrote that.

Yeah, sorry, I had already deleted. My brain isn't working quite right and I was thinking "along" rather than "around". My bad.

 

[cwyckham]

Yeah, sorry, I had already deleted. My brain isn't working quite right and I was thinking "along" rather than "around". My bad.

Not your bad at all. "On" is imprecise. I would also interpret it as "along" instead of "about" or "around." We're all just getting tied up in the terminology.

 

[KennyFlys]

Yeah, sorry, I had already deleted. My brain isn't working quite right and I was thinking "along" rather than "around". My bad.

Tis ok. Like the guy from "the other land down under" said, it's easy to confuse them. You say "about", I say "along."

As for the document Don dug up... I'll read that after I get my degree in aerospace engineering. That would be quite a stretch from an accounting guy now running drugs for a living! By the way, did I say, "I hate math!"?

 

[Dave Siciliano]

I thought that was a 'runway feeler'. You know, kinna like curb feelers on a car. It's really difficult to see the runway when one flares, listen for the scraping sounds and round out!

What, that's not what it is <vbg>

Best,

Dave

 

[Don Jones]

I thought that was a 'runway feeler'. You know, kinna like curb feelers on a car. It's really difficult to see the runway when one flares, listen for the scraping sounds and round out!

What, that's not what it is <vbg>

Best,

Dave

LOL, now that right there is funny, don't care who you are!!!

 

[KennyFlys]

LOL, now that right there is funny, don't care who you are!!!

Larry... I agree!

 

[SCCutler]

I thought that was a 'runway feeler'. You know, kinna like curb feelers on a car. It's really difficult to see the runway when one flares, listen for the scraping sounds and round out!

What, that's not what it is <vbg>

Best,

Dave

Dave, I thought "runway feeler" was what that B55 pilot used at ADS a few weeks back... in fact, he had two of 'em, three blades each. He "felt" it, alright... then he felt kinda puny.

 

[tonycondon]

Damn, you got me hook line and sinker. I admit that I thought for a second that you were making things up, but then that jerk Tony got in on the act and convinced me otherwise.

sorry...

Jesse said "say something that makes it sound official" and i couldnt help but bite.

 

[Dave Krall CFII]

The VL numbers are real, and very heavy.
You get to thinking about too many of those and the plane can't fly with all the weight.

 

[Dave Siciliano]

Dave, I thought "runway feeler" was what that B55 pilot used at ADS a few weeks back... in fact, he had two of 'em, three blades each. He "felt" it, alright... then he felt kinda puny.

Never heard those called "runway feelers" before Spike. The term I always heard was Aw S**T! Of course, that is a less precise term used for more than this malady.

Aw S**t is usually followed by a prompt query from the person in the right seat as their eyes enlargen and and body stiffens--somethings like: whatdaF**k'dyado!?

The left seater then finds religion and uses the name of our Lord's son in vain. Jeeess etc.

Sometimes this excited utterance is while the plane is sliding down the runway making sounds like someone scratching their finger nails on a chalk board for a prolonged period of time.

As the plane comes to a stop, various last minute measures are taken to prevent fire and the discovery of how dumb the maneuver was:
Mixture Out;
Master--Off;
Fuel Selector--Off;
Mags.-- Off;
Gear Selector--Down.

Best,

Dave

 

[KennyFlys]

"Gear Selector--Down"? Yes, I suppose putting the gear down at some point is a good idea. Hey, at least it's on the list... somewhere!

 

[Dave Siciliano]

Ken:
The cases are very well documents; pilot puts the gear down switch in the gear down position after a gear up landing!!
Prepares for the interview with his insurance agent--sure I put the gear down. Must have been a mechanical failure! Go ahead and look--see itsdown!!

Best,

Dave