Meaning of “Depart”

[BillS]

I liked the little thread on the topic of “unload”. I recently met an old F-106 pilot who looked at me quizzically when I used the term “depart”. How about comments on this.

 

[ESzczesniak]

In aviation, depart would mean to “depart” from controlled flight. Generally a spin. 

[habu2]

That’s my understanding of the term as well. 

[Spruemeister]

Train up an airplane in the way that it should go, and it shall not depart from you.

 

Rick L.

[Dutch]

18 hours ago, Spruemeister said:

Train up an airplane in the way that it should go, and it shall not depart from you.

 

Rick L.

The eleventh commandment!

[GeneK]

On 3/14/2020 at 7:18 PM, ESzczesniak said:

In aviation, depart would mean to “depart” from controlled flight. Generally a spin. 

 

Yes, but there are many degrees of "departure" before getting to a full blown spin. For example, an uncontrolled violent roll opposite the intended direction of turn caused by  adverse yaw at high angles of attack ... at which point one would "unload".

 

Gene K

[Collin]

1 hour ago, GeneK said:

 

 For example, an uncontrolled violent roll opposite the intended direction of turn caused by  adverse yaw at high angles of attack ... at which point one would "unload".

 

Gene K

Unload??  You can't unload an aircraft you don't have control over, which is the essence of "departed from control flight" IMO.   

 

Been a few years, but back in my T-2C jet trainer days it (adverse yaw departures) were a ton of fun (at altitude when you are expecting it).  Neutralize controls, lock harness, SB in, trim 2-8 degrees nose up.  If positive spin confirmed, confirm throttle idle/neutral stick, rudder full opposite turn needle.  No indication passing 10K (I'll ask once if you got it)...eject (I used to jog down the beach repeating this in my head).  T-2 would depart and tumble a lot if you kept pro-spin controls in...before developing into a full (normal) spin.  Within a turn or two of the spin, with pro-recover inputs, she would always snap out of it and you would be headed nose down.  Then (AoA under control and AS rising) you are leveling your wings and starting your pull to the horizon, watching your g/AS so you don't pull back into an accelerated stall. Good times.  

 

1992: I was riding with a UK Phantom driver (in a CF-18B at the time) when he "unloaded" to get some energy back to kick the snot out of A-4 Super Fox that was giving him trouble.  Everything hit the top of the canopy....including my head since my lap belts were a little loose at the start of the engagement. He then slapped on the G to make the turn and man I was caught off guard for both the negative and positive.  Had a few red spots on my eyeballs when we landed as well.  

 

I "unloaded" once on a pilot when he got vertigo and was taking us into stall.  Sick feeling floating in your ejection seat as your watch the AS needle still moving slower....but all I cared about was getting the AoA back under 18 units (or lower) to be safe.  

 

Flying a desk sucks.

 

Cheers

Collin

 

[GeneK]

9 minutes ago, Collin said:

Unload??  You can't unload an aircraft you don't have control over, which is the essence of "departed from control flight" IMO.   

 

I won't argue semantics.  In the example I cited, you merely neutralize and ease off the stick to reduce the angle of attack, then after you've regained control, put the Gs back in and proceed.  

 

I "unloaded" once on a pilot when he got vertigo and was taking us into stall.

 

😲 Hmmm ... .

 

Gene K

[ESzczesniak]

2 hours ago, GeneK said:

 

I won't argue semantics.  In the example I cited, you merely neutralize and ease off the stick to reduce the angle of attack, then after you've regained control, put the Gs back in and proceed. 

 

Your example is a setup for spin entry.  Recovery varies by type, but often requires rudder input.  And often control input to dampen oscillations.

[GeneK]

2 hours ago, ESzczesniak said:

Your example is a setup for spin entry.  

 

HUH? Well, that's interesting ... sort of. The OP's topic is departures, not spins.  In my training/experience -- yes, incipient or full blown spins require rudder for recovery, but short of that, departures generally require neutral controls ... or forward stick (ailerons and rudder neutral). But then, as Bill Clinton once said, “It depends on what the meaning of the word ‘is’  is". I suppose the same can be said of the word 'departures'.

 

Bill, here's an excellent Navy manual that talks    Out Of Control Flight , including departures. It's for the T-45, but the aerodynamic background discussion applies to any airplane.  Page 2-8 starts good coverage of the phases which precede a spin (departures are phase two of five). 

 

Interesting topic, Bill, that can stray into many related phases of flight.

 

Gene K

[dryguy]

For anyone reading this thread and interested in this sort of thing--I highly recommend 'Greg' s airplanes' on YouTube. I thought I was knowledgeable on aerodynamics and the physics of flight-till I started watching his channel. 

[Slartibartfast]

I like Greg's.  He does great videos on Muscle cars, too.