B-717 thing on nosegear

[AA717driver]

Huh, I always thought those thingies were foot rests for cleaning the windshield. You know, grab one of those pointy things sticking out on the nose and swing yourself up till you can get your foot on the foot rest... er, excuse me, strakes.

Boy, you learn something new every day. TC

P.S.--I was wrong about the doofus who ran out and stopped the AA S80. He was civilian. There, is that better?

 

[Jeff Helgeson]

Touch the stall vain on th epre-flight next time...

Huh, I always thought those thingies were foot rests for cleaning the windshield. You know, grab one of those pointy things sticking out on the nose and swing yourself up till you can get your foot on the foot rest... er, excuse me, strakes.

Boy, you learn something new every day. TC

P.S.--I was wrong about the doofus who ran out and stopped the AA S80. He was civilian. There, is that better?

touch the stall vains next time near the strakes on the walk-around to see if they move freely.

Sssss, smells like bacon! Not that it ever happened to me.

 

[Jeff Helgeson]

I didn't open a book either...

It would be closed book because my MD-80 and DC-9 manuals are all in storage in my favorite city ( Charlotte, NC ) .

Excuse the time delay, I was out for awhile. This is a WAG since I haven't seriously studied the systems for 6 years, I'll go with ( C ).

TP

...but C would be correct.

 

[typhoonpilot]

Something told me to go with my instinct on the answer or it was just a lucky guess.

TP

 

[flx757]

Not so fast....

On the MD-80, the strakes are heated in conjunction with the wings.

The fail-safe, unpowered position of the wing and tail de-ice valves are:
Wing and strake--open
Tail -- closed
Therefore, when first turning the system on, (opening the anti-ice pressure regulating and shutoff valve), 13th stage air is supplied to the wings and strakes.

The tail de-ice valve then opens when the wing and strake valve closes either:
automatically, every 15 mins
for 2.5 mins whenever you push the "tail de-ice" button
or for 2.5 mins after selecting airfoil anti-ice off.

The Ram Air Scoop at the base of the vertical stab is the only component pneumatically heated (with 13th stage air) regardless of wing/strake or tail de-ice valve position, i.e anytime the airfoil anti-ice system is on.

So, the correct answer is (a).

(At least this is the way it works on all MD-80s operated by Alaska Airlines. )

 

[Jeff Helgeson]

I should have looked at the book.....

Not so fast....

On the MD-80, the strakes are heated in conjunction with the wings.

The fail-safe, unpowered position of the wing and tail de-ice valves are:
Wing and strake--open
Tail -- closed
Therefore, when first turning the system on, (opening the anti-ice pressure regulating and shutoff valve), 13th stage air is supplied to the wings and strakes.

The tail de-ice valve then opens when the wing and strake valve closes either:
automatically, every 15 mins
for 2.5 mins whenever you push the "tail de-ice" button
or for 2.5 mins after selecting airfoil anti-ice off.

The Ram Air Scoop at the base of the vertical stab is the only component pneumatically heated (with 13th stage air) regardless of wing/strake or tail de-ice valve position, i.e anytime the airfoil anti-ice system is on.

So, the correct answer is (a).

(At least this is the way it works on all MD-80s operated by Alaska Airlines. )

You are absolutely correct. I meant to say Ram Air Scoop. So I was wrong. For the record, I can find my A$$ with both hands if I have the proper aeronautical charts. In this case, the proper systems manual. All this, I think I just missed Scooby Doo. Well, there's always tomorrow!


Good Show!

 

[flx757]

Well, I admit I had somewhat of an advantage. I'm sitting here at my desk surrounded by all the manuals. Plus, Ice Protection was one of this year's (well...I guess it is LAST year's now...) subjects in recurrent.

(Wish I were watching Scooby Doo instead of sitting here with nothing to do... )

 

[Jeff Helgeson]

Your Kung Fu is superior today....

Well, I admit I had somewhat of an advantage. I'm sitting here at my desk surrounded by all the manuals. Plus, Ice Protection was one of this year's (well...I guess it is LAST year's now...) subjects in recurrent.

(Wish I were watching Scooby Doo instead of sitting here with nothing to do... )

...but I'll be back to fight another day!

 

[FN FAL]

The MD80's has it too. In the late '80's at a commuter we had this doofus ex-Air Force guy (every service/company has a few) who ran out on the ramp/taxiway at BUR to flag a AA MD80 that was taxiing out. He thought it was dragging the chocks behind the nosewheel...

That REALLY impressed the AA people.TC

I suppose this airforce guy would have run out in front of me when I was tooling around my 1964 320 Skyknight, it had new fangled FENDER technology on the front wheel as well. Imagine that?

I still find it hard to believe that fender technology took 40 years to uptrickle into jet airliners. I bet the Model T Ford had fenders on the wheels to keep mud from splashing all over everything too, but those only came in one color.

 

[FN FAL]

According to Freddy Fenders, splash guards now come in assorted colors...

http://www.planetbike.com/fenders.html#

 

[Swede]

At least once a month, it seems, someone will panic on the radio when they see the MD80's "split" elevators flopping about on the ground as wind gusts hit them. "OMG, the torque tube between the elevators on that jet has failed!!"

 

[bafanguy]

Good memory. More exactly, they reduce the fuselage vortex that can occur at high AOA. That vortex would impinge on one side of the vertical stabilizer and rudder thus decreasing directional control.

They were first introduced with the stretched DC-9-50 and appear on the MD-80 and MD-90 as well. They do not appear on the DC-9-30, B717, or other shorter versions as the fuselage vortex is not an issue.

TP

TP is right. Before they figured out I was a nobody and cut off my subscription, DC Flight Approach magazine published a good article about the strakes on -80 series. Can't find my original copy so I can't give a date for the issue, but from the copy I had stuffed in my systems manual, the first paragraph says:

"Fuselage strakes have been included in the DC-9-50 and MD80 family of aircraft to improve directional stability of these long-nosed Douglas aircraft when flying in a sideslip at high angles of attack. Nacelle strakes were added to the MD80 to provide additional recovery capability in the event of a deep stall."

" ... strakes generate vortexes that alter the local flow past the vertical tail, providing good directional stability over the greatest range of angles of attack, sideslip, and flap deflection."

Apparently, on the shorter series, the problem was avoided by the rudder limiter ( flap/rudder limiter) alone.

 

[Freddie Spencer]

you are all wrong... it's just a place where airtran pilots can put the six pack while they do the walk around.

 

[walden]

Mr. Spencer has the idea, I believe, that he is funny. He is not. But considering his feeble attempts at self-validation it may be the best course to simply snicker and move on. A person that hangs his ego on the degradation of others has issues.

 

[AA717driver]

walden--LTFU! Freddie's post was intended as humor, not degradation. His avatar is degrading. (Not that there's anything wrong with that!) TC

 

[walden]

AA717,
Whatever 'LTFU' means...I'm sure its a term of endearment.
I just noticed quite a bit of his "intended humor" centered around the same thing; someone else's shortcomings or misfortune. As you say, "not that there's anything wrong with that."
Pax,
walden