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Fergus Kyle
Joined: 03 Jun 2007
Posts: 291
Location: Burlington ON Canada
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 Posted: Wed Jun 30, 2010 11:42 am Post subject: Speed Brakes/Spoilers |
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Dennis,
I sent this diatribe to the wrong address so here it comes now:
One of us has it right (IMHO). The spoiler cancel switch should be on the throttle. The TriStar 500 was a whiz in cockpit design. There were four different kinds of spoilers on the wing.
The first were big jobs inboard to plop the aircraft onto the tires on touchdown because you could round out, put only five of eight mainwheels on, catch a drift and touch brakes would blow out the tires on the runway – so the full weight was required to save tires – called GROUND SPOILERS. The second were roll augmenters and “speed brakes” in the air but accompanies the biggies when the touchdown was complete, the third types were outboard to balance fuel tank contents on an “active” wing (called ‘direct Lift control’ – don’t ask) and I can’t remember the 4th, but three of the four assisted in roll. The speed brakes could only be selected in air with no flap out – they were then effective brakes.
So, you can call ‘em speed brakes only if they operate to increase drag – that’s how they are engineered into the wing. Just to complicate it, there were mixers which decided if your selection was (a) acceptable and (b) possible.
The crux was on the throttles (3). The outer ones (1 & 3) had outside buttons in parallel, so were called GO AROUND buttons. If Cap’n was flying he used the No1 throttle button, if the F/O was doing it he had the No4 throttle button. When you wanted to abort the approach, you hollered “Go around”, pushed the GA button on your side as you opened the throttles to GA power. The approach was made with some spoiler panels partially extended. The button [1] demanded a proper nose-up pitch, [2] cancelled the extended spoilers instantly which allowed the aircraft to ‘leap’ upward and [3] did a number of complicated things which made aborting an approach magic and instantaneous. No other a/c could do this and it meant (very early in the trade) approaching to 7 feet (wheel height) from the runway and not drop a foot farther – without ever seeing the ground. And 90% of the exercise was aerodynamic – a miracle. Let’s hear it for partial spoilers.
I suspect the throttle is the ideal place to cancel spoilers/speed brakes because you are probably going to want to increase speed or improve lift – and now.
I have to close, I hear matron coming down the hall.
Ferg
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bbradburry(at)bellsouth.n
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| Posted: Wed Jun 30, 2010 1:28 pm Post subject: Speed Brakes/Spoilers |
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There was a major Delta crash at DFW a few years ago where the plane encountered wind shear on short final and touched down in a pasture prior to the airport. When the wheels touched, the spoilers automatically deployed and the pilot could not go around as a result. Major loss of life!
Bill B
From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Fergus Kyle
Sent: Wednesday, June 30, 2010 3:31 PM
To: 1AeroElectricLIST
Subject: Speed Brakes/Spoilers
Dennis,
I sent this diatribe to the wrong address so here it comes now:
One of us has it right (IMHO). The spoiler cancel switch should be on the throttle. The TriStar 500 was a whiz in cockpit design. There were four different kinds of spoilers on the wing.
The first were big jobs inboard to plop the aircraft onto the tires on touchdown because you could round out, put only five of eight mainwheels on, catch a drift and touch brakes would blow out the tires on the runway – so the full weight was required to save tires – called GROUND SPOILERS. The second were roll augmenters and “speed brakes” in the air but accompanies the biggies when the touchdown was complete, the third types were outboard to balance fuel tank contents on an “active” wing (called ‘direct Lift control’ – don’t ask) and I can’t remember the 4th, but three of the four assisted in roll. The speed brakes could only be selected in air with no flap out – they were then effective brakes.
So, you can call ‘em speed brakes only if they operate to increase drag – that’s how they are engineered into the wing. Just to complicate it, there were mixers which decided if your selection was (a) acceptable and (b) possible.
The crux was on the throttles (3). The outer ones (1 & 3) had outside buttons in parallel, so were called GO AROUND buttons. If Cap’n was flying he used the No1 throttle button, if the F/O was doing it he had the No4 throttle button. When you wanted to abort the approach, you hollered “Go around”, pushed the GA button on your side as you opened the throttles to GA power. The approach was made with some spoiler panels partially extended. The button [1] demanded a proper nose-up pitch, [2] cancelled the extended spoilers instantly which allowed the aircraft to ‘leap’ upward and [3] did a number of complicated things which made aborting an approach magic and instantaneous. No other a/c could do this and it meant (very early in the trade) approaching to 7 feet (wheel height) from the runway and not drop a foot farther – without ever seeing the ground. And 90% of the exercise was aerodynamic – a miracle. Let’s hear it for partial spoilers.
I suspect the throttle is the ideal place to cancel spoilers/speed brakes because you are probably going to want to increase speed or improve lift – and now.
I have to close, I hear matron coming down the hall.
Ferg | Quote: | | http://www.matronics.com/Navigator?AeroElectric-List |
0123456789
[quote][b]
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endspeed(at)yahoo.com
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| Posted: Wed Jun 30, 2010 8:33 pm Post subject: Speed Brakes/Spoilers |
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Dear Sir.
� The crash of Delta 191 at DFW on 2 Aug 85 was not caused by the spoilers deploying at touchdown. It was conjected by Monday morning qb's that had the spoilers deployed or not retracted at touchdown the aircraft would have stayed on the ground where it touched down north of Texas state route 114. Therefore, it would not have hit the water tank at DFW. �I recall that on the Tristar going to full throttle automatically retracted the spoilers. So at full throttle during the windshear encounter, the spoilers automatically retracted. Time has a way of making memories fuzzy so if anyone recollects differently please set me straight. �Incidentally, from what I can tell, EVERY airliner extends spoilers at weight on wheels during landing. To go around, advance the throttles and retract the spoilers. What might be a point of confusion is thrust reverser deployment. After thrust reverse is applied go arounds are generally forbidden by aircraft manufacturers.
Sent from my iPhone
On Jun 30, 2010, at 23:24, "Bill Bradburry" <bbradburry(at)bellsouth.net (bbradburry(at)bellsouth.net)> wrote:
[quote]
There was a major Delta crash at DFW a few years ago where the plane encountered wind shear on short final and touched down in a pasture prior to the airport. When the wheels touched, the spoilers automatically deployed and the pilot could not go around as a result. Major loss of life!
Bill B
From: owner-aeroelectric-list-server(at)matronics.com (owner-aeroelectric-list-server(at)matronics.com) [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Fergus Kyle
Sent: Wednesday, June 30, 2010 3:31 PM
To: 1AeroElectricLIST
Subject: Speed Brakes/Spoilers
Dennis,
� I sent this diatribe to the wrong address so here it comes now:
One of us has it right (IMHO). The spoiler cancel switch should be on the throttle. The TriStar 500 was a whiz in cockpit design. There were four different kinds of spoilers on the wing.
The first were big jobs inboard to plop the aircraft onto the tires on touchdown because you could round out, put only five of eight mainwheels on, catch a drift and touch brakes would blow out the tires on the runway – so the full weight was required to save tires – called GROUND SPOILERS. The second were roll augmenters and “speed brakes” in the air but accompanies the biggies when the touchdown was complete, the third types were outboard to balance fuel tank contents on an “active” wing (called ‘direct Lift control’ – don’t ask) and I can’t remember the 4th, but three of the four assisted in roll. The speed brakes could only be selected in air with no flap out – they were then effective brakes.
So, you can call ‘em speed brakes only if they operate to increase drag – that’s how they are engineered into the wing. Just to complicate it, there were mixers which decided if your selection was (a) acceptable and (b) possible.
The crux was on the throttles (3). The outer ones (1 & 3) had outside buttons in parallel, so were called GO AROUND buttons. If Cap’n was flying he used the No1 throttle button, if the F/O was doing it he had the No4 throttle button. When you wanted to abort the approach, you hollered “Go around”, pushed the GA button on your side as you opened the throttles to GA power. The approach was made with some spoiler panels partially extended. The button [1] demanded a proper nose-up pitch, [2] cancelled the extended spoilers instantly which allowed the aircraft to ‘leap’ upward and [3] did a number of complicated things which made aborting an approach magic and instantaneous. No other a/c could do this and it meant (very early in the trade) approaching to 7 feet (wheel height) from the runway and not drop a foot farther – without ever seeing the ground. And 90% of the exercise was aerodynamic – a miracle. Let’s hear it for partial spoilers.
� I suspect the throttle is the ideal place to cancel spoilers/speed brakes because you are probably going to want to increase speed or improve lift – and now.
I have to close, I hear matron coming down the hall.
Ferg 012
3
[b]
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