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brian-av(at)lloyd.com
Guest

Posted: Thu Aug 24, 2006 6:44 am Post subject: Ergonomics (was: Flap switches/relay wiring)

On Aug 24, 2006, at 3:36 AM, Kevin Horton wrote:



 	  Quote: 	
		   

 <khorton01(at)rogers.com>



 What happens if there is an accidental deployment during the  

 landing flare?


	


Remember, this is a speed brake, not a spoiler. It increases drag but  

has very little effect on lift. The effect of a speed brake decreases  

as IAS decreases. The airplane slows down but not as much as at Vne.  

I doubt that speed brake would really have any significant effect in  

the landing flare.



Brian Lloyd                         361 Catterline Way

brian HYPHEN av AT lloyd DOT com    Folsom, CA 95630

+1.916.367.2131 (voice)             +1.270.912.0788 (fax)



I fly because it releases my mind from the tyranny of petty things . . .

— Antoine de Saint-Exupéry

Gilles.Thesee(at)ac-greno
Guest

Posted: Thu Aug 24, 2006 6:57 am Post subject: Ergonomics (was: Flap switches/relay wiring)

Brian and all,

 	  Quote: 	
		    I doubt that speed brake would really have any significant effect in 

 the landing flare.


	


Yes they have. Used them on a Citation to shorten the float and firmly 

plant the wheels on landing.

Now, what if the flare is a bit high and slow, or balloons, and a white 

knuckle pilot actuates the speed-brakes ? Macho contact with Mother 

Earth at best....



Best regards,

Gilles, no speed-brakes

http://contrails.free.fr

oldbob(at)BeechOwners.com
Guest

Posted: Thu Aug 24, 2006 7:08 am Post subject: Ergonomics (was: Flap switches/relay wiring)

Good Morning Matt,



This is something of a "Me Too" message. Please allow

an old man to add a bit of trivia.



We had Rolls Royce engines on the Caravelle that

needed fourteen seconds to get from idle to full

thrust. Consequently, standard operating procedure was

to use full dive brake and full flap on all

approaches. That allowed about sixty-five to seventy

percent power to be carried on the approach. In the

event of a go around, we retracted the speed brakes

and took the flaps to departure setting immediately. 

As you stated earlier, the speed brakes didn't provide

an awful lot of drag at those low speeds, but every

little bit did help. By maintaining the approach speed

as high as the departure speed, we could rotate the

aircraft as the flaps were retracted and avoid any

loss of lift from the flap retraction. (Works just as

well in a Cessna 152 as it does in the Caravelle). As

soon as a positive rate of climb was attained, the

landing gear would be retracted.



As another minor point, during the acceptance tests

for the Caravelle, one of our pilots asked how the

aircraft would perform if the speed brakes failed to

retract. The French test pilot extended the speed

brakes, took off and made a complete circuit around

the field without ever retracting them!



As to glider operation with speed brakes, we once

owned a Schweitzer 2-32. As you probably already know,

it has monstrous terminal velocity limiting dive

brakes. With the brakes extended, it is impossible to

get the speed above the redline.



As a hot rod show off maneuver, we would use full dive

brake and make an approach to a twenty five hundred

foot runway holding about one hundred MPH. Over the

threshold, we could either leave the speed brakes out

and land comfortably in the landing length available

or retract the speed brakes and make another circuit

of the field for a normal landing.



Drag that you can get rid of is just another source of

available power!



Happy Skies,



Old Bob



Do Not Archive



--- Matt Prather <mprather(at)spro.net> wrote:



 	  Quote: 	
		   

 Prather" <mprather(at)spro.net>

 

 Mr. Thesee,

 

 I just posted another message.  Yours reminds me

 that I didn't mention a

 few things...

 

 Early (modern?) fighter jets often flew their final

 approach with speed

 brakes at least partially extended.  This allowed

 them to carry nearly

 full power on the engine while on approach.  If they

 had to abort an

 approach, the speed brakes could be stowed much more

 quickly than climb

 power could be attained from the jet.  The speed

 brakes were relatively

 large, and not designed to be deployed at high

 airspeeds.

 

 Gliders often have truly enormous speed

 brakes/spoilers which allow steep

 approaches to be flown - drastically reducing their

 glide ratio.  All of

 the ones I have seen are mechanically actuated by a

 large lever in the

 cockpit.

 

 The speed brakes that I was thinking of are like the

 Precise Flight units

 commonly installed on higher performance piston

 singles like Mooney's,

 Lancairs, Glassairs, Bonanzas and Cessna 210's. 

 These are electrically

 actuated.  Mounting the control switch either

 near/on the throttle or on

 the control wheel/stick might make the most sense. 

 These units are

 approved for airspeeds up to Vne.

 

 http://preciseflight.com/viewpage.php?pID=10

 

 

 Regards,

 

 Matt-

 

 

 > 

 Thesee

 > <Gilles.Thesee(at)ac-grenoble.fr>

 >

 > Bill Denton a écrit :

 >> 

 Denton"

 >> <bdenton(at)bdenton.com>

 >>

 >> I was thinking more in terms of the other end of

 the spectrum...

 >>

 >> What would happen if the speed brakes were

 accidentally deployed on

 >> short

 >> final?

 >>

 >>

 >

 > The end result would be "interesting" 

 >

 > Fighters have speed brakes on the throttle,

 because they need it for

 > formation flying, in-flight refuelling, etc. Their

 jet engines do not

 > allow for quick speed reduction.

 > On other types, airliners or gliders, the speed

 brakes do have a

 > dedicated and (hopefully) unmistakeable lever.

 >

 > On a piston single, unless the owner is a

 nostalgic ex-fighter pilot, is

 > a throttle switch really desirable ? Piston

 engines and props allow for

 > quick speed reduction for formation flying, for

 instance.

 > Any time you add a switch on the stick or

 throttle, provision must be

 > made to avoid inadvertent actuation.

 >

 > I know of at least one clever guy who installed

 the starter switch on

 > the throttle...

 >

 > Regards,

 > Gilles Thesee

 > Grenoble, France

 > http://contrails.free.fr

 >

 >

 >

 >

 >

 >

 >

 

 

 



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 Subscriptions page,

 FAQ,

 http://www.matronics.com/Navigator?AeroElectric-List



 Web Forums!

 Admin.

khorton01(at)rogers.com
Guest

Posted: Thu Aug 24, 2006 1:14 pm Post subject: Ergonomics (was: Flap switches/relay wiring)

On 24 Aug 2006, at 10:43, Brian Lloyd wrote:

 	  Quote: 	

 av(at)lloyd.com>

 On Aug 24, 2006, at 3:36 AM, Kevin Horton wrote:

> 

> <khorton01(at)rogers.com>

>

> What happens if there is an accidental deployment during the  

> landing flare?

 Remember, this is a speed brake, not a spoiler. It increases drag  

 but has very little effect on lift. The effect of a speed brake  

 decreases as IAS decreases. The airplane slows down but not as much  

 as at Vne. I doubt that speed brake would really have any  

 significant effect in the landing flare.

Sorry, I thought that the Glasair installation was likely on the  

wing, and its deployment would reduce the lift, as well as produce  

extra drag.  I was wondering if the loss of lift at low speed at a  

critical flight phase could be a problem.

Air Canada had a fatal accident with a DC-8 at Toronto many, many  

years ago.  There was a screw up in the flight deck, which resulted  

in the ground spoilers being deployed at about 60 ft AGL.  No survivors.

http://aviation-safety.net/database/record.php?id=19700705-0

If the Glasair speedbrakes are not on the wing, then my original  

question was not relevant.

Kevin Horton         RV-8 (finishing kit)

Ottawa, Canada

http://www.kilohotel.com/rv8

brian-av(at)lloyd.com
Guest

Posted: Thu Aug 24, 2006 1:55 pm Post subject: Ergonomics (was: Flap switches/relay wiring)

Kevin Horton wrote:

 	  Quote: 	
		  > Remember, this is a speed brake, not a spoiler. It increases drag but 

> has very little effect on lift. The effect of a speed brake decreases 

> as IAS decreases. The airplane slows down but not as much as at Vne. I 

> doubt that speed brake would really have any significant effect in the 

> landing flare.

 Sorry, I thought that the Glasair installation was likely on the wing, 

 and its deployment would reduce the lift, as well as produce extra 

 drag.  I was wondering if the loss of lift at low speed at a critical 

 flight phase could be a problem.

Probably not as the speed brake tends to be well aft of the point of 

maximum thickness and very little of the span. It has very little impact 

on lift.

 	  Quote: 	
		   Air Canada had a fatal accident with a DC-8 at Toronto many, many years 

 ago.  There was a screw up in the flight deck, which resulted in the 

 ground spoilers being deployed at about 60 ft AGL.  No survivors.

Yeah, well, the ground spoilers are supposed to kill ALL lift. That is a 

completely different story.

 	  Quote: 	

 http://aviation-safety.net/database/record.php?id=19700705-0

 If the Glasair speedbrakes are not on the wing, then my original 

 question was not relevant.

And even if they are, I think you will find they have very little effect 

if deployed while in landing configuration.

Regardless, don't take my word for it. Be sure to try it yourself.

Brian

oldbob(at)BeechOwners.com
Guest

Posted: Thu Aug 24, 2006 2:06 pm Post subject: Ergonomics (was: Flap switches/relay wiring)

Good Afternoon Kevin,



This may have little or no bearing on the subject at

hand, but the DC-8 had no speed brake at all!



They originally designed one that came out of the

fuselage at the wing root. It was totally ineffective

and the design was too far along to incorporate a

speed brake in the wing structure. They fixed it by

making the engine reversers usable in flight. If you

wanted a speed brake function in the DC-8, you used

inflight thrust reversing.



They did employ ground spoilers which were designed to

kill as much lift as possible. They were located along

the trailing portion of the primary wing structure.

Speed brakes that are intended to provide inflight

drag tend to be mounted further forward on the wing

and be designed so they destroy very little of the

lift being developed by the wing. Obviously, there are

many variations. Boeing tends to use sections of the

trailing edge that also serve as ground spoilers The

Caravelle a had a beautiful set of brakes that looked

like big brothers of those used on gliders.



In general, the inflight speed brakes have a

relatively small effect on the lift being produced.

The ground spoilers are designed to kill as much of

the lift as is possible.



No doubt many of our listers can point to exceptions

where the functions are mixed even more so than on the

Boeings, but the DC-8 had NO speed brakes at all

within the aircraft structure. Just the inflight

reversing capability. That actually worked quite well.

but it sure made a lot of noise and a lot of

vibration!



Happy Skies,



Old (Once upon a time DC-8 captain) Bob



--- Kevin Horton <khorton01(at)rogers.com> wrote:



 	  Quote: 	
		   

 Horton <khorton01(at)rogers.com>

 

 On 24 Aug 2006, at 10:43, Brian Lloyd wrote:

 

 > 

 Lloyd <brian- 

 > av(at)lloyd.com>

 >

 >

 > On Aug 24, 2006, at 3:36 AM, Kevin Horton wrote:

 >

 >> 

 Horton  

 >> <khorton01(at)rogers.com>

 >>

 >> What happens if there is an accidental deployment

 during the  

 >> landing flare?

 >

 > Remember, this is a speed brake, not a spoiler. It

 increases drag  

 > but has very little effect on lift. The effect of

 a speed brake  

 > decreases as IAS decreases. The airplane slows

 down but not as much  

 > as at Vne. I doubt that speed brake would really

 have any  

 > significant effect in the landing flare.

 

 Sorry, I thought that the Glasair installation was

 likely on the  

 wing, and its deployment would reduce the lift, as

 well as produce  

 extra drag.  I was wondering if the loss of lift at

 low speed at a  

 critical flight phase could be a problem.

 

 Air Canada had a fatal accident with a DC-8 at

 Toronto many, many  

 years ago.  There was a screw up in the flight deck,

 which resulted  

 in the ground spoilers being deployed at about 60 ft

 AGL.  No survivors.

 



http://aviation-safety.net/database/record.php?id=19700705-0
	


 	  Quote: 	
		   

 If the Glasair speedbrakes are not on the wing, then

 my original  

 question was not relevant.

 

 Kevin Horton         RV-8 (finishing kit)

 Ottawa, Canada

 http://www.kilohotel.com/rv8

 

 



 browse

 Subscriptions page,

 FAQ,

 http://www.matronics.com/Navigator?AeroElectric-List



 Web Forums!

 Admin.

Gilles.Thesee(at)ac-greno
Guest

Posted: Thu Aug 24, 2006 2:16 pm Post subject: Ergonomics (was: Flap switches/relay wiring)

 	  Quote: 	
		   In general, the inflight speed brakes have a

 relatively small effect on the lift being produced.

 The ground spoilers are designed to kill as much of

 the lift as is possible.

   

When on the wings, "drag only" speed-brakes tend to look like fences 
	


lifted at a distance from the wing skin, in order to preserve the 

airflow on the wing upper surface.

If they block part of the airflow on the wing, then they'll kill lift as 

well as increase drag.



Regards,

Gilles

http://contrails.free.fr

ogoodwin(at)comcast.net
Guest

Posted: Thu Aug 24, 2006 3:32 pm Post subject: Ergonomics (was: Flap switches/relay wiring)

Right you are about the DC8, Bob.  I too flew it (about 12 years straight). 

It always seemed an unnatural act to deliberately use reverse in flight....



An exception to what you say about speed brakes not having much effect on 

lift is the Boeing 727, an all around wonderfully capable airplane.  The 

speed brakes (flight spoilers) were so effective you could actually lose 

10,000 feet in less than 10 miles or slow from 350 IAS to 250 in about 4 

miles,  not something you'd want to do in a pax airplane (the descent 

anyway), but lots of fun with boxes.  Two fine airplanes, either of which I 

wish I was still flying.



Olen Goodwin

---

luckymacy(at)comcast.net
Guest

Posted: Thu Aug 24, 2006 4:38 pm Post subject: Ergonomics (was: Flap switches/relay wiring)

OK. Off topic but the 727 seems like THE plane to FLY.  I know a retired 747 pilot who said the most fun he ever had, the best plane and routes he ever had were with 727s.  You got to go to a lot of places not serviced by the larger planes including some class d airports and the plane itself was fun/sporty to fly. Lots of "interesting" central, south american spots too. But of course the retirement is based on final salary years so you "have to" move up to 747s if you can work it out...

  

 [quote]-------------- Original message -------------- 

From: "Olen Goodwin" <ogoodwin(at)comcast.net> 



[quote] --> AeroElectric-List message posted by: "Olen Goodwin" 

 

 Right you are about the DC8, Bob. I too flew it (about 12 years straight). 

 It always seemed an unnatural act to deliberately use reverse in flight.... 

 

 An exception to what you say about speed brakes not having much effect on 

 lift is the Boeing 727, an all around wonderfully capable airplane. The 

 speed brakes (flight spoilers) were so effective you could actually lose 

 10,000 feet in less than 10 miles or slow from 350 IAS to 250 in about 4 

 miles, not something you'd want to do in a pax airplane (the descent 

 anyway), but lots of fun with boxes. Two fine airplanes, either of which I 

 wish I was still flyi  ng. [b]> 

 Olen Goodwin 

 ---

ogoodwin(at)comcast.net
Guest

Posted: Thu Aug 24, 2006 7:24 pm Post subject: Ergonomics (was: Flap switches/relay wiring)

Too bad the old airplanes that required "piloting"  are all being retired.  I enjoyed them, and I think lots of the guys that  liked flying for it's own sake did.  Interesting what you said about the  747...that's where I'm headed in October.  Bittersweet indeed.

  

 Apologies for the off topic.

  

 Olen 

 [quote]   ---

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