Spoiler arm auto-deployment

[vidarf]

Hi gents!

I've been playing around with my LEGO Mindstorm-set (don't act like you don't envy me!). I've been thinking about the spoiler arm deployment / retraction. On the 737, the spoilers are automatically deployed upon ground contact or in the event of a RTO. Should a go-around be initiated after landing and the spoilers are up, they will automatically be retracted. This is something I want to add to my TQ.
So here's the idea:
http://www.mycockpit.org/photopost/showphoto.php?photo=3899

In short, this solution will automatically raise the spoiler arm from the down detent, and then depoy the spoilers. The secret is a bell-cranck, which is a L-shaped contrapment that transfers horizontal movement into vertical movement (other uses are possible too).

The important thing to achieve here, is that there should be a bit of "play" in the linkage from the servo / motor to the spoiler arm to remove the load of movement.

Any comments, suggestions and improvements are VERY welcome! :)

[dnoize]

Nice build....we all love LEGO mindstorm....well, i do....

but:

Spoilers only auto deploy after they have been armed (armed detend). That means you allready raised and armed the lever manuallyin case of autobreak.
No auto raise from the down detend for the speed brake lever.

Stef



.

[vidarf]

Are you sure? Doesn't the spoilers deploy if a RTO occurs?

[Trevor Hale]

On the Airbus, the Spoilers are armed before take off for an RTO situation,

But in the Boeing.. I have never seen arming the spoilers as part of the pre-takeoff checklist.

Trev

[vidarf]

That's my experience also - not in any of my DVD's or in the two jumpseat-rides I got. I don't know if the spoilers deploy during a RTO, or if the pilots have to do it manually.

[dnoize]

From the Quick Reference Handbook that KLM uses:



Before start:

* AUTOBRAKE........................RTO
* SPEED BRAKE........DOWN DETENT

from Bill Bulfers book:



AUTO BRAKE SELECT SWITCH
-used to select te RTO or the desired deceleration rate of auto braking after landing
-landing mode selection equals total deceleration (thrust reverse plus braking)


also, when armed, flight spoilers come up at wheel spinup on any 2 main wheels.
ground spoilers come up when mechanical squat switch on right gear is compressed.




Stef




.

[ivar hestnes]

I took some shots from my QRH to enlighten this. On a RTO takeoff, the speedbrakes is raised manually:).

http://i31.photobucket.com/albums/c380/vrinsk/009-3.jpg

http://i31.photobucket.com/albums/c380/vrinsk/018-2.jpg

http://i31.photobucket.com/albums/c380/vrinsk/023-1.jpg

http://i31.photobucket.com/albums/c380/vrinsk/022-2.jpg

[dnoize]

Are you sure? Doesn't the spoilers deploy if a RTO occurs?

nope...

has to be done manually.....

see my posts for before take off....

and ivars post for the RTO


Stef

[vidarf]

Great, thanks guys! :) This made the whole idea of mine MUCH more simple! :) Now I can skip the whole contrapment and use a simple switch to cut power to the motor if the spoiler arm isn't raised and armed.

This right here is the great thing about forums like this: You ALLWAYS find an answer!

Ivar, if you have one of those QRH laying around as a leftover... :D

[ivar hestnes]

haha, you wish :mrgreen:

I actually had one more set, but Svein got that one. Sure he wont sell it;)

[vidarf]

Thanks a lot, you ¤%&/(&%¤&%/!!!! Forbanna molde-gauk! :D

[Michael Carter]

You do and you'll clean it up! :p

[Lambis777]

Sorry that i say this but the speedbrake lever jumps out from the down detent when the pilot forget the lever to the down position and WHEN deploy the reverse levers.



This happen only in the case that the lever is still in the down position when the aircraft is landing. (pilot mistake).

For the normal operation the pilot manualy place the lever to the arm position.

I ask and 737 and 777 pilots for this.

Lambis
Greece

[ivar hestnes]

Dont be sorry to post this buddy:)

Seems that there is always new stuff to learn. This subject is not so good described in the manuals. I got the same info from a reliable source aswell so sure you are right.

Description from my source below:

All 737NG takeoff's are done with the Speedbrake lever in the "DOWN"
position. The detent in the "DOWN" position prevents accidental deployment of the Spoilers during takeoff. If the one of the thrust levers is moved to "Reverse" then the mechanical linkage pushes up the Speedbrake lever, (so the tab clears the detent) and the auto speedbrake actuator moves the Speedbrake lever to the up position.

If the aircraft has not reached the wheel spinup speed and one of the thrust levers is moved to "Reverse" then the mechanical linkage pushes up the Speedbrake lever, BUT the pilot must move the Speedbrake lever to the up position.

Thanks for posting Lambis:)

[Lambis777]

Somewhere in my hard drive i have a scetch from the maintanence manual that show this device that jump out the lever from the down position.

it will be very userfull for those who want to make the speedbrake lever as the real speedbrake lever.

tommorow i will try to search this file.
Give me some time

Lambis
Greece

[vidarf]

THIS IS AWESOME! :) Thank you SO MUCH, folks! This will increase the level of realism. Sadly, it will also increase the workload. Oh, well.... :)

Don't you just love this hobby and its level of complexity? Allways something to bend your brain around!

[Lambis777]

Hi Again

I attach the scetch that show the mechanism that push out the lever from the down detend.

Lambis
Greece

[dnoize]

what aircraft is that from ? (levers dont look like 737).

I have checked with my real 200 throttle and it has no provision whatsoever to lift the lever. But ofcourse its from a 200 so everything can be different.

I've just checked maintanance manuals of a 300/400/500 and i cant find any reference there.

Next thursday i will be in a NG flightdeck. Will check with the pilot.

There are so many versions. Until recently i had never heard of a NG without autothrottle either, but i just recently found out that those exist too ! i had never heard of it before...

Thanks for the drawing lambis. We learn every day new things in this hobby :-)

Stef

[Lambis777]

I think are from 767. I seen familiar mechanism and for 777.
The pilot 737 that i ask flys NG but i don`t ask him if all the models or the old models have this mechanism.

Stef your visit next week in the NG flightdeck they will give us the answer.

I hope you guys understand my bad English.

Lambis
Greece

[dnoize]

Just checked one of my other manuals and scanned this page.

Check the third paragraph on the right.

Spoilers do extend automatically after rejected take off, when reverse levers are pulled.
Since the "before take off" orders the pilots to have the speedbrake lever in the down detend i have to assume the lever rises automaticallym.

Will check next thursday and report when i return.

Stef

[dnoize]

i promised last week i would check this in the aircraft and the results can be found here:

http://www.mycockpit.org/forums/showthread.php?p=80422#post80422



Stef


.

[Mr. Midnight]

im glad this subject was brought up, i however have not not gotten that far as to why , what and when they deploy.

i fly the level d and there is a lot to this plane and i have just now gotten to the point of understanding what the spoilers do beside slow the plane down.

first of all is the spoilers just flaps on the wing that go up too give more resistance to the plane helping slowing it down.

and when armed does that mean when the plane touchs down that deploys the spoilers.

and here is a dumb question do i hit the breaks as the spoilers ingage.

im not for sure even where to set the auto breaks.

is there a website where i can get this information on how and why and when to this or perhaps you good folks can help me in that area.

Thanks........Robert

[vidarf]

The spoilers are the thingies on the top of the wing that is raised. They serve three purposes:
1. Aiding the ailerons to bank the aircraft
2. Slightly raised for in-air speed reducing (increases drag)
3. Breaks the lift and add drag when landing

Here's a great source of information on this subject:
http://www.b737.org.uk/flightcontrols.htm#Spoilers_/_Speedbrakes

When the spoilers are armed, they will auto-deploy under given conditions. For example if the wheels has spun up and the right main gear strut is compressed (at least for 737).

If I'm not mistaken, the autobrakes is just that - AUTOmatic brakes. :) When the ground speed sinks below a certain value, the autobrakes is deactivated ("manual brakes"), or the plane will come to a complete standstill. No need to touch the brakes before you've switched off autobrakes.

As a curiosity: on the real 737, it is adviced that one keeps a light pressure on the brakes when autobrakes is disengaged, to make the transition smooth for the passengers. Not fun standing in the entry area greeting people with baggy trousers farewell... ;)

At least this is what happens in a 737, as far as I know.

The settings for autobrakes depends on the runway length, the runway condition, weight of the plane and so on. Just use the middle value until you get the feel of it - there are no brake disks that needs replacement in a sim! :)

PS: The website I'm linking to is a GREAT source. It is 737 specific, but much of the info is transferrable to other birds too.