PDA

View Full Version : so whens the best time to deploy thrust reversers?


Ultralights
31st Aug 2005, 12:23
well? is it immediatly after the main gear touch the tarmac? or beginning of the flare?

http://photos.airliners.net/middle/9/7/4/605479.jpg

montys ex teaboy
31st Aug 2005, 12:49
As soon as the mains touch, never before. Probably contrary to some A/C and Company SOP'S.

Dassault of France, on some models of their A/C (if not all) don't allow you to engage reverse until the nose wheel touches (nose wheel switch). Not quiet sure of their reasoning on that one, nor a lot of other things the French do.

A lot of companies won't allow TR to be deployed until the nose wheel is on the ground. The reason they give is in the event of an asymmetric reverse you would have a better chance of directional control. To me, the speeds we are talking about before the NW touches most, if not all, the directional control would be via the rudder. Granted, in a high nose attitude situation the rudder would be less effective due to "blanketing".

TR effectiveness is proportional the air speed. So by the time the nose wheel is "flown on" gently as it should be, it is almost too late for the reverse.

VitaminGee
31st Aug 2005, 12:49
When the lady says NO - and means NO!! :E :O

Shaggy Sheep Driver
31st Aug 2005, 12:50
In some cases (the Trident was one), they can be deployed in flight, as well.

SSD

BlueEagle
31st Aug 2005, 13:08
Under certain high nose conditions in rear engined aircraft it was possible to deploy reverse thrust and risk sitting the aircraft on its tail with the reverse vector so delaying until the nose wheel touched down was considered a way of avoiding this possibility.

Not sure but think the DC9 may have been a candidate.

419
31st Aug 2005, 13:11
wasn't there an accident a while back, (airbus I think), which was caused by the thrust reversers operating during flight?.

If I have remembered this correctly, is it still possible for this to happen, or have they all be modified to prevent it re-occuring

Onan the Clumsy
31st Aug 2005, 13:12
I had a sand rail once (an off road vehicle) and it had independent rear brakes. That allowed for very tight turning. Why not allow in air deployment of individual TRs to decrease the turning radius of a FJ? It'd be like VIFfing.

...or should I ask this in Questions :confused:

haughtney1
31st Aug 2005, 13:38
When your on the mains......before the nosegear touches..as per Boeing FTM:)

UniFoxOs
31st Aug 2005, 14:08
419, don't you mean this one (http://en.wikipedia.org/wiki/Lauda_Air_Flight_004) - I believe they have been modified since.

419
31st Aug 2005, 14:27
That's the one. Thanks Uni...

My apologies to Airbus.

airship
31st Aug 2005, 14:27
Use of reverse thrusters in-flight is only mandatory when reducing speed from high warp-factors. Otherwise, I'd suggest you just relax and let the tractor-beam take the strain :ok: Here's where I'm coming from (http://media4.big-boys.com/content/galaxies1.wmv) (WARNING: large file!) :O

However, you should be aware of certain dangers when using thrust reversers too rapidly after traversing blackholes and other space/time port phenomena. One of these is being ambushed by the tractor-beam of a Star Destroyer. The immediate signs of the existence of a tractor beam will be illumination of the orange "AUTO FAIL" and the "OFF SCHED(uled) DESCENT" accompanied by a warning klaxon:

http://www.b737.org.uk/dcpcspanel.jpg

(NB. The panels on more recent craft may differ slightly.)

Tractor beams take some time to attain full power, so my best advice if you're able to catch an early-warning would be to forget about the reverse thrusters and instead apply 110% full-forward thrust directly at the enemy vessel. I believe that this technique was originally devised by an ancient Earth-based civilisation and was called the "crazy Ivan". This technique if used early enough, may be sufficient to confuse the bio-electronic computers controlling the tractor-beam causing it to reset and allowing your escape. (NB. Failure of the tractor beam does not equal failure of the "defense shield" around the Star Destroyer...!)

May the force be with you! :)

Foss
31st Aug 2005, 14:41
sorry to but in, but can someone tell me why when I open this thread, and sometimes others, the postings are about 3 feet wide.. while others fit in the 'puter screenthe way they're meant too.
it's a bit bloody annoying :suspect:

airship
31st Aug 2005, 14:50
Sorry about that Foss, I didn't post the original picture in R&N though! I think it's because of the monitor / screen resolution you're viewing through. Mine's a 19" @ 1152x864 pixels. But I've had similar experiences too. So if you're prooning on a small screen on a low resolution then that might explain it. One can only assume that some JB'ers are big spenders on monitors or else don't worry about fitting photos into a "reasonable" space before posting...?! :8

rubik101
31st Aug 2005, 15:27
Nice picture! Can the 747 deploy reversers in the air? Maybe it's just the paint job!

gas path
31st Aug 2005, 16:12
Rubik

...er no, well not intentially:suspect:
'tis a fairing that needed a paint job!

Foss
31st Aug 2005, 19:16
cheers airship. thought it was something like that
(not my computer, I'm doing a burgalry)