Reverse thrust

[Damerval]

Hello,
I am trying to tweak the effectiveness of reverse thrust on jet aircraft. The default 737-400 that came with FS2K2 Pro is okay as far as that is concerned, but the freeware 737-200 has a much diminished (and unrealistic) reverse thrust to it. How do I change that? All I can see so far is a setting to determine if indeed there is reverse thrust available.
Any help will be greatly appreciated.

[Barney]

Search the Library for a utility program called "air edit". This will allow the opening of the *.air file for the particular aircraft [located in main aircraft folder]. Once opened, scroll to find the Reverse Thrust info and alter to your heart's content.

Hint: to start, I'd use a value that corresponds to another plane that seems to work to your satisfaction.

Final result will probably depend on trial and error.

[caine2b]

Try this (thanks to Tom Goodrick for this tip):

If you don't have the latest version of FDE that works on FS2002, get it (free from Abacus). Then go through all your jet .air files and change the Reverse Thrust percentage from -25.0 to -50.0. It will give you realistic deceleration when you engage reverse thrust after landing.

[Simon Evans]

What makes you say that the 737-200 is unrealistic..? The amount of reverse thrust that can actually be applied directly forward is about 20 per cent of total thrust in forward motion (directly rearward).
No matter what the throttle setting. No matter what the jet. No matter what type of thrust reverser is used.

It takes some very clever engineering to get jets to reverse the thrust flow and there's little demonstration of that cleverness in cascades and buckets - simple deflectors, cheap and reasonably effective.

In the Real World it's cheaper to make the runways longer than the planes stop quicker, which is why precious few jet airliners are made for short strips and of those that are, some don't even have thrust reverse (the BAe 146/RJ series, many of the Embraer ERJ's). The money and weight is saved for new brake pads...

Simon Evans

[Damerval]

Well, I don't know, maybe it is my own installation, but two things led me to conclude that the 737-200's reverse thrust was unrealistic. The first clue was when I landed on the Dutch Harbor (PADU) runway which I have seen 737-200's land on, touched down on the numbers yet barely managed to stop before the end of the runway - and that's applying brakes from down to 80 kts onwards. This led me to examin what was happening and I noticed that whether I applied reverse thrust or not did not change my deceleration rate once I touched down. I also remember from riding in a real one the profound sensation of deceleration felt when the pilot puts the reverse thrust on.
I do believe and appreciate the information you supplied - thank you for it. Light jets such as the 146 would not need reverse thrusters because they can land so slow, but heavies such as the A320-A340's, the 747's and 767's etc, as I understand, cannot brake on pads alone because of their enormous weight. Is that your take too?
I am like you admirative of the wonders of engineering deployed to provide reverse thrust from what would otherwise be strictly unidirectional by principle. But what amazes me most about modern jet engines is the continued performance they supply for the punishment they take. I have flown more often than I care to remember and yet never remember any engine failures. Whereas I have suffered one or two prop engine failures.

[Simon Evans]

Ah, I see...

The first thing to check is the calibration of your throttle - FS is a bit fussy about this and unless the throttle is fully at idle it won't engage reverse thrust. Calibrate the throttle using FSUIPC if you're in any doubt.
In fact, if you want to be clever you can even use FSUIPC to set the reverse thrust to work from the throttle, but that's not necessary to sort this.

OK, so assuming you are using the throttle as normal, get into the habit of retarding the throttle fully, then hitting F1 before hitting F2 and holding it on. The reverse thrust F2 button in FS works like a throttle in reverse - the longer you hold it the more reverse thrust you get (the engine may or may not spool up more, it depends on the sound file). To cancel reverse thrust just hit F1 again.

I would certialny try that before delving around inside air files - there is so much interraction in air files that one thing tweaked almost always changes fifteen other things.

Simon Evans

[Damerval]

FDE doesn't work on my system... it refuses to save once I have made a change, saying it can't open some kind of weird file that doens't exist and which I never pointed it to. Maybe it is XP that confuses it - I understand it uses the registry to find its babies.

[TK40]

Actually, contrary to popular belief, heavies like like 747/A340 don't require the use of reverse thrust on landing. The carbon brakes that they have are installed are extremely effective when used alone. More often then not, nowadays, airline policy dictates that whenever possible, the pilot should use IDLE reverse and rely on brakes only. Half to full reverse thrust can still be used but only on certain occasions on short or contaminated runways. This is done to save wear and tear on the engine. Older jets like 737/727/747 classic with less advanced brake systems tend to rely on reverse thrust more.

I've actually landed in a 767 where the pilot used no reverse thrust at all (not even idle reverse) and no spoilers. The brakes alone brought the aircraft to a halt.

TK

[mikeymcc]

The following remarks don't apply to FS but do apply to real jet transports ...

Brakes alone will stop the aircraft on "legal" runways -- this is a requirement for certification -- but the brakes have a limited ability to store the heat generated when they pull kinetic energy out of a moving aircraft. Even if the brake heat capacity storage limit isn't reached there can be a danger of a) tire fires and b) having the pads weld to the disks.

So while you might make one landing without reverse thrust as you just described, you probably would not get away with a series of no-reverse-thrust touch-and-go operations unless you allowed the brakes to cool by leaving the gear down in-flight.

And even that one landing without reversers was probably made at a very low touchdown speed and into a headwind -- either that or the pilot may have been violating his operating handbook with regard to managing brake temperatures.

Mike McCarthy

[mikeymcc]

Correction ... I meant "landing-to-full-stop" rather than "touch-and-go".

Mike McCarthy