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View Full Version : 737 Thrust Reversers..... how to do it?



kris
07-19-2007, 11:07 AM
Hello - my first post!

I'm currently building a 737 cockpit using Opencockpits IOcards and SIOC/On737 with FS9/FSUIPC... I am in the process of assembling the electronics for my throttle handles, and I'm wondering what the general concensus is for the thrust reverser setup. Some questions if I may....

-Is it possible to assign axes/switches to each reverser, or only one?

-Does FS9 only operate reversers as simply 'On' or 'Off', (in which case I only need a switch to close when the levers are fully moved) or can I apply reverse thrust gradually? In which case..... if I am able to assign axes and use potentiometer(s), does being able to apply the reversers gradually make a difference to realism (ie, is it worth the extra work)?

Sorry if I'm not making sense, or if this has already been discussed (I did search but couldn't find the info I needed).

Thanks in advance,
Kris

Bob Reed
07-19-2007, 11:26 AM
Hello and welcome Kris!! Good to have you with us!
Well FS 9 does not model the reverses very well I am afraid, but that said. Using FSUIPC yes you can assignee an axis and you can have a reverser for each engine. And yes when setup this way the more you apply the reverses the more effect they have.

Tomlin
07-19-2007, 12:20 PM
Speaking of reverse thrust, who here rembers back in FS98 how the reversers would actually back the plane up? I LOVED that feature, and although you were in danger of doing a cartwheel when you cancelled it, it was possible to do a 'power-back' from the gate in a MD-type aircraft. I learned about that from watching Northwest do it at their gates in DC-9s down in Jacksonville when I lived there. I really do miss this feature so much in FS9/X. Why would they have taken that simple feature out?

Back on topic, Bob- where do you feel that the reverse thrust is not modeled very well? In it's power, or reaction time, etc.?

ET

Michael Carter
07-19-2007, 12:27 PM
Power-back can be performed in the DF727 too.

Westozy
07-19-2007, 02:06 PM
Assign "Shift-P" to a button...

Michael Carter
07-19-2007, 11:18 PM
That takes all the fun out of three JT-8D's!;)

kris
07-20-2007, 05:14 AM
Cheers for the info guys - looking forward to figuring out how to put it all together now!!

spitfire9
07-20-2007, 01:09 PM
Yes,, by all means,, the Dreamfleet 727 will back up with reverse thrust.

I always thought you could do it with all the reverse thrust capable planes in FS9 ???

I'm pretty sure I've done it with some others.

kris
11-09-2007, 12:22 PM
Hi again guys...

Just a quick update and to say thanks for the advice- I worked out how to do it with my extremely limited electronics knowledge!

I basically wired 2 potentiometer in series on each throttle axis and set up FSUIPC to recognise the range of the first one as the throttle, and when the resistance is added from the second one, that is the reverser range! And it works like a dream!!!!

Sorry if it's basic and boring, but I was running around the room the first time those reverser indicators lit up!! :p

Kris

Tomlin
11-09-2007, 12:45 PM
Speaking of thrust reversers...

I am having a time with trying to get my throttle levers (especially reversers) designed for the LJ45. Even with the scale 1:1 drawings, it's a very tight fit and I am hoping to find a better way to link the reverser thru the main lever handle. If anyone has any info on how to connect these jokers, Im all ears. Ive tried extremely stiff (guitar) wire connected in the bottom of the rev. lever and running down between the layers of the main lever in a tight channel, but the wire is still not stiff enough to be reliable and it's too stiff to bend where it's inserted in the rev lever.

Im thinking a more mechanical solution may be required.

I have contempleted a roller switch, but I really want proportional rev thrust.

spitfire9
11-09-2007, 02:56 PM
Kris,, do you have a picture or something?

I'm not sure what you mean when you say wired the pots in series??

Sounds very interesting.

kris
11-09-2007, 03:43 PM
Kris,, do you have a picture or something?

I'm not sure what you mean when you say wired the pots in series??

Sounds very interesting.


Sure - I'll try and explain with my limited knowledge...

I'm using iocards and SIOC. With an analog axis input the software converts the resistance of the potentiometer into the offset value for FSUIPC.
http://i219.photobucket.com/albums/cc67/krisspur/reverserschem.jpg
Connecting the 2 potentiometers in series like I have means that the input sees a total resistance of 14.7k (instead of separate 10k and 4.7k). When I pull the throttle slider to idle it closes and offers no resistance, but the reverser rotary is still fully open and showing a resistance of 4.7k. This is the idle point on FSUIPC.

When I turn the reverser pot the resistance drops to 0 ohms, which sends the reverse range to FSUIPC for proportional reverse thrust. It works perfectly!!! Hope that's clear.

Kris

737NUT
11-09-2007, 04:03 PM
Speaking of thrust reversers...

I am having a time with trying to get my throttle levers (especially reversers) designed for the LJ45. Even with the scale 1:1 drawings, it's a very tight fit and I am hoping to find a better way to link the reverser thru the main lever handle. If anyone has any info on how to connect these jokers, Im all ears. Ive tried extremely stiff (guitar) wire connected in the bottom of the rev. lever and running down between the layers of the main lever in a tight channel, but the wire is still not stiff enough to be reliable and it's too stiff to bend where it's inserted in the rev lever.

Im thinking a more mechanical solution may be required.

I have contempleted a roller switch, but I really want proportional rev thrust.

Doesn't do much good to worry about proportional rev thrust if the sims don't model it well. Just my opinion. I have already been doen this road with old real 737 throttle i had. It slowed the same whether it was idle reverse or full reverse so i just put a microswitch on it and called it a day. :)

kris
11-09-2007, 05:08 PM
From my point of view, the sim that I'm currently building is going to last me a while, not just for the current software that doesn't model the reversers well (it better had, the amount of time I'm putting in!) In a few years there will be a software version that models everything perfectly, and my sim will be waiting just to plug in!:D