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E-Jet Family-YV ILS landing

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Re: E-Jet Family-YV ILS landing

Postby tdammers » Thu Mar 26, 2020 9:21 am

I have mostly tested using the E190; it's possible that the E170, being smaller and lighter, requires different tuning parameters for IT-Autoflight.

I haven't looked into external model animations at all, but I have noticed a few bugs there myself, not just with the thrust reversers. For me, this has lower priority though; I first want to get the autopilot, PFD and MFD right.
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Re: E-Jet Family-YV ILS landing

Postby Figaro » Thu Mar 26, 2020 10:13 am

To be clear, it was much improved to the prior version, but still seemed a bit much. Have a spin in the E170 and suss it out? Maybe I'm just whinging :lol:

-S
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Re: E-Jet Family-YV ILS landing

Postby CFS03 » Thu Mar 26, 2020 7:57 pm

Wow tdammers, your fixes are really impressive! I noticed only one strange thing: the plane falls down below 155Knots. It's a normal thing or it is a bug? I don't know if it's a bug because honestly I don't know the speeds of this aircraft.
Bye and thank for your work,
Claudio.
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Re: E-Jet Family-YV ILS landing

Postby tdammers » Thu Mar 26, 2020 10:01 pm

Haven't looked at the FDM yet, but according to one source, a typical Vref is 135 knots with full flaps; in a clean configuration, 155 KIAS could very well be the aircraft's stall speed, so that does seem plausible. Small jets like these tend to stall rather aggressively; the CRJ700 is similar in this regard, if you fly it too slow on approach, it'll just drop out of the sky.
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Re: E-Jet Family-YV ILS landing

Postby CFS03 » Fri Mar 27, 2020 9:31 am

tdammers wrote in Thu Mar 26, 2020 10:01 pm:Small jets like these tend to stall rather aggressively; the CRJ700 is similar in this regard, if you fly it too slow on approach, it'll just drop out of the sky.

Ok, it's exactly what appened to me. Probably i have to use more flaps. Thanks for the advice!
Bye,
Claudio.
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Re: E-Jet Family-YV ILS landing

Postby CFS03 » Wed Apr 08, 2020 10:15 am

Hi tdammers, are you still working on embraers? I've downloaded the last version you released but i still have the problem of the approach speed.
I can't understand if I am using flaps well or not but with flaps above 15 degrees if I go below 160 Knots the plane crashes. With this plane (E175 in my case) it seems really absurd to have to approach the runway with such high speeds (in fact if I try to touch the ground it bounces off). I can't understand why with the original version I could do it and instead with your no (and you don't know how sorry I am). If you know how to use flaps could you tell me?
Thanks in advance,
Claudio.
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Re: E-Jet Family-YV ILS landing

Postby tdammers » Thu Apr 09, 2020 7:30 am

Yes, still working on it.

I made a small change to the FDM to get rid of the unrealistic pitch attitude, and this may have made a few other things worse, but the FDM was never realistic to begin with - I'm seeing climb rates of over 5000 fpm at sea level, and over 1800 fpm at FL410, which should actually be the service ceiling. Lots of metrics are wrong, too - mass balance, wheel positions, wingspan, etc. Needless to say, I'm not happy with this, and I'm currently redoing most of the FDM from scratch, based on a real FCOM and other resources, to see if I can do better.

For the approach, however, I can easily fly the aircraft down to 140 KIAS, and even airspeeds as low as 130 KIAS. Rough outline of the approach & landing procedure (assuming a standard ILS approach):

1. Reduce speed to 210 KIAS for the approach; verify ILS intercept heading and engage APP mode.
2. Capture the localizer.
3. Select speed 180.
4. At airspeed 200, select flaps 1.
5. At airspeed 190, select flaps 2.
6. As you approach the FAF, select speed 160.
7. At airspeed 170, select flaps 3.
8. Upon capturing the glideslope, lower landing gear, verify airspeed 160, and select flaps 4.
9. Verify autopilot mode, and dial go-around climb altitude into autopilot.
10. Select airspeed = Vref+5 (~145 KIAS)
11. At airspeed 155, select flaps 5.
12. If heavy, or a short landing roll is desired, at airspeed 150 select flaps full.
13. Before-landing checklist: clearance, 3 green, airspeed, ILS, PAPI, sink rate, flaps, autobrake.
14. Disengage autopilot and autothrottle at 500 ft AGL (or earlier, at your discretion). Autoland isn't calibrated yet and won't do a good job at landing the aircraft.
15. At decision height, call "land" or "go around" based on visual cues (alignment, PAPI, airspeed, sink rate)
15. 100 ft AGL (callout "one hundred"), slightly retard the engine
16. 50 ft AGL, fully retard and initiate flare
17. When the main gear touches down, engage thrust reversers. Spoilers and brakes should engage automatically. Use rudder and nosewheel to maintain runway centerline.
18. At airspeed 60 KIAS, disengage reversers.
19. Slow down to taxi speed, retract flaps, turn off landing lights, vacate runway.

For non-precision approaches (NDB, LOC, visual), the procedure differs slightly, but the rough idea is the same, you just use different cues. For a steep approach (e.g. EGLC), the order is a bit different, because you want to get configured and slowed down before the FAF, but other than that, the flap speeds are the same.
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Re: E-Jet Family-YV ILS landing

Postby CFS03 » Thu Apr 09, 2020 10:14 am

Thank you tdammers, i'll try your guide and i'll say to you if it worked.
Bye,
Claudio.
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Re: E-Jet Family-YV ILS landing

Postby tdammers » Fri Apr 10, 2020 8:02 pm

For those interested: I have redone the FDM's for the E170 and E175, they can be found here:

https://github.com/tdammers/E-jet-famil ... ee/wip/fdm

If anyone wants to give them a spin, I'd very much appreciate feedback. Performance should be more realistic, and I think they handle better than the original FDM, but more testing is needed. Once the FDM is good enough, I plan to re-tune the autopilot (it's not properly calibrated to reflect the updated FDM), and also do the E190 and E195 (those still use the old FDM right now).
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Re: E-Jet Family-YV ILS landing

Postby CFS03 » Sun Apr 12, 2020 11:29 am

Thank you tdammers, with your guide i managed to do a very good landing. My fault. I just needed to practice a little. Sorry if I made you waste time.
In any case, I tested your new version with the E175 and I didn't seem to see any problems for now so... great job!
Bye,
Claudio.
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Re: E-Jet Family-YV ILS landing

Postby tdammers » Sun Apr 12, 2020 4:31 pm

Someone else has already pointed out that the flaps aren't quite right yet, so I'm working on that. After this change, you should be able to land the aircraft with flaps 5 or 6, and Vref between 130 and 141 KIAS depending on weight. The version on my branch (wip/fdm) already reflects this, but it renders the -E2, 190 and 195 unflyable. Once that is worked out, I'll issue a PR.
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Re: E-Jet Family-YV ILS landing

Postby CFS03 » Sun Apr 12, 2020 6:33 pm

tdammers wrote in Sun Apr 12, 2020 4:31 pm:Someone else has already pointed out that the flaps aren't quite right yet, so I'm working on that. After this change, you should be able to land the aircraft with flaps 5 or 6, and Vref between 130 and 141 KIAS depending on weight. The version on my branch (wip/fdm) already reflects this, but it renders the -E2, 190 and 195 unflyable. Once that is worked out, I'll issue a PR.

Yes it is true, this problem is present but it is not as serious as I thought. One thing I noticed is that the difference between flaps in position 4 and 5 is very pronounced. It will probably be enough to make some adjustments and the problem should be solved.
Thanks for the work you are doing,
Claudio.
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Re: E-Jet Family-YV ILS landing

Postby tdammers » Sun Apr 12, 2020 9:04 pm

Hehe, yeah. I just checked the FCOM today, flap and slat positions should be identical between flaps 4 and 5, the difference is that flaps 5 also configures the aircraft for the landing (arms speedbrakes and reversers, and unlocks autoland). Anyway, what's on the branch right now should be a lot better already.
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Re: E-Jet Family-YV ILS landing

Postby Octal450 » Fri Apr 17, 2020 10:26 pm

Glad you enjoy the IT-Autoflight system --- let me know if you need any help hooking up the glareshield.

The SDK for ITAF is here: http://wiki.flightgear.org/IT-AUTOFLIGHT#SDK

Kind Regards,
Josh
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Aircraft I currently develop: MD-11, A320-family, Secret

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Re: E-Jet Family-YV ILS landing

Postby tdammers » Sat Apr 18, 2020 6:28 pm

I think I have most of it working nicely. Few details to iron out still, but it's mostly usable. One of the biggest things is that the labels for the various modes are different, so I need a bit of translation logic.
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