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787 and CRJ-200 Development

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Re: 787 and CRJ-200 Development

Postby skyop » Sat Nov 27, 2010 8:14 pm

nickyivyca wrote:The 787 cockpit problem is a known thing-I just have to modify the select animations, or switch to a distance one. Or I was thinking...So in the views in the setfile, I was thinking that you could add a couple props to them. There already is an internal property, but I don't know what else that's used for.


Yes, I used the internal property for sound and instrumentation on the CRJ900. It worked fine. ;)
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Re: 787 and CRJ-200 Development

Postby dany93 » Sun Nov 28, 2010 12:23 am

nickyivyca wrote:On approach with 15% fuel and full flaps, I had a negative AoA. This was the most alarming.

With about 15 % fuel (Gross Weight 322 000 lb), full flaps, at 133 KIAS (approach speed), I have a positive AoA of 0.6 deg. AoA becomes -0.05 deg (still close to zero!) at 140 KIAS. For specified conditions ( http://www.lissys.demon.co.uk/samp1/index.html : 35 % fuel, Gross Weight 365 000 lb, 133 KIAS), I have 1.5 deg. Moreover, I think that this AoA is not the true one with flaps, because it is likely given for the wings geometry with zero deg flaps (not sure of this, but seems plausible too when observing AoA and pitch angle together, with full and no flaps). If I'm right, the true AoA with flaps extended is well higher. Do you have anything about how much this AoA should be? I have none, I've only kept your initial value (0.5 deg set in 787.xml FDM, but changed: 35 % fuel and 135 KIAS) in the FDM for my lift and drag adjustments.
I also saw that the AP took a bit of time to pull me to the right position during the climb.

The slow response to take the climb rate after takeoff is due to low speed (around 150 - 180 KIAS). Unfortunately, I ignore the real aircraft behaviour, but what to do? If we push the A/P gain up (by how much?) only for reaching climbing more rapidly after takeoff (still at low speed), it will harden again the reactions to A/P at high speeds, which is often a problem with YASim FDM (although this one has become correct enough, but still more rough for pitch than usual JSBSim ones, which are, for me, closer to reality). I'm personnally satisfied with its high and moderate-speed pitch behaviour when we change A/P altitude setting, and this slow response doesn't disturb me. Do you really think it has to be, or can afford to be (for your remark), modified?
Also, I was told that for real aircrafts:
- even airliners (like small aircrafts) do a short step at levelled flight just after takeoff, to reach a given speed (security, in case of an engine failure)
- autopilots avoid abrupt changes in attitude to prevent passengers nausea.
(I admit that's a bit short for the complete procedure.)

You've found a good compromise for the gear rotation when compressed. Also, the engines are running after reset. This is more convenient, specially for tests (sorry, skyop :) ).
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Re: 787 and CRJ-200 Development

Postby nickyivyca » Sun Nov 28, 2010 1:04 am

One thing...

http://www.boeing.com/commercial/airpor ... speeds.pdf

This document shows approach speed at 140, which I was using on approach. The problem with the info that we have is that it's not from the flight tests, it seems. So constructing an FDM from incomplete info is going to be quite hard.

The page wrote:December 2008: B787-8 model released:

The Piano-X model of the Boeing 787-8 has now been released in the public domain and can be downloaded freely, see release note here. It is fully adjustable and supersedes this original sample analysis, which will no longer be updated.

So the info on that page is only valid in 2008, not in 2010 like now. What I'm looking at is to have a non-finalized but pretty good FDM and AP for a front-page, 2.1-ready release by Christmas. Then we'll work on the FDM as real life 787 reveals more information and I'll work on the cockpit.

As for the AP, I think it actually did decently well for pulling me up on takeoff. But I'll need to run that kind of thing again.
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Re: 787 and CRJ-200 Development

Postby dany93 » Sun Nov 28, 2010 2:41 pm

What I'm looking at is to have a non-finalized but pretty good FDM and AP for a front-page, 2.1-ready release

I completely agree with this point of view. Again, even as it is, even not perfect, this aircraft is very nice and pleasant to fly.

Some thoughts about elevator trim for climbing after taking-off (80 % fuel, flaps 0.5, climbing 2000 ft/mn):
Real procedure consists in presetting elevator trim before taking off. For this aircraft, a preset of about -0.2 (trim up) seems a good start. Later, this value has to be progressively adjusted for current conditions (I have +0.07 for 350 KIAS at 3000 ft, and so on). Autopilot does it itself, but it should be done by the pilot in case of manual control. Elevator trim preset could probably be done at start by 5 lines in 787-set.xml, but I'm not in favor of this solution because people who do not use trim setting (sure there are....) or AP will be uncomfortable later by this permanent trim up.

A small thing:
Before the release, we'll have to "clean" the files from useless comments and other things. Will you do it at last time or would you prefer me to upload (when?) an aircraft Folder with my comments deleted? From memory, lines in comments from me can be found in 787.xml (FDM), 787-set.xml, and 787-autopilot.xml.
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Re: 787 and CRJ-200 Development

Postby skyop » Sun Nov 28, 2010 4:57 pm

I had another look at the 787 today, and some of the animations are bugged up. It looks like you left out some flaps in the wing flex animation, the nosegear spins incorrectly and the left main gear has a clone! :?

I tried to turn off the engines by pressing that button; they spooled down, then went right back up to running!
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Re: 787 and CRJ-200 Development

Postby nickyivyca » Sun Nov 28, 2010 7:49 pm

skyop wrote:I had another look at the 787 today, and some of the animations are bugged up. It looks like you left out some flaps in the wing flex animation, the nosegear spins incorrectly and the left main gear has a clone! :?

I tried to turn off the engines by pressing that button; they spooled down, then went right back up to running!

Did you use the cockpit development version (787-8.xml)? I accidentally switched it to use the old .ac file that has some clones in it from old animations. That's probably also the reason for the missing stuff in the wingflex animations, I deleted all animation info for the clone objects. The main file (787.xml) is correctly matched with the .ac file. I'll look into the engine startup problem, for now try clicking the knobs as well.

dany93 wrote:Some thoughts about elevator trim for climbing after taking-off (80 % fuel, flaps 0.5, climbing 2000 ft/mn):
Real procedure consists in presetting elevator trim before taking off. For this aircraft, a preset of about -0.2 (trim up) seems a good start. Later, this value has to be progressively adjusted for current conditions (I have +0.07 for 350 KIAS at 3000 ft, and so on). Autopilot does it itself, but it should be done by the pilot in case of manual control. Elevator trim preset could probably be done at start by 5 lines in 787-set.xml, but I'm not in favor of this solution because people who do not use trim setting (sure there are....) or AP will be uncomfortable later by this permanent trim up.

I think we shouldn't have the trim preset. Based on cockpit photos of the real thing, I don't see any trim levers so I don't know how this would be done in real life.
dany93 wrote:A small thing:
Before the release, we'll have to "clean" the files from useless comments and other things. Will you do it at last time or would you prefer me to upload (when?) an aircraft Folder with my comments deleted? From memory, lines in comments from me can be found in 787.xml (FDM), 787-set.xml, and 787-autopilot.xml.

You should delete the unneeded comments from the FDM and AP, I can deal with all of the other stuff. I'll also probably be combining animations, as the model xml file had about 100 KB (nearly half) of its contents redundant because I could combine each segment of the wingflex animations into one blob. The light animations were also partly like this. I'll also clear out the overly large pile of old autopilots in the Systems folder, and also remove things like the 2-d panel. I'll also take out the other cockpit-dev file.
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Re: 787 and CRJ-200 Development

Postby dany93 » Mon Nov 29, 2010 6:34 pm

I've cleaned 787.xml (FDM) and 787-autopilot.xml from the lines that I'd added in comments.
This file: 787112610-V02 http://www.datafilehost.com/download-68684cac.html

In the autopilot file, I've left two sets of inactive lines which were already in it before (may be kept for later?):
- one set under "Prediction filters", of which "nav1-track-error-lookahead-deg" is not used below in the AP file ("nav1-track-error-deg" is used),
- second set "Second Stage #2 drives the rudder." which is commented inside brackets.
Out of curiosity, I've started testing the effect of "Prediction filters" on LOC alignment in approach. Doesn't seem better, I prefer to observe this for enough time before maybe introducing it in AP, if it gives too much yaw overshoot or oscillations in its current version (does not seeem to be the case).

Maybe you already have this:
http://www.bristol.ac.uk/aerospace/msc/ ... ysheet.pdf
Among other things, I (hope to) understand:
Approach Speed (MLW) 133 KCAS ((?? no date)
Flap (Slat) Deflection - Takeoff (Highest) 20 (22)
Flap (Slat) Deflection - Landing Configuration 30 (-)
Auto Pitch Trim Descr.: trim via variable incidence THS (I presume Tail Horizontal Stabilizer)
On some airliners (B 1900D), pitch trim is manually adjustable by a vertical wheel, on some small aircrafts by a button on the U-shaped yoke. Difficult to think there is no manual control available. However, it changes nothing about no automatic preset before takeoff, as already said I agree with you. But that makes things more enjoyable for flying in manual control (rare in real life, not so in FG).

Another thing (about the vertical speed indicator)
The drawing figures are good ! But the vertical speed scale is not linear.

Image
from http://www.youtube.com/watch?v=aXkH49LB ... _embedded# (and you are at home)
Listen at time 4:25 in final approach. Don't they say 122 knots ?
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Re: 787 and CRJ-200 Development

Postby nickyivyca » Tue Nov 30, 2010 12:55 am

My guess is that the trim is controlled by the flight computer, or maybe a separate switch, controls the trim.

dany93 wrote:from http://www.youtube.com/watch?v=aXkH49LB ... _embedded# (and you are at home)
Listen at time 4:25 in final approach. Don't they say 122 knots ?

They said 152 knots. So on a single-engine landing, that's pretty low, so I guess it would make sense that the approach speed is pretty low. I'm not more inclined to trust 133 knots now that we have two sources with it, and yet another that places the two-engine approach at that level.
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Re: 787 and CRJ-200 Development

Postby dany93 » Tue Nov 30, 2010 5:00 pm

Sorry, maybe because of my english I'm not sure to, or don't, understand what you mean.
1) Do you mean that the approach speed on a single-engine aircraft must be higher than normal, thus that the normal approach speed is likely rather low (that I would say) ?
2) You're not more inclined to trust 133 knots ? Or: You're now more inclined....? If not, which value are you inclined to trust now ?
Thanks
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Re: 787 and CRJ-200 Development

Postby nickyivyca » Tue Nov 30, 2010 10:18 pm

Well, for the single engine approach...They normally use less flaps and a higher speed for a lower amount of drag. So if 152 knots is the faster approach speed, that's only 12 knots above what might be a normal approach speed at full flaps and both engines. So it does make sense to have a low approach speed.

And now that I've seen more resources that show 133 knots and the single engine's 152 knot approach speed, I'm more inclined to believe that 133 knots makes sense. We'll need to test cruise performance (climb and service ceiling) because the approach part of the FDM may have messed with the previously pretty good performance in upper altitudes.

IMPORTANT QUESTION ABOUT LIVERIES:

So currently the mapping on the CRJ-200 and 787 includes very little room for detail on the wings. I was considering making a completely separate mapping file for the wings that is fully 2048 x 1024. This could create confusion, though, because livery makers could put textures on the original wing textures and have them not be there. My plan is to add this to both aircraft after the front-page releases are made. Then I could have an experienced texturist make some dirt and path textures for the wings. I will probably do the wings, but what about the hstabs? They're not seen out of windows, so...

Some of the latest info: Paintkit for CRJ-200 is mostly done. Just need to write the textfile to include parts about the paintkit. Paintkit for 787 has been modified, I'm still tweaking the mask-based light system (instead of the old one, which gave bad-looking results). But I'm having a really weird problem. On the 787 (only!) the beacon lights are out of place. I tried fixing the problem by moving them to their intended location in the base .ac file (they were originally stored at the origin and moved to their correct place with an independent translate animation). I think the problem is still happening, even with the billboard animations removed (billboard makes a flat object rotate to be seen from all angles, I think). I'll post a release with the problem happening to me tomorrow, hopefully. The CRJ-200 is nicely ridded of problems, including the problems introduced with adding the copilot view and the props created that go along with it. I may have also tweaked the FDM between the last release and this one, probably going to run some cruise performance tests on it before a release.
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Re: 787 and CRJ-200 Development

Postby nickyivyca » Thu Dec 02, 2010 6:28 am

CRJ-200 Release!

http://www.mediafire.com/?4jkklmbpcd7z3h9

And this isn't just any release. If there aren't any problems with it, I'm hoping to have it uploaded to Git and added to the main page, or maybe have it put in the queue for the 2.1 page.

The official list:
-Fixed the PFD in Copilot view.
-Finished the prop-based view selection and sound
-Added a tiny bit of elevator power, some other FDM tweaks
-Fixed the problem with .6 on autobrakes by using (ABRAKE > 5.9 and ABRAKE < 6.1) instead of ABRAKE == 0.6. The fix is compatible with versions after 1.9.1, as it only seems to occur in 1.9.1.
-Paintkit: http://www.mediafire.com/?xiq7kii8qhivr7m
-Took out a lot of extra junk and converted all .rgbs to .pngs. Notice how much smaller this zip file is compared to other releases.

The only thing I didn't test was cruise performance with the service ceiling, though it didn't seem to make a difference when I was flying around some short flights.

787 stuff:

I've been working on a light map (as well as a couple other liveries, like this one) Here's the current progress on the Qantas livery and the lightmap:

Image

I may be cutting out new fuselage light areas to accommodate for the slight cutting off that's appearing. They look a bit small to me. I will move the nosegear light mask template piece farther away to remove some of the problems I've been having with cutting off of the edges. The vstab lights seem decent to me, they're kinda hard to see in the pic. The winglights seem a bit dim, though. I'll try masking them on top of white instead of the darker wing color to brighten them up a bit.
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Re: 787 and CRJ-200 Development

Postby skyop » Sat Dec 04, 2010 7:33 pm

Some tiny issues I noticed with the latest CRJ200:
  • The electronic instruments now display in Copilot view but the backup instruments in the center still disappear
  • The main wheels are just off the ground a little

Other than that everything looks good! :)

EDIT: The controls seem a little spazzy at high speeds.
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Re: 787 and CRJ-200 Development

Postby nickyivyca » Sat Dec 04, 2010 8:33 pm

What defines high speeds? Because they're not going to be too happy moving along at more than 300 KIAS, probably.

The only other things I want to work on are testing the service ceiling, and also editing the splash screen to include more of the picture. But those things may be delayed until mid next week because both of my laptops aren't working properly, and I have a school project to work on.
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Re: 787 and CRJ-200 Development

Postby skyop » Sat Dec 04, 2010 8:52 pm

nickyivyca wrote:What defines high speeds? Because they're not going to be too happy moving along at more than 300 KIAS, probably.


I did a low pass at about 270 KIAS, and the plane went crazy with just one tap of the aileron.
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Re: 787 and CRJ-200 Development

Postby nickyivyca » Sat Dec 04, 2010 9:09 pm

I can tone down the ailerons, I guess. Are the elevators good, though?
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