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Post by zfly2sky - bgan072 on Jul 19, 2009 19:25:41 GMT -5
Hey guys, good forum! I always wanted to talk "tweak tech" like this with somebody...Thank you for each and everyone of your expertise. Very common problem concerning the "over the panel view" Alot of the larger aircraft have such a high AoA and depending on how they are tuned, its a total crap shoot. I have fiddled with the "cruise_lift_scalar" in the aircraft config and usually it has it benefits. And a more simple way or "no brainer" trick I do is to lower the whole dang panel a quarter of an inch or so down the screne. I know, thats not too realistic but it still gives me a little bit more of a peak! I just wish there was a great big book that discloses all of the meanings and purposes of each line in the panel.cfgs, air files and model.cfgs plus if anyone knows what software necessary to "cipher" their "hieroglyphhics", drop me a line so I can be educated on their dern meaning....thanks for reading this and I appreciate all of you guy's detail and sincerity in this forum....really it is very informative! Thanks much.
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Post by Tom Goodrick on Jul 19, 2009 20:46:01 GMT -5
Welcome to our Forum. We always try to address a problem from all directions. But in this case your suggestion that the "cruise lift scalar" might help draws a negative reaction from me. The reason is that there is no such thing in real aeronautical engineering as a "cruise lift scalar" that adjusts the lift coefficient for a proper value during cruise. The problem is that, during cruise, the lift coefficient is very small compared to all other times in flight. The faster the airplane goes, the lower the lift coefficient must be. There is a standard aeronautical engineering formula that shows that is true. I don't know where Microsoft dreamed up that parameter. It has no place in a realistic sim. I always erase that that line from the tuning section (which leaves the value at 1 by default. In slow flight the lift coefficient is near 1 or somewhat greater. With flaps on a big plane, it could be near 2. But in cruise it shrinks to about 0.3 to 0.5.
If you want to exericise your calculator, the equation for airspeed in steady level flight is
KIAS = 17.16 * SQRT(W/S/CL)
This is often used to find the stall speed where the highest value of CL is used. (You'll find the value for a clean wing in table 404 of the .air file using an airfile editor.) There is a value for flaps in section 1100 that is added to that (adjusted for the percent of flaps extended).
We can turn that equation around and find the value of CL at any speed as
CL = 294.5 * W/S/KIAS/KIAS
Where W is total weight and S is the wing area (a reference value shown in the aircraft.cfg file under aircraft geometry). W/S is also noted by itself as "wing loading" in many aircraft specifications.
For a Skylane, W/S is 17.8 lbs/sqft. Stall speed clean is 54 KIAS. That gives CL = 1.79, Stall speed is 49 KIAS with full flaps. That gives CL = 2.18. The flap increment should be 0.39. At cruise the airspeed is about 135 KIAS. CL is 0.29. Should this be boosted or decreased? The big proble I have with that parameter is that this low range of the lift coefficient is very linear for almost all wings. Boosting it at this point would destroy that linearity.
A Beech 1900 commuter airliner with W/S = 54.8 psf would stall at 88 KIAS with flaps. That gives it a max CL of 2.08. It cruises at 180 KIAS. Then it would have a CL of 0.50.
A Learjet 35A has a W/S of 67.2 lbs/sqft stalls at 99 KIAS. Its CL is 2.019. At cruise its airspeed is about 220 KIAS. The CL is 0.41.
Again, why adjust this? It flies just fine with these values in FS. Of course, its true airspeed is 451 KTAS so it gets you there quickly.
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Post by hanspetter on Jul 20, 2009 12:17:35 GMT -5
Regarding living with the limited view I'm able to do that now. However, I had to disregard the VASI lights and never accept a red light until the last moment. That is, I'm above the glide slope until the last moment. If I try to maintain the right mix of white and red lights from far out I end up coming in too low. I haven't noticed this problem with a more generous panel view since then I'd just throttle up a bit before I touch without ever losing view of the ground. With the limited view there's no way to adjust for being a tad low without flying blind as the nose rises -- whenever I see red the only safe option is to go around, gain altitude and try again.
Are the FS glideslopes correct? It shouldn't be "unfixable" to find oneself slightly below the slope. This makes me wonder if the red should kick in before it actually does.
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Post by Tom Goodrick on Jul 20, 2009 21:35:48 GMT -5
I use the VASI lights as a guide when two to four miles out. Closer in I am looking at the runway. If the runway has an ILS, I use that also as a guide. But I have found several things. First, the VASI lights do not always agree with the ILS. Second either of these usually put you at least 1/3 down the runway. If you want to use an early turn-off, you have to go below the glideslope a little in good visibility. Of course you can do anything you wish in good visibilty. But when flying an ILS in IMC, you do not want to be below the glideslope because that is where hard things await you.
The most important thing to control tightly is airspeed. Use 1.3 x the stall speed for the weight and configuration you are flying. With gear down and full flaps at least two miles out, this is Vref to be held until you flare and cut power over the runway. If you know the field and are coming into a short runway, you'll be reducing power over the end of the runway and using a minor flare.
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Post by hanspetter on Jul 21, 2009 14:33:16 GMT -5
Two more questions,
1) What do you think of the standard 2D panel views of the stock aircraft? These are the ones all FS 9 user have in common. Even though we may not use them a lot it would be nice to confirm that they're OK or amend them for more realism.
2) Why do aircraft designers make aircraft with limited view? While all other modern vehicles tend to go for improved view the modern aircraft designs tend to provide no more or less. It would seem to be a safety issue to provide the pilots with an ample view even though they can learn to live with less. Even though a streamlined exterior calls for slanting windshields that follow the contours you can still increase the view by extending the windshield downwards. By using modern materials one can make a sturdy windshield of any size. And, a panel can be slanted too rather than looming straight up to the level of your sight line. It's evident that it could be designed for better view yet it's hardly considered for anything but trainers. Why is that?
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Post by Tom Goodrick on Jul 21, 2009 19:48:48 GMT -5
The default panels are old-fashioned and obsolete now but they weren't in 2003 when FS2004 was designed. Those panels are good and work fine if you spend the right number of hours getting to know them, the airplane and flying procedures in general. They worked ok for me in the over-the-panel view but you may recall I did yearn for a bit more visability. Everybody does. But as you work yourself up in experience levels (a pro would be spending at least 50 hours in each airplane before moving up to the next level of sophistication with a lot more time in the first twin, the first turboprop and the first fanjet. Most have 1500 hours before going to school for a jet rating. (Notice I said "going to school" where you get several days of ground school studying the aircraft and jet procedures, many hours of simulator work and a several hours of flight work to get into the right seat of a commercial airliner.
By then you don't need too much of a view of the approach. You are flying the approach by the numbers - starting altitude and airspeed, configuration changes along the way and airspeed managed tightly to the runway. You get enough cues to line up and touch down.
Until the 1960's cockpits in large aircraft were what ever was left over after they put in all the gear needed for navigation and flight management. With the new jet airliners they started getting serious about human engineering in the cockpits. I happened to have the opportunity to see two aircraft in advanced stages of design in September of 1973 when I toured Boeing and MCDonald Douglas as a guest of the US Air Force SPO out of WPAFB, OH. The two aircraft were the new jet transports competeing to replace the C-130. My job was to brief the people on the problems aircraft high lift configurations have on operation of extraction parachutes used for cargo airdrop operations. But I tagged along with the others at all areas visited.
One stop at Boeing was at a wooden mockup of the cockpit. Since they knew I was a pilot but of moderate stature (most Air Force guys are bigger than normal, the Boeing guy asked me to sit in the left seat and go through a series of tests. I was told to check and verify all instruments, reach all switches on the overhead, left side panel and at the bottom of the panel, exercise all controls in normal sequence for landing and to check visibility looking through the windows to a calibrated background screen. This mock up was setup so things could easily be moved around to check for interference from both seats reaching for things and to check view. It was interesting to see that considerable man-hours had been spent on this.
I remember mentioning to them a problem I had in a Cessna 150 ajust a few months earlier. I was making a gradual climbing left turn after takeoff and leaned far over to my right - losing all sight out the windows - to see the "Hobbs meter" (a meter that shows flight time by which we pay for the plane). In doing that i got vertigo for the first time in my life where I suddenly lost all sense of up and down. I had to force myself to sit straight in the chair and go strictly by the airspeed, altitude and gyron horizon to level the plane and then turn downwind. The Boeing guy said that was exactly what their concern was with some of the elements of the cockpit design. They try to put only seldom-needed gauges in hard-to-reach places.
McDonald-Douglas had a similar thing but I didn't get to sit in it.
The Mc Donald-Douglass aircraft became the c-17. I don't know the full story of what became of the Boeing but the Russians built a copy of it and that aircraft was successful for them. It used the Upper Surface Blowing for high lift into short fields just as Boeing had devised.
So I would say they do give the problem considerable deign effort. They just don't attach the same importance you do to a big expansive view. To minimize drag and yet carry all the stuff in the cockpit they need to, they have optimized the design.
With practice, you'll find most planes work fine with a reduced field of view compared to what you would prefer.
Then also we have the problem of comparing views in a simulator to views in a real aircraft. Human eyesight is very complex. The hardware in the eyeball plays only a moderate part. The brain does most of the work of perception and recognition. That involves training and knowing what to look for.
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Post by hanspetter on Jul 22, 2009 7:08:37 GMT -5
Thanks for an informative reply I do remember that you wanted improved over-the-panel view some time ago and set up panels that provided more view. That's why I found it a bit confusing when you went for less view this time. However, what all of us here want is the right view -- no more or no less. I guess we should choose other aircraft for sightseeing tours, aircraft that provide more view in real life. Airliners and bizjets are not built with scenic experiences in mind. However, most flightsimmers tend to assume that the sim view is more limited than it is in real life. Thus, most discussions will be based on the presupposition that we ought to be able to see more than we actually do. If this is not the case we'd better practice mastering what we've got. But then, there's always another "however" -- some custom panels are way too obtrusive because their creators want to show everything at the same time. When the panel covers more than 60 % of the screen vertically there's little left for viewing the scenery. Personally I don't feel a need to see throttles on the panel as long as I can see gauges that tell me the power setting. Vintage aircraft had messy cockpits with everything crammed into every space available. Modern aircraft are better in this respect since there are no ad hoc wiring, pipes and bulky gadgets all over the place. I like to handfly most aircraft, even the ones that would normally be computer controlled from start to finish. I use AP for cruise but I like to land all aircraft manually for two reasons, 1) I'm more interested in mastering the flight dynamics than I'm interested in learning to push the right buttons and 2) Any pilot should be able to save the day the old fashioned way if the electronics go awry. Some modern airliners may hardly provide this option while others do. That's a different discussion but it means that it makes more sense to handfly any Boeing aircraft than it does to handfly an Airbus. In any event, when the forward view is limited one must plan way ahead to stabilize the aircraft in landing configuration. No last minute upsets and phugoid can be allowed.
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Post by Tom Goodrick on Jul 22, 2009 9:12:39 GMT -5
You have summarized it well. I must admit that I have reservations about some of this. Last night I modified the Cessna 182 RG to fly with a reduced screen view (meaning more outside screen is hidden behind the panel). That aircraft has the problem that, sitting on the ground, it squats down on the mains so that the pilot's view is more upward and you see less runway. I had to increase the down angle from 2.0 to 3.0 degrees and could only set Y=2900, instead of 3000 as on other Cessnas. I wondered if this would ruin one of my favorite airplanes. It didn't. It seems in agreement with where the pilot's eyes are located. Her nose is just at the top of the cowling.
Of course real aircraft do have a seat height adjustment used by short pilots. I knew a very small woman who was less than five feet and under 100 lbs. She sat on a phone book. Her Cessna 150 climbed like a rocket when she soloed it.
I forgot to mention the main problem I have with default panels. I started putting "glass panels" in General Aviation aircraft when FS9 first came out. Today all aircraft made or modified (updated) in the US are given glass panels consisting of a Primary Flight Display (PFD) with graphical representations of airspeed, altitude and attitude and a Multi-Function Display (MFD) that includes a map, engine information, system information and a checklist. I just started using the PFD from the Learjet 45 and the map from the Garmin mounted in the middle of the panel. This is now commonplace. It makes possible smaller panels but those have not come yet except in new aircraft like the Eclipse and other very light jets. (I understand there is still a cooling issue that requires some space be left around components behind the panel.)
So for this reason I don't like the default panels and never use them. I do not like to fly old-style aircraft because I consider all the improvments in aviation in the past 50 years to be good ones. I have peeked into the cockpits of aerobatic and "warbird" aircraft at airshows and have seen plenty of Garmin maps used to help get the aircraft to the next show without getting lost and wasting fuel.
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Post by hanspetter on Aug 2, 2009 13:13:58 GMT -5
Airbus aircraft have an additional "under-the-panel-view" in the form of a camera mounted on the belly behind the front wheel. Passengers get this view on the entertainment screen during landings and it's also displayed on the pilots' panel.
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Post by Tom Goodrick on Aug 2, 2009 18:44:59 GMT -5
I doubt if the pilots pay much attention to it.
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robjeff
Member
Go Cubs Go
Posts: 15
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Post by robjeff on Aug 2, 2009 21:22:33 GMT -5
when flying the big iron the pros cant see the ground right in front of the a/c. that is why the marshallers stand to the left front when directing the planes into the gate. when ifr trust the glideslope. when it goes full deflection either way - go around. when flying vfr into an instrument runway watch and shoot for the white rectanglular boxes. if the runway is marked with the numbers, shoot for just beyond the numbers. on unmarked runways, including grass strips, pick a spot about 1/3 down the runway. if you are high the point will move away from you, too low it will move toward you. the vasi's are a reference only. in the rw many of the approach plates have notes that say the glideslope and vasi's don't line up. coming over the airport boundarry you should start transitioning to the flare. with proper speed control and power the a/c will settle onto the runway on the deired spot. i use the seat adjustment in rw a/c to keep from banging my head on the ceiling and to see over the glide panel. if you want to watch directly below you on landing fly a chopper or an ultralight.
rob j bgas054
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robjeff
Member
Go Cubs Go
Posts: 15
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Post by robjeff on Aug 2, 2009 21:24:31 GMT -5
when flying the big iron the pros cant see the ground right in front of the a/c. that is why the marshallers stand to the left front when directing the planes into the gate. when ifr trust the glideslope. when it goes full deflection either way - go around. when flying vfr into an instrument runway watch and shoot for the white rectanglular boxes. if the runway is marked with the numbers, shoot for just beyond the numbers. on unmarked runways, including grass strips, pick a spot about 1/3 down the runway. if you are high the point will move away from you, too low it will move toward you. the vasi's are a reference only. in the rw many of the approach plates have notes that say the glideslope and vasi's don't line up. coming over the airport boundarry you should start transitioning to the flare. with proper speed control and power the a/c will settle onto the runway on the deired spot. i use the seat adjustment in rw a/c to keep from banging my head on the ceiling and to see over the glide panel. if you want to watch directly below you on landing fly a chopper or an ultralight.
rob j bgas054
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robjeff
Member
Go Cubs Go
Posts: 15
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Post by robjeff on Aug 2, 2009 21:27:56 GMT -5
oops - my bad itchy finger
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Post by Tom Goodrick on Aug 2, 2009 22:15:19 GMT -5
robjef, we get all that and normally do it. But sometimes the FS panels give a very poor view over the nose on approach and sometimes they give too much of a view. This discussion pertains to how to adjust the 2D panel view so it is close to the real view.
Hans, I might be able to put a zoomed nose-camera view into the GPS map window. At least I can put a pop-up hole there and you can put a small zoomed forward "cockpit" screen into that hole using the "{" key. I have thought of doing such a thing for when using a twin for making scenic films.
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Post by flaminghotsauce on Aug 4, 2009 6:28:29 GMT -5
That would be cool. In X-Plane, the Mars jet has a forward view screen like that in black and white.
I need to investigate the panel configuration stuff in FSX. I downloaded a 182 that was FSX enabled but the panel blocks WAY too much view. I'm looking over the panel at probably a 30 degree angle into the sky. It looks like the view from the taildraggers.
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