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Guest jshyluk

Runway slopes and takeoff performance

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Colleagues,One of my local airports has a longitudinal runway slope in excess of 2 degrees, so i'm after some info on how FSX (I'm still largely bonded to FS9) models such things. Therefore:1/. Does the standard terrain mesh of FSX show up runway slopes (in any direction) in general?2/. Do any of the add-on meshes around improve the situation?3/. To what extent (if any) does FSX - or any of the more advanced airliner add-ons available - model the difference in take-off performance for an uphill or downhill slope?4/. While I think of it, how about the differences experienced between wet and dry runways?Your thoughts appreciated,Andy

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>1/. Does the standard terrain mesh of FSX show up runway>slopes (in any direction) in general?No, all FS2004/FSX runways are flat, due to the flatten situation inherent to all MSFS editions to date.>2/. Do any of the add-on meshes around improve the>situation?Given the above, no - add on meshes do not influence the terrain within the airport boundaries.>3/. To what extent (if any) does FSX - or any of the more>advanced airliner add-ons available - model the difference in>take-off performance for an uphill or downhill slope?Given the above, no MSFS sims have any slope influence. That said, while I know several high fidelity airliner simulations allow you to enter the slope degrees in the MFC for takeoff thrust calculations, I highly doubt they are "interactive" and will have a bearing on your airplane performance. >4/. While I think of it, how about the differences>experienced between wet and dry runways?I have skidded a bit more on wet runways vs. dry, but other than that I can't speak to differences. Enjoy,-Greg

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I thought some payware scenery have sloped runways? Of course they aren't the standard runway texture but they are just the underneath texture. (I think if the scenery is based on round-earth or something like that)Here's the scenery I'm thinking of:http://www.llhinfo.com/lflj_en.html

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Aerosoft's Lukla has a sloped runway as well. I don't think the slope has any effect on the aircraft though.

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I made a sloped runway once in FSX. It worked great for the user aircraft, but AI would not use it. I think that is the main reason why we don't see more of them. It seems to me to be most suited for small GA fields where no AI are needed.RhettFS box: E8500 (@ 3.80 ghz), AC Freezer 7 Pro, ASUS P5E3 Premium, BFG 8800GTX 756 (nVidia 169 WHQL), 4gb DDR3 1600 Patriot Cas7 7-7-7-20 (2T), PC Power 750, WD 150gb 10000rpm Raptor, Seagate 500gb, Silverstone TJ09 case, Vista Ultimate 64ASX Client: AMD 3700+ (@ 2.6 ghz), 7800GT

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>3/. To what extent (if any) does FSX - or any of the more>advanced airliner add-ons available - model the difference in>take-off performance for an uphill or downhill slope?You could quickly experiment on your own to find the answer.Take some small aircraft like C172 and perform some take-offs from roads or desert areas where terrain is visibly sloped. See if you notice any difference. If terrain is really sloped and the physics is done right you shouldn't even be able to taxi up the hill. I know I had done it before but I forgot what the conclusion was.Michael J.http://img142.imageshack.us/img142/9320/apollo17vf7.jpg

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>>You could quickly experiment on your own to find the answer.>>Take some small aircraft like C172 and perform some take-offs>from roads or desert areas where terrain is visibly sloped.>See if you notice any difference. If terrain is really sloped>and the physics is done right you shouldn't even be able to>taxi up the hill. I know I had done it before but I forgot>what the conclusion was.>Those hills, outside airport boundaries do work. I've often rolled down hills in GA aircraft to build airspeed and glide away.....just like a video circulating on You Tube recently. Going uphill, the aircraft will decelerate, as it should.L.Adamson

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Thanks to all for their replies. I like the one about attempting to taxi/take-off on hills outside the airports to see if the physices is modelled. The question is: why CAN'T we have sloping runways at airports? Seeing as they exist in the real world.... At least if it looked as though it sloped regardless of whether or not it made a difference that would be a start. For correct ops with airliners, slopes + wet/dry surfaces do make a difference. At the airport I mentioned for example the uphill r/w is very definitely limiting when approaching maximum weights for the a/c that use it.To expand my original post a bit: If FSX does not give these advanced features for us hard-core types, what DOES it give over an FS9 with all the add-ons (scenery, meshes etc) when considering airliner simulation? (Let's ignore "eye candy" and fancy views for now....) Better pressurization model for example? Runway friction coefficient?? Etc.Any thoughts anyone? AndyPS I'm throwing the gauntlet down here. Come on guys, persuade me!!

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>Aerosoft's Lukla has a sloped runway as well. I don't think>the slope has any effect on the aircraft though.Don't stop on the runway without your parking brake set then! :-lol Even with the parking brake, some a/c will still roll downhill 'cause their brakes are weak... *:-* As to the OP's question "why not," that's pretty simple to answer. ACES simply ran out of time to fully convert all the necessary code to allow for airport runways, taxiways, and aprons to work with the completely new, "round earth" paradigm.

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@Andy:What if you threw down a gauntlet, and nobody was there for you to fight with? That looks to me kind of what you are doing.Firstly, I would suggest that most of the improvements of FSX over FS9 are "fancy views and eye candy", things including improved textures, lighting, a large increase in the number of visible polygons, and a vastly improved terrain mesh out of the box. The trouble is that sometimes the eye candy has very practical values, and sometimes it's just really pretty. I can't fathom where you stand on the subject, so it seems to me pointless to lecture to you on it. "Eye candy" comes with a price in frame rates, too. Without knowing how you prioritize having pretty scenery versus smooth frame rates, there's also very little I think we can usefully discuss.FSX seems to be geared towards low-level GA flights and adventure flights that don't use up a lot of scenery (in the Missions). In fact in terms of pure content, I would suggest that it's the Missions that make FSX really stand out over FS9.But if you don't want missions, and all you want to do is fly airlines, then FS9 is probably better. There have been some good airline add-ons recently for FSX, but I don't have any of them, so I can't compare them to say the PMDG 737NG. Maybe if you are into virtual air traffic control, such as VATSIM and others, FSX is better, but I know very little on that score. Then there's X-Plane: maybe that's more to your liking.What I can definitely tell you is that there is no law or rule against owning and using more than one flight sim. If you prefer one over the other, then by all means go for it. I think that FSX, FS9, and X-Plane each represent great value for the money, if you are an avid sim-pilot. Each has its own strengths and weaknesses, none will break your budget (at least until you get hooked into add-ons and peripherals...)Jeff ShylukAssistant Managing EditorSenior Staff ReviewerAVSIM

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>To expand my original post a bit: If FSX does not give these>advanced features for us hard-core types, what DOES it give>over an FS9 with all the add-ons (scenery, meshes etc) when>considering airliner simulation? (Let's ignore "eye candy">and fancy views for now....) Better pressurization model for>example? Runway friction coefficient?? Etc.>>Any thoughts anyone? >>Andy>>PS I'm throwing the gauntlet down here. Come on guys,>persuade me!! Runway friction coefficiency? Please don't take my comments to be anything more than what they are, but unless you have your ATPL or an advanced degree in physics, how in the world are you going to know if any of your desired features, for the "hard-core types", are accurate or not?

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>>As to the OP's question "why not," that's pretty simple to>answer. ACES simply ran out of time to fully convert all the>necessary code to allow for airport runways, taxiways, and>aprons to work with the completely new, "round earth">paradigm.I was thinking about this, and almost responded yesterday, but didn't. I can't resist responding Bill, with my thoughts on it:If this can be implemented for FS11, it would imo be a great step forward. If it cannot be implemented in FS11, it won't break my heart.That's all I wanted to say on it :D (I like to think about the future of the sim)RhettFS box: E8500 (@ 3.80 ghz), AC Freezer 7 Pro, ASUS P5E3 Premium, BFG 8800GTX 756 (nVidia 169 WHQL), 4gb DDR3 1600 Patriot Cas7 7-7-7-20 (2T), PC Power 750, WD 150gb 10000rpm Raptor, Seagate 500gb, Silverstone TJ09 case, Vista Ultimate 64ASX Client: AMD 3700+ (@ 2.6 ghz), 7800GT

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>>As to the OP's question "why not," that's pretty simple to>>answer. ACES simply ran out of time to fully convert all the>>necessary code to allow for airport runways, taxiways, and>>aprons to work with the completely new, "round earth">>paradigm.>>I was thinking about this, and almost responded yesterday, but>didn't. I can't resist responding Bill, with my thoughts on>it:>>If this can be implemented for FS11, it would imo be a great>step forward. If it cannot be implemented in FS11, it won't>break my heart.>>That's all I wanted to say on it :D (I like to think about>the future of the sim)Well, it's obviously far too early to form any type of conclusions yet, but consider the following known facts carefully:1. Train Sim 2 is being programmed to use the same core platform that will also be the foundation for FSvNext.2. Everything in TS2 is anchored to the ground, so obviously will have to conform to the "round earth paradigm" precisely.3. TS2 will be released at least a full year before FSvNext.It would therefore seem reasonable to hypothesize then that this same solution will be useful for ground objects such as airports in FSvNext. :)

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"Where are we with higher altitude t/offs on baking hot days for example? (This maybe getting a bit out of control here -!!- but I trust you are getting the sense behind the words.)"Ok-I'll take you up.I took the Fs Baron to Evanston, Wy. (an airport I flew out of for real and experienced the effects of high density altitude-especially when my landing gear failed to retract on takeoff). Evanston is approx 7300 ' altitude and I set a temp of 70 f (21 C) degrees.Gave it full power and saw I was getting 20" of manifold. Took out my real Baron perf. charts and saw at that altitude I should be getting.... 20" manifold (vs. 26-27" at sea level).On the takeoff roll noticed the airspeed coming up much slower than at a sea level airport-very lethargic. Took a great deal of runway to get to 90 kts. liftoff speed-much more than at sea level-used a good deal of the runway. Then I consulted my takeoff charts and found-it was pretty accurate where this event occured.Then upped the temp to 90 F (32 C). Didn't reach 90 knts. till the end of the runway-too late for takeoff.Seems a fairly accurate simulation of high altitude/temp takeoffs.Your discussion does bring up the continual discussion of what is "serious" though. For me the entire Fs series has never been "serious" till recently as for most of the 1990's it seemed primarily for those who wanted to fly commercial jets thru ice cube looking clouds and vector terrain scenery, and thus struck me as gamelike."Serious" GA simmers like me gravitated to Pro Pilot and Fly where realistic instrumentation, clouds, aircraft models, and geographic environment was depicted. We didn't call this "eye candy" then but greater reality.I still remember a simmer at that time stating that he didn't need a "rock and soil" simulator (addressing Pro Pilot) but a "serious" simulator like MSFS. Of course now-that rock simulating is standard for all flight sims. Eye candy-or just greater reality? For me even today-flying a jet aircraft in FS which I personally never expect to fly in reality makes the sim gamelike, as I have no way to judge if it is realistic; and no training to fly it in a realistic fashion-therefore I stay away from this type of simming.I'll be the first to admit that Fsx improved the GA experience greatly for one of the first times in the Fs series I can remember-and I've been doing this since 1981. The downside of course is those whose interest was flying commercial airlines have been disapointed. I am glad for once my area of reality was addressed.. :-)If FS neglects GA in FS11 I'll probably pass on it -and stay with fsx, much like many have decided to stay with fs9 when their interests were not addressed.It would be nice if we had more options to pursue our own reality and seriousness like we did in the 1990's but that is just not the case anymore.GeofaMy blog:http://geofageofa.spaces.live.com/

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>Has MS had a tendancy to focus on the pretties>without concentrating as hard on more subtle differences that>effect flight? I rather have MS to focus on flight - 99% of the time the aircraft is actually off the ground so in my opinion any improvement in friction, wet runways, sloped runways add little to overall simulation. We still don't have viable weather like fog effects, turbulence, moisture, icing and even basic visibility to simulate typical IFR scenarios most threatening to a pilot.>Where are we with higher altitude t/offs on>baking hot days for example? Maybe you haven't noticed but this has been working correctly.Michael J.http://img142.imageshack.us/img142/9320/apollo17vf7.jpg

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>As to the OP's question "why not," that's pretty simple to>answer. ACES simply ran out of time to fully convert all the>necessary code to allow for airport runways, taxiways, and>aprons to work with the completely new, "round earth">paradigm.X-Plane tried it, but there are too many floating runways. It's now disabled by default. What it amounts too, is that too many airports will have to be programmed individually.L.Adamson

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Thinking back, I do recall that there was an add-on a few months ago that added more "realism" to aircraft braking. I wish I could remember its name, though. I do recall that it needs a registered, paid-for copy of FSUIPC to work, as FSUIPC has weather controls that are more finely tuned to aircraft performance specs than the default FSX.As a Reviewer, I have hardly any practical experience with the physics of flight, other than to have coffee (not mine) spilled on one of my better suits during a turbulent ride. My expertise is animation and, well, computerized eye candy. Still, that doesn't stop me from looking stuff up and it's easy to find experts to consult with in e-mail. ACES has divided flight-simmers into three broad categories: gamers, explorers, and hard-core users. I think that's perhaps something of an oversimplification, but it will do. On AVSIM, we see more of the latter, I think, than anything else. These hard-core users will have accurate and up-to-date flight manuals and engineering texts for their favourite aircraft. The other day, I found myself able to find the correct ILS frequency for a runway in Frankfurt. If that doesn't win some kind of bar bet in an airplanespotter pub, I don't know what would. Of course, that doesn't even hold a candle to the free-for-all of angry Interent come-uppery you can find on, say, an IL-2 forum, where you can spend weeks reading Russian technical charts and delve into the intricacies of German WWII-era superchargers. So, there are experts in everything on the Internet, whether you want to hear from them or not.Despite being really complicated, I personally feel that the goal of the aviation engineer is to create a cockpit environment where the pilot can work intuitively. Yes, there's a million little numbers on the dashboard, but there's also an implicit order to things. If the needles point to green, and the ball has blue on the top and brown on the bottom, you're probably okay. So under all of that technical sophistication, I think that most folks would be able to discover through intuition that for instance a sim aircraft's brakes are underpowered (or overpowered). Something like being able to park a 737 on an aircraft carrier would be a clue (not that I've tried that, but I do remember a thread about landing an empty 737 on a very short runway. I believe that the end consensus was that the brakes and reverse thrust worked to published specs, but that tire friction was too high. However, I believe FSX needs a high tire friction to keep the aircraft from skidding when you start the engines.) That's not taking into account real world tragedies where the pilots make errors in judgement regarding brake power. Even the experts can be fooled. This is a rambling topic, but I think it's very interesting. Jeff ShylukAssistant Managing EditorSenior Staff ReviwerAVSIM

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