Sign in to follow this  
Guest DSandberg

Realistic Simulation of Mountain Flying

Recommended Posts

I have a question about how realistic mountain flying is in Fly!II. I'm flying between Lake Country Airport (KLXV) Colorado and Aspen over a 12,000 foot pass. In real life, this area is flown by Cessna 172s and 182s, but it is quite challenging. There are a lot of downdrafts and winds along the high slopes and the 172 doesn't perform great at these high altitudes. But in Fly!2, I have no problem flying right over these high mountain passes in the Flyhawk. Here are my questions:[ul][li]Are there things I can do in Fly!2 to create a more realistic/challenging mountain flying environment?[li]Is engine performance of the Flyhawk affected by high altitude in Fly!2?[li]Do others feel that Fly!2 is too easy in this area?[li]Do other flight simulators do a better job at creating challenging mountain flying or is this a common problem for flight simulators?[/ul]I will admit, that I only have a few actual flight hours toward my PPL, so I'm not yet a professional. If others feel that Fly!2 is challenging for mountain flying, I'd love to know.Here are some pics of flying the Citabria and Flyhawk at 13,000 FT with no problems:http://home.earthlink.net/~finsdad/FlyII/p...teScenery_F.jpghttp://home.earthlink.net/~finsdad/FlyII/p...teScenery_G.jpgAnother side question: are these pics that I'm posting too large to download for other users? They're limited to 700px wide, but are almost 50K each.

Share this post


Link to post
Share on other sites
Help AVSIM continue to serve you!
Please donate today!

Dan:I assume that you have all the realism settings set to maximum.Fly! II does simulate the effects that altitude and temperature have over the engine performan. To verify this set yourself with the C172 at Lake Tahoe (for example), set the parking brake, start it and apply full throttle. Go to the weather menu, to the Other section make changes to the temperature and the atmospheric pressure confirming by pressing the OK button each time you do it. Observe how the RPM's vary. Note the maximum RPMs and you'll see they're very different to what you get at SFO, for example.As far as the slope wind, there's an entry in the Fly.ini file called ignoreSlopeWind and most likely you have set to =1. That's because in certain cases, while trying to land at an airport, you would get this updraft that wouldn't allow you to land at it, no matter how much you "sink" your nose. It seems this feature was not fully implemented but maybe it does work around mountains.Hope this answers your question... Stay away from those lenticular clouds!!!Alejandro AmigorenaCheshire, CTFly! II Beta Team MemberAthlon XP 1800ABIT KR7A-RAID768Mb RAMMSI GeForce 3 Ti 500 64MBSB Audigy GamerCH Flight Yoke USBCH Pro Pedals USB

Share this post


Link to post
Share on other sites

I was going to ask the same question- great views!Best,Joel

Share this post


Link to post
Share on other sites

This is 1/4 tile satellite scenery I'm working on for a section of the Rocky Mountains (Leadville to Aspen). I posted some screenshots of this earlier this week. I'm still working on downloading and piecing together the images and working on getting the colors right. When I'm done, I'm going to upload a Terrascene Kit that will give others the chance to reproduce the same scenery on their own machines.

Share this post


Link to post
Share on other sites

I've done a reasonable amount of real life mountain flight over the Rockies. With a Piper Archer (180HP), I made it to 12,500' msl with three of us aboard. The density altitude conditions just seemed favorable that day. I also stopped at 12,500' for oxygen requirements. Other day's, it's struggled to get to 11,500'. I figure that a 172SP, also at 180HP should do just as well. I've flown the SP versions & they're quite like the Archer performance wise at higher altitudes. Of course down drafts make all the difference on how much you want to try to clear a peak by..L.Adamson

Share this post


Link to post
Share on other sites

I get vertigo just looking at that picture...what a thrill. You're a brave man, Henri. Looks like a blast.

Share this post


Link to post
Share on other sites

Dan,You won't believe it. I have fear of heigth. I do not dare to go near the edge of a clife. However, as soon as I am strapped to my glider I don't care. It feels very safe then and depending on the weather conditions it is. Once in the air it feels as if I am riding my bicycle, only the view is a million times better.Cheers,Henrihttp://hifi.avsim.net/activesky/images/wxrebeta.jpg

Share this post


Link to post
Share on other sites

>Dan, >>You won't believe it. I have fear of heigth. I do not dare >to go near the edge of a clife. However, as soon as I am >strapped to my glider I don't care. It feels very safe then >and depending on the weather conditions it is. Once in the >air it feels as if I am riding my bicycle, only the view is >a million times better. >I'm somewhat the same way. I will look over the edge of cliff's & high buildings, but it somewhat bugs me. And you'll never see me "rock climbing" or doing tight rope acts! I even have nightmares of falling off high places. But on the other hand, I've done many spins straight towards the ground, and it doesn't get to me at all! For some reason a "wing" just offers some security.L.Adamson

Share this post


Link to post
Share on other sites

Hello Henri.Is that the old Wills Wing name on your glider? I used tohave an UP Comet 165 some years ago.Realy miss it sometimes.Converted it to a weightshift trike.French Cosmos.Then sold everything. :'( Jan

Share this post


Link to post
Share on other sites

Hi Jan,The glider on this picture was a Wills Wing Sport. After that I transfered to the HP AT 158 and now I still own a Wills Wing RamAir 154. I was heavily involved in competition for a long time. Due to lack of time I did not fly during the last two years. I just decided to sell my glider. I cannot say how much that hurts me :'(Take care,Henrihttp://hifi.avsim.net/activesky/images/wxrebeta.jpg

Share this post


Link to post
Share on other sites

I have to say that I'm fascinated by this (actually, "blown away" is probably closer to the truth). To be that far up in the heavens and basically suspended from a tiny, frail kite ... well, wow. :)I have a couple of idiotic questions (seeing as how I know next to nothing about this), if you don't mind taking the time to answer them:1) At what altitude did you initially start at?2) How long did it take for you to work your way up to 18K feet?3) How much oxygen (duration) are you able to take with you for such a flight?4) Do you wear a parachute?[table cellspacing=0 cellpadding=0][tr][td width=320]http://www.usinternet.com/users/mystic/infomsig.gif[/td][td width=170 align=center]God wants Richard Harvey to be his copilot.[/td][/tr][/table]

Share this post


Link to post
Share on other sites

Hi David,This was a truely extrordinary flight, since I had an incredible thermal. I took off at 10000 feet, which was about 2000 feet above the landing zone. After flying for a little while I sank out, but caught a thermal about 200 feet above the valley floor. This thermal took me up some 12000 feet, where most of the climb (during 5 minutes if I remember correctly) I had an average climb rate of 1400 feet per minute. A friend of mine was keeping track of my altitude using a stop watch; my variometer at that time only went to 1000 feet per minute. You can calculate now how high I finally got ;-) . I stayed at that altitude for 15 minutes perhaps, certainly suffering from some hypoxia, since I did not have additional oxygen. However, I lived at over 5000 feet at that time (Boulder, CO) and camped every weekend at 10,000 feet. In total I was at or above 18,000 feet during 1.5 hours, during which I could make a nice cross country flight. And finally, yes, I do have an emergency parachute. Every hang glider pilot does. BTW, a hang glider can withstand the same forces as a normal plane. We are just a lot lighter.Cheers,Henrihttp://hifi.avsim.net/activesky/images/wxrebeta.jpg

Share this post


Link to post
Share on other sites

Overall I think Fly does a pretty good job of modelling the atmospheric effects on the flight model. One time I had a repeatable problem when I loaded a particular metar cycle file. As soon as I flew into an area between OKC and DFW all the A/C temp readings maxed out and the A/C would loose lift and spiral into the ground. At first I couldn't figure out what was happening with the sim. I finally determined the metar cycle was reporting from one particular station an ambient temperature around 400 degrees!

Share this post


Link to post
Share on other sites

That's been known to happen when a PK WND element is a part of the METAR report's comments section. If you use InfoMETAR to preprocess METARs before loading them into Fly!, you won't run into that problem anymore.Of course it's always possible it was just a different type of random METAR error, but by far the most common cause of wildly off temperature/dewpoint after loading METARs is the presence of a PK WND entry.[table cellspacing=0 cellpadding=0][tr][td width=320]http://www.usinternet.com/users/mystic/infomsig.gif[/td][td width=170 align=center]God wants Richard Harvey to be his copilot.[/td][/tr][/table]

Share this post


Link to post
Share on other sites

This is really a great discussion. Reading about hangliding is fascinating too. I'm amazed at all the other things Fly!2 community members are involved in.David...regarding Fly!2's weather simulation, can I assume that depending on the METAR information I download with InfoMETAR, Fly!2 may simulate conditions where my 172SP will have a harder time around 12-14K feet than at lower elevations? Or is it not that granular?

Share this post


Link to post
Share on other sites

I agree about the hangliding ... I'm sure it's safer than the idea seems, but I'm still amazed. The experience of hanging that high above the mountains, up in the rarified air, with only that tiny non-motorized wing to keep you there ... well, it sounds like an experience one would remember for a lifetime, at the very least. Just looking at Henri's picture confirms that much.There are two answers to your weather question. First, Fly II ought to be doing a reasonable job of simulating typical adiabatic lapse rates for temperature and dewpoint (and hence density altitude) as altitude increases, with associated changes in engine and wing performance. This should be true regardless of how the weather was generated (METARs, global weather setting, or whatever). How accurate the flight modeling is with regards to simulating the effect of those changes I can't say ... there are others better qualified to express an opinion about that.As far as specific layer information with METAR weather, this really doesn't exist as a part of METAR reports (outside of visible cloud layer information). METARs are surface observations only ... no balloon soundings or anything similar that would include information about temperature, dewpoint, or wind changes with altitude is present in METARs. There are different types of weather reports that include such information (FAs in particular), but those are not supported by Fly II (or any other sim that I'm aware of, for that matter).[table cellspacing=0 cellpadding=0][tr][td width=320]http://www.usinternet.com/users/mystic/infomsig.gif[/td][td width=170 align=center]God wants Richard Harvey to be his copilot.[/td][/tr][/table]

Share this post


Link to post
Share on other sites

David,This was definitely before I started using Infometar to process my metar files. I have never run into this type of problem again but it sure added a new element! First I noticed all the temp readings climbing to their max reading and then no more lift. Talk about an unexpected, unrecoverable in-flight emergency! BTW, what is a PK WND element?

Share this post


Link to post
Share on other sites

PK WND is a METAR comment element that indicates the highest winds recorded at the location during the cycle period, as you might expect. It only commonly shows up during windy events (I recall that we first encountered this problem with Fly! 1.0 when people tried to go flying in weather from an East Coast hurricane.)[table cellspacing=0 cellpadding=0][tr][td width=320]http://www.usinternet.com/users/mystic/infomsig.gif[/td][td width=170 align=center]God wants Richard Harvey to be his copilot.[/td][/tr][/table]

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this