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Modified cfg and air for DG808S


bruin

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* airbrakes/spoilers - also now adjusted to a more realistic performance. Warning.. they're not speed-limiting in a vertical dive any more!

Hm, is this correct? Afaik, glider airbrakes should be sufficient not to exceed Vne at least. Once I tested a real LS4 which didn't go beyond 160 km/h in vertical dive. Though, here spoilers are well known for their effectivity.

regards,

Peter

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Afaik, glider airbrakes should be sufficient not to exceed Vne at least

LOL no offence but since about 1988 this went *right* out the window, when the wing sections became a lot thinner, probably starting with the ASW24 (my glider) and the LS7. There's been some effort with 'triple-paddle' airbrakes to get more surface area out of the airbrakes when extended - e.g. the ASW27 - but even then they're not speed-limiting because the wing is soooo thin... for what it's worth the DG808S actually only has double-paddle airbrakes. Even though all manufacturers advertise their airbrakes as 'especially effective' somehow (including the DG808S) this is relative to how bad they could have been if they weren't somehow special. I would guess most current airbrakes would be speed-limiting in maybe a 45-degree dive, but the standard I think you're referring to is speed-limiting in any circumstance, e.g. including vertical.

An impact has been on cloud-flying, because in the good-old-days you could enter a cloud and know that worst-case you could open the airbrakes and spin out without the wings coming off.

Ian

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Brief update - we've reached a 'release candidate' for the 'virtualsoaring DG808S' and Bert and Peter are hopefully taking a peek to check we haven't made a hash of it. New polar, airbrake and flap aerodynamics. New instruments. Remake of 'Mifflin Day 1' mission with better weather using this aircraft.

Ian

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I am so amazed and awestruck by what you guys have achieved in a week or so; as far as I am concerned you guys are the "brains trust" and are greatly facilitating the future of virtual soaring.

What is the aerodynamic effect of changes proposed for the flap settings?

fantastic effort

Hodge

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Thanks Hodge - you'll have to download the 'SOAR DG808S' when it's posted and make up your own mind as the aerodynamics changes are both subtle and not-so-subtle. Bert and I have compared notes on what we have as 'release candidate 1' which includes instruments and an update of Mifflin Day 1 using the new plane and have agreed that aerodynamically we're completed. Bert mentioned a couple of tweaks to the instruments/mission and I'll do those so we have a 'release candidate 2' tonight, and assuming they're ok we'll be good to go.

My 2-cents worth:

We know from using a real-time L/D gauge we've got the *polar* a lot more accurate than it was. This is true at high speed, where the stock FSX DG808S is dropping like a brick at 100 knots+ and we've modified the air parameters to get this quite accurate. Also you may not have known the FSX DG808S was capable of truly spectacular performance in negative flap at very low speed, which was very wrong but not many pilots actually flew in that regime, although it does explain a miraculous scraping final glide I made to get back on a Mifflin mission.

The airbrakes are also a lot more accurate, where the FSX DG808S would almost stop in mid-air. So the bad news is you have weaker airbrakes, but the good news is the airspeed doesn't drop dramatically as you open the airbrakes on the final approach... we've calibrated the airbrakes to give you an L/D of about 6..7 at 60 knots, which is fairly authentic. If you want to come down faster, put the nose down and burn energy.

The new flap performance is at least a reasonable approximation of what happens in the real glider, i.e. positive flap is better at low speed and negative better for high speed which is a bigger improvement than you might expect on the FSX DG808S. I would have liked to have made the flap difference more extreme (big positive flap should really kill the glide performance at high speed) but had to keep the differences more limited to avoid other side effects on the glider performance.

The stall speed is higher in negative flap, or with full ballast, or with the airbrakes open. Pilots of the FSX DG808S may not be used to any of these, but if you land with no ballast and full positive flap it's as easy as it ever was.

In general the SOAR DG808S now feels a bit of a racehorse compared to FSX DG, including being more responsive to turbulence and a bit more sensitive in pitch, and this and the reduced airbrake performance mean you have to take more care on the landing. But I wouldn't want to overstate it - after flying the SOAR DG808S for a while I got used to it and you're basically back in the sim you're familiar with. Reading my post myself I'm at risk of over-dramatising a basic airfile update, but it was surprising (to me) how many parameters there were to adjust, how they significantly altered the feel of the glider in the sim, and the amount a single parameter would affect many different aspects of the glider behaviour.

But the changes will appeal to some while others may well not like them.

Ian

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Ian,

Check your Email.

Well folks,

I tested the RC2 tonight and found only a few minor things concerning the installation proces left to do. So if Ian can find the time to do these last fixes the release should be out within a day or two.

Hé, but don't kill us and be patient if it takes longer, it's freeware you know :winks:

Bert

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I took an effort to evaluate yesterday evening, but sadly had to find out, that I had a hard disk corruption, which led to CTD of FSX.

I'm currently restoring a backup and think that I can do some testing this evening.

regards,

Peter

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Hi Peter - fyi from RC2 we just had a couple of issues, neither related to the aerodynamics which is probably the bit people care about...

If you have vista it would be helpful to see if there's a workaround for IE7 giving an activex warning on *any* html file held locally on the hard drive. This (or maybe the Vista firewall) is causing FSX to get a bit bent out of shape with the mission HTML briefing, but it's ok on XP. Bert has confirmed you can right-click the htm files in Windows Explorer and select 'unblock' but it would be nice to know if there's a simpler way for the install. As far as I can tell this would affect *any* mission so I'm a bit puzzled what any else has done about it. There's plenty of omment on the web about the awkwardness of using IE7 for local files but not with FSX... maybe this is actually Vista firewall. NB the html files are 100% plain text so activex has nothing to do with it...

Ian

Ian

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Ian/Peter,

Let's not make a big deal out of the ActiveX issue. I am convinced the html's are oké, because they are the same as in the original Mifflin day1 Mission, and in that mission the briefing html's show as they should.

The "problem" is on my side of the line, my computer recognizes possible security-risks and therefore blocks automated loading of the briefing html's (i.e. I received some html's from another computer (virus-risk1). In one of the html's there is a commandline, saying to load three other html's (virus-risk2). It is just a on-time action to tell Vista that it's oke to do what the html commands, by lowering the security-level in the property. We already have made a note of how to act when this might happen in the readme.

Bert

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Given that the air brakes will be less effective now, is there any noticeable aerodynamic effect on the DG808 when the Landing Gear is lowered or is this inconsequential?

Hodge

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Given that the air brakes will be less effective now, is there any noticeable aerodynamic effect on the DG808 when the Landing Gear is lowered or is this inconsequential?

Hodge

Lol great question - Bert and I have discussed exactly this item. As things stand the drag due to the mainwheel being lowered is actually higher than in a real glider. So far (we're on a 'release candidate') we have *not* reduced the drag of the wheel, so landings are just a tad easier. The 'wheel-down drag' really is a single parameter in the air file with no collateral impact during wheel-up so it could be a candidate to change if we wanted to delay things over it.

Ian

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Ian,

I think the problem is we don't really know how much drag the wheel-down causes in R/L. I guess there should be some but I didn't find any hard statistics about it. And in real life there is also an extra amount of noise when leaving the wheel down during flight.

Knowing we can't simulate that extra amount of noise, there should be a noticable loss of aero-dynamic effectiveness, to get the simpilot's attention to do the wheel check.

This and the fact that wheel down as it is now in the Release Candidate helps the DG808S to simulate more realistic finals/landings, my suggestion is to leave the wheel down drag the way it is.

But hé, it's just another opinion of course.

Bert

PS And no, we can't simulate drag or other realistic behaviour when the simmer opens the canopy while flying :winks:

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Got it Peter. To keep the 'paying public' in the loop we're now circulating in the project team (me, Peter, Bert) 'release candidate 4' which *could* be the final release. In any case I really want to get the final version done today or tomorrow because I goof off to the USA for two weeks the day after.

Peter has added some improvements to the aerodynamics in the area of 'yaw' behaviour, and I've possibly delayed things by tweaking the drag of the gear-down mainwheel (against all good advice :whistling: ) to see if we like it or not. Otherwise we've just tidied the install package since the last version. Whether we keep the gear drag change or not, either way we should be able to ship the 'production' version today or tomorrow.

It'll be posted as freeware on this site.

Ian

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Project completed !

Don,

PM sent with a link to the new package plus some suitable text, and a request for a news item and an entry in the downloads section.

Bert and Peter both have a copy of the zip in their email - I'm now off on vacation until Oct 31st and will be able to see the internet but not FSX...

Ian

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Here is some official information about air-files:

http://msdn.microsoft.com/en-us/library/cc526961.aspx

regards,

Peter

And here about aircraft.cfg files: http://msdn.microsoft.com/en-us/library/cc526949.aspx

BTW Peter: Do you have the "Flight Model SDK" in your SDK-package? I have FSX De Luxe and installed (and did a reïnstall yeterday) the SDK that belongs to SP2,

but the folder "SimObject Creation Kit/Flight Model SDK/Samples" mentioned in the article you linked still is not there on my computer.

Bert

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Sadly, not. The Airfile SDK is currently only with ESP. Still the information in the samples give some clues also for other tools. Hopefully, it will be released still.

At this time it seems, that a many existing airfiles are a mixture of several FS airfile generations, and possible the simulator engine chooses from the existing records the most modern ones. It seems that the CRJ700 is an all new FSX airfile, while C172 is not.

The FSX airfile appears to have much less parameters than previous ones, and more information is contained in the aircraft.cfg. Still the information is heavily incomplete and vague (as ususal), for example wing area is considered from the flight file, but elevator area is not, apparently (btw, the 808 elevator in the cfg gile is ridiculously large, 16sqft, compared to the horizontal tail, which is 12 sqft). Nevertheless it doesn't have an effect.

regards,

Peter

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  • 3 weeks later...

Hi Ian

I have been holding off downloading the new DG just in case some additional wrinkles were still being ironed out. Would you say it is all go at this stage?

Jeff

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  • 2 weeks later...

SOAR DG808_V2 is downloadable in the SOAR downloads section. :yahoo:

Note for those who have installed SOAR DG808S V1:

The install proces of V2, as described in the readme. It will:

- bring the default FSX DG-808S back to default;

- disable SOAR DG808S V1;

- show SOAR V2 in the aircraft select list as a variation of the default DG-808S.

Bert

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