Modify drag

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zuentec
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Joined: 23 May 2019, 13:40

Re: Modify drag

Post by zuentec »

Oracle427 wrote: 24 May 2019, 17:40 I saw in the first post that the airfield in EDMJ. Found some videos on youtube of landings at the field. I see there are no obstructions or terrain in the approach and the technique seems to be to come in low and flat and touch down as close as possible to the threshold. In this case, I can see that the landing performance is well within the limits of the POH provided that the pilot is on their game. It definitely is not going to be the easiest field to land at!

Unfortunately, my FSX places a zillion trees about 10 feet from the threshold, so I end up having to ignore and fly through them to make the landing. :)

Still, the next time I fly the 172, I'll take notes about performance with flaps fully extended, straight and level flight at constant airspeed and power and see how many RPMs I am turning at 65KIAS. I am going to guess very close to 2400 RPM.
Today I have tried a different approach in the real C172 (D-EZTE): Very slow at top of descent (63 KIAS ) at 2500 ft AGL / -600 ft/min > Full flaps. In this condition the real one exactly behaves like the A2A baby...

Now I see how difficult it must be to design a virtual aircraft and how impossible it is to match in every possible case. But as a demanding customer I didn't find a better virtual aircraft. Thank you all for your ideas :-)

And all the best from the Alps.

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Oracle427
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Re: Modify drag

Post by Oracle427 »

Zuentec,

Great to hear. If there is conflicting data, do share, all I was asking is to structure the test to make it reproducible both in the real aircraft and the sim. That looks like a really nice field!

Nick,

I installed Lumberjack, but haven't seen a difference yet, I'll have to play with it when I get a chance.

Dave
Flight Simmer since 1983. PP ASEL IR Tailwheel
N28021 1979 Super Viking 17-30A

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iefbr14
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Joined: 16 Oct 2013, 14:44

Re: Modify drag

Post by iefbr14 »

zuentec wrote: 23 May 2019, 16:08 This is also strange: In real life nose down is the typical answer of a C172 during full flaps extension. In sim the effect doesn't feel realistic to me...
This is the Flight Academy Board here, where you get some flying tips :roll: Probably, in the technical forum, one answer for a technical reason might be, trying to switch off thermic effects in your FS. I've found this when I unsuccessfully tried to land at EDHE using Aerosoft German Airfield Nordlichter Scenery, on a 1100m grass strip, with full flaps and idle engine.

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zuentec
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Re: Modify drag

Post by zuentec »

[/quote]
This is the Flight Academy Board here, where you get some flying tips :roll: Probably, in the technical forum, one answer for a technical reason might be, trying to switch off thermic effects in your FS. I've found this when I unsuccessfully tried to land at EDHE using Aerosoft German Airfield Nordlichter Scenery, on a 1100m grass strip, with full flaps and idle engine.
[/quote]

You are the man! Indeed "Thermal Effects" is something that makes it feel wired. Switching it off was not in my list of troubleshooting actions. Thanks a lot!

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iefbr14
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Re: Modify drag

Post by iefbr14 »

[/quote]
... trying to switch off thermic effects in your FS. I've found this when I unsuccessfully tried to land at EDHE using Aerosoft German Airfield Nordlichter Scenery, on a 1100m grass strip, with full flaps and idle engine.
[/quote]

Just a short update, it wasn't the Aerosoft Nordlichter Scenery, it is ORBX Germany North, which is producing too much thermal upwind here. For example, with the A2A 172 I was able climbing over the field (EDHE) from 300ft to over 900ft with idle engines :shock:

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AKar
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Re: Modify drag

Post by AKar »

Good catch. At least some of the thermals in FSX/P3D appear to be rather static in placement, residing over certain spots over ground. I am not sure what actually puts them in place: are they directly placed within the scenery or are they dynamically created based on land type and some other factors by the weather engine.

It is unfortunate that the modeling of the thermals themselves has not really gotten any better even if some aspects of the weather simulation have. The thermals still appear as excessively vast areas of steady updraft, giving what appears to be exactly constant positive vertical wind component within their areas of influence.

-Esa

Hook
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Re: Modify drag

Post by Hook »

The file that defines thermals is the following: C:\ProgramData\Lockheed Martin\Prepar3D v4\ThermalDescriptions.xml and it's probably worth a look to see how it works.

If you want to get rid of these in P3D, you can't just delete the file. You have to blank it out by setting a single null thermal (the first entry). If I remember right, in FSX you could simply delete the file but it's been a while.

Hook

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iefbr14
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Re: Modify drag

Post by iefbr14 »

Hook wrote: 22 Jan 2020, 09:11 The file that defines thermals is the following: C:\ProgramData\Lockheed Martin\Prepar3D v4\ThermalDescriptions.xml and it's probably worth a look to see how it works.
Thank you for the tip, I'll give it a try.

Andreas

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