DV20 flaps create insufficient drag

Actual DV20 models were unusable since last November when CG went too far away. Since then we’re forced to use the original DV20 that was introduced with the game. More or less it seemed to be correct from many aspects.
Now, that CG setting makes it possible for us to use the actual DV20 model I’ve discovered that flaps are very far from their real-world performance, even Landing flaps generate less drag than T/O flaps IRL. Is it possible that the previous flaps issue was not corrected on the DV20?

It happens every time and seems to be a general issue happening with others too.
Just try to descend, add max flaps and see that IAS speed change with level AC only changes very slowly (real world the slowing effect is immediate and much stronger), during descent the plane gains speed if we try the same approach degree like IRL where it should maintain or loose speed on Landing flaps and flare takes a lot of runway length. Even on full flaps and adding 100% weariness to the plane, it hardly slows down to stall speed.

I’ve submitted it to Zendesk too!

it could be the explanation. I just know that even with the last update, the center of gravity is in range, but the flight model is not realistic at all. I fly this plane in real life, and when I fly the same airport circuit the plane just keep gliding over the runway in msfs. I cant land with the same reference I am use to. While when i fly the d40 the flight model is close from what I fly in real life. I just gave up flying the dv20 in msf20 unfortunatly.

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Same here, maxing out the “parasite drag” and use Landing flaps much earlier I used to I can recreate a traffic pattern that resembles the real one but it’s still not that easy.

After a few weeks lockdown IRL pilot training became available again.
The wind was pretty gusty but got a chance to at least estimate the vario values in a DA20-100 with MTOW.

  1. With T/O flaps keeping speed around KIAS 70 I got around 400-600fpm descent rate.
  2. With Landing flaps keeping speed around KIAS 70 I got around 700-1000fpm descent rate.
    During my last sim trainings I’ve noticed the situation to be a bit better, it started to better resemble my “old” memories how the DV20 should descent. Is it possible there was a “silent” update on DV20 lately?
    I’ll compare these IRL values to what I’ve experienced in the sim but AFAIK they pretty much similar.
    Remember: As I’m flying old planes IRL I also put “drag” settings to 80-90% in game. That gives me similar airspeeds with the set performance % (of course performance setting itself is different for the same power on an old, carb DA20-100 or DV20-100 then an injected DV20-E) so I compare my IRL experiences to such customized sim plane.
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Did some solo traffic patterns in calm(er) winds with a DA20-100 so I had the chance to test the different flaps settings again. Definitely the flaps create a lot more drag IRL. With landing flaps I’m able to descend with 70kt IAS on a lot steeper and flare takes a lot less time (and distance).
Since I need a lot of attention to fly the plane itself alone I cannot give exact numbers now but I’ll check my GPS log and add some numbers here to show the IRL capabilities.
Edit: I’ve analyzed my logs. Traffic pattern is at 1200ft AAL. I usually descend with the following parameters: 500fpm, 70kias, glide path: 6-8%. That’s an average, around 50% of the descent is done with T/O flaps and the remaining 50% is with Landing flaps. In some cases I saw more than 1000fpm still maintaining 70kts. I’ve not recorded pitch degree bit the Garmin G5 started to show one “inverted V” on the screen sometimes :slight_smile: so I expect it was deep enough…

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I also think that flaps in LDG give too little drag. Is there a chance to modify anything in the config files to increase it?

Unfortunately no. I’d have done it already but as it’s not a standard plane the files are encrypted.
According to my new test IRL yesterday (10 traffic pattern circles in relative low wind) with LDG flaps the DV20 is capable to sink around 15-20degrees pitch (depending on the engine power) with 70KIAS.
I’ll also check it in sim to but as I remember you cannot pitch down more than 5-10% even with LDG flaps or the plane will accelerate a lot above 70kias. I’ll add my in-game experience when I’ve done the testing.

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Checked the status after the latest update. It’s a pity that even flaps rework is mentioned, DV20 flaps seem to be unchanged, they’re still inefficient. Still cannot go below -10 degrees of pitch to maintain 70kias while IRL it can be maintained close to -20 degrees.

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I don’t think that this is only a flaps problem on any of the Diamond aircraft in MSFS.
They are all using a NACA2412 like airfoils instead of the correct high lift Wortmann FX ones.
This results in a noticeable too high pitch attitude at basically all speeds and configurations.

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Hm… Interesting observation. How could you find it out? Were you checking the standard Diamonds config files?
I recall DA62 was a bit harsh on landing (needed higher speeds during flare not to fall down quickly) but for me DV20 flares too long. That’s why I assumed flaps drag is misconfigured. The other facts (like incorrect pitch values) support the incorrect airfoil adaptation but the flare seems to take too long and it was much better before the first changes to flaps effects have been introduced during the winter.

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Just by comparing the pitch attitudes e.g. during climb and cruise with my own data and youtube videos.

I am facing same issue, never flown this bird in RL but from experience of other planes I can say it could not be anywhere near RL counterpart, plus I have observed weird RPM behaviour on landing, Max or 2260 RPM doesn’t go down even at Idle or power 10 in hg, all in all this plane is not landing friendly in MSFS, other minor niggles are traction on ground and rudder on rolling

Interesting !! what is your power settings?

Generally between 10-15 but if I need steeper dive I sometimes put it on idle. I’m aiming to maintain the speed and the angle visually with Fpm between 300-500.
When I’m “falling” with 1000fpm that means I have not counted something well. :slight_smile:
In such cases I’m on idle usually.

Chiming in on the wrong drag on the DV20 in the sim. I fly this aircraft in real life and both T/O flaps and full flaps has the same landing characteristic as landing flapless. The aircraft just glide during the flare phase like there’s no flaps.

Another wrong evidence is that with T/O flaps + carb heat, you’d need ~25" manifold pressure to maintain level flight at 70 knots (downwind). In the sim I only need ~15".

Trying to use the DA20 in MSFS for practice is not feasible.

Any news on anyone building a mod for the default aircraft?
I tried changing the drag value in the DA20 config files but I believe MSFS is not picking up on them as I don’t feel any change.

@MrTommymxr is a “Diamond modder”, created already very nice DA62 and DA40 mods. He promised to have a look on DV20 too if we can provide RL data about the behaviour of the plane.
Unfortunately in the last weeks I didn’t had the chance to fly in a DA/DV20 but if you have some data, like RL pitch and vertical speed values with fixed IAS (70kts for example) on TO/LDG flaps using different manifold pressure or you can obtain those earlier than me they’d be very useful.
Since the models I fly have the weaker engines than sim version my MP values wouldn’t be too useful anyway but the free glide datas might still prove useful for better flight characteristics.

I suspect its a problem with propeller thrust and not flap drag. The flap drag in the file is reasonable and with a 1.4 scalar on it, is probably too high. I will look into it more and post a solution here, if I am able to fix it.

I wonder if you have had the chance to look into it? I would love to use the DV20 as a training plane for landing. Thanks!

Hello, I was a sales pilot at HOAC 1992, have a lot of hours on the DV20. The flight model in MSFS is bad, bad, bad. Flaps, prop rpm, manifold-speed/sinkrate is way off. It’s now 2 years later and this has not been fixed.
Is there an easy way to tune these issues in the developer mode?

Kind regards
Andreas OE-AKL

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Another major problem is that all the Diamonds in MSFS are using the standard NACA 2412 or Clark Y, instead of the correct Wortmann FX airfoil, which means that the lift/drag relationship is way off, pitch attitudes, Vx, Vy etc.
I’ve reported all these bugs, including the RPM problems directly to Asobo already during alpha testing. These bugs were acknowledged by Asobo, but they were never fixed.

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