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Diamond Da-40 - MSFS vs. real world?


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I have been flying the Da-40 several times in MSFS. A nice-looking plane and it flies very nice. Has a similar instrument layout as the Cessna 172 (with G1000 of course). I looked at references to the Da-40 in the real world. Specs say that a cruise of 150 or so is normal specification. On MSFS the speed display goes to yellow at 130. And full power at level flight does not go faster than 130. Did MS downgrade this airplane? Or is it just not accurate.
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I have been flying the Da-40 several times in MSFS. A nice-looking plane and it flies very nice. Has a similar instrument layout as the Cessna 172 (with G1000 of course). I looked at references to the Da-40 in the real world. Specs say that a cruise of 150 or so is normal specification. On MSFS the speed display goes to yellow at 130. And full power at level flight does not go faster than 130. Did MS downgrade this airplane? Or is it just not accurate.

 

It's neither downgraded nor inaccurate, from what I can tell.

 

I just looked up a POH for the DA-40 from 2010. There, the maximum structural cruising speed is listed as 129 knots, meaning this is the maximum recommended speed in perfectly smooth air. This number is consistent with the speed display as you describe it. The yellow portion of the display is telling you that it may be permissible to reach speeds in that portion, in perfectly smooth air, but do so with caution.

 

I don't know what your source is for "specs" saying that cruise of 150 is normal. That doesn't sound right per the POH. Anyway, if you're cruising at 129 and lower the nose, you could easily reach 150, and this is where the manufacturer is warning you: go ahead and hit 150 if you like, in perfect conditions, but be careful.

 

In the real world, the consequence of exceeding speed barriers is the breaking apart of your airplane in mid-air. This is terrifying stuff!

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130 knots is 150 MPH -- that might be the difference.

 

Ah, perhaps that explains it. I get confused why aircraft use knots. Why do we need yet another speed or distance measurement. Is this tied back to ships somehow? I guess if it confuses me too much I could switch to metric. There probably is a way to switch to KPH in the controls somewhere.

 

Pat

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Multiply knots by 1.15 to get mph, or divide mph by 1.15 to get knots. For me it's easy to recall that 100 kts is 115 mph, or mph is 15 more per 100. And yes, the measurement system came from the nautical world, and even has a logical basis for vehicles going long haul, since a nautical mile started out as one minute of latitude (1/60º), making navigation quite a bit easier on charts marked with lat/long.

 

Here's a brief entry from Wikipedia:

 

A nautical mile is a unit of measurement used in air, marine, and space navigation, and for the definition of territorial waters. Historically, it was defined as one minute (1 / 60 of a degree) of latitude along any line of longitude.Today the international nautical mile is defined as exactly 1852 metres (6076 ft; 1.151 mi). The derived unit of speed is the knot, one nautical mile per hour.

 

Aircraft in the U.S. used to use MPH, but over the last part of the 20th century, the industry started to do things the same way as much of the rest of the world, thus knots (nautical miles per hour) and METARS (used to be sequence reports, which I liked better, but they didn't ask me), a bit of a change in flight plan forms, and some other minor odds and ends.

 

Larry N.

As Skylab would say:

Remember: Aviation is NOT an exact Science!

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Isn't the issue that the specs are KTAS and the gauge is showing KIAS?

 

Duh.. :o

 

It certainly is a possible answer, depending on the altitude and temperature. Under some conditions (low altitude, low temp) the two would be close, while at higher altitudes in summer temps it could easily be the difference. In FSX and P3D it's easy enough to change the gauge to read TAS briefly to check that -- don't know if 2020 does that or not. Or, if Pat (OP) specifies the altitude, barometer (altimeter setting) and altitude we could easily calculate that.

 

So that brings up the question for Pat -- are you familiar with the difference between indicated and true airspeed? With the difference in performance and instrument readings that the thinner air of higher altitudes and higher temperatures can cause? In short, all else being equal, the higher the altitude the lower the airspeed instrument will read at a given True airspeed.

 

Larry N.

As Skylab would say:

Remember: Aviation is NOT an exact Science!

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Duh.. :o

 

It certainly is a possible answer, depending on the altitude and temperature. Under some conditions (low altitude, low temp) the two would be close, while at higher altitudes in summer temps it could easily be the difference. In FSX and P3D it's easy enough to change the gauge to read TAS briefly to check that -- don't know if 2020 does that or not. Or, if Pat (OP) specifies the altitude, barometer (altimeter setting) and altitude we could easily calculate that.

 

So that brings up the question for Pat -- are you familiar with the difference between indicated and true airspeed? With the difference in performance and instrument readings that the thinner air of higher altitudes and higher temperatures can cause? In short, all else being equal, the higher the altitude the lower the airspeed instrument will read at a given True airspeed.

 

I took the DA40 up for a spin today and I think it's just Indicated vs True Airspeed difference. I went to 11,500 feet, temp 1C, barometer 29.97. KIAS=119 KTS, KTAS=142KTS.

 

Pat, if you look at the bottom of the Airspeed tape you'll see the TAS displayed.

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I took the DA40 up for a spin today and I think it's just Indicated vs True Airspeed difference. I went to 11,500 feet, temp 1C, barometer 29.97. KIAS=119 KTS, KTAS=142KTS.

 

Pat, if you look at the bottom of the Airspeed tape you'll see the TAS displayed.

 

Under those conditions there certainly would be a huge difference. At 1,000 MSL and 60º F the figures would be MUCH closer; Thanks for getting actual numbers. Not having FS2020 I couldn't check those.

 

Larry N.

As Skylab would say:

Remember: Aviation is NOT an exact Science!

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Under those conditions there certainly would be a huge difference. At 1,000 MSL and 60º F the figures would be MUCH closer; Thanks for getting actual numbers. Not having FS2020 I couldn't check those.

 

Expectation is as much based on expectation as reality.

I never expect a DA40 to achieve 150 KIAS, except in a dive. The TDi is a modest-powered aircraft!

The NG is the one, I believe, rendered here and has the even more-modest AE300 diesel engine with just 168 hp.

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I'm back on the thread. Was not monitoring things the last couple of days. The confusion that I had was that I was seeing the speed quoted in MPH and then was looking at the knots speed (KIAS ?) as indicated on the speed display. I think that explains the whole difference for my confusion.

I then moaned a bit about trying to understand speed in knots and nautical miles. I will just have to get used to that one, it seems. So it is a global default to have the speed in KIAS on the speedo? i played with changing default units to metric in MSFS. This changed the distance measurements to Km but did not change the instruments.

 

>>>I never expect a DA40 to achieve 150 KIAS, except in a dive. The TDi is a modest-powered aircraft!

The NG is the one, I believe, rendered here and has the even more-modest AE300 diesel engine with just 168 hp.

Yes the model in the standard version of MSFS in the NG with the turbo-diesel. It does not have a mixture control (fuel-injected ?) so one just sets the throttle. I read a review about the plane IRL, they pointed out that the turbo-diesel maintains horsepower at altitude up to like 10K feet. So it may match or pass the gas engine in performance as one goes up. Not sure if this is modeled in MSFS. My flying is not detailed enough to give an answer to that. I did play around with some flights in western Colorado, flying out of Telluride - KTEX. The performance climbing from 10k to 12K in the DA40 was definitely better than the Cessna 172. The Cessna was struggling at that altitude. I had set the climb using VS with the autopilot and the climb rate was too much. I noticed it when the stall warnings started sounding. I could only climb at 300 or 400 fpm.

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So it is a global default to have the speed in KIAS on the speedo?

Yes, except on many older (probably pre-1980) aircraft, where it used to almost always be MPH (in the U.S. at least). There was a period when MPH was the outside and larger scale on the ASI and knots was on the inside in smaller type. There was also the dual scale but with knots on the outside edge. Today it's generally just knots.

 

I did play around with some flights in western Colorado, flying out of Telluride - KTEX. The performance climbing from 10k to 12K in the DA40 was definitely better than the Cessna 172. The Cessna was struggling at that altitude. I had set the climb using VS with the autopilot and the climb rate was too much. I noticed it when the stall warnings started sounding. I could only climb at 300 or 400 fpm.

 

Those figures sound close to the real world -- turbo charging makes a BIG difference up there. On a hot day you wouldn't have gotten 300 fpm, if it would climb at all. At those kinds of altitudes the C-172 becomes a 2 place aircraft (performance and safety wise), and when temps at those altitudes get up to 70º-80º and more the C-172 probably should remain on the ground. Even at 45º you probably shouldn't have more than two people on board, as performance will be lackluster, to be kind. In fact at 5000 feet on a 90º day it is still only a two place aircraft.

 

Larry N.

As Skylab would say:

Remember: Aviation is NOT an exact Science!

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  • 1 year later...

Dear all,

 

My 2 cents about this matter and the initial topic.

When I compare the DA40 TDI on MSFS and the same in real life, I must say it's just arcade.

I don't feel the same at all flying it on the SIM compared to real life.

Among other things:

- engine settings are not accurate, unable to deliver 100% load at FL85 while the real one does

- the plane tends to turn while in cruise, but the real one is very stable and remains levelled.

- 2300rpm at 73% load at FL85 is an invention of Microsoft, would never happen in real life...

- you hardly reach 120kt full throttle while even the smallest real life engine (thielert 135hp) delivers 130kt at 75% load...

 

So for having flown a lot of hours on DA40 in real life, believe me, it's not realistic...

MSFS has never been developed for realism, it's an arcade game designed for Xbox and we have to accept it.

If we want something professional we take P3D.

 

Jo

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