Flying Magazine Review of DA40 NG

Any DA40 related topics

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Don
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Re: Flying Magazine Review of DA40 NG

Post by Don »

It is hard for me to fathom that the increased gross weight of 242 pounds over the XLT, plus approximately four or five less square feet of wing surface area would cause such a delta, (15 knots) in stall speed when flaps are in the fully up position. Would just that amount of difference with the wing loading cause such a large amount of stall speed change?
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Rich
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Re: Flying Magazine Review of DA40 NG

Post by Rich »

Don wrote:It is hard for me to fathom that the increased gross weight of 242 pounds over the XLT, plus approximately four or five less square feet of wing surface area would cause such a delta in stall speed when flaps are in the fully up position. Would just that amount of difference with the wing loading cause such a large amount of stall speed change?
It's also a function of where the CG is. Remember, forward CG produces higher stall speeds and that is where the tests are performed.

Example:
DA40-180's at 2646 lb has a forward CG limit of 97.6 in., clean stall speed 53 KIAS
The NG at 2646 lb has a forward CG limit at about 95.9 in., clean stall speed 64 KIAS

And remember that the wing doesn't just support the weight of the airplane, it also has to counter the downforce of the elevator. The NG has 374 lb-ft. more downward moment at this particular CG loading than the -180's which must be countered by the elevator.
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
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Keith M
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Re: Flying Magazine Review of DA40 NG

Post by Keith M »

It's equally hard for me to fathom why Diamond would risk their reputation for building safe aircraft by letting the NG get to market like that. The consequence is a lot of extra energy to bleed off if the engine quits, so they must be keeping their fingers crossed that the Austro really is more reliable than the CD-155.
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Don
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Re: Flying Magazine Review of DA40 NG

Post by Don »

Rich wrote:
Don wrote:It is hard for me to fathom that the increased gross weight of 242 pounds over the XLT, plus approximately four or five less square feet of wing surface area would cause such a delta in stall speed when flaps are in the fully up position. Would just that amount of difference with the wing loading cause such a large amount of stall speed change?
It's also a function of where the CG is. Remember, forward CG produces higher stall speeds and that is where the tests are performed.

Example:
DA40-180's at 2646 lb has a forward CG limit of 97.6 in., clean stall speed 53 KIAS
The NG at 2646 lb has a forward CG limit at about 95.9 in., clean stall speed 64 KIAS

And remember that the wing doesn't just support the weight of the airplane, it also has to counter the downforce of the elevator. The NG has 374 lb-ft. more downward moment at this particular CG loading than the -180's which must be countered by the elevator.
Thank you Rich for the detailed explanation.
That said, I am now a little confused about my own XLS, (with custom order 40 gallon tanks so I can carry two backseat passengers) as the forward CG limit appears to start at 94.5 inches. Please see attached W&B calculator. Am I missing something here? Please advise. Thanks.
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Rich
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Re: Flying Magazine Review of DA40 NG

Post by Rich »

Don wrote:
Rich wrote:
Don wrote:It is hard for me to fathom that the increased gross weight of 242 pounds over the XLT, plus approximately four or five less square feet of wing surface area would cause such a delta in stall speed when flaps are in the fully up position. Would just that amount of difference with the wing loading cause such a large amount of stall speed change?
It's also a function of where the CG is. Remember, forward CG produces higher stall speeds and that is where the tests are performed.

Example:
DA40-180's at 2646 lb has a forward CG limit of 97.6 in., clean stall speed 53 KIAS
The NG at 2646 lb has a forward CG limit at about 95.9 in., clean stall speed 64 KIAS

And remember that the wing doesn't just support the weight of the airplane, it also has to counter the downforce of the elevator. The NG has 374 lb-ft. more downward moment at this particular CG loading than the -180's which must be countered by the elevator.
Thank you Rich for the detailed explanation.
That said, I am now a little confused about my own XLS, (with custom order 40 gallon tanks so I can carry two backseat passengers) as the forward CG limit appears to start at 94.5 inches. Please see attached W&B calculator. Am I missing something here? Please advise. Thanks.
Look at the envelope in the POH. The forward CG limit slopes back as weight increases, starting at 2161 lb to MTOW of 2646, where it’s 97.6.
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
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Re: Flying Magazine Review of DA40 NG

Post by carym »

I just saw a Republic Airlines DA40NG at our airport today, sitting next to a DA40 XLS. They must be starting the training for new pilots to fly for Republic. As Dave pointed out, the wing tips have the large winglets, but on this plane they were painted bright orange. it just looks bizarre on the white wings. Since these pilots will be training in a FADEC single engine and then in a FADEC twin (DA42) I guess they will never know how to adjust a prop control or a mixture control. So much for learning the GUMP check.
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Re: Flying Magazine Review of DA40 NG

Post by jb642DA »

Hopefully they will learn "GU"! (and "Heels on the floor")
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Re: Flying Magazine Review of DA40 NG

Post by Sandy »

jb642DA wrote...
Hopefully they will learn "GU"! (and "Heels on the floor")
After 45 years of flying I went to KRDU to take a course at LifeStyle relating to the Austro engines and their operation in the various Diamonds. While there I got to fly the DA40 NG that is on the cover of the August Flying magazine. John Armstrong was in the right seat, and he made two points... first, to accelerate to 65 kts (rather than my normal 56 kts) before rotating, and, second, to keep my heels on the floor. In my own plane I have already had to replace two right side brake pads, so I guess that keeping one's heels on the floor is something I need to do irrespective of the power plant sitting in the plane.

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Re: Flying Magazine Review of DA40 NG

Post by Rich »

jb642DA wrote:Hopefully they will learn "GU"! (and "Heels on the floor")
With my old small-rudder DA40 I typically MUST drag the right brake in the early stages of takeoff (particularly at sea level) unless the runway is plenty wide and I can start by aiming toward the right edge or if it's really long and I can ease the power in very slowly. Short, narrow runways require right brake usage to some degree.

And I usually rotate at 55, otherwise I'm skittering along the ground. I've found picking it up at about 40 KIAS is about right with two aboard in a scenario where soft field technique is desired.
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Re: Flying Magazine Review of DA40 NG

Post by TimS »

Has anyone tried a slightly slower acceleration and not drag the right brake? Bring power to 1500 RPM, enough to get the plane moving, at about 10 KIAS, go to 2000 RPM, when at 20 KIAS go full throttle....
Or some variation of this?

Tim
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