DA40NG

Open for questions of visitors of DAN. Posts of our guests are on moderation queue.

Moderators: Rick, Lance Murray

User avatar
Rich
5 Diamonds Member
5 Diamonds Member
Posts: 4592
Joined: Mon Aug 30, 2010 12:40 pm
First Name: Rich
Aircraft Type: DA40
Aircraft Registration: N40XE
Airports: S39 Prineville OR
Has thanked: 145 times
Been thanked: 1180 times

Re: DA40NG

Post by Rich »

CFIDave wrote:The reason the DA40 XL failed spin testing with winglets was because of the high polar moment of inertia of the extended range (50 gal) fuel tanks located out near the wingtips. Because the DA 40 NG is much more fuel-efficient than a Lycoming DA40, it doesn't need the outboard wing tanks of the XL/XLS/XLT, with the NG's fuel capacity of only 39 instead of 50 gallons in the wings. That's why the NG can pass spin certification tests with winglets.

Here's a video showing Diamond's flight tests of the DA40 NG doing stall and spin testing:
https://www.youtube.com/watch?v=GQXLUaA3yo4
Ah, but:

The DA40 TDI never got winglets AND with extended tanks (i.e. 39 gal) it has the same aft CG limit as the 50 gal. IO360's.

And the NG has the most restrictive rearward CG limit of all, regardless of fuel capacity. Why is that, anyway?
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
User avatar
TimS
5 Diamonds Member
5 Diamonds Member
Posts: 553
Joined: Thu Dec 02, 2010 1:10 am
First Name: Timothy
Aircraft Type: OTHER
Aircraft Registration: N1446C
Airports: 6B6 Stowe MA
Has thanked: 94 times
Been thanked: 97 times

Re: DA40NG

Post by TimS »

All,

This is way outside area; however, having asked an engineer who designed winglets and would be involved in re-engine the Aerostar. We discussed CG issues for the engines; here is what he told me (as well as I can rememebr)
Part of aft CG limit is the available down force produced by the tail feathers.
If the nose is to heavy and there is insufficient down force some spin and other flight conditions are not recoverable.
Further, depending on the weight actual location; polar forces come into play. The greater the polar forces, the greater the force required by the tail to overcome/stop the spin.
Lastly, aft CG can be limited due to a lack of down force for flaring and landing.

Tim
User avatar
Rich
5 Diamonds Member
5 Diamonds Member
Posts: 4592
Joined: Mon Aug 30, 2010 12:40 pm
First Name: Rich
Aircraft Type: DA40
Aircraft Registration: N40XE
Airports: S39 Prineville OR
Has thanked: 145 times
Been thanked: 1180 times

Re: DA40NG

Post by Rich »

TimS wrote: Lastly, aft CG can be limited due to a lack of down force for flaring and landing.
Tim
No, (limiting the discussion to tricycle-gear A/C) as CG moves aft the elevator needs to provide less down-force. Limits on aft CG and up-elevator travel are typically influenced by stall-regime behavior. Limits on aft CG can also be a consequence of limits on the elevator/horizontal stabilizer ability to produce nose-down rotation. As in stall/spin recovery, for example.

Maybe I answered my own question. Perhaps the reason for the more limited aft CG is that with the winglets in place, forward-stick for spin recovery is only satisfactory if the CG is limited to this more restrictive station.
Last edited by Rich on Fri Feb 16, 2018 3:33 pm, edited 1 time in total.
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
User avatar
TimS
5 Diamonds Member
5 Diamonds Member
Posts: 553
Joined: Thu Dec 02, 2010 1:10 am
First Name: Timothy
Aircraft Type: OTHER
Aircraft Registration: N1446C
Airports: 6B6 Stowe MA
Has thanked: 94 times
Been thanked: 97 times

Re: DA40NG

Post by TimS »

Rich wrote:
TimS wrote: Lastly, aft CG can be limited due to a lack of down force for flaring and landing.
Tim
No, (limiting the discussion to tricycle-gear A/C) as CG moves aft the elevator needs to provide less down-force. Limits on aft CG and up-elevator travel are typically influenced by stall-regime behavior. Limits on aft CG can also be a consequence of limits on the elevator/horizontal stabilizer ability to produce nose-down rotation. As in stall recovery, for example.
Good point, I was going on memory and did not think it through. :D

Tim
Antoine
5 Diamonds Member
5 Diamonds Member
Posts: 2043
Joined: Fri Oct 15, 2010 11:00 pm
First Name: Antoine
Aircraft Type: OTHER
Aircraft Registration: N121AG
Airports: LSGG
Has thanked: 87 times
Been thanked: 220 times

Re: DA40NG

Post by Antoine »

Funny, the more we discuss this the more it becomes obvious to me that the most balanced, most modern DA40 variant would be the... CDI-155.
All Diamond would have to do is "unfreeze" the G1000 avionics and give it a small MTOW bump.
Then you get the benefits of a modern diesel engine, a perfectly balanced aircraft, good useful load (relatively) and a beautifully designed cowling. I flew a few hours in the 135 HP version. It is a dog, but very pleasant to hand fly once airborne...
If I were in the market today, I'd buy an early DA40 TDI with timed out engine, refurbish it, upgrade avionics to GTN750 / G5 / iPad and add the CDI-155 and a composite prop.
User avatar
CFIDave
5 Diamonds Member
5 Diamonds Member
Posts: 2678
Joined: Wed Nov 07, 2012 3:40 pm
First Name: Dave
Aircraft Type: OTHER
Aircraft Registration: N333GX
Airports: KJYO Leesburg VA
Has thanked: 231 times
Been thanked: 1473 times

Re: DA40NG

Post by CFIDave »

I think an even better DA40 would be an NG with the AE330 180 hp Austro engine (E4P-C) and one inch bigger diameter prop from the DA62 -- essentially the same 168 hp AE300 engine of the NG with different software to permit increased turbo boost pressure. It would weigh the same as today's DA40 NG with few if any changes required to the airframe, but the additional 12 hp from more turbo boost might improve climb rate by an additional 100-200 fpm to around 1000 fpm all the way to 12,000 feet or so, and add a couple of knots TAS at lower altitudes. Of course if you chose to run it at the AE330's 95% max continuous power, it would burn an additional 1 gph (up to around 9 gph) compared to the AE300 of today's DA40 NG -- you don't produce more hp for nothing. However at lower power levels fuel consumption with the AE330 is the same as today's very economical AE300.

(The DA42-VI would also benefit from AE330 engines, but as with the DA40 NG, Diamond would need to invest in additional testing and re-certification with more powerful engines -- since more power would change things like V-speeds. A DA42-VI with AE330s might out-perform a heavier DA62 with the same engines.)

In my experience Austro diesels run slightly smoother, quieter, and are even easier starting than Thielert/Technify/Continental diesels I've flown in DA42 TDIs. Also no black smoke on startup with Austros.
Epic Aircraft E1000 GX
Former DA40XLS, DA42-VI, and DA62 owner
ATP, CFI, CFI-I, MEI
User avatar
reinhardj
3 Diamonds Member
3 Diamonds Member
Posts: 78
Joined: Wed May 20, 2015 7:56 pm
First Name: Reinhard
Aircraft Type: DA40D
Aircraft Registration: DEWDI
Airports: EDWQ
Has thanked: 20 times
Been thanked: 31 times

Re: DA40NG

Post by reinhardj »

Antoine wrote:Funny, the more we discuss this the more it becomes obvious to me that the most balanced, most modern DA40 variant would be the... CDI-155.
All Diamond would have to do is "unfreeze" the G1000 avionics and give it a small MTOW bump.
Then you get the benefits of a modern diesel engine, a perfectly balanced aircraft, good useful load (relatively) and a beautifully designed cowling. I flew a few hours in the 135 HP version. It is a dog, but very pleasant to hand fly once airborne...
If I were in the market today, I'd buy an early DA40 TDI with timed out engine, refurbish it, upgrade avionics to GTN750 / G5 / iPad and add the CDI-155 and a composite prop.
Antoine,
I fully agree. We plan to replace the CD-135 by the CD-155 at the end of this year. Especially with the new prop the performance is very good. The disadvantages of the Austro compared to the CD have been discussed. To me the Austro is a step back in technology at least in two respects: weight and operability (and meanwhile also TBR). The major disadvantage of the TDI is the limited MTOW of 1150kg, the mod for higher MTOW as for the Lycoming is not available for the TDI. We are presently investigating, if the higher MTOW modification (1199kg) can be made available for the TDI, at least for planes with the CD-155.
Reinhard
DA40D, S/N D4.338
G1000, GDU 12.03, WAAS, GTX 345, SVT, Safetaxi, PilotPak
User avatar
TimS
5 Diamonds Member
5 Diamonds Member
Posts: 553
Joined: Thu Dec 02, 2010 1:10 am
First Name: Timothy
Aircraft Type: OTHER
Aircraft Registration: N1446C
Airports: 6B6 Stowe MA
Has thanked: 94 times
Been thanked: 97 times

Re: DA40NG

Post by TimS »

reinhardj wrote:Antoine,
I fully agree. We plan to replace the CD-135 by the CD-155 at the end of this year. Especially with the new prop the performance is very good. The disadvantages of the Austro compared to the CD have been discussed. To me the Austro is a step back in technology at least in two respects: weight and operability (and meanwhile also TBR). The major disadvantage of the TDI is the limited MTOW of 1150kg, the mod for higher MTOW as for the Lycoming is not available for the TDI. We are presently investigating, if the higher MTOW modification (1199kg) can be made available for the TDI, at least for planes with the CD-155.
1. Weight I get. The AE300 has the iron engine block from BMW versus a new casting aluminum block that CD155 uses.
2. What is the operational differences? Both are FADEC.
3. The AE300 has fewer and less MX events. So if that was comment about operations, I am confused about the definition of easier operarion.
4. The CD engines have TBR. AE300 has a TBO.

So what did I miss?

Tim
User avatar
Chris
5 Diamonds Member
5 Diamonds Member
Posts: 935
Joined: Sat Jun 19, 2010 3:34 am
First Name: Chris
Aircraft Type: DA42NG
Aircraft Registration: N449TS
Airports: KHIO
Has thanked: 1050 times
Been thanked: 480 times

Re: DA40NG

Post by Chris »

Moderator note: This thread has been getting a bit out of hand so I moved several of the most recent off-topic posts to a "Horsepower debate" thread in Hangar Talk. If you have something relevant to the original poster's question regarding DA40NG that hasn't already been covered by the prior 148 posts, by all means post it here.
Chris
N449TS / DA42-NG / 42.AC049
KHIO
jb642DA
4 Diamonds Member
4 Diamonds Member
Posts: 313
Joined: Thu Feb 16, 2017 5:16 pm
First Name: John
Aircraft Type: OTHER
Aircraft Registration: N2691Y
Airports: KPTK KDTW
Has thanked: 51 times
Been thanked: 143 times

Re: DA40NG

Post by jb642DA »

Good move Chris!
Looking!
1980 414A - N2691Y (sold)
DA62 - N100DA 62.078 (sold)
DA42TDi - N742SA 42.AC112 (sold)
Post Reply