Some kind requests for future implementation

[Matei]

Hi,

 

I am currently flying your plane since about two weeks. We've already had our ups (or downs) regarding the ILS approaches.

• Installing the 2014 xPlane 11.41 AIRAC fixed everything. On the other hand, this very easy workaround is quite hidden between pages of posts. A sticky, next to the AIRAC already posted would make it more obvious.

Among the things that I noticed, while flying the plane (and reading the forum) is that:

• there is absolutely no P-Factor on takeoff, I read all the pro and con arguments that were presented on the forum, but I still think that a certain amount of P-Factor would be a nice addition to the plane. In the end, it has 1800 hp (850 hp output). For a comparison, the default Cessna can be quite angry on takeoff and has only 180 hp.

The second thing that I noticed is that:

• the elevator trim is completely off (at least graphically). The T/O mark is not in the right place, and with autopilot engaged, the elevator trim stays the whole flight between the TO mark and the down position. I checked the data output from xPlane and it turns out that the trim position stays only in the negative range. I find it hard to believe that the real airplane has that much up trim space available. There is also a considerably pitch up tendency above ~120 KIAS.

The last thing, is more a refinement, regarding the cruise speeds.

• In the TBM 900 brochure they present a couple of flying configurations, among which the maximum speed at FL280 (330 KTAS) and FL310 (326KTAS). While running CAVOK preset, 29.92 QNH, no winds I got the following max speeds:

 

Using experimental flight model:

Vind kias	Vind keas	Dasboard	V ktas	ISA	Wind	Temp	Alt	QNH
204.73	200	200	315.27	0	0	-40	28000	29.92
193.81	189.1	189	314.8	0	0	-46	31000	29.92

 

Using "standard" flight model:

Vind kias	Vind keas	Dasboard	V ktas	ISA	Wind	Temp	Alt	QNH
212	207	207	326	0	0	-40	28000	29.92
202	197	198	327	0	0	-46	31000	29.92

 

Regards,
Matei

[Cameron]

1 hour ago, Matei said:

I am currently flying your plane since about two weeks. We've already had our ups (or downs) regarding the ILS approaches.

• Installing the 2014 xPlane 11.41 AIRAC fixed everything. On the other hand, this very easy workaround is quite hidden between pages of posts. A sticky, next to the AIRAC already posted would make it more obvious.

I can't say I follow what you're saying here. The topic is a sticky and the very first post is the download. What am I missing? It's also the very first thread listed in the support forum.

 

1 hour ago, Matei said:

The last thing, is more a refinement, regarding the cruise speeds.

• In the TBM 900 brochure they present a couple of flying configurations, among which the maximum speed at FL280 (330 KTAS) and FL310 (326KTAS). While running CAVOK preset, 29.92 QNH, no winds I got the following max speeds:

While brochures are cool, they're also marketing. Seems to me the numbers you're posting are within proper range. Marketing is your best possible scenario, not your practical every day scenario. That includes weights and ISA. Think 330KTAS at very light weight with -20C ISA kind of stuff.

[rjb4000]

On 1/19/2021 at 8:28 PM, Matei said:

the elevator trim is completely off (at least graphically). The T/O mark is not in the right place, and with autopilot engaged, the elevator trim stays the whole flight between the TO mark and the down position. I checked the data output from xPlane and it turns out that the trim position stays only in the negative range. I find it hard to believe that the real airplane has that much up trim space available. There is also a considerably pitch up tendency above ~120 KIAS.

Did you do any research to come to the conclusion that the trim indicator is "completely off"? 

Here are some photos of the real thing: 

 

Here is a comparison between the X-Plane TBM and the real ones.. the last image is from the TBM900 PIM. I'd say it looks about right. If it's off, it's surely not "completely off". 

 

 

Edited January 21, 2021 by rjb4000

[Matei]

Hi,

Thank you for sharing the images.

I see you posted two trim configurations, out of which, the first one is with the trim up, higher than the takeoff trim.
I never reach that trim, in any flight configuration. In reality, I have to set it way closer to the DN mark than what you show in your real life photos. Actually is past what your xPlane screenshot shows, maybe one full tab thickness.
Also at take-off there is a strong change of behavior to nose up at more than 20 degrees when going over the 120 knots mark.

Would be interesting to mention where is the trim is, according to your experience, in level flight (and at which flight configuration).

 

[rjb4000]

Can you post a screenshot of your weight and balance?

[Matei]

Sure thing, maybe I get to figure out if I am doing something wrong.

All pics contain the relevant (I hope) data output from xPlane.

Firs on ground, with payload

Takeoff roll at 80 knots with QFE.

Pitch up capture. Sometimes it gets worse. This time it did not want to . I have no input applied on the yoke.

Level flight, autopilot, STD Baro, FL100 150 knots.

Same story but at 180 knots.

 

[rjb4000]

Take a look at this video (takeoff at 1:33): 

In the video, there are at least 2 people on board and full fuel tanks. After rotation, pilot sets pitch around 10 degrees for the climb. You mentioned when you depart the pitch increases and showed a screenshot of around 15 degrees nose up and 105 knots airspeed. This is expected - the takeoff trim setting is meant to allow the pilot to rotate at takeoff speed. The faster you go after that, the more the nose will want to pitch up to maintain that initial speed. The expected pilot response would be to lower the nose to the desired angle, then apply nose down trim to relieve control force. You may also find it beneficial to raise the flaps as well, since this will assist with the pitch down. 

I also noticed you are departing with 66% torque - is there a reason you used that technique?

[Matei]

Hi,

Thank you for the quick response.

Very informative video.

To answer your question, no, I have no reason to depart at 66% TRQ. I guess I was not paying attention.

On the other hand, I had no idea that a nose down command is required on departure in order to maintain the 10 degrees attitude in the real aircraft. That seemed counter intuitive to me.

[rjb4000]

No worries - the reason you need to apply nose down force as you speed up is that elevator trim is designed to hold an attitude at a specific speed.

If you're trimmed (hands off flying) for level flight at 100 knots and then you increase power and speed up to 110 knots, the airplane's nose attitude will increase, the aircraft will climb, slow down, and eventually settle on a climb attitude at 100 knots. If you reduce power, the airplane's nose will pitch down until eventually settling into a descent at 100 knots.