A/s 300 pwr 80%

[hamidsaif70]

After installation adv and tackpack:

According to sec2 descent procedure, aircraft must descent at 300kt and pwr80%
But even shallow rate of climb observed...
Not momentarily, continuously
How is it possible?

[JonathanBleeker]

Is it sustaining 300kts in that shallow climb? What's your fuel weight and payload?

[Alvaro]

After installation adv and tackpack:

According to sec2 descent procedure, aircraft must descent at 300kt and pwr80%
But even shallow rate of climb observed...
Not momentarily, continuously
How is it possible?

On the numbers, the adv model is unable to sustain 1g flight at 80%rpm and at high altitudes. Even less to climb.

The procedure is:
1) set engines at 80%
2) allow airspeed to reduce
3) once slightly above 300kcas start applying trim down smoothly until 300 airspeed stabilized

If you're NOT using speed brakes, the descent i.e. from 30kft will take about 12.5 minutes. That supposes an initial smooth descent rate of - 2400 fpm.

If you DO extend the speed brakes, you'll have to trim overcoming the resulting pitch up effect.

Finally, you have to bear in mind that those charts are quite theoretical and are intended for descents from high altitudes. This is, their accuracy and validity will start degrading as you are getting closer to the ground where the engine thrust increases.
Weight is not accounted either and it does affect excess power for a given rpm setting.

[hamidsaif70]

After installation adv and tackpack:

According to sec2 descent procedure, aircraft must descent at 300kt and pwr80%
But even shallow rate of climb observed...
Not momentarily, continuously
How is it possible?

On the numbers, the adv model is unable to sustain 1g flight at 80%rpm and at high altitudes. Even less to climb.

The procedure is:
1) set engines at 80%
2) allow airspeed to reduce
3) once slightly above 300kcas start applying trim down smoothly until 300 airspeed stabilized

If you're NOT using speed brakes, the descent i.e. from 30kft will take about 12.5 minutes. That supposes an initial smooth descent rate of - 2400 fpm.

If you DO extend the speed brakes, you'll have to trim overcoming the resulting pitch up effect.

Finally, you have to bear in mind that those charts are quite theoretical and are intended for descents from high altitudes. This is, their accuracy and validity will start degrading as you are getting closer to the ground where the engine thrust increases.
Weight is not accounted either and it does affect excess power for a given rpm setting.

Hello sir...
Yes you are right but its not the answer of my question.
Phantom should not capable to fly straight and level while no decelerating.
My point is that why i can not descend by 80%rpm while maintaining constant airspeed?that its not actually happening in flight.

In TR/phase 1G stall exercise is:
Reduce A/S 200kt
Set pwr to 80%
Maintain vvi zero, A/S will bleed off and approach to stall indications..., then recover the maneuver

In my case, it seems engine thrust is too high enough and never allow to bleed off the airspeed,

"If you're NOT using speed brakes, the descent i.e. from 30kft will take about 12.5 minutes. That supposes an initial smooth descent rate of - 2400 fpm"
I wished it works but unfortunately did not.

Whitout installing adv, everything about pwr checked and was ok.

[JonathanBleeker]

screenshot of your cockpit? Press Print Screen, then Ctrl V in paint or some other image editor, and save the file. Then upload it here.

[Alvaro]

In my case, it seems engine thrust is too high enough and never allow to bleed off the airspeed,

"If you're NOT using speed brakes, the descent i.e. from 30kft will take about 12.5 minutes. That supposes an initial smooth descent rate of - 2400 fpm"
I wished it works but unfortunately did not.

Ok. I have checked it and was able to replicate it.
I will look into this issue but I cannot guarantee that a fix for it will happen any time soon. Sorry.

[hamidsaif70]

screenshot of your cockpit? Press Print Screen, then Ctrl V in paint or some other image editor, and save the file. Then upload it here.

Hi sir,
Is it still necessary to send screeshot?

[JonathanBleeker]

Nope. Alvaro replicated and confirmed the bug.