Taxying and RPM's

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francesco.doenz
Posts: 138
Joined: Mon Aug 03, 2015 1:10 pm
Location: Morges, Switzerland
Taxying and RPM's

Post by francesco.doenz » Mon Dec 21, 2015 9:34 am

To get the bird moving I need 80% rpm's, even a little bit more, instead of the around 60% recommended, any opinions? Is it a calibration problem of my setup?

Alvaro
Posts: 495
Joined: Mon Dec 15, 2014 2:25 pm
Re: Taxying and RPM's

Post by Alvaro » Mon Dec 21, 2015 10:13 am

Where is mentioned that recommendation?

JWNoctis
Posts: 13
Joined: Fri Dec 18, 2015 3:04 pm
Re: Taxying and RPM's

Post by JWNoctis » Mon Dec 21, 2015 10:40 am

FSX has problems with ground friction.

Install FSUIPC if you haven't already, and add these lines to your FSUIPC4.ini and try again:

[General]
PatchSIM1friction=Yes

For my current setup, the plane would start rolling as soon as the nozzles are half-closed. In fact, the engine cannot produce thrust at all if its nozzle failed open, as far as I know.

francesco.doenz
Posts: 138
Joined: Mon Aug 03, 2015 1:10 pm
Location: Morges, Switzerland
Re: Taxying and RPM's

Post by francesco.doenz » Mon Dec 21, 2015 11:41 am

Read that recommendation in the quick guide page 2.

Alvaro
Posts: 495
Joined: Mon Dec 15, 2014 2:25 pm
Re: Taxying and RPM's

Post by Alvaro » Mon Dec 21, 2015 1:50 pm

francesco.doenz wrote:Read that recommendation in the quick guide page 2.
Ok, I see...but that is part of the old documentation included in the basic T38A.

While that document (in general) is still applicable, this specific recommendation is not included in the real jet Flight Manual nor in the operational documentation (AF Manual, T-38 Flight Fundamentals) so I am not sure how accurate it could be considered...

francesco.doenz
Posts: 138
Joined: Mon Aug 03, 2015 1:10 pm
Location: Morges, Switzerland
Re: Taxying and RPM's

Post by francesco.doenz » Mon Dec 21, 2015 3:50 pm

Many thanks for your input, found the flight manual here

http://static.e-publishing.af.mil/produ ... -250v1.pdf

will be an interesting reading!

Firecapt32
Posts: 325
Joined: Mon Aug 10, 2015 7:38 pm
Location: Saginaw, MI
Re: Taxying and RPM's

Post by Firecapt32 » Mon Dec 21, 2015 3:59 pm

JWNoctis wrote:FSX has problems with ground friction.

Install FSUIPC if you haven't already, and add these lines to your FSUIPC4.ini and try again:

[General]
PatchSIM1friction=Yes

For my current setup, the plane would start rolling as soon as the nozzles are half-closed. In fact, the engine cannot produce thrust at all if its nozzle failed open, as far as I know.
The mode above, what does that actually do?
I'm a Captain..... but a different kind.

JWNoctis
Posts: 13
Joined: Fri Dec 18, 2015 3:04 pm
Re: Taxying and RPM's

Post by JWNoctis » Mon Dec 21, 2015 7:21 pm

Firecapt32 wrote:
JWNoctis wrote:FSX has problems with ground friction.

Install FSUIPC if you haven't already, and add these lines to your FSUIPC4.ini and try again:

[General]
PatchSIM1friction=Yes

For my current setup, the plane would start rolling as soon as the nozzles are half-closed. In fact, the engine cannot produce thrust at all if its nozzle failed open, as far as I know.
The mode above, what does that actually do?
Makes ground friction in FSX closer to real world and less like you were taxiing on a few inches of molasses.

There's a supposedly better fix that adds dynamic friction and sideslip friction as well, but that needed a registered copy of FSUIPC4 which adds lua support, for all I know.
Last edited by JWNoctis on Mon Dec 21, 2015 7:22 pm, edited 1 time in total.

Alpha
Posts: 282
Joined: Sat Feb 19, 2011 2:49 pm
Re: Taxying and RPM's

Post by Alpha » Mon Dec 21, 2015 7:21 pm

60% RPM is usually not enough to start taxiing. As you have to taxi out of the chocks and in most cases have to turn 90 degrees left or right 80% is a pretty good number.

JWNoctis
Posts: 13
Joined: Fri Dec 18, 2015 3:04 pm
Re: Taxying and RPM's

Post by JWNoctis » Mon Dec 21, 2015 7:26 pm

Alpha wrote:60% RPM is usually not enough to start taxiing. As you have to taxi out of the chocks and in most cases have to turn 90 degrees left or right 80% is a pretty good number.
Taxi out of the chocks...Jumping chocks does not sound like good idea to me? The one writeup I read about T-38 on code7700 does seem to indicate otherwise.

...Yep, this was a good read: http://code7700.com/t-38_v1.html

Firecapt32
Posts: 325
Joined: Mon Aug 10, 2015 7:38 pm
Location: Saginaw, MI
Re: Taxying and RPM's

Post by Firecapt32 » Mon Dec 21, 2015 7:35 pm

JWNoctis wrote:
Firecapt32 wrote:
JWNoctis wrote:FSX has problems with ground friction.

Install FSUIPC if you haven't already, and add these lines to your FSUIPC4.ini and try again:

[General]
PatchSIM1friction=Yes

For my current setup, the plane would start rolling as soon as the nozzles are half-closed. In fact, the engine cannot produce thrust at all if its nozzle failed open, as far as I know.
The mode above, what does that actually do?
Makes ground friction in FSX closer to real world and less like you were taxiing on a few inches of molasses.

There's a supposedly better fix that adds dynamic friction and sideslip friction as well, but that needed a registered copy of FSUIPC4 which adds lua support, for all I know.
I have a registered copy of FSUIPC4. I'll have to give this a try.
I'm a Captain..... but a different kind.

Alpha
Posts: 282
Joined: Sat Feb 19, 2011 2:49 pm
Re: Taxying and RPM's

Post by Alpha » Mon Dec 21, 2015 8:28 pm

JWNoctis wrote:Taxi out of the chocks...Jumping chocks does not sound like good idea to me? The one writeup I read about T-38 on code7700 does seem to indicate otherwise.
I don´t quite understand that. Usually you need more than 60% to get moving (70ish) and 80 to get moving quickly so you cann go to idle prior the 90 deg turn. You don´t want to turn with more than idle.

Never heard of anybody trying to jump the chocks.

JWNoctis
Posts: 13
Joined: Fri Dec 18, 2015 3:04 pm
Re: Taxying and RPM's

Post by JWNoctis » Tue Dec 22, 2015 4:37 am

Ahh...Guess I misunderstood!

I see!

EDIT: Just did another test. The T-38 started rolling just above idle at ~53% just as nozzles started narrowing with FSUIPC built-in friction fix with full tanks and both seat occupied.

This is probably way too little friction...Could anyone with a registered copy of FSUIPC confirm how the lua fix is working?


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