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Exhaust Nozzle Animation...


holografique

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first off, absolutely love the product. great job guys.

I did find one in-accuracy though. that is with the exhaust nozzle animation.

based on what I remember, during pre-taxi flight-check routines, one of the tasks is to run the engine up to 80% RPM and ensure proper engine operation. During my visits to McKentire AFB in SC, USA, I was about 50-70ft directly behind the flight-line while the pilots were doing their engine run tests. And during that 80% RPM engine run test, the exhaust nozzle would get very very narrow, almost entirely closed. It is my understanding that between 70-80% RPM, the nozzle closes and gets very narrow. As the pilot increases the throttle above 80% RPM, the exhaust begins to open back up again to the point where it opens fully for afterburner.

in the current sim, the animation of the exhaust nozzle does not get anywhere near the amount of closure at 80% RPM as it does in real-life.

I could not find any pictures or videos online to validate this, but I can assure you I clearly remember this very vividly during my time at McKentire AFB. Maybe one of the other members here who have experience can validate this for me.

Also, the F-16's on the flight-line were F-16C Block 50/52's

cheers.

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also, the reason why I took extra notice of it was because my job there was sound-recording, and I was in the process of recording engine start-up procedures (JSF, etc.).

if you are within 50-100ft to the outside of an F-16 and the pilot runs the engine up during pre-flight check, you can hear a loud high-pitched whistling/whining sound. I was told by the crew chief that the sound came from the exhaust nozzle blades expanding/contracting during various RPM's. It was then that I took notice that it was when the exhaust nozzle would expand/contract based on the engine RPM...

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Does the video posted by James directly answer this issue?:

http://www.forum.aerosoft.com/index.php?showtopic=20678

Basically, the video should quite clearly illustrate exactly what should happen during idle up and exhaust animation!

Please check it out...

I'm not sure in this case because the pilot is slamming it from idle directly into afterburner, and I believe the expansion/contraction reacts differently when making such quick adjustments.

what we need to see is video of the exhaust during the pre-flight engine run-up test, which they run it up to 80% rpm and leave it there for a number of seconds.

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  • 1 year later...

first off, absolutely love the product. great job guys.

I did find one in-accuracy though. that is with the exhaust nozzle animation.

based on what I remember, during pre-taxi flight-check routines, one of the tasks is to run the engine up to 80% RPM and ensure proper engine operation. During my visits to McKentire AFB in SC, USA, I was about 50-70ft directly behind the flight-line while the pilots were doing their engine run tests. And during that 80% RPM engine run test, the exhaust nozzle would get very very narrow, almost entirely closed. It is my understanding that between 70-80% RPM, the nozzle closes and gets very narrow. As the pilot increases the throttle above 80% RPM, the exhaust begins to open back up again to the point where it opens fully for afterburner.

in the current sim, the animation of the exhaust nozzle does not get anywhere near the amount of closure at 80% RPM as it does in real-life.

I could not find any pictures or videos online to validate this, but I can assure you I clearly remember this very vividly during my time at McKentire AFB. Maybe one of the other members here who have experience can validate this for me.

Also, the F-16's on the flight-line were F-16C Block 50/52's

cheers.

this is correct saw all F-16 s,P&W, nozzles act this way,is there a possibility to change this as in real life

in fact I grew up with the Viper as they fly around nearby

and I studied a litte bit,in fact the Mlu version with P&W engine gives the follow rpm vs nozzle position

at 80% RPM this will be 20% Nozzle,at 90% RPM at 10% nozzle until 100% full mil fully closed

Below 80% RPM variation will be between 30 and below to full open position

It would be great to see the viper exhaust nozzle act this way

I m not a programmer so dont nothing about it,is there somebody who can help me out

thanks away

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Everyone - The F100 exhaust nozzle is driven by 13th stage bleed air. The "whine" is produced by the air leaving the Convergent Exhaust Nozzle Control (CENC) exhaust tube. The system is very light weight and actuates the nozzle using flex-shafts. The CENC spins the shafts like an air wrench to open or close the nozzle. On a snap acceleration or deceleration, the CENC “Whines” as the nozzle moves.

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Everyone - The F100 exhaust nozzle is driven by 13th stage bleed air. The "whine" is produced by the air leaving the Convergent Exhaust Nozzle Control (CENC) exhaust tube. The system is very light weight and actuates the nozzle using flex-shafts. The CENC spins the shafts like an air wrench to open or close the nozzle. On a snap acceleration or deceleration, the CENC "Whines" as the nozzle moves.

sounds right to me RPGRYNN

thanks for the information

but the question is how to get the right nozzle animation in this bird?

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  • 3 weeks later...

sounds right to me RPGRYNN

thanks for the information

but the question is how to get the right nozzle animation in this bird?

I tried every possible way to change it but as I said I m not a programmer

so can somebody outhere help me a little bit to figure this out to make this baby as real as it can

by the way,I dont have sleepless nights of it :-)only the fact to get it as close to the real viper

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  • 3 months later...

I tried every possible way to change it but as I said I m not a programmer

so can somebody outhere help me a little bit to figure this out to make this baby as real as it can

by the way,I dont have sleepless nights of it :-)only the fact to get it as close to the real viper

Pratts and GE engines are similar however the GE engine doesn't have the wizzle noise. I've been a crew chief on F-16's for seventeen years now and worked both engines. I prefer the GE's over Pratts. For game sake it doesn't matter. On the GE engines just after start-up the pilot will do a "SEC" check. With the flip of a switch the nozzle will close. Once I tell the pilot the nozzle is closed and clear him for run-up, he then will advance the throttle to 70-80% until he gets an indication the SEC engaged. As he retards the throttle to idle, the nozzle opens up due that the pilot is retarding the nozzle and he flips the switch back to "PRI". After this check is completed then comes the EPU check. This is non-functional in the Aerosoft product. In fact, I have never seen it fuctional in any simulation game. Most likely due to it being the system that it is and what it does. That's all I can say about that subject.

Jack Thomas

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Thanks Jack

Correct as you said

the exhaust animation in this sim is in almost full open position,if is in the air or ground at 80% RPM it should be almost fully closed or at least 20% open

but hey its a sim and there has a lot to be desired(too much)!!! see my post Final Thoughts

Polly ®

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I know it’s a little frustrating about the nozzle, but they are fighting with the way MSFS X is designed. Most of the aircraft flown in this environment live with just one nozzle schedule and most are fixed in area (787 has a fixed nozzle for both of its engines).

All - Here's a thread that explains F-16 nozzle operation pretty well:

http://www.f-16.net/index.php?name=PNphpBB2&file=viewtopic&p=129087

I think the difficulty with Noz Pos logic is the modeling in the .air, .cfg and gauge files required.

On take-off, with the landing gear handle positioned down, the nozzle is commanded near full open until the throttle moves well beyond idle, then nozzle position drives down to its min opening (Note: past 80% RPM, the parking brake releases). With the landing gear handle positioned up, the nozzle stays very tight optimizing thrust.

You have to model it based on the landing gear handle position. If Aerosoft picks up the gauntlet with this, it would make flying the sim a whole lot better. (Currently, the nozzle is running the Landing Gear Down schedule all the time).

On short final the thrust will decay significantly when the nozzle “Pops Open” on transition from “Optimum-in-flight Thrust” to “Low Thrust – High Fan Stall Margin Operation” with selection of landing gear down on the real thing and most flight simulators (This is important to properly control descent and stay on glide path).

The current set-up is ok when stabilized on final but is not accurate with the gear up (in-flight, the throttle can roll back to idle with the gear up resulting in a nozzle position of less than 20%)

The average MSFS X user will not have the tools necessary to “fix” the .air, .cfg and gauge files.

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  • 1 year later...

Hi Shaun

Just a note to "say" and encourage.

Even after a few years and much growth in complexity of add-ons for FSX, your Viper is still a beauty.

I am wowed by the VC-pilot animation combo in your product...nothing like it.

The Viper is still the prettiest jet in RW tactical aviation, with enthusiasts just excited about it as they were when it went operational 30 plus years ago. The latest block versions will keep it tactically effective for a couple more decades at least.

In my opinion, should Aerosoft decide to update this beauty in any way, its a win for the FSX community and would be a $$$ boost for Aerosoft.

Merry Christmas and happy new year to the team at Aerosoft & thank you.

paul

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