Douglas X-3 Stiletto FSX Native

[Milton Shupe]

Keith,

Good call on the different engine thrust! Yes there is a difference in thrust between SP2 & Accel.
In our F-111 project we noticed it when comparing numbers between sims.
We figured this out.. All things being equal, Accel with only 1 stage (versus 5, for testing), flight tests at sea level, standard weather, etc...
The atmosphere between SP2 and Accel are different! ( or interpretations of .air files )
Our F-111 has a configurator program to rewrite the aircraft.cfg for the following - SP2 vs. Accel, and the difference between the 5 engines available, TF-30PW-1 thru the TF-30PW-100
What we did is model each engine for correct performance in Accel then for SP2 apply a thrust_scalar =, in most cases it was around 1.12. The entry varied due to the different .air files per engine.
I had a spreadsheet with all the values but darned if I can find it It was an extensive amount of testing.

If an Accel aircraft has 5 AB stages stage 5 will be the same as SP2 with AB on. Max is max, it divides the lower stages into equal levels above the trigger.



Looked at all the effects when seeing what was going on with SP2 not showing up.
Yes.. There is an afterburner effect with 9 (+ ??, don't recall) elements in it! ( WOZZA !! )
Also noticed the slight bleed thru of one of the elements on the left side bleeding through the fuse too, only at certain view angles though.. Oh well, spend my time in cockpit LOL.

Flew that bugger a few times this morning with coffee.. WOW! that is way to wake up!
Currently at the clinic getting some anti-venom cuz she bit me a few times - LOL!

EDIT - Found the report, here --> https://www.dropbox.com/s/03u2u71mma0qrp9/F-111 SP2 vs Accel.pdf?dl=0

Roman, thanks for that explanation. We will provide a separate folder for changes for non-Accel FSX versions. Yes, there are some AB effects anomalies at some viewing angles.

 

[Milton Shupe]

... snipped ...

One other thing I noticed is the fixed needle on the compass - is it supposed to always show east?

Keith

I assume you are talking about SP2 here as the compass works fine for me in FSXA. ???

EDIT: I have asked Roman to take a look at the code; may be something there unsupported by SP2.

 

[MrZippy]

Did I and Paul do ok?
Paam

Great job, Pam! Feelin' good enough to run that marathon yet?

 

[magoo]

Did I and Paul do ok?

I think after all these years that I know enough about the FS flight model format to recognize most levels of work.

This one is good enough that I was left shaking my head thinking about (what) the original test pilots must have endured. Very evocative, and from a guy who has little to do with jets, for me this one's a desert island keeper.

To you and Paul, and the rest of the crew who contributed to the whole package, your skill, artistry, hard work and pursuit of a relevant (representational) truth are most appreciated here. My thanks expressed for the compelling and historical ride!!

Cheers!

 

[Dev One]

I assume you are talking about SP2 here as the compass works fine for me in FSXA. ???

Yes, FSX SP2 - Must look again at FSXA!

Romain - glad I'm not imagining things as far as thrust goes.

My only experience with jet thrust was with Real World Jindiviks with the Viper - there was never a POH as such for take off lengths as we had 7000 ft at Llanbedr, but there was an exercise to take it elsewhere, so a crude static thrust measurement was taken and then measurements of take off distance taken. Then using text book take off mathematics we could verify our measurements & then apply wind limits etc. Jindivik drag & weight with the trolley attached was a big difference to 'normal' aircraft, as was the braking distance for aborted take off or even trolley post separation braking distance.
By inference IIRC we found that above 60 KIAS thrust increased at least to the quoted static values.
Max rpm was limited static to avoid intake damage, but ASTA/GAF had already proposed a blow in door to help the situation - it was never used.

Interesting ain't it.

Pam, Yes you all did very well, glad to hear from you.

Keith

 

[Milton Shupe]

... snipped ...

One other thing I noticed is the fixed needle on the compass - is it supposed to always show east?

Keith

I think maybe you are referring to the slaved gyro mag compass with the green card?

That must be tuned to an ADF, otherwise it lies EAST.

I use that to line up with runway outer markers mainly with this aircraft.

 

[MZee1960]

WOW! What a difference in both the X-3 and XF-92. Basically a kick in the pants when the AB starts up! Now if I can just keep the nose from drooping slightly when trying to land, I'll be in Fat City! Thanks to Milton-Team -Roman for all their work on these projects

Can someone explain what changes need to be made to the XF-92 to get the afterburner effect to work and be seen if using FSX SP2 ?
I downloaded the original XF-92 released by Milton Shupe on June 2,2018 from here : http://www.sim-outhouse.com/sohforums/local_links.php?action=jump&catid=38&id=23667

Thank-you.

 

[warchild]

Great job, Pam! Feelin' good enough to run that marathon yet?

FaR Far from it. Give me a while ::

 

[Milton Shupe]

Can someone explain what changes need to be made to the XF-92 to get the afterburner effect to work and be seen if using FSX SP2 ?
I downloaded the original XF-92 released by Milton Shupe on June 2,2018 from here : http://www.sim-outhouse.com/sohforums/local_links.php?action=jump&catid=38&id=23667

Thank-you.

MZee,

I put together an XF-92A AB Update package for you and other XF-92A SP2 users with three items:

1) AB Gauge for the Panel/xf92a folder
2) Panel.cfg with required changes
3) Aircraft.cfg with required changes

So, unzip and put the items in their respective folders and test.
You'll know if they work as you should hear the "Bang" when the afterburner kicks in and maybe feel a surge forward.

 

[Dev One]

I think maybe you are referring to the slaved gyro mag compass with the green card?

That must be tuned to an ADF, otherwise it lies EAST.

I use that to line up with runway outer markers mainly with this aircraft.

Thank you Milton, makes sense now - not used to such new fangled things - I normally just use a simple magnetic compass!
I will try tuning it in.
Keith

 

[MZee1960]

MZee,

I put together an XF-92A AB Update package for you and other XF-92A SP2 users with three items:

1) AB Gauge for the Panel/xf92a folder
2) Panel.cfg with required changes
3) Aircraft.cfg with required changes

So, unzip and put the items in their respective folders and test.
You'll know if they work as you should hear the "Bang" when the afterburner kicks in and maybe feel a surge forward.

Thank-you, very much, Milton. I will download and test in the coming days. You're the best !

 

[MZee1960]

Just downloaded and tested it and all works OK ! Thank-you, once again.

 

[Milton Shupe]

Just downloaded and tested it and all works OK ! Thank-you, once again.

Ah, great! Thanks for the follow up.

 

[johnwillimas2]

Afterburner bleed through

A tiny quibble.... I am getting a bleed through to the outer textures from the afterburner effect, as in the picture below....

This is on FSX with DX10....

 

[Milton Shupe]

Hi John, thanks for your comment. Yes, this is a known issue and I will try to reduce it a bit.

The problem is with FSX, the effect moves left and right depending on the aircraft heading. Sometimes you see this on the left, sometimes on the right, sometimes not at all when centered.

See attached and note the center of the effect inside and the view of the effect on the outsides. I will try to reduce the effect size a bit to eliminate the issue.

EDIT: Update - issue now corrected

 

[johnwillimas2]

EDIT: Update - issue now corrected

Thanks, Milton, that's great.

John

 

[MrZippy]

Definitely a fast flier even at lower altitudes. It even tends to outrun it's own MACH envelope.

 

[warchild]

Definitely a fast flier even at lower altitudes. It even tends to outrun it's own MACH envelope.

Hmm.. Indeed.. We had a heck of a time with this specific phenomena, and we learnd a new romper room word. "Mean Aerodynamic Center". ::chucklees:: Poor Milton and the crew hvw heard this from me a million times already so I'do apologize, but this plane utilized a technology that hadnt actually been discovered yet, and this cause no end of issues, but also was the main cause for what instabilitry this plane had. Oddly, your photogrph shows this trechnology off wonderfully. you see, this thing didnt have ten foot wide wings. it had those, then it had the entire underbelly acting as a lifting surface.
This gave us some interesting aerodynamics.. The CGwould shift backwards to 25% root chord during transsonic runs, and the MAC ( Center of balance or mean aerodynamic center ) would remain at the indicated CG point 1.25 feet infront of the wings LE. this caused force to be applied further back along the chord and in a downward direction, forcing the nose to want to rise.. I tried as best i could to manage the force being ecerted upwards on the nose by varying the length of the lifting surface. When thhe actual adverse condition showed itself to be docile in nature ( comparitively ) it became more a matter of adjusting lengths and sizes to manage the effect best.

 

[Dev One]

Pam, your explanation above helps explain the phenomena I see after I have dived her to M=1 & in subsequent flight she goes like a dingbat throttle reduced or even closed. Is the MAC not resetting or the induced drag not reducing I wonder.
The other thing I was wondering, did the wings have any incidence?

Looks as if you are well on the mend & feeling better?

Keith

 

[Milton Shupe]

Pam, your explanation above helps explain the phenomena I see after I have dived her to M=1 & in subsequent flight she goes like a dingbat throttle reduced or even closed. Is the MAC not resetting or the induced drag not reducing I wonder.
The other thing I was wondering, did the wings have any incidence?

Looks as if you are well on the mend & feeling better?

Keith

Keith, these may help answer some of your questions.