• Hi Guest! Forum rules have been updated. All users please read here.

F-16 Inlet Question

KJ_Lesnick

ACCESS: Top Secret
Joined
Feb 13, 2008
Messages
1,033
Reaction score
26
The F-16 inlet is a mixed-compression (at least two-shocks in the duct) inlet right?

KJ_Lesnick
 

FalconPilot

ACCESS: Restricted
Joined
Jul 31, 2008
Messages
2
Reaction score
0
I don't remember from my aero classes...but I did fly the F16...and always understood it to be a "simple" inlet...all subsonic flow inside the inlet. Isn't the plate above the inlet to create the shock so that all flow is subsonic?
MMO is 2.05, 800KCAS at low altitudes.
Also - there are two inlets...SI (small inlet) and BI (big inlet). The latter added 6 inches to each side of the "smile" and was for the increased mass flow needed for the GE engines (F110-100/129/134). I flew GEs with both SI and BI - and it was amazing the thrust increase just from the extra air.
 

Trident

ACCESS: Top Secret
Senior Member
Joined
May 8, 2006
Messages
1,018
Reaction score
250
Yes, a simple pitot inlet as far as I know.
 

KJ_Lesnick

ACCESS: Top Secret
Joined
Feb 13, 2008
Messages
1,033
Reaction score
26
Kind of odd that they managed to make a pitot-inlet work effectively at high-speed. From what I was told the F-16 had great acceleration at high-supersonic speeds,

KJ
 

overscan (PaulMM)

Administrator
Staff member
Joined
Dec 27, 2005
Messages
12,364
Reaction score
3,400
KJ_Lesnick said:
Kind of odd that they managed to make a pitot-inlet work effectively at high-speed. From what I was told the F-16 had great acceleration at high-supersonic speeds,

KJ

Transonic and low supersonic, yes. Mach 2, not so much.
 

KJ_Lesnick

ACCESS: Top Secret
Joined
Feb 13, 2008
Messages
1,033
Reaction score
26
You know, looking at that duct, it looks like it has a notable convergent divergent shape to it. Could be wrong here but that generally looks like it wouldn't be subsonic from the entry to the exit.



Could be wrong though


KJ Lesnick
Let's hope I don't get a heart-attack :p
 

KJ_Lesnick

ACCESS: Top Secret
Joined
Feb 13, 2008
Messages
1,033
Reaction score
26
Dammit, the image didn't post...

How do I post an image on this site?
 

flateric

ACCESS: Above Top Secret
Staff member
Top Contributor
Senior Member
Joined
Apr 2, 2006
Messages
9,046
Reaction score
873
http://www.secretprojects.co.uk/forum/index.php/topic,2185.msg24016.html#msg24016
 

KJ_Lesnick

ACCESS: Top Secret
Joined
Feb 13, 2008
Messages
1,033
Reaction score
26
This was the picture I wanted to post
 

Attachments

  • DSCN0778.jpg
    DSCN0778.jpg
    187.4 KB · Views: 183

flateric

ACCESS: Above Top Secret
Staff member
Top Contributor
Senior Member
Joined
Apr 2, 2006
Messages
9,046
Reaction score
873
F-16 inlet (both 'old' "small mouth" Normal Shock Inlet (NSI) and 'new' "big mouth" Modular Common Inlet Duct (MCID)) are Normal Shock Inlets. http://www.habu2.net/vipers/viperblocks/
It's convergent divergent diffuser inlet actually.
I'm attaching some pics that can make situation more clear.
 

Attachments

  • mcid.jpg
    mcid.jpg
    48.4 KB · Views: 344
  • nsi.jpg
    nsi.jpg
    33.1 KB · Views: 342
  • Convergent4.GIF
    Convergent4.GIF
    3.7 KB · Views: 326
  • F-16 MCID-771 inlet.jpg
    F-16 MCID-771 inlet.jpg
    35.1 KB · Views: 201
  • F-16.79 inlet.jpg
    F-16.79 inlet.jpg
    24 KB · Views: 202
  • YF-16 inlet cross-sections.jpg
    YF-16 inlet cross-sections.jpg
    19.9 KB · Views: 184

KJ_Lesnick

ACCESS: Top Secret
Joined
Feb 13, 2008
Messages
1,033
Reaction score
26
flateric said:
F-16 inlet (both 'old' "small mouth" Normal Shock Inlet (NSI) and 'new' "big mouth" Modular Common Inlet Duct (MCID)) are Normal Shock Inlets. http://www.habu2.net/vipers/viperblocks/
It's convergent divergent diffuser inlet actually.
I'm attaching some pics that can make situation more clear.

I'm actually more confused!

The second picture appears to show multiple shock-waves, and the 4th picture shows clearly "Oblique Shock" which is a shockwave that slows flow from a supersonic to a lower, but still supersonic speed... not a normal shock which slows you down from a supersonic to a subsonic speed...

While I'm at it, I might as well ask some other questions
-What's that thin rod-like thing in the inlet duct (standing vertical in the middle of the duct)?
-What's the ECS-inlet?
-In the third image on the underside of the fuselage ahead of the intake are several markers (HRF3/F14, HRF2/F1, HRF1/F13)


KJ_Lesnick
 

Trident

ACCESS: Top Secret
Senior Member
Joined
May 8, 2006
Messages
1,018
Reaction score
250
KJ_Lesnick said:
The second picture appears to show multiple shock-waves, and the 4th picture shows clearly "Oblique Shock" which is a shockwave that slows flow from a supersonic to a lower, but still supersonic speed... not a normal shock which slows you down from a supersonic to a subsonic speed...

True. Those pictures you mention probably apply only to the J-79 powered F-16-79 as indicated by the file name. That inlet seems to be slightly different to the standard Falcon intake, looks like it used an oblique shock followed by a curved isentropic compression ramp to slow the air to subsonic speeds before entering the divergent duct section of the standard F-16 inlet. I'm not sure whether the latter has a convergent section at all.

KJ_Lesnick said:
-What's the ECS-inlet?

Environmental Control System?
 

r16

ACCESS: Secret
Joined
Apr 27, 2007
Messages
377
Reaction score
10
ı don't have anything to say but I do remember that the J-79 engined aircraft "had the shocks" , can't truly translate it from the idea in my mind in Turkish , but the rest of the F-16s had simple inlets .
 

Sundog

ACCESS: Top Secret
Senior Member
Joined
Aug 2, 2006
Messages
2,820
Reaction score
266
The F-16's inlet is a pitot inlet and the bar in the middle, based on what I've been told, is a heater for anti-icing.
 

flateric

ACCESS: Above Top Secret
Staff member
Top Contributor
Senior Member
Joined
Apr 2, 2006
Messages
9,046
Reaction score
873
"...a thin, centerline, airfoil-shaped tension strut member
inside the cowl, which minimizes cowl deflections under load and allows a lighter
and less costly structural design. Flow quality is not affected by the strut."

YF-16 INLET DESIGN AND PERFORMANCE
J. E. Hawkins
Senior Propulsion Engineer
General D'ynamics' Fort Worth Division
Fort Worth, Texas

AIAA 74-1062
 

ouroboros

ACCESS: Secret
Joined
Feb 2, 2008
Messages
353
Reaction score
6
And now for something completely different...
 

Attachments

  • 1141508432973.jpg
    1141508432973.jpg
    48.9 KB · Views: 259
  • 1173781094586.jpg
    1173781094586.jpg
    30.3 KB · Views: 226
  • 1175507902616.jpg
    1175507902616.jpg
    24.2 KB · Views: 217
  • DSI-litho.jpg
    DSI-litho.jpg
    22.5 KB · Views: 375
  • f-16ds.JPG
    f-16ds.JPG
    9 KB · Views: 253
  • F16_DSI_06.jpg
    F16_DSI_06.jpg
    30.5 KB · Views: 374
  • F16_DSI_08.jpg
    F16_DSI_08.jpg
    27 KB · Views: 395

dannydale

ACCESS: Secret
Joined
May 13, 2007
Messages
222
Reaction score
15
Mach 2 in an F-16? That's impressive; I thought it topped out around M1.6. That inlet design looks dead sexah, too.
 

Sundog

ACCESS: Top Secret
Senior Member
Joined
Aug 2, 2006
Messages
2,820
Reaction score
266
"...a thin, centerline, airfoil-shaped tension strut member
inside the cowl, which minimizes cowl deflections under load and allows a lighter
and less costly structural design. Flow quality is not affected by the strut."

Thanks, I had wondered about that, but didn't have any evidence for it.
 

KJ_Lesnick

ACCESS: Top Secret
Joined
Feb 13, 2008
Messages
1,033
Reaction score
26
If the F-16's inlet was highly limited in speed, where did all that stuff I heard awhile back online about the F-16 accelerating particularly well at supersonic speed (something a typical pitot-type inlet wouldn't be able to do very well) come from? ???


Kendra Lesnick
 

RAP

ACCESS: Top Secret
Top Contributor
Senior Member
Joined
Jan 29, 2008
Messages
686
Reaction score
391
M2.2 inlet design for F-16. May be similar to what was installed on the F16/79.
 

Attachments

  • scan0011.jpg
    scan0011.jpg
    317.2 KB · Views: 185

gtg947h

ACCESS: Confidential
Joined
Apr 10, 2008
Messages
90
Reaction score
11
KJ_Lesnick said:
If the F-16's inlet was highly limited in speed, where did all that stuff I heard awhile back online about the F-16 accelerating particularly well at supersonic speed (something a typical pitot-type inlet wouldn't be able to do very well) come from? ???


Kendra Lesnick

It wasn't a pitot inlet, really. There is a compression ramp (which also serves as a boundary layer splitter), but it was fixed at one setting (probably optimized for M1-1.2 or so, I'd guess). Getting good higher supersonic performance means you'll want a variable inlet ramp.
 

sferrin

ACCESS: USAP
Senior Member
Joined
Jun 3, 2011
Messages
13,390
Reaction score
1,433
gtg947h said:
KJ_Lesnick said:
Getting good higher supersonic performance means you'll want a variable inlet ramp.

Neither the XF8U-3 nor F-22 have a variable inlet ramp and have no problem with Mach 2+ speeds. There is more than one way to skin a cat.
 

Richard N

Lost in the Sky
Senior Member
Joined
Jun 18, 2009
Messages
506
Reaction score
279
F-16 VARIABLE RAMP-INLET Conformal IIIA
 

Attachments

  • RN VRI 01e.JPG
    RN VRI 01e.JPG
    402 KB · Views: 30
  • RN VRI 02e.JPG
    RN VRI 02e.JPG
    402.6 KB · Views: 26
  • RN VRI 03e.JPG
    RN VRI 03e.JPG
    398.6 KB · Views: 25
  • RN VRI 04e.JPG
    RN VRI 04e.JPG
    555.5 KB · Views: 27
  • RN VRI 05e.JPG
    RN VRI 05e.JPG
    273.2 KB · Views: 22
  • RN VRI 06e.JPG
    RN VRI 06e.JPG
    448.3 KB · Views: 22
  • RN VRI 07e.JPG
    RN VRI 07e.JPG
    393.6 KB · Views: 24
  • RN VRI 08e.JPG
    RN VRI 08e.JPG
    306.7 KB · Views: 25
  • RN VRI 09e.JPG
    RN VRI 09e.JPG
    276.4 KB · Views: 25
  • RN VRI 10e.JPG
    RN VRI 10e.JPG
    247.9 KB · Views: 22

Similar threads

Top