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Features dropped from final production f-22

chuck4

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I believe IRST and separate cheek radars were originally included in the production configuration, but dropped before actual production to save money.
Where we're the cheek radar and IRST located? Is there any drawings or photos showing these features? I like to build a model of f-22 with these originally intended features, so I like to know where the dielectric panels for the cheek radars were going to be, what shape they were, and where the ports for IRST would have been, and what shape those were.
 

GeorgeA

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A requirement for thrust reversers for STOL was part of the original ATF requirement but was dropped before the YFs were built. For other ideas, I'd suggest a cruise through the Piccirillo book, which has a good discussion of the ATF planning and development phase.
 

flateric

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F-22 AIRST installation (bottom of the forward fuselage, seems to be quite close to F-23A design)




USAF photo courtesy Dr.Kopp

side arrays schematics from AN/APG-77 paper (proportions shown to main array is questionable, I think they should have been way smaller). you can use your deduction now thinking where provisions were left for side arrays installation
 

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chuck4

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Are the longish objects behind the chines or the one of the boxes underneath the chines the AESA antenna?
I have no idea where the space reservations were.
 

flateric

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me too
obviously not inside the racks with electronic modules which are shown above. here go forward compartment


 

chuck4

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flateric said:
F-22 AIRST installation (bottom of the forward fuselage, seems to be quite close to F-23A design)




USAF photo courtesy Dr.Kopp
So the model is flipped upside down, and the IRST window is intended to be on the bottom in the production aircraft? However, the model of radom looks to have a totally different shape from that in the production aircraft.

I also read somewhere the IRST window was at one point located at the wing roots. Was that before or after the bottom configuration shown here?
 

chuck4

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One more question. The unpainted F-22 surface shows lots of area colored a very light green. What are those?
 

sferrin

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chuck4 said:
One more question. The unpainted F-22 surface shows lots of area colored a very light green. What are those?
Could you be more specific? (Post a pic if possible.)
 

saintkatanalegacy

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think he was referring to the teal colored panels in the top right picture insert.
 

chuck4

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Yes, thr panel just above the edge of the chine is one example. there are panels of that color all over the upper surface.T
 

sferrin

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Well the teal is just primer. So I'm guessing teal means, "not a removable panel or radome".
 

fightingirish

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Hi folks,
I just found this about the Advanced IRST (AIRST or Airstar) at f-16.net.
The USAF has not yet been convinced of the usefulness of IRST, although I have tested the AAS-42 on an F-15 in the late 80's. GE and Martin Marietta Aerospace, which are now part of Lockheed Martin (LMEM) developed an IRST to the ATF program, which became the F-22A Raptor.

The IRST was canceled during the demonstration / evaluation (dem / val). The USAF believes the AN/APG-77 radar capable LPI will be able to meet all your requirements. The space, weight, power and cooling system for the IRST is still in the aircraft.

Still, LMEM won a contract to develop technology for an IRST (AirStar) with potential application in the F-22.

The LMEM tested a Advanced IRST (AirStar) for the F-22. The sensor unit (left) is protected by a window with stealth characteristics (right).
 

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Regarding AIRST, is it supposed to be mounted at the wing root or under the nose? I remember reading the LEF was moved in because of no more IRST.
 

Colonial-Marine

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Perhaps it doesn't qualify as a "feature" but it seems like the F-22's internal fuel capacity fell significantly from the YF-22 to the production F-22A. I've read numbers as high as 25,000 lbs for the YF-22 while the numbers I've seen for the F-22A range from 18,450 to 20,650 lbs. Is such a reduction normal in the transition from prototype to production aircraft in order to fit all of the avionics?
 

flanker

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USAF relaxed the range/fuel requirements. It was tradeoff for something else, can't remember what exactly. Speed or maneuverability?
 

sferrin

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flanker said:
USAF relaxed the range/fuel requirements. It was tradeoff for something else, can't remember what exactly. Speed or maneuverability?
I would guess a little of both. Compare the back end of the YF-22 to the F-22A. The rear of the F-22A is much slimmer.
 
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http://www.fighter-planes.com/f22vsf22y.jpg

According to this, the flaps were moved in due to deletion of IRST.
 

F-14D

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flanker said:
USAF relaxed the range/fuel requirements. It was tradeoff for something else, can't remember what exactly. Speed or maneuverability?
Basically, as development progressed, Lockheed came back and said, "We can give you your desired speed, range and maneuverability. Pick any two".
 

RadicalDisconnect

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Looking at this cutaway of the F-22, I'm not sure if space for the AIRST still exists (assuming that it would be at the wing roots). There doesn't seem to be any available space there.

 

TomS

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Is there any reason to think these cutaways are accurate beyond fairly general arrangements? I can't imagine that LM let the artist look at the actual production blueprints. But maybe I'm wrong.
 

Sundog

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Based on what we've seen from their IRST tests on the generic model on the previous page and the drawings on the Northrop production designs for the F-23A and the NATF, and also the F-35, it seems to me the IRST would have been in a chin located "housing" under the nose just behind the radome as well. I suppose they could have gone for more coverage in azimuth by having one located in each wing root, sort of a small lerx with faceted windows. Like a stealthy version of what we saw on the nose of the YF-12A.


I'll go through my ATF book again and see if they mention where the system was to be located, but I don't recall ever reading about where the system would be located on the airframe. I know the GD ATF submission had the RADAR system in the LERX's over the inlets, and the IRST in the nose.
 

bring_it_on

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Jane's reported in 1997 that the provisions for an IRST were still there.

An IR search and track (IRST) system was part of the original ATF requirement. It was deleted during dem/val, but the Avionics Directorate of the USAF Wright Laboratories has continued its development with Lockheed Martin as the contractor, and space, weight, power and cooling provisions for IRST are still on the aircraft. A low-observable IRST window for the F-22 was tested for stealth and durability last year. IRST is valuable for raid assessment, because of its high angular resolution. It is also useful against tactical ballistic missiles, and it can double as a thermal imaging system for ground attack.
https://www.scribd.com/doc/254885620/F-22-Janes1997
 

Sundog

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OK, the book on the ATF program by Picarillo states that the original design for Dem/Val, the one that was too heavy and never built, had the IRST system in the wing roots. I'm looking for info in the book regarding the location of the IRST on the production version.
 

bring_it_on

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Sundog said:
OK, the book on the ATF program by Picarillo states that the original design for Dem/Val, the one that was too heavy and never built, had the IRST system in the wing roots. I'm looking for info in the book regarding the location of the IRST on the production version.
I'm reading it as well :) (third time). Haven't read it for some time. But I also noticed that Lockheed originally planned to have it in the wing roots. I think Janes pretty much provides a definitive account in the late 90's of what the situation was/is with the IRST.
 

Sundog

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bring_it_on said:
I'm reading it as well :) (third time). Haven't read it for some time. But I also noticed that Lockheed originally planned to have it in the wing roots. I think Janes pretty much provides a definitive account in the late 90's of what the situation was/is with the IRST.

Oh, yeah, I haven't any doubt they made room for the system in the production version. I'm just trying to figure out if they also planned for it to be in the wing roots on the production version or under the nose. Also, until reading this book, I had never realized the biggest weight penalty for the thrust reverser was due to the cooling requirements. I had thought it was just due to the weight of the reverser itself.
 

bring_it_on

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Do you have any more information on the General Electric IRST that was being tested onboard the Lockheed test bed (Boeing 757) ( Page 116)?
 

icyplanetnhc

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flateric said:
Interestingly, the CAD image shows that several fuselage bulkhead frames behind the radome appear to have a notch cutout at the bottom. Perhaps that is to accommodate the compartment for a chin-mounted IRST? Are there any other diagrams or pictures showing that compartment or what's in it? I wonder if that compartment is still empty or if it has been used for some other purpose.
 

FighterJock

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It is a real pity that Lockheed never installed an IRST on the production F-22, I remember having the F-22 ADF flight simulator back in 1997 and that had the IRST featured.
 

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If you mean the one from DiD*, that one had also Typhoon that were 100% available ;)

*great games b/w
 

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TomcatViP said:
If you mean the one from DiD*, that one had also Typhoon that were 100% available ;)

*great games b/w
That is the one I mean TomcatViP.
 

icyplanetnhc

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Hi folks,
I just found this about the Advanced IRST (AIRST or Airstar) at f-16.net.
The USAF has not yet been convinced of the usefulness of IRST, although I have tested the AAS-42 on an F-15 in the late 80's. GE and Martin Marietta Aerospace, which are now part of Lockheed Martin (LMEM) developed an IRST to the ATF program, which became the F-22A Raptor.

The IRST was canceled during the demonstration / evaluation (dem / val). The USAF believes the AN/APG-77 radar capable LPI will be able to meet all your requirements. The space, weight, power and cooling system for the IRST is still in the aircraft.

Still, LMEM won a contract to develop technology for an IRST (AirStar) with potential application in the F-22.

The LMEM tested a Advanced IRST (AirStar) for the F-22. The sensor unit (left) is protected by a window with stealth characteristics (right).
I'm looking at the attached image and I'm not sure what to make of the aperture on the right. Is that supposed to be on the wing root or under the nose? Where did the image come from?
 

fightingirish

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Hi folks,
I just found this about the Advanced IRST (AIRST or Airstar) at f-16.net.
[...]
I'm looking at the attached image and I'm not sure what to make of the aperture on the right. Is that supposed to be on the wing root or under the nose? Where did the image come from?
The secondary source of that image, as I wrote back then in 2013, is at the forum f-16.net. Link: http://www.f-16.net/forum/viewtopic.php?p=190627
The primary source, a link or a PDF, have been deleted.
Maybe this PDF might help you:
Source: https://www.forecastinternational.com/archive/disp_old_pdf.cfm?ARC_ID=455[/QUOTE]
 

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