F-4E(S) & F-4X

roberto_yeager

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Any info??? Photos?? Drawings???

They are very strange projects, only 3 F-4E(S) build for Israel, and only a project about the F-4X.

Thanks a lot.


1Saludo
 

Archibald

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Joe Baugher
http://home.att.net/~jbaugher1/f4_29.html

This mutated Phantom would have been quite impressive...
 

shivering

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Re: F-4E(S), F-4X, & RF-4X

Cannot seem to find any good 3-view drawings of these
projects................can anyone help?

I will scrounge about for some pics.

A big thank you in advance for any help.


Shivering
 

Antonio

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International Air Power Review Volume 19 ;)
 

shivering

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There are a couple side elevation drawings only, in color,
of the Israeli F-4E(S) here:


http://wp.scn.ru/en/ww3/f/59/89/1


Shivering
 

Antonio

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Tonight I'll post some info from Air Power
 

GTX

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I have a complete article on it (Air International July 1985) if you're interested - I could probably scan it and e-mail it to you (accidently posting some pics here in the process).

Regards,

Greg
 

dan_inbox

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Re: F-4E(S), F-4X, & RF-4X

shivering said:
Cannot seem to find any good 3-view drawings of these projects................ can anyone help?
RF-4E(S) is not a 'project', it was actually built. Three planes were converted, 1st flight 1975.
It was named Shablool (snail) in the heyl ha avir.
It served a long time, and was retired recently.

Interestingly, even though they are recce planes supposed to avoid combat, Shablool 498 (now preserved at the Khatzerim museum) is credited with an air victory. An Iraqi interceptor tried to pursue it, managed to run himself out of fuel, and crashed.
 

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hs1216

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As I recall, the F-4X was supposed to be a mach 3+ phantom, basically a Foxbat killer. Israel saw it as an answer to the Egyptian based MiG-25 recon aircraft, but the USAF canceled the project in order to keep the field open for the F-15.
 

dan_inbox

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Correct. The F-4X was a recce platform, not a 'Foxbat killer'.
Actually, it did not even have a radar.
 

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Antonio

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Gentlemen,

there is a bit of confussion here ???. We are talking about three related but different designs


F-4X

By 1971, the F-4E was not capable to intercep the MiG-25. It was a challenge for Israel AF who faced reccon flights from Egypt.
Israel concluded that the only solution at their hands was the application of Pre-Compressor Cooling technology to increase the GE J79 thurst. The USAF financed General Dynamics to develop a PCC Phantom, resulting in the F-4X project. The most significative modifications from F-4E were the dramatically enlarged and complex intakes, and the water tanks on top of the fuselage (you can see it at attached profile on on dan_inbox's post). Expected performance was Mach 3.2 dash and Mach 2.4 cruise. It would have been a "Foxbat hunter" but that beast was also a threat for the F-15 program. USA Congress was taking several long looks at both the F-14 and F-15 programs during 1971 with the goal of eliminating one of them to save money. F-15A rolled out of McDD's St Louis plant on June 26, 1972. Thus, the F-4X was cancelled and Israel get its MiG-25 interceptor with the F-15A Baaz supplied in 1975.


RF-4X

F-4X speed performance so brilliant (even the F-15 could not perform Mach 3.2 dash or Mach 2.4 cruise) that General Dynamics forwarded to the USAF a proposal to develop a reconnaissance version with a new nose section from which radar and cannon would were removed. The nose accommodated the General Dynamics HIAP-1 LOROP camera system. That aircraft was designed to fly a four minute "photo run" cruising at Mach 2.4 while flying at 78.000 feet. The proposal did not progress beyond the mock-up stage because USAF felt it as a threat to the F-15.
The RF-4X, not the F-4X, is the subject of attached profile on on dan_inbox's post.

F-4E(S) Shablool

McDD F-4E Kurnass deliveries to Israel AF from September 1969 was a serious headache for Egypt's security and President Nasser received help from the USSR in form of an ADF divission which was deployed in early 1970. From that moment, F-4E impunity was lost but also Israeli LOROP operations were neutralized.
A reccon aircraft capable to flight to avoid the SAM was to be sought:

Mirage IV was no longer viable for political reasons
SR-71 and U-2 were not approved for export.
RB-57F with GD HIAC-1 camera was approved for export but, at the end, was denied too.

The GD HIAC-1 fitted on the GD G-139 pod could be carried on the RF-4C centreline station but aircraft performance was downgraded enough to be out of Israeli needs. Israeli AF then suggested the RF-4X which was then on development but the US was reluctant to export such a high performance aircraft. A compromise was adopted in the form of the F-4E(S) for Special.
Project Peace Jack covered the modification of 3 Israeli AF F-4E Kurnass into F-4E(S). The Shablool reccon birds changed its "fighter noses" with the RF-4X "photo nose" an entered service during 1976.


Source: International Air Power Review Volume 19. There is an excellent article from Shlomo Aloni about F-4E(S) Shablool that I strongly recommend. (Well I strongly recommend an International Air Power Review suscription because it's one of the highest quality aviation magazines of the World :-*)

I also took some bits of info form Aerofax Datagraph 6 "F-15" by Dennis R Jenkins.

Regards,
Antonio
 

Archibald

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I just agree with that... confusion now rectified.
F-4X (mach 3.2 fighter)
RF-4X (recon variant with HIAC-1 LOROP camera)
F-4E(S) (standard RF-4 with the LOROP camera)

;)
 

Tophe

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Google/pictures, asking F-4X Phantom gave me this: a twin-fin (almost twin-tail) F-4... Nice! What-if fantasy?

from http://i1.tinypic.com/skxiti.jpg
 

Antonio

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I just agree with that... confusion now rectified.
F-4X (mach 3.2 fighter)
RF-4X (recon variant with HIAC-1 LOROP camera)
F-4E(S) (standard RF-4 with the LOROP camera)
Sorry Archie, just a little "re-rectification" ;)

F-4E(S) (standard F-4E LOROP camera but not RF-4E)

Nice whatif art Thope, the artist possibly used F-4X designation to reflect a very modified aircraft.

May be he was inspired by the real F-15XX to photoshop its Phantom pic

http://www.secretprojects.co.uk/forum/index.php/topic,2.0.html


About the real F-4X: I think a profile could be easy produced replacing the photo nose from dan_inbox's RF-4X posted profile with an F-4E fighter nose. According to Mr Aloni's article the F-4X evolved from the F-4E variant. Any of our artists would produce an F-4X in operational colours (USAF or even IDF/AF). ::)
 

Antonio

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I think a profile could be easy produced replacing the photo nose from dan_inbox's RF-4X posted profile with an F-4E fighter nose.
And so I done. A toke the F-4E nose from Enzo Angelucci's "The American Fighter" profile and here it is!

An F-4X :eek:

Next step could be the addition of a couple of Seekbat AAM under the wings 8)
http://www.designation-systems.net/dusrm/m-97.html

There is no info at "The American Fighter" about the F-4X but another interceptor project it's listed but not described

F-4T: more advanced version, never built, of the F-4E for air defense and interception and interception, armed with six missiles
It was a low cost IMI proposal? ???

Please help
 

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Archibald

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I think Joe Baugher also mention a Phantom with Phoenix... it was proposed after the failure of the F-111B.
 

elmayerle

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F-4T was, at one point, a single-seat version of the F-4E that was proposed to the Luftwaffe (they eventually bought the F-4F instead).
 

Antonio

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Found this
F-4L - Designation applied to several proposals for an advanced version, including Model 98FOA with RR Spey turbofan engines and AIM-54 Phoenix missiles.
here:

http://mgrcentral.com/a/Top/News/Weather/Marine/295045/F-4+Phantom+II+variants.html
 

Iranian F-14A

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At one time,didn't McDonnell Douglas pitch a single seat F-4 as a low cost export fighter? IIRC,a version of the Crusader was also offered,but in the end,the F-5 series was the winner.
 

elmayerle

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Iranian F-14A said:
At one time,didn't McDonnell Douglas pitch a single seat F-4 as a low cost export fighter? IIRC,a version of the Crusader was also offered,but in the end,the F-5 series was the winner.
Another version of the F-4T.

I've also seen a McAir document that was in Jay Miller's possession that listed the F-4L as a Spey-powered equivalent of the F-4E.
 

Antonio

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AIM-54 Phoenix capable means AN/AWG-9 radar?
 

Antonio

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At one time,didn't McDonnell Douglas pitch a single seat F-4 as a low cost export fighter? IIRC,a version of the Crusader was also offered,but in the end,the F-5 series was the winner.
It was the IFA (International Fighter Aircraft program from 1970 for US Allies. Potential customers: South Vietnam, South Korea and Taiwan). McDD submited a "less complex and lightened version of the F-4E" Quoted from: F-16 Aerograph I by Jay Miller (No references if it was a single seater).
The winner design was the Northrop F-5-21 later designated as F-5E.
 

Rosdivan

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Apologies for bumping this, but structurally, how was the Phantom supposed to take the addition of another 40,000 pounds worth of weight in the water?
 

r16

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ı believe the water capacity was for 5000 pounds or so , enough for 10 minutes of flight .
 

Deadtroopers

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r16, you have confused the liquid capacity of the slipper tanks with the wight of their contents. 5000 gals US of water = 41,750 lbs. The capacity is the same in all the sources I have seen. Comparing the photographs and three views of the F4X with those of the proposed Boeing upgrade with 1100 gal US conformal tank, I find it hard to believe the sources for the capacity of these proposed slipper tanks. By eye they look to have about half the quoted capacity if that. Perhaps someone can clear up the disconnect here. This bird would have been lifting out on the far side of a hundred thousand pounds all up with that weight of water and the additions to equipment and airframe. I am not surprised it didn't make to a flight article. On the information available it looks rather unworkable. Cheers
 

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All the sources I have reviewed have reported 5,000 US gallons of water/methanol (40,000 lbs - Not!). The correction to this should read 5,000 pounds. Since 1 gal water weighs 8 pounds, each conformal tank could contain about 312 US gal (equivalent to splitting the 600 gal center-line tank into two sections and mounting to each side of the spline). To generate additional 9,000 lbf (150%) per engine, one gallon of water per second must be injected into the engine and accelerated to 1500 MPH via after-burner. Therefore, 625 gal of water being delivered at 2 gal per sec = 312 sec. or about 5 minutes. TOW should be about 55,000 lbs (600 gal centerline, two 370 gal pylon tanks and two 312 gal conformal water tanks). All but the conformal water tanks would need to be jettisoned before the high-speed dash. Reference image in reply #17 and picture F-4X 03 in reply #33. Preferably, a low-drag 1100 gal conformal belly fuel tank (Boeing proposal) would not require jettisoning. Bingo fuel after the proposed recon profile should be about 3,500 lbs. 'Hope this clarifies and adds to existing info.
- Phantom-Phlyer
 

taildragger

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pometablava said:
At one time,didn't McDonnell Douglas pitch a single seat F-4 as a low cost export fighter? IIRC,a version of the Crusader was also offered,but in the end,the F-5 series was the winner.
It was the IFA (International Fighter Aircraft program from 1970 for US Allies. Potential customers: South Vietnam, South Korea and Taiwan). McDD submited a "less complex and lightened version of the F-4E" Quoted from: F-16 Aerograph I by Jay Miller (No references if it was a single seater).
The winner design was the Northrop F-5-21 later designated as F-5E.
I believe the West Germans also ordered a single seat version as the F-4F, the purpose of which was lowered acquisition and operating costs. It maintained the same shape as other Phantoms but had an equipment bay in place of the rear cockpit with the transparency replaced by a metal fairing. Apparently the savings weren't judged worth the reduced capabilities and the airplanes were produced with 2 crewstations and rear transparancies. I recall seeing a McD&D ad depicting the single-seat F-4F.
 

shockonlip

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Phantom-Phlyer said:
All the sources I have reviewed have reported 5,000 US gal. A correction to this info should read 5,000 pounds. Since water weighs 8 pounds per gal, the two conformal tanks would each contain 312 US gal (equivalent to splitting the 600 gal center-line tank into two sections and mounting to each side of the spline). To acheive 9,000 pounds of additional thrust per engine (150%), 4 pounds of water per second has to be injected and accelerated to 1500 MPH via the after-burner. Therefore, 5,000 lbs water / 8 lbs per sec = 625 sec. or roughly 10 minutes at 52,000 lbs thrust. For Take-Off the RF-4X could weigh up to 60,000 lbs (600 gal centerline, two 370 gal pylon tanks and two 312 gal conformal water tanks). All but the conformal tanks would need to be jettisoned before the high-speed dash. Return to base after the proposed recon profile should leave about 3,500 lbs of fuel for landing. 'Hope this clarifies and adds to existing info.
- Phantom-Phlyer
A first post and a very interesting one at that !
Welcome Phantom-Phlyer!
We share similar interests !

Question, on your per engine thrust calculations.
I assume that your water flow rate is in lb-mass
and not lb-weight.

Is the water tank calculation also in lb-mass ?

Welcome again!

Quite an interesting post!

Enjoyed it very much.
 

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taildragger said:
pometablava said:
At one time,didn't McDonnell Douglas pitch a single seat F-4 as a low cost export fighter? IIRC,a version of the Crusader was also offered,but in the end,the F-5 series was the winner.
It was the IFA (International Fighter Aircraft program from 1970 for US Allies. Potential customers: South Vietnam, South Korea and Taiwan). McDD submited a "less complex and lightened version of the F-4E" Quoted from: F-16 Aerograph I by Jay Miller (No references if it was a single seater).
The winner design was the Northrop F-5-21 later designated as F-5E.
I believe the West Germans also ordered a single seat version as the F-4F, the purpose of which was lowered acquisition and operating costs. It maintained the same shape as other Phantoms but had an equipment bay in place of the rear cockpit with the transparency replaced by a metal fairing. Apparently the savings weren't judged worth the reduced capabilities and the airplanes were produced with 2 crewstations and rear transparancies. I recall seeing a McD&D ad depicting the single-seat F-4F.
Interestingly, as originally specified for Germany the F-4F had no capability to use radar guided missiles. Finally, they looked all the Phantoms they had and said, "Are we crazy??!!??", and upgraded the a/c to use them.
 

Arjen

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Israeli F-4E 69-7576 modified by General Dynamics, December 1974 as a mockup for the RF-4X. This aircraft was later modified to one of three F-4E(S) minus PCC, but with a HIAC-1 LOROP camera in the nose.
 

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fightingirish

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Ference said:
I can provide some text (still having problems finding pics):

The F-4X and RF-4X were proposals for advanced F-4E derivatives designed by General Dynamics to carry the HIAC-1 long focal length camera as part of Project Peace Jack. This project was a joint Israel-USAF study for an advanced photo-reconnaissance aircraft capable of Mach 3+ performance.

The HIAC-1 camera was an advanced high-altitude reconnaissance camera that had a focal length of 66 inches which offered unparalled resolution at extreme ranges. The HIAC-1 camera was originally so large and heavy that it could only be carried by the Martin/General Dynamics RB-57F. However, later versions were sufficiently slimmed down so that they could potentially be carried by smaller aircraft such as the F-4 Phantom.

Israel had always wanted the HIAC-1 camera for its own use in keeping track of its Arab neighbors, but its requests had always been turned down. However, in 1971, US attitudes towards export of the HIAC-1 camera changed and approval was given for the development of a pod (designated G-139) which could be carried on the belly of the Phantom. The prototype G-139 pod was over 22 feet long and weighed over 4000 pounds, and was first tested on an RF-4C in October of 1971.

Unfortunately, the G-139 was still so large and bulky that the performance of the Phantom when it was carrying the pod was unacceptably poor. The Peace Jack project originated in an attempt to improve the performance of the Phantom when carrying this camera. Both the USAF and the government of Israel contributed funds for the project.

Rather than trying to slim down the reconnaissance pod, the original goal of the General Dynamics team was to improve the performance of the Phantom that was carrying it. The improved performance was to be obtained by using water injection for pre-compressor cooling, which would provided increased engine thrust at high altitudes. A similar system had been used successfully in the past in various F-4 record attempts. The water was to be contained in a pair of gigantic 2500-gallon tanks which were to be attached conformally to the intersection joints of the fuselage spine and the engine nacelles. The water injection system promised to give a 150 percent increase in engine thrust at altitude. In order to accommodate the increased engine thrust that would now be available, new air intakes had to be designed. The area of the intakes was to be made much larger and they were to contain a sophisticated system of internal cowls, splitter plates, vortex generators and bleeds. With the new intakes and the water injection system, it was anticipated that maximum speeds of up to Mach 3.2 and cruising speeds of up to Mach 2.7 could be attained. The project came to be known as the F-4X, although this was not an official USAF designation.

Israel was clearly very interested in the F-4X, as it promised a a performance which would approach that of the USAF's SR-71. This would enable it to fly unimpeded anywhere it wanted to. However, the advanced performance of the F-4X clearly made it a possible candidate for a new interceptor. Consequently, the US State Department became more than a little worried about the export of such advanced technology overseas, since it promised to give Israel a potential interceptor which was more capable than anything currently in the US arsenal, one which might one day pose a threat to the SR-71. In addition, the Air Force was itself rather nervous about the F-4X project, since it might threaten to divert support away from the F-15 program which was just then getting underway. As a result, the State Department decided to disallow export of this technology to Israel.

This ordinarily would have been the end of the game. However, in the meantime, Israel had expressed concern about the amount of aerodynamic drag produced by the pod carrying the camera. In response to these concerns, General Dynamics decided to relocate the HIAC-1 camera to the nose, displacing the AN/APQ-120 radar. The project was redesignated RF-4X. The removal of the interceptor capability seems to have reassured the State Department, and Israel was once again allowed back into the Peace Jack program.

An ex-IDFAF F-4E (USAF serial 69-7576) was delivered to General Dynamics in December of 1974 to act as a mockup for the RF-4X. The nose was recontoured on the starboard side only, and a paper-mache coolant tank was fitted to one side of the upper fuselage. New intakes with revised variable ramps were fitted. However, in the meantime, the Air Force began to have second thoughts about the project, still fearful of the impact of the RF-4X on the F-15 project and nervous about the safety and reliability of pre-compressor cooling. The USAF withdrew from the project shortly thereafter, forcing Israel to go it alone. By itself, Israel could not afford to continue the project, and the RF-4X program quietly died.

The idea for the nose-mounted HIAC-1 camera was later revived to form the basis of the F-4E(S), which was first applied to F-4E 69-7576.
MinMiester said:
Pictures and information courtesy of Tom:

Initially it was the USAF which asked for the capability of carrying HIAC-1 equipment on Phantoms. Some RF-4Cs stationed in Korea were thus equipped with pods with that equipment; but such pods degraded performances considerably.

Thus the Israelis asked for three F-4Es from the Peace Jack programme to be converted to F-4E(Special/S) by General Dynamics in that sense, that the HIAC-1 equipment would be placed in the specially redesigned nose. Such version was initially designated RF-4X, and the USAF was also interested in acquiring some, but it pulled back from the project in 1975. The flight testing of the RF-4X was started on 20 December 1975, by which time the type
was redesignated back to F-4E(S), as - except the nose - nothing else was specialized on it any more.

In Israeli service from early 1976 (at least the first example, with the serial 69-7576; remaining examples - one of which was 69-7570 - followed in 1978), these three F-4E(S) were equipped with pylons for carriage of Sidewinders in the forward starboard Sparrow well, ALQ-109 ECM-pods, ELTA's IFF and UHF-radios. As it seems, all three have got markings of the 119 Sqn, and standard camo patterns, as well as "radomes" painted in black. Their
Israeli serials were 492, 498 and 499. Two examples carried also kill markings: one from the war in 1973, when it downed one Egyptian MiG-21, and another (498) from a recce operation over Iraq, in early 1981, when it caused a pursuing Iraqi MiG-21 to crash due to fuel starvation. However, it seems that meanwhile also one F-4E(S) was lost, most probably in July 1982, over Lebanon.

However, Israeli F-4E(S) have nothing to do with the super-fast F-4X any more, although I'm sure the IDF-AF could make some good use of very fast recce planes during the '80s....

I attached here three pics, showing the development of that version.
Picture F-4X 01
A "standard" F-4E(S), equipped with the nose, redesigned to carry a HIAC-1 LOROP equipment (BTW, Israelis have also developed at least two indigenous containers which could carry such equipment; such containers would be mounted under the centreline of their standard F-4Es).
Picture F-4X 02
The same plane with added cardboard fuel tank over engine nacelles.
Picture F-4X 03
The further development, including cardboard intakes, which would made this plane capable of reaching speeds over Mach 2.7.
MinMiester
Source: Key Publishing Ltd Aviation Forums > Modern Military Aviation > F-4X pictures?
Edit:
Original picture source is unknown so far. The attached pictures will be deleted, if they violate forum rules and copyright.
Edit 2:
Original picture source might be the book "McDonnell F-4 Phantom: Spirit in the Skies" by Jon Lake & David Donald, Aerospace Publishing / Airtime Publishing; Enlarged 2nd edition (October 1, 2002) [Amazon.com] ???
 

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shockonlip

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Thanks VERY much fightingirish !!

Picture source?

Are there more, especially of the modified inlet and side, like F-4X 03?

WOW!

I'm very intrigued by this PCC stuff!
 

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shockonlip said:
Phantom-Phlyer said:
All the sources I have reviewed have reported 5,000 US gal. A correction to this info should read 5,000 pounds. Since water weighs 8 pounds per gal, the two conformal tanks would each contain 312 US gal (equivalent to splitting the 600 gal center-line tank into two sections and mounting to each side of the spline). To acheive 9,000 pounds of additional thrust per engine (150%), 4 pounds of water per second has to be injected and accelerated to 1500 MPH via the after-burner. Therefore, 5,000 lbs water / 8 lbs per sec = 625 sec. or roughly 10 minutes at 52,000 lbs thrust. For Take-Off the RF-4X could weigh up to 60,000 lbs (600 gal centerline, two 370 gal pylon tanks and two 312 gal conformal water tanks). All but the conformal tanks would need to be jettisoned before the high-speed dash. Return to base after the proposed recon profile should leave about 3,500 lbs of fuel for landing. 'Hope this clarifies and adds to existing info.
- Phantom-Phlyer
A first post and a very interesting one at that !
Welcome Phantom-Phlyer!
We share similar interests !

Question, on your per engine thrust calculations.
I assume that your water flow rate is in lb-mass
and not lb-weight.

Is the water tank calculation also in lb-mass ?

Welcome again!

Quite an interesting post!

Enjoyed it very much.
Thanks for your kind words and feedback - I have since modified my original post to correct another source in regards to 9,000 lbf per engine. My calculations indicate this should be the total additional thrust if 5,000 lbs for PCC. Results compared favorably to the F-105D PCC operation for take-off boost of 2,000 lbf. It would require 1 gal per second of water injection to generate 9,000 lbf from one engine and this would provide PCC for only five minutes.
 

LowObservable

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I thought that the main idea of PCC (which had been demoed in the early F4H-1F record flights and adopted in the MiG-25 - I wonder if anyone knew that?) was that the evaporation dropped the air temp at the compressor face and hence allowed the engine to run at higher throttle settings without exceeding temp limits at the back of the compressor.

Wouldn't it be cool to find someone very rich to build an F-4X, just for s***ts and giggles....
 

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LowObservable said:
I thought that the main idea of PCC (which had been demoed in the early F4H-1F record flights and adopted in the MiG-25 - I wonder if anyone knew that?) was that the evaporation dropped the air temp at the compressor face and hence allowed the engine to run at higher throttle settings without exceeding temp limits at the back of the compressor.

Wouldn't it be cool to find someone very rich to build an F-4X, just for s***ts and giggles....

There were several reasons for it. 1. Cool the air, which lowers the temperature obviously, but it also increases air density (which means more power at the back end). 2. The water adds mass to the airstream (and since F=ma. . .).

Skyburner used PCC and as the guy flying the record said (paraphrased), "the aircraft was still accelerating but I didn't know what would happen if the water ran out at those speeds". As for the Mig-25 that is how they were able to get that 123,000ft zoom altitude. It's discussed in one of Airtime Publishing's books that covers the Mig-25 IIRC. I didn't know it was in all service aircraft though. They were also planning to use it for RASCAL. According to a P&W engineer they could get sea-level performance out of an F100 at 100,000ft with it according to AW&ST.
 

shockonlip

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sferrin is correct.

I would also point out LO, that a simple little thing like
cooling the air going into the compressor has major impact
on the compression process.

If you look at a compressor performance chart. It has
Compressor Mass Flow Rate on the x-axis and Pressure Ratio
on the y-axis. Going across the chart, rising at about
a 45deg. angle is the compressor operating line. At some
point on that line (say half way up) you are operating at
100% RPM, you're normal operating point.

At that 100% RPM operating point, you start water injection
upstream of the compressor.

Due to the cooling effect mentioned by sferrin,
the operating temperature of the compressor is reduced.
This does some neat things to the compression process:
The corrected RPM of the engine goes up (corrected
RPM = N/sqrt(theta); where N = engine RPM and theta is
essentially the temp (which is reduced due to PCC). Since
the denominator is reduced, corrected RPM goes up, which
moves the compressor operating point to the right on the
x-axis, to a higher Compressor Mass Flow Rate.

And since the operating line is angled at 45 deg. upward,
and we now moved the operating point to the right, we also
go up the operating line to a higher y-axis value, or a
higher Pressure Ratio!!

So PCC cools the compressor air, actually due to water
evaporation, and raises the pressure ratio and mass flow
rate. So the turbine and nozzle (the backend), as sferrin
mentioned, is actually passing more mass flow and therefore
more thrust.

There is a danger of compressor stall if we cause to fast
a temperature reduction without enough additional mass flow,
because then the compressor operating line will angle up
and cross the compressor stall line (which runs above the
operating line).

But if the PCC temperature reduction and mass flow is
correct for this engine, then the operating line, as it rises
due to PCC, will parallel the stall line, and no stall will
happen.

There is also the possibility of additives to the water
tank to preclude freezing, like alcohol, which helps the water
also evaporate in the compressor more quickly.

The idea is that you want to employ PCC until the air at
the compressor discharge is saturated. So say your in a fast
airplane and Mach number is increasing (helped by PCC too).
So, to achieve this, as the air into the compressor becomes
hotter (due to inlet compression at higher Mach), you increase
the PCC augmentation. So the possible PCC augmented thrust ratio
goes up with higher Mach number.

To give an idea of possible thrust augmentation multipliers,
on a chart I have at home in one of my propulsion books,
it shows PCC thrust augmentation of 2.6X at Mach 2 with
injected water-air ratio of around .115 (NACA TN 2083 - 1950).

So this is cool stuff (pun intended!)

>Wouldn't it be cool to find someone very rich to build an F-4X,
>just for s***ts and giggles....
We think alike!!
 
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