Vought V-526 & X-100: Fighters to 1974 VFAX requirement

overscan (PaulMM) · 12 January 2007

I believe Vought's VFAX was V-526.

It is slightly complicated by the fact there were two "VFAX" competitions, one in the mid 1960s, which turned into VFX/F-14, and then the 1973 one we are discussing here. There was a 1965 VFAX design, V-484, to the earlier competition.

overscan (PaulMM) · 2 December 2008

This is the Vought X-100, discussed in American Secret Projects, an alternative concept studied towards the VFAX specification (Originally posted by Gary Morelock/"Elider")

Stargazer · 1 December 2009

Vought seems to have done two main studies for the VFAX proposal: V-484 and V-526. To which of these would the "X-100" proposal be related?

Mark Nankivil · 2 December 2009

Greetings All -

Here is Vought's V-526 proposal. The 2 view is noted as being an "configuration study - unstable V-526" and is dated Aug-7-74. From the Vought Archives....

Enjoy the Day! Mark

Mark Nankivil · 11 December 2009

Greetings All -

A few drawings of the X-100 concept for your perusal and viewing pleasure courtesy of the Vought Archives.

Enjoy the Day! Mark

overscan (PaulMM) · 11 December 2009

Stargazer2006 said:
Vought seems to have done two main studies for the VFAX proposal: V-484 and V-526. To which of these would the "X-100" proposal be related?

You are mixing up two different VFAX competitions.

V-484 was part of the VFAX pre-VFX studies, mid/late 1960s, smaller and multimission compared to the F-14.
V-526 was design to the early/mid 1970s VFAX requirement, which was replaced by NACF when Congress decreed the Navy would have to base their aircraft on the LWF.

X-100 was an alternative concept studied in the latter timeframe, and hence was an alternative to the V-526.

Bill S · 2 October 2011

More V-526 slides from an August 1974 presentation.
Vought Historical Archives.

Slide 1 Artwork
Slide 2 Configuration
Slide 3 V-526 General Arrangement
Slide 4 V-526 Inboard Profile
Slide 5 Trade Study Configurations

Enjoy!

bill

Bill S · 2 October 2011

More V-526 slides from an August 1974 presentation.
Vought Historical Archives.

Slide 6 Stores Loading Arrangement
Slide 7 Fuel Tank Arrangement
Slide 8 V-526 and V-526A Cockpit Layout
Slide 9 V-526B and V-526D Pilot Cockpit Layout
Slide 10 V-526B and V-526D RO Cockpit Layout

Enjoy!

bill

Stargazer · 2 October 2011

Great, thanks for sharing! Which takes me back to the old question: did the General Dynamics F-16 design originate in the V-526?

Arjen · 2 October 2011

Stargazer2006 said:
did the General Dynamics F-16 design originate in the V-526?

Most definitely not. The V-526 presentation posted by Bill S are from 1974:

More V-526 slides from an August 1974 presentation.

This is from 'The Pentagon Paradox' by James P Stevenson, Naval Institute Press 1993, p.145:

The Lightweight Fighter prototype contract was awarded to General Dynamics and Northrop on April 13, 1972. General Dynamics was awarded a contract for $37,943,000 for its model 401, and Northrop received $39,878,715 for its twin-engined model P-600.

GD's model 401 became the YF-16, Northrop's P-600 became the YF-17. The contract, and by inference GD's model 401-which-led-to-the-YF-16 predates the V-526 by some years.

Related post here.

overscan (PaulMM) · 2 October 2011

Bill S said:
More V-526 slides from an August 1974 presentation.
...
Slide 5 Trade Study Configurations

Enjoy!

bill

Trade Study 460 looks similar to the "X-100".

Bill S · 29 October 2011

A couple new images just recently uncovered of the V-526 model from the 1974 time frame.
Vought Heritage Archives.

bill

Mark Nankivil · 7 August 2012

Greetings All -

During this last trip to Vought a few weeks back, I pulled a set of drawings from a V-526 folder that essentially covered the design evolution and trade offs leading to the final V-526 design. I'll attach the final V-526 designs first as reference then walk thru the design evolution from there.

Enjoy the Day! Mark

Mark Nankivil · 7 August 2012

Now the beginning of the design evolution. The initial baseline design looks to me to have a bit of F-8 DNA in the vertical fin, wing planform and position along with the inboard ailerons.

Mark Nankivil · 7 August 2012

...and more...

Mark Nankivil · 7 August 2012

...and more...

Mark Nankivil · 7 August 2012

...and more...

Mark Nankivil · 7 August 2012

Then's there's a few with designations (or none) that were in the folder that may or may not be part of the design evolution.

Mark Nankivil · 7 August 2012

In the same folder were some X-100 drawings...

Enjoy the Day! Mark

Sundog · 7 August 2012

Wow, that's a mother load of drawings! Thank you. BTW, I take it the twin engine variants had the same mass flow together as the single engine since the nose/inlet looks the same for many of them.

Stargazer · 12 August 2012

Splendid as usual. Thanks a bunch, Mark!

hesham · 12 August 2012

Mark Nankivil said:
In the same folder were some X-100 drawings...

Enjoy the Day! Mark

Looks like McDonnell-Douglas ATF design !.

Bill S · 25 April 2015

Some new images of the V-526 Concept Model and an artist concept in color of the X-100.
VAHF archives

Bill

RAP · 26 April 2015

V-526 model- very nice! Thanks!

SSgtC · 9 November 2020

Sorry for the necro, but does anyone know roughly what Vought was projecting for the V-526 performance wise? Just guessing from the info provided in the drawings and the mention of F101 engine, my WAG would be a top speed somewhere around Mach 1.7-1.9 with a combat radius of between 300 and 600 miles depending on load out and a max TO weight somewhere between 35,000 and 45,000 pounds. Does that sound about right or am I way off?

overscan (PaulMM) · 9 November 2020

I’ll check the proposal docs tonight. The V-1602 with the same engine had increased range as expected over the F401 engined version but max speed wasn’t affected.
Also note there is no concept here of not posting in old topics. I’d rather keep discussions together.

overscan (PaulMM) · 10 November 2020

So - there were 5 different versions proposed.

	V-526C	V-526	V-526A	V-526B	V-526D
Fighter Capability	CAM Fighter	CAM Fighter	Sparrow Fighter	Sparrow Fighter	Sparrow Fighter
Attack Capability	A-7 Level	A-7 Level	A-7 Level	A-7 Level	Advanced All-Weather Attack
Crew	1	1	1	2	2
Weight, FE, lb	28,540	29,420	31 ,490	31,451	32,048
FE radius NM	450	450	483	390	375
Interdiction Radius NM	1,071	1,056	1,038	932	901

Max catapult weight is 48,906lb for all versions.

I'll add more later - bedtime.

overscan (PaulMM) · 11 November 2020

CAM Fighter - 15" diameter antenna pulse-doppler radar, Sidewinders, guns, agile fire control
Sparrow Fighter - 23"x 33" antenna pulse-doppler radar, added Sparrows.
Advanced All-Weather Attack - added radar power, TWS, terrain avoidance, MTI, beacon modes

overscan (PaulMM) · 11 November 2020

Speed / altitude graph

SSgtC · 11 November 2020

overscan (PaulMM) said:
Speed / altitude graph

That's a lot more performance than I thought it would have. That's actually very impressive. How in the hell didn't this design get more consideration from the Navy?! (Partly rhetorical, I know they were ordered to use one of the two USAF LWF designs)

overscan (PaulMM) · 11 November 2020

The V-1602 with the F101 engine only had a ceiling of 44000 ft and max speed was Mach 1.95, but according to the brochure the high speed and acceleration performance were quite dependent on a modified intake with pre-compression ramp with the F101. Most likely with plain pitot intake it would be more like an F-18.

V-1602 was as close to V-526 as you could get away with while still looking like an F-16 derivative. The high aspect ratio (3.8) 30 degree wing is very Vought. Weak point of performance for F101 was ceiling and speed in intermediate thrust - it'd burn more fuel in dogfights by needing afterburner more often.

FrankM · 13 November 2020

overscan (PaulMM) said:
The V-1602 with the F101 engine only had a ceiling of 44000 ft and max speed was Mach 1.95, but according to the brochure the high speed and acceleration performance were quite dependent on a modified intake with pre-compression ramp with the F101. Most likely with plain pitot intake it would be more like an F-18.

V-1602 was as close to V-526 as you could get away with while still looking like an F-16 derivative. The high aspect ratio (3.8) 30 degree wing is very Vought. Weak point of performance for F101 was ceiling and speed in intermediate thrust - it'd burn more fuel in dogfights by needing afterburner more often.

Does the brochure by any chance tell how the F101-GE-400 was related to the B1-engine in terms of thrust, bpr and airflow?

Best regards,
Frank M.

overscan (PaulMM) · 13 November 2020

Yes.

MAX POWER, THRUST, LB	29,861
MAX POWER, SFC, LB/HR/LB	2.46
MAX POWER, AIRFLOW, LB/SEC	352
NTERMEDIATE THRUST, LB	16,150
INTERMEDIATE SFC, LB/HR/LB	0.556
BYPASS RATIO (BPR)	2.01
OVERALL COMPRESSION RATIO	26.5
TURBINE INLET TEMPERATURE (MAX), °F	2,550
DRY WEIGHT, LB	4,235
LENGTH, IN.	180.7
INLET DIAMETER, IN.	45.0
MAX DIAMETER, IN.	58.0

Configuration of stages was 2 fan / 9 compressor / 1 turbine / 2 turbines

FrankM · 13 November 2020

overscan (PaulMM) said:
Yes.

MAX POWER, THRUST, LB 29,861
MAX POWER, SFC, LB/HR/LB 2.46
MAX POWER, AIRFLOW, LB/SEC 352
NTERMEDIATE THRUST, LB 16,150
INTERMEDIATE SFC, LB/HR/LB 0.556
BYPASS RATIO (BPR) 2.01
OVERALL COMPRESSION RATIO 26.5
TURBINE INLET TEMPERATURE (MAX), °F 2,550
DRY WEIGHT, LB 4,235
LENGTH, IN. 180.7
INLET DIAMETER, IN. 45.0
MAX DIAMETER, IN. 58.0

Configuration of stages was 2 fan / 9 compressor / 1 turbine / 2 turbinesView attachment 643991

Great, many thanks!

overscan (PaulMM) · 13 November 2020

From the description it seems to be a straightforward marinized version of the B-1A's F101.

Colonial-Marine · 22 January 2024

Did the final V-526 design keep the retractable canards that were featured on some drawings and on the prior V-523?

Years later the V-1600 that General Dynamics teamed with LTV for was based on the F-16 but I wonder if any V-526 elements were included considering the general similarities between the GD and Vought designs?

R_K_M · 5 December 2024

The X-100 looks extremely close to some of Fairchild-Republics F-15 designs (c.f. https://www.secretprojects.co.uk/th...ct-rival-to-the-mcdonnell-douglas-f-15.15663/ )

Vought V-526 & X-100: Fighters to 1974 VFAX requirement

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