The AX Competition (rivals and development of the Fairchild A-10 Thunderbolt II)

[RayOrtensie]

On18 December 1970, Robert Channing Seamans Jr., Secretary of the Air Force, announced the selection of Fairchild Hiller Corporation and the Northrop Corporation out of six companies – Fairchild Hiller Corporation, the Boeing Company, Northrop Corporation, Cessna Aircraft Company, General Dynamics Corporation, and Lockheed Aircraft Corporation – as the contractors for the competitive prototype phrase of the A-X Program. Roughly a year-and-a-half later, two aircraft took their first flight at the Air Force Flight Test Center, Edwards AFB, California, in competitive flight evaluation testing when Fairchild’s A-10 took its first flight on 10 May 1972 and Northrop’s A-9 took its first flight twenty days later.

In the 1970s, Headquarters Air Force Systems Command History Office wrote a three-part study on the development to production of the Fairchild-Hiller A-10 Warthog. This volume, “A Birth of a Hog,” is the compiled three studies along with the original photographs and additional historical photographs to add to the historical context of the studies.

Link to PDF: https://drive.google.com/file/d/1ryVH056qEskPkgDZmTWC4zB2FUcbtxQT/view?usp=sharing

 

[overscan (PaulMM)]

On18 December 1970, Robert Channing Seamans Jr., Secretary of the Air Force, announced the selection of Fairchild Hiller Corporation and the Northrop Corporation out of six companies – Fairchild Hiller Corporation, the Boeing Company, Northrop Corporation, Cessna Aircraft Company, General Dynamics Corporation, and Lockheed Aircraft Corporation – as the contractors for the competitive prototype phrase of the A-X Program. Roughly a year-and-a-half later, two aircraft took their first flight at the Air Force Flight Test Center, Edwards AFB, California, in competitive flight evaluation testing when Fairchild’s A-10 took its first flight on 10 May 1972 and Northrop’s A-9 took its first flight twenty days later.

In the 1970s, Headquarters Air Force Systems Command History Office wrote a three-part study on the development to production of the Fairchild-Hiller A-10 Warthog. This volume, “A Birth of a Hog,” is the compiled three studies along with the original photographs and additional historical photographs to add to the historical context of the studies.

Link to PDF: https://drive.google.com/file/d/1ryVH056qEskPkgDZmTWC4zB2FUcbtxQT/view?usp=sharing

That's a great primary source, thanks for sharing it! I added the PDF to the original post.

 

[overscan (PaulMM)]

From the document posted above - early NAA A-X design. You can see A-10 here.

https://www.secretprojects.co.uk/threads/the-ax-competition-rivals-and-development-of-the-fairchild-a-10-thunderbolt-ii.2615/page-5#post-524726

 

[overscan (PaulMM)]

Early Airforce AX concepts 1967


and in 1968 they used Northrop and McDonnell designs as representative


Source: https://www.secretprojects.co.uk/th...d-a-10-thunderbolt-ii.2615/page-5#post-524726

 

[overscan (PaulMM)]

Source:

A-10 Thunderbolt II (Warthog) Systems Engineering Case Study

AFIT / Resource not found

Original URL was dead. Here's a copy.

 

[RayOrtensie]

On18 December 1970, Robert Channing Seamans Jr., Secretary of the Air Force, announced the selection of Fairchild Hiller Corporation and the Northrop Corporation out of six companies – Fairchild Hiller Corporation, the Boeing Company, Northrop Corporation, Cessna Aircraft Company, General Dynamics Corporation, and Lockheed Aircraft Corporation – as the contractors for the competitive prototype phrase of the A-X Program. Roughly a year-and-a-half later, two aircraft took their first flight at the Air Force Flight Test Center, Edwards AFB, California, in competitive flight evaluation testing when Fairchild’s A-10 took its first flight on 10 May 1972 and Northrop’s A-9 took its first flight twenty days later.

In the 1970s, Headquarters Air Force Systems Command History Office wrote a three-part study on the development to production of the Fairchild-Hiller A-10 Warthog. This volume, “A Birth of a Hog,” is the compiled three studies along with the original photographs and additional historical photographs to add to the historical context of the studies.

Link to PDF: https://drive.google.com/file/d/1ryVH056qEskPkgDZmTWC4zB2FUcbtxQT/view?usp=sharing

That's a great primary source, thanks for sharing it! I added the PDF to the original post.

Thanks, Paul!

 

[acegeek9992]

A cleaned-up version of pictures seen earlier in this topic:

1°) The first Convair design reminds me of the much earlier OS-117 proposal for the Navy.
2°) No mention of the Vought V-502 in the report. It might have been dropped at an early stage in the competition.

Enjoy!

Just think of how complex the whole synchronization gear for the Convair A-X proposal would be!

 

[acegeek9992]

These were found on the internet. No confirmation of authenticity...

During the summer of 1967, tests were conducted in the Langley 7- by 10-Foot High-Speed Tunnel on designs submitted by Grumman, Northrop, McDonnell, and General Dynamics. In 1970, the requirements for the A-X mission were changed, and the Air Force issued a new request for proposals (RFP). Six companies responded to the RFP

http://oea.larc.nasa.gov/PAIS/Partners/A_10.html

The Grumman design must be from the 1967 period, as they did not respond to the 1970 RFP

Was there any designation to their proposal?

 

[acegeek9992]

Better versions of the Lockheed AX project drawings (L-1400)

Both look like someone decided to take a U-2 and kit it out for low-altitude ground attack

 

[Grey Havoc]

Early A-10 - The Unwanted Blog (2)

An artists rendering of the Republic A-10 circa 1971. This is very nearly the final design, but it differs in details; the cockpit […]

unwantedblog.com

 

[overscan (PaulMM)]

Higher res copy via https://twitter.com/tempest_books

 

[overscan (PaulMM)]

Good Day All -

Found these two sketches in the Robert Kemp Collection on the SDASM Flickr which seem to be AX designs.

Enjoy the Day! Mark

Are we sure these two sketches are legit? In both the ejection seat triangles are drawn upside down.

The sketches are AX trade studies where Convair made a turboprop and turbofan design to show the Air Force a turbofan design could be competitive for the AX mission.




Source: Robert E. Bradley, Convair Advanced Designs II.

 

[hesham]

From Close Air Support,Hearing 1971.

 

[Dew]

Higher res copy via https://twitter.com/tempest_books

In colour from SDASM

https://flic.kr/p/2oX7xXG

Also:

https://flic.kr/p/2pChZA9

 

[Scott Kenny]

Found via the French version of Wikipedia:

"General Electric GAU-8/A displayed next to a Volkswagen Beetle for size comparison". [IMAGE CREDIT: USAF/ Wikimedia Commons]​

My favorite picture involving the A-10.

I'd be such a jerk about it, too. Have all the engineers involved in a room and then do a big dramatic reveal of this scene. "Your mission, gentlemen, is to make this gun fly."

Thanks for sharing, even if not for the first time.

One question on the Convair AX-1 proposal...how they heck did they envision syncronizing a 30mm Gatling gun to fire through the prop? I have never heard of an externally-powered gun being syncronized in that way. The only system I can imagine is electric ignition and the gun would just spit out, unfired, the rounds that would have hit the prop, which seems very wasteful given the price of depleted uranium.

DU wasn't all that expensive then, since it is a waste product from producing nuclear weapons and refining fuel for reactors.

(Source: https://aviation.stackexchange.com/...7-stuka-not-replaced-with-a-more-powerful-one)

As a huge fan of the AX/A-10 and it's role, this is the first time I've heard of Hans-Ulrich Rudel participation in the AX program.


Regards
Pioneer

I knew everyone involved with the program was ordered to read Rudel's memoirs. Wasn't sure the Old Man was involved directly.

 

[Pioneer]

I knew everyone involved with the program was ordered to read Rudel's memoirs. Wasn't sure the Old Man was involved directly.

Ok, good and valid point my dear Scott Kenny!
So you've opened a can of worms, which realistically, I should have researched more thoroughly, now that you've said it......

As such, I found the following:

"But [Pierre] Sprey knew the importance of CAS, had some big ideas on how to do it best and had written scholarly papers on the subject. He’d studied the Stuka, and one of his heroes was Hans-Ulrich Rudel, the ultimate ground-attack pilot (with more than 2,000 vehicles, trains, ships, artillery pieces, bridges, aircraft and landing craft destroyed, including 519 tanks). Sprey is said to have required every member of the A-10 design team to read Rudel’s autobiography, Stuka Pilot."

(Source: https://www.historynet.com/a10-warthog-beloved-military-plane-origins/)

Regards
Pioneer

 

[overscan (PaulMM)]

Agreed. The aircraft's general lines and proportions all converge toward the Convair Model 70. I can't argue with that! You'll have to admit though that the engine installation is extremely different from the various images we have of that design. Hence my (false) assumption that it might have been Cessna (I realize of course that the latter's lines are different).

Final proof it was a Convair design:

https://flic.kr/p/2pCbTtV

View: https://www.flickr.com/photos/sdasmarchives/53574416367/

 

[DesScorp]

On18 December 1970, Robert Channing Seamans Jr., Secretary of the Air Force, announced the selection of Fairchild Hiller Corporation and the Northrop Corporation out of six companies – Fairchild Hiller Corporation, the Boeing Company, Northrop Corporation, Cessna Aircraft Company, General Dynamics Corporation, and Lockheed Aircraft Corporation – as the contractors for the competitive prototype phrase of the A-X Program. Roughly a year-and-a-half later, two aircraft took their first flight at the Air Force Flight Test Center, Edwards AFB, California, in competitive flight evaluation testing when Fairchild’s A-10 took its first flight on 10 May 1972 and Northrop’s A-9 took its first flight twenty days later.

In the 1970s, Headquarters Air Force Systems Command History Office wrote a three-part study on the development to production of the Fairchild-Hiller A-10 Warthog. This volume, “A Birth of a Hog,” is the compiled three studies along with the original photographs and additional historical photographs to add to the historical context of the studies.

Link to PDF: https://drive.google.com/file/d/1ryVH056qEskPkgDZmTWC4zB2FUcbtxQT/view?usp=sharing

Thank you for posting this. It was great reading, with lots of background info (the cannon competition section was a nice touch), and I read it "cover to cover" over the last two days.

 

[overscan (PaulMM)]

Thank you for posting this. It was great reading, with lots of background info (the cannon competition section was a nice touch), and I read it "cover to cover" over the last two days.

Seconded - a really great document.

 

[fightingirish]

More pictures showing two wooden models of the Convair Model 100 Super COIN aka "A-8A" were uploaded at SDASM flickr Archives today.

https://flic.kr/p/2pHs1P3

View: https://flic.kr/p/2pHs1P3

https://flic.kr/p/2pHsy79

View: https://flic.kr/p/2pHsy79

https://flic.kr/p/2pHrnmw

View: https://flic.kr/p/2pHrnmw

https://flic.kr/p/2pHqh2J

View: https://flic.kr/p/2pHqh2J

https://flic.kr/p/2pHkHcp

View: https://flic.kr/p/2pHkHcp

https://flic.kr/p/2pHs1PJ

View: https://flic.kr/p/2pHs1PJ

https://flic.kr/p/2pHsy7V

View: https://flic.kr/p/2pHsy7V

https://flic.kr/p/2pHqh3L

View: https://flic.kr/p/2pHqh3L

https://flic.kr/p/2pHs1R7

View: https://flic.kr/p/2pHs1R7

 

[TomS]

DU wasn't all that expensive then, since it is a waste product from producing nuclear weapons and refining fuel for reactors.

We are sort of picking over a 12-year-old comment, but the GAU-8 feed mechanism did take spent cases and run them back into the back end of the drum rather than dumping them overboard. Probably it would have done the same with rounds that were not fired as a result of synchronization. After a flight, it would be easy enough to sort them out and reload them.

 

[Scott Kenny]

We are sort of picking over a 12-year-old comment, but the GAU-8 feed mechanism did take spent cases and run them back into the back end of the drum rather than dumping them overboard. Probably it would have done the same with rounds that were not fired as a result of synchronization. After a flight, it would be easy enough to sort them out and reload them.

As I understand the works in there, correct. The (usually empty) cases go back into the drum for CG reasons, getting a few live rounds in there to sort out is no big deal. What I'm not clear about is what happens to those rounds that are in the gun after the pilot lets go of the trigger and before the gun spins down. I'm assuming they'd just keep going back into the drum, but it may be possible to stop the feed separate to the gun's rotation.

 

[Firefinder]

The Refeed is also done for FOD reasons.

The F104 I believe originally Ejected the things and during one of the test flights some aerodynamic basically punt the clip into the engine.

As I recall the Vulcan does have a disconnect between the feeder and the chamber that locks up when need. So you can have the gun spinning but not feeding until you nedd to fire. And the GAU8 has a similar build.

 

[TJDougherty01]

Here is the Northrup A-9A, the losing design to the A-10. I photographed this at March Airfield Museum in Riverside, Ca. This is one of two existing examples built for testing and flying against the A-10 design.

 

[andy_d]

The Refeed is also done for FOD reasons.

The F104 I believe originally Ejected the things and during one of the test flights some aerodynamic basically punt the clip into the engine.

As I recall the Vulcan does have a disconnect between the feeder and the chamber that locks up when need. So you can have the gun spinning but not feeding until you nedd to fire. And the GAU8 has a similar build.

Wasn't there also some consideration of the A-10 not dropping spent cases because it was highly likely to be operating over friendly ground forces?

 

[Scott Kenny]

Wasn't there also some consideration of the A-10 not dropping spent cases because it was highly likely to be operating over friendly ground forces?

Not that I've heard. CG and FOD purposes, yes.

Of course, as big as those cases are, you wouldn't want to have one land on you...