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

[overscan (PaulMM)]

OK, lets go back to the AX competition and the original bids submitted.

On May 8th, 1970, the AX SPO issued a request for proposal (RFP) to 12 aircraft manufacturers. Six of the 12 companies given the RFP responded with proposals: Boeing, Cessna, Fairchild Hiller, General Dynamics, Lockheed and Northrop.

Cessna's submission

Source:
A-37 in Action, Squadron-Signal

 

[overscan (PaulMM)]

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

 

[Antonio]

Overscan,

both pictures are authentic. I post it about two years ago in whatifmodelers forum in a thread about AX contenders.

You can find the Boeing Vertol AX on page 47, Le Fana de l'Aviation number 384. November 2001. The Article is Northrop YA-9, rapace resté poussin by Alexis Rocher. Excellent article, I recommend it

Grumman AX contender is a Mohawk derivative. Lark sent me a photocopy from AW&ST (I think) to take the scan for whatifmodelers forum. According to that article, it is Grumman's proposal to AX, not an unsolicited design...


Regards,

Antonio

 

[overscan (PaulMM)]

I think you misunderstood me.

There were two phases of the AX program. Stage 1 in 1967, where Grumman were involved, was primarily a COIN aircraft, Vietnam style, and so turboprop designs made sense. In 1970, the requirements were altered in such a way as to favour a turbofan powered design, and Grumman appear to have declined to bid at this time, given that their design was probably not appropriate for the new RFP.

 

[Antonio]

You're right, plase accept my apologies.

I misunderstood you because I didn't knew about that two phases. I thought it was only one. Thanks for your comment, this information gives me a new light about the AX competition....in fact I didn't understand well the disparities between the contenders.
Now I can see it clearly:

Stage I (1967):

Turboprop, a sort of heavy weight COIN

Grumman
Boeing Vertol
Cavalier Turbo-Mustang III

Stage II (May 1970):

Jet (Double flux), big gun (GAU-8 program started in November 1970)

Northrop
Lockheed
Fairchild
Cessna

 

[lark]

A-10 contenders...

6 March 1967 : first RFP send to 21 manufactureres.
Design studies for a low cost attack aircraft under designation A-X

2 May 1967 : preliminary designs studies awarded to General Dynamics , Grumman
Northrop and Mc Donnell

meanwhile need arose for an aircraft able to accurate strafing in close proximity
of friendly forced (results of Vietnam war)
and
an aircraft with a gun suitable for knocking out tanks(results of 6-day war in June 1967)

7 March 1970 - definitive RFP send to 12 manufacturers.Submission date 10.8.1970
Of the dozen manufacturers that received an A-X RFP , six responded in time.

Boeing Vertol , Cessna, Fairchild Republic Aviation division , General Dynamics
Lockheed and Northrop.
Boeing Vertol submitted the only prop. driven design and was quickly eliminated.

18 December 1970 - two contractors selected : Fairchild and Northrop.
March 1971 Nortrop and Fairchild received official designations.
YA-9 for Northrop and YA-10 for Fairchild.

So far....

Several sources .Ammong them Fairchild A-10 Thunderbolt II - Ian Allan.
The Thunderfactory- Joshua Stoff- Arms & Armour

P.S The Lockheed contenders L-1400-1 and L-1400-2
are on page 205 of "Lockheed Skunkworks" -Jay Miller . Aerofax.

Paul.

 

[Matej]

Under picture named "GrummanAX" was originally written:

Configuration based on the OV-1 Mohawk is one concept under study by Grumman Aerospace Corp. for the expected USAF AX ground-support aircraft program. The concept incorporates a new nose and cockpit section, strengthened fuselage and wings and more powerful engines, probably turboprops. The AX design would carry a lighter avionics load than current reconnaissance version of the Mohawk, but would have a greater weapons stores capacity.

Used words "expected USAF AX program" indicates, that it was before 1970 era.

 

[overscan (PaulMM)]

The USAF has issued requests for proposals for its single-seat twin-engined AX close support aircraft to 12 companies. The proposals are scheduled to be presented within 90 days of the issue of the request, and the evaluation of the competitive RFPs is expected to be completed in approximately 75 days of their receipt. Two of the contenders will then be selected for a 26-month competitive development phase. Envisaged as a relatively simple and inexpensive aircraft capable of supporting mobile army units from forward-area strips, the AX will be powered by twin turboprops with the Lycoming T55 as the primary candidate, will carry an ordnance load of the order of 8.000 lb (3 629 kg) and possess a combat radius of some 290 miles (470 km). Primary requirements include a low-cost navigation system, 30-mm rotary cannon armament, and high survivability.

Flying Review International, July 1970

 

[overscan (PaulMM)]

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

 

[Antonio]

the AX scan comes from Le Fana


[picture from initial post by Jemiba attached here for coherence]

 

[Jemiba]

"the AX scan comes from Le Fana"

Thanks, I'll add it to the description, although I found it somewhere
in the net. Is there any relàtion to the model 147 ?

 

[Antonio]

I posted it for the first time at whatifmodelers forum about 3-4 years ago. I can't remember if it is any relationship with Model 147 but I'll try to verify it later

 

[Antonio]

Dear Hesham,

I'm sorry but I can't understand very much the text but I can't find the reference to the Model 147. Can you tell me where is it?.


This is for Jemiba

Le Fana Nº384. November 2001 "Northrop YA-9" by Alexis Rocher
The Boeing AX drawing is on page 47. According to the text, there was an internal design competition: Boeing against Vertol. Vertol with Mark Kirshner's project won. That project was based on tilt wing studies after the Type 76.

I hope this info could be useful

cheers
Antonio

 

[Mark Nankivil]

I've been going thru all the older threads to see what else I may have info on or have interest in myself. This one I think I can help with as I have some drawings from Vought of a few of their proposals. I don't have any additional info other than these drawings - will try to find more on my next trip to the archives...

Enjoy the Day! Mark

 

[overscan (PaulMM)]

Interesting - seems to be from the earlier (1967) phase of the AX competition.

 

[Mark Nankivil]

That makes sense - I had thought that an A-7 variant was their entry in the final competition. I do know that A-7 was flown against the A-10 prior to committing to the A-10 full production.

Enjoy the Day! Mark

 

[overscan (PaulMM)]

Cessna's AX Proposal
CESSNA AIRCRAFT has reacted critically
to the selection of Northrop and Fairchild
Hiller (Flight, December 31) as
finalists in the AX class air support
programme for the US Air Force.
Cessna had proposed to build two
prototypes at a cost ($28.3 million) less
than the fixed price contracts awarded
to Northrop and Fairchild Hiller (respectively
$28.9 million and $41.2
million).
What the USAF has in mind is a
rugged single-seat twin-engined aircraft
with low wing loading and high
manoeuvrability, with a wide range of
speeds below 300kt and a top speed
of 400kt. The type would come into
the same category as the Cheyenne
helicopter for the Army and the
AV-8A Harrier for the Marine Corps.
A provision of $27.9 million has been
made to initiate AX development, but
it is possible that only one—or at most
two—aircraft will be decided upon for
the Services in the close air support
role, instead of one for each Service.

http://www.flightglobal.com/PDFArchive/View/1971/1971%20-%200101.html

 

[overscan (PaulMM)]

Here's some nice stuff for this topic. First, early concept formulation studies.

 

[overscan (PaulMM)]

AX submissions

 

[overscan (PaulMM)]

Source:

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

AFIT / Resource not found

 

[Skybolt]

Congrats, Paul, great find !

 

[lark]

Astounding ! Thanks a lot Paul...

 

[frank]

Neat stuff! Thanks! I especially like the GD/Convair design. It really has that Skyraider appeal. I wonder if it would've been a tri-gear or tail dragger tho. ISTR that was one point with the Skyraider, that all of its pilots were trained on Trikes & they had to learn the delicacies of the tailwheel. The McDD & Boeing AX's make me think of scaled-down AJ Savages.

Here's some nice stuff for this topic. First, early concept formulation studies.

 

[AeroFranz]

I wonder how much the "old" prop look influenced the final decision. The A-10 and A-9 are pretty much the most 'fighter-like' looking designs of the bunch.

 

[Maveric]

Do you have also the Model-Numbers of these projects...?

Thanks Maveric

 

[Orionblamblam]

I wonder if it would've been a tri-gear or tail dragger tho.

Nosegear.

 

[frank]

Thanks for that info too. Now I wonder if the 2 seater in this 2nd drawing is just because the 1st, smaller drawing is less detailed or if the 1st one is indeed a single seater. The smaller drawing canopy doesn't look long enough to be a 2 seater. Any chance of more of the detailed drawing in the future?

I wonder if it would've been a tri-gear or tail dragger tho.

Nosegear.

 

[Orionblamblam]

Thanks for that info too. Now I wonder if the 2 seater in this 2nd drawing is just because the 1st, smaller drawing is less detailed or if the 1st one is indeed a single seater.

The detailed drawing depicts an AX prototype. As Skybolt's Northrop drawing shows, there were ideas about using a two-man crew on the prototype, with a one-man operational bird. There are a number of other differences, which leads me to think that there was some time and design refinement between what I have and the report cited in the case study.

 

[frank]

I was just finally perusing the more detailed drawing & I see it shows a T-56 engine, while the description of the first 3 view lists a T-64. I wonder if it's a typo or they planned 2 different engines as well. The T-56 seems to make more sense operationally, IMHO.

Thanks for that info too. Now I wonder if the 2 seater in this 2nd drawing is just because the 1st, smaller drawing is less detailed or if the 1st one is indeed a single seater.

The detailed drawing depicts an AX prototype. As Skybolt's Northrop drawing shows, there were ideas about using a two-man crew on the prototype, with a one-man operational bird. There are a number of other differences, which leads me to think that there was some time and design refinement between what I have and the report cited in the case study.

 

[Orionblamblam]

I was just finally perusing the more detailed drawing & I see it shows a T-56 engine, while the description of the first 3 view lists a T-64. I wonder if it's a typo or they planned 2 different engines as well.

Yup.

 

[frank]

Thanks for the extra info.

I was just finally perusing the more detailed drawing & I see it shows a T-56 engine, while the description of the first 3 view lists a T-64. I wonder if it's a typo or they planned 2 different engines as well.

Yup.

 

[Pyrrhic victory]

Three ruddered A-10 wind tunnel model.

Also, was A-10's name originally "Thunder" or did they just run out of room on the building ;]?

source Long Island aviation thread @ warbird information exchange

 

[Stargazer2006]

was A-10's name originally "Thunder" or did they just run out of room on the building

Since WW II, Republic had a tradition of giving their combat aircraft names starting with "Thunder-":

- THUNDERBUG (German V-1 clone)
- THUNDERBOLT (P-47)
- THUNDERJET (P-84)
- THUNDERSTREAK (F-84F)
- THUNDERFLASH (RF-84)
- THUNDERSCREECH (F-84H)
- THUNDERCEPTOR (F-91)
- THUNDERWARRIOR (F-103)
- THUNDERCHIEF (F-105)

Following that logic, the A-10 was "a new thunder" for Republic, hence the banner on the building.

Please note that the T-46 trainer is sometimes called the "THUNDERPIGLET" but this was just an in-house monicker used for fun so as to rhyme with the real name of the aircraft: "EAGLET".

 

[frank]

It originally was & I think officially is known as "Thunderbolt II".

was A-10's name originally "Thunder" or did they just run out of room on the building

Since WW II, Republic had a tradition of giving their combat aircraft names starting with "Thunder-":

- THUNDERBUG (German V-1 clone)
- THUNDERBOLT (P-47)
- THUNDERJET (P-84)
- THUNDERSTREAK (F-84F)
- THUNDERFLASH (RF-84)
- THUNDERSCREECH (F-84H)
- THUNDERCEPTOR (F-91)
- THUNDERWARRIOR (F-103)
- THUNDERCHIEF (F-105)

Following that logic, the A-10 was "a new thunder" for Republic, hence the banner on the building.

Please note that the T-46 trainer is sometimes called the "THUNDERPIGLET" but this was just an in-house monicker used for fun so as to rhyme with the real name of the aircraft: "EAGLET".

 

[overscan (PaulMM)]

I understood "Thunderpiglet" was a reference to its similarity in planform to the A-10 "Warthog" - it was the Hog's piglet.

 

[robunos]

I thought that 'Thunderscreech' was an unofficial name, alluding to the piercing sound made by the F-84H's supersonic propeller......

cheers,
Robin.

 

[Stargazer2006]

You're probably right, just like THUNDERPIGLET, but I think the name stuck, somehow. We'd need to go back to official 1950's documents to see if the name actually appears in listings, which I'm not sure about.

 

[Mark Nankivil]

Greetings All -

Last week's visit to the Vought Archives was enjoyable and I managed to scan and copy a number of drawings and photograph a few of the display models in their possession. One of Vought's AX proposals/concepts was the L12-CAS-AX-186 which reminds of an A-4 (sort of) with over wing engine nacelles. Attached is a drawing of the aircraft and I'll post some photos of the model in their collection later. I'm still trying to work out the V# for this design.

Enjoy the Day! Mark

 

[Sundog]

Very cool, thanks Mark! I love these detailed drawings, I can't wait to see the model pics and whatever else you dug up there.

 

[Stargazer2006]

Wasn't AX an Air Force specification? Why would LTV's contender be labeled "Navy", then? Unless it was a prior design that they had initially submitted for a Navy competition and didn't bother to modify the model, maybe?