Northrop A-9 AX Design Evolution

[Stargazer]

Sorry for the above post. I hadn't noticed that the connection between the Sierra Sue and the A-9 had already been discussed in this very thread... Here's an item found online that adds to the subject:

Designed and flown by Ron Beattie and Walt Fellers, two North American Engineers who came to work for the Northrop Division. The aircraft was built by the Acme Aircraft Company (Sierradyne Inc.) Crawford and Keeney, at the Torrance Airport in late 1948. The first flight was on 23 November 1953. It was built according to Goodyear Racing Plane specifications. Although it was never entered in any races, extensive data was obtained during its many flights.

This experimental aircraft was built to investigate the advantages of a pusher propeller configuration. It has a "Y" shaped tail incorporating ruddervators on the upper fins, an unswept wing mounted midway up the fuselage, an engine mounted directly behind the cockpit, and large air scoops mounted in the forward end of both wing roots. The aircraft was used by Sierradyne in the 1960's to test and promote Northrop's and Dr Werner Pfenninger's boundary layer control concepts. Northrop used it as a flying technology demonstrator for the Air Force’s AX close-support aircraft design competition in 1972. The plane was never officially considered a Northrop aircraft.

(Bold type is mine; please note that some photos have the S-1 carrying the name "Northrop Turbo-Pusher...)

Source: Western Museum of Flight

 

[overscan (PaulMM)]

Walt Fellers was the primary designer of the Northrop pusher AX designs, which were clearly inspired by his much earlier Sierra Sue design.

 

[overscan (PaulMM)]

Better scans of Northrop AX model photos.

Wind tunnel investigation of a single-engine pusher type subsonic attack airplane model having an unswept wing of aspect ratio 6.0

NASA Technical Reports Server (NTRS)

ntrs.nasa.gov

 

[Johnbr]

Found on the loser to the A10

 

[Nico]

Yes, I apologise:
I found the designations of Northrop A-X proposals (N-308 for the turboprop pusher and N-312 and N-320 for the twin turbofan YA-9A and FH-129 and/or FRC-160 for the A-10) on the proper thread.
Now are still pending questions about and. Tizio and Williamson...
Nico

 

[Mark Nankivil]

Greetings All!

A nice model of the A9A...

http://www.ebay.com/itm/Large-Unusual-Northrop-YA-9-Model-Airplane-Plane-/320878401814?pt=LH_DefaultDomain_0&hash=item4ab5d7d916

 

[circle-5]

Side by side comparison of two Northrop factory shop models reveals the many refinements that appeared between the original A-X proposal (left, ca. November 1970) and the final A-9A configuration:

- From mid-wing to high-wing
- From flat horizontal stabilizer to pronounced dihedral
- Increase in wing chord and area
- Different air intakes, splitter plates, wingtip contours, flap tracks, engine exhausts and more...

 

[overscan (PaulMM)]

Beautiful pics of two great models. Thanks for sharing.


It's crude but this 3 view looks like the earlier mid wing model:

 

[Triton]

Northrop A-9 contractor model found on eBay.

[link no longer active]

Genuine?

 

[Triton]

Northrop A-9A model found on eBay.

Source:

http://www.ebay.com/itm/NORTHROP-A-9A-VINTAGE-AVIATION-COLLECTOR-COMPANY-DESPLAY-MODEL-/281022592776?pt=LH_DefaultDomain_0&hash=item416e407708

 

[Pioneer]

Does anyone have any links to footage of the Northrop YA-9 flying, firing cannon or dropping weapons, during the YA-10 & YA-9 flyoff / eveluation???
There has to be something out there that shows this design in flight, so as to compare too that of the YA-10 footage :-\
I've had no luck with Youtube

Regards
Pioneer

 

[The Artist]

Does anyone have any links to footage of the Northrop YA-9 flying, firing cannon or dropping weapons, during the YA-10 & YA-9 flyoff / eveluation???
There has to be something out there that shows this design in flight, so as to compare too that of the YA-10 footage :-\
I've had no luck with Youtube

Regards
Pioneer

Just a thought. See if any of the Air Force Now segments from that period have been digitized and placed on the web. We saw a lot of the Air Force Now installments on 16mm in an explorer post back in the 70s and I think there was some of what you're looking for in that series.

 

[circle-5]

Northrop YA-9A at March AFB, California, earlier today.

 

[overscan (PaulMM)]

Nice pic - and A-9 is not in too bad condition.

 

[Grey Havoc]

Nice pic - and A-9 is not in too bad condition.

Was thinking that myself.

 

[Mark Nankivil]

Good Day All -

On EPay at the moment is this nice A-9A model:

https://www.ebay.com/itm/NORTHROP-A-9A-VINTAGE-AVIATION-COLLECTOR-COMPANY-DESPLAY-MODEL-/281679698534?pt=LH_DefaultDomain_0&hash=item41956b1a66

Enjoy the Day! Mark

 

[overscan (PaulMM)]

Ron Downey has posted a copy of the Northrop A-9 Flight Manual over at

Northrop A-9A Flight Manual

Northrop A-9A Development Program Flight Manual, DPM A-9A-1. Dated 24 October 1972 Click here to download manual(59.5 Megs)

aviationarchives.blogspot.com

 

[hesham]

Ron Downey has posted a copy of the Northrop A-9 Flight Manual over at http://aviationarchives.blogspot.com/2017/06/northrop-9a-flight-manual.html

Nice find my dear Paul.

 

[overscan (PaulMM)]

And now, a copy of the A-9 Pilot's notes:

Northrop A-9A Pilot's Briefing Notes

The “Competition Sensitive” Northrop A-9A Pilot's Briefing Notes, dated May 1972. Part of my Northrop find at EAFB! Click here to downloa...

aviationarchives.blogspot.com

 

[Gruber]

Hi there first post in here but I have been lurking for a couple of years. Going back to the Northrop A-9 I have not seen any pictures of the gun cradle that is mentioned in some publications. Does anybody have any pictures of the actual gun installation?

Thanks in advance

 

[hesham]

Hi there first post in here but I have been lurking for a couple of years. Going back to the Northrop A-9 I have not seen any pictures of the gun cradle that is mentioned in some publications. Does anybody have any pictures of the actual gun installation?

Thanks in advance

I will search Gruber.

 

[Pioneer]

Stumbled across this drawing of GAU-8 installation in Northrop A-9A (Not sure if its already been posted)


Regards
Pioneer

 

[overscan (PaulMM)]

Here's a great A-9 poster, via Flateric.

 

[Foo Fighter]

The advertising types had a field day with the dictionary didn't they. Never get away with that nonsense now. Thankfully.

 

[kaiserd]

“Unbelievable invulnerability”
A literally true statement

 

[aim9xray]

This was one of a set of four theme "movie posters" that Northrop did (F-5E was also a subject) ca. 1972 - that I took as somewhat "tongue in cheek" with the Hollywood style, over the top hyperbole.

 

[TomcatViP]

A chance to get to view all of them with a single link?

 

[RAP]

...

 

[Hood]

Better than CGI any day, all it needed was Jimmy Stewart or Henry Fonda in the cockpit to finish off the effect.

 

[Sundog]

I picked up all four of those posters on Ebay last year. Now I just have to frame them. They were meant to look like comic book covers.

 

[overscan (PaulMM)]

Ron Downey has posted A-9 Technical Proposal and Source Selection documents on his blog.

Northrop A-9 Technical Proposal

A copy of the Northrop A-9 Technical Proposal. Dated 10 October 1972. Lot’s of good A-9 info here! Download here or here or here (23.4...

aviationarchives.blogspot.com

Northrop A-9 Source Selection Report

A copy of the Northrop A-9 Source Selection Competition Report, NB 72-325. Dated 20 December 1972. Download here or here or here (24.4...

aviationarchives.blogspot.com

 

[riggerrob]

Shifting from mid-wing to high-wing allowed them to shorten undercarriage and simplify wing spars
It also gave ground crew more room to work when hanging bombs or changing engines.

 

[RavenOne]

Hot on the heels after Heli Expo 2020 in Anaheim, myself and friend/colleague went on road trip and ended up at March ARB museum. Tenner to pay to get in and to explore the exhibits so here are my photos of the YA-9.

Cheers

 

[F-2]

According to this RAND report the YA-9 had direct side force control but was less effective then hoped. If heard this mentioned before. Seems to have worked the same way as on the F-2, a complex dance of flaps and rudder.

https://apps.dtic.mil/sti/pdfs/ADA117911.pdf

 

[allysonca]

You see nothing on the right............

 

[BillRo]

Sierra Sue was taken to Edwards AFB and evaluated by Air Force pilots as part of the AX evaluation according to a retired pilot I know who flew it.

 

[dan_inbox]

Thanks a lot, Allyson.
Must be nice to have enough space to host and display so many wonderful models.

 

[RipSteakface]

I obtained a full set of the MacAir 260's that had posted on the forum a long time ago. The set I had was a Transport, Transport with AWACS dome, a make it build any version set, an attack, all weather, and the 3 engine that was adapatable. I sold the entire collection and miss these the most.....

As to the Northrop AX, had this in 3 different versions in 40th scale and one 10th scale. will look for the pictures.... I have a blank I am restoring and will post as soon as it is finished. It's down the list after a shelf decided it did not want to be supportive.

This is all your collection? Color me impressed, you should do like a walkthrough or something if possible.

 

[overscan (PaulMM)]

Allyson HAD a giant collection, but sold a lot of it. Still has quite a few however.

 

[Pioneer]

View attachment 659066

According to this RAND report the YA-9 had direct side force control but was less effective then hoped. If heard this mentioned before. Seems to have worked the same way as on the F-2, a complex dance of flaps and rudder.

https://apps.dtic.mil/sti/pdfs/ADA117911.pdf

Thanks F-2, that's a lot of interesting information in only one page!

Regards
Pioneer