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Author Topic: N-156: Evolution of the Northrop F-5  (Read 43156 times)

Offline TinWing

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N-156: Evolution of the Northrop F-5
« on: April 29, 2006, 03:14:51 pm »

It was simple dropped by Northop's directive Tom Jones in favour of the far cheaper N-156 by the close of 1954.

Indeed the naval "T-tail" N-156 followed the Fang in 1954, followed by the more familiar N-156F of 1956 that lead to the F-5A.

I still haven't found an drawings or details on the original N-156. :(


Offline elmayerle

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Re: N-156: Evolution of the Northrop F-5
« Reply #1 on: April 29, 2006, 11:05:50 pm »
The earliest versions of the N-156 that have appeared in Northrop's published histories differ from later versions primarily in having a taller and narrower swept vertical fin.  I've never seen one with a T-tail though that doesn't mean there wasn't one.  To the best of my knowledge, the files from Northrop's design office for that period now reside across the runway at the Western Museum of Flgiht anad are, I believe, accessible when the museum is open.

I do believe that one purpose of the underslung engine configuration was to allow the usage of alternate engines without major redesign.
« Last Edit: April 29, 2006, 11:17:26 pm by elmayerle »

Offline TinWing

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Re: N-156: Evolution of the Northrop F-5
« Reply #2 on: April 30, 2006, 06:23:32 am »
The earliest versions of the N-156 that have appeared in Northrop's published histories differ from later versions primarily in having a taller and narrower swept vertical fin. 

The same sort of design evolution occurred with the Saab Gripen.  Saab suposedly claimed that the swept vertical tail was replaced by the broader, wider chord tail to accomodate more electronics - hardly the same reason could have applied to the N-156.

I wonder if there is a fundimental aerodynamic for the shift away from a swept vertical tail?

Offline elmayerle

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Re: N-156: Evolution of the Northrop F-5
« Reply #3 on: April 30, 2006, 11:52:35 pm »
I wonder if there is a fundimental aerodynamic for the shift away from a swept vertical tail?

Well, I can't say for certain, but I find it interesting that on rather slower aircraft, your single engine Cessna's, the "square tails" on the early models appear to offer better controlability than the swept tails of later models (things learned while working on the small Cessnas).  I suspect the tails that the N-156 and Gripen ended up with are aerodynamically stiffer with their greater mean chord than swept tails and that the quarter-chord line still has adequate sweep for the necessary drag reduction.  Mind you, this is only informed speculation, but it would make sense to my mind.
« Last Edit: June 12, 2006, 10:23:24 pm by elmayerle »

Offline TinWing

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Re: N-156: Evolution of the Northrop F-5
« Reply #4 on: May 10, 2006, 03:56:56 pm »

All the patents they mention I have.

Would you happen to have found the patent for the original N156?

It is easy to find the N156F and N156T patents. :)

Offline Orionblamblam

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Re: N-156: Evolution of the Northrop F-5
« Reply #5 on: May 10, 2006, 07:09:16 pm »
Would you happen to have found the patent for the original N156?

Nope. However, I do have something of potential interest: a decent scan of a very bad photocopy of some extremely small drawings, from an old issue of Air International, Feb. 1977. It shows the evolution of the N-156, including one design (the PD-2706) which may be the T-tail I've seen people wonder about. The quality sucks, but this copy was made back when I was in high school, broke, and the library photocopier was an antique. If someone can get a better version of this *I'd* like to see it as well, including the other pages of the article.


[removed attachment - better scans later in topic - Admin]
« Last Edit: July 11, 2012, 02:21:01 am by PaulMM »
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Offline lark

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Re: N-156: Evolution of the Northrop F-5
« Reply #6 on: May 11, 2006, 09:12:14 am »
Orionblam...

"A Classic comes of age" page 67-70 /A.Int-2/1977

If APR- Utah is still your address , the article will be
on your desk in bout ten days if you like...

Offline Orionblamblam

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Re: N-156: Evolution of the Northrop F-5
« Reply #7 on: May 11, 2006, 10:29:38 am »
The address is still accurate. However, if you have an original of the magazine, scans of the pages would do me just fine. The only bits I'd be interested in high-rez, as opposed to just readible, are the bits I posted above... the drawings.
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Offline PaulMM (Overscan)

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Re: N-156: Evolution of the Northrop F-5
« Reply #8 on: May 11, 2006, 10:48:02 am »
I seem to recall lark doesn't have a scanner?

BTW lark I've got a spare one, if you live anywhere near London, UK you can have it for free.
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Offline lark

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Re: N-156: Evolution of the Northrop F-5
« Reply #9 on: May 11, 2006, 11:08:48 am »
Thanks for the very kind offer Overscan
but I'm somewhere on the Continent...

"Device" is planned for this Summer,so when the
days are about to shorten, the files will lengthen... :)

Offline elmayerle

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Re: N-156: Evolution of the Northrop F-5
« Reply #10 on: May 11, 2006, 08:43:20 pm »
If/when those drawing get scanned, I'd like a set too.  What would be nice is if drawings turned up, too, on the N-285B derivative for a USN supersonic trainer/light strike aircraft.   The original N-156 design couldn't maintain slow enough approach speeds for carrier landings, so they developed a new wing and a revised forward fuselage for better back seat visibility.  I wish I'd been able to copy the one brochure of that one that I've seen.

Offline Orionblamblam

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Re: N-156: Evolution of the Northrop F-5
« Reply #11 on: May 11, 2006, 09:54:30 pm »
  What would be nice is if drawings turned up, too, on the N-285B derivative for a USN supersonic trainer/light strike aircraft. 

Bah. Boooooring. The N-156 derivative I want to see is the aerospace trainer. Rocket powered, meant to fly out of the sensible atmosphere for astronaut training. Somewhat like the NF-104, but apparently more integrated.
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Offline PaulMM (Overscan)

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Re: N-156: Evolution of the Northrop F-5
« Reply #12 on: May 12, 2006, 03:24:28 pm »
Fang to Freedom Fighter

March 1955: "Tally-ho" project, N-156TX . 2 x turbojets in underwing pods, mid-fuselage unswept wing, long one piece canopy over tandem seats, low set tailplane.

N-156NN Naval fighter. Not unlike Grumman Panther in configuration, engines brought into the fuselage with separate intakes on the sides of the fuselage. T-tail, full span flaps and provision for tractor type landing gear. November 1955, PD-2706.

1956: 7 configurations, 6 with designations. Known: PD-2821 (Jan), PD-2832 (March), PD-2879A (May), PD-2879B (October) PD-2879D (Dec).

PD-2789D became N-156T. New single seat design, designated N-156F, is the 7th configuration mentioned above without a PD- designation.

Source:

  • Jerry Scutts, Northrop F-5/F-20, Ian Allan Modern Combat Aircraft 25
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Offline Orionblamblam

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Re: N-156: Evolution of the Northrop F-5
« Reply #13 on: May 13, 2006, 05:50:05 pm »
The ultimate N-156 development: the N-205B space trainer... Mach 3, 250,000+ feet. Sadly, no illustrations as yet.
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Offline PaulMM (Overscan)

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Re: N-156: Evolution of the Northrop F-5
« Reply #14 on: May 27, 2006, 06:32:43 pm »
Bigger versions of the N-156 studies. Best I could do from a photocopy- they are tiny, white on blue.



[removed attachment - better scans later in topic - Admin]
« Last Edit: July 11, 2012, 02:21:32 am by PaulMM »
"They can't see our arses for dust."
 
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