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Seversky/Republic AP series - AP-1 to AP-100

lark

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To break the Ice :

Lets start with the AP series from Seversky Aircraft later Republic Aviation Corp.

First : AP - Army aviation project or advanced project ?
 

elmayerle

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I'm going to argue for Advanced Project, but I don't know for certain.
 

Sentinel Chicken

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Greg Goebel's "Air Vectors" stated that the P-35 had the company designation AP-1 standing for "Army Pursuit 1". It doesn't really sound appropriate for the post war period when the USAF became an independent branch of the military, but might have remained to maintain continuity in the company records.
 

lark

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AP : Army Pursuit : source - The Seversky Story - part one ,Paul R.Matt
pag 22 -Aero Album Vol.5

AP : Advanced Pursuit : Source - The Thunderfactory , Josh. Stoff
page 20
 

elmayerle

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The meaning might have evolved as the company did. I know Northrop has used several designation systems over the years.
 

Andreas Parsch

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elmayerle said:
I'm going to argue for Advanced Project, but I don't know for certain.
I'm 100% sure to have read "Advanced Project" inconnection with Republic projects in the 1950s, but I can't remember the exact source.
 

Antonio

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AP-1 was Army Pursuit for sure because the Navy version was NF-1 for Navy Fighter (Angeluzzi/Bowers) and civil projects were RC for Republic Commercial. Shortly after WWII, the designation system seems to be unified under AP letters for Advanced Project.
 

lark

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Maybe we can conclude...

Since in the course of time the Air Corps "P" designator give way for the the Air Force "F"
the meaning of AP could also have changed.
In january 1946 - AP - was still used for the Model AP-31 wich became
the XP/XF-91.
In June 1946 the "P" had become "F"

A Navy variant for the AP-31 was labelled NP-48 and a seccond
Navy variant NP-49 (NP meaning Navy Project)
Source : Air Force Legends No210 - Republic XF-91

Thus :

AP-1 - Modified P-35 for trials 1937
AP-2 - Lost out in 1937 pursuit competition.Featured flush
rectracting gear
AP-3 - Proposal with liquid cooled Allison V-1710 engine - abandoned
in favour of AP-4.
several sources of information-
to search : illustrations of the AP-3
 

lark

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AP-4 : adaption of P-35.Order of 13 a.c. in March 1939 (XP-43)
delivered in September 1940 as P-43 Lancer
Source : US Fighters 1925-1980s
Loyd S.Jones -Aero Publ.
and:21Profiles Vol.1No7

AP-5 : ---?

AP-6 : ---?

AP-7 : speed reccord aircraft. In 1938 Major Seversky used this a.c
to establish a new transcontinental speed reccord.
source :21Profile Vol.1No7
 

lark

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AP-8 : Never completed.Formed the basis for the AP-9

AP-9 : Entrant in the 1939 Air Corps fighter competition based on
AP-8. Used improved airfoil.Air Corps turned AP-9 down in
favour of Bell XP-39 .

AP-10 : Response to Air Corps circular proposal 39-770.
Design submitted in August 1939 for a light weight fighter to
be powered by a Allison V-1710 liquid cooled engine.
Army placed an order as XP-47.
XP-47A being a stripped version of XP-47.Contract signed
January 1940.
September 1940 all work on XP-47 and XP-47A was
terminated.Full scale wind tunnel model handed over to
Langley Field for testing.
In the same month the contract for the XP-47B - later to
become the Thunderbolt- was issued to Republic

Sources : Thunderbolt in Action:Gene B.Stattford-1975
ThunderFactory - Josh Stoff -1990
Warplanes of the Seccond WW-vol 4
William Green - 1969.
 

lark

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Addendum for AP-1 to AP-10.

-for 13 XP-43 read instead : YP-43 (39-704/716)

AP4-J :1400Hp prat&Whitney R-2180-1 powered proposal.
80 ordered in Sept 13,1939 as the P-44 Rocket.
order cancelled.
AP-4L : proposal with 2000Hp R-2800-7-also not constructed.
Some sources use the name "Warrior" instead of "Rocket"

sources : Air Enthusiast 10- article byWilliam Green
& Gordon Swanborough
 

overscan

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From Tony Buttler

Also, I am told by the archivists at the Cradle of Aviation Museum (the Republic archive) that AP is indeed 'Army Project' and NP 'Navy Project'. I guess AP eventually became 'Air Force Project' after 1948, but cannot confirm that. The thing is the two prefixes are not duplicated - e.g. NP-48, NP-49, NP-50 and NP-52 are US Navy designs, AP-54, AP-55, AP-57 (F-103) are US Air Force, etc. I understand that there is no complete listing still surviving for Republic projects, and there are plenty more without project numbers. If your readers want some tasty Republic Projects, take a look at 'Aviation Week' for 5-12-58.
 

lark

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Excellent information.Thank you Overscan.
The search for Aviation Week 5.12.1958 is on.

The continue :

AP-11 : no information found

AP-12 : Republic answer to R40C.Highly streamlined design
with engine behind the cockpit driving tractor contraprop
in the nose via long shaft.Illustrations showing the
design as the "Republic Rocket"

sources : AAHS journal /Winter 1995.
 

lark

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I'm unable to find the Aviation Week 5.12.1958 article
about Republic projects.
Is there someone who can help ?
Thanks in advance.
 

lark

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The Republic AP-16 /AP-19 and AP-31 are mentioned in
"American Combatplanes of the 20th Century- A compehensive reference" by Ray Wagner -Jack Bacon&Co- Nevada
page 342 /358 and 543 of the index pages.
(via Amazon- see inside)
Is there someone who haves this book and can set some light
on the above menioned designs ?

Thanks in advance.
 

lark

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AP-13 to AP-17 no info found/received.

AP-18:development of the AP-12"Rocket".Intended powerplant
Wright R-2160. Design ordered as the XP-69 in July 1941.
scale mock-up June 1942.Final configuration with
long bubble cockpit. Cancelled 1943.

Source:US Fighters 1925-1980s - Lloyd S.Jones.AeroPublishers.
 

devi

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Please tell about projects Republic Model NP-50 and Model AP-54.
 

lark

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I'm still searching for the Aviation Week of 5 December 1958
in which these designs are mentioned.
See the note which Overscan received from Tony Buttler.
 

devi

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Hallo lark!
Continue please about Seversky/Republic AP series-AP-1 to AP-100.
 

lark

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Here we go again.To my chagrin, no info found or received for
AP-19 to AP-22

AP-23 : Initial design for what became the XP-84.
A gracefull Karteveli design after briefly playing with the
idea for a jetpowered version of the Thunderbolt.
On 11 November 1944 , three XP-84 were ordered

AP-23 X : Preliminary design - March 1947 - for a sweptwing F-84.
Not accepted by the Airforce Materilal Command

AP-23 M : Final sweptwing proposal . On the 10November of 1949
ordered as the YF-96

Sources ; "F-84 Thunderjet" L.Davis-Squadron Signal
Republic F-84-Swept-wing Variants Kevin Keaveny
Aerofax Minigraph No15 -1993
The Thunderfactory - Josh. Stoff-Arms and Armour 1990
 

devi

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Hallo lark!
Is in book "Air Force Legends No210 - Republic XF-91" a designation of following projects on the basis of XF-91:
"XF-91B", competition of MX-1554 (F-102, XF-103)------Model AP-?
Competition of F-101 (WS-105A)-----------------------------Model AP-?
 

lark

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The Air Force Legends No.210 is solely devoted
to the Republic XP-91 / XF-91.
Initially Republics AP-31 design to Material Experimental - MX-809 later MX-909.Invitation to bid to the industry in December 1945.

The MX-809 project.."was created in hope of fielding a very
high speed,very high altitude daytime interceptor pursuit.." Steve Page on p.1"

Consolidated Vultee Aircraft ( Convair) model 7 the XP-92 ducted
ramjet powered proposal was the closest rival.

The F-101 and XF-103 are note in the scope of this book.
 

lark

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Error... read Steve Pace instead of Page...
 

devi

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Hallo lark!
In what competition participated Republic Aviation with projects NP-48 and NP-49?
 

lark

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The NP-48 was a proposal to the U.S.NavyIt was closely resembling
the XP-91.(Butterfly tail , wing wth inverse tapper but without the
wing tanks and rocket engines.It had a solid nose like these
planed for the F-91A.(AP-44 ?)

The NP-49 proposal used the same tail and wing arragement
but with two engines below the wing.The nose was partly glazed
and there is no stepped windscreen.

No ref. to a related Navy program found.Maybe,in the late 1940's the U.S. Navy had no need for a short range interceptor.
 

devi

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Hi lark.

If it is possible show us figures, 3-view drawings and specifications of projects NP-48 and NP-49.
F-91A--------Model AP-31-N1
 

lark

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I was not able yet to trace the info you asking for.
Maybe in the near future .
 

devi

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Dear, lark.

If it is possible, show us Seversky Model AP-3 and AP-8 (3-view drawings, figures and
specifications).
 

overscan

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Devi - please stop harassing people for info.

From Tony Buttler:

I can add details of two more Republic project numbers. AP-42 was a large USAF swept wing jet bomber, possibly in competition with the XB-47, and the NP-50 was a US Navy bomber very like the Skywarrior. Sadly there does not appear to be 3-views for any of these designs in the company archives. One always hopes that someone may find them in the US National Archives one day.
 

lark

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Gentlemen,
This is news! Thanks.

For the people interested: there is much new Republic info
thanks to Overscan and Tony Buttler in the Postwar Secret Projects
Chapter.
 

devi

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Hi lark.

If it is possible, please show us figures of projects Republic Model AP-42 and Model NP-50.
 

lark

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A few unknown in the AP-23 /F-84 series

F-84 : so called "War Reserve Fighter" proposal of the mid.sixties.
Variants with 2 or 4 wing mounted engines.
no further info.

F-84F/V : VTOL study with wing-mouted lift-cruise engines.
no further info.
 

lark

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typing error : wing-mounted of course...
 

devi

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Hi lark

Continue please and also was well if has shown pictures of those projects which have not been shown publicly ( For example: AP-3, AP-8 and so on )
 

lark

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Gentlemen,

I can't find information for the designs AP-24 to AP-30.
Is there someone who haves info ?
Thanks in advance.
 

overscan

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From Tony Buttler

Some time ago you had a thread looking at Republic project numbers. I put together a list using the numbers and information presented by forum members plus other projects that were known to me. I then sent it to the Cradle of Aviation Museum archive in America (where the Republic documents are stored) to see if they could add anything to it. Sadly, they could not, but they pointed out that quite a few versions of real aircraft would have received some of the missing numbers in the series. Consequently, the attached list is, as far as I know, the most complete that is currently available. Some of the text comes from American Secret Projects.

Republic Project Number Listing

The following are known project numbers.

AP-1 Modified P-35 for trials 1937

AP-2 Lost out in 1937 pursuit competition. Featured flush rectracting gear.

AP-3 Proposal with liquid cooled Allison V-1710 engine – abandoned in favour of AP-4.

AP-4 Adaption of P-35. Order of 13 aircraft in March 1939 (YP-43) delivered in September 1940 as P-43 Lancer.

AP-4J 1400hp Pratt & Whitney R-2180-1 powered proposal. 80 ordered Sept 13, 1939 as P-44 Rocket. Order cancelled.

AP-4L Proposal with 2000hp R-2800-7-also not constructed. Some sources use the name "Warrior" instead of "Rocket".

AP-7 Speed record aircraft. In 1938 Major Seversky used this a.c to establish a new transcontinental speed record.

AP-8 Never completed. Formed the basis for the AP-9

AP-9 Entrant in 1939 Air Corps fighter competition based on AP-8. Used improved airfoil. Air Corps turned AP-9 down in favour of Bell XP-39.

AP-10 Response to Air Corps circular proposal 39-770. Design submitted in August 1939 for a light weight fighter to be powered by a Allison V-1710 liquid cooled engine. Army placed an order as XP-47. XP-47A stripped version of XP-47. Contract signed January 1940. September 1940 all work on XP-47 and XP-47A was terminated. Full scale wind tunnel model handed over to Langley Field for testing. In same month contract placed for XP-47B - later to become the Thunderbolt.

AP-12 Republic answer to R40C. Highly streamlined design with engine behind the cockpit driving tractor contraprop in the nose via long shaft. Illustrations showing the design as the "Republic Rocket"

AP-18 Development of AP-12 "Rocket". Intended powerplant Wright R-2160. Design ordered as XP-69 in July 1941. Scale mock-up June 1942. Final configuration had long bubble cockpit. Cancelled 1943.

AP-23 Straight wing fighter project, 19.9.44. Became XF-84 Thunderjet fighter bomber prototype first flown 28.2.46.

AP-23X Preliminary design - March 1947 - for a sweptwing F-84. Not accepted by Airforce Material Command.

AP-23M Final sweptwing proposal . On the 10th November 1949 ordered as the YF-96.

AP-31 Proposal for high performance research aircraft and day interceptor, 1.46. Competition won by Convair XP-92 but AP-31 design ordered as prototype XF-91 Thunderceptor. XF-91 first flew 9.5.49 but no production.

AP-42 Heavy USAF bomber, c1944/45. Rival design to XB-46/B-47/XB-48??

AP-44A Mach 3 all-weather high altitude interceptor, early 1948.

AP-46 Development of F-84F fitted with turboprop engine as XF-84H and first flown 22.7.55. Apart from wing and cockpit, pretty well all new aircraft. No production.

NP-48 Proposal for US Navy interceptor based on XP/XF-91, c9.48.

NP-49 Proposals for US Navy interceptor with V-tail and underwing engine nacelles, c9.48.

NP-50 Naval bomber, late 1940s. Possible competitor in Douglas A3D competition (OS-111).

‘1954 Interceptor’ Three proposals made to this requirement, 1.51. One was development of AP-44A with turbo-ramjet powerplant, second the ‘XF-91B’ jet/rocket-powered development of XF-91, third a conventional turbojet plus afterburner design. Turbo-ramjet project one of competition winners and developed into AP-57 and XF-103.

NP-52 Twin-engine anti-submarine aircraft, early 1950s.

AP-54 Single engine swept wing all-weather interceptor fighter study with F-91-style wing and large tip fittings, late 1949/1950. May have been one of submissions to the ‘1954 Interceptor’ requirement.

AP-55 Twin-boom inverted V-tail lightweight fighter/interceptor project, early 1950. Later believed in competition with Lockheed F-104. Several versions drawn but none built.

AP-57 ‘1954 Interceptor’ proposal and full development into Mach 3 XF-103, 1951. Three prototypes ordered but project cancelled 8.57 before had flown.

All Weather Fighter-Bomber Study to MX1764, c1950/51.

AP-63 Swept wing fighter bomber, 1951 onwards. Numerous layouts covered by designation. Eventually design AP-63-31 built as F-105A Thunderchief to WS.306A. First example flew 22.10.55.

AP-75 Long range interceptor to WS.202A, c5.54.

AP-85 Two-seat swept-wing development of F-84F Thunderstreak, c1955.

AP-100 V/STOL fighter-bomber proposal with three large lift fans mounted in centre of wide fuselage, 1959/60.

TFX Believed Republic undertook Tactical Fighter studies to TFX requirement, 12.61. Competition won by General Dynamics/Grumman F-111.

FX Proposals for new fighter, 1965 onwards. One possibly designated FH-100. Studies included variable geometry wings but final fixed-wing proposal of 1968 rejected for McDonnell Douglas design that became F-15.

FR-150 V/STOL fighter design proposed for Sea Control Ship, 30.12.71. Lost competition to Rockwell XFV-12A.
 

lark

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Excellent work. Thanks.
No more sleepless nights :)
 

Antonio

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Superb ::)

AP-55 Twin-boom inverted V-tail lightweight fighter/interceptor project, early 1950. Later believed in competition with Lockheed F-104. Several versions drawn but none built.
I always thought that it was developed from the Thunderflash as it was the F-105...

Thanks, thanks, thanks :-*
 

lark

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I wonder if we should not try to make a list with the unnumbered designs
projected by Seversky and Republic.
One never knows what comes to light...
 
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