Republic F-105 Design evolution

[Antonio]

From a very beatiful book: The Republic F-105 Thunderchief by Robert D Archer. American Aircraft Series 1. Aeropublishers. This monographic starts in the way I love to read the story: from the drawing board not from the first flight of the aircraft described! (This is my message for all aerospace writers)

Enjoy evolution!. The AP-63 (I also love to know the manufacturer designations) was developed from the RF-84 Thunderflash

 

[elmayerle]

Re: Republic AP-63

The evolution seemed obvious after seeing the YF-105A. It started as a fighter derivative of the RF-84F. I imagine there are some other interesting variations along the design history.

 

[Antonio]

Re: Republic AP-63

Your comment is very interesting, Evan. I'm fascinated with Republic fighters because I see an evolution line, step by step, that starts with the Seversky fighters in the 30's and ends with the F-105. Every design has something in common with the precedent one.

P-43 to P-44, P-43 and P-44 to P-47, P-47 to Jet Thunderbolt, Jet Thunderbolt and P-69 to P-84, P-84 to AP-63, AP-63 to F-105.

By the way, in my research on US Types I have found to versions about the P-84 development story. Anybody can tell me where is the truth.

1. X-Fighters. USAF experimental and prototype fighters, XP-59 to YF-23. Steve Pace. Motorbooks. ISBN 0-87938-540-5.

"In May 1944, the new GE TG-180 turbojet (later J35) performance was so exciting that US Air Materiel Command released a General Operational Requirement for a 600 mph pursuit interceptor airplane that could double as a fighter-bomber.Republic came up with a TG-180 powered P-47 but the concept was quickly selved in favour of an all-new design"

2. The P-84 was a private iniciative from Republic to replace the P-47 which interested the Air Force enough to place an order.
Please, follow this link
http://home.att.net/~jbaugher1/p84_1.html


Private iniciative or design competition?. Please help me.

PD: I have more support from other books to believe in the design competition story. There was almost one more submission, from North American. North American studied P-51 piston-jet powered P-51 derivatives that were the bassis for its TG-180 powered RD1265 study.
This study was later converted to naval fighter and submitted to the US Navy jet fighter requirement in December 1944 as Model NA-134. This aircraft became the XFJ-1 Fury.

 

[overscan (PaulMM)]

Re: Republic AP-63

According to the Squadron-Signal F-84 book, the first is the correct version.

 

[Antonio]

Re: Republic AP-63

Thanks a lot for the info Overscan

I'm writing a little amateur article about US Fighter evolution in collaboration with Lark and we have found more contradictions from different sources. Most authors seem to ignore that the real aircraft competed with other designs before leaving the drawing board. Others ignore that there is a maturation process before a design is frozen....no comments


To illustrate this maturation process lets see another step before AP-63 became the Thud. Again from Robert Archer's beatiful book

 

[elmayerle]

Re: Republic AP-63

You left out the initial step, P-35 to XP-41 to P-43. There also were some interesting steps between the straight-wing and swept-wing F-84F/RF-84F (I know I've seen pictures of the first prototypes of both with a F-84E style bubble canopy). Issue 3 of Justo Miranda's "Unknown" series looked at the "jet P-47" concept in greater depth. So, really, there is a steady continuum of development from the P-35 to the F-105.

*wry laugh* It does make one wonder what might have happened with the P-35's "twin in appearance", the Re2000, if it had continued it's evolution.

 

[Antonio]

Re: Republic AP-63

You're right about the P-35

http://home.att.net/~jbaugher1/p35_1.html
(A comprehensive history can be found here)

One of the P-35 trends in its evolutive path to P-47 was size increase, this was not the case for its "Italian twin". The Re 2000 evolved to be a more refinated air superiority fighter through Re 2001, 2002, 2005 to 2006.
Re 2007 was a jet fighter with nothing in common with the Re 2000 family.
I think if they ever thought to follow Kartveli's steps they found impossible because there were any radial engine comparable to that produced in the USA...what do you think about?

Last year I tried to buy Miranda's books but it was impossible to contact him via email. Tophe told me he is ill. My only picture about the Jet Thunderbolt (courtesy of Lark) can be found attached here.

I also have this drawing from Le Fana de L'Aviation: hors série Nº16. L'USAAF, 1944-1947. La première Génération Jet. A very interesting work on US Aviation. Highly recommended!
The drawing shows an early design from Republic AP-23 (later designated XP-84). The tail section is similar from that of the Republic XP-69. Which I can understand is where is the jet exhaust?. It is supposed that AP-23 had a tail exhaust from its conception.

 

[Antonio]

Re: Republic AP-63

Aerofax Minigraph 15. Republic F-84 (Swept Wing Variants) Story
Kevin Keaveney

Summer 1944: USAAC propsed to convert the P-47 to jet power by installing a TG-180 (later J35) turbojet in its aft fuselage.
November 1944: the jet P-47 was impractical due to the turbojet duct requirements. A new optimized design (AP-23; P-84) came on the Republic drawing boards
February 1946: XP-84 maiden flight
March 1947: swept wing P-84 studies AP234 and AP23X (afterburner variant) but Air Materiel Command was not interested
Early 1949: swept wing F-84 studies submitted again
AP23 SLAR (swept wing, light weight: 14,000 lb, afterburner, radar)
AP23 SA
AP23 SL
AP23 SR
AMC refused to authorize program funding

November 1949: AP-23-M Swept wing F-84 submitted. The Air Force ordered it under designation YF-96A.

 

[overscan (PaulMM)]

Re: Republic AP-63

Republic AP-63, from Aviation Week 5th December 1958, via Tony Buttler.

 

[elmayerle]

If you look at the initial prototype of the RF-84F, it's got the bubble canopy of the straight-winged F-84 and a solid nose that looks rather fighter like rather than having the flat panels for the camera windows.

 

[thewanderingmind]

8) Looking at the article above on the F-108 competitors, http://www.secretprojects.co.uk/forum/index.php?topic=647.msg4878#msg4878[/color]]http://www.secretprojects.co.uk/forum/index.php?topic=647.msg4878#msg4878, finding the Republic AP-75 was a real blast for an F-105 lover. This is so obviously just another step along in the process... One can almost picture it blazing along at 1500 kts and 500 feet on its way into the Hanoi area...

 

[thewanderingmind]

Well, shucks! :-[ I guess I need to learn how to preview before I post...

 

[nugo]

Hi pometablava!

Aerofax Minigraph 15. Republic F-84 (Swept Wing Variants).

Whether there are there figures or drawings of folowing planes:

AP-23 SLAR
AP-23 SA
AP-23 SL
AP-23 SR

 

[hesham]

From a very beatiful book: The Republic F-105 Thunderchief by Robert D Archer. American Aircraft Series 1. Aeropublishers. This monographic starts in the way I love to read the story: from the drawing board not from the first flight of the aircraft described! (This is my message for all aerospace writers)

Enjoy evolution!. The AP-63 (I also love to know the manufacturer designations) was developed from the RF-84 Thunderflash

My dear Pometablava,


From the book; Republic F-105 Thunderchief,by Larry Davis and David Menard;

 

[fightingirish]

RARE FACTORY MODEL AIRCRAFT: From Republic F-84 to F-105 in Miniature
Four pristine original 1950s factory models showing the F-84 Thunderjet, F-84F Thunderstreak, F-105 Thunderchief, and a unique surprise concept, all in 1/32-scale. [...]

Video:

View: https://youtu.be/c-suMJqGllk

https://youtu.be/c-suMJqGllk

 

[overscan (PaulMM)]

Here's something I did years ago from the SACs

 

[Kiltonge]

A montage about F-105D Thunderstick 2 , AvWeek 20 Jan 1969.

The new spine was 12 to 13 inches high and Republic stated that it had much more volume than was needed for Tstick-2. It didn't appreciably increase drag but did improve directional stability.

Modfications:

• Modified APN-131 doppler, by Laboratory for Electronics, to improve ground speed accuracy from 13ft/sec to 4ft/sec and vertical resolution from 1 degree to 4 arc-minutes.
• Added new Singer-General Precision inertial platform with an MTBF of 1,800hrs compared to 128 for its predecessor. Indicated as GAVRS on the block diagrams.
• Added ITT ARN-92 LORAN digital receiver.
• Upgraded NASRR radar to mod R14K, with improved graze angles down to 4 degrees. This mod was in preference to addition of a laser rangefinder. It also added terrain-clearance prompts as used in the F-104G.
• Added QRC-380 ECM.

CEP intended to be 50ft when released from distance of 15,000ft.

Unfortunately the LORAN receiver required a straight and level approach run of about 25 miles. However once the LORAN distance-to-go matched the radar slant range to target, the nav system could be put into 'freeze' mode and the GE analogue toss-bombing computer was engaged, allowing the pilot to manoeuvre.

Also, the digtal LORAN could not talk to the analogue inertial, so to update the latter the pilot had to key-in the readings from the LORAN display.

 

[Scott Kenny]

• Upgraded NASRR radar to mod R14K, with improved graze angles down to 4 degrees. This mod was in preference to addition of a laser rangefinder. It also added terrain-clearance prompts as used in the F-104G.

1960s/70s laser rangefinders were pretty bad (bulky and fragile), so this makes sense.