# F-105 Avionics



## Zipper730 (Mar 8, 2018)

I'm curious as to the automation features of the F-105's: I did read an article that described a surprising degree of automation in the aircraft. It seemed to be quite adequate for all weather capability, but seemed to be viewed as being incapable of this.

I'm curious why this was so...


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## Shortround6 (Mar 8, 2018)

You are talking about a program that covered almost two decades. Some early planes just faded from service and some later planes received extensive refits. 

The 105D was considerably upgraded over the early versions and the D was upgraded at least once. 

SO we have to know when and what versions you are referring to.


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## Zipper730 (Mar 8, 2018)

Shortround6 said:


> You are talking about a program that covered almost two decades.


That's a good point...


> Some early planes just faded from service and some later planes received extensive refits.
> 
> The 105D was considerably upgraded over the early versions and the D was upgraded at least one.
> 
> SO we have to know when and what versions are you referring to.


Okay, let's start with the following

F-105B: First production model
F-105D: Early production variants
F-105D: Vietnam-Era
F-105G: Vietnam Era


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## Shortround6 (Mar 8, 2018)

The early F-105s were NOT all weather attack planes. A range finding radar is not terrain mapping let alone terrain following. I believe the "D" was the first version
Fitted with a new more capable radar (with at least some terrain following) and a doppler navigation system. How well it worked in practice I don't know. 
Late 105Ds got a number of improvements but seem to have kept the same attack avionics.

The 105G was an upgraded 105F, both were Wild Weasel aircraft and were two seaters.


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## RpR (Mar 16, 2018)

This was the most advanced F-105 but R. Strange McNamara shut down the F-105 prod. line so he could force the F-111 on the Air Force.
It could fly blind.

Experience in Vietnam demonstrated the need for a better visual and blind bombing capability. In March 1968, the Air Force ordered development of an upgraded bombing/navigation system, incorporating a Singer-General Precision inertial navigation system, improvements to the AN/APN-131 navigation radar, and solid-state circuitry for the R-14A radar, which was redesignated R-14K. Furthermore, the digital AN/ARN-92 long-range navigation receiver replaced the problematic AN/ARN-85 receiver. The additional avionics were housed in a long, raised dorsal spine. The modified bombing/navigation system was known as Thunderstick II. F-105s with this system could achieve a bombing circular error of probability (CEP) of 50 feet (15 m) from an altitude of 15,000 ft (4,600 m). Although the first Thunderstick II aircraft flew in 1969, they were not used in Vietnam. A total of 30 F-105Ds received this modification.


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## Zipper730 (Mar 16, 2018)

RpR said:


> This was the most advanced F-105 but R. Strange McNamara shut down the F-105 prod. line so he could force the F-111 on the Air Force.


Wait, I thought he shut down the F-105 so he could foist the F-4 on the USAF, and then the F-111...


> In March 1968, the Air Force ordered development of an upgraded bombing/navigation system, incorporating a Singer-General Precision inertial navigation system, improvements to the AN/APN-131 navigation radar, and solid-state circuitry for the R-14A radar, which was redesignated R-14K.


And this allowed for blind flying?


> Furthermore, the digital AN/ARN-92 long-range navigation receiver replaced the problematic AN/ARN-85 receiver.


What did the AN/ARN-92 and -85 do? Is this a radio nav aid?


> The additional avionics were housed in a long, raised dorsal spine. The modified bombing/navigation system was known as Thunderstick II.


How did it differ from Thunderstick 1?


> F-105s with this system could achieve a bombing circular error of probability (CEP) of 50 feet (15 m) from an altitude of 15,000 ft (4,600 m).


Seems quite good.


> Although the first Thunderstick II aircraft flew in 1969, they were not used in Vietnam.


Why?


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## fubar57 (Mar 17, 2018)

Zipper730 said:


> What did the AN/ARN-92 and -85 do? Is this a radio nav aid?



Sigh.....ignore the F-4D part...

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