[MRCA] [MRCG] [Milsurplus] WTB - Vintage Mil Aircraft Radio Components

Mon Oct 1 20:37:50 EDT 2018

Anecodotally, I can relate some representative MTBF number for C-130A/B and KC-135E aircraft.

In the first case, the C-130 A, two 618T-1 systems were installed, using 180L-3 couplers to long wires.  The aircraft were ex- Rhode Island Air National Guard, and had been converted to a constant-flow slurry system for firefighting use.  The aircraft also served off-season as US military contract aircraft, performing myriad functions that required a nearly complete military avionics suite, including UHF and HF comms.  Typically, the 618-T R/Ts were not problematic, despite being over forty years old, and in a typical season, perhaps 1 R/T unit out of a 3 aircraft fleet would require service.  Most typically, the bench repair involved aligning the RF translator, and perhaps replacing a driver tube.  Based up this service, the R/T's were exhibiting perhaps 1 failure per 150-200 flying hours.  On the other hand, the 180L-3 couplers might have exhibited perhaps ten times that failure rate.  They were, for the most part, worn out.  I replaced silver ribbons, re-plated autotransformer windings, and replaced a lot of relays.

In the second case, I was working on Wyoming Air Guard C-130Bs, same 618T-1 installation x2, but the failure rate was much lower, as we would order 490T-9 couplers to replace the 180L-3s until our 9 aircraft all had two 490Ts.  This made the tuning cycle much shorter, much to the relief of the crew, and the radio!

In the last case, it was the ARC-190 in the KC-135E/R in Phoenix.  Basically, it never failed.  Even when it would sit on the ramp in Phoenix on a 120 degree day and bake, it didn't fail.  We would remove the radios for bench check just so the new guys would know were they were located.  Occasionally, we would get a coupler fault, which was almost always fixed with a shot of nitrogen to top off the pressurized coupler up at the top of the vertical stab. (not the most pleasant work)  I think in 20 years at the 161 ARW, I had exactly one opportunity to troubleshoot an ARC-190 on the bench, and it turned out to be a smashed pin that someone had overlooked on a connector. By the way, there was only one HF system on the KC-135, even when they had the ARC-65.  Some special mission -135s had two HFs.
My assumption is that MAC aircraft had two HF systems due to their role in carrying passengers on a regular basis.

Scott V. Johnson W7SVJ
5111 E. Sharon Dr.
Scottsdale, AZ 85254-3636
H (602) 953-5779
C (480) 550-2358
scottjohnson1 at cox.net
scott.johnson at ieee.org

-----Original Message-----
From: mrcg-bounces at mailman.qth.net <mrcg-bounces at mailman.qth.net> On Behalf Of Francesco Ledda
Sent: Monday, October 1, 2018 3:22 PM
To: 'West Coast Military Radio Collectors Group' <mrcg at mailman.qth.net>; 'mrca' <mrca at mailman.qth.net>; 'milsurplus' <milsurplus at mailman.qth.net>
Subject: Re: [MRCG] [Milsurplus] [MRCA] WTB - Vintage Mil Aircraft Radio Components

The devil is in the details. 

As Jim said before, MTBF numbers should be provided with the operational context in which were obtain.  A 618T on the back of a Jeep in South Vietnam will have different MTBF respect to a 618T in the pressurized belly of a B-747. 

The ARC-58 was tested by the Air Force and Collins in 1959. If I remember correctly, they were installed in a mix of 11 B-52s and KC-135.  The test report issued by Collins (with supervision of the Air Force) gave a ~300 hours MTBF.   This MTBF analysis is valid only for this application, and nothing else.

Few considerations:

-Helping Collins - New radios and best of the best provided by Collins

-Helping Collins – Radios maintained by very knowledgeable Collins engineers

-Against Collins – New radios with still few design and manufacturing bugs

-Against Collins – High early mortality (reliability curve -  bathtub shape)

Therefore, the 300h MTBF must be seen as a starting point that can be improved with the proper effort. This is exactly what happened to the ARC-58 in the B-52; it got better with age, like a good wine.

The same ARC-58 was used on the AN/TSC-15 Communication Central for the USAF, but it was used differently. The TSC-15 was carried to the field on a truck or air dropped.  When in full duplex mode, the ARC-58 could be ON and radiating (transmitting) 24 hours a day. I am sure that its reliability numbers were not as good.

Jim is 100% right.  The operational context is half of the story when we talk about MTBF.

Best, Frank K5URG

From: milsurplus-bounces at mailman.qth.net [mailto:milsurplus-bounces at mailman.qth.net] On Behalf Of Jim Whartenby
Sent: Monday, October 1, 2018 12:21 PM
To: 'West Coast Military Radio Collectors Group'; 'mrca'; 'milsurplus'
Subject: Re: [Milsurplus] [MRCG] [MRCA] WTB - Vintage Mil Aircraft Radio Components

Ray

Don't know about the KC-135, "Standard Aircraft Characteristics" has no information on it but some articles in the "Collins Signal" indicate that the ARC-58 was originally installed.  Seems logical to me since the KC-135 refueled the B-52 and world wide comm would be desirable.  But military logic is not the same as common sense; it is easy to loose sight of why something was done.  It is relatively easy to find B-52 avionics designations (again, Standard Aircraft Characteristics to the rescue) but little seems to be available on the KC-135, possibly since it is in the support role.

Frank Ledda is the expert, as far as I am concerned, he has access to all sorts of information on Collins radios.

I don't know where you are getting your MTBF information but your numbers seem wildly optimistic to me.  DTIC article A061734 from November, 1966 has reliability information on the ARC-58 and 618T-2 under the ARC-94 designation.  AGREE data for the ARC-94 is 154 hours; 79 hours for the ARC-58.  This is far from what you reported so I would be interested in getting a copy of your MTBF data.

Now we can quibble about AGREE test data compared to Operational Conditions data but it is difficult to factor in the aircraft and it's affect on equipment reliability.  Each aircraft is its own unique environment.  The aircraft determines where on the airframe the equipment is located and what are the environmental conditions that the particular radio is exposed too.  So some radios will have high MTBF hours while the same radio installed in another aircraft will have lower MTBF hours.  At least AGREE test data is arguably the same for all radios tested since it is done under laboratory controlled conditions of altitude, humidity, temperature and vibration.

AGREE test chambers are available on eBay so one can do their own tests! <grin>  But kidding aside, if anyone has found other reliability data on DTIC or any other reliable source, please let me know; always looking for published reliability data.  It is surprising to me how secretive reliability data is.  I see reports all the time that do not even name the manufacturer nor equipment designation, it is all so hush-hush.  

To answer the question about how common the ARC-58 mounts are, the ARC-58 was designed to fit an ARINC standard  ATR-1 mount so any ATR-1 mount will accept the ARC-58 receiver-exciter or transmitter-power supply.  They show up on eBay often enough, that is where I got the examples I have.  Some have tags on them showing what equipment it was made for, other mounts have no tags at all.

Regards,

Jim

I wonder why people argue over the 10% of their differences and ignore the 90% they agree on?

  _____  

From: Ray Fantini <RAFANTINI at salisbury.edu>
To: Scott Johnson <scottjohnson1 at cox.net>; 'West Coast Military Radio Collectors Group' <mrcg at mailman.qth.net>; 'mrca' <mrca at mailman.qth.net>; 'milsurplus' <milsurplus at mailman.qth.net> 
Sent: Monday, October 1, 2018 7:45 AM
Subject: Re: [Milsurplus] [MRCG] [MRCA] WTB - Vintage Mil Aircraft Radio Components

Still beings up the question what would you be using it for. I thought most KC-135 had been refitted with 618T transceivers as soon as they became available being the ARC-58 was hardly the most reliable radio. The MTBF of the ARC-58 was around 400 hours and the MTBF of the 618T was 4,000 hours. 

But imagine that if you had a large aircraft that came with an ARC-58 only an ARC-58 will do. 

Going to assume that this is just for static display or Ham use being that none of this stuff would meet type acceptance these days. 

Sorry for all the questions but this is a fascinating subject.

And if you decide that a 618T/ARC-94 would work may be able to help.

-----Original Message-----

From: Scott Johnson [mailto:scottjohnson1 at cox.net] 

Sent: Friday, September 28, 2018 9:45 PM

To: 'West Coast Military Radio Collectors Group' <mrcg at mailman.qth.net>; Ray Fantini <RAFANTINI at salisbury.edu>; 'mrca' <mrca at mailman.qth.net>; 'milsurplus' <milsurplus at mailman.qth.net>

Subject: RE: [MRCG] [MRCA] WTB - Vintage Mil Aircraft Radio Components

-And the civil version, the 18Z3/4 was used in the early 747

Scott V. Johnson W7SVJ

5111 E. Sharon Dr.

Scottsdale, AZ 85254-3636

H (602) 953-5779

C (480) 550-2358

scottjohnson1 at cox.net

scott.johnson at ieee.org

-----Original Message-----

From: mrcg-bounces at mailman.qth.net <mrcg-bounces at mailman.qth.net> On Behalf Of Scott Johnson

Sent: Friday, September 28, 2018 6:38 PM

To: 'Ray Fantini' <RAFANTINI at salisbury.edu>; 'MRCG' <mrcg at mailman.qth.net>; 'mrca' <mrca at mailman.qth.net>; 'milsurplus' <milsurplus at mailman.qth.net>

Subject: Re: [MRCG] [MRCA] WTB - Vintage Mil Aircraft Radio Components

They were also used on the KC-135.

Scott V. Johnson W7SVJ

5111 E. Sharon Dr.

Scottsdale, AZ 85254-3636

H (602) 953-5779

C (480) 550-2358

scottjohnson1 at cox.net

scott.johnson at ieee.org

-----Original Message-----

From: mrca-bounces at mailman.qth.net <mrca-bounces at mailman.qth.net> On Behalf Of Ray Fantini

Sent: Friday, September 28, 2018 10:07 AM

To: MRCG <mrcg at mailman.qth.net>; mrca <mrca at mailman.qth.net>; milsurplus <milsurplus at mailman.qth.net>

Subject: Re: [MRCA] WTB - Vintage Mil Aircraft Radio Components

Just curious, what are you restoring that's big enough to accommodate an AN/ARC-58? I thought they were only used on the B-52

Ray F/KA3EKH

-----Original Message-----

From: mrca-bounces at mailman.qth.net [mailto:mrca-bounces at mailman.qth.net] On Behalf Of boatanchor at martasystems.com

Sent: Friday, September 28, 2018 12:54 PM

To: MRCG <mrcg at mailman.qth.net>; mrca <mrca at mailman.qth.net>; milsurplus <milsurplus at mailman.qth.net>; arc5 at mailman.qth.net

Subject: [MRCA] WTB - Vintage Mil Aircraft Radio Components

All -

I'm working on the restoration of several aircraft and need the following components. If you can help, please tell me what you have and how much $$ you require for it.

Thanks !

John WB6AZP

-- Big Black Avionics Boxes --

UHF Transmitter/Receiver "RT-178 / ARC-27"

Transmitter "T-605 / ARC-58"

Receiver/Exciter "R-761 / ARC-58"

Receiver  "R-540 / ARN-14C"

Receiver "R-322 / ARN-18"

Dynamotor "DY-66 / ARN-14"

Vertical Gyro "332D-6"

Antenna Coupler "C-1940 / ARC-58"

Antenna Coupler "CU-523 / ARC-58"

HF Power Supply "416W-1"

Altimeter Indicator "I-152C"

-- Mounting Trays --

ARC-73 Tray "MT-2699"

Shockmount for HF Power Supply "350T-1"

Mount for AN/APS13 "MT-149"

Mounting Plate "MT-80 / ARC-5"

Mounting Plate "MT-78 / ARC-5"

Mounting Plate "MT-109 / APX-1"

-- Control Boxes --

UHF Control "C-1904 / ARC-27"

TACAN Control "C-1763 / ARN-21A"

Receiver Control "C-1939 / ARC-58"

ARC-5 Control "C-38 / ARC-5" - can be rough, just need the backing plate Control "C-54 / APX-1"

-- Instruments & Other --

Jack Box "J-22A / ARC-5"

Frequency Meter "AW59"

Navigator's Radar Scope Shield "801410"

Visor for Altitude Indicator "M387"

______________________________________________________________

MRCA mailing list

Home: http://mailman.qth.net/mailman/listinfo/mrca

Help: http://mailman.qth.net/mmfaq.htm

Post: mailto:MRCA at mailman.qth.net

This list hosted by: http://www.qsl.net <http://www.qsl.net/> 

Please help support this email list: http://www.qsl.net/donate.html  <http://www.qsl.net/donate.html> ______________________________________________________________

MRCA mailing list

Home: http://mailman.qth.net/mailman/listinfo/mrca

Help: http://mailman.qth.net/mmfaq.htm

Post: mailto:MRCA at mailman.qth.net

This list hosted by: http://www.qsl.net <http://www.qsl.net/> 

Please help support this email list: http://www.qsl.net/donate.html

______________________________________________________________

MRCG mailing list

Home: http://mailman.qth.net/mailman/listinfo/mrcg

Help: http://mailman.qth.net/mmfaq.htm

Post: mailto:MRCG at mailman.qth.net

Website: http://www.mrcgwest.org <http://www.mrcgwest.org/> 

This list hosted by: http://www.qsl.net <http://www.qsl.net/> 

Please help support this email list: http://www.qsl.net/donate.html

______________________________________________________________

Milsurplus mailing list

Home: http://mailman.qth.net/mailman/listinfo/milsurplus

Help: http://mailman.qth.net/mmfaq.htm

Post: mailto:Milsurplus at mailman.qth.net

This list hosted by: http://www.qsl.net <http://www.qsl.net/> 

Please help support this email list: http://www.qsl.net/donate.html