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Gee and Loran


Ratch

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To the best of my knowledge everything was 'internal' for both and none of my scale plans hint at any external differences when used.

 

HTH.

 

Pat.

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16 hours ago, Ratch said:

Is there any external equipment fitted on aircraft with these navigational systems?

Gee had a large whip aerial, the only aircraft I know of where this could be internal was the Mosquito where it's wooden structure wouldn't interfere with signal reception.

Loran was a similar system operating on lower frequencies and would require an external aerial on all metal aircraft. A quick google of loran aerial will show up several images ofdifferent designs of loran aerial

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1 hour ago, Ratch said:

Funny, all I had come up was internal equipment and ground based masts.

If there isn't an aerial on the aircraft, it's not going to pick up the signals for the internal equipment to interpret, and an aerial has to be outside on a metal aircraft to work, ergo there will be an external aerial of some sort on most Gee or Loran equipped aircraft Heres some:-

 

JASDF_C-1FTB(28-1001)_HF_LORAN_antenna_r

N36900-221__42411.1709752342.jpg?c=1

359DE033-DEAA-411B-8B0B-40728A4274DD.jpeAircraft_Loran_Antenna_21368-900x600.jpg

 

RId36kCvenlHesDoSPEBTNP2E1P3etuNBEVALoI6

 

And here's a shot of a Gee equipped Lancaster, the large whip aerial can just be seen on top of the canopy just ahead of the astrodome

screenshot-2020-04-20-at-11.29.02.png

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The previous posts show the whip and trailing antenna used with LORAN.  The MIT 1948 tome on Long Range Navigation states, "All airborne Loran equipment now in service has been designed with expectation that it is to be used with a trailing antenna."   The length of 120 feet or about one quarter wavelength is suggested.  Although satisfactory results could be obtained with considerably shorter lengths.  Many downsides for the use of a trailing antenna, imagine the hazards of formation flying or evasive action while trailing a long weighted wire.  With a suitable tuneable coupling unit, a fixed antenna was found to be satisfactactory.  Later in the war, whip antenna for LORAN appeared on Allied bomber aircraft and some smaller aircraft such as the Mosquito.

 

The US AN/APN-4 was designed such that this equipment was completely interchangeable with Gee.  Reportedly, the Gee units could be exchanged for the APN-4 with a few minutes of work.

 

Don

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Huh! I did not know that LORAN dated to WW2.

 

I used it on ships in the mid '70s; ISTR I was decent with it...would get pretty small triangles. 

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3 hours ago, Ratch said:

I'm looking at WW2 Liberators, originally fitted with Gee, later changed to Loran.

I would look for a whip antenna somewhere close to where the LORAN receiver would have been installed, either on the upper mid-fuselage above the command deck or on the nose above the navigator's compartment in the nose.  Or, perhaps the aircraft's mission allowed for the use of a trailing antenna, if so there would be no external difference between the Gee or APN-4 installation.

 

Here's an image of a B-24H that has an antenna above the navigator's compartment that looks suspiciously like a LORAN antenna.

 

doubletrouble.jpg

 

Don

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Because of the nature of Carpetbagger missions, there aren't many pictures of those aircraft, hence my question.

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@Dave Swindell is absolutely right - LORAN fitted to B-24s required an external aerial. It's not always easy to see in photos, but once you've spotted it, then it becomes easier to make out in other pics. Martin Streetly describes it below:

 

IMG_3673(1)

 

and it looked like this, running parallel to the fuselage from a support just aft of the nose turret, to another support behind the cockpit windows on the port side. See the scrap views of B-24s C and J below.

 

IMG_3675

 

and in real life you can just make it out

 

IMG_3671(1)

 

 

All photos from here, and posted solely for the purpose of research/discussion in accordance with UK Copyright Law

 

IMG_3674(1)

 

 

SD

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1 hour ago, SafetyDad said:

LORAN fitted to B-24s required an external aerial. It's not always easy to see in photos, but once you've spotted it, then it becomes easier to make out in other pics. Martin Streetly describes it below:

Thanks for that @SafetyDad, I was trying to remember where I'd seen that recently. This installation was for 223 Sqn special ops Liberators, installed by the RAF shortly after they had received their Liberators from the USAAF, I don't know if the USAAF used a similar installation for their carpetbagger missions.

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51 minutes ago, Dave Swindell said:

Thanks for that @SafetyDad, I was trying to remember where I'd seen that recently. This installation was for 223 Sqn special ops Liberators, installed by the RAF shortly after they had received their Liberators from the USAAF, I don't know if the USAAF used a similar installation for their carpetbagger missions.

 

I've checked in Pat Carty's Secret Squadrons of the 8th AF, and I can't see any pictures where a similar Loran aerial fit is visible on the B-24s illustrated. The photos in the book aren't exactly numerous, so it could be there and just not easy to see. On the other hand, the Carpetbagger illustrated in Streetly's book ('Bama Bound, Lovely Libba I think), doesn't have this aerial.

 

SD

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@SafetyDad  That's a good find in Streetly's book.  For me, finding a clear picture of a Gee or LORAN  fixed antenna is very rare.  I hope that someone can find an image of the external fixed LORAN antenna used on Carpetbagger aircraft.

 

Don

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