Production quality and finish

Compared to the Victors the Jaguar was a delight. Indeed, the rear was slightly off kilter on the Jag. The Victor 2? 32 a/c built 32 different ways…..

Even the Jaguars had discrepancies on it’s construction……………………..

They certainly did around the extreme back end as that area wasn’t fully jig built. The wings had a number of concessions on them as well.

However, when they changed Frame 25 on XX847, RSS used a purpose built jig based on the original build jig for the centre fuselage, IIRC only one of the nodes failed to line up out of approximately 12 or so. be interested to know where else was a problem though

J: #1: Limey Rosie: 12/43: Ministry of Labour classified as airframe manufacturing and repair productives: 162,142 persons, of whom 62,858 were female.
(source not to hand, but most of my notes on such things come from the Civil Official History Series).

The way production worked, in Aero as in all other Munitions, was that Designers’ drawings were reworked to de-skill the job, by chopping into small chunks: operatives at a machine might not know where their lump would go. Inspection was: at piece part level – by a safe pair of hands who may have no pre-War experience of the part; at sub-assembly level: by a person seconded from/trained by the higher-level Design Authority; at end-item level (airframe, engine, propellor), by a person acceptable to both the Contractor and MAP’s Quality organisation (then called AID/EID). The essence of it all was reliance on self-inspection at the lowest level – hence wall-posters reminding everyone what it was all about – even though piecework pay rates widely applied.

No historian has attempted to dis. this workforce: there were strikes, there was sabotage…but my goodness what a job was done.

I don’t think that Lanc above is zero kilometre.

Which brings me to the point, all the Avro engineering drawings and tools were imperial measure, not metric. If we are taking measurements, should these not be in imperial inches?

While some error limits in the Avro drawings for the Lanc are to decimal inches, the smallest general dimension unit was 1/64″. For instance, is 0.22 mm a significant error? Convert to imperial fractions of an inch. With 2 digit denominator, the value is 0. With 3 digit denominator, the value is 2/231″. It’s nowhere near 1/64″. So it’s not an error.

From my experience of Airspeed drawings they tend to use “thou inches” and not fractions for structures although stock wood, such as ply is always quoted in fraction size i.e. 1/16″.

The Horsa generally uses dimensions of 1″, 0.7″ or 0.3″ and metal parts have tolerances down to +/- 0.005″ in some places. Wooden parts are a whopping -0.0/+0.3″ tolerance 😀

A detailed list of internal dimensions was kept by the RAf air movements team regarding the Beverley fleet once it was realised that some were roomier than others !

Such as when it came round to fitting the new wings to the Nimrod MRA4s? :highly_amused:

Even the Jaguars had discrepancies on it’s construction……………………..

Its not just wartime aircraft. Its often to be found that parts that fit one aircraft won’t fit another due to the variations in shape and where fixings are (or rather where they should be!).

Such as when it came round to fitting the new wings to the Nimrod MRA4s? :highly_amused:

I don’t think that Lanc above is zero kilometre.

Which brings me to the point, all the Avro engineering drawings and tools were imperial measure, not metric. If we are taking measurements, should these not be in imperial inches?

While some error limits in the Avro drawings for the Lanc are to decimal inches, the smallest general dimension unit was 1/64″. For instance, is 0.22 mm a significant error? Convert to imperial fractions of an inch. With 2 digit denominator, the value is 0. With 3 digit denominator, the value is 2/231″. It’s nowhere near 1/64″. So it’s not an error.

Mind you, there were errors in riveting. Fred Jones, a very expert & distinguished Farnborough wreckage diagnostician from 1941, in his book “Air Crash”, pub UK 1986, gives a good example, pp 37-39. A number of Lancs were diving and then disintegrating on training flights. With one Lanc he showed that the disintegration occurred when the starboard tail fin collapsed & rotated 90 degrees onto the starboard tailplane. The fin was constructed with two long vertical channels (open box cross section, a base & two flanges) acting as spars (open side, front and rear respectively) on to which a number of ribs gave the airfoil shape of the fin. Rivet holes were to be drilled through the flanges of the channels for the skinning. Unfortunately, on one of the channels a rivet hole was drilled right through the base of the channel, not the flanges. The channel became fatigued at this point and broke with the stress of a steep dive etc.

Mike

Its an issue that persisted after WWII. Beverley Shenstone, when Chief Engineer of BEA, caused quite a stir and upset many in the industry when he commented on the quality of spares, a greater percentage of which than he was prepared to accept were a poor fit to the aircraft.

First of all: My deepest respect to all the men and women restoring warbirds. That be parts of, ‘statics’ or ‘airworthies’.

Regarding this . . . . oh man! Reminds me of a wooden something my son brought home from carpentry class in 3rd grade or something like that: No aesthetics, pure funtion. Maybe the same here?

Take care

J

Hi Jesper
Since I started the other thread you refer to I thought I better reply here, I have very little hands on experience with WW2 aircraft but am learning quickly. Attached is a photo of 2 small fragments of AVRO Lincoln cockpit rail that go behind the skin I was asking about, a quick going over gives the following measurements between rivets;
Top row Port 52mm, 55mm
Top row Starboard 52mm, 52mm
Middle row Port 14, 18, 22, 25, 25, 16, 20mm
Middle row Starboard 16, 23, 27, 26, 28, 30mm
Read into this what you will.
Regards Paul

Its not just wartime aircraft. Its often to be found that parts that fit one aircraft won’t fit another due to the variations in shape and where fixings are (or rather where they should be!).

Service life was quite short in the war years so quantity was more important than quality. I have seen examples on a/c and vehicles.

I should imagine that back in WWII, it was more a case of: As long as they fly, they are fit for purpose.