SaparotRob
Unter Gemeine Geschwader Murmeltier XIII
"Ask the man who owns one."
could the Allison engine have done what the Rolls Royce Merlin did?
- Thread starter CobberKane
- Start date
Shortround6
Lieutenant General
The is just a lot of confusion about the Merlin "tolerance" saga. In part because nobody now knows (unless they have access to the written records) what tolerances anybody is talking about.
I have have an old book with some tolerances for a Merlin II with as built tolerances and allowable wear before rebuild.
What is not given was the allowable production tolerances.
For instance the permissible weight difference for for the pistons fitted/selected to one engine was 1/2 oz.
The Permissible variation in weight between any two pairs of rods, pistons, pins fitted to one engine was 1 oz.
Maybe you could fit a heavy piston on a light rod?
In any case this seems like a pretty tight specification. but it does not tell us at what point a piston was too light or too heavy to be sent from the inspection area to the assembly area (and they sure did NOT go from a the machinery area to assembly without stopping at inspection).
There seems to have been a degree of selection on pistons and rods as far as weight went.
Some of the tolerances are very tight on this Merlin II engine. I doubt that Ford was making any money building car engines to these tolerances.
But RR was NOT trying to make parts that would interchange between every engine. Ford could do that in part because a Ford car engine was operating at much less pressure in the cylinders and much lower stresses in the parts and block.
I don't have the tolerances of the cylinder bore but the Pistons were supposed to be oval?
Diameter of piston at top measured in the axis of the gudgeon pin.............................................5.36650 max/5.34450min
Diameter of piston at top measured at right angels to the axis of the gudgeon pin..............5.370 max/ 5.368 min
Diameter of piston at bottom measured in the axis of the gudgeon pin.....................................5.372 max/5.370 min.......................................max permissible wear 5.560
Diameter of piston at bottom measured at right angels to the axis of the gudgeon pin......5.380 max/5.378 min........................................max permissible wear 5.570
This does not sound like sloppy tolerances as fitted to me?
Crankshafts were allowed two regrinds in service.
The journals were supposed to be.................. 3.349/3.34850.........................................permissible worn.................................3.347
1st regrind.................................................................3.344/3.34350
2nd regrind...............................................................3.339/3.33850
Perhaps there were other parts that had greater tolerance.
But again, this was as fitted, Not as "manufactured."
I am not seeing a room for sloppiness but we are not looking at final assembly procedures.
Was some of this stuff built oversized and "polished" to fit ? (forget the file nonsense)
This may have been a long standing practice and in small scale production it might have reduced scrape.
It is hard to salvage a too small part.
But in large scale production the time needed to correct too many large parts outweighs the benefits of not tossing out the bottom of the tolerance range.
I have have an old book with some tolerances for a Merlin II with as built tolerances and allowable wear before rebuild.
What is not given was the allowable production tolerances.
For instance the permissible weight difference for for the pistons fitted/selected to one engine was 1/2 oz.
The Permissible variation in weight between any two pairs of rods, pistons, pins fitted to one engine was 1 oz.
Maybe you could fit a heavy piston on a light rod?
In any case this seems like a pretty tight specification. but it does not tell us at what point a piston was too light or too heavy to be sent from the inspection area to the assembly area (and they sure did NOT go from a the machinery area to assembly without stopping at inspection).
There seems to have been a degree of selection on pistons and rods as far as weight went.
Some of the tolerances are very tight on this Merlin II engine. I doubt that Ford was making any money building car engines to these tolerances.
But RR was NOT trying to make parts that would interchange between every engine. Ford could do that in part because a Ford car engine was operating at much less pressure in the cylinders and much lower stresses in the parts and block.
I don't have the tolerances of the cylinder bore but the Pistons were supposed to be oval?
Diameter of piston at top measured in the axis of the gudgeon pin.............................................5.36650 max/5.34450min
Diameter of piston at top measured at right angels to the axis of the gudgeon pin..............5.370 max/ 5.368 min
Diameter of piston at bottom measured in the axis of the gudgeon pin.....................................5.372 max/5.370 min.......................................max permissible wear 5.560
Diameter of piston at bottom measured at right angels to the axis of the gudgeon pin......5.380 max/5.378 min........................................max permissible wear 5.570
This does not sound like sloppy tolerances as fitted to me?
Crankshafts were allowed two regrinds in service.
The journals were supposed to be.................. 3.349/3.34850.........................................permissible worn.................................3.347
1st regrind.................................................................3.344/3.34350
2nd regrind...............................................................3.339/3.33850
Perhaps there were other parts that had greater tolerance.
But again, this was as fitted, Not as "manufactured."
I am not seeing a room for sloppiness but we are not looking at final assembly procedures.
Was some of this stuff built oversized and "polished" to fit ? (forget the file nonsense)
This may have been a long standing practice and in small scale production it might have reduced scrape.
It is hard to salvage a too small part.
But in large scale production the time needed to correct too many large parts outweighs the benefits of not tossing out the bottom of the tolerance range.
GregP
Major
As far as the Allison goes, there were only three acceptable sets of pistons: nominal, .010 over, and .020 over. The pistons could be a bit on the sloppy side, but the rings could not. Rings were specified at an end gap.
The shape of the pistons is almost irrelevant. They are what they are so the metal expansion at operating temperature makes the pistons about round. The accuracy of fit is almost entirely dependent on the piston rings, 5 sets of rings for each piston on an Allison V-1710. If you check the Table of Fits on an Allison V-1710, there are 5 piston rings.
- The top ring in groove has an end gap of .0025" -.0040." That's a total tolerance of .0015".
- The second ring in the groove has the same tolerance.
- The third and fourth rings in groove has a tolerance of .002" - .0035". Again, a total tolerance of .0015."
- The 5th ring in groove has a tolerance of .001" - .0025".Again, a total tolerance of .0015".
In a Merlin II, the ring end gap tolerances are .025 - .030" with permissible gap after wear at 0.085", per piston and connecting rods fits and clearances, (Figure 64), Merlin Manual dated late 1938. So, the Allison E-series engine actually had a tighter end gap clearance than a Merlin II, but the Allison E-series was a later engine than a 1938 Merlin II. A comparable Merlin may have had clearances similar to the Allison, and very likely did.
Packard auto engine V-12 crankshaft clearances were .005" - .0025", so you're looking at a total tolerance of .0025", or about 0.00635 mm. I don't have the piston ring gap clearances for a Packard V-12 AUTO engine, but they are pretty decent.
The entire tolerance issue for Merlins revolves around Packard wanting to engineer the Merlin for replacement parts being interchangeable and not for fitting a part to an engine. When a Packard Merlin is running right, it makes almost exactly the same power as a Rolls-Royce Merlin running right, within acceptable tolerances between "identical" engines. But the Packard Merlin is a bit easier to overhaul because it requires less "fitting." Later RR Merlins had more interchangeable parts anyway, and less "fitting."
That comes for current warbird owners running Merlins. Most people in the U.S.A. are running Packard Merlins because we can find parts for them easier. I'd bet most European owners run Rolls Royce Merlins for the same reason, but you can find both types in both places, with happy owners. I don't know of ANY owners who claim their Merlin brand runs better than the other one. Both seem to run just fine when things are operating correctly.
I HAVE seen two P-51s that, when flying side by side, one requires 2" more MAP to fly formation. But that isn't an engine thing, it's a airframe fit issue. If you swap the two Merlins the draggier airframe STILL requires 2" more MAP than the other airframe. Both are P-51Ds! Individual airframe DID have tolerances for speed and engine power.Some were FAST and some were just a bit slower. But, they all could cruise within a small gap of fuel consumption.
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ThomasP
Chief Master Sergeant
!. I do not think that anyone has said that a RR Merlin is better than a Packard Merlin?
2. The tolerances for the Merlin crankshaft, pistons, etc, would have been figured out and specified prior to the prints being handed over to Ford or Packard, with said tolerances allowing ~100% interchangeability of parts. To have any other method would have required all of the people in charge of RR engineering and manufacturing to be buffoons.
3. The only reason there would have been any 'fitting' or selection of particular parts would have been if the parts were not made to the specification. The effects of any specific failure to meet specification would have applied to Ford and Packard as much as for RR.
4. Did Ford and Packard have a lower percentage of out of specification parts coming off the production line than RR? is not a question I can answer. However, the only quality difference there would have been, whether for universal interchangeability or in terms of sets, would have been due to the quality of workmanship based on the machinery used, the skill of the workers, and the time allowed to manufacture the parts - none of the difference would have been due to the RR blueprint specs. Some out of spec parts would have been used anyway - with the awareness and acceptance of potential problems among the responsible agencies. In this case there would sometimes have been a requirement for 'fitting' and/or rework in one form or another. RR, Ford, and Packard, would all have had significant numbers of parts that fell into this category. Unless Ford and Packard discarded all of the parts that did not meet initial spec, there would have been 'fitting' and/or rework going on at the Ford and Packard factories also.
5. Depending on what type of system (ie room air conditioner or space shuttle environmental control module) and the quality control requirements for the parts (ie 90% of the room air conditioners have to achieve a 5 year life vs the space shuttle environmental control module requiring a 0% failure rate for 1 mission) the same factors may come into play today as in WWII.
In todays machine shops, small numbers of parts that are initially out of spec are usually sent to a tool room for rework (if possible) to allow the parts to meet spec. If the numbers are large there may be special manufacturing lines set up. Sometimes the parts can not be made to meet spec, in which case a request for variance may be sent to the responsible agency. Sometimes the request comes back with an OK to ship as is. Sometimes it will be OK to ship as long as the parts are labeled/tracked correctly. Sometimes the parts are given a different category, such as to be issued in emergencies only.
2. The tolerances for the Merlin crankshaft, pistons, etc, would have been figured out and specified prior to the prints being handed over to Ford or Packard, with said tolerances allowing ~100% interchangeability of parts. To have any other method would have required all of the people in charge of RR engineering and manufacturing to be buffoons.
3. The only reason there would have been any 'fitting' or selection of particular parts would have been if the parts were not made to the specification. The effects of any specific failure to meet specification would have applied to Ford and Packard as much as for RR.
4. Did Ford and Packard have a lower percentage of out of specification parts coming off the production line than RR? is not a question I can answer. However, the only quality difference there would have been, whether for universal interchangeability or in terms of sets, would have been due to the quality of workmanship based on the machinery used, the skill of the workers, and the time allowed to manufacture the parts - none of the difference would have been due to the RR blueprint specs. Some out of spec parts would have been used anyway - with the awareness and acceptance of potential problems among the responsible agencies. In this case there would sometimes have been a requirement for 'fitting' and/or rework in one form or another. RR, Ford, and Packard, would all have had significant numbers of parts that fell into this category. Unless Ford and Packard discarded all of the parts that did not meet initial spec, there would have been 'fitting' and/or rework going on at the Ford and Packard factories also.
5. Depending on what type of system (ie room air conditioner or space shuttle environmental control module) and the quality control requirements for the parts (ie 90% of the room air conditioners have to achieve a 5 year life vs the space shuttle environmental control module requiring a 0% failure rate for 1 mission) the same factors may come into play today as in WWII.
In todays machine shops, small numbers of parts that are initially out of spec are usually sent to a tool room for rework (if possible) to allow the parts to meet spec. If the numbers are large there may be special manufacturing lines set up. Sometimes the parts can not be made to meet spec, in which case a request for variance may be sent to the responsible agency. Sometimes the request comes back with an OK to ship as is. Sometimes it will be OK to ship as long as the parts are labeled/tracked correctly. Sometimes the parts are given a different category, such as to be issued in emergencies only.
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wuzak
Captain
Isn't that just another variation of the myth?
Before the 60 series RR was developing the Merlin at an alarming rate so mass production was not an option, I have no doubt the earliest Merlin III-XII and XX needed extra work fitting parts from various contractors but once the 60 series became the engine of choice standardisation could commence.
GregP
Major
Apparently, you've never rebuilt a Merlin. There are several things that require "fitting" on ANY Merlin.
One such item is the valve seats. On a Merlin, you have to unscrew the old valve seats and torque in the new ones and, once at the proper torque, the seat snaps off. It's supposed to be at the right height, but is often off by a bit.
Merlin head bolts must be torqued every 25 hours!
On an Allison, you torque the heads during assembly and never have to touch them again. A Merlin has about 11,500 parts. An Allison has about 7,000 parts. Why use 8 screws when 25 will work just as well?
There is a nice long list of ways the Merlin could have been improved upon as far as servicing and assembly goes, but the engine serves VERY well as-is. Still, there is no reason why some things had to be done the way they were done, and the Allison COULD have been a great performer had there been a concentrated effort to make that happen. Alas, in the real world, the integral 2-stage unit was never developed.
The title of this thread can be answered with a simple "Yes." It would have required development of an integral 2-stage supercharger, but that was never approved nor funded by the U.S. government. So, reality being what it is, that unit was never developed. The fact that it COULD HAVE BEEN developed is a "what if," but the integral 2-stage unit was developed for the Merlin, and there is no technical reason why it could NOT have been so developed for the Allison.
The Allison had many things to recommend it. It was much easier to assemble, held a tune longer, and was more rugged than a Merlin.
That being said, the Merlin was and is a superb engine with performance to wish for and a few characteristics you had to live with if you wanted that performance. History tells us the Merlin was EXCELLENT, and I have no intention of saying otherwise. If I had a warbird, I'd be very pleased to fly either engine. If I had a choice, I'd opt for a Merlin-powered bird simply because I love some of the birds powered by the Merlin.
My first choice would be a Spitfire Mk IX but a P-51D/K would serve quite nicely.
Edit: I'd avoid a radial-powered bird simply because I don't have a 25-year old curvy girlfriend to help wipe off all the oil.
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GregP
Major
No, according to owners.
I believe the owners. I am acquainted with several, me not being one, unfortunately.
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Shortround6
Lieutenant General
The Merlin, as already mentioned, was evolving considerably.
And the British had ideas to improve it which they couldn't always incorporate due to the need to produce what they were already making rather the introduce the "improvements".
The Packard V-1650-1 is part of this. What Packard initially got were the drawings and sample engine/s for the Merlin XX engine. However RR had already designed a the two piece block while Packard was tooling up and it was decided that Packard would got into production first with the two piece block as it wasn't going to delay Packard production to change the block design. Why tool up for the old design? The British factories did change over later.
Packard used the Bendix carburetor mainly because that was standard US practice. NO American engine maker used their own carburetor. From Wright and P & W down to Continental and Lycoming, American engine makers pretty much bought the carbs for specialty carb makers. Packard found a Carb from Bendix that would work and if it needed different mounting holes or something else they modified the engine to suit rather than build their own carburetor shop to copy the British carbs or Bendix supplied the carb with flanges and bolt holes to suit the locations to the Merlin engine.
A later Allison was rather different than an early (1940) Allison and late Merlin's were different than early Merlins.
Both got longer lasting while making more power.
Packard built 13 marks of Merlins for the British and V-1650s run from the -1 through the -25 (all odd numbers but not all built) by the time the P-82 saga ends.
There was room for a fair degree of overlap.
And the British had ideas to improve it which they couldn't always incorporate due to the need to produce what they were already making rather the introduce the "improvements".
The Packard V-1650-1 is part of this. What Packard initially got were the drawings and sample engine/s for the Merlin XX engine. However RR had already designed a the two piece block while Packard was tooling up and it was decided that Packard would got into production first with the two piece block as it wasn't going to delay Packard production to change the block design. Why tool up for the old design? The British factories did change over later.
Packard used the Bendix carburetor mainly because that was standard US practice. NO American engine maker used their own carburetor. From Wright and P & W down to Continental and Lycoming, American engine makers pretty much bought the carbs for specialty carb makers. Packard found a Carb from Bendix that would work and if it needed different mounting holes or something else they modified the engine to suit rather than build their own carburetor shop to copy the British carbs or Bendix supplied the carb with flanges and bolt holes to suit the locations to the Merlin engine.
A later Allison was rather different than an early (1940) Allison and late Merlin's were different than early Merlins.
Both got longer lasting while making more power.
Packard built 13 marks of Merlins for the British and V-1650s run from the -1 through the -25 (all odd numbers but not all built) by the time the P-82 saga ends.
There was room for a fair degree of overlap.
GregP
Major
I'd like to know the reason for that, very early engines with copper style HG needed the bolts torqued down then have the engine run up to temp and torqued a second time once cooled, I don't know why torqued bolts needed to be re-torqued over and over.
ThomasP
Chief Master Sergeant
Hey GregP,
re "One such item is the valve seats. On a Merlin, you have to unscrew the old valve seats and torque in the new ones and, once at the proper torque, the seat snaps off. It's supposed to be at the right height, but is often off by a bit." and "Merlin head bolts must be torqued every 25 hours!"
I have primarily been addressing the idea that the tolerances had to be tightened by Ford or Packard to aid in production. Your examples are a matter of design/assembly/maintenance procedures, and do not address the myth involving the tolerances.
Were the valve seats not torqued down and then 'fitted' in the same manner on the Ford or Packard built Merlins?
re "One such item is the valve seats. On a Merlin, you have to unscrew the old valve seats and torque in the new ones and, once at the proper torque, the seat snaps off. It's supposed to be at the right height, but is often off by a bit." and "Merlin head bolts must be torqued every 25 hours!"
I have primarily been addressing the idea that the tolerances had to be tightened by Ford or Packard to aid in production. Your examples are a matter of design/assembly/maintenance procedures, and do not address the myth involving the tolerances.
Were the valve seats not torqued down and then 'fitted' in the same manner on the Ford or Packard built Merlins?
FLYBOYJ
"THE GREAT GAZOO"
There are many aircraft (especially helicopters) that have continual torque requirements that are set by the manufacturer, engine and airframe
Thumpalumpacus
Colonel
Everything loosens under vibration, doesn't it?
wuzak
Captain
Given that in this day and age the owners are using old parts, reconditioned parts, or re-manufactured parts and are essentially hand building the engine, I would think that more "fitting" is involved now than in the factory in period.
Reluctant Poster
Tech Sergeant
- 1,776
- Dec 6, 2006
As I stated previously, I did not intend to start the RR vs Packard debate again. I was drawing (I thought) attention to Maurice Olley's recollection of events regarding Merlin and Ford.
A few facts.
Rolls Royce produced more Merlins than Ford and Packard COMBINED.
Rolls Royce produced 1411 Kestrels in 1936. 1937 saw a changeover from Kestrels to Merlins. I have compiled the following Merlin production table from various sources. Rolls Royce had produced ~24,000 Merlins by the end of 1941 while Ford and Packard had barely got started. As I have posted previously, the Merlin was the second most produced aircraft engine at that time, more than the much vaunted Liberty which was produced by 5 manufacturers and only exceeded by the Hispano V8s.
As can be clearly seen Rolls Royce was in full mass production well before Ford and Packard.
Rolls Royce increased their production by a factor of 10 in an incredibly short time. A magnificent achievement. It should be obvious that they did so by mass production methods.
The myth that Packard (or Ford) made a silk purse out of a sow's ear dos not withstand scrutiny and should be consigned with all the other fairy tales.
A few facts.
Rolls Royce produced more Merlins than Ford and Packard COMBINED.
Rolls Royce produced 1411 Kestrels in 1936. 1937 saw a changeover from Kestrels to Merlins. I have compiled the following Merlin production table from various sources. Rolls Royce had produced ~24,000 Merlins by the end of 1941 while Ford and Packard had barely got started. As I have posted previously, the Merlin was the second most produced aircraft engine at that time, more than the much vaunted Liberty which was produced by 5 manufacturers and only exceeded by the Hispano V8s.
As can be clearly seen Rolls Royce was in full mass production well before Ford and Packard.
Rolls Royce increased their production by a factor of 10 in an incredibly short time. A magnificent achievement. It should be obvious that they did so by mass production methods.
The myth that Packard (or Ford) made a silk purse out of a sow's ear dos not withstand scrutiny and should be consigned with all the other fairy tales.
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Geoffrey Sinclair
Staff Sergeant
- 1,278
- Sep 30, 2021
I can see GM allocating $500,000 to Allison in the second half of the 1930's given what it was going in Australia, putting in about half that amount to start Australian aircraft manufacture from basically scratch in October 1936 on the promise of an order, which took until April 1938 to be signed and then was for a whole 40 trainers.
In 1934, after a DC-2 came second (but first on handicap) in the Britain Australia Air Race, the RAAF Chief of Staff and the Minister of Defence separately asked General Motors in Australia (GMH or General Motors-Holden) whether there was any interest in building the DC-2 in Australia, but GM had sold out of Douglas.
In early 1935 a proposal was put to build aircraft and their engines in Australia, the Commonwealth Government convened conferences as well as industry undertaking discussions including using a Government appeal for such a company to convince shareholders to put together a local manufacturing syndicate with the funds and expertise. GM was one of 3 companies that in 1935 contributed 12,000 pounds each, about 48,000 dollars to start things, like sending a mission around the world to see what designs were available. Assurances were needed about tariffs and access to facilities, and recording the government promises. Military and civilian aircraft were to be made in that order and exports were also mentioned both airframes and engines to be locally made, plus a factory complex needed to be built.
As Australia was assembling motor vehicles, not making them, this was a major step up in manufacturing capacity, given at the end of 1930's when the ex WWI imperial gift aircraft required overhauls (many had been stored in tents with dirt floors) Australian industry lacked the capacity nor had the interest in acquiring the capacity to do the work. Not without lots more aircraft to work on. As of 1 January 1935 the RAAF had 69 aircraft, plus 28 on order or in storage. A mid 1930's contract for overhaul of Moth and Wapiti wings received 1 high price reply, admittedly the wings had to be repaired in Victoria, not shipped interstate, which cut the possible numbers of replies.
The long term aim was complete manufacture of aircraft by Australia using mostly Australian raw materials. In February 1936 Wing Commander L.J. Wackett, Squadron Leader H.C. Harrison (technical man) and Squadron Leader Murphy, RAAF Chief Workshop Operator were sent on a 5 month tour to visit overseas aircraft industries to determine what design to manufacture. Italy, France, Germany, Czechoslovakia, Holland, Britain and the United States were visited.
The framework being it was expected it would take 5 years from industry initiation before manufacture of a first line defence aircraft could be made (under peacetime conditions), so it was best to start with a simpler design that would a) use Australian raw materials, b) establish manufacture that would be applicable to other aircraft types, c) achieve being able to manufacture a range of aircraft types as quickly as possible, d) introducing designs that would lend themselves to good jigging and tooling so in an emergency production of larger quantities could be carried out by semi skilled labour. A radial engine was preferred as easier to build.
The first design should use as much steel as possible given 1936 Australia had plenty of steel but lacked reliable supply of non ferrous alloys, aluminium and magnesium. The design should be made by regular workshop personnel given the wartime need to significantly increase output. The design should incorporate features likely to be standard practice for some time, a) stressed skin wing and construction, b) all metal construction, c) low wing monoplane type, d) retractable undercarriage, e) variable pitch propeller.
The result was the choice of the North American design, British types of better performance in terms of defence capabilities had not been successfully and easily produced in quantities. The British offered the Fairey Battle light bomber (production started in May 1937) and the Westland Lysander Army Co-operation aircraft (production began in May 1938). The North American design first production, as the BT-9, was in July 1936. The single row Wasp engine it used of around 500 HP could be turned into a 1,000 HP twin Wasp with some redesign but built using the same machine tools and fixtures.
In September 1936 the Australian government told the British what was going to be built. The Commonwealth Aircraft Corporation formed on 17 October 1936, taking over the Tugan company along with its personnel and building a new factory in Melbourne on Victorian Government land. Essington Lewis was Chairman of the company and Lawrence Wackett was appointed Manager. The authorised capital was £1,000,000 paid up to £600,000. The shareholders were
Broken Hill Proprietary Company Ltd £200,000
Broken Hill Associated Smelters Pty Ltd £150,000
Imperial Chemical Industries of Australia and New Zealand £90,000
General Motors-Holden's Ltd £60,000 (Around US $240,000)
The Electrolytic Zinc Company of Australasia Pty Ltd £50,000
Orient Steam Navigation Company Ltd £50,000.
GM was originally going to have 25% of the company, that was wound back to 16 then 10%, given the politics of British is Best, with ideas like GM was really there to acquire knowledge of the inevitably superior British designs and engineering or it was there to force the purchase of the North American design. Offers to British firms to replace GM were made, they were ignored or replies were along the lines of "only if you build our designs".
In January 1937 the government indicated it would order the North American design as the Wirraway, subject to the usual contract negotiations being successful. Construction of the Melbourne factory began in April 1937 and the initial buildings were ready for occupation in September, further expansions occurred pre war, a near doubling of the floor space. An example of the fixed undercarriage version of the design arrived in Australia in August 1937, one with retractable undercarriage in September. An order for 40 Wirraway including engines was approved in January 1938 and the contract signed in April 1938, the Wirraway name made public on 6 April 1938, the first engine was built in January 1939, the first Wirraway flight on 27 March 1939, official delivery in July, by end July 8 engines had been officially produced, by the end of 1939, 33 Wirraway and 36 engines.
A lot of money spent before any order and the size of the order was too small to recoup the investment, though an order for an extra 60 Wirraway was approved in September 1938, plus an order for 2 prototypes for a CAC designed trainer in October. The original GM shareholding was controversial and the outcry increased when the Wirraway was chosen, plenty of chances for and pressure on GM to sell their holding. And while the RAAF was becoming increasingly concerned about deliveries of aircraft ordered from Britain as the 1930's went on it was mainly confined to combat types, not trainers. Then in mid 1939 a new wholly public owned operation, the Government Aircraft Factory, was set up to manufacture the first combat type, the Beaufort rather than contract CAC to build it, with part of the reasons for doing so the GM holding in CAC.
Also lapped?
Reluctant Poster
Tech Sergeant
- 1,776
- Dec 6, 2006
Not quite Packard was moving into Buick territory in the late 30s. See my previous post.
Post in thread 'An interesting read about the Packard built Merlin engine.' An interesting read about the Packard built Merlin engine.
FLYBOYJ
"THE GREAT GAZOO"
But did they?
Good information but I don't see how this is relevant to the original comment
