Other Packard Merlin powered aircraft?

Unless somebody actually assembled engines for Packard and RR Factory in England OR was involved in overhauling them then the reported differences are often hearsay.

For the pistons and connecting rods it didn't really matter how they were made. When they went to put them in the engine they had the same standards. Same fit to the bore, same fit of the piston rings and the same allowable variation from lightest to heaviest pistons/piston-rod assembly in a particular engine. You could assemble one engine with all light pistons and the next engine with all heavy pistons but the allowable variation in the same engine was the same.
We can argue about more or less time assemble dozens of engines per day or trying to sort parts in an overhaul facility but that is different.
Unless somebody can come up with the allowable limits as manufactured/assembled then most of the stories are hearsay.
I have an old mechanic text book on engine overhaul so it may be 2nd source?
It gives the allowable difference in weight for set of pistons and also the max difference in weight for set/pair of pistons and rods
The Chapter on the Merlin engine is from Page 77 to page 113. It is for a Merlin II engine, later engines may differ.

Permissible variation in weight of pistons selected for one engine = 1/2 oz.
Permissible variation in weight between any two pairs of connecting rods, pistons, and pins fitted to one engine + 1 oz.
A bunch of information on boring and lapping cylinders.
This is for overhaul, not initial assembly.

Price on the this book is all over the place. Some are priced like a old used text book and some are priced like they are printing on gold leaf with gem stone inlays.
The author wrote a number of books on being a machinist, machine practices and mechanics.

GrauGeist said:

Off the top of my head, there was one (of three) XP-63 that was being tested with a V-1650 at one point.

Click to expand...

I believe I saw a sketch of what it might have looked like in the P-63 thread.

rochie said:

Spitfire XVI's had packard merlins.

they were often faster, tougher and longer ranged than plain old RR merlin variants

Click to expand...

I just read the other day that the Mk XVI had engine problems (not joking).

wuzak said:

Lancaster IIIs also had Packard Merlins.

On occasion Lancasters would end up with a mix of RR and Packard Merlins. They had to be careful where they put the Packard Merlins, because if there were Packards on one side and RR Merlins on the other, the Lanc would fly in circles.

Click to expand...

Just fly inverted for 30 minutes per hour!

pbehn said:

I just read the other day that the Mk XVI had engine problems (not joking).

Click to expand...

I wonder about that, since if they were using the same engines from the same source as those for the P-51, WTF? Did the RCAF crews modify them for higher speed at lower altitudes, like some RAF crews did with the Typhoon's Sabre, with disastrous results?

I also read that when the P-51B first started flying in the ETO the USAAF found out the hard way that the stock spark plugs they had on hand did not work well in the V-1650 engine, as in Very Much Not Very Well. Engine failure would occur NLT maybe 20 hours. I read of one guy who even had to splash down in a French river on one of his first flights, with only a few hours on the airplane. Now that would be a pisser! Did the V-1650-3 need spark plugs the RAF had but the USAAF did not? Were they using plugs that had been meant for the P-47 or P-38? Or was it that the Spit XVI was fitted with V-1650 when built and no one thought to swap out the installed plugs at Castle Bromwich with the good ones?

Shortround6 said:

Unless somebody actually assembled engines for Packard and RR Factory in England OR was involved in overhauling them then the reported differences are often hearsay.

Click to expand...

When the British agreed to give the Chinese 100 Hawk 81A in return for a later delivery of Kittyhawks, there was a big problem. As is done today, the engines and the airframes were bought separately by the government contracting agencies. The Brits refused to give up 100 V-1710 C series engines to go with the Hawk 81A'sand there was no room on the production lines to get them. So much for the Flying Tigers! But Allison pointed out they had a large quantity of V-1710 parts that had been rejected as non-compliant. So a team of techs and engineers started building engines using those rejected parts, hand selecting them, doing additional machining as required, and adding custom made shims and bushings and so forth to enable them to be used. The resut was that the AVG ended up with the best V-1710-C engines every built, able to put out more power and with less fuel consumption. The AVG pilots reported that compared to the stock P-40B and C's some had flown before the ones in China were noticeably faster. "Blueprinting" engines works.

Shortround6 said:

Unless somebody actually assembled engines for Packard and RR Factory in England OR was involved in overhauling them then the reported differences are often hearsay.

For the pistons and connecting rods it didn't really matter how they were made. When they went to put them in the engine they had the same standards. Same fit to the bore, same fit of the piston rings and the same allowable variation from lightest to heaviest pistons/piston-rod assembly in a particular engine. You could assemble one engine with all light pistons and the next engine with all heavy pistons but the allowable variation in the same engine was the same.
We can argue about more or less time assemble dozens of engines per day or trying to sort parts in an overhaul facility but that is different.
Unless somebody can come up with the allowable limits as manufactured/assembled then most of the stories are hearsay.
I have an old mechanic text book on engine overhaul so it may be 2nd source?
It gives the allowable difference in weight for set of pistons and also the max difference in weight for set/pair of pistons and rods
The Chapter on the Merlin engine is from Page 77 to page 113. It is for a Merlin II engine, later engines may differ.
View attachment 717089
Permissible variation in weight of pistons selected for one engine = 1/2 oz.
Permissible variation in weight between any two pairs of connecting rods, pistons, and pins fitted to one engine + 1 oz.
A bunch of information on boring and lapping cylinders.
This is for overhaul, not initial assembly.

Price on the this book is all over the place. Some are priced like a old used text book and some are priced like they are printing on gold leaf with gem stone inlays.
The author wrote a number of books on being a machinist, machine practices and mechanics.

Click to expand...

Having done automotive engine balancing for 20 years, I cringe at the tolerance variations I see there. Of course, the aircraft engines didn't see the RPMs that the V-8s I worked on (7,000 rpm not being unusual).

MIflyer said:

I wonder about that, since if they were using the same engines from the same source as those for the P-51, WTF? Did the RCAF crews modify them for higher speed at lower altitudes, like some RAF crews did with the Typhoon's Sabre, with disastrous results?

I also read that when the P-51B first started flying in the ETO the USAAF found out the hard way that the stock spark plugs they had on hand did not work well in the V-1650 engine, as in Very Much Not Very Well. Engine failure would occur NLT maybe 20 hours. I read of one guy who even had to splash down in a French river on one of his first flights, with only a few hours on the airplane. Now that would be a pisser! Did the V-1650-3 need spark plugs the RAF had but the USAAF did not? Were they using plugs that had been meant for the P-47 or P-38? Or was it that the Spit XVI was fitted with V-1650 when built and no one thought to swap out the installed plugs at Castle Bromwich with the good ones?

Click to expand...

It didnt elaborate. The Spit XVI had a Packard 266 engine which was a version of the V-1650-7 which was which was the Packard Version of the RR 66. Ive no idea what the detail differences were, if any, the problem may have been some screw up with carbs or instruments.

MIflyer said:

When the British agreed to give the Chinese 100 Hawk 81A in return for a later delivery of Kittyhawks, there was a big problem. As is done today, the engines and the airframes were bought separately by the government contracting agencies. The Brits refused to give up 100 V-1710 C series engines to go with the Hawk 81A'sand there was no room on the production lines to get them. So much for the Flying Tigers! But Allison pointed out they had a large quantity of V-1710 parts that had been rejected as non-compliant. So a team of techs and engineers started building engines using those rejected parts, hand selecting them, doing additional machining as required, and adding custom made shims and bushings and so forth to enable them to be used. The resut was that the AVG ended up with the best V-1710-C engines every built, able to put out more power and with less fuel consumption. The AVG pilots reported that compared to the stock P-40B and C's some had flown before the ones in China were noticeably faster. "Blueprinting" engines works.

Click to expand...

One book about the flying tigers says the custom assembled engines put out about 50 additional horsepower. This led to gear box fails on occasion in combat as the long nose engine was near it's limit at 1150-1200 HP. The Tiger's 81A's performance in combat with 1250 HP engines aided successful engagements

special ed said:

One book about the flying tigers says the custom assembled engines put out about 50 additional horsepower.

Click to expand...

Yes, I think I read a comment by a former AVG pilot saying their 81A's could hit 370 mph.

machine shop tom said:

Having done automotive engine balancing for 20 years, I cringe at the tolerance variations I see there. Of course, the aircraft engines didn't see the RPMs that the V-8s I worked on (7,000 rpm not being unusual).

Click to expand...

You also weren't working on 5.380 in diameter pistons were you ?
One recovered piston is marked 3 lbs 0 oz and 1 dram (got to keep the elves in line) so a 1/2 oz extreme variation is just over 1%.
About 1360 grams.
No idea what the rods weighed.

machine shop tom said:

Having done automotive engine balancing for 20 years, I cringe at the tolerance variations I see there. Of course, the aircraft engines didn't see the RPMs that the V-8s I worked on (7,000 rpm not being unusual).

Click to expand...

I think the mean and max piston speed would be around he same.

MIflyer said:

I wonder about that, since if they were using the same engines from the same source as those for the P-51, WTF? Did the RCAF crews modify them for higher speed at lower altitudes, like some RAF crews did with the Typhoon's Sabre, with disastrous results?

I also read that when the P-51B first started flying in the ETO the USAAF found out the hard way that the stock spark plugs they had on hand did not work well in the V-1650 engine, as in Very Much Not Very Well. Engine failure would occur NLT maybe 20 hours. I read of one guy who even had to splash down in a French river on one of his first flights, with only a few hours on the airplane. Now that would be a pisser! Did the V-1650-3 need spark plugs the RAF had but the USAAF did not? Were they using plugs that had been meant for the P-47 or P-38? Or was it that the Spit XVI was fitted with V-1650 when built and no one thought to swap out the installed plugs at Castle Bromwich with the good ones?

Click to expand...

Found it, on a modelling site but modellers delve into all sorts "Problems with the licence-built engines limited introduction to front-line squadrons for several months."

Shortround6 said:

so weren't working on 5.380 in diameter pistons were you ?
One recovered piston is marked 3 lbs 0 oz and 1 dram (got to keep the elves in line) so a 1/2 oz extreme variation is just over 1%.
About 1360 grams.
No idea what the rods weighed.

Click to expand...

Biggest I worked on was 4.655". Tolerances were .5 grams on parts, .5 grams per inch of radius of crankshaft counterweight. High-performance diesel would be similar to aircraft components in size, they are generally balanced to same specs as automotive.

Shortround6 said:

You also weren't working on 5.380 in diameter pistons were you ?
One recovered piston is marked 3 lbs 0 oz and 1 dram (got to keep the elves in line) so a 1/2 oz extreme variation is just over 1%.
About 1360 grams.
No idea what the rods weigh.

Click to expand...

MIflyer said:

When the British agreed to give the Chinese 100 Hawk 81A in return for a later delivery of Kittyhawks, there was a big problem. As is done today, the engines and the airframes were bought separately by the government contracting agencies. The Brits refused to give up 100 V-1710 C series engines to go with the Hawk 81A'sand there was no room on the production lines to get them. So much for the Flying Tigers! But Allison pointed out they had a large quantity of V-1710 parts that had been rejected as non-compliant. So a team of techs and engineers started building engines using those rejected parts, hand selecting them, doing additional machining as required, and adding custom made shims and bushings and so forth to enable them to be used. The resut was that the AVG ended up with the best V-1710-C engines every built, able to put out more power and with less fuel consumption. The AVG pilots reported that compared to the stock P-40B and C's some had flown before the ones in China were noticeably faster. "Blueprinting" engines works.

Click to expand...

Having balanced and blueprinted many engines, I can attest to the fact it does work. Not only do these operations increase output, they also increase reliability and longevity.

pbehn said:

I think the mean and max piston speed would be around he same.

Click to expand...

With automotive engine parts becoming much lighter in the last 20 years or so, piston speed is not the issue it used to be prior to that.

There is little doubt that the the ability to build precision high performance engines as improved tremendously over the years. This is due to many reasons.

The Aircraft engines of WW II were very carefully built as they were. This is comparing them to standards of their day. Packard was building 800 engines a month in later part of 1942, for example.
That is 26.66 engines a day or 320 pistons a day (not including spares) every day for months on end. Aircraft engines were making more power per pound of engine weight than racing car engines (granted they had the advantage of scale). and the racing car engines only had to last a few hours. A lot of the race car engines were running on special fuels. or at least alcohol.
There was always a fight between producibility and precision.

This may be incorrect as it did not come from an original source document, but I once read that the appearance of unusual problems usually associated with the Merlin 266 in the Spitfire Mk XVI were due to the use of 150 grade almost from the time of its first missions. IIRC it took a bit of time to shake out the details such as different spark plugs and timing adjustments among other things. Maybe?

MIflyer said:

Did the RCAF crews modify them for higher speed at lower altitudes, like some RAF crews did with the Typhoon's Sabre, with disastrous results?

Click to expand...

Do you have a source for the RAF crews modifying the Typhoon's Sabre for higher speed at lower altitudes? Thanks.

From Allied Aircraft Piston Engines of World War II, by Graham White (SAE Press):
V-1650-1 used in P-40F, Kittyhawk II, Lancaster III (as Merlin 28); Canadian Hurricane, Kittyhawk II, P-40F (as Merlin 29); Canadian Mosquito XX, Australian Mosquito 40, P-40F/L (as Merlin 31, 33 [same as Merlin 23]); Lancaster III (as Merlin 38 [same as Merlin 22])
V-1650-3 used in Mustang III, P-51B/C, XP-60D (as Merlin 68)
V-1650-5 used in feasibility study for P-39 (or P-63)
V-1650-7 used in Mustang III/IV, P-51C/D/F/K (as Merlin 69)
V-1650-9 used in P-51C/D/H/K (also built by Continental)
V-1650-11 used in P-51L, P-82B
V-1650-21 used in P(F)-82B
V-1650-23 used in XP-82, P-82B
V-1650-25 used in XP-82, P-82B
Merlin 224 used in Lancaster I/III [same as Merlin 24]
Merlin 225 used in Canadian Mosquito 25/26 [same as Merlin 25]
Merlin 266 used in Spitfire L.F. XVI [same as Merlin 66]
Also lists -- not assigned to particular airframe types
V-1650-13 similar to -3 except boost control
V-1650-15 similar to -5 except boost control
V-1650-17 similar to -7 except boost control
V-1650-19 similar to -11 except variable-speed blower drive

I think I found all the references in that chapter.
The Merlin In Perspective, by Alec Harvey-Bailey, (Rolls-Royce Heritage Trust) has slightly different assignments:
Merlin 28 used in British-built Lancaster III, Canadian Lancaster X
Merlin 29 used in Canadian-built Hurricane
Merlin 31 used in Canadian-built Mosquito
Merlin 33 used in Canadian- and Australian-built Mosquito
Merlin 38 used in British-built Lancaster III, Canadian-built Lancaster X
Merlin T38 used in T.A.C. Lancaster
Merlin 68 used in British- and Canadian-built Lincoln II
Merlin 69 used in Canadian- and Australian-built Mosquito
Merlin 224 used in British Lancaster III, Canadian Lancaster X
Merlin 225 used in Canadian- and Australian-built Mosquito
Merlin 266-P used in Spitfire 16L.F.
Merlin 300 used in British- and Canadian-built Lincoln
Merlin 301 used in anadian- and Australian-built Lincoln
V-1650-1 used in Kittyhawk II
V-1650-3 used in P-51B/C
V-1650-5 used in Kingcobra (P-63)
V-1650-7 used in P-51D
V-1650-9 used in P-51H
V-1650-9A used in P-51D
V-1650-11 used in P-51H, XP-82
V-1650-13 used in Mustang (probably P-51B/C)
V-1650-15 used in Kingcobra (P-63)
V-1650-17 used in P-51D
V-1650-19 not allocated to any aircraft

Sorry for the long post, but my machine won't let me open a text file right now.