Hey, what's the Mk.X, chopped liver?
The "best fighter engine in the world"
- Thread starter wuzak
- Start date
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Hey, what's the Mk.X, chopped liver?
Canadian version of the Mk III.
MACHIA
Airman
The ALLISON V1710 ( if ) it had a turbosupercharger during the war , like the E27 variant , would have been the best inline reciprocating engine in that time period . The technology of the E27 was ahead of its time , but it came too late in the war . But even then , thermal stress on existing metals was problematic .
It was an engine too late for WW2 , and when perfected , not considered an important milestone due to the interest in turbines .
Still , the ALLISON V1710 got her pilots home when damaged to a point that no Merlin could likely survive .
It was an engine too late for WW2 , and when perfected , not considered an important milestone due to the interest in turbines .
Still , the ALLISON V1710 got her pilots home when damaged to a point that no Merlin could likely survive .
- Thread starter
- #44
wuzak
Captain
Thousands of P-38s were built with a V-1710 and a turbocharger.
The E27 was not turbocharged. It was a 2 stage engine with a power recovery turbine.
Installation of the E27 would have been problematic for conventional single engine aircraft, as it was looong, and the exhaust was in the middle at the back. The turbine could not be remotely mounted like a turbocharger as it had to connect to the back of the engine.
It was considered for installation into the P-63. It would have been good for a medium sized bomber or twin engine fighter.
The problem with the E27 was, as you say, the ability of the turbine to cope with the exhaust temperatures. The turbine itself was based on the unit from the GE C-series turbocharger, as used in the P-47. Improvements allowed increased temperature resistance, but still not enough.
Further development would have seen an air cooled turbine developed. But Allison weren't interested in developing a product for which they had no current market, so didn't pursue it too far.
The E27 was not turbocharged. It was a 2 stage engine with a power recovery turbine.
Installation of the E27 would have been problematic for conventional single engine aircraft, as it was looong, and the exhaust was in the middle at the back. The turbine could not be remotely mounted like a turbocharger as it had to connect to the back of the engine.
It was considered for installation into the P-63. It would have been good for a medium sized bomber or twin engine fighter.
The problem with the E27 was, as you say, the ability of the turbine to cope with the exhaust temperatures. The turbine itself was based on the unit from the GE C-series turbocharger, as used in the P-47. Improvements allowed increased temperature resistance, but still not enough.
Further development would have seen an air cooled turbine developed. But Allison weren't interested in developing a product for which they had no current market, so didn't pursue it too far.
fastmongrel
1st Sergeant
Both engines are virtually identical in construction it would take an expert to tell them apart if the name plates were removed why would one be more resistant to damage than the other. Both engines if they took a hit in the oil or water cooling systems had literally minutes or even seconds before they seized.
Even an air cooled radial engine was a gonner if it took a hit in the oil cooling system. A WWII engine in combat always ran on the edge between running and blowing up it didn't take much to stop it.
- Thread starter
- #46
wuzak
Captain
I think the V-1710 may have a small advantage in how they dealt with steam in the cooling system.
fastmongrel
1st Sergeant
I am no expert but there shouldn't be any steam in a cooling system. If you have steam you have a leak, the cooling system is pressurised and has Glycol in the coolant both of which raise the boiling point.
yulzari
Staff Sergeant
Hmm. What effect did the end of licencing for Merlins at the end of the war have when NA could no longer put new Packard Merlins in the P82? Surely the performance improved with these wonder Allisons?
swampyankee
Chief Master Sergeant
- 4,020
- Jun 25, 2013
At first blush, the P-82E was about 17 mph slower than the Merlin-powered P-82B. On the other hand, there were probably enough other changes between the P-82B and P-82E for that difference to be illusory, as the aircraft had different equipment -- the EEW of the E model was over 10% greater than that of the B.
North American P-82E Twin Mustang (P-82E)
North American P-82B Twin Mustang (P-82B)
My vote for best fighter engine goes to the R-2800: it was reliable, efficient, and reasonably tolerant of minor combat damage or mishandling.
PWR4360-59B
Senior Airman
- 379
- May 27, 2008
My vote R-2800, no liquid cooling is a good thing, you just don't need all the extra piping and systems, it gives another vulnerability. There are many stories of radials flying back to base with cylinders missing. And for an inline vote that would be Allison, simple fact all high performance race Merlins use Allison con rods, that alone has to say something. The Brit engines just overly complicated with a bunch of goofy fasteners etc. I thought I read that the Packard units where a huge improvement over the Brit stuff.
fastmongrel
1st Sergeant
Why don't racers use Allison engines if they are so superior.
Packard built Merlin's and V1650s are identical apart from some ancillaries like carbs and Magneto's to the Rolls Royce built engines. Have a guess which goofy fasteners the Packard built engines used.
Shortround6
Major General
You can read all sorts of stuff about how bad RR Merlin Engines were compared to Packards.
Doesn't mean any of it is true.
There has probably been more utter crap written about RR Merlins than any other 3 engines in history.
Doesn't mean any of it is true.
There has probably been more utter crap written about RR Merlins than any other 3 engines in history.
fastmongrel
1st Sergeant
I am not denigrating the V1710 in anyway it was a great engine and the RAF Army cooperation squadrons kept their Mustang Mk Is going till they ran out of spare parts.
- Thread starter
- #54
wuzak
Captain
Merlin rods were designed for 2,000hp and worked well. Race Merlins are pushing past 3,500hp, so it isn't a great surprise that the original rods don't survive at higher levels. That the V-1710 rods do survive may be a sign that they are over-designed and heavier than what they needed to be.
But it also may be that there aren't too many spare Merlin rods around. Whereas there may be quite a few V-1710 rods available, as they aren't being used in racing V-1710s....
Regarding "I read that the Packard units where a huge improvement over the Brit stuff" you need to find better reading material.
Of all the aero engines used in WW2, the Merlin did more to win the war than any other.
fastmongrel
1st Sergeant
My take on the Merlin has always been it was a good engine that was in the right place at the time. If the RAF had had to wait for the supposedly superior engines to arrive then it would have fought with Gloster Gladiators till 1943.
swampyankee
Chief Master Sergeant
- 4,020
- Jun 25, 2013
Goofy fasteners? If you mean Whitworth fasteners, arguably they had a better thread form than contemporary US thread forms or the succeeding unified system.
I do remember reading that Rolls-Royce tended to use a lot of small screws where other engine makers would use a few larger ones.
Shortround6
Major General
Closer spacing of fasteners on covers/access plates might be the way to go if your gasket material is, shall we say, suspect?
There are a lot of things than many of these engine makers bought from outside vendors. Gasket material being one of them.
Other countries/makers may have different suppliers.
There are a lot of things than many of these engine makers bought from outside vendors. Gasket material being one of them.
Other countries/makers may have different suppliers.
- Thread starter
- #58
wuzak
Captain
He may have meant the BA screws hat were used all over the place.
PWR4360-59B
Senior Airman
- 379
- May 27, 2008
Small and fine threads are not a good thing in cast aluminum, they are easily stripped, especially if it is a fastener that is in constant use, meaning removed and reinstalled many times. I doubt the threaded holes where inserted in any form in the day, as that would have really slowed up production.
There are Allisons in racing and the ones built properly do very well. I don't feel any of the inline engines are very good for racing applications they are not constructed strong enough.
There are Allisons in racing and the ones built properly do very well. I don't feel any of the inline engines are very good for racing applications they are not constructed strong enough.
- Thread starter
- #60
wuzak
Captain
"I don't feel any of the inline engines are very good for racing applications they are not constructed strong enough."
And, yet, they keep winning races!
Being built "strong enough" is an interesting question.
The Merlin is less than half the capacity of the R-3350 (which is used by a few air racers) but makes much more than half the power.
The Merlins may be running as much as 160inHg MAP* - which is a massive amount of pressure for a WW2 engine. And running several hundred rpm higher than the normal maximum speed.
I should think they need to be plenty strong.
*This MAP may be beyond what actually increases shaft power, but may improve speed using exhaust thrust.
And, yet, they keep winning races!
Being built "strong enough" is an interesting question.
The Merlin is less than half the capacity of the R-3350 (which is used by a few air racers) but makes much more than half the power.
The Merlins may be running as much as 160inHg MAP* - which is a massive amount of pressure for a WW2 engine. And running several hundred rpm higher than the normal maximum speed.
I should think they need to be plenty strong.
*This MAP may be beyond what actually increases shaft power, but may improve speed using exhaust thrust.
