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DmdSeeker
08-28-2006, 03:47 PM
A Mustang question:

The Mustang was originaly a capable but ordinary American plane; made extraordinary by an engine upgrade in the form of the RR Merlin (and it's Packard copies).

That being the case; how come in the fullness of time the Mustang was never upgraded to a Griffon; as was the Spit?

Treetop64
08-28-2006, 03:51 PM
Originally posted by DmdSeeker:
A Mustang question:

The Mustang was originaly a capable but ordinary American plane; made extraordinary by an engine upgrade in the form of the RR Merlin (and it's Packard copies).

That being the case; how come in the fullness of time the Mustang was never upgraded to a Griffon; as was the Spit?

Now that is a very good question.

hotspace
08-28-2006, 03:55 PM
Well I guess a quick answer would be m8, that a 'Merlin' P-51 was as fast as a 'Griffon' Spitfire' to start off with and then the Mustang got even quicker the the Grif Spit as time went on so I guess they saw no need to upgrade. I guess adding a 'Griffon' to a P-51 would also take time/screw the balance/add weight etc... http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

p1ngu666
08-28-2006, 03:57 PM
they may not have thought it a worthwhile upgrade. dh didnt for the mossie. merlin or a napier sabre where there prefered choices.

plus ud haveto find extra griffons for the p51's.

the hornet, the spiritual succesor to the mossie had narrower merlins, btw

MEGILE
08-28-2006, 04:00 PM
Ahhh the Mustang V... she would have been insanely fast.

VW-IceFire
08-28-2006, 04:06 PM
Originally posted by DmdSeeker:
A Mustang question:

The Mustang was originaly a capable but ordinary American plane; made extraordinary by an engine upgrade in the form of the RR Merlin (and it's Packard copies).

That being the case; how come in the fullness of time the Mustang was never upgraded to a Griffon; as was the Spit?
Probably for two reasons I would guess. One is that the Griffon was a much larger engine and thus the modifications to the Mustang airframe would be substantial. I can see them running into problems with how to install the engine, how to rebalance everything, and yet still maintain the clean lines, superb laminar profile, and so forth.

The second would be the fact that the Mustang was cheap to produce, fairly easy to build, cheap to build, and was already at an acceptable performance level. Above acceptable really.

The opposite is true for the Spitfire I think. While the Mustang and Spitfire IX both use essentially the same engine, the Spitfire IX just breaks the 400mph mark while the Mustang is far above it. It speaks huge amounts about how clean the Mustangs lines are and how much it could get out of the engine. But with the Spitfire, in order to get that speed to bring it upto par with 1944/1945 designs you needed a much bigger engine. So they managed to fit the Griffon in and had to redesign the whole thing in the process. Production was slow and there were never nearly as many Griffon Spitfires during WWII as regular merlin Mustangs or Spitfires.

The RAF was always a little more about the quality over quantity while the USAAF balanced the two. The Mustang had quality...but it was ideal to be produced in quantity too so thats why its such a "war winner". Its more economics of money, materials, and build time than it is how good it was in combat (good enough).

I think anyways.

It'd be interesting to see what a Griffon Mustang would be.

Viper2005_
08-28-2006, 04:14 PM
Plans were made. But the war ended and the turbojet arrived.

Even during WWII, aircraft development took quite a long time.

Interestingly, the Griffon Mustang would most likely have been mid-engined.

berg417448
08-28-2006, 04:17 PM
The idea was considered. The Griffon engine was going to be mounted behind the pilot the way that the Allison was mounted in the P-39. It never made it past a mock-up.

hotspace
08-28-2006, 04:23 PM
Originally posted by berg417448:
The idea was considered. The Griffon engine was going to be mounted behind the pilot the way that the Allison was mounted in the P-39. It never made it past a mock-up.

Yep, you're right there m8:

Click (http://home.att.net/%7Ejbaugher1/p51_8.html)

leitmotiv
08-28-2006, 04:24 PM
The best answer to this question is to look at all the jet-powered aircraft prototypes being tested in 1945-6 in the U.S.A. The Me 262 scared the heck out of the AAF and Navy.

Sergio_101
08-28-2006, 04:31 PM
Post war racers and packard may have offered
some insight into the results of a Griffon marrige.

Packard developed the Merlin to nearly 2,400 hp.
The V-1650-9 was WEP rated at 2,200+ hp.
Those numbers delivered a very fast plane.
The P-51H was capable of 400mph+ at most
altitudes and 487mph at it's critical altitude.

Racers married the Griffon to the P-51 in at
least three cases that I am aware of.

Red Baron airlines RB-51 was the first.
it was a winner till they crashed it.
Much modified it was capable of over 500mph at sea level.

"Miss Ashley" was another, and used a sabre liner wing.
It to was destroyed in a fatal crash most likely
caused by the landing gear deploying at racing speeds.

Presently "Precious Metal" is the only griffon
P-51 that I am aware of.

All these Griffon P-51s are (or were) capable
of 500mph+ at sea level.

But the fastest of all are still Merlin P-51s.
Using hybrid Merlins with Allison rods and superchargers
some have exceeded 530mph unofficially. That's
at sea level in level flight.

Again, these are highly modified P-51s.

Funny thing, the best any Griffon Spit did in air racing
was a third place in the 1947 Cleveland National air races.
it was a XIV, it lost to a FG2-2 super Cosair
and a P-51K. (P-51K is a P-51D with a different prop).

All the planes at the Cleveland races were stock
but over boosted. No fancy areodynamic refinements.

Sergio

DmdSeeker
08-28-2006, 04:43 PM
Interesting link; Hotspace.

Mid mounting the engine would have precluded the aft tank; I presume; and would have cut down on range ( I belive the Griffon was more thirsty than the Merlin??).

I wonder if the MB5 might not have been a better development choice.

It's interesting to see that some think the Malcom hooded B/C was the better plane of the Mustang series. I've somehow got the impression that most of the debate on the Mustang recently on these boards is confined to the D model.

Would anyone here agree (or not!) that "our" B/C model is better than the D? or is the reduction in lethality large enough to negate any handling benefits?

p1ngu666
08-28-2006, 04:49 PM
the malcom hooded ones where the best in terms of speed/handling, plus u could make yourself feel rather odd, because u could look straight down http://forums.ubi.com/images/smilies/16x16_smiley-surprised.gif

hotspace
08-28-2006, 05:12 PM
Originally posted by DmdSeeker:
Interesting link; Hotspace.

Mid mounting the engine would have precluded the aft tank; I presume; and would have cut down on range ( I belive the Griffon was more thirsty than the Merlin??).

I wonder if the MB5 might not have been a better development choice.

It's interesting to see that some think the Malcom hooded B/C was the better plane of the Mustang series. I've somehow got the impression that most of the debate on the Mustang recently on these boards is confined to the D model.

Would anyone here agree (or not!) that "our" B/C model is better than the D? or is the reduction in lethality large enough to negate any handling benefits?

Shame the MB5 never got the break. It would of been one hell of a fighter once the bugs were ironed out http://forums.ubi.com/images/smilies/25.gif

Jaws2002
08-28-2006, 05:28 PM
Originally posted by DmdSeeker:
A Mustang question:

The Mustang was originally a capable but ordinary American plane; made extraordinary by an engine upgrade in the form of the RR Merlin (and it's Packard copies).

That being the case; how come in the fullness of time the Mustang was never upgraded to a Griffon; as was the Spit?

Because there was no need for it. The Merlin powered P-51's were doing great against LW and at that point in time it was clear the war is won. They could have beat Germany even with the P-40 in those numbers at that point in time. Why waste resources in developing a new PISTON ENGINE fighter, when the war is almost over and in few months you'll have tens of thousands expensive, excellent aircraft sent to scrap metal.
Everyone saw what Me-262 could do and knew that in the future the sky will belong to the jets.
The P-51 was great, so was the Griffon, but the future did not belong to them.

gx-warspite
08-28-2006, 06:10 PM
1. Need.

They were unnecessary. The Merlin-powered P-51 did everything the USAAF needed it to do.

2. Cost.

Griffons cost more, and Packard would have to license the engine, which cost more than the Merlin.

3. Production.

Switching production to a new airframe and engine would have cut into P-51 production at a point in the war where it was clear that "more of the same" would win it.

4. Jets.

Why spend millions modifying a fighter to be 20mph faster, shutting down production, re-starting it, licensing a new engine, when you can get fighters 100mph faster off a new assembly line?

5. Philosophy.

The American Way, during WW2, was numbers. Numbers of equipment: artillery, air, bullets, guns, tanks. It was all about leveraging the superior manufacturing ability of America to win the war. It's why America built tens of thousands of Shermans, it's why the US Army (including Patton) fought the upgrade to 76mm guns, because it'd mean a delay in production. The P-51 would be updated if necessary, which it never proved to be.

VW-IceFire
08-28-2006, 06:21 PM
Originally posted by HotSpace:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by berg417448:
The idea was considered. The Griffon engine was going to be mounted behind the pilot the way that the Allison was mounted in the P-39. It never made it past a mock-up.

Yep, you're right there m8:

Click (http://home.att.net/%7Ejbaugher1/p51_8.html) </div></BLOCKQUOTE>
Very cool! Thanks for the link!

fordfan25
08-28-2006, 07:17 PM
because every one knew the p-51 was porked to begain with http://forums.ubi.com/images/smilies/16x16_smiley-tongue.gif

staticline1
08-28-2006, 07:28 PM
It would be kind of interesting how the griffin mustang would compare to the H model. Likewise how would some of you guys compare the P-51H to the later war German props? My guess is pretty well considering its performance.

Bearcat99
08-28-2006, 08:17 PM
Originally posted by DmdSeeker:
A Mustang question:
The Mustang was originaly a capable but ordinary American plane; made extraordinary by an engine upgrade in the form of the RR Merlin (and it's Packard copies).
That being the case; how come in the fullness of time the Mustang was never upgraded to a Griffon; as was the Spit?

Contrary to popular belief... the Mustang was a good aircraft regardless... the Merlin just gave it that uphigh-read in long range escort-capability that the Alison Mustangs lacked. Down low and at medium alt the Mustang was always a competent fighter.

ImpStarDuece
08-28-2006, 08:27 PM
The main advantage the P-51 Mustang had over the Spitfire in terms of speed was its radiator installation, which took full advantage of the boundary layer air and the Meredith effect.

However (insert futile Spitfire defence here), don't forget that there were Merlin powered Spitfires capable of 416 mph and 424 mph (the HF Mk IX/VIII and HF Mk VII). Not as fast as the Mustang most assuredly (and would never be, given the aerodynamic design limitations of the Spitfire), but certainly no slouches in the speed department.

Also, we shouldn't forget the primary mission of the P-51: long-range escort. The Griffon was around 1/3 thirstier than the Merlin for any given range - although the 10-15% higher cruise speed offset that somewhat, the Mk IX range cruised at 220 IAS, the Mk XIV range cruised at around 245-250 IAS - so the P-51 is going to take a hit in range of around 25% if it switches to the Griffon, but its going to get to the target area a little quicker.

p1ngu666
08-28-2006, 08:37 PM
the PR spits may have been really close to p51 speed. ive seen 360mph listed as SL speed for one PR type, and thats in the p51 ballpark

SkyChimp
08-28-2006, 09:08 PM
I'm not sure there was a Griffon that would have given the Mustang better performance than the last model of Packard Merlin installed in the Mustang - the V-1650-9. Additionally, I believe a major redesign would have been required to install a Griffon. All that when the USAAF knew that jets were going to be the way of the future.

As it stood, the P-51H was possibly the best performing late war piston aircraft:

http://www.spitfireperformance.com/mustang/p-51h-64161.html

and at 90" hga

http://www.spitfireperformance.com/mustang/p-51h-altperf-91444.jpg

HellToupee
08-29-2006, 12:10 AM
Griffon engine mustang would have been intersting, tho they boosted up the merlins for later planes eg hornet p51h etc griffon engine could still have received the same treatment.

http://www.spitfireperformance.com/griffonhp_b.jpg

WOLFMondo
08-29-2006, 01:19 AM
Originally posted by Sergio_101:

Funny thing, the best any Griffon Spit did in air racing
was a third place in the 1947 Cleveland National air races.
it was a XIV, it lost to a FG2-2 super Cosair
and a P-51K. (P-51K is a P-51D with a different prop).

All the planes at the Cleveland races were stock
but over boosted. No fancy areodynamic refinements.

Sergio

Might have been a different outcome at 40,000ft, where Spitfire XIV's are more at home!!

Aaron_GT
08-29-2006, 02:39 AM
As it stood, the P-51H was possibly the best performing late war piston aircraft:

The Spiteful (essentially a Spitfire XIV with new wings) would have given it a run for its money at medium altitudes and above (although not at low altitudes). The F.16 (converted from a Spiteful XIV which was a conversion from the Spitfire XIV) could hit 494mph true. Even the slowest version could manage 475mph true (The Spiteful XIV, a direct conversion from the Spitfire XIV). I can check what altitudes those speeds were at, but AFAIK in the region of 20,000 ft.
The Spitfire was never that fast on the deck, though, compared to the P51 or Typhoon/Tempest series, so the P51H would likely beat it down low.

The Spiteful wasn't given much of a priority, though, so all production was post war. The wing famously lived on in the Attacker jet aircraft, much as the Tempest wing also lived on.

Sergio_101
08-29-2006, 03:45 AM
"There Aint No Replacement For Displacement"

That's the old drag racers saying.

True in planes.

But the Griffon has a bit higher frontal
area. That seems to keep it from beating
Merlin P-51s in racing.

In a fighter application there is little doubt the Griffon would have been superior.
over 500mph at critical altitude on a P-51
airframe was nearly a certainty.

No getting around it, P-51s were always faster
than Spits for the same power, despite being heavier.

"Spits are a great war bird, not a good race plane".

Same has held true for Yaks.

But another marrige in reverse, Sea Furys
married to Curtiss Wright R-3350s (From A-1/AD Skyraiders)
are beginning to dominate at RENO.
"There Aint No Replacement For Displacement"
4,500hp on a clean laminar flow airframe
makes up for that fat radial engine.

Sergio

SkyChimp
08-29-2006, 09:12 AM
The F.16 (converted from a Spiteful XIV which was a conversion from the Spitfire XIV) could hit 494mph true.

It certainly had potential. But there was only one F.16 built, RB518, and its 3-stage Griffon engine was prone to failure, and failed time and time again during trials. And while it was fast, it doesn't appears to have had (in my opinion) marked improvement over the last Spitfires, and it didn't climb as well (according to the only figures I have).

Xiolablu3
08-29-2006, 09:40 AM
I owuld think becaue the Mustang didnt NEED more speed, it needed a bit more manouvrability. One of those test pilots comments at the joint fighter conference was 'could possibly lose a little speed and gain more manouvrability'

Wheras the SPit was incredible at manouvres, but lacking a little in speed, the Griffon addition made perfect sense.

The Mustang airframe was incredible at speed but a bit lacking at manouvres, the Griffon would have made it even faster, but even worse at manouvring, because of the added weight.

This is just a guess by the way, I dont exactly know.

Is it possible that the Griffon was a secret British only project? Or did Britian and the USA share everything they had?

WOLFMondo
08-29-2006, 09:54 AM
Forget the Griffon. Look at the Sabre. By the end of the war it was producing more power in operational aircraft than either RR engine, 20% more than the Griffon and it was a smaller displacement. Imagine if the Sabre had the same resources and development time the Merlin did, it might have been producing more power and more reliably than any piston engine, radial or otherwise. Imagine a Mustang with a 3000HP Sabre VA.


Originally posted by Sergio_101:

But another marrige in reverse, Sea Furys
married to Curtiss Wright R-3350s (From A-1/AD Skyraiders)
are beginning to dominate at RENO.
"There Aint No Replacement For Displacement"
4,500hp on a clean laminar flow airframe
makes up for that fat radial engine.

Sergio

The Bristol Centaurus has a higher displacement than R-3350's does it not? 53 ltrs. As I understand more reliable and cheap to maintain with more parts availabe and more people making parts for them and now allot more developed. No ones really used a Centaurus or developed it for an airforce since the late 40's and early 50's unlike the R3350.

Xiolablu3
08-29-2006, 09:55 AM
Wasnt the Sabre far far bigger than the Griffon tho, Wolf? Plus it required that big chin radiator>?

I thought i read something about the next version of hte Sabre getting rid of the chin radiator tho, actually. I forget, maybe one of you guys can correct me on this.

WOLFMondo
08-29-2006, 10:21 AM
Originally posted by Xiolablu3:
Wasnt the Sabre far far bigger than the Griffon tho, Wolf? Plus it required that big chin radiator>?

I thought i read something about the next version of hte Sabre getting rid of the chin radiator tho, actually. I forget, maybe one of you guys can correct me on this.

The chin radiator was just what worked. At least two other working radiators were trialed. One was too complex (annular) and the other was too succeptable to damage (wing mounted).

Circa 1944 Spitfire XIV RR Griffon 65 = 36.75ltr/2080HP/1980lbs dry
Circa 1942 Typhoon Napier Sabre IIA 9lbs 36.7ltr/2180HP/2300lbs dry
Circa 1944 Tempest Sabre IIA 11lbs 36.7ltr/2400HP/2300lbs dry

In 1940 the Sabre was almost twice the power of the Merlin but parliament had allot of RR backers and none representing the upstart Napier. Politics etc.

The IIB produced even more power and at 13lbs produced 2800HP, reliably. Its frontal area was smaller due to the engines shape.

All that with a fraction of RR's budget and resources.

SkyChimp
08-29-2006, 10:24 AM
Originally posted by Xiolablu3:
I owuld think becaue the Mustang didnt NEED more speed, it needed a bit more manouvrability. One of those test pilots comments at the joint fighter conference was 'could possibly lose a little speed and gain more manouvrability'


It got it:
http://www.spitfireperformance.com/mustang/p-51h-64161.html

faustnik
08-29-2006, 10:35 AM
Wow! 450mph! Those power levels were not that high either. http://forums.ubi.com/images/smilies/16x16_smiley-surprised.gif

Xiolablu3
08-29-2006, 10:43 AM
Originally posted by SkyChimp:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Xiolablu3:
I owuld think becaue the Mustang didnt NEED more speed, it needed a bit more manouvrability. One of those test pilots comments at the joint fighter conference was 'could possibly lose a little speed and gain more manouvrability'


It got it:
http://www.spitfireperformance.com/mustang/p-51h-64161.html </div></BLOCKQUOTE>

Yeah I know about that Skychimp, I was just saying that maybe it wasnt worth putting a Griffon in a P51, cos it was so fast already.

The P51H was the lightweight P51 project, I think. The main aim was to get it lighter. They studied the Spit to find out why the P51 was so much heavier.

Could someone answer my earlier question about the Griffon, is it possible that it was secret British stuff and they didnt share it? Or did USA and Brtian share everthing?

Viper2005_
08-29-2006, 10:57 AM
Britain shared everything with the USA. The reverse was not the case (eg P-38s without turbos or handed props. Technology Transfer issues are not new!).

p1ngu666
08-29-2006, 11:03 AM
they probably knew about the griffon, but production of a suitable engine (mostly supercharger related) wasnt until late 43/44

napier engines are a) unusal, and b) effeicent.

projected future engines, the germans where mostly out of ideas apart from sticking 2 engines together, basicaly.

napier had some cunning ideas however http://forums.ubi.com/images/smilies/winky.gif

jets made this a moot point, however

horseback
08-29-2006, 11:09 AM
Originally posted by Viper2005_:
Britain shared everything with the USA. The reverse was not the case (eg P-38s without turbos or handed props. Technology Transfer issues are not new!). That P-38 deal took place before the US entered the war, and the technology behind those turbosuperchargers was considered a state secret. They couldn't legally be given to a foreign power at that time, without the cooperation of a Congress terrified that FDR was going to drag the country into another European war.

The Brits managed to further screw up the Lightning I by specifying that the engines not be 'handed', meaning that the props both turned in the same direction, relieving the aircraft of most of its excellant handling and stall characteristics.

Not long after the Lightning deal, the British were given the B-17C/D, which had the same kind of turbosuperchargers withheld from the Lockheed product.

cheers

horseback

faustnik
08-29-2006, 11:10 AM
Originally posted by Viper2005_:
Britain shared everything with the USA. The reverse was not the case (eg P-38s without turbos or handed props. Technology Transfer issues are not new!).

And the US didn't take enough advantage of that. The UK couldn't build a decent tank before D-Day but, they sure could build great guns with the 17 pounder. The UK/US combo Mustang was the West's greatest all-around fighter, and the Firefly was the best (western) Allied tank to see widespread action. The US should have been building 17 pounders and putting them in their tanks too.

US/UK combos = the good

NekoReaperman
08-29-2006, 11:10 AM
http://www.air-and-space.com/20001008%20Chino/RB-51%2019750618%20l.jpg

*drool*

Sergio_101
08-29-2006, 04:41 PM
Hmmm, the turbosuperchargers were not "deleted".
The Brits wanted their P-38s to have the same engines
and props as their P-39s (some stories say P-40s).
That meant no turbos and no counter rotating props.

The truth is muddled by so many popular press
stories, but it appears the Brits ordered the
"322-60" in a castrated condition, and it sucked
as one might expect.

Sergio

Sergio_101
08-29-2006, 05:09 PM
Bristol Centaurus is a 18 cylinder two row
air cooled radial of 3270 CID.

Slightly smaller than a Wright R-3350 and generally
less powerful it was still an excellent engine
with very good performance.

I did a web search and came up with little about
the attempts to race Sea Furys with a Centaurus.

As I remember there were insurmountable problems
with running the Centaurus at sustained high boost.
Sleeve valve (liners) failures, seisures,and exhaust
port erosion.

In service the Centaurus seems to have been every bit
as reliable as the R-3350. Early versions compared
have the Centaurus as far more reliable!

After the bugs were worked out the Centaurus lost ground
to the R-3350. In it's most powerful form the R-3350
delivers 2,800hp (in a Douglas Skyraider) and 3,700hp
in some transports when turbo compounded.

Advantages of the R-3350 are...

Availability, you can still buy them by the pound (scrap)

Power to weight.

Reliability.

Reliability at racing boost pressures. (easy to get over 4,000 hp!)

Sergio

WOLFMondo
08-30-2006, 06:40 AM
The Centaurus development time and refinement through use isn't really in the same league as those R3350's and similar engines. Weren't some R3350's still in service into the 90's in some US aircraft?

Aaron_GT
08-30-2006, 01:35 PM
More run of the mill Bristol engines were prioritised over and above the Centaurus on the whole, hence the Centaurus development took longer than it could have been, even given its relative level of complexity. And then by the time it was firing on all cylinders (so to speak) it was largely deprioritised as it was anticipated that jets and turboprops (e.g. the somewhat ill-starred Bristol Proteus) were the way of the future. So developmentally it got a bit left out.

In a way it is a bit like the Griffon, the development of which was started in the mid 1930s, and a Griffon Spitfire was proposed (from memory) in 1939. But the Merlin was prioritised as it was working and was sufficient, and the Griffon was put on the back burner to some extent. If it hadn't (and the Spiteful, pretty much in the same camp there) then the 3 stage issue could have been sorted out and a 494 mph debugged Spiteful been around sooner. But the Spitfire IX got a host of minor improvements that kept it going and a main type until the end of WW2, despite the existence of the XII, VIII, XIV, and so on in service during WW2. Even the 21 & 22 were developed during WW2, but weren't really pushed that hard in terms of getting them to the frontline.

There were a plethora of British next generation single engined prop fighter specifications, but manufactures didn't ever seem to give them much priority, apart from perhaps Martin-Baker. In 1940 the priorty was mandated to be existing types with a ban on new development, and then from 1941 the priority was to bring on types then in development and jets, even despite all the messing around with other prop fighter specs. Even the Typhoon and Tempest series was essentially a 1930s design.

Even in the USA the bulk of the WW2 single engined prop fighter types were essentially 1930s designs (ditto Germany), with the exception of the P-51. It's the one that really stands out in WW2, as it was able to take advantage of the latest aerodynamic research, combat experience, and get into service. It took a little while and the Merlin to get the best performance, but it was in service very rapidly with the Allison.

Aaron_GT
08-30-2006, 01:38 PM
After the bugs were worked out the Centaurus lost ground
to the R-3350. In it's most powerful form the R-3350
delivers 2,800hp (in a Douglas Skyraider) and 3,700hp
in some transports when turbo compounded.

The final versions of the Centaurus managed 3000hp, so it is comparable to what the Skyraider had. As I mentioned in the other post, though, the Proteus was what Bristol was looking towards (and Rolls Royce similarly, after it abandoned the Eagle 2). There was talk of using Centaurus in some post-war flying boats due to it being less thirsty than a turboprop, but then the Napier Nomad was considered some to be better as it was even more economical with fuel.

Viper2005_
08-30-2006, 01:55 PM
And it would run on almost anything...

Sergio_101
08-30-2006, 04:16 PM
There are a number of DC-7s still earning a living.
As far as I know this is the only R-3350 powered
aircraft still commercially viable.

In the non passenger class there are many Lockheed Neptunes
flying as fire bombers powered by the R-3350.

The DC-7C is powered by turbo compounded engines.

Yes, I am aware that there were versions of the
centaurus rated to over 3,000hp.
I know of no applications that used them.
I'll bet you will point one or two out....

Last US military combat plane using the R-3350 was the
Lockheed Neptune, they were turbo compounded.


Sergio

Kurfurst__
08-31-2006, 02:53 AM
Originally posted by p1ngu666:
projected future engines, the germans where mostly out of ideas apart from sticking 2 engines together, basicaly.

Ts-ts. DB 603 N. http://forums.ubi.com/images/smilies/winky.gif

Sergio_101
08-31-2006, 03:41 AM
Germans built a plethora of huge radials
and banked aircraft engines. Trouble
is they were all to late to be developed
and see service.

Even the huge American P&W R-4360 failed
to get into combat despite being a late
1930's project.

Was the DB-603N not the Benzine burning
speed record attempt engine?

Back to the Americans, the Allison V-3420
was a twin Allison V-1710 design.
It proved reliable but never ot into
a production aircraft. (2600-3000hp depending on model).

After the war the Brits twinned the Bristol Centaurua
in the white elephant "Bristol Brabazon".

Still the largest aircraft engine ever attempted
was the Lycoming XR-7755.
36 cylinders, 7755 cid, water cooled, 5,000hp
in the prototypes.
This was to power the B-36, but the jet age
dealt it the death blow. Only two were built.
These prototypes were test run at Wright Patterson.
A quote from a test engineer "It started and ran
like a V-8 Caddilac".

Sergio

WOLFMondo
08-31-2006, 03:51 AM
The Napier Sabre was essentially two engines, one mounted on top of the other.


Originally posted by Aaron_GT:
Even the Typhoon and Tempest series was essentially a 1930s design.


I'd agree and disagree on this. The Typhoon had some left overs from the Hurricane in its design but the series II Tempest V's were had allot of refinements like the high speed controls, completely new electrics and hydraulics, laminar flow wing, great attention to aerodynamic properties etc. The Fury took it even further.

Kurfurst__
08-31-2006, 04:09 AM
Originally posted by Sergio_101:
Was the DB-603N not the Benzine burning
speed record attempt engine?

Nope (I guess you mean the 601R race engines that set the world record in `39). It's true that the Germans had quite a few unorthodox designs in their mind, but these tend to overshadow the existance of their common designs.

The 603N was development of the 603LA (see Do 335), basically a 44.5 liter, two-staged intercooled, V-12 quite similiar to the DB605 in appearance and dimensions. The 603 series appeared in 1943, fitted in various to ME 410s, Do 217s, Do335 and in general quite similiar to the story with the Griffon. Projected output of the 603N was 2750 PS at SL, and 1950 PS at 11 000 m (36k ft !!!) rated altitude, at 2.0ata and 3000rpm.

luftluuver
08-31-2006, 04:29 AM
Aaron_GT, the Griffon was also a RN engine. By this, I mean it was developed for RN FAA a/c useage.

luftluuver
08-31-2006, 04:30 AM
The Griffon was never developed to the extent the Merlin was.

Didn't some Reno P-51 racers get Griffon engines?

Aaron_GT
08-31-2006, 05:14 AM
Aaron_GT, the Griffon was also a RN engine. By this, I mean it was developed for RN FAA a/c useage.

At the end of the 1930s it was already one of the sometimes bewildering array of engines that were offered in alternatives for strictly ground based aircraft, along with the Vulture, Sabre, Dagger, etc, etc. So it quickly was seen as an engine to be applied outside the naval arena. It just didn't receive as much effort in the 1939-41 period as it was more expedient to work on the Merlin, plus effort was wasted on the Peregrine and Vulture.


the series II Tempest V's were had allot of refinements like the high speed controls, completely new electrics and hydraulics, laminar flow wing, great attention to aerodynamic properties etc. The Fury took it even further.

Very true, but the Tempest was originally still half a Typhoon, in that the fuselage is very very similar, and it was nearly named the Typhoon II. So apart from the wing is still has a strong late 1930s heritage. The Fury's beginning to be much more of a 1940s development as the changes really mount up. At what point you draw the line during a progressive development is probably a philosophical one! It's evidence, though, for how long aircraft development, even during wartime, could take, which makes the P-51 even more remarkable.

Sergio_101
09-01-2006, 03:11 AM
Using America's entry into WWII as a startpoint, very few new designs of anything
including combat aircraft got used in numbers
during WWII.

WWII was fought with pre 1940 tech.

exceptions were, in the US, the F6F Hellcat,
Boeing's B-29, Northrops P-61 black Widow,
Germany's Messerschmitt 262,
Britan's Gloster Meteor.

There were others I'm sure.
That's what I could think of quickly.

As to sharing bit's and pieces, the legendary
B-17 was a development of the Boeing 247 airliner!
Add two more engines and give it a strech.
They shared many components, same type
of structure and outer wings.

Douglas B-18 was a militarised DC-2.

Hard to find a German bomber that was not a
mail plane or airliner in the 30's.

Sergio

Kurfurst__
09-01-2006, 10:49 AM
Originally posted by Sergio_101:
Hard to find a German bomber that was not a
mail plane or airliner in the 30's.

Sergio

I'd rather say it was quite hard to find a German airliner in the 1930 that was not a disguised bomber, or a German 'courier' plane that was not a fighter. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

p1ngu666
09-01-2006, 10:58 AM
i think it was the do17 that was orignaly itended for passenger aircraft, and the design wasnt intended for miltary use. the amusing thing about that is, its the worst civil plane of the lot http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif

the blehium was also first a civil aircraft, and damn quick for the time http://forums.ubi.com/images/smilies/16x16_smiley-surprised.gif

WOLFMondo
09-01-2006, 11:15 AM
Originally posted by Aaron_GT:

Very true, but the Tempest was originally still half a Typhoon, in that the fuselage is very very similar, and it was nearly named the Typhoon II. So apart from the wing is still has a strong late 1930s heritage. The Fury's beginning to be much more of a 1940s development as the changes really mount up. At what point you draw the line during a progressive development is probably a philosophical one! It's evidence, though, for how long aircraft development, even during wartime, could take, which makes the P-51 even more remarkable.

The Series I used some Typhoon parts but the Series II was very different in many respects, including its fuselage. The Seafury was just a Tempest II with the inner wing section removed, the cockpit raise and a new rudder.

BigKahuna_GS
09-01-2006, 01:10 PM
__________________________________________________ _____________________________________________
Britain shared everything with the USA. The reverse was not the case (eg P-38s without turbos or handed props. Technology Transfer issues are not new!).
__________________________________________________ _____________________________________________


Lockheed advised the Brits to order the P38 as is and warned that engine power reductions along with prop handing changes would nullify the great no torque flight qualities the fighter was known for. As it was the Brits wanted a cheaper version with parts that could be interchanged with other aircraft. Lockheed called the Brit version the "castrated 38". The Brits considered
replacing the non-turbosupercharged Allisons with supercharged Merlins to increase power and engine nacelle streamlining. Prop handing with Merlins was possible but not likely for the Brit version. Kelly Johnson had a complete P38 Merlin test bed ready and waiting for the Merlin engine swap. A behind the scenes political infighting took place as General Motors wanted the rights to US built Merlin engines for their own fighter project the XP-75 for which they thought they could clean up on both ends by producing both a fighter and the aircraft engines for it. That meant no Merlins available for P38s as GM saw their futere fighter design recieveing Merlins.

The P75 was a conglomeration of pre WWII aircaft styles and engineering which turned it into the worst at everything catogry and a complete failure in terms of time, money and resources that could of been better spent on more worth while projects. GM also lost the Merlin lincense to Packard which was fitting for the millions of dollars they wasted on a turd of a fighter design. The loser in all this was the P38, the Brits and US P38 pilots. In an email from Warren Bodie, Kelly Johnson encouraged the British Merlin engine swap and his vision was for the P38L to be Griffon powered. A P38L with nearly 5000hp total. The P38K design in 43' would of had Allison turbosupercharged of 4100hp total and paddle blade props which increased both speed and climb rate. This design was killed by the War Production Board so as not to slow P38 production.
http://aerofiles.com/fisher-p75a.jpg



__________________________________________________ _____________________________________________
Faust-And the US didn't take enough advantage of that. The UK couldn't build a decent tank before D-Day but, they sure could build great guns with the 17 pounder. The UK/US combo Mustang was the West's greatest all-around fighter, and the Firefly was the best (western) Allied tank to see widespread action. The US should have been building 17 pounders and putting them in their tanks too.

US/UK combos = the good
__________________________________________________ ______________________________________________


Agreed
US tank design was centered around US Army infantry support philosphy. The Sherman was an infantry support tank first and formost. Even though the Sherman was having a tough time with penetrating Panther & Tiger tank armor, US Army generals were relunctant to upgrade the Sherman's 75mm standard gun. The reason for this poor decision was that infantry commanders feared that Shermans with improved armor and 90mm guns would go Panther & Tiger hunting and
neglect their primary responsibility of infantry support.
http://www.wwiivehicles.com/usa/tank_destroyers/m18/m18_02.jpg
The Sherman was to stay with the infantry and Tank Destroyers like the Wolverine & M18 Hellcat were to engage and destroy heavy german armor utilizing superior speed, mobility & a 76mm long barrel cannon. The Hellcat tank destroyer could do 50-55mph and was lighty armored. The Hellcat was successful in destroying heavy german armor but it's drawbacks were there was not enough to go around and being lightly armored was knocked out easily.

Finally both infantry and armored generals woke up and realised that reguardless of the infantry support role individual tank companies should be able to defend themselves and destroy the threat of heavy german armor without having to call for additional specialized resources such as Tank Destroyers. A heavy battle tank was designed and bulit but took too much time.
The stop gap was for the Shermans to be up gunned to 76mm long barrels and eventualy to 90mm cannons with improved armor and a safer interior ammo storage design. The US heavy tank was the Pershing and was capable of meeting and beating the best german tanks 1v1. Think of all the Sherman tank crews that could of survived had this decision been made early in the war. The rule of engagment was that it took 5 Shermans to knock out 1 Tiger tank. The Russians understood what needed to be done early on and built thier own series of heavy tanks to counter german designs.
http://www.tanksintown.be/TIT%202003%20PERSHING%201.jpg
T-26 Pershing 42tons 90mm gun
It quickly became clear that the tank destroyers doctrine failed in the field and that the upgunned Sherman was still unable to engage the Panther on more or less equal terms. Unfortunately, about half of the German tanks in France were Panthers. Efforts were made to speed up the development, but the tank, by now called the T26 and dubbed Pershing, only reached the battlefield after the Battle of the Bulge and saw little action in WW2.

Overall, the Pershing was considered roughly equal in performance to the Panther. In the first engagement with the M26 by the 3rd Armored Division, Cooper writes that the M26 managed to catch two Tigers and one Mark IV tank by surprise from a flanking position. The M26 engaged the tanks from a range of about 1000 yards (1 km), and knocked them out. Cooper asserts, "It is doubtful that the M26 could have knocked them out had the Tigers been confronted with a frontal assault. Our M36 tank destroyers, with the same 90 mm gun, had difficulty penetrating the Mark V Panther's faceplate."

Two M26A1E2 tanks were built during the Second World War. One of these made it to the ETO, assigned to the 3rd Armored Division. This experimental version of the Pershing, sometimes referred to as "Super Pershing" (as are other upgunned Pershing variants), had the 90 mm/70 caliber T15E1 high-velocity gun that threw a projectile at 3,850 ft/s (1,173 m/s). On April 4, 1945 near Dessau, the "Super Pershing" destroyed one King Tiger by striking its underbelly and knocked out another tank, probably a Panther, with a shot to its flank [2]. However, that was its only known combat engagement. Thus, the full capabilities of the T15E1 90 mm main gun were never demonstrated.

_

Abbuzze
09-01-2006, 01:34 PM
Why the Mustang was never intended to be fitted with a Griffon?

The answer is simple. It would destroy what the Mustang made so great, more fuel consumption - less range. Bigger engine - bulges, so less aerodynamical effective. More weight - worser wingload at a plane with allready high wingload. It was simply not a good idea.

faustnik
09-01-2006, 01:35 PM
Originally posted by 609IAP_Kahuna:"It is doubtful that the M26 could have knocked them out had the Tigers been confronted with a frontal assault. Our M36 tank destroyers, with the same 90 mm gun, had difficulty penetrating the Mark V Panther's faceplate."

With the 17 pounder, the US would have a gun very capable of taking on the German tanks headon. The M4/75 could barely cope with a late MkIV.

The flanking tactics used by the tank destroyer arm were good, but, even the 76mm M1A1 was not a very good gun. The Achilles was a much better TD than the Wolverine.

The US had access to one of the best AT guns of the war and just didn't take advantage of it. http://forums.ubi.com/images/smilies/51.gif

Aaron_GT
09-01-2006, 02:27 PM
The Series I used some Typhoon parts but the Series II was very different in many respects, including its fuselage.


I thought the changes were limited to the rear spar pickup (changed from tubular on the remanufactured Typhoon fuselages typically used in Tempest series I to cast in series II) and the elimination of tail fishplates in series II?

Sergio_101
09-01-2006, 02:30 PM
Ok, the story about Merlins for the failed Fisher P-75
can not be true. The P-75 was designed around the
Allison V-3420 with extensionn shafts like a P-39.
Since Allison was and is a division of General Motors
I sincerly doubt that GM would want to put a
Packard product in the P-75 in place of the V-3420.

What GM was upset about was the possability of loosing
the Alison contract for the P-38. Two engines
each and spares meant loosing the contract
for around 30,000 engines!

Besides, the Merlin would have gained little or nothing
in the P-38. Allisons were very good and made
excellent power with turbocharging.

The primary reason the Merlin worked so well
in the P-51 was that the Allison had only a single stage
single speed gear driven supercharger.
Altitude performance suffered.

Later Twin Mustangs got the Allison in a two stage
design and performed very well.
The last prototype P-51, the P-51J also had this
late Allison design.
The bugs were never ironed out in the J model
but there is a bunch of press saying it was
capable of 500mph.

Allisons were not bad, it's just that they
were limited by the USAAC/USAAF insisting
on turbocharging. A two stage Allison was developed
but it was late and saw limited service during WWII
in the P-63.

Want a "what if?" or more accurately a "Why not!"
The P-38K, little more than a P-38J/L with new props.
The performance was stunning! Time to climb and all around
performance improved in dramatic fasion!

sergio

Sergio_101
09-01-2006, 02:36 PM
Originally posted by faustnik:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by 609IAP_Kahuna:"It is doubtful that the M26 could have knocked them out had the Tigers been confronted with a frontal assault. Our M36 tank destroyers, with the same 90 mm gun, had difficulty penetrating the Mark V Panther's faceplate."

With the 17 pounder, the US would have a gun very capable of taking on the German tanks headon. The M4/75 could barely cope with a late MkIV.

The flanking tactics used by the tank destroyer arm were good, but, even the 76mm M1A1 was not a very good gun. The Achilles was a much better TD than the Wolverine.

The US had access to one of the best AT guns of the war and just didn't take advantage of it. http://forums.ubi.com/images/smilies/51.gif </div></BLOCKQUOTE>

I saw a film of a US Pershing stalking and killing a Panther in Cologne.
The Germans did their best to avoid the Pershing crew.
The end was anticlimatic as it was more sad than victorious.
The Pershing destroyed the Panther with a single shot
and the German crew burned to death.
Pershings had a high velocity 90mm gun.
Seems to me it did the job easily.

Sergio

Kurfurst__
09-01-2006, 02:42 PM
The Cologne story/footage is not about stalking iirc, a Panther was 'playing dead' near the Great Dom, and suddenly opened fire on some Shermans - knocking out two iirc from surprise. Then a M26 that followed them returned fire and knocked it out.

Obviously it was a very short range engagement, given the footage. That camerman was shooting that Panther burning and receiving hits from like 20 meters...

WOLFMondo
09-01-2006, 03:14 PM
Originally posted by Sergio_101:

Besides, the Merlin would have gained little or nothing
in the P-38. Allisons were very good and made
excellent power with turbocharging.


The Merlin didn't require those fat heavy turbochargers in the booms. The weight saving would have giving the Merlin some advantage...or additional fuel space.


Originally posted by Aaron_GT:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">The Series I used some Typhoon parts but the Series II was very different in many respects, including its fuselage.


I thought the changes were limited to the rear spar pickup (changed from tubular on the remanufactured Typhoon fuselages typically used in Tempest series I to cast in series II) and the elimination of tail fishplates in series II? </div></BLOCKQUOTE>

I think that was the case. The Series I's had problems with the tail sections because of the changes to the fuselages but the series II's with there specifically built fuselages didn't have these issues which also ment the tail sections were detachable as previously designed.

luftluuver
09-01-2006, 03:32 PM
There was another reason the Sherman did not get replaced. That was because of shipping and unloading concerns besides that production was already in full go mode. In a Liberty ship, 5 Shermans could be carried for every 3 T-26s.

Abbuzze, so a Griffon P-51 would have slight bulges like the Spit XIV. A Griffon had a frontal area ~5% larger than a Melin. The extra weight would balance the full 85gal fuselage tank. Besides the Griffon might have forced NAA to extend the fuselage, like they did on the P-51H, sooner. Tail wagging disappears. The Griffon gave the Spit XIV a top speed some 30mph faster than the Spit IX dispite the larger rads and nose bulges.

The biggest problem would have been setting up the manufacturing line for the Griffon in the USA.

On range. What was the fuel consumption for a Merlin P-51 at 425mph? The Griffon would not have to be run as hard to do 425mph, thus using less fuel.

luftluuver
09-01-2006, 03:35 PM
On the Merlin P-38s. A study was done and there was no real advantage over the turbo Allison powered P-38s.

Viper2005_
09-01-2006, 03:51 PM
I would be very interested in seeing that study.

berg417448
09-01-2006, 04:11 PM
The only negatives I remember for a merlin powered P-38 were supposed to be a lesser rate of climb and a lesser service ceiling. Well...there would also be the need for a re-design...IIRC they said that you could not just drop a merlin in the space designed for the allison

Sergio_101
09-01-2006, 04:16 PM
Kurfie, I saw that film many times, it runs for about 5 minutes
in it's unedited form. Where are the Shermans?
I saw the Panther make no shots.
Also, the range (not that it really matters) is closer to 100M.
After one round of 90mm the Panther stopped and began to burn.
It looked like one of the crew tried to bail and got caught by an explosion.
Perhaps it was just the hatch popping open by the force of the blast.

As to the study about Allison vs Merlin powered P-38s.
Yep, that's the result, no gain and some loss way up high.
yes, Merlins would have opened up some space and may
have performed better at some altitudes.
Turbocharged engines have no stepps in the horsepower from
switching blower gears and stages.
Turbocharged engines also don't suffer from parasitic power loss
from driving a high blower ratio and or a two stage blower.

A Allison as installed in a P-38 made pretty close to the same
power from sea level to critical altitude, 28,000 feet.

Sergio

berg417448
09-01-2006, 04:31 PM
According to this there was a Sherman knocked out first:

http://home.earthlink.net/~crcorbin/Smoyer.html (http://home.earthlink.net/%7Ecrcorbin/Smoyer.html)

Sergio_101
09-01-2006, 04:47 PM
Originally posted by berg417448:
According to this there was a Sherman knocked out first:

http://home.earthlink.net/~crcorbin/Smoyer.html (http://home.earthlink.net/%7Ecrcorbin/Smoyer.html)

And three shots were fired, the first obviously knocking the tank out.
Funny that the "weak" 90mm gun pissed through BOTH
sides of the Panther!!!

That obviously was the crew bailing in the movie, they died there in the street.

I stand corrected, a Sherman was shot.
But it is not in the film.

Kurfy, one Sherman was shot..... Not "some Shermans" or " knocking out two iirc from surprise".
But your tendency to exaggerate is legendary.

Oh yea, note that the M-26 was called in for help.
You imply it was attached to the Shermans and ambushed the Panther.

It was a superior American tank blasting a inferior
German design, plain and simple.

Sergio

DIRTY-MAC
09-01-2006, 06:10 PM
SPITSTANG SUCKS, EVERYBODY KNOWS THE FUUCKER WON THE WAR http://forums.ubi.com/images/smilies/53.gif

Xiolablu3
09-01-2006, 07:00 PM
Originally posted by luftluuver:
On range. What was the fuel consumption for a Merlin P-51 at 425mph? The Griffon would not have to be run as hard to do 425mph, thus using less fuel.

Not sure exactly, but I remember reading that the Griffon Spit XIV range was about the same as a MkIX because although it used more fuel - it cruised faster

The-Pizza-Man
09-01-2006, 07:39 PM
It also had a bit more fuel as well.

Sergio_101
09-02-2006, 01:16 PM
Bump

Kurfie, where are you?


Sergio

Aaron_GT
09-02-2006, 03:49 PM
On the Merlin P-38s. A study was done and there was no real advantage over the turbo Allison powered P-38s.

There probably would have been advantages. The decision not to proceed with Merlins was taken before the problems with the P-38 at high altitude were discovered, and a Merlin P-38 was avoided. It would also have boosted speed at some altitudes. When the high altitude shortcomings on the Allison installation were discovered it was deemed not worth the massive loss in P-38 production changing to a Merlin version. It was probably the right decision as the P-38 was desperately needed at the time and the improvement with Merlins probably would have mostly been in the area of reliability rather than performance.

Aaron_GT
09-02-2006, 03:52 PM
As to the study about Allison vs Merlin powered P-38s.
Yep, that's the result, no gain and some loss way up high.


Careful there. With Merlin XX, some loss at altitude would be expected. But there were numerous versions on the Merlin with different outputs and different performance at different altitude. A Merlin 70 at high boost would be a different kettle of fish to the relatively early Merlin XX, which was the basis of the original study. It would be like comparing the performance of the Mosquito FB.VI with the Merlin 23 or whatever it is we have in game with what the FB.VI had by the end of the war.

Aaron_GT
09-02-2006, 03:54 PM
Funny that the "weak" 90mm gun pissed through BOTH
sides of the Panther!!!

What would you expect at such short range? The Shermans should be able to take out a Panther at that range too.

Aaron_GT
09-02-2006, 03:56 PM
It also had a bit more fuel as well.

It was quite a bit heavier overall, which some felt had a negative effect on its flying qualities, making it not really a Spitfire. But then the trend was to faster, heavier aircraft through the war, so it fitted with the general trend.

Kurfurst__
09-02-2006, 04:00 PM
Originally posted by Aaron_GT:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">On the Merlin P-38s. A study was done and there was no real advantage over the turbo Allison powered P-38s.

There probably would have been advantages. </div></BLOCKQUOTE>

I seriously doubt. The airframe was given, twin boom, large twin engined fighter. Into those conditions, a turbocharged engine was a good solution. The turbocharged Allisons in the P-38 easily competed or bested with any of the Merlins in altitude performance, gave a stage-less power all up to the rather decent rated altitude, and the turbos generally meant good economy, and the powerplants were quite light btw.

luftluuver
09-02-2006, 04:41 PM
Originally posted by Kurfurst__:
and the powerplants were quite light btw.

V-1710 G6R/L (V-1710-143/-145)

1,595 lbs

V-1650-9

1,690 lbs

A big 100lbs difference and the GE turbos would have cancelled that difference out.

http://www.unlimitedexcitement.com/

p1ngu666
09-02-2006, 04:53 PM
merlins sound better than allisons.

therefor, merlin wins http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif

LStarosta
09-02-2006, 05:04 PM
I'd rather date a gal named Allison than Merlin... http://forums.ubi.com/images/smilies/winky.gif

Sergio_101
09-02-2006, 05:15 PM
At an airshow I got to hear numerous
flybys by a P-40K and a P-51D.

That Allison sounded way better IMO.

Sergio

Viper2005_
09-02-2006, 05:21 PM
Not a fair comparison since the Allison was the name of the company. V-1710 was the name of the engine. Which means you should ask yourself, would it be more weird to go out with a girl called V-1710 or a girl called Merlin? And if you answered the latter, Merlin was also known as V-1650 which is IMHO a nicer number. But you'd still be weird...

Getting back to a less surreal version of reality...

The Merlin gave a substantial quantity of exhaust thrust, which is very important at speeds >350 mph or so. At high speeds it should out perform the V-1710 substantially.

AFAIK the P-38 stayed with the V-1710 for political reasons; Allison had to be kept in biz.

Of course, today, RR owns Allison. You can't buck the markets...

WWMaxGunz
09-02-2006, 05:54 PM
Packard licensed to make Merlins as in paid fees.
They tooled and trained workers to build Merlins, many of them, engines and workers.
What improvements they made....
And that's without any changes to the airframes, those production lines and workers.
Once you get going on production you keep going unless shortages slow you down.

It might have been nice to make further improvements but the gain would have had to been
greater than 10% to offset the cost.

I would have been better to spend effort on the tanks but then they did ith the longer 76mm
guns and other improvements such as the gyro-stabilized gunmounts and the later up-armored
Shermans though there are limits to what you can ask of engines and transmissions. Even the
Tigers and King Tigers suffered drivetrain problems as well as the too many parts problems.
By the time the US got tanks produced and clear onto the scene though, it was like what was
okay at design time was outdated in the field. The designers did not take delivery into
consideration, it seems.

Oh well, just add more 155's and 8" guns! They don't stop working because the clouds rolled
in!

Sergio_101
09-02-2006, 06:20 PM
Exhaust thrust is a very inefficent way to
use that potential power, not an opinion, it's a fact.
Using that power to drive a turbocharger is
a better way, saves 400+hp.
Turbo compounding is also effective, but
no compounded engines reached service
during WWII.

After WWII Allison demonstrated that up to 800hp
was recoverable from a V-1710!

Wright developed the only turbo compounded engine
to reach production, the R-3350TCW series of radials.
Up to 1,000 hp was recovered by the turbines!

Strange that no turbocharged Merlins got into a plane.
I am aware that RR did some research, may have run
a test engine or two????

Sergio

WWMaxGunz
09-02-2006, 09:42 PM
Props lose efficiency with speed while gas jets do not.
With the engines they had in WWII there were already wide props that allowed more power to
be used less efficiently and they had about reached limits with those.
You can only spin the prop so fast and then the tips hit mach between spin and forward motion.

Of course if you are talking about power for climb and sustained turns then yeah more is more.
But you put the load on the big engine and you need the bigger fuel tank too.

Aaron_GT
09-03-2006, 02:23 AM
Strange that no turbocharged Merlins got into a plane.

Most of the aircraft that received Merlins either had no space for the required equipment or had no particular need for it. So given that there was no imperative to produce a Merlin with turbocharging not a great deal of effort was expended on it. At the point where the additional power might have been useful the writing was on the wall for the piston engine and Rolls Royce was swapping its efforts to jets and turboprops.

If you look at the P-47, it was essentially built around its turbocharger, and the P-38 had space in the booms for it. The Spitfire couldn't have accepted one, nor could the Mosquito, and the Lancaster didn't generally operate at an altitude that required turbocharging. Some investigation was done into a high altitude Lancaster using a slave engine as a compressor, but it was a low priority project, not enough to get RR to develop a turbocharger as an alternative, which in any case would have required additional redesign of the Lancaster above and beyond the planned pressure cabin.

p1ngu666
09-03-2006, 06:58 AM
the merlin series engines that ended up in Ix's and p51's etc, the devlopment process was started intending tobe turbocharged, but stanley ****** felt supercharging and exhaust thrust was better. this was for orignaly a high altitude wellington btw http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif

Viper2005_
09-03-2006, 08:56 AM
Originally posted by Sergio_101:
Exhaust thrust is a very inefficent way to
use that potential power, not an opinion, it's a fact.
Using that power to drive a turbocharger is
a better way, saves 400+hp.
Turbo compounding is also effective, but
no compounded engines reached service
during WWII.

After WWII Allison demonstrated that up to 800hp
was recoverable from a V-1710!

Wright developed the only turbo compounded engine
to reach production, the R-3350TCW series of radials.
Up to 1,000 hp was recovered by the turbines!

Strange that no turbocharged Merlins got into a plane.
I am aware that RR did some research, may have run
a test engine or two????

Sergio

Actually, that's certainly opinion.

At 375 mph 1 thp = 1 lbf.

Of course since prop efficiency is only about 80%, this means that at 375 mph 1 bhp = 0.8 bhp.

At 450 mph at 80% prop efficiency, 1 bhp = 0.67 lbf.

Or to put it another way, 1 lbf = 1.5 bhp.

The faster you go, the more efficient exhaust thrust becomes. The beauty of exhaust thrust is that you just need a set of short pipes to realise it.

Turbocompounding OTOH requires a complicated, heavy and expensive turbine (or turbines) and some interesting gearing.

Turbocharging allows you to swap gearing for a compressor, but it's still quite complicated.

Both effectively serve to provide you with extra bhp (since the turbocharger removes the need to subtract shaft power to drive a supercharger).

OTOH, they remove exhaust thrust. And the increase exhaust back pressure, which tends to hurt scavenging.

The Merlin didn't use an exhaust turbine because it was fundamentally a fighter engine, and exhaust turbines don't stack up that well for the high speed fighter mission.

I can see a strong case for the bomber mission, but of course that would have greatly complicated development...

Sergio_101
09-03-2006, 03:44 PM
http://www.enginehistory.org/v1710tc.htm

http://www.enginehistory.org/Allison/V1710TC.jpg

Good short artical about turbo compounding.'

Sergiohttp://www.enginehistory.org/Gallery/Lofthus/R-3350_3.jpg