Waste of a good engine/crying out for a better engine

[davebender]

No argument there. Especially since 960hp BMW 132 was already in production and it was dirt cheap compared to most other German aircraft engines.

 

[Shortround6]

How many times do we have to tell you that the BMW 132 was too big and too heavy to be "plug in" replacement for the the Gnome-Rhone M ?

Ye, you could make a ground attack twin using BMW 132 engines but it would have very few parts in common with the HS 129 no matter what you call it.

BMW engines are about 250lbs heavier EACH, need bigger, heavier propellers, have a diameter of 54.3 in compared to 37.4in Frontal area of 16.0 sq ft compared to 7.6 sq ft.

You want to add 600lbs or more how many feet in front of the CG?

Can you fit a bigger propeller without moving the engines outboard on the wing?

Unless you change the thrust line the top of the cowl will about 8 in higher than with the French engines, restricting side vision.

How much drag did you add to the plane? each BMW having the frontal area of BOTH Gnome-Rhone engines.

 

[merlin]

I think the Bristol Blenheim is an aircraft that would have been better with something more powerful than the Mercury. It was a good aircraft in the 30s, but after that 'easy-meat'.

 

[Aozora]

I think the Bristol Blenheim is an aircraft that would have been better with something more powerful than the Mercury. It was a good aircraft in the 30s, but after that 'easy-meat'.

Unfortunately there were no real alternatives to the Mercury available; fitting Merlins was never considered, and probably wouldn't have improved things much anyway, particularly in the semi-suicidal missions the Blenheims carried out in France. One plan put forward in 1939 was to use Taurus engines, as fitted to the Beaufort, but Bristol was having enough trouble building them, let alone building enough reliable Taurus' for the Beaufort.

When Bristol did go ahead with a Blenheim redesign, incorporating more powerful Mercurys, more armour and better armament, the result was the abysmal Mk V, which weighed in at 17,500 lbs full load cf the Blenheim I at 12,000 lbs...

 

[Civettone]

Used in production aircrafts: A.80, P.XI, P.XII, P.XIX, Ra.1000, Ra.1050, AR 128.
Homologated, but used in aircraft prototypes only: AR 135, A.82, P.XVII, Zeta.

I said 'reliable' engine. The A.80, P.XI, P.XII and P.XIX were all unreliable. The licence produced DBs do not count. The AR.128 produced almost 1000 hp, so I will correct my statement to no reliable engines over 1000 hp.

Fairey Fulmar was in need for more engine power, ditto the Firefly (rectified once two stage Griffon was installed). Spitfire could've used more HP, from time after BoB until the 2-stage Merlin entered service. Fw-190 and Bf-109 needed more power in 1944. Albacore needed, say, Twin Wasp, ditto for the Beaufort? French airplanes needed more HP, too.

As soon as I saw this thread, I thought of you, Tomo. I am sure you could come up with two dozen of re-engined aircraft proposals!

How many times do we have to tell you that the BMW 132 was too big and too heavy to be "plug in" replacement for the the Gnome-Rhone M ?

Ye, you could make a ground attack twin using BMW 132 engines but it would have very few parts in common with the HS 129 no matter what you call it.

Why not put a DB 606 there while you're at it

Kris

 

[GregP]

For the Hs 129, too bad they didnlt have a supply of Shvetsov ASh-21 radials. At 700 hp and 1,024 pounds,it would have been just what was needed. 100 more hp each at only a tiny weight penalty.

 

[Civettone]

The Hs 129C was going to be the ultimate Hs 129. Armed with 2 30 mm cannons, a bomb load of a 1,000 kg and powered by two 800 hp Isotta Fraschini Delta engines.


Kris

 

[nuuumannn]

nobody seems to be able to point out what problems the Peregrine actually had, At least as far as reliability or durability.

This has been covered in another thread, but I can't be bothered looking, so I'll post from Rolls-Royce - The pursuit of excellence by Alec Harvey-Bailey and Michael Evans;

"Contrary to popular belief, the Peregrine was not unreliable. Its two main problems were rapidly tackled. Main engine joint failures were overcome by deleting the joint washers and using jointing compound, while bowstring failures of end cylinders holding down studs were cured by reducing anti-vibration collar clearances. Some of the stories of unreliability spring from difficulty in managing the operation of the radiator shutters during taxiing, take-off and initial climb. Westland had linked the radiator shutter operation with that of the aircraft flaps, so that there were times when the pilot had to use flaps to keep the radiator shutters open, when flaps were not needed in flight. In early operations a number of engines were overheated because the system was not fully understood, and evidence of this is in the pilot's notes, which were extensivelt amended."

Fairey Fulmar was in need for more engine power

I think re-engining the Fulmar, Albacore and Blenheim for that matter was a waste of time; the performnce gain would have been negligible and certainly would not have done anything to change the combat capabilities/fortunes of these types.

The Manchester is a good example of what happens when re-engining of a good airframe goes right. I'm surprised no-one's mentioned the He 177 yet.

 

[altsym]

Rolls-Royce Crecy had massive potential.

 

[GregP]

Never heard of a reliable Isotta Fraschini engine ... anywhere.

 

[GregP]

Never heard of a reliable Isotta Fraschini engine ... anywhere. Aero engine, that is ...

 

[Dogwalker]

I said 'reliable' engine. The A.80, P.XI, P.XII and P.XIX were all unreliable.

They were not. Only the A.80 had manteinance (but not not breakages) problems, similar to that of the BMW801 to name one, that were not resolved during its production (and also in this case should be reported that the Japanese, who used them on Br.20s, had several complaints concerning the aircraft, but none on the engines). Of the others, only the first samples can be considered problematic. The P.XII, for example, has been free, from the outset, by problems of breakage, vibrations and overheating, that, for a completely new engine, is almost a record. It showed some carburetion problems on the Z.1018 prototype and on the first samples of P.108, but they were working on a new aircraft with the first units produced of a new engine. I do not think that the first twenty or thirty samples of any high power radial produced during WWII, have been much more reliable. In general, the Regia Aeronautica did not order for the mass production an unreliable engine, though certainly mechanics would have preferred all them to be stone-axe reliable as the A.74.

The licence produced DBs do not count.

You said "produced", not "designed", so they count.
If Italian in-line engines in the 1000-1500 hp class were not sent into production, it is also because that area was covered by the production licenses.

 

[gjs238]

B-29

Eventually it got what it needed, the Pratt Whitney R-4360 Wasp Major

 

[Civettone]

DW, I agree with you on all accounts. I just considered maintenance problematic as another form of unreliable.

The P.XII is interesting because it it was called a 'cold' engine, because of its very low RPM. 2,400 rpm IIRC. To me, it seems as an easy way to make an engine reliable, I guess any engine is reliable if you bring down the rpm enough.
Also, the Italian produced DB 605 did not have the same power output as the German one.
The Fiat A.80 or Piaggio P.XI were licence produced GR 14Ks, which was also produced by the Hungarians and Romanians. They all managed to make it more reliable than the Italian version.

Of course, the reasons is well known: autarky, which resulted in the use of inferior materials. I believe their engine designs were excellent, but they lacked the rare alloys to deal with the stress of high-performance engines. If they had these, the IF Zeta, Fiat A.82 or Piaggio P.XV would have brought their aircraft (Re.2004, Fiat G.57 and Piaggio P.119) up to the standards of the West. Or would have allowed them to produce more and better DB 601/605s.


Kris

 

[Dogwalker]

The P.XII is interesting because it it was called a 'cold' engine, because of its very low RPM. 2,400 rpm IIRC. To me, it seems as an easy way to make an engine reliable, I guess any engine is reliable if you bring down the rpm enough.

Whatever his RPM were, at the time the P.XII was introduced, there were not many radials in the world that could confront it performance wise. The BMW801 A,B and C had a smaller frontal surface, but were heavier and less powerful (there is a small window, around 4000m in which the P.XII is more powerful of the C3 fuelled "D" too), and not so reliable. The Hercules had about the same frontal surface, was slightly heavier, and less powerful until the arrival of the 100/130 octane gasoline fuelled versions. The Wright R.2600, has the same frontal surface, was heavier, more powerful at any height, but required 100/130 octane gasoline only.
One may say that's easy way to make an hi-power engine reliable, if you have 100 octane gasoline at handy. If you have not, you have to increase the displacement and, consequently, bring down the RPM. If you can also do this, keeping the weight low, you're skilled too.
To me the P.XII and his successor, the P:XV were great engines, counting that Italians cease to develop engines in September 1943.

They all managed to make it more reliable than the Italian version

According to who? Perhaps, as for the case of the A.80, it depends on which the terms of comparison were. Italians have made it reliable enough to evolve the basic design, and to homologate more powerful versions of it up to 1700 ps (and in September 1943 was to be approved the 1800ps P.XXII). Where Hungarian and Romanian arrived?

Also, the Italian produced DB 605 did not have the same power output as the German one.

The Ra.1050 had an omologation power (maximum continuous for the Ra.1050, climb and combat power for the DB-605) of 1250ps at 2600rpm at 5800m, exactly as a DB605A-1.

 

[Ivan1GFP]

Kawasaki Ki-61 needed a better engine than it ever got.
Neither the Ha-40 nor the Ha-140 ever were that good and the basic airframe and armament package were very good.

The Il-2 was also quite underpowered for all the weight it was lugging around.


Civettone,
The Italian copies of Daimler Benz engines were actually quite good though they never had enough of them or the better superchargers the Germans were using. It is arguable that they were better than the equivalent German engines at least for durability.

Shortround6,
What was wrong with all the Klimov engines in the Yakovlev fighters?

- Ivan.

 

[Civettone]

Whatever his RPM were, at the time the P.XII was introduced, there were not many radials in the world that could confront it performance wise.

And yet it was only used on the P.108. The Z.1018, Z.511, S.84, ... were all powered by it but they wanted it replaced by the AR.135 ASAP. That gave me the impression that the Italians were very unhappy about the P.XII.
As you said, there were some carburator problems with the P.XII on the P.108, which indicates to me that it still had some teething problems, at least in 1941.
Yet, I think you are right to point out that it had good performance for its day. And yet, by 1943 they were stuck with the same engine with no new airplanes.

One may say that's easy way to make an hi-power engine reliable, if you have 100 octane gasoline at handy. If you have not, you have to increase the displacement and, consequently, bring down the RPM. If you can also do this, keeping the weight low, you're skilled too.
To me the P.XII and his successor, the P:XV were great engines, counting that Italians cease to develop engines in September 1943.

I definitely agree with that.
But for the record, wouldn't you say the P.XXII was the successor of the P.XII. It was derived from the P.XII and was being tested by the end of 1943. I always considered the P.XV similar to the Gnome-Rhone 14R. The P.XI was a GR 14K. The GR 14N was nothing more than a modernized and improved GR 14K, which seems to be similar to what the P.XIX was. The GR 14R was an improved GR 14N with a two-step supercharger, much like the P.XV was.

And as to the Romanians and Hungarians. I know the Hungarians were very unhappy about the Piaggio engine and preferred to use their own licence produced GR 14K. And never heard the Romanian IAR.80 pilots complain about their GR.14K, what's more, they managed to develop it further on their own, eventually reaching a 1000 hp.

The Ra.1050 had an omologation power (maximum continuous for the Ra.1050, climb and combat power for the DB-605) of 1250ps at 2600rpm at 5800m, exactly as a DB605A-1.

I only know that the German tests of the Italian 5-series clearly indicates that the Italian engines gave 100 hp less than the German counterparts.

Kris

 

[Dogwalker]

And yet it was only used on the P.108.

Also the use of P.XI on a fighter in 1939 had raised concerns. The conception of the Regia Aeronautica was to use small engines on fighters, and large engines on bombers, and even the P.XI was considered a Bombers' engine. The 1000hp engine for fighters had to be the A.76.

but they wanted it replaced by the AR.135 ASAP.

The AR 135 had 100 hp more with less frontal surface. Certainly would have been a superior engine, if it had worked, but mostly, as it was presented in 1937, it was expected for a longer time.

And yet, by 1943 they were stuck with the same engine with no new airplanes.

I think that we all know the history of the delay in production of the Z.1018. They had been so long that, in 1943, already had been tested and ordered versions with the P.XV.

But for the record, wouldn't you say the P.XXII was the successor of the P.XII. It was derived from the P.XII and was being tested by the end of 1943. I always considered the P.XV similar to the Gnome-Rhone 14R.

The P.XV was a powered-up PXII mantaining the same displacement, similar to the P.XI-P.XIX evolution. The P.XXII had still 18 cilinders, but with a bigger displacemet (156X176, 60.6 l).

I know the Hungarians were very unhappy about the Piaggio engine and preferred to use their own licence produced GR 14K.

Hungarians bought 70 Re.2000 along with the license to build 200 more with their engine. The decision had nothing to do with the reliability of P.XI, of which, when they decided to build the aircraft under license, they could not know anything. Given that they were already producing under license their 14K, they preferred to use that one for the local built Heja, instead of having to import from Italy engines and spare parts for the entire life of the aircrafts. To buy 70 complete aircraft, while they completed production lines for Heja was just the way to have the aircraft in line before. To say that they used the Manfred Weiss WM K-14 because they were unhappy with the P.XI is like saying that Italians produced the Ra.1050 because they were unhappy with the DB.605 they used until that moment.

And never heard the Romanian IAR.80 pilots complain about their GR.14K, what's more, they managed to develop it further on their own, eventually reaching a 1000 hp.

That's what the P.XI had from the start. Have you ever heard a Romanian complain about it?

I only know that the German tests of the Italian 5-series clearly indicates that the Italian engines gave 100 hp less than the German counterparts.

For that matter, the same document clearly indicates 580 l of fuel for the G.55 instead of 560 l it had really; for all the three fighters it clearly indicates that they are not usable as fighter-bombers, when all three of the tested types had the 160kg wing racks, and the Re.2005 even the ventral one, ecc... ecc...
I would be very surprised to know that even only one of the fighter of the "5 series" tested by the Germans in december '42 and in february '43, was not equipped with an original German engine. In february '43 the production of Ra.1050 barely begun. All fighters of the 5 series up to that moment, and probably still for two or three months later, were equipped with German engines.
Actually, I do not really think that many Germans have had the opportunity even to see, let alone test, a Ra.1050 before September 8, 1943. The vast majority of the Ra.1050 engines were produced after that date, and used directly by the Germans. To know how powerful they were from a German document, if we do not trust the Italian ones, we better look for one of 1944.

 

[Shortround6]

forget power per unit of Displacement.

What was more important to both engine designers and air frame makers was power to weight.

A small displacement, high rpm (and highly stressed) engine of a certain weight may put out about the same power as a large displacement, low rpm, lightly stressed engine of the same weight. The small displacement engine may be easier to streamline.

It turns out that the high rpm engines seemed to tolerate increased stress due to higher cylinder pressures (more boost) with less modification that the low rpm engines could tolerate increased rpm.

The Hercules and the Piaggio P. XI used the same bore and stroke and had the the same capacity but the Hercules was about 250lbs heavier even in the early models. The Piaggio was about 500lbs lighter than an early/mid R-2600.

If you only have fuel of a certain grade then building a heavy engine to withstand high cylinder pressures makes no sense.

 

[Civettone]

Also the use of P.XI on a fighter in 1939 had raised concerns. The conception of the Regia Aeronautica was to use small engines on fighters, and large engines on bombers, and even the P.XI was considered a Bombers' engine. The 1000hp engine for fighters had to be the A.76.

What would you say about the A.82? I have seen a proposal for the Fiat G.57, a G.55 with the Fiat A.82. Would that have been a possible engine for a fighter aircraft??
I assume the A.82 was derived from the A.80 and not the A.76?

The P.XV was a powered-up PXII mantaining the same displacement, similar to the P.XI-P.XIX evolution. The P.XXII had still 18 cilinders, but with a bigger displacemet (156X176, 60.6 l).

That is very interesting, but you are very right. The P.XV was a 18 cyl, not a 14 cyl as I thought. But, I always thought the P.XV had an output of around 1,500 hp, equal to that of the P.XII. And wouldn't the P.XV still be too big for fighter aircraft?

Excellent points on the Hungarian and Rumanian engines. The original GR 14K had some trouble of its own. Especially oil leakages IIRC.

For that matter, the same document clearly indicates 580 l of fuel for the G.55 instead of 560 l it had really; for all the three fighters it clearly indicates that they are not usable as fighter-bombers, when all three of the tested types had the 160kg wing racks, and the Re.2005 even the ventral one, ecc... ecc...

The test reports clearly state that they did not consider the 5-series useful as Jabos because of the location of the oil cooler.

I would be very surprised to know that even only one of the fighter of the "5 series" tested by the Germans in december '42 and in february '43, was not equipped with an original German engine. In february '43 the production of Ra.1050 barely begun. All fighters of the 5 series up to that moment, and probably still for two or three months later, were equipped with German engines.
Actually, I do not really think that many Germans have had the opportunity even to see, let alone test, a Ra.1050 before September 8, 1943. The vast majority of the Ra.1050 engines were produced after that date, and used directly by the Germans. To know how powerful they were from a German document, if we do not trust the Italian ones, we better look for one of 1944.

Your suspicion may well be justified. But I think the Germans must have been meticulous in their testing, even if they got the fuel capacity a bit off. However, it may very well be that the very first Italian produced engines were used on these aircraft with the natural reduced power as a consequence. That would also indicate that the standard RA as produced in 1943 had the same power output as the DB 605. However, I have read that there were some small differences. From the Italian wiki: "I DB 605C prodotti dalla FIAT avevano un rapporto di riduzione tra albero motore e elica diverso da quello di serie: 1:0,485 e non 1:0,593." If correct, why was this?

That also brings me to another point. I said before that the main problem with Italian high-powered aircraft engines was the lack of metal alloys. You seem to steer more in the direction of a lack of high-grade fuel as the main limitation to achieve the necessary boost, like the Allies and Germans could use on their engines.

And thanks DW, this is very interesting stuff !
Kris