Advantages & Disadvantages: Nations & Doctrine, Aircraft and Technology of WWII (1 Viewer)

Zipper730 · Feb 1, 2017

Shortround6 said:

It looks like a variety of things could be moved around, though I don't know how much they weigh. Do you have a diagram of a P-36 or a P-40 for comparison?

Table of turbo characteristics: http://www.enginehistory.org/Turbochargers/GETurbochargerData.jpg

What version was used on the YP-37?

I got a lot of questions for the rest

What's a scroll & torus type nozzle box: What advantages & disadvantages they got?
What's an upstream exhaust? I figure you'd want the exhaust downstream of the turbo...
What's the advantages of an angled exhaust, a straight exahust, and an angled & straight exhaust pathway?
What disadvantages do a cooling shroud produce?

Now for comparisons sake, the intercooler and ducting on the B-24, a 1200hp engine,

Large rectangular finned box on the right is the intercooler. Copper unit is the oil cooler. The XP-37 needs a coolant radiator to boot.

So the oil cooler could be enlarged to be a radiator and oil-cooler in one, and the inter-cooler could have been mounted into the wings, and the turbo could be mounted further behind the engine?

Sticking turbo systems in skinny single engine fighters was not easy.[/QUOTE]True, but wouldn't

Shortround6 · Feb 1, 2017

Zipper730 said:
It looks like a variety of things could be moved around, though I don't know how much they weigh. Do you have a diagram of a P-36 or a P-40 for comparison?

What version was used on the YP-37?

I believe it was the B1.

I got a lot of questions for the rest

What's a scroll & torus type nozzle box: What advantages & disadvantages they got?

What's an upstream exhaust? I figure you'd want the exhaust downstream of the turbo...

What's the advantages of an angled exhaust, a straight exahust, and an angled & straight exhaust pathway?

What disadvantages do a cooling shroud produce?

Upstream would be like a P-47

two doors on the lower fuselage are the outlet/s to the oil cooler (one on each side) the pipe right behind it is the wastegate outlet, again one on each side. This may save on linkages running back and forth through the fuselage. It doesn't really matter where the waste gate is if you can get enough exhaust gas to the turbo with the waste gate closed or get the exhaust to dump out when you want.

Video of P-47 starting.

Please note that if there was a problem starting you could fill the whole exhaust system with flammable vapor and if it lit off then you could blow the system apart. A lot of the differences were not real improvements, they just suited the units to different installations. P-38s ran their turbos upside down compared to B-17s and B-24s for instance. Early (pre war and early war) turbo controllers gave a lot of trouble, later ones were much better and eliminated and lot of problems.

So the oil cooler could be enlarged to be a radiator and oil-cooler in one, and the inter-cooler could have been mounted into the wings, and the turbo could be mounted further behind the engine?

A radiator would be roughly two to three times the size of the oil cooler. Oil systems and cooling liquid operated at different temperatures and generally required different ducts/doors/flaps to get optimum conditions for each.

Zipper730 · Feb 14, 2017

nuuumannn said:
The first Russian jet engine was designed in 1937 by A.M. Lyulka, although he didn't begin working on hardware until around late 1939, 1940, as the RD-1, with around combustion chamber and turbine section undergoing testing a year later.

I've never seen this design...

The German invasion put paid to further development until 1944. Independent of anyone else's research, Lyulka proposed high bypass engine for which he received certification from Moscow, and afterburners.

Advanced...

But to say that other nations didn't is not true.

No, but we seemed to consistently pursue it

Shortround6 said:
I believe it was the B1.

Okay

Upstream would be like a P-47

Would this conserve length?

Please note that if there was a problem starting you could fill the whole exhaust system with flammable vapor and if it lit off then you could blow the system apart.

Was this a problem more prone to certain a/c?

A radiator would be roughly two to three times the size of the oil cooler.

I'm just basing this on the P-40 and P-51 which had the oil-cooler and radiator in the same duct.

Shortround6 · Feb 15, 2017

Zipper730 said:
Would this conserve length?

Not really

waste gate is the short pipe to the rear of the turbo. It would work if placed in the pipe leading to the turbo and savings in length is minimal. It may introduce other problems. You do want the exhaust directed away from the aircraft to some extent.

Old Wizard · Feb 15, 2017

Zipper730 · Feb 15, 2017

Wuzak

There doesn't seem to be much room for a radiator under the spinner unless the turbocharger was moved rearwards. It seems like you would require the scoop to provide engine radiator, oil-cooler, and inter-cooler functions. This is similar to the P-40 except the inter-cooler part.

The other possibility would be to have the engine radiator, oil-cooler under the spinner, with the inter-cooler intake in a different location.

Shortround6 said:
Not really

Okay

It may introduce other problems.

Such as?

You do want the exhaust directed away from the aircraft to some extent.

Makes sense

wuzak · Feb 16, 2017

Zipper730 said:
There doesn't seem to be much room for a radiator under the spinner unless the turbocharger was moved rearwards. It seems like you would require the scoop to provide engine radiator, oil-cooler, and inter-cooler functions. This is similar to the P-40 except the inter-cooler part.

You understand that this:

Shortround6 said:
Not really

Is the picture of a B-17 installation, one with a single row radial engine and a ring collector exhaust pipe?

With the V-1710 the exhaust would be routed from further back than is shown here.

You can also see that the exhaust comes out behind the cooling flaps, and the engine in the background shows the depth ahead of the flaps, which should allow space for a radiator.

wuzak · Feb 16, 2017

The Boeing XB-38 had the turbo in the same place as the B-17 and had the intercooler under the spinner.

Both from Atomic Toaster: The Boeing XB-38 Watercooled Fortress

Note the exhaust pipe is visible on the inner nacelle because the wheel well is in the way for routing as in the outer nacelles (same situation exists in B-17).

The turbos on the XB-38 were in the same location as the B-17.

The radiators were placed in the leading edge, between the nacelles. I wonder if these could have been placed up front too - certainly it could with an annular radiator.

Or they (Curtiss) could relocate the radiators to the leading edge.

wuzak · Feb 16, 2017

Zipper730 said:
What version was used on the YP-37?

Shortround6 said:
I believe it was the B1.

It was actually the B-2.

The XP-37 (Curtiss 75I) used the Form 10 turbocharger, whiuch had the compressor reversed from later practice and drew the induction air over the centre Bearings. Later this was changed to the Form 13 turbocharger, which would be redesignated B-1. It seems that the Form 13/B-1 was installed when the aircraft was upgraded to Curtiss Model 80 standard.

The YP-37 (Model 81) was to have the B-1, but the improved B-2 had become available, and that was used instead.

Zipper730 · Feb 16, 2017

wuzak said:
You understand that this:

Is the picture of a B-17 installation, one with a single row radial engine and a ring collector exhaust pipe?

With the V-1710 the exhaust would be routed from further back than is shown here.

I assume the forward fuselage would still be a little longer than the P-40, just not as long?

wuzak · Feb 16, 2017

Zipper730 said:
I assume the forward fuselage would still be a little longer than the P-40, just not as long?

I shouldn't think it would be any longer than a P-40, if you had the intercooler under the nose and the radiators in the leading edge of the wings.

Zipper730 · Feb 17, 2017

Uh, there's no need for this

Zipper730 · Mar 8, 2017

wuzak said:
I shouldn't think it would be any longer than a P-40, if you had the intercooler under the nose and the radiators in the leading edge of the wings.

So basically the goal would be to move the turbo under the wing-center and then put the radiator under the spinner much like the P-40 was configured with the oil-coolers, radiator and either the intercooler airflow under the spinner, or put the intercooler flow in the wing root?

The radiators on the sides of the plane would now be under the nose and could avoid producing so much excess length, and the cockpit could be moved forward and the tail lengthened to a design of better proportions.

Also, can I forward this to a person I know on another forum?

Zipper730 · May 16, 2017

nuuumannn said:
The first Russian jet engine was designed in 1937 by A.M. Lyulka, although he didn't begin working on hardware until around late 1939, 1940, as the RD-1, with around combustion chamber and turbine section undergoing testing a year later.

That the one with the monster combustion chamber?

The German invasion put paid to further development until 1944. Independent of anyone else's research, Lyulka proposed high bypass engine for which he received certification from Moscow, and afterburners.

I would have never known that...

This link to Wiki mentions a couple of entries on altitude records

I was trying to point out that the USAAF seemed to develop most consistently aircraft with high-altitude capability from the outset: The British and Germans did build some high altitude designs, but they didn't seem to pursue the idea as determinedly for operational line-aircraft as the US did.

I'm fascinated that there was a flight over Mt. Everest with a biplane, but this didn't seem to be an example of a line aircraft: It was a specialized aircraft for setting a record, it would seem. The Bristol 138 was the same, a research aircraft, not a production line aircraft.

I'm not sure if I'm not articulating myself right, the turbochargers were a big thing, but they weren't the only thing however in terms of high altitude. This variable only applies early on though, by the end of the war the USAAF and RAF both had high altitude aircraft, the Luftwaffe had jet-fighters which also could work well at high altitudes, as well as jet-bombers in service.

Yet, the most common US fighters at the time WW2 kicked off, 1939 not 1941, were easily outperformed at altitude by their European contemporaries. The P-40 and P-39 were no match for the Bf 109 and Supermarine Spitfire at height in 1939/1940.

So, I suppose one advantage the US had was that we weren't in the war first and were able to learn from the mistakes of others ?

Shortround6 said:
3. P-40...............6787lbs or more The P-40Bs and Cs actually went 7350-7500lbs even with less than full fuel tanks.

Yikes that was heavy... what caused all that weight-gain?

Zipper730 · May 16, 2017

This one goes to the RAF: It seems of all the air-arms, they made the decision of picking the biggest, most cavernous bomb-bays. One advantage the RAF had was not just the ability to carry heavy ordinance loads, but the ability to carry large ordinance as well.

The Luftwaffe could carry some interesting weapons, such as modified sea-mines for use as b-busters; the RAF however could carry them inside the bomb-bays. The Wellington, Halifax, Stirling, Manchester, and Lancaster all had quite wide bomb-bays; the Manchester and Lancaster might have had the longest.

It definitely makes clear one point: If given the choice between two small bomb-bays, or one huge one -- pick the huge one if you can!

wuzak · May 16, 2017

Zipper730 said:
This one goes to the RAF: It seems of all the air-arms, they made the decision of picking the biggest, most cavernous bomb-bays. One advantage the RAF had was not just the ability to carry heavy ordinance loads, but the ability to carry large ordinance as well.

The Luftwaffe could carry some interesting weapons, such as modified sea-mines for use as b-busters; the RAF however could carry them inside the bomb-bays. The Wellington, Halifax, Stirling, Manchester, and Lancaster all had quite wide bomb-bays; the Manchester and Lancaster might have had the longest.

It definitely makes clear one point: If given the choice between two small bomb-bays, or one huge one -- pick the huge one if you can!

The size and weight of bombs that could be carried in each bomb bay was different.

The Wellington, for example, had two racks creating 3 bays in its bomb bay.

The racks could, and were, removed to carry the 4,000lb HC "Cookie".

I believe the Stirling's bomb bay restricted the diameter and length of ordnance that could be acrried.

I believe those are the 2,000lb HC bombs being loaded into the Stirling. I don't believe the Stirling could carry the 4,000lb HC bomb.

Ascent · May 16, 2017

I believe the size of the bomb bay on the Manchester, and thus the Lancaster, was to allow it to fit a torpedo.
Seems a little ironic that it had such a useful space for ordinance because it was designed for a weapon it never used.

wuzak · May 16, 2017

Ascent said:
I believe the size of the bomb bay on the Manchester, and thus the Lancaster, was to allow it to fit a torpedo.
Seems a little ironic that it had such a useful space for ordinance because it was designed for a weapon it never used.

Yes, the Manchester was designed to take two torpedoes, and these were to be carried end to end, hence the length of the bomb bay.

Shortround6 · May 16, 2017

Not sure what the advantage of carrying the torpedoes end to end would be in a bomb bay that was 5 feet wide.

you had 33 ft of length and a MK XII torpedo was 16ft 3 in long which sounds like a tight fit. Perhaps the slightly older MK XI was shorter?

wuzak · May 16, 2017

Shortround6 said:
Not sure what the advantage of carrying the torpedoes end to end would be in a bomb bay that was 5 feet wide.

you had 33 ft of length and a MK XII torpedo was 16ft 3 in long which sounds like a tight fit. Perhaps the slightly older MK XI was shorter?

Look at it this way - if the torpedoes were carried side by side, why did they need a bomb bay 33ft long?

Advantages & Disadvantages: Nations & Doctrine, Aircraft and Technology of WWII (1 Viewer)

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