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Engine superchargers?


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shapeshifter #21 Posted Jan 22 2015 - 04:51

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I know the T1E2 prototypes engine had a compression ratio of 6.3:1 as did the T1E1 model.

 

Production model of the M6 had it lowered to 4.92:1 and in testing they complained it lowered the performance quite a bit as the gear ratio between the engine and the torque convertor was still set up as if it was 6.31:1 and wished it to be changed back to match the T1E1. (M6A2)



Blackhorse_Six_ #22 Posted Jan 22 2015 - 05:04

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Supercharger might make an interesting Equipment Module.

shapeshifter #23 Posted Jan 22 2015 - 05:43

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The G-200 used in the T1/M6 was a G9GC model engine and used 92 octane gasoline. Same engine used on some of the B-17s

 

If anyone still has the drawings and specs for the conversion it would probably be here.

http://www.libraries...files/ms356.pdf

 

An example

 

Manufacturer Wright
Name Cyclone 9
Model 704C9GC1
Horsepower 1200
No of cylinders 9
Super charger 7.14, 10.0
Comp. Ratio 6.07
Octane GR 91/96
Bore 6-1/8
Stroke 6-7/8
Max RPM 1 min 2500 (1200 hp)
Continuous RPM 2300 (1000 hp) or 2400 (1100 hp)
Weight 1320 Lbs


Edited by shapeshifter, Jan 22 2015 - 06:21.


Meplat #24 Posted Jan 22 2015 - 06:34

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View Postshapeshifter, on Jan 21 2015 - 21:43, said:

The G-200 used in the T1/M6 was a G9GC model engine and used 92 octane gasoline. Same engine used on some of the B-17s

 

If anyone still has the drawings and specs for the conversion it would probably be here.

http://www.libraries...files/ms356.pdf

 

An example

 

Manufacturer Wright
Name Cyclone 9
Model 704C9GC1
Horsepower 1200
No of cylinders 9
Super charger 7.14, 10.0
Comp. Ratio 6.07
Octane GR 91/96
Bore 6-1/8
Stroke 6-7/8
Max RPM 1 min 2500 (1200 hp)
Continuous RPM 2300 (1000 hp) or 2400 (1100 hp)
Weight 1320 Lbs

 

Not going to dig through my manuals, but the derating (probably via blower ratio and not compression ratio) probably stemmed from the U.S. mil standard fuel being 80 octane.

 

An aside-

The figures you're posting would not be very tank friendly as they are for a mill with two blower settings, which while fabulous for aircraft use would not be very useful in a ground vehicle.



Meplat #25 Posted Jan 22 2015 - 06:37

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View PostBlackhorse_Six, on Jan 21 2015 - 21:04, said:

Supercharger might make an interesting Equipment Module.

 

Maybe a MW50+ GM-1 setup for the German tanks, hahaha!

shapeshifter #26 Posted Jan 22 2015 - 06:40

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View PostMeplat, on Jan 22 2015 - 00:34, said:

 

Not going to dig through my manuals, but the derating (probably via blower ratio and not compression ratio) probably stemmed from the U.S. mil standard fuel being 80 octane.

 

An aside-

The figures you're posting would not be very tank friendly as they are for a mill with two blower settings, which while fabulous for aircraft use would not be very useful in a ground vehicle.

 

Odd they would keep the T1E1 versions using the higher rating then. Perhaps as they were only going to be used within the continental united states they figured they would have easier access to 92 octane rating and thus no need to lower to 80. the T1E2 and T1E3 were going to be lend lease versions shipped overseas.

Meplat #27 Posted Jan 22 2015 - 06:49

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View Postshapeshifter, on Jan 21 2015 - 22:40, said:

 

Odd they would keep the T1E1 versions using the higher rating then. Perhaps as they were only going to be used within the continental united states they figured they would have easier access to 92 octane rating and thus no need to lower to 80. the T1E2 and T1E3 were going to be lend lease versions shipped overseas.

 

The 92 octane stuff was an odd military only fuel that did not last much past the war.

They could run the mills that were rated for 92 on 100/130 or 115/145 with little trouble other than increased lead fouling on the plugs, but I'm doubting there were any plans to have a two speed blower in any of those applications.

Just no point in doing so.



shapeshifter #28 Posted Jan 22 2015 - 07:43

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Going over the report again and the First model of Carburetor used was a Chandler Evans  Model CECO 1900 PB something. This was then replaced with the one that "gave greatly improved performance" trying to find if they name that model.

Edited by shapeshifter, Jan 22 2015 - 07:44.


Meplat #29 Posted Jan 22 2015 - 07:53

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View Postshapeshifter, on Jan 21 2015 - 23:43, said:

Going over the report again and the First model of Carburetor used was a Chandler Evans  Model CECO 1900 PB something. This was then replaced with the one that "gave greatly improved performance" trying to find if they name that model.

 

Probably a Bendix pressure carb. They were a common replacement for the CECO.

shapeshifter #30 Posted Jan 22 2015 - 08:07

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found the model of the orig further in the document, CECO 1900 CPB-2

Meplat #31 Posted Jan 22 2015 - 08:10

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View Postshapeshifter, on Jan 22 2015 - 00:07, said:

found the model of the orig further in the document, CECO 1900 CPB-2

 

Must have been sticking all the Bendix carbs on things with wings. The CECO's worked, and did the same job as the Bendix but with what seemed like 3X the parts.

shapeshifter #32 Posted Jan 22 2015 - 08:12

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Found the supercharger ratio as well used in the tank 7.0:1 that was with the first model, no data given for the "improved" one

 

Impeller diameter of 11.00 in.

 

the new one I believe was still manufactured by Chandler Evans as at one point they had a representative from them come by and increase the air intake for the carb. they don't give a model or any specs just the "greatly improved performance" over the first model used.


Edited by shapeshifter, Jan 22 2015 - 08:19.


Meplat #33 Posted Jan 22 2015 - 08:22

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View Postshapeshifter, on Jan 22 2015 - 00:12, said:

Found the supercharger ratio as well used in the tank 7.0:1 that was with the first model, no data given for the "improved" one

 

Impeller diameter of 11.00 in.

 

 

7.0-1 is pretty common, and 11" is not unusual for a mill that big.

 

Basically the entire rear of the engine was part of the blower housing and accessory drive. That round part with all the black tubes coming off and running to the cylinders is the blower housing. The red bits are shipping plugs for the exhaust ports, and the beige bit is where the carb would have mounted.

 

 

 

 



shapeshifter #34 Posted Jan 22 2015 - 08:30

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Which all leads back to how did they rate the horsepower of the engine. Was the 960 hp using the base 6.31:1 ratio, or the new 4.35:1 ratio on production models, or was it taking into account the old supercharger with the 7.0:1 rating? And what would the "greatly improved" one have done for overall engine performance.



Meplat #35 Posted Jan 22 2015 - 08:47

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View Postshapeshifter, on Jan 22 2015 - 00:30, said:

Which all leads back to how did they rate the horsepower of the engine. Was the 960 hp using the base 6.31:1 ratio, or the new 4.35:1 ratio on production models, or was it taking into account the old supercharger with the 7.0:1 rating? And what would the "greatly improved" one have done for overall engine performance.

 

It's always BHP, off the spline (or flange in this case).

 

You're looking for tabular model data though-
The surest way is to get one of the old Wright product listings and look it up.

 

But just guessing at the application, they weren't going to drop a 1200HP mill in there, probably would be a single speed blower, running between 900 and 1000 HP, probably with a carb modified for automatic mixture control.

 

So a change of 50HP~100HP is not going to make much of a change in performance overall. They were probably changing engines to find one that worked with whatever experimental transmission was in the vehicle at the time.  The vehicle in question was never really a "production model", as most of that line ended up being tasked to be test mules for various drivelines, powerplants and armaments, when they weren't smashing cars for newsreels.

 



shapeshifter #36 Posted Jan 22 2015 - 08:54

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Twin disc Torque convertor was the transmission used in the pilot, and all production models (M6, M6A1) sans the T1E1 which had the engine directly connected to a pair of GE electric motors to drive the tank.

 

The only other transmission that was tested was a twin GM 3700 torqumatic one.

 

a 100 hp boost would still help, going from a 16.72 hp/t rating to 18.46 hp/t

 

And the engine was always the G-200 G9GC for all models built.

They originally wanted a 1000 hp engine from another manufacturer  but production was to tied up for aircraft for them to get any. (Id have to dig in my notes to find the make)

They were also going to test one with four GM 6-71 engines but canceled that in the end.

 

 


Edited by shapeshifter, Jan 22 2015 - 09:01.


Meplat #37 Posted Jan 22 2015 - 09:06

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View Postshapeshifter, on Jan 22 2015 - 00:54, said:

Twin disc Torque convertor was the transmission used in the pilot, and all production models (M6, M6A1) sans the T1E1 which had the engine directly connected to a pair of GE electric motors to drive the tank.

 

The only other transmission that was tested was a twin GM 3700 torqumatic one.

 

a 100 hp boost would still help, going from a 16.72 hp/t rating to 18.46 hp/t

 

 

 

Moot point, the thing was destined to be a CONUS testbed by it's size and design.

They could have stuck all kinds of crazy powerplants in there, and it would not have radically changed the vehicle's fate.
 



shapeshifter #38 Posted Jan 22 2015 - 09:24

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It was a production model, they standardized it hence the M designation for the M6 and M6A1. the reason it was never in combat was AGF only wanted M4's they didn't want to ship such a heavy vehicle when they could ship almost two M4's for the same weight.

 

Both British and American officers wanted it badly, and had been asking for it since the start of the Africa phase of the war. all the way up to 1944 they were still wondering and asking when they would get them. Even the Germans thought they would see them at any time and had a standing order to bring any examples found in the field back for study.

 

But all of that is moving away from the original topic.



stalkervision #39 Posted Jan 22 2015 - 11:33

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View PostBlackhorse_Six, on Jan 21 2015 - 23:04, said:

Supercharger might make an interesting Equipment Module.

 

agreed

SgtNuker #40 Posted Jan 22 2015 - 14:24

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View PostIOC_Cartmen, on Jan 20 2015 - 21:49, said:

Due to how a supercharger works, it's generally not a good choice for a diesel engine, and most tanks have diesel engines. Even still, I don't think many tanks have turbos either.

 

One such tank that has a diesel and is supercharged is the Ke-Ho. Granted, there are two things to note from this:

 

1). Ke-Ho ws a concept so proposed propulsion isn't really a factor.

2). Diesel engines of the day weren't really "Diesel", but more of kerosene burners. 

 

Another thing to note is that if a tank today has a diesel engine, they will have a turbo. In fact, a turbo is pretty much standard on a diesel engine because above 2000 rpm, the power a diesel generates drops drastically. Forced induction boliters that output to last through the rev range. 

 

View Postshapeshifter, on Jan 20 2015 - 21:51, said:

Some Shermans had Radial engines and the M6's used a Wright Radial as well. (aircraft engines)

 

Doesn't mean they couldn't utilize forced induction. The Sherman may not have, but aircraft with radial engines did use forced induction to cope with the high altitudes. 






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