Allison V-1710 Supercharger Impeller

[Elvis]

Wouldn't that simply be a fact of those lists.
They match engines that were actually used in service....so maybe the even numbered Allisons were experiementals and thus, don't relate?

....JMHO

Something else this thread reminded me of.
Have you seen this before? - Allison V1710 Engine
Relates more to usage in Unlimited Hydroplanes, but some good info on the history of the engine.
Might not neccessarily help you, in regards to this particular thread, but it emlightened me to some facts about its history that I was unaware of prior.



Elvis

 

[kool kitty89]

That wouldn't explain the listed radial engines though.

 

[peril]

I think you may find clockwise rotation engine is odd number and anticlockwise even numbered

 

[kool kitty89]

No, at least not for the V-1710 (not sure about the radials)

The V-1710-29 was the F2L model, the -53 was the F6L, the -55 was the F10L, the -77 was the F15L, the -91 was the F17L, and the -113 was the F30L. (all are also P-38 engines)

 

[jerryw]

Production of aero-engines for US armed services required that engines for the ARMY had ODD dash numbers and engines for the NAVY had EVEN dash numbers.

 

[kool kitty89]

Thank you. (that would explain it) There doen't seem to be a similar Navy engine article, but there's a lot more info here: Reference

 

[hrandy]

Actually Red Admiral, Dan Whitney in his superb book Vee's for Victory is right and you are wrong. You are wrong in your interpretation of the Model Designations of U.S.A.F. Aircraft Engines table and wrong in discrediting a book you have obviously not ever even opened.

The -45, -93, -109 and -101 Allisons are two stage engines with a single speed gears driving the main stage and another set of single speed gears driving a variable speed hydraulic clutch for the auxiliary stage.

the -111 uses a single speed mechanical supercharger along with a GE turbocharger in the P-39.

The one and only experimental -57 used a two speed single stage "mixed flow" "Birmann" (named for the designer) supercharger from the Turbo Engineering Company of New Jersey. Like the experimental Birmann turbochargers TEC produced in very small numbers for the U.S. Navy during the Second World War performance was about equivalent to designs already in mass production.

The -97 was a late war experimental single speed single engine with a 10.25 inch diameter supercharger. Either 7.48:1 or 9.60:1 supercharger gears were used depending on the altitude performance required. Only three or four were produced.

The -131 was a true two speed single stage engine produced in very small numbers (less than ten engines total) for the stillborn Douglas XC-114 and YC-116 in 1946. The Allison designation was V-1710-G-3R not V-1710-C3 as stated in the U.S.A.F. Aircraft Engines table.

Dan Whitney documents several other experimental single stage two speed 1710s in Vee's for Victory. Altogether of the more than 69,000 1710s that were produced by Allison less than thirty had single stage two speed mechanical superchargers.

Before reading Vee's for Victory I considered the Allison 1710 a second rate engine compared to the Roll-Royce Merlin. Rolls-Royce received millions from the British goverment to develop the Merlin while Allison received hollow promises from the USAAF. That's the real reason the Merlin became a better engine than the 1710.

Red Admiral if you ever make the effort to read Vee's for Victory you will be enlightened.

 

[red admiral]

Actually Red Admiral, Dan Whitney in his superb book Vee's for Victory is right and you are wrong. You are wrong in your interpretation of the Model Designations of U.S.A.F. Aircraft Engines table and wrong in discrediting a book you have obviously not ever even opened.

One official primary source says one thing, a secondary source says another. From what you've said the primary source isn't clear and the two gear ratios listed are for both parts of the unit. However for other two speed engines the notation is exactly the same. I was hardly discrediting the book, just that the available information said differently. I've heard good reviews of Whitney's book, and if I ever see a copy at a reasonable price I'd probably get it.

 

[hrandy]

Red Admiral first let me apologize for the tone of my previous post. I got a little excited when I saw your comment that Dan Whitney was wrong. Vee's for Victory is simply a fantastic book from a very talented author. Dan Whitney did an incredible amount of research and in my opinion deserves to be recognized as the authority on the Allison 1710.

This isn't a case of a primary source and a secondary source saying two different things. What you call the primary official source, Model Designations of U.S.A.F. Aircraft Engines and what you call the secondary source, Dan Whitneys' Vee's for Victory, are in agreement except for one copy error and one typo in the Model Designations of U.S.A.F. Aircraft table. You simply have misinterpreted what the information in the Model Designations of U.S.A.F. Aircraft Engines table means.

For example in the -45 row the Aircraft Engines table notes in the Description column that the -45 has an auxiliary second stage supercharger and in the Supch (Supercharger) column lists Geared, 9.5, 8.1:1, 6.85:1. Somehow you interpret that information to mean a single stage two speed supercharger. Vee's for Victory has much more information on the -45 which has a 9.5 inch primary stage supercharger driven by a 8.1:1 ratio gear set and an auxiliary supercharger driven by a 6.85:1 gear set driving a hydraulic variable speed clutch.

If you understand the information in the Model Designations of U.S.A.F. Aircraft Engines table it is obvious that the -45 is not a single stage two speed engine.

Similarly the -93, -101 and 109 are two stage engines which, if you had the luxury of being able to refer to Vee's for Victory you would know, have some minor variations to the basic two stage primary and auxiliary supercharger equipped -45.

The -111 is a turbocharged engine used in Lockheed Lightning variants. I believe the Geared, 9.5, 8.1:1, 7.23:1 information in the Supch column is simply a copy error from the -109 and 109A information.

The -57, -97 and -131 are indeed single stage two speed engines. Both sources agree on the details except for the typo in the Aircraft Engines table that designates the -131 as a V-1710- C3. The -C3 was a very early engine with the military designation V-1710-5 (XV).

Your original post gives the impression that there were significant numbers of single stage two speed 1710s. On careful examination of the eight variants listed by you as single stage two speed engines only three can be classed in that category. The production of those three variants was less than two dozen total. So I think that I can say with certainty that single stage two speed 1710s were a minor footnote in the complex history of this interesting engine.

 

[red admiral]

For example in the -45 row the Aircraft Engines table notes in the Description column that the -45 has an auxiliary second stage supercharger and in the Supch (Supercharger) column lists Geared, 9.5, 8.1:1, 6.85:1. Somehow you interpret that information to mean a single stage two speed supercharger.

The list isn't consistant with itself. To me, that means a 9.5" diameter impeller with two gear ratios. If we look at the V-1650-1 which is a single stage two speed engine, its listed as 10.25", 8.150:1, 9.490:1 in the same manner as for the V-1710-45 but meaning something else. For two stage engines it usually gives both impeller diameters. Its only with more information its possible to see differently.

Is there any mention of post-war use of V-1710s for hydroplane racing in Whitney's book? I occasionally hear claims of 4000hp+ which seem doubtful.

 

[hrandy]

I would agree the the Aircraft Engines table tries to do too much in too little space leaving a too much open to interpretation.

Vee's for Victory does have a chapter on post war air water and drag racing. Dan Whitney speculates horespower ratings in the low three thousand range. Four thousand horsepower does sound hyperbolic to me.

 

[Elvis]

I grew up and still live near the Seattle area and I'm a big Hydro fan going back to the late 60's, during the heyday of the Miss Bardahl (the yellow and black checkered boat, not the earlier green one).
Most of those claims, during the "piston" era were in the 2000-3000 HP range and the reason they got such high numbers is because they spun those engines a lot faster than the USAAF or anyone else ever did.
It was the later Griffon's that pushed the HP up into the 4K-5K territory.
Racers live on the "ragged edge" and push their equipment to the limit.
There was also use NoX (see the movie "Madison") and multiple turbo-supercharging systems developed specifically for pushing those boats as fast as they possibly could on those courses.
Google a Hydroplane from the 1970's called "Miss US" and you'll see all kinds of info on the V-1710 (or look back a page or two in this thread. I provided a link in one of my earlier posts).



Elvis

 

[siznaudin]

Did any of these hot rodded aero engines go on a dyno to give a semblance of credibility for their stratospheric power claims? Just asking ....

 

[Elvis]

Yes, they did.
Can I produce proof that they did? No, I can't, but if I ever do, I'll let cha' know.


Elvis

 

[Vintageaeroengines]

Interesting thread
Having 40+ years experience in overhauling these engines I would note some things.
The C, E, F etc were Allison numbers.
The -numbers were Army air specs.
The dash numbers were in blocks based on the mod state and HP increase.
The P 39 did not have a turbo.
The P 63 had the aux supercharger so was a two stage set up.
The impeller on most of the engines is the 9.5".
However most people never notice the angle difference between the different gear ratios and turbocharged engines.
The slower gears had a 4 degree different angle on the leading edge of the blades.
Swapping the impeller/gears on a P38 engine for the Reno races made a big difference in top speed for Lefty's racer.
The Merlin engine is a whole different story.
The development of Strega's engine and its history is worth its own thread.
Mike

 

[MiTasol]

Dan Whitney's Vees for Victory is incorrect in this regards. Theres a nice list published by Air Material Command which gives the model designations of USAF engines including details on usage, powers, displacement, supercharger details, prop details etc.

Single stage and two speed versions were; -45 -57 -93 -97
-101 -109 -111 -131

Dan Whitney's book is absolutely correct and the USAF report is incorrect in a number of sections as well as being misinterpreted in others due to a fundamental misunderstanding of the way the Allison engines were constructed and described. See the two pictures below or better still read Whitney's book as it describes the various models and the ASB variants in detail

Examples proving Whitney's book correct are:

1. Regarding misinterpretation, your reference clearly shows that the -45 and all other engines derived from (-57, etc) it have the Auxiliary Stage Boost/Blower/Supercharger listed in the Description column. That is an EXTERNAL supercharger, shaft driven via a clutch, not an integral supercharger - see the pictures below for a quick visual or read Whitney's book for detail. The "second SPEED" shown is actually a second STAGE, but in many installations the ASB supplies pressurized air to the carburettor, similar to a turbosupercharger whereas a second speed supercharger has just one impellor and a gear change mechanism to change the speeds. These engines you list are all single stage engines with an external second stage added. They show two supercharger impellers and two gearings but only one is integral with the engine and that is not two speed.
   
2. Attached are pages from Tech Order 02-5AB-2 which covers the -111, one of the engines in your list, along with the -113 on the USAF list as two speed. The file covers the Title page (identifies models), page 5/6 which cover model differences and specifically states "The engines covered in this handbook are basically similar in appearance and design" and "with built in single speed, single stage supercharger" and page shows the supercharger drive gearing which again shows single speed, pages 26/28 with the engine specifications, again showing single speed only. Given this manual was written when the engines were in service and actually being worked on it is a far more trustworthy document than a table written long after these models were retired.
3. pages from the -89/91 and -111/113 parts catalogs showing the gear drive to the supercharger are also attached.

Unfortunately I do not have any of manuals for the ASB engines

 

[MiTasol]

Another thing to note is that nearly all the models listed are odd numbered, virtually no even numbered models are listed.

Under the protocols of the day all Army engines had odd dash numbers and all Navy engines had even numbers. The Navy used very few Allisons, mainly in airships

 

[MiTasol]

I think you may find clockwise rotation engine is odd number and anticlockwise even numbered

R and L indicate the direction of rotation, R being clockwise when viewed from behind.

F5R, F5L V-1710-49, -53 P-38F engine

F10R, F10L V-1710-51, -55 P-38G engine

F15R, F15L V-1710-75, -77 XP-38K engine

F-17R, F17L V-1710-89, -91 P-38H & J

F30R, F30L V-1710-111, -113 P-38L engine

 

[Elvis]

Under the protocols of the day all Army engines had odd dash numbers and all Navy engines had even numbers. The Navy used very few Allisons, mainly in airships

That's a good thing, since the Allison was originally designed to power airships! =)

 

[Shortround6]

Not sure they were ever used in airships. Airships may have crashed/ been withdrawn from service before Allison delivered any production airship engines.
Test flights aside? One engine out of eight was an Allison?