Allison v-1710 Engine Life

[MakerDude]

I have been researching Soviet P-39 and P-40's. One curious thing I came across is they had much shorter engine life.
"It is true that because of our unforeseen operating regime the engines had a limit of about 50 hours, and often less. Normally an engine might last 35 hours and then it was replaced."

Anyone know how long the Allison lasted in American flown planes?

Source

Conversations with N.Golodnikov. Part Four – Lend-Lease

From various sources it seems the Soviets were not using as good fuel, going higher rpm, and had lower quality oil.

 

[Deleted member 68059]

I have been researching Soviet P-39 and P-40's. One curious thing I came across is they had much shorter engine life.
"It is true that because of our unforeseen operating regime the engines had a limit of about 50 hours, and often less. Normally an engine might last 35 hours and then it was replaced."

Anyone know how long the Allison lasted in American flown planes?

Source

Conversations with N.Golodnikov. Part Four – Lend-Lease

From various sources it seems the Soviets were not using as good fuel, going higher rpm, and had lower quality oil.

The problem in Russia was usually the incredibly abrasive dust that the quick-build airfields churned up. Exactly the same happened to Hurricanes operated there, the cylinders were worn out after a tiny time interval, and the service personnel there got used to quick fix procedures like replating bores because they`d never get new liners as spare parts in time.

Conditions there were judged to be not that dissimilar to operating in the desert, with regards to vastly shortened engine life.

 

[special ed]

One of my books by a Russian author said Russian pilots flew at full throttle rather than cruise settings. I have wondered about engine life.

 

[MakerDude]

One of my books by a Russian author said Russian pilots flew at full throttle rather than cruise settings. I have wondered about engine life.

Ya that's what I read in various sources. They must have been asking for a lot of replacement Allisons.

 

[ThomasP]

I was told that when the Russian sources are interpreted as 'full throttle' it means full rated power or what the US usually labeled Normal power.

 

[Shortround6]

I was told that when the Russian sources are interpreted as 'full throttle' it means full rated power or what the US usually labeled Normal power.

If that is true, and I am not saying that it is not, it does help explain a few thing though.
The Allison were rated at 1000hp at 2600rpm at around 38-39in. Might depend on exact model, carb, backfire screen and manifold.
Flying around at closer to 3000rpm and higher boost is going to suck up more fuel at a minimum, up to 20 gallons an hour more.
Ability to keep the engine cool might be problem depending on weather. The planes were supposed to run at 2600rpm limit for just about as long as the fuel was available.
Above 2600rpm is where the normal 5 or 15 minute time limit came in. Russians can do kind of what they wanted but when the temperature or oil gauges go into the red it is not just an American or Russian rule. The engine is going to stop running soon.

IN the US in training squadrons by 1944 they were getting 750hrs out of the Allisons.

 

[Deleted member 68059]

One of my books by a Russian author said Russian pilots flew at full throttle rather than cruise settings. I have wondered about engine life.

That seems a very strange claim, fuel consumption would be vastly higher, how did they fly anywhere ?

All pilots abused the boost settings when they were in combat, this happened all the time in the Battle of Britain for example,
but I cant believe Russian pilots just stuck everything on full after take off and flew around all day like that, why would you,
you`d know you are decreasing your chances of coming home if the engine packs in.

 

[Shortround6]

I am wondering if the habit of running at "normal" power had anything to do with the short engine life?
That is about the limit for "auto rich" and I am wondering if the rich mixture may have affected the oil on the cylinder walls and increased wear?
Auto-lean doesn't kick in until much lower, like under 750hp.

 

[BiffF15]

That seems a very strange claim, fuel consumption would be vastly higher, how did they fly anywhere ?

All pilots abused the boost settings when they were in combat, this happened all the time in the Battle of Britain for example,
but I cant believe Russian pilots just stuck everything on full after take off and flew around all day like that, why would you,
you`d know you are decreasing your chances of coming home if the engine packs in.

I have read something similar about the Russian pilots and high power settings. My interpretation is that they operated at high power settings (high speed) in the high threat areas (places they thought they could be attacked) to make any attempted intercepts more difficult. If you are at high or top speed, and your opponent is trying to intercept you, he either needs to be a good bit faster and or run the perfect pursuit curve if he intends to shoot you down. You give him the the smallest window of intercept possible by going as fast as you can.

Realize that this is but one way to tackle the problem. With better training you fly better formation, have a better visual lookout contract (who looks where and when), better tactics to handle interlopers, and better outcomes. Poor training you just haul arse…

The problem I think I see is either the pilot didn't explain it well (and I've seen pilots try to explain things to maintenance and totally get it wrong and we all have a common background of owning / operating vehicles) or the writer didn't get or convey what happened while putting it in print. We all have filters or biases that the next guy might not. Add to that 70 years of societal change with people like us are trying to figure out what really happened and what you have left is the group sharing of knowledge on sites like this.

Cheers,
Biff

 

[Geoffrey Sinclair]

Some of the 15th Air Force 1945 monthly reports have Engine Change Reports, graphs of average running time per aircraft engine changed. Generally speaking the R-1830 radials in the B-24 and the R-1820 radials in the B-17 had at least an average of 300 hours running when changed, few had 400, with the R-1820 ahead, most having 350 or more hours. Overhauled engines usually had around half the average hours of new engines. The V-1650 Merlins and the V-1710 Allisons usually averaged over 200 hours, few made it to 300 until March/April. Overhauled Allisons were around half the new engine hours, overhauled Merlins more like a quarter.

 

[ThomasP]

I am not that familiar with the air combat situation on the Eastern front. I am wondering how often the Soviet pilots took off using TO power, cut back to Climb (usually Normal power on US engines?), and:

were under threat/attack before they took off - ie the airfield was the combat area - so never got out of Normal or Military until it was over
ended up being engaged in combat before reaching their intended cruise/loiter altitude - so never got out of Normal or Military until it was over
reached the combat area before reaching their intended cruise/loiter altitude - and remained in Normal power for 'Combat cruise'

My understanding (may be wrong) is that until late-1944, most(?) of the air-air combat took place within 50-100 miles of the Soviet airbases, and since most of the Soviet air bases were within 50-70 miles (may be wrong) of the front lines . . . ? In some ways a situation similar to what the RAF faced in the BoB, at least as far as TO and Climb power to intercept altitude and then often immediately engaging in combat.

Maybe?

 

[Buz101]

Ya that's what I read in various sources. They must have been asking for a lot of replacement Allisons.

Interestingly the 200 odd Tomahawks the British sent them only came with 20 spare engines.... however later shipments came with about 25% plus spares (US found that 10% wasn't anywhere near enough - even though they were told early that it wasn't)). MakerDue can you drop me a PM with what you are actually researching I may have some data for you

Buz

 

[ddwhitney]

Interestingly the 200 odd Tomahawks the British sent them only came with 20 spare engines.... however later shipments came with about 25% plus spares (US found that 10% wasn't anywhere near enough - even though they were told early that it wasn't)). MakerDue can you drop me a PM with what you are actually researching I may have some data for you

Buz

Attached is a copy of a page from wartime USAAF Tech Order 00-25-4, Engine Time Between Overhaul.
The V-1710 was approved for 500 hours, with one extension.
Certainly, environmental and operational factors would affect the lifetime of any specific engine.
Dan

 

[GregP]

Attached is a copy of a page from wartime USAAF Tech Order 00-25-4, Engine Time Between Overhaul.
The V-1710 was approved for 500 hours, with one extension.
Certainly, environmental and operational factors would affect the lifetime of any specific engine.
Dan

Very nice. What was the date on thath tech order, Dan?

 

[ddwhitney]

Very nice. What was the date on thath tech order, Dan?

TO 00-25-4, November 13, 1943

 

[MakerDude]

Attached is a copy of a page from wartime USAAF Tech Order 00-25-4, Engine Time Between Overhaul.
The V-1710 was approved for 500 hours, with one extension.
Certainly, environmental and operational factors would affect the lifetime of any specific engine.
Dan

Seems USAAF have way longer lifespans, thanks for the info!

 

[GregP]

Thanks, Dan!

 

[MIflyer]

In the book "Vees For Victory" it states that Allison established War Emergency Ratings for the V-1710-93 in the p-38. The WER rating showed 75 in Hg MAP and 1825 HP.
BUT Allison also stated that the engine was to be removed and replaced when a total time of 10 hours operation at WER had been accumulated. Also, the spark plugs were to be removed and replaced if WER operation was anticipated.

 

[GregP]

Most all piston engines that HAD a war emergency rating required special attention if it was actually used during operation. The Allison was remarkably tolerant of WER use in the field.

 

[ThomasP]

As far as I am aware, no V-1710-93 was ever fitted to the P-38.

Also as far as I am aware, no war-time V-1710 fitted to the P-38 was ever operationally rated over 1600 BHP at 3000 rpm at 60"Hg - WER or otherwise - using 130 grade fuel.

The -93 was fitted to the P-63A/C but was never operationally rated at 1800 BHP and 75"Hg.

Even post-war, the V-1710-140 series (~improved -93) fitted to the F-82E/F/G - with 115/145 grade fuel - had to use ADI to achieve 74"Hg in WER. They tried higher ratings than 3200 rpm at 65"Hg without ADI but the engines kept blowing their intake manifolds off and/or destroying pistons & rods.

F-82E restrictions - maneuver, loads, and engine using 115/145 grade fuel - from 1948