Two stage V-1710: looking for good airframes

[GregP]

Hi Shortround, to answer one of your questions, let's see … the 1,425 HP / 1,600 WER engines were used in the P-38H, J, K, L, M, the XP-60A, XP-60B, and XB-38. The 1,150 HP / 1,470 WER engine as used in the P-51 and P-51A. these were all F-series engines.

The G-series were used in the P-82's and XC-114 (Allison engined C-54). The -143 made 1,600 HP for takeoff and 1,700 HP at 21,000 feet.

To comment on another, the Wright R-2600 had a dry weight of over 2,000 pounds. The Allison dry weight was a bit over 1,350 pounds. So, the 1,600 HP from the Wright was dragging a LOT more airplane with more drag around than was the Allison making somewhat less HP with less drag.

I'll take the Allison.

 

[RpR]

Gentlemen:
I have read this site on occasion when a search engine listed this site as having the subject I was searching for, real often the XP-40Q.
This is a most interesting site and I am glad you gents contribute information that as a youth I had to search many books in the librarys for, now available a the tips of one's fingers.
Anyway: as to the topic of this thread.

It would be nice if some one would put one of the multi-stage Allisons into a P-40 and see how well it would go.

At the same time, it would be interesting if one would take one, or more of the P-40 frames and do an A: cut airframe as on the bubble canopy P-40N prototype and B: do a couple of full on XP-40Qs, with one aimed at Reno.
In my opinion, no aircraft is more derserving of hot Allison than a P-40 of any type.

 

[GregP]

Welcome Rob!

I agree! We did have one friend run his P-40 in 2010 in the Bronze and he beat a Corsair!

We run a shop in Rialto, CA that specializes in the Allison V-1710 and have many satisfied customers world wide, and a P-4Q would be really neat, I agree. Not likely, but would definitely be neat.

These days, the P-40 is more rare than the P-51, and is worth potentially more money, so an owner isn't likely to cut one up, but it WOULD be neat.

 

[Shortround6]

Hi Shortround, to answer one of your questions, let's see … the 1,425 HP / 1,600 WER engines were used in the P-38H, J, K, L, M, the XP-60A, XP-60B, and XB-38. The 1,150 HP / 1,470 WER engine as used in the P-51 and P-51A. these were all F-series engines.

The G-series were used in the P-82's and XC-114 (Allison engined C-54). The -143 made 1,600 HP for takeoff and 1,700 HP at 21,000 feet.

To comment on another, the Wright R-2600 had a dry weight of over 2,000 pounds. The Allison dry weight was a bit over 1,350 pounds. So, the 1,600 HP from the Wright was dragging a LOT more airplane with more drag around than was the Allison making somewhat less HP with less drag.

I'll take the Allison.

I would too, in 1944/45, which is rather late for a proposed "American Mosquito" or hot rod A-20.

The weight comparison is also a little off. It doesn't include the radiators and coolant for the Allison, add 250-400lbs. For the 1425hp versions in the " P-38H, J, K, L, M, the XP-60A, XP-60B, and XB-38" please add the weight of the turbo installation.

Two stage Allison went around 1600lbs dry.

The 1700hp R-2600 "B" series gained less than 50lb over the "A" and were still under 2000lbs. They were used in A-20 H K models. By the time the hot rod Allisons (the "G"s) show up 1900hp R-2600 "BB" models have been around for a couple of years, just over 1000 delivered in 1943, 1450hp Military at 15,000ft and 1350hp max continuous at 14,800ft. Weight 2045lbs.

By 1943 the A-20 was a dead end, the A-26 has already flown and first production model delivered in Aug, let alone be on the drawing boards.

 

[wuzak]

The A-20 was a bit bigger than the Mosquito. So to get comparable performance you would need more powerful engines. That's why I suggested the Vulture - they would comfortably fit on the A-20's firewalls, especially if annular radiators were used, and was in production in 1939/40. I know the Vulture had issues, But the power and the consumption figures were similar to the R-2600.

 

[tomo pauk]

Hi, SR6,

1900hp R-2600 "BB" models have been around for a couple of years, just over 1000 delivered in 1943, 1450hp Military at 15,000ft and 1350hp max continuous at 14,800ft. Weight 2045lbs.

That's interesting.

By 1943 the A-20 was a dead end, the A-26 has already flown and first production model delivered in Aug, let alone be on the drawing boards.

With 1900 HP R-2600 would it really be a dead end? Or, indeed, with R-2800? And more so - dead end in in 1943?

 

[Shortround6]

It was a dead end as far as further extensive modifications. The A-26 was delayed for a number of reasons, I don't have any real details but the prototype flew on July 10th 1942 and a full scale mock up had been inspected back in April of 1941. Spending thousands of engineering and drafting hours on a "modified" A-20 in 1943 doesn't make much sense unless you KNOW that any and all alternatives are complete turkeys (failures). Your own A-26, the P-61 as a night fighter/intruder, an Army version of the F7F and so on. This does not mean that the A-20 was not a useful airplane in 1943/44 with important work still to do. Just that any major modifications would delay other Douglas aircraft to no real purpose.

Sticking R-2800s on an A-20 airframe probably required too much re-work, after all the first few hundred built to French and British orders had R-1830 engines.

Think of the A-26 as Douglas's idea of an A-20 with R-2800 engines.

 

[tomo pauk]

It was a dead end as far as further extensive modifications.

Okay, I understand now what you were thinking. That puts it into a basket with most of the combat planes in service in 1943?

As for

Spending thousands of engineering and drafting hours on a "modified" A-20 in 1943

That surely would not be the case with trying to fit a more powerful variant of the R-2600? Was it really so that over 1000 of the 1900 HP R-2600s were delivered in 1943?

 

[Shortround6]

That surely would not be the case with trying to fit a more powerful variant of the R-2600? Was it really so that over 1000 of the 1900 HP R-2600s were delivered in 1943?

Fitting the 1900 HP R-2600s would be much less of a chore, minor details need working out. Of those 1000 engines delivered in 1943 850 were delivered in the last 3 months. I believe (but could be wrong) that they were going to the Curtiss SB2C. Engine delivered to airframe factory may mean the complete airplane does not reach a combat front for several more months.

Production of an A-20 with the 1900hp engine would overlap initial production of the A-26. "The first of five A-26B-1-DL Invaders appeared in September of 1943" Why it took so long to get into combat I don't know.

 

[tomo pauk]

It took until Sept 1944 to get them into service, a full group being in service in November 1944. Looks like there was plenty of time (all of the fair weather part of 1944) for the 2 x 1900 HP A-20 to take a part in the war.

 

[GregP]

Can't agree with you Shortround.

The R-2600-14 had a dry weight of over 2,000 pounds and the -13 was 1,980 pounds. The engine mount added maybe 50 pounds as you say, but radials consume WAY more oil than liquid-cooled inlines and the oil tank added over 300 pounds alone to the firewall (mostly mounted there). Oil tanks for the inles were half the weight or less.

Yes, they DO have a radiator and associated lines, but the installed weight of an Allison V-1710 is many hundreds of pounds less than the installed weight of an R-2600, and the associated airframes are lighter, too, and less draggy.

Inlines can cruise at 75% power all day long. Radials can't. Why do you think the B-17 was capable of 300+ mph but cruised at 180 mph? Ditto the hellcat and Bearcat, etc. They typically cruise at low rpm and low power, and accelerate when required for the mission. The inlines cruised over the faster than most comparable radial powered planes. By way of example, the F6F Hellcat could make 375 mph, but cruised at 200 mph. The Curtiss P-40E could only make 360 mph, but cruised at 270 mph. Other inline –to-radial comparison are similar.

The 2-stage Allison was only about 200 pounds heavier than the single-stage unit. I might add that our shop HAS two Allison aux-stage blowers and I know what I'm talking about since I have picked one up and have examined it up close an personally.

Like I said, I'd take the Allison anytime from early 1943 onward. Over the Pacific, I'd take the radial for a single engine plane and the Allison for a twin. It's no use talking about what-ifs in 1941 or 1942 … we didn't enter the war until basically early 1942 and needed some time to go to war, as does everyone who goes to war.

So, I suppose we'll have to agree to disagree on this one. Cheers.

 

[Shortround6]

The R-2600-14 had a dry weight of over 2,000 pounds

The -14 was experimental model intended for the XF7F and never produced in quantity or perhaps, never even flown.

and the -13 was 1,980 pounds. The engine mount added maybe 50 pounds as you say,

The -13 was a 1700hp "B" version and the 1980lbs is certainly close enough. I don't believe I said anything about engine mounts.

Yes, they DO have a radiator and associated lines, but the installed weight of an Allison V-1710 is many hundreds of pounds less than the installed weight of an R-2600, and the associated airframes are lighter, too, and less draggy.

Yes the Allison as installed is hundreds of pounds light but the difference is several hundred pounds less than a comparison of the dry weights would indicate. It is a little hard to compare associated airframes as the R-2600 was only used on single and twin engine bombers except for the experimental XF6F-1 which was never going to be powered by an Allison. Allison powered SB2C and TBFs would have been in serious trouble needing every bit of the R-2600s power for take-off in loaded condition. Sticking a pointy nose on either one of them is like sticking lipstick on a pig.

Inlines can cruise at 75% power all day long. Radials can't.

In a word---BALDERDASH

Why do you think the B-17 was capable of 300+ mph but cruised at 180 mph? Ditto the hellcat and Bearcat, etc. They typically cruise at low rpm and low power, and accelerate when required for the mission. The inlines cruised over the faster than most comparable radial powered planes. By way of example, the F6F Hellcat could make 375 mph, but cruised at 200 mph. The Curtiss P-40E could only make 360 mph, but cruised at 270 mph. Other inline –to-radial comparison are similar.

Really???? to take your P-40 example
http://www.zenoswarbirdvideos.com/Images/P-40/P-40FOIC.pdf

Yes the P-40 can cruise at 270mph but certainly not "all day" it runs out of fuel pretty darn quick, sucking down 105-116 gallons an hour at that speed depending on altitude. It can get almost double the range on the same fuel by slowing to about 200mph, not exactly a big surprise. I THINK B-17s cruised at 180mph in order to reach the targets. You could "cruise" a B-17 somewhat faster but you used a lot more fuel.

http://www.zenoswarbirdvideos.com/Images/B-17/17FOIC.pdf

And so on. Cruise speeds were dependent on mission needs, Picking a particular cruise speed (like long range cruise) and comparing to another plane's tactical cruise or recommended cruise in enemy territory to make a point about a type of engine is misleading.

The 2-stage Allison was only about 200 pounds heavier than the single-stage unit. I might add that our shop HAS two Allison aux-stage blowers and I know what I'm talking about since I have picked one up and have examined it up close an personally.

I was using the figures in "Vees for Victory" and lets look at it again. Single stage Allison is about 1350lbs agreed? I said the two stage was about 1600lbs. You say the supercharger weighs about 200lbs, we are 50lbs apart. Did the supercharger in the shop have ALL of the associated parts like drive shafts and couplings? Or oil couplings, fittings? Brackets?
Late model Allisons used the 12 counter weight crankshaft which is 27lbs (?) heavier than the earlier crankshaft.

So, I suppose we'll have to agree to disagree on this one. Cheers.

considering that any two supposedly identical engines can vary in weight by several percent I am not going to get excited about a weight difference of 20-30lbs on a 1600lb engine.

 

[GregP]

Let's see. The Wright R-2600 used only on the XF6F Hellcat? I think you might have missed a few single engine planes … like the Grumman TBF Avenger (definitely mass produced, wouldn't you say? They built 9,839), Brewster SB2A Buccaneer (771 built … qualifies for mass production, I think), Curtiss SB2C Helldiver (definitely mass produced, wouldn't you say? They built 7,140), and Vultee A-31 Vengeance (definitely mass produced, wouldn't you say? They built 1,931).

To your balderdash I say Balderdash. Let's agree to disagree.

The R-2600 had 0.86 HP / lb. The V-1710 had 1.05 HP / lb. I'll take the Allison.

Regarding your claim of poor range, the P-40E could make 879 miles at 205 mph and 45% power, but could also make 606 miles at 310 mph and 75% power with 20 minutes at 100% rated power. Data from WWII Aircraft Performance (http://www.wwiiaircraftperformance.org/P-40/P-40E-Specifications_Performance.jpg). So, they'd give up 270 miles for a sacrifice of 105 mph in cruise speed. If the target fell within 600 miles, I'd opt for the faster cruise.

Again, I suggest we agree to disagree ... and let it go.

I still work on and run Allisons, and still fly behind R-2600's in a B-25. Never have gotten to ride in the TBF yet. I'll take an Allison from my own experience with them. Nothing wrong with a good R-2600, but the ones assembled these days are questionable since the guys doing these days aren't exatly familiar with the process and frequently get several piston rings upside down ... and then have buiilt a real oil guzzler. Assorted other issues arise, too. Ask Rod Lewis; he runs several R-2600's and has had severe oil use issues with upside down rings .. supposedly installed by knowledgeable people!

Ah well, gimme' an Allison ... at least if WE built it (Yancey Enterprises, Rialto, CA). If built by a guy in Pennsylvania, I'd opt for a Briggs and Stratton!

 

[Shortround6]

Let's see. The Wright R-2600 used only on the XF6F Hellcat? I think you might have missed a few single engine planes … like the Grumman TBF Avenger (definitely mass produced, wouldn't you say? They built 9,839), Brewster SB2A Buccaneer (771 built … qualifies for mass production, I think), Curtiss SB2C Helldiver (definitely mass produced, wouldn't you say? They built 7,140), and Vultee A-31 Vengeance (definitely mass produced, wouldn't you say? They built 1,931).

What part of " It is a little hard to compare associated airframes as the R-2600 was only used on single and twin engine bombers except for the experimental XF6F-1" didn't you understand?

Or don't you consider the Avenger, Buccaneer, Helldiver and Vengeance single engine BOMBERS.

 

[krieghund]

On the subject of installing a two stage V-1710...here's some excerpts from the XP-51J manual to go with my previously posted picture showing some of the components required to hook up to the V-1710-119 engine plus the Power Plant Chart

 

[GregP]

Thank you for making my point Shortround!

The R-2600 seems to be a good bomber engine. For a fighter, I'll take an Allison any day. If we're opening the subject to bombers, I can add a few mass-produced bombers with the R-2600 that could have been faster with Allison power, but that seems like a new subject, so I won't.

What part of "I'll take an Allison any day" do YOU not understand? I never said YOU have to want an Allison; I said I did. I don't care if you like them or not, and that is not aimed at anything hidden, just an opinion. Call it a personal preference for me since I work at a shop that ONLY builds Allison V-1710 engines.

Let it go Shortround, please. No more; we just disagree here and that is OK, I hope.

 

[Shortround6]

Thank you for making my point Shortround!

I didn't make your point.

I don't like you putting words in my mouth or twisting things and saying "we just disagree here and that is OK" so you get the last word.

This is my last reply to you.

 

[GregP]

I stated earlier that the aux supercharger weighed in around 200 pounds or less.

Seems I used to be a bit stronger than I am now since I got one out yesterday and moved it around. Seemed heavier than 200 pounds so I weighed it and it came in around 275 pounds. With oil in it, it might make 290 - 300 pounds or so, give or take a few pounds. I think an internal hydraulic suercharger would have been lighter, shorter, and would have worked just as well if not better. It never happened.

By internal, I mean a new accessory housing unit with both internal impellers in one housing, but possibly with external connections to an intercooler assembly.

So, I think around 1600 - 1620 pounds for an Aux stage Allison is reasonable.

We have two units ready for overhaul if anyone wants a high-altitude Allison. Most people these days flying an Allison stay low for airshows and for the freedom of not being under IFR flight rules when in their WWII-era fighter plane. Attacking clouds on your business or pleasure trip is more fun than boring holes in the sky straight and level. If I had one, I'd opt for the lower, more fun-filled routes, too.

Hi Shortround,

I completely agree with your post 37, only in reverse. Have a nice day since you seem to need one.

 

[Shortround6]

The conventional wisdom states that single stage V-1710 was a lousy performer above 15-20000 ft, due to numerous reasons. The 2 stage variant was better, but it never played a role in the outcome of the ww2. The main user, P-63, went to VVS, and records about the use are scarce.
So what airframe could put the two stage V-1710 into a good use? The performance* is 1150 HP at 22400 ft (military power), WER dry of some 1450 HP at sea level, WER wet 1800+ HP at sea level. Weight is comparable with single stage Griffon or 2 stage Merlin, but it's longer.

*for the engines available in late 1943/early 1944. Late 1944/early 1945 increases the altitude of mil power to 25000 ft

Going back to the original question the suitable airframes are ones that used similar sized/powered engines. The V-1710 was not going to replace R-2600 or R-2800 engines no matter what kind of supercharger is used on it. The bombers need all the power they can get for take-off but using WER for standard take-offs isn't a good thing. Using it for hot high take-offs or on a few especially short runways may be acceptable.

For airframes that could have used it:
Production of the P-51J would come too late but if the Merlin had come up short ( either in power output or production) a 2 stage Allison might have been a substitute in the B,C,D series.
Some form of the P-40 like the "Q" if the USAAF was really desperate.
Low altitude version of the P-38 if turbos were a problem?? Low altitude in respect to the Turbo P-38, not low altitude in respect to normal P-39s and P-40s.
Used in a Version of the B-17???
Fitting an intercooler would have helped the altitude performance but you need the room for it.
The V-1710 is only a substitute for engines offering 1200-1350hp for take-off without WER.