What was the problem with the allison engine?

[tomo pauk]

Well put, Messy1

 

[Lighthunmust]

I don't think the idea was as much of a mistake as was the understanding of the rate of advancement that was occurring at the time. When the B-17 was conceived, the proposed fighters at the time was not significantly faster than the bomber and defensive system would be more effective. However by the time the bomber was deployed, technology in fighters had significantly improved and implemented much faster than bomber advancements could. The concept of speed as an superior advantage for a bomber has never been disproved nor abandoned, starting with the amazing Mosquito. In the 50s, the Mig 15 had a devil of a time, and as far as I know never succeeded, trying to catch a B-47s, as they buzzed Russian airfields. This is would have also been true with the Mig 21 trying the catch the equally fast B-58, and the tri-sonic B-70 was killed by advancements in anti-aircraft missiles, not by a fighter threat.

The mistake is the same one made for millennia: failure to realize that every weapon creates a counter-weapon or countermeasure, the technology your are using on your weapon may be adapted for a counter-weapon or countermeasure. I agree with you on the comprehension of the rate of technological advance, but like the principles of Sun-Tzu from 2500 years ago, these basic principles never change. Just the failure to consider a vast use of the many methods of detection available without the benefit of radar should have been a factor for bomber design and doctrine. I don't think they really considered it and how it would enable a defender to have fighters up and waiting. Even without Radar I think the BoB would have ended the same way with only more time and bloodshed added. Obviously I have the benefit of hindsight, but the lack of foresight and respect for the ingenuity of opponents to develop countermeasures was in my opinion rife within the U.S. military and political sphere in the 1930s and continues today. By the way, I am ex-Army and ex-NSA analyst so I am not a hater of the U.S. Military.

I absolutely agree with you about the advantages of speed. The heavy defensive gun armament on bombers being on the losing side of history. Speed, Deception, and Stealth being the future. No doubt that Geoffrey de Havilland had better foresight than many planners of his day. There was a thread in 2005 about the Mosquito versus the B-17 that addressed this issue. Ultimately you fight with what you've got rather than what you might have had. Speed is not everything and not of unlimited availability. Many Mosquitos were shot down by fighter aircraft.

A RB-47 flying out of Alaska was scouting out the Kamchatka Peninsula on 17 April 1955, when it was bounced by Soviet MiG-15s in international airspace. The RB-47 and its crew disappeared. - wikipedia

I seem to recall from my reading about NSA, other RB-47s were lost to subsonic MiG-17s.

B-68s had limited endurance even at high altitude when using enough speed to out race a MiG 21. Even if the SAM were never invented it would have been in trouble facing the density of MiG defenders over hundreds of miles.

The same is true of the B-70. The problem is just more difficult for the defender, but not insurmountable for a nation structured as the USSR was. A dense defense of MiG-25s would have been created. I think the B-70 system would have been eventually killed by a fighter threat. I think there is a reason besides treaty and satellites why deep over flights of the USSR with SR-71s didn't happen. Detection technology was advancing about as fast as aviation technology. Not just radar, but detection using a wide spectrum of the EM band. Sometimes the most up to date technology is not the answer. If I recall correctly the Serbs shot down a F-117 using an old radar system that probably nobody designing the F-117 expected to encounter.

Much appreciation for davapir for creating this thread and the great posts the participants are making. I should have "Vees for Victory" and the other two engine books I ordered by next week. Your posts are only making my eager anticipation grow.

 

[Readie]

Popular Science - Google Books

I found this on line.
Cheers
John

 

[Lighthunmust]

Popular Science - Google Books

I found this on line.
Cheers
John

Bravo! I have been bookmarking these sites you are posting. Oh how I wish that most of my pre-1993 book and magazine collection had not been "lost" by the movers. I had a bunch of National Geographics from the 30s-60's that had articles like this one. Thank you John.

 

[Readie]

Bravo! I have been bookmarking these sites you are posting. Oh how I wish that most of my pre-1993 book and magazine collection had not been "lost" by the movers. I had a bunch of National Geographics from the 30s-60's that had articles like this one. Thank you John.

Thanks Steve, like you my collection of old mags and encyclopaedic materials that covered article like my post as all long gone. I search ebay daily trying to rebild it but, its a tall order.
Cheers
John

 

[Messy1]

Popular Science - Google Books

I found this on line.
Cheers
John

Great link. Excellent article. Thanks for sharing Is there a way to print those articles off?

 

[davparlr]

Many Mosquitos were shot down by fighter aircraft.

Sill, the Mosquito was an effective high speed bomber depending on speed only.

A RB-47 flying out of Alaska was scouting out the Kamchatka Peninsula on 17 April 1955, when it was bounced by Soviet MiG-15s in international airspace. The RB-47 and its crew disappeared. - wikipedia

I seem to recall from my reading about NSA, other RB-47s were lost to subsonic MiG-17s.

Again, the B-47 was able to effectively operate over enemy airspace for many years with very few losses using speed, and some help from a pair of 20 mm cannons. The clear message to the Russians, B-47s with nukes could do the same thing.

B-68s had limited endurance even at high altitude when using enough speed to out race a MiG 21. Even if the SAM were never invented it would have been in trouble facing the density of MiG defenders over hundreds of miles.

The defensive systems of Russia at this time, 1960-69, are unknown to me but the B-47 was making penetrations only a few years before. Also unknown to me is the status of the electronic defensive systems of the B-58, assuming it was working. Also, with ICBMs leading the charge, it would be expected that confusion would be rampant in Russia. All in all, I believe the defensive status of the USSR during the 60s was overstated. I suspect there were many holes to fly through. And plane for plane, the Mig 21 would have a hard time catching a B-58.

The same is true of the B-70. The problem is just more difficult for the defender, but not insurmountable for a nation structured as the USSR was. A dense defense of MiG-25s would have been created. I think the B-70 system would have been eventually killed by a fighter threat. I think there is a reason besides treaty and satellites why deep over flights of the USSR with SR-71s didn't happen. Detection technology was advancing about as fast as aviation technology. Not just radar, but detection using a wide spectrum of the EM band. Sometimes the most up to date technology is not the answer. If I recall correctly the Serbs shot down a F-117 using an old radar system that probably nobody designing the F-117 expected to encounter.

All of this is true but we were talking about bomber speed verses fighter speed. In this situation, the B-70 could cruise at 3+ mach and the Mig 25 2.8 mach, it could go faster but the pilot would likely have to bail out. It was also a prodigious consumer of fuel and had a limited combat radius, especially if it was trying to catch an extremely fast foe. Being slower and having to anticipate the direction of the incoming bomber in order to launch in the correct direction and having limited loiter time would make interception problematic. Of course, radar and missiles make a big differences as does defensive electronic countermeasures.

Much appreciation for davapir for creating this thread and the great posts the participants are making. I should have "Vees for Victory" and the other two engine books I ordered by next week. Your posts are only making my eager anticipation grow.

I have always been impressed with the corporate knowledge expressed by the participants of this website. After a lifetime of studying aircraft, reading everything I could get my hands on, spending time in the AF, and working at Northrop Grumman for 29 years, I am always amazed by what I don't know.

 

[Lighthunmust]

Sill, the Mosquito was an effective high speed bomber depending on speed only.

I agree. It was very effective. My great-uncle flew one and is still alive.

Again, the B-47 was able to effectively operate over enemy airspace for many years with very few losses using speed, and some help from a pair of 20 mm cannons. The clear message to the Russians, B-47s with nukes could do the same thing.

The RB-47 incursions were not very deep into Soviet air space, many times not even over land. They were missions to measure the EM emissions and response of the air defense forces.

The defensive systems of Russia at this time, 1960-69, are unknown to me but the B-47 was making penetrations only a few years before. Also unknown to me is the status of the electronic defensive systems of the B-58, assuming it was working. Also, with ICBMs leading the charge, it would be expected that confusion would be rampant in Russia. All in all, I believe the defensive status of the USSR during the 60s was overstated. I suspect there were many holes to fly through. And plane for plane, the Mig 21 would have a hard time catching a B-58

I agree it was overstated by the Soviets. Sometimes by the USAF leaders when it suited the purpose of getting funds for new toys. Certainly confusion would be the order of the day with ICBMs on the way. But the depth of defense in terms of numbers of aircraft and geography would be formidable. It would not be one MiG in tail chase, it would be swarms of MiGs with a geographical depth of defense. Many MiGs firing many missiles. I really think by the time the B-58 actually became operational it was on tenuous ground so to speak. It is my understanding that speeds above Mach 1 were restricted to the target run with very little fuel available for evasion into the target. I think many missions would be one way for no other reason than fuel depletion.

All of this is true but we were talking about bomber speed verses fighter speed. In this situation, the B-70 could cruise at 3+ mach and the Mig 25 2.8 mach, it could go faster but the pilot would likely have to bail out. It was also a prodigious consumer of fuel and had a limited combat radius, especially if it was trying to catch an extremely fast foe. Being slower and having to anticipate the direction of the incoming bomber in order to launch in the correct direction and having limited loiter time would make interception problematic. Of course, radar and missiles make a big differences as does defensive electronic countermeasures.

It would certainly be a tough nut for the Soviets to crack, but the B-70 would be facing a great many faster AAMs from even subsonic fighters strung along its flight path. I am sure there would even be MiG-25s attempting to ram.


I wonder if we should have saved all the money on high speed bombers and just used Cessnas. If I recall correctly, a teenager from Germany managed to penetrate Soviet air defenses all the way to Red Square.

I have always been impressed with the corporate knowledge expressed by the participants of this website. After a lifetime of studying aircraft, reading everything I could get my hands on, spending time in the AF, and working at Northrop Grumman for 29 years, I am always amazed by what I don't know.

The more I know, the more I know how little I know. The forum members are an incredible pool of collective knowledge and reality checkers.


P.S. How are you guys breaking up posts to create multiple quote balloons? I obviously haven't figured it out.

 

[wuzak]

Popular Science - Google Books

I found this on line.
Cheers
John

Interesting that the article shows an engine being turbocharged with two small turbines, one for each bank, driving a central double sided impeller.

Kinda like this picture from Flight Global of a turbocharged Merlin.

http://www.flightglobal.com/airspac...olls-royce-merlin-xx-supercharger-cutaway.jpg

Note that this doesn't have an engine stage mechanical supercharger. The air intake is pointed towards the rear, but could easily be pointed upwards for a top intake (like Allisons) or downwards for a bottom intake (like Merlins). The impeller and housing could be positioned so as to feed the eye of an engine stage supercharger, if so desired.

The intercooler (technically it is actually an aftercooler) is a liquid to air intercooler - an air to air intercooler would be larger.

But it does show that a turbocharged V12 aero engine could possibly have been turbocharged and used in a single engine fighter, without going to teh size and bulk of a P-47. Or it could have bene used in a multi engined aircraft like the Lancaster and Mosquito.

 

[wuzak]

P.S. How are you guys breaking up posts to create multiple quote balloons? I obviously haven't figured it out.

They would be using this

icon, then using Reply to Thread.

 

[Lighthunmust]

Thank you for the reply wuzak.

 

[wuzak]

Thank you for the reply wuzak.

Your welcome. Unfortunately the icon didn't come up. But it is the quote mark with a + on the bottom right.

 

[Readie]

Interesting that the article shows an engine being turbocharged with two small turbines, one for each bank, driving a central double sided impeller.

Kinda like this picture from Flight Global of a turbocharged Merlin.

http://www.flightglobal.com/airspac...olls-royce-merlin-xx-supercharger-cutaway.jpg

Note that this doesn't have an engine stage mechanical supercharger. The air intake is pointed towards the rear, but could easily be pointed upwards for a top intake (like Allisons) or downwards for a bottom intake (like Merlins). The impeller and housing could be positioned so as to feed the eye of an engine stage supercharger, if so desired.

The intercooler (technically it is actually an aftercooler) is a liquid to air intercooler - an air to air intercooler would be larger.

But it does show that a turbocharged V12 aero engine could possibly have been turbocharged and used in a single engine fighter, without going to teh size and bulk of a P-47. Or it could have bene used in a multi engined aircraft like the Lancaster and Mosquito.

Interesting, Thanks for posting that Wuzak. A Turbo Merlin eh? ummmmm.
I used to live in Ulverstone, Tas when I was a boy. Do you know that area?
Cheers
John

 

[Readie]

Great link. Excellent article. Thanks for sharing Is there a way to print those articles off?

I can get the 'print' icon up. If that doesn't work for you try to save the doc and then print it...
Usually its hard to print these items off as they want you to buy them lol.
Cheers
John

 

[wuzak]

Interesting, Thanks for posting that Wuzak. A Turbo Merlin eh? ummmmm.
I used to live in Ulverstone, Tas when I was a boy. Do you know that area?
Cheers
John

Yes, not that I have spent much time there.

 

[Readie]

Yes, not that I have spent much time there.

We left for Melbourne in 1964 so I can only recall parts. Google Earth is a great tool for visiting old haunts.The part where we lived doesn't seem to have changed much, I can still spot the cattle grid at the end of the drive !
Cheers
John

 

[billswagger]

It seems the Allison design left less room for "rectification" that other designs.

I also wonder what political agendas were being served at a time when most Allison engined aircraft were being shipped away on lend lease programs.
Even though they might be allies, why would the US ship similarly capable or better aircraft to foreign countries?
The idea of arming an ally with equally capable aircraft as your own might not be seen as a wise military decision considering isolationism had most countries looking out for themselves at the time the war was going on.
In some ways, the Allisons lack of development may have been because the aircraft were deemed hand me downs going to outside countries.
It may have been purposefully neutered.
There are other examples of front line fighters using limited technology as to not lose trade secrets when enemies capture aircraft.
Why would Allison (General Electric) care, they still make a grip on the gov't contract selling the engines.
The other reason, Packard had begun building better engines in the US and so much of the production was shifting toward their use instead of the Allison.
Allison just filled the gap until other factories ramped up.
IMO, they could've done much better.
Why they didn't seems to have been a political strategy.

 

[Lighthunmust]

Interesting that the article shows an engine being turbocharged with two small turbines, one for each bank, driving a central double sided impeller.

Kinda like this picture from Flight Global of a turbocharged Merlin.

http://www.flightglobal.com/airspac...olls-royce-merlin-xx-supercharger-cutaway.jpg

Note that this doesn't have an engine stage mechanical supercharger. The air intake is pointed towards the rear, but could easily be pointed upwards for a top intake (like Allisons) or downwards for a bottom intake (like Merlins). The impeller and housing could be positioned so as to feed the eye of an engine stage supercharger, if so desired.

The intercooler (technically it is actually an aftercooler) is a liquid to air intercooler - an air to air intercooler would be larger.

But it does show that a turbocharged V12 aero engine could possibly have been turbocharged and used in a single engine fighter, without going to teh size and bulk of a P-47. Or it could have bene used in a multi engined aircraft like the Lancaster and Mosquito.

If I recall correctly a book or article I read years ago stated that the Merlin due to it's design was difficult to turbocharge. What do you know about this? Is it true? Did any aircraft use turbocharged Merlins?

 

[Shortround6]

I also wonder what political agendas were being served at a time when most Allison engined aircraft were being shipped away on lend lease programs.
Even though they might be allies, why would the US ship similarly capable or better aircraft to foreign countries?
The idea of arming an ally with equally capable aircraft as your own might not be seen as a wise military decision considering isolationism had most countries looking out for themselves at the time the war was going on.
In some ways, the Allisons lack of development may have been because the aircraft were deemed hand me downs going to outside countries.
It may have been purposefully neutered.
There are other examples of front line fighters using limited technology as to not lose trade secrets when enemies capture aircraft.
Why would Allison (General Electric) care, they still make a grip on the gov't contract selling the engines.
The other reason, Packard had begun building better engines in the US and so much of the production was shifting toward their use instead of the Allison.
Allison just filled the gap until other factories ramped up.
IMO, they could've done much better.
Why they didn't seems to have been a political strategy.

Or, it could be just as you said. Allison was so busy trying to get production going in 1940-41 they didn't have much effort to spare in developing the engine (specifically supercharger).

Allison went from 530 employees in 1938 to 786 in 1939 to 4,303 in 1940 to 9,673 in 1941 to 14,323 in 1942.

Engines delivered went from 13/14 (one was a V3420) in 1938 to 48 in 1939 to 1153 in 1940 (342 to the AAC) to 6,433 in 1941 to 15,319 in 1942.

At this point, Allison was behind the curve and trying to catch up. A number of projects had been on the back burner and slipping.

Please remember that Allison, Wright and P&W and each only started to design their own superchargers in 1936-38. There was no background of experience to fall back on.

 

[wuzak]

If I recall correctly a book or article I read years ago stated that the Merlin due to it's design was difficult to turbocharge. What do you know about this? Is it true? Did any aircraft use turbocharged Merlins?

Not sure that anybody actually tried.

Rolls-Royce had experimented with turbochargers, but had also determined that the exhaust thrust was significant, and they preferred to use the exhaust thrust. Th effect became more significant the faster the plane flew and the higher the altitude.