R2800 Engines for the B-17s/B-24s ? - Page 3 - Aircraft of World War II

pasoleati · 08-05-2007, 12:55 PM

Henning, I will check what the B-32 book by Wolf says as it has a manual extract on the topic. I waited soime 5 mins for the B-29 engineering manual to download, but I have up (the file is so huge).

Micdrow · 08-05-2007, 01:43 PM

Quote:

Originally Posted by pasoleati

I waited soime 5 mins for the B-29 engineering manual to download, but I have up (the file is so huge).

The file is about 13.2 meg so if you have dial up it will take you a while.

pasoleati · 08-05-2007, 05:51 PM

I have broadband, but it is the slowest available and the transfer rate seemed to be about 45 bytes/sec.

chuter · 08-22-2007, 03:16 PM

That single engine B17 is the engine test bed (five engine) pictured above it with the wing engines 'shopped out.

Going from four 1820s to 2800s (two or three - wouldn't want four) would reduce the safety factor: lose a 1820 and you have 75% of your power left lose a 2800 and you've lost 33% to 50%, a big deal on a long range strategic bomber. Four propellers, though a bit smaller and with less power, are going to be more efficient than two larger higher powered ones for long cruise climbs.

donsprl-kc97g · 10-31-2008, 10:26 PM

My first time on this site, here goes. I am an old fart, with most of my flight time behind round engines; my father was a ferry pilot and transition instructor in WWII, then to Australia on C-47's, then back to US on C-54's to the pacific. C-54's had the R-2000, the only operation bird to use that engine, as far as I know. I entered USAF Aviation Cadets in 1957, trained on T-34's, T-28A's, ( R1300) then to B-25's, R-2600's, ome of the last classes to fly the baker two bits. Then to KC-97G's, the the R-4360, corncob engines. To sort of sum up what everyone has been saying, an airframe has only so much stretch, and the 2800 for the 17/24 would be a bit much. Neither was "underpowered, althought the Air force, in its infinate wisdom, often overloads its birds. Case in point, the KC-97 was designed to fly at 153,000# max, we usually flew at 175,000 actual, 190,000 equivilent, or 200,000 for emergengy. Thank God I never had to go at 200,000!!! When I got out, I did some crop dusting behind R-985s, but the nice thing was, I flew a Howard 350 for about a year. The Howard 350/500, were cleaned up, plushed up, sexed up Lockheed PV-1/B-34 Ventura's, with R-2800's. The Ventura was the first airplane we had that could flat outrun the Zero. Fast, 300 kts tas at 50% power, burning 100 gph per engine. The 2800 was the best large piston engine ever built, with a tbo of 2400 hours in airline use. Yes, it was used for mostly fighters, P-47, P-61F6F, F7F, F-4U, but also the Martin B-26, Douglas A-26. After the war, the 2800 powered the DC-6, Convairs, and Martin twins. The DC-7 used the 3350, which became the most complicated piston engine ever produced, at 3500 hp, in the turo-compound version, with the power recovery turbine. About 1970, with the DC-6's and 7's being rapidly replaced by the new jets, look in Trade-a-Plane, and find lots of -7's, good, flyable, low time at $50,000, but a comparable -6 would be about $75,000, the higher cost because of the better engines. (You could also buy a good P-51 for about $50.000 back then)
To convert a -17 0r -24 to the 2800 would be a MAJOR mod, and slow down production. With the B-29 and B-32 coming, they didn't want to lose that much production.
FYI. the first B-17's flew with the 850hp Hornet, R-1690.
I work at the Aviation Museum of Kentucky here3 in Lexington, and we have a very good collection of engines, starting with the 1917 Lawrence Penguin, a Menasco, Crosley, Heath, Mawen rotsary, very early 1340 Wast, cutaway -3350 off a B-29, a R-4360, Packhard build Merlin, R.R. Dart. and a bunch of those suck and blow things, including a F-117 engine that flew over Bagdsad during Desert Storm, and a bunch of airplanes, including F-14 from VF-32 that holds the record for bombs dropped in one day ( 57 ). If you come on Wed, Sat, or Sun, I.D. yourself to me and get a big discount. ( Our website, aviationky.org. sucks)
I got on this site looking for something that maybe one of yoiu guys out there can help me with. I need some good photos of both front and rear cylinders of a R-2800; I am doing the prelim work to build a model, about 1/6th scale, ala Williams Bros Wasp type. I am willing to buy them, if anyone has some. Thanks for any help on this.
Be careful out there, and remember, the three most usless things in the world, when things are turning brown, are the runway behind you, the altitude above you, and the fuel you have already used. Don Sproule

syscom3 · 11-01-2008, 12:00 AM

Welcome to the forum and one nice "first" post you have!

Have any pics from your flying days? Many people here would appreciate it!

Speaking of KC-97's ..... I posted a bunch of pics I took of the March AFB KC97. I will look up the thread and post it again.

kool kitty89 · 11-02-2008, 12:39 AM

A couple other notes, the R-2600 couldn't be practically turbocharged, severral seperate attempts were made (by Republic on the XP-44 after the failure of the R-2180, and I believe on a version of the A-20) but in all cases the installation was bulky and problematic.

Additionally the B-17 already had a ceiling well above 30,000 ft (albeit the B-24 didn't) and the B-17F at 1,380 hp WEP at 25,000 ft could manage 325 mph.

Boeing B-17F Fortress

A couple other engines were probably possible, like the R-2000 (a simplified, bored out R-1830 Twin Wasp, and only slightly larger in diameter, and still much less than the Cyclone), or the R-2180. (though it seems to have been problematic, the later R-2180-E being a redesign using the R-4360's cylinders)

THe R-2600 would be a possibility if you wanted a low/medium altitude version, and with the removal of the turbocharging systems weight would probably be about the same (possibly lighter) and the R-2600 was the same diameter as the R-1820. (though the Twin Wasp was much slimmer)

On the R-2800, the Boeing Model 341, a precurser to the B-29, was designed with 4x 2000 hp R-2800's: Boeing XB-29 Superfortress

Ivan1GFP · 01-05-2009, 09:27 PM

A late entry into the game but here goes:

The R-2800 WAS tried in a B-25. (from WarbirdTech account)
The plane flew quite well and was about 75 mph faster in certain conditions. The problem was that on a low pass, both outter wing panels snapped off the aircraft and it did a splat killing all onboard. Project was dropped.

I believe similar things might have happened to a B-24 / B-17 modification.

It is a nice academic exercise to guess what might have happened, but I believe the USAAF knew what they were doing. The heavies had the altitude and range advantage. The mediums did the low altitude, short / medium range work. I am surprised no one mentioned the A-20 for a low altitude speed demon.

- Ivan.

Shortround6 · 07-01-2009, 06:38 AM

Something that few have seemed to mention is that the R-2800s weighed more than the smaller engines, needed bigger props and cowlings etc. which would have run up the installed weight. Plus either bigger turbos or twin turbos).This would lead to weight and balance issues at least. Perhaps they could be solved. But then you have the aircraft gross weight problem. At a fixed gross weight (dictated by aircraft structual strength) the bigger powerplants can only be installed at the expense of payload ie. fuel, bomb load, defensive armament.
The original B-17 (Boeing 299) grossed 43,000lb with the 750HP Hornet engines and no turbos. The B-17C (Boeing 299H) with the 1200HP Cyclones grossed 49,650lb. That they were abale to stretch this aircraft to 72,000lbs in MAX. overlad conditon is amazing. BUt there may have been a limit as to how far it could be stretched. There is aslo the question of landing weights and would the plane need beefer landing gear. And the engine out situation. IF the plane lost both R-2800s on one side would it need a larger tail retain control/stability considering the larger porps and cowling ahead of the center of aerodyanic pressure?

Aaron Brooks Wolters · 08-27-2009, 08:33 PM

I know very little about aircraft engines except for what I can read and the one thing you never see a rating on is the torque of these motors. I'd be willing to bet that the 2800 is a torque monster which would have a dramatic effect on an airframe not designed for it. Just a thought.

10-31-2008, 10:26 PM	#35
donsprl-kc97g Junior Member Join Date: Oct 2008 Posts: 1	R-2800's for B-17/24 My first time on this site, here goes. I am an old fart, with most of my flight time behind round engines; my father was a ferry pilot and transition instructor in WWII, then to Australia on C-47's, then back to US on C-54's to the pacific. C-54's had the R-2000, the only operation bird to use that engine, as far as I know. I entered USAF Aviation Cadets in 1957, trained on T-34's, T-28A's, ( R1300) then to B-25's, R-2600's, ome of the last classes to fly the baker two bits. Then to KC-97G's, the the R-4360, corncob engines. To sort of sum up what everyone has been saying, an airframe has only so much stretch, and the 2800 for the 17/24 would be a bit much. Neither was "underpowered, althought the Air force, in its infinate wisdom, often overloads its birds. Case in point, the KC-97 was designed to fly at 153,000# max, we usually flew at 175,000 actual, 190,000 equivilent, or 200,000 for emergengy. Thank God I never had to go at 200,000!!! When I got out, I did some crop dusting behind R-985s, but the nice thing was, I flew a Howard 350 for about a year. The Howard 350/500, were cleaned up, plushed up, sexed up Lockheed PV-1/B-34 Ventura's, with R-2800's. The Ventura was the first airplane we had that could flat outrun the Zero. Fast, 300 kts tas at 50% power, burning 100 gph per engine. The 2800 was the best large piston engine ever built, with a tbo of 2400 hours in airline use. Yes, it was used for mostly fighters, P-47, P-61F6F, F7F, F-4U, but also the Martin B-26, Douglas A-26. After the war, the 2800 powered the DC-6, Convairs, and Martin twins. The DC-7 used the 3350, which became the most complicated piston engine ever produced, at 3500 hp, in the turo-compound version, with the power recovery turbine. About 1970, with the DC-6's and 7's being rapidly replaced by the new jets, look in Trade-a-Plane, and find lots of -7's, good, flyable, low time at $50,000, but a comparable -6 would be about $75,000, the higher cost because of the better engines. (You could also buy a good P-51 for about $50.000 back then) To convert a -17 0r -24 to the 2800 would be a MAJOR mod, and slow down production. With the B-29 and B-32 coming, they didn't want to lose that much production. FYI. the first B-17's flew with the 850hp Hornet, R-1690. I work at the Aviation Museum of Kentucky here3 in Lexington, and we have a very good collection of engines, starting with the 1917 Lawrence Penguin, a Menasco, Crosley, Heath, Mawen rotsary, very early 1340 Wast, cutaway -3350 off a B-29, a R-4360, Packhard build Merlin, R.R. Dart. and a bunch of those suck and blow things, including a F-117 engine that flew over Bagdsad during Desert Storm, and a bunch of airplanes, including F-14 from VF-32 that holds the record for bombs dropped in one day ( 57 ). If you come on Wed, Sat, or Sun, I.D. yourself to me and get a big discount. ( Our website, aviationky.org. sucks) I got on this site looking for something that maybe one of yoiu guys out there can help me with. I need some good photos of both front and rear cylinders of a R-2800; I am doing the prelim work to build a model, about 1/6th scale, ala Williams Bros Wasp type. I am willing to buy them, if anyone has some. Thanks for any help on this. Be careful out there, and remember, the three most usless things in the world, when things are turning brown, are the runway behind you, the altitude above you, and the fuel you have already used. Don Sproule

11-01-2008, 12:00 AM	#36
syscom3 Senior Member Join Date: Jun 2005 Location: Orange County, CA Posts: 10,814	Welcome to the forum and one nice "first" post you have! Have any pics from your flying days? Many people here would appreciate it! Speaking of KC-97's ..... I posted a bunch of pics I took of the March AFB KC97. I will look up the thread and post it again. __________________ "Pilot to copilot..... what are those mountain goats doing up here in the clouds?"

11-02-2008, 12:39 AM	#37
kool kitty89 Senior Member Join Date: Aug 2007 Location: San Jose, CA Posts: 2,412	A couple other notes, the R-2600 couldn't be practically turbocharged, severral seperate attempts were made (by Republic on the XP-44 after the failure of the R-2180, and I believe on a version of the A-20) but in all cases the installation was bulky and problematic. Additionally the B-17 already had a ceiling well above 30,000 ft (albeit the B-24 didn't) and the B-17F at 1,380 hp WEP at 25,000 ft could manage 325 mph. Boeing B-17F Fortress A couple other engines were probably possible, like the R-2000 (a simplified, bored out R-1830 Twin Wasp, and only slightly larger in diameter, and still much less than the Cyclone), or the R-2180. (though it seems to have been problematic, the later R-2180-E being a redesign using the R-4360's cylinders) THe R-2600 would be a possibility if you wanted a low/medium altitude version, and with the removal of the turbocharging systems weight would probably be about the same (possibly lighter) and the R-2600 was the same diameter as the R-1820. (though the Twin Wasp was much slimmer) On the R-2800, the Boeing Model 341, a precurser to the B-29, was designed with 4x 2000 hp R-2800's: Boeing XB-29 Superfortress Last edited by kool kitty89; 11-02-2008 at 02:49 AM.

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08-05-2007, 12:55 PM	#31
pasoleati Banned Join Date: Mar 2005 Posts: 44	Henning, I will check what the B-32 book by Wolf says as it has a manual extract on the topic. I waited soime 5 mins for the B-29 engineering manual to download, but I have up (the file is so huge).

08-05-2007, 05:51 PM	#33
pasoleati Banned Join Date: Mar 2005 Posts: 44	I have broadband, but it is the slowest available and the transfer rate seemed to be about 45 bytes/sec.

08-22-2007, 03:16 PM	#34
chuter Junior Member Join Date: Mar 2007 Posts: 6	That single engine B17 is the engine test bed (five engine) pictured above it with the wing engines 'shopped out. Going from four 1820s to 2800s (two or three - wouldn't want four) would reduce the safety factor: lose a 1820 and you have 75% of your power left lose a 2800 and you've lost 33% to 50%, a big deal on a long range strategic bomber. Four propellers, though a bit smaller and with less power, are going to be more efficient than two larger higher powered ones for long cruise climbs.

01-05-2009, 09:27 PM	#38
Ivan1GFP Senior Member Join Date: Mar 2008 Posts: 273	A late entry into the game but here goes: The R-2800 WAS tried in a B-25. (from WarbirdTech account) The plane flew quite well and was about 75 mph faster in certain conditions. The problem was that on a low pass, both outter wing panels snapped off the aircraft and it did a splat killing all onboard. Project was dropped. I believe similar things might have happened to a B-24 / B-17 modification. It is a nice academic exercise to guess what might have happened, but I believe the USAAF knew what they were doing. The heavies had the altitude and range advantage. The mediums did the low altitude, short / medium range work. I am surprised no one mentioned the A-20 for a low altitude speed demon. - Ivan.

07-01-2009, 06:38 AM	#39
Shortround6 Senior Member Join Date: Jun 2009 Posts: 787	Something that few have seemed to mention is that the R-2800s weighed more than the smaller engines, needed bigger props and cowlings etc. which would have run up the installed weight. Plus either bigger turbos or twin turbos).This would lead to weight and balance issues at least. Perhaps they could be solved. But then you have the aircraft gross weight problem. At a fixed gross weight (dictated by aircraft structual strength) the bigger powerplants can only be installed at the expense of payload ie. fuel, bomb load, defensive armament. The original B-17 (Boeing 299) grossed 43,000lb with the 750HP Hornet engines and no turbos. The B-17C (Boeing 299H) with the 1200HP Cyclones grossed 49,650lb. That they were abale to stretch this aircraft to 72,000lbs in MAX. overlad conditon is amazing. BUt there may have been a limit as to how far it could be stretched. There is aslo the question of landing weights and would the plane need beefer landing gear. And the engine out situation. IF the plane lost both R-2800s on one side would it need a larger tail retain control/stability considering the larger porps and cowling ahead of the center of aerodyanic pressure?

08-27-2009, 08:33 PM	#40
Aaron Brooks Wolters Senior Member Join Date: Jul 2007 Location: Abingdon, VA. Posts: 3,504	I know very little about aircraft engines except for what I can read and the one thing you never see a rating on is the torque of these motors. I'd be willing to bet that the 2800 is a torque monster which would have a dramatic effect on an airframe not designed for it. Just a thought.