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Dumb question of the day: what did the Connie use?
R2800 Engines for the B-17s/B-24s ?
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Dumb question of the day: what did the Connie use?
FLYBOYJ
"THE GREAT GAZOO"
Turbo Coumpounds, 3350s..
Hi Flyboyj,
>The R2800 for the most part was considered a "fighter engine."
Hm, are you sure about that? It seems to have been used in the C-46 and and the B-26, among others.
But I guess I should have had a closer look at the actual power ratings before posting: The R-3350 yielded 2080 HP at optimum altitude at maximum continous power, while the R-2800(-21) provided just 1625 HP, though it was capable of a comparable peak output.
Regards,
Henning (HoHun)
>The R2800 for the most part was considered a "fighter engine."
Hm, are you sure about that? It seems to have been used in the C-46 and and the B-26, among others.
But I guess I should have had a closer look at the actual power ratings before posting: The R-3350 yielded 2080 HP at optimum altitude at maximum continous power, while the R-2800(-21) provided just 1625 HP, though it was capable of a comparable peak output.
Regards,
Henning (HoHun)
FLYBOYJ
"THE GREAT GAZOO"
Hi Flyboyj,
>True - also look at fuel consumption at altitude, that has a lot to play in it as well....
R-2800-21 at 1625 HP at 26000 ft: 210 gallons per hour
R-3350 at 1630 HP at 26000 ft: 152 gallons per hour
Hm, quite amazing. The R-2800 is not that much more thirsty than the R-3350 if you compare the most economic settings, but it sure gulps the fuel if it's run at high power.
Regards,
Henning (HoHun)
>True - also look at fuel consumption at altitude, that has a lot to play in it as well....
R-2800-21 at 1625 HP at 26000 ft: 210 gallons per hour
R-3350 at 1630 HP at 26000 ft: 152 gallons per hour
Hm, quite amazing. The R-2800 is not that much more thirsty than the R-3350 if you compare the most economic settings, but it sure gulps the fuel if it's run at high power.
Regards,
Henning (HoHun)
syscom3
Pacific Historian
with a 60 gal/hr difference, multiply that by four, and the fuel consumption for a 4 engined bomber become excessive.
FLYBOYJ
"THE GREAT GAZOO"
BINGO!!!!!!!
Hi Pasoleati,
>Henning, what are your sources for fuel consumption? Is that R-3350 setting perhaps at auto-lean mixture vs. R-2800´s auto rich?
"Airplane Commander Training Manual for the Superfortress", with the scan of the relevant cruise chart found here:
http://www.ww2aircraft.net/forum/aviation/mission-moscow-hypothetics-8720.html
For the R-2800-21, it's the P-47 Specific Engine Flight Chart for the R-2800.
If I read the B-29 chart correctly, it's Auto Rich just like the R-2800.
One of the reasons I asked was that the B-29's flight enginner manual had much higher specific fuel consumption figures for the type (or maybe I read the diagram incorrectly), which I found surprising. This manual can be found here:
http://www.ww2aircraft.net/forum/ot...tech/b-29-engineering-flight-book-8691-3.html
Regards,
Henning (HoHun)
>Henning, what are your sources for fuel consumption? Is that R-3350 setting perhaps at auto-lean mixture vs. R-2800´s auto rich?
"Airplane Commander Training Manual for the Superfortress", with the scan of the relevant cruise chart found here:
http://www.ww2aircraft.net/forum/aviation/mission-moscow-hypothetics-8720.html
For the R-2800-21, it's the P-47 Specific Engine Flight Chart for the R-2800.
If I read the B-29 chart correctly, it's Auto Rich just like the R-2800.
One of the reasons I asked was that the B-29's flight enginner manual had much higher specific fuel consumption figures for the type (or maybe I read the diagram incorrectly), which I found surprising. This manual can be found here:
http://www.ww2aircraft.net/forum/ot...tech/b-29-engineering-flight-book-8691-3.html
Regards,
Henning (HoHun)
Attachments
FLYBOYJ
"THE GREAT GAZOO"
I actually think he meant DC4 and DC6. The DC4 used R2000s, the 6 used R-2800s. It was the DC7 that used 3350s.
The file is about 13.2 meg so if you have dial up it will take you a while.
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.
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
Recruit
- 1
- Oct 31, 2008
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
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
Pacific Historian
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.
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
Senior Master Sergeant
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
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
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.
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
Major General
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?
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
Brigadier General
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.
