Comparative Study of B-17 vs B-24

[XBe02Drvr]

DerAdler,

I left yesterday AM to fly to EWR then on to JAX. Great museum, really enjoyed it!

Cheers,
Biff

Big Easy to the Sewr, just to get to Hickoryville? My condolences! Cruel and unusual is supposed to be unconstitutional. How does a single seater pilot stand it? I hardly ever fly anymore, as I detest cattlecars. And I don't fit in the seats.
Cheers,
Wes

 

[BiffF15]

Big Easy to the Sewr, just to get to Hickoryville? My condolences! Cruel and unusual is supposed to be unconstitutional. How does a single seater pilot stand it? I hardly ever fly anymore, as I detest cattlecars. And I don't fit in the seats.
Cheers,
Wes

I sit in 1R most of the time so the seat is comfortable along with a better than average view...

Post school back in session it's much easier until the holidays!

Cheers,
Biff

 

[muskeg13]

Anyone else read "Unbroken" by Laura Hillenbrand, the the account of WW2 B-24 Bombardier Louie Zamperini. I can't locate my copy of the book right now, but I recall Zamperini and his crewmates were very unhappy being saddled with B-24s instead of B-17s. Zamperini thought the B-24 was an unsafe abomination and an absolute dog to fly in. I guess crashing due to mechanical failure while looking for another B-24 lost to mechanical failure, then being stranded 47 days at sea without food or water, followed by several very rough years in Japanese POW camps could influence your opinion of the B-24.

 

[billrunnels]

the Germans would not ignore the B-17's and go ater the B-24's. This is a typical Ww 2 US mythical statement. The Germans were vectored in and then up to the individual Staffelkapitäns as to which bomber pulk's would be selected for the attacks

This statement does reflect some truth. We B-17 Crew Members were glad to see B-24 Aircraft in the Bomber Stream.The only bomber I saw explode was a B-24 coming off his drop over Berlin. Bandits had been reported in the area prior to the explosion. Our P-51 escort dropped their wing tanks, can still see the gas spilling out as they tumbled down and headed that way. Were gone about 15 minutes and picked us up following our drop at Zossen. My heart went out for that Crew. All this at 24,500 ft.

 

[airminded88]

This statement does reflect some truth. We B-17 Crew Members were glad to see B-24 Aircraft in the Bomber Stream.The only bomber I saw explode was a B-24 coming off his drop over Berlin. Bandits had been reported in the area prior to the explosion. Our P-51 escort dropped their wing tanks, can still see the gas spilling out as they tumbled down and headed that way. Were gone about 15 minutes. My heart went out for that Crew.

Vivid account Bill, thanks for sharing it with us.
On such encounter, did you get to see the P-51s pound on the German fighters or did they got away?

Cheers

 

[billrunnels]

Vivid account Bill, thanks for sharing it with us.
On such encounter, did you get to see the P-51s pound on the German fighters or did they got away?

Cheers

No I didn't see any encounter.

Vivid account Bill, thanks for sharing it with us.
On such encounter, did you get to see the P-51s pound on the German fighters or did they got away?

Cheers

No I didn't see any followup activity. We were approaching the IP for our South drop on Zossen German Headquarters located just South of Berlin. Were briefed for Berlin but target changed en route after receiving a report from the Underground that Hitler was to be there. As it turned out he was not.

 

[billrunnels]

From a General's point of view, yes, it would be smarter to produce more B24s than 17s. More bombload, longer range. On paper the war in Europe should be won far easier with the B24.

But as a crewman aboard either aircraft, the B17 was the mount of choice. More durable, more armament for your protection. And of course you have to throw in morale.

In my opinion I think they complemented each other quite well. Both were a necessity in the war over Europe.

In the Pacific, B24 all the way.

And more Altitude over the Target.

 

[Conslaw]

It seems to me that on balance, the B-24 was slightly inferior to the B-17 in the daylight bombing of Germany role. The B-24 was more versatile overall, and especially played a crucial role in closing the "Atlantic Gap" in the battle against U-Boats.

 

[JDCAVE]

My Father flew one operation at the controls of a B-24 Liberator during a brief stint with RAF coastal command. He said it flew like a cow. His words, not mine. He also flew a tour of 31 operations on Canadian built Lancaster X's, which he said was the finest aircraft he had ever flown as it handled softly and beautifully with light touches on the controls, even with 14,000 lbs of bombs. Dad in KB865, March, 1945.

Jim

 

[Big Jake]

Digging through old threads, I came across this gem and couldn't resist throwing in my $.02.
This comment had to have come from someone who's never looked at these two aircraft up close and personal.
I'm an aircraft mechanic by training and have done my share of sheet metal work, and have also worked in a manufacturing plant (aircraft weapons, not airframes) and have some grasp of the processes involved. I'm convinced a plant capable of producing 20K Liberators could NOT turn around and crank out the same number of Fortresses in the same amount of time. Structurally, the Lib looks like it was designed for ease and speed of construction. The sheet metal parts are large and simple, with a minimum of fussy details, and the main spar is a simple sheet metal box. The Fort, on the other hand, comes from an earlier generation in the evolution of large all metal monoplanes, and is full of little complexities, forgings, castings and a built up main spar fabricated of heavy sheet metal box members riveted together to form a truss. Hell for stout, but not cheap, quick, or easy to build. I betcha the structural parts count for a B-17 airframe is near twice what it is for a 24. Those with GA experience can relate to this. The B-24 is built like a Cherokee/Saratoga/Seneca, the B-17 like a Beech 18.
I got the privilege of making these observations onederful day when Collings was in town, and I got to turn a wrench on both birds, and then ride in them both.
Cheers,
Wes

As a flight engineer on and a maintainer of a B-17, and also as a retired aircraft structural engineer who is also familiar with the B-24, I fully agree with Wes's comment regarding the difference in the two types' structure. The B-24 structure is indeed much simpler than the B-17 and thus much easier to produce. I partially agree with his comment that the B-24 is built like a Cherokee/Saratoga/Seneca and the B-17 like a Beech 18 - true for the B-24 (in a way...) but the B-17 is built like the Brooklyn Bridge.

Jake

 

[XBe02Drvr]

the B-17 is built like the Brooklyn Bridge.

Aw, come on, Jake! A suspension bridge?? Like an Eindecker or a Deperdussin? How about the Bayonne Bridge instead? At least it's a truss structure, even if it is arched.
In mech school our airframes instructor led us through a discussion of rivet sizing and spacing, then sent us out to a Cherokee 6 on the ramp and asked us to measure and calculate what percentage it exceeded the FAA minimum requirements for rivet spacing. We were astounded to discover it exceeded minimums by zero percent! He looked at me (the only pilot in the class) and said: "Keep that in mind next time you're driving around in one of these things!".
BTW, welcome aboard the funny farm! Glad to have you with us. What B-17 are you on? Do you do engine work, or ship them out? What category airworthiness certificate does your Fort fly under?
Cheers,
Wes

 

[Barrett]

Ref. operational ceiling of the 17 v. 24. Reminds me that the RAFish chaps in Lancs, Halifaxes etc tended to cheer when they learnt that Stirlings were on the roster for Tonight's Mission. Reason being: the Air Ministry required that Shorts build the machine to fit the standard hangar, which limited wingspan, which limited wing area, which limited...well, you know.

Sidebar: I got to know Johannes Steinhoff tolerably well. He expressed no difference in discussing the 17 v. 24. I cited Jimmy Thach's wartime interview in which he said that if the GAF had adopted the USN overhead gunnery pass, daylight bombing would've ended in '43. JS agreed. he said the advantages were well known: bigger target to shoot at and semi-impossible to defend against. But the GAF lacked the fuel and resources to teach sufficient numbers of Jagdfliegern how to fly the pattern.

 

[airminded88]

Ref. operational ceiling of the 17 v. 24. Reminds me that the RAFish chaps in Lancs, Halifaxes etc tended to cheer when they learnt that Stirlings were on the roster for Tonight's Mission. Reason being: the Air Ministry required that Shorts build the machine to fit the standard hangar, which limited wingspan, which limited wing area, which limited...well, you know.

Sidebar: I got to know Johannes Steinhoff tolerably well. He expressed no difference in discussing the 17 v. 24. I cited Jimmy Thach's wartime interview in which he said that if the GAF had adopted the USN overhead gunnery pass, daylight bombing would've ended in '43. JS agreed. he said the advantages were well known: bigger target to shoot at and semi-impossible to defend against. But the GAF lacked the fuel and resources to teach sufficient numbers of Jagdfliegern how to fly the pattern.

Hi Barret, could you point me towards some additional reading about such tactic. Thank you in advance.

Cheers

 

[CAVU Mark]

I think there were some B-24s in England. Here are some. Ken was in England before the war started as a Consolidated tech rep and left after the war ended. These are pictures from his album.

 

[muskeg13]

More fuel for the fire...
Army Air Forces in World War II
Vol. VI: Men and Planes
Prepared Under the Editorship of
Wesley Frank Craven Princeton University
James Lea Cate University of Chicago

Chapter 6, AAF AIRCRAFT OF WORLD WAR II, pp.206-207


The B-17 and the B-24 inevitably invited comparison. Coming along four to five years after the B-17, the B-24 possessed an initial advantage. It carried a larger bomb load than the B-17 and could carry the load farther with a crew of the same size-ten men. Listed in the charts originally as having a range of 2,850 miles with a 2,500-pound bomb load, experience showed that it did have a longer reach than any other compering plane.53 It was this advantage that gave the B-24 the call over the B-17 for service in CBI and SWPA, where Kenney's Fifth Air Force used it for the 2,400-mile round trip attacks on Balikpapan in 1944,* and where regularly, if less spectacularly, it extended the coverage of overwater search. Against the German Air Force, however, combat experience showed the plane to be lacking in armament and armor. Attempts to remedy these and other short-comings increased the weight of the plane and altered flight characteristics in such a way as to render it less stable. Lt. Gen. James H. Doolittle, commanding the Eighth Air Force, made his preference for the B-17 clear in a letter of January 1945.54 By that date the increased range of the B- 17 some time since had robbed the B-24 of its chief advantage.55 Against the Luftwaffe, the capital enemy, the rugged and steady B-17 remained the natural pick.

 

[XBe02Drvr]

Attempts to remedy these and other short-comings increased the weight of the plane and altered flight characteristics in such a way as to render it less stable.

In my five minutes in the right seat of the B-24, I never did get the dang thing trimmed up to hold altitude and heading hands off. And that was in single flight with nothing else around. Later that day, in the B-17, flying tandem (not formation) with the Lib, it trimmed up steady as a rock, and kept station easily. And the Fort didn't have a large fuel tank in the fuselage right behind your head to act as a bullet magnet. I know which one I'd rather take into harm's way!
A late neighbor of mine was a B-24 pilot based in N Africa, early days in the MTO. D model, no nose turret. He said holding a tight box formation with a loaded plane was a bitch, and dangerous to boot. Midairs were all too common. He threw out the protocol they were trained under of "pilot drives, copilot sits on his hands and keeps his mouth shut", and went to flying with both hands on the yoke and calling power commands to the copilot and flight engineer. He also gave both of them as much "stick time" as could safely be done. A no-no by stateside rules, but cheap insurance to his way of thinking. During his tour he had three copilots "graduate" and become aircraft commanders when scratch crews had to be put together. He said that was unheard of at the time, since the general scheme of things was that pilots were pilots and copilots were copilots, and that was that.
Cheers,
Wes

 

[MakerDude]

With respect to the speed difference between the b-24 and b-17 I think I found one other factor - a but minor. The b-24 had PW R-1830, the b-17 Wright 1820's. According to specs both were turning out 1200 hp. However some differences between the 2. Note - figures are from Wikipedia so don't bet your life on them.
PW R-1830
Diameter: 48.03 in (1,220 mm)
Dry weight: 1,250 lb (567 kg)

Wright R-1820
Diameter: 54.25 in (1,378 mm)
Dry weight: 1,184 lb (537 kg)

The b-17 Wright's have a slight edge in weight, being 66 lbs lighter. However it is at a big disadvantage in diameter, 6.22 inches. This gives a frontal area increase of 27.5 percent, or 3.5 square feet per engine. I can't find data on the nacelle size, though I would expect it would be proportional to the engine. If we went by engines alone the b-17 has 3.5 x 4 = 14 square feet of drag the b-17 doesn't have for the same power.

 

[XBe02Drvr]

I can't find data on the nacelle size, though I would expect it would be proportional to the engine.

Don't forget, the B24 has cowl "cheeks" which house intercooler and oil cooler, so drag differences are not going to be directly proportional to engine diameters. Also, for most piston aircraft, INTERNAL cooling drag accounts for between 20 and 40℅ of total airframe drag. Air entering the B17 cowling flows around one set of cylinders and baffles and exits, whereas in the B24 it has to find its way through another set of cylinders and their associated baffles.
Now check out their fuselages. The B24J is an oval torpedo with only a windshield and two turrets to break the flow of air. The B17G has a chin turret, cheek guns, a (streamlined) doghouse type crew compartment, and various bumps and protrusions here and there. OTOH, the speeds you see on spec sheets aren't truly representative of combat conditions, as most missions were flown at grossly overloaded weights. Cruising at overload weight, with the resulting higher AOA, increases induced drag on the B24's Davis wing proportionally more than the B17's wider chord, more tapered wing. I think you'd find that the speed differential in combat use was less than the spec sheets would lead you to believe.
Having (briefly) flown both aircraft "hands on" (albeit at light weights), I can vouch for the B17 as a sweet and steady flyer, and the B24 as a nervous pig. The B24's narrow wing chord makes for a relatively narrow CG range, and I suspect we were loaded toward the aft limit, which tends to make any plane a little less steady.
Cheers,
Wes

 

[Shortround6]

Bombers are tough to figure.

as X XBe02Drvr has already mentioned the engine nacelles/cowlings were different.


B-24s had the intercooler in the engine nacelle with a big scoop on one side to feed it. the carb intake and oil cooler where on the other side.
B-17s had the intercooler or at least the intakes in the wing leading edges along with the carb intakes and oil cooler intakes.

Without knowing what the internal drag was for these air passages it is a bit tough to compare drag.

 

[MakerDude]

Don't forget, the B24 has cowl "cheeks" which house intercooler and oil cooler, so drag differences are not going to be directly proportional to engine diameters. Also, for most piston aircraft, INTERNAL cooling drag accounts for between 20 and 40℅ of total airframe drag. Air entering the B17 cowling flows around one set of cylinders and baffles and exits, whereas in the B24 it has to find its way through another set of cylinders and their associated baffles.
Now check out their fuselages. The B24J is an oval torpedo with only a windshield and two turrets to break the flow of air. The B17G has a chin turret, cheek guns, a (streamlined) doghouse type crew compartment, and various bumps and protrusions here and there. OTOH, the speeds you see on spec sheets aren't truly representative of combat conditions, as most missions were flown at grossly overloaded weights. Cruising at overload weight, with the resulting higher AOA, increases induced drag on the B24's Davis wing proportionally more than the B17's wider chord, more tapered wing. I think you'd find that the speed differential in combat use was less than the spec sheets would lead you to believe.
Having (briefly) flown both aircraft "hands on" (albeit at light weights), I can vouch for the B17 as a sweet and steady flyer, and the B24 as a nervous pig. The B24's narrow wing chord makes for a relatively narrow CG range, and I suspect we were loaded toward the aft limit, which tends to make any plane a little less steady.
Cheers,
Wes

Good points!

One question I have, if anyone knows is - speeds, service ceiling are for when fully loaded. I wonder what b-17, b-24 did after they dropped their bombs. Both would be minus there bomb loads and half their fuel. Obviously you know want to get away as fast as you can.