B-25 later models take-off and landing data tested

[Maty12]

Wasn't that specifically mentioned in the movie with Van Johnson and Spencer Tracy about the Doolittle Raid?

Both the film and the book, though in the book Lawson states he lowered and then decided to retract them. Something to do with being scared of crosswinds ripping them off/jamming them? Admittedly it's been several months since I've read the book. I've never checked the historical footage to make sure (not sure his takeoff is even on film), but don't see any reason for him to make this up so it's probably how it happened.
All aircraft did indeed taxi to the same point and follow the same line to avoid crashing into the bridge.

 

[FLYBOYJ]

Both the film and the book, though in the book Lawson states he lowered and then decided to retract them. Something to do with being scared of crosswinds ripping them off/jamming them? Admittedly it's been several months since I've read the book. I've never checked the historical footage to make sure (not sure his takeoff is even on film), but don't see any reason for him to make this up so it's probably how it happened.
All aircraft did indeed taxi to the same point and follow the same line to avoid crashing into the bridge.

I read the book many years ago and seen the movie a few times - didn't he (Ted Lawson) just forget to lower them?

I don't see a cross wind ripping off flaps on a B-25 unless VFE is extremely exceeded. From what I could see out of the flight manual VFE is 170 MPH. That would be a hell of a crosswind! Flaps are hydraulically driven, unless there is a failure in the flap track system or hydraulic actuator, I can't see how they could "jam."

 

[FLYBOYJ]

In reading some other articles on this, it seems Lawson had concerns about the gusting winds over the deck. He first had the flaps down but retracted them as a precautionary measure. When it was time to launch he forgot to put them back up.

 

[Maty12]

I read the book many years ago and seen the movie a few times - didn't he (Ted Lawson) just forget to lower them?

I don't see a cross wind ripping off flaps on a B-25 unless VFE is extremely exceeded. From what I could see out of the flight manual VFE is 170 MPH. That would be a hell of a crosswind! Flaps are hydraulically driven, unless there is a failure in the flap track system or hydraulic actuator, I can't see how they could "jam."

I wasn't too sure, but fortunately I had my copy of the book handy. Seems I half remembered it:

"I was on the line now, my eyes glued on the man with the flag. He gave me the signal to put my flaps down. I reached down and drew the flap lever back and down. I checked the electrical instrument that indicates the flaps were working. They were. I could feel the plane quaking with the strain of having the flat surface of the flaps thrust against the gale and the blast from the props. I got a sudden fear that they might blow off and cripple us, so I pulled up the flaps again and I guess the Navy man understood. He let it go and began giving me the signal to rev my engines" (page 70).

Whether or not there was a risk of them blowing off I don't know, Lawson was an Aeronautical Engineer so quite knowledgeable, but it seems to have been more a heat-of-the-moment concern. No one else had issues with their flaps, but it was certainly a stressful environment and I can't fault him for playing it safe. Why this was changed in the movie to them forgetting the flaps I have no idea.

In any case, I really should read the book again, it's been a while.

 

[Maty12]

In reading some other articles on this, it seems Lawson had concerns about the gusting winds over the deck. He first had the flaps down but retracted them as a precautionary measure. When it was time to launch he forgot to put them back up.

Correction: You are right, I just checked and it's right on page 76 that he reached down to raise the flaps only to find them already up. Seems I forgot that bit. I understood that originally as him having forgotten that he decided not to use the flaps, him just forgetting to lower them again for takeoff does make more sense.

 

[FLYBOYJ]

Whether or not there was a risk of them blowing off I don't know, Lawson was an Aeronautical Engineer so quite knowledgeable, but it seems to have been more a heat-of-the-moment concern. No one else had issues with their flaps, but it was certainly a stressful environment and I can't fault him for playing it safe.

In hindsight he probably had nothing to worry about but I think anyone sitting in his seat at that moment would have probably done the same thing.

 

[davparlr]

I wasn't able to do much research but I was wondering why so many crew, five, was needed. They certainly didn't need a copilot, unless there was a control that couldn't be reached (I don't know if any Brit bomber had a copilot, I know some didn't). They did need a bombardier/navigator. They didn't need any gunners or guns. Success was dependent on surprise. If surprise did not happen, gunners would have been of little use. If surprise is obtained, gunners most likely would not be needed. Every crew member is 25 gallons of gas, each machine gun is 14 gallons (x3 ?) 42 gallons total. So, with a pilot and navigator/bombardier, only fake machine guns total weight savings would allow 117 gallons of gas, with one additional crew added, fuel would be about 92 gallons. I don't know how flexible their fuel management, how easy would it be to add fuel, was, nor do I know the optimum fuel usage of the B-25, but 117 gallons of gas would have been helpful, even 92 would have helped. Also I didn't count the fact that .50 cal ammunition would not be needed and that is pretty heavy, I am sure. Also, for an extremely risky endeavor, much fewer men would be exposed.

 

[FLYBOYJ]

I wasn't able to do much research but I was wondering why so many crew, five, was needed. They certainly didn't need a copilot, unless there was a control that couldn't be reached (I don't know if any Brit bomber had a copilot, I know some didn't). They did need a bombardier/navigator. They didn't need any gunners or guns. Success was dependent on surprise. If surprise did not happen, gunners would have been of little use. If surprise is obtained, gunners most likely would not be needed. Every crew member is 25 gallons of gas, each machine gun is 14 gallons (x3 ?) 42 gallons total. So, with a pilot and navigator/bombardier, only fake machine guns total weight savings would allow 117 gallons of gas, with one additional crew added, fuel would be about 92 gallons. I don't know how flexible their fuel management, how easy would it be to add fuel, was, nor do I know the optimum fuel usage of the B-25, but 117 gallons of gas would have been helpful, even 92 would have helped. Also I didn't count the fact that .50 cal ammunition would not be needed and that is pretty heavy, I am sure. Also, for an extremely risky endeavor, much fewer men would be exposed.

True the Brits did away with co-pilots but more out of necessity, but I think in the bigger picture you had an element of "Cockpit Resource Management" and I would think having a co-pilot was an insurance policy, especially in a high profile mission. IMO there could have been way less non-combat accidents in Bomber Command if there was a dedicated co-pilot as part of the crew, and IMO an F/E didn't cut it, especially flying prehistoric instrument approaches.

As we know in the post war years a co-pilot or second pilot was SOP in most larger multi-engine aircraft.

As far as gunners - I think they (Doolittle) were expecting to be intercepted and wanted some means of defense. IIRC they only had a gunner in the top turret, put broom sticks in the tail of the aircraft

 

[Maty12]

True the Brits did away with co-pilots but more out of necessity, but I think in the bigger picture you had an element of "Cockpit Resource Management" and I would think having a co-pilot was an insurance policy, especially in a high profile mission. IMO there could have been way less non-combat accidents in Bomber Command if there was a dedicated co-pilot as part of the crew, and IMO an F/E didn't cut it, especially flying prehistoric instrument approaches.

As we know in the post war years a co-pilot or second pilot was SOP in most larger multi-engine aircraft.

As far as gunners - I think they (Doolittle) were expecting to be intercepted and wanted some means of defense. IIRC they only had a gunner in the top turret, put broom sticks in the tail of the aircraft

Seconded on the CRM comment, not to mention the sheer length of this mission, of which the Hornet to Japan leg was flown at tree-top level. The Raiders took off in the morning and reached China pretty close to nighttime, asking one pilot to fly for half the day is inviting disaster. As for the guns and gunners, the modified B-25s only had a nose gun and the top turret for defense, and the turrets came in handy because more than one aircraft were intercepted. I'm not sure we can say the raid would've gone as well without them. The bombardier and navigator were separate people in the early B-25s, there's only one dedicated gunner. Could bombardiers or navigators be trained to do each other's role for the mission, decreasing the crew by one member? Maybe, but workload again becomes an issue given how long the mission was.

 

[FLYBOYJ]

Seconded on the CRM comment, not to mention the sheer length of this mission, of which the Hornet to Japan leg was flown at tree-top level. The Raiders took off in the morning and reached China pretty close to nighttime, asking one pilot to fly for half the day is inviting disaster. As for the guns and gunners, the modified B-25s only had a nose gun and the top turret for defense, and the turrets came in handy because more than one aircraft were intercepted. I'm not sure we can say the raid would've gone as well without them. The bombardier and navigator were separate people in the early B-25s, there's only one dedicated gunner. Could bombardiers or navigators be trained to do each other's role for the mission, decreasing the crew by one member? Maybe, but workload again becomes an issue given how long the mission was.

Agree 100% With what was known (and unknown) and considering the technology of the day, I think adequate planning was undertaken. "What if" they did get bounced by a Zero? At least they had the means to somewhat defend themselves.

 

[davparlr]

[Q

I would think having a co-pilot was an insurance policy, especially in a high profile mission.

On mission success, maybe, against satisfactory instrument approaches, no. The actual known probability of crashing all planes before approach, 100% (except one in Russia) thus, no instrument approaches.

As far as gunners - I think they (Doolittle) were expecting to be intercepted and wanted some means of defense. IIRC they only had a gunner in the top turret, put broom sticks in the tail of the aircraft

You are probably right however the assumption was wrong. Like Pearl Harbor, surprise was critical to mission success. Few air engagements were experienced.

Seconded on the CRM comment, not to mention the sheer length of this mission, of which the Hornet to Japan leg was flown at tree-top level. The Raiders took off in the morning and reached China pretty close to nighttime, asking one pilot to fly for half the day is inviting disaster.

The added fuel would be good for an additional hour and half cruise, or about 240 miles, more than making up for the lost two hundred miles. The original mission took 13 hours. So the new mission would be 14 and half hours. I would bet that if Doolittle asked all his hand selected pilots if they could fly this mission, AND BOMB JAPAN, for 14.5 hours without a copilot, all would have said, "no, sweat". It would be a long and stressful mission with the initial part, flying low level, going to Japan, bombing Japan, is the hardest but also most pumped up with adrenalin. The last leg, going to China, uneventful and far less stressful, except watching the fuel gage, certainly would not be a problem with an autopilot (unknown if installed). But minor in any event. The navigational part of bombardier/navigator was definitely the most difficult and continuous effort and were specially trained. The bombardier part using the "Mark Twain" bomb aiming device, basically a protractor with a bar on it, would probably have taken about 10 minutes to be an expert.

Doolittle was looking at the loss of 100% of the aircraft, all crew member spread out over the ocean or mainly Japanese held land and the possibility of most of the crews killed or captured. Fortunately and amazingly most of the crews came back, but he didn't know that at the time. If he had thought of the above, he would have a reasonable chance of recovering most of the aircraft with their crews (one may have been shot down, one or two, may have gotten lost).

"What if" they did get bounced by a Zero? At least they had the means to somewhat defend themselves."

Compared to a "what if" they all run out of gas and crash. Only that was not a "what if", that was a "guarantee".

 

[MiTasol]

It is very clear that the manual figures are very conservative.

to allow for an "average" pilot on an "average" runway whereas the test results are more likely to be a highly experienced pilot operating off a concrete or blacktop runway

 

[MiTasol]

Well, if one checked an x number of pilot manuals and discovered that the data given in all of them is greatly in disagreement with data obtained from actual tests, it is quite logical to assume that the same applies to the B-25 manual as well. Second, it is clear that if the manual was absolutely correct, the Doolittle Raid would have never taken place as none of the B-25s taking part would have been able to take-off (yes, I have added the effect of the carrier's speed)! So what more do you need to prove the manual data wrong?

You forget that the Doolittle raid pilots spent weeks taking off from an airfield that had the operational deck length marked out and specifically developed a takeoff configuration that would allow them to fly that operation.

Instead of having the usual margins above stall they operated close to it, etc and they did not have to worry about any obstacles in front of them so could accelerate straight and level, or even mush down a little, from their almost stalled condition.

 

[FLYBOYJ]

On mission success, maybe, against satisfactory instrument approaches, no. The actual known probability of crashing all planes before approach, 100% (except one in Russia) thus, no instrument approaches.

I'm speaking in general terms - You flew a large 4 engine aircraft, would you think it was safe to shoot an ADF approach where only tones were guiding you in lieu of a needle and doing that approach alone without another set of eyes? Oh and at 19 years old? That what many Lancaster pilots were doing and I think it's safe to say that many of a crew that perished during these approaches might have lived had there been another set of trained eyes in the cockpit.

You are probably right however the assumption was wrong. Like Pearl Harbor, surprise was critical to mission success. Few air engagements were experienced.

But again, they didn't know what to expect so they prepared for the worse case

The added fuel would be good for an additional hour and half cruise, or about 240 miles, more than making up for the lost two hundred miles. The original mission took 13 hours. So the new mission would be 14 and half hours. I would bet that if Doolittle asked all his hand selected pilots if they could fly this mission, AND BOMB JAPAN, for 14.5 hours without a copilot, all would have said, "no, sweat". It would be a long and stressful mission with the initial part, flying low level, going to Japan, bombing Japan, is the hardest but also most pumped up with adrenalin. The last leg, going to China, uneventful and far less stressful, except watching the fuel gage, certainly would not be a problem with an autopilot (unknown if installed). But minor in any event. The navigational part of bombardier/navigator was definitely the most difficult and continuous effort and were specially trained. The bombardier part using the "Mark Twain" bomb aiming device, basically a protractor with a bar on it, would probably have taken about 10 minutes to be an expert.

That's an assumption - To say Doolittle was a smart man is an understatement, if he thought it would have helped the mission I'm sure he would have left the co-pilot behind

Doolittle was looking at the loss of 100% of the aircraft, all crew member spread out over the ocean or mainly Japanese held land and the possibility of most of the crews killed or captured. Fortunately and amazingly most of the crews came back, but he didn't know that at the time. If he had thought of the above, he would have a reasonable chance of recovering most of the aircraft with their crews (one may have been shot down, one or two, may have gotten lost).

Again an assumption

Compared to a "what if" they all run out of gas and crash. Only that was not a "what if", that was a "guarantee".

And again, I believe Doolittle planned this mission to have every resource available to him and his crews including an extra operator in the cockpit and someone to shoot a gun, regardless of the perceived outcome.

 

[special ed]

Don't forget, in China, Doolittle was despondent and expected court marshal as he lost all his aircraft. The original Roosevelt plan was to give the surviving B-25s to Chennault who had been lobbying for B-25s.

 

[Greg Boeser]

Poor Chennault. It seems he had really bad luck getting his hands on bombers. All the Doolittle ships were lost, and later the first B-25s which would form the 11th Bomb Squadron lost four of six enroute to China from India.

 

[Trilisser]

You forget that the Doolittle raid pilots spent weeks taking off from an airfield that had the operational deck length marked out and specifically developed a takeoff configuration that would allow them to fly that operation.

Instead of having the usual margins above stall they operated close to it, etc and they did not have to worry about any obstacles in front of them so could accelerate straight and level, or even mush down a little, from their almost stalled condition.

There is a report on B-26 take-off and landing and the report has several differing figures with explanations like "absolute minimum", "average" and so on. That report is on www.wwiiaircraftperformance.org. But no comparable report there on the B-25. And the report mentions what kind of runway was used. The B-25 pilot manual gives data for 3 different runways: hard surface runway, sod-turf and soft surface runway and 4 wind speeds.

 

[davparlr]

I'm speaking in general terms - You flew a large 4 engine aircraft, would you think it was safe to shoot an ADF approach where only tones were guiding you in lieu of a needle and doing that approach alone without another set of eyes? Oh and at 19 years old? That what many Lancaster pilots were doing and I think it's safe to say that many of a crew that perished during these approaches might have lived had there been another set of trained eyes in the cockpit.

But again, they didn't know what to expect so they prepared for the worse case

That's an assumption - To say Doolittle was a smart man is an understatement, if he thought it would have helped the mission I'm sure he would have left the co-pilot behind

Again an assumption

And again, I believe Doolittle planned this mission to have every resource available to him and his crews including an extra operator in the cockpit and someone to shoot a gun, regardless of the perceived outcome.

I would be surprised if the B-25s did not have the best ADF equipment available, especially since they apparently were transferred from anti-submarine work. I can't imagine anybody fling an approach with tones, I didn't know they did that. I did fly an A-N course in Canada once for fun. Didn't like it. If I remember correctly, I did fly an ADF approach into Addis Ababa, along with enroute navigation. I didn't think it was any more complex than a non-precision VOR approach. I also flew a FOUR ADF approach to an ILS final into Tehran, Iran. I needed a copilot and a navigator to handle that. Luckily we had four ADF heads, two for the pilots, two for the navigator, so we just switched between heads.

For approaches, the expert navs could have provide extra eyes in a better position to spot landmarks.

Hard to prepare for all running out of gas and crashing. I do suspect Doolittle thought about early departure, say Halsey chickened out wanted to turn around, which would have never happened. I would suspect Doolittle was prepared to launch even if they could only reach their targets. I also suspect he discussed this with his pilots, who probably mostly agreed.

An amazing amount of courage to climb into a plane knowing it did not have the fuel to land safely and knowing you could end up dead or possibly worse being captured and tortured. Heroes all!

 

[FLYBOYJ]

I would be surprised if the B-25s did not have the best ADF equipment available, especially since they apparently were transferred from anti-submarine work. I can't imagine anybody fling an approach with tones, I didn't know they did that. I did fly an A-N course in Canada once for fun. Didn't like it. If I remember correctly, I did fly an ADF approach into Addis Ababa, along with enroute navigation. I didn't think it was any more complex than a non-precision VOR approach. I also flew a FOUR ADF approach to an ILS final into Tehran, Iran. I needed a copilot and a navigator to handle that. Luckily we had four ADF heads, two for the pilots, two for the navigator, so we just switched between heads.

Those were the approaches of the day until more definitive precision approaches were developed (Localizer and eventually ILS)

For approaches, the expert navs could have provide extra eyes in a better position to spot landmarks.

All good until you have to make your decent in low visibility

Hard to prepare for all running out of gas and crashing. I do suspect Doolittle thought about early departure, say Halsey chickened out wanted to turn around, which would have never happened. I would suspect Doolittle was prepared to launch even if they could only reach their targets. I also suspect he discussed this with his pilots, who probably mostly agreed.

Agree

An amazing amount of courage to climb into a plane knowing it did not have the fuel to land safely and knowing you could end up dead or possibly worse being captured and tortured. Heroes all!

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