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How could the B-29 bomber back up under its own power?

Why don't planes have a reverse propeller as air brakes?Will an aircraft always crash on take-off if de-icing is not performed correctly?How does Chicago O'Hare's tower sequence aircraft at peak capacity?What item is a pushback operator holding up after pushback?What is the power rating of the ground power unit for Bombardier Dash 8 Q400?Is the Auxiliary Power Unit used after landing when ground power is available?Drop the rope or drag the rope?How do tugs push back the Antonov 225?Why must some aircraft get permission to start their engines?What is the speed during push-back?During single-engine taxi, how is the asymmetric power compensated for?

26

$begingroup$

I was watching some footage of the Enola gay

I was interested in the part where the plane was backing up over the bomb (starts around 18:27). It appears to be doing this under its own power with the propellers running. Could the B-29 reverse some propellers to do this?

ground-operations b-29

share|improve this question

edited May 17 at 16:33

ymb1

72.4k7234388

asked May 17 at 15:28

MachavityMachavity

2,77521538

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  aviation.stackexchange.com/questions/7689/…
  $endgroup$
  – BowlOfRed
  May 17 at 16:16
  

  
  
  
  


• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  $begingroup$
  @BowlOfRed: Having checked two B-29 declassified manuals, neither mention reversible pitch props, only that they are full-feathering.
  $endgroup$
  – ymb1
  May 17 at 16:34
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  @ymb1 Check out Mike's answer. He actually found a video with the props shown reverse pitching, along with landings done using only reversible props. I'm guessing it was to facilitate them landing on those shorter south Pacific SeaBee runways
  $endgroup$
  – Machavity
  May 17 at 18:48
  

  
  
  
  


• 
  
  
  

  
  5
  

  
  
  
  
  
  

  
  $begingroup$
  @Machavity: Nice. And here's a bit of trivia, the B-29 development cost more than the Manhattan Project.
  $endgroup$
  – ymb1
  May 17 at 23:31
  

  
  
  
  


• 
  
  
  

  
  5
  

  
  
  
  
  
  

  
  $begingroup$
  @ymb1: Most B-29s didn't have reversible-pitch propellers. The Silverplate B-29s (the nuclear-weapon-delivery version), however, did.
  $endgroup$
  – Sean
  May 19 at 0:25
  

  
  
  
  

add a comment | 

26

$begingroup$

I was watching some footage of the Enola gay

I was interested in the part where the plane was backing up over the bomb (starts around 18:27). It appears to be doing this under its own power with the propellers running. Could the B-29 reverse some propellers to do this?

ground-operations b-29

share|improve this question

edited May 17 at 16:33

ymb1

72.4k7234388

asked May 17 at 15:28

MachavityMachavity

2,77521538

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  aviation.stackexchange.com/questions/7689/…
  $endgroup$
  – BowlOfRed
  May 17 at 16:16
  

  
  
  
  


• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  $begingroup$
  @BowlOfRed: Having checked two B-29 declassified manuals, neither mention reversible pitch props, only that they are full-feathering.
  $endgroup$
  – ymb1
  May 17 at 16:34
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  @ymb1 Check out Mike's answer. He actually found a video with the props shown reverse pitching, along with landings done using only reversible props. I'm guessing it was to facilitate them landing on those shorter south Pacific SeaBee runways
  $endgroup$
  – Machavity
  May 17 at 18:48
  

  
  
  
  


• 
  
  
  

  
  5
  

  
  
  
  
  
  

  
  $begingroup$
  @Machavity: Nice. And here's a bit of trivia, the B-29 development cost more than the Manhattan Project.
  $endgroup$
  – ymb1
  May 17 at 23:31
  

  
  
  
  


• 
  
  
  

  
  5
  

  
  
  
  
  
  

  
  $begingroup$
  @ymb1: Most B-29s didn't have reversible-pitch propellers. The Silverplate B-29s (the nuclear-weapon-delivery version), however, did.
  $endgroup$
  – Sean
  May 19 at 0:25
  

  
  
  
  

add a comment | 

$begingroup$

I was watching some footage of the Enola gay

I was interested in the part where the plane was backing up over the bomb (starts around 18:27). It appears to be doing this under its own power with the propellers running. Could the B-29 reverse some propellers to do this?

ground-operations b-29

share|improve this question

edited May 17 at 16:33

ymb1

72.4k7234388

asked May 17 at 15:28

MachavityMachavity

2,77521538

$endgroup$

share|improve this question

edited May 17 at 16:33

ymb1

72.4k7234388

asked May 17 at 15:28

MachavityMachavity

2,77521538

share|improve this question

edited May 17 at 16:33

ymb1

72.4k7234388

asked May 17 at 15:28

MachavityMachavity

2,77521538

edited May 17 at 16:33

ymb1

72.4k7234388

edited May 17 at 16:33

ymb1

72.4k7234388

asked May 17 at 15:28

MachavityMachavity

2,77521538

asked May 17 at 15:28

MachavityMachavity

2,77521538

3 Answers
3

active

oldest

votes

39

$begingroup$

Some B-29s had reversible pitch propellers. All the B-29s used for the Atomic bomb missions had reversible pitch propellers.

Wikipedia B-29 Variants

Moreover, engine packages changed; including the type of propellers and range of the variable pitch. A notable example were the eventual 65 airframes (up to 1947's end) for the Silverplate and successor-name "Saddletree" specifications; built for the Manhattan Project with Curtiss Electric reversible pitch propellers.

Army Air Forces tests reversible propellers for B-29 bomber

share|improve this answer

edited May 17 at 18:33

Machavity

2,77521538

answered May 17 at 18:17

Mike SowsunMike Sowsun

21.5k26989

$endgroup$

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  $begingroup$
  There ya go... I guess I skimmed the wiki article too quickly.
  $endgroup$
  – John K
  May 17 at 19:09
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  What is the logic behind requiring reversible pitch propellers for the Manhattan project?
  $endgroup$
  – ROIMaison
  2 days ago
  

  
  
  
  

add a comment | 

17

$begingroup$

Although I can't find direct hard documentary evidence, I'll make the case that that B-29 has Curtis Electric reversing propellers thusly:

1. We know that Curtis had a reversing version of its electric propeller during WWII because the Consolidated had them for the inboard engines of the Coronado flying boat.


2. The B-29 in the video is clearly backing up under its own power, and you can tell at least two engines are higher RPM from the blade strobing. It's not the wind blowing it back. The B-29 had a free castering unsteerable nose wheel and you can see that steering is being done by ground crew manhandling a towbar for fine steering, probably assisted (or hindered) by bits of braking by the pilot. Looks like a pretty tricky task.


3. There were many field mods done on the B-29 and things like installing reversing props in the field as an upgrade would certainly have been done late in the war. And you can bet that Enola Gay had all of the latest and greatest field mods. As field mods they were probably covered by Flight Manual Supplements and that sort of documentation can be very hard to track down.

share|improve this answer

edited May 17 at 17:38

answered May 17 at 17:07

John KJohn K

29.3k14692

$endgroup$

• 
  
  
  

  
  4
  

  
  
  
  
  
  

  
  $begingroup$
  I suspect that your answer is basically correct except that the steering is being caused not by the pilot braking but rather by the people that we see in front of the nose from 18:40-18:47 pushing sideways on a towbar attached to the nosewheel to cause the nosewheel to castor. The tail might rise and fall more if the pilot were actually braking.
  $endgroup$
  – quiet flyer
  May 17 at 17:18
  
  

  
  
  
  


• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  $begingroup$
  Very good observation @quietflyer thanks. I've revised my post.
  $endgroup$
  – John K
  May 17 at 17:39
  

  
  
  
  

add a comment | 

2

$begingroup$

Many planes have props that can be set to a negative angle, for braking during landing. So, that could also be used to reverse under its own power.

share|improve this answer

edited May 19 at 0:27

Sean

6,93243391

answered May 17 at 16:42

pnautapnauta

593

$endgroup$

• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  $begingroup$
  (its it is)
  $endgroup$
  – Peter Mortensen
  May 18 at 19:16
  

  
  
  
  


• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  $begingroup$
  @PeterMortensen just click edit :)
  $endgroup$
  – Robert Grant
  2 days ago
  

  
  
  
  

add a comment | 

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39

$begingroup$

Some B-29s had reversible pitch propellers. All the B-29s used for the Atomic bomb missions had reversible pitch propellers.

Wikipedia B-29 Variants

Moreover, engine packages changed; including the type of propellers and range of the variable pitch. A notable example were the eventual 65 airframes (up to 1947's end) for the Silverplate and successor-name "Saddletree" specifications; built for the Manhattan Project with Curtiss Electric reversible pitch propellers.

Army Air Forces tests reversible propellers for B-29 bomber

share|improve this answer

edited May 17 at 18:33

Machavity

2,77521538

answered May 17 at 18:17

Mike SowsunMike Sowsun

21.5k26989

$endgroup$

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  $begingroup$
  There ya go... I guess I skimmed the wiki article too quickly.
  $endgroup$
  – John K
  May 17 at 19:09
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  What is the logic behind requiring reversible pitch propellers for the Manhattan project?
  $endgroup$
  – ROIMaison
  2 days ago
  

  
  
  
  

add a comment | 

39

$begingroup$

Some B-29s had reversible pitch propellers. All the B-29s used for the Atomic bomb missions had reversible pitch propellers.

Wikipedia B-29 Variants

Moreover, engine packages changed; including the type of propellers and range of the variable pitch. A notable example were the eventual 65 airframes (up to 1947's end) for the Silverplate and successor-name "Saddletree" specifications; built for the Manhattan Project with Curtiss Electric reversible pitch propellers.

Army Air Forces tests reversible propellers for B-29 bomber

share|improve this answer

edited May 17 at 18:33

Machavity

2,77521538

answered May 17 at 18:17

Mike SowsunMike Sowsun

21.5k26989

$endgroup$

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  $begingroup$
  There ya go... I guess I skimmed the wiki article too quickly.
  $endgroup$
  – John K
  May 17 at 19:09
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  What is the logic behind requiring reversible pitch propellers for the Manhattan project?
  $endgroup$
  – ROIMaison
  2 days ago
  

  
  
  
  

add a comment | 

$begingroup$

Some B-29s had reversible pitch propellers. All the B-29s used for the Atomic bomb missions had reversible pitch propellers.

Wikipedia B-29 Variants

Moreover, engine packages changed; including the type of propellers and range of the variable pitch. A notable example were the eventual 65 airframes (up to 1947's end) for the Silverplate and successor-name "Saddletree" specifications; built for the Manhattan Project with Curtiss Electric reversible pitch propellers.

Army Air Forces tests reversible propellers for B-29 bomber

share|improve this answer

edited May 17 at 18:33

Machavity

2,77521538

answered May 17 at 18:17

Mike SowsunMike Sowsun

21.5k26989

$endgroup$

share|improve this answer

edited May 17 at 18:33

Machavity

2,77521538

answered May 17 at 18:17

Mike SowsunMike Sowsun

21.5k26989

edited May 17 at 18:33

Machavity

2,77521538

edited May 17 at 18:33

Machavity

2,77521538

answered May 17 at 18:17

Mike SowsunMike Sowsun

21.5k26989

answered May 17 at 18:17

Mike SowsunMike Sowsun

21.5k26989

17

$begingroup$

Although I can't find direct hard documentary evidence, I'll make the case that that B-29 has Curtis Electric reversing propellers thusly:

1. We know that Curtis had a reversing version of its electric propeller during WWII because the Consolidated had them for the inboard engines of the Coronado flying boat.


2. The B-29 in the video is clearly backing up under its own power, and you can tell at least two engines are higher RPM from the blade strobing. It's not the wind blowing it back. The B-29 had a free castering unsteerable nose wheel and you can see that steering is being done by ground crew manhandling a towbar for fine steering, probably assisted (or hindered) by bits of braking by the pilot. Looks like a pretty tricky task.


3. There were many field mods done on the B-29 and things like installing reversing props in the field as an upgrade would certainly have been done late in the war. And you can bet that Enola Gay had all of the latest and greatest field mods. As field mods they were probably covered by Flight Manual Supplements and that sort of documentation can be very hard to track down.

share|improve this answer

edited May 17 at 17:38

answered May 17 at 17:07

John KJohn K

29.3k14692

$endgroup$

• 
  
  
  

  
  4
  

  
  
  
  
  
  

  
  $begingroup$
  I suspect that your answer is basically correct except that the steering is being caused not by the pilot braking but rather by the people that we see in front of the nose from 18:40-18:47 pushing sideways on a towbar attached to the nosewheel to cause the nosewheel to castor. The tail might rise and fall more if the pilot were actually braking.
  $endgroup$
  – quiet flyer
  May 17 at 17:18
  
  

  
  
  
  


• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  $begingroup$
  Very good observation @quietflyer thanks. I've revised my post.
  $endgroup$
  – John K
  May 17 at 17:39
  

  
  
  
  

add a comment | 

17

$begingroup$

Although I can't find direct hard documentary evidence, I'll make the case that that B-29 has Curtis Electric reversing propellers thusly:

1. We know that Curtis had a reversing version of its electric propeller during WWII because the Consolidated had them for the inboard engines of the Coronado flying boat.


2. The B-29 in the video is clearly backing up under its own power, and you can tell at least two engines are higher RPM from the blade strobing. It's not the wind blowing it back. The B-29 had a free castering unsteerable nose wheel and you can see that steering is being done by ground crew manhandling a towbar for fine steering, probably assisted (or hindered) by bits of braking by the pilot. Looks like a pretty tricky task.


3. There were many field mods done on the B-29 and things like installing reversing props in the field as an upgrade would certainly have been done late in the war. And you can bet that Enola Gay had all of the latest and greatest field mods. As field mods they were probably covered by Flight Manual Supplements and that sort of documentation can be very hard to track down.

share|improve this answer

edited May 17 at 17:38

answered May 17 at 17:07

John KJohn K

29.3k14692

$endgroup$

• 
  
  
  

  
  4
  

  
  
  
  
  
  

  
  $begingroup$
  I suspect that your answer is basically correct except that the steering is being caused not by the pilot braking but rather by the people that we see in front of the nose from 18:40-18:47 pushing sideways on a towbar attached to the nosewheel to cause the nosewheel to castor. The tail might rise and fall more if the pilot were actually braking.
  $endgroup$
  – quiet flyer
  May 17 at 17:18
  
  

  
  
  
  


• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  $begingroup$
  Very good observation @quietflyer thanks. I've revised my post.
  $endgroup$
  – John K
  May 17 at 17:39
  

  
  
  
  

add a comment | 

$begingroup$

Although I can't find direct hard documentary evidence, I'll make the case that that B-29 has Curtis Electric reversing propellers thusly:

1. We know that Curtis had a reversing version of its electric propeller during WWII because the Consolidated had them for the inboard engines of the Coronado flying boat.


2. The B-29 in the video is clearly backing up under its own power, and you can tell at least two engines are higher RPM from the blade strobing. It's not the wind blowing it back. The B-29 had a free castering unsteerable nose wheel and you can see that steering is being done by ground crew manhandling a towbar for fine steering, probably assisted (or hindered) by bits of braking by the pilot. Looks like a pretty tricky task.


3. There were many field mods done on the B-29 and things like installing reversing props in the field as an upgrade would certainly have been done late in the war. And you can bet that Enola Gay had all of the latest and greatest field mods. As field mods they were probably covered by Flight Manual Supplements and that sort of documentation can be very hard to track down.

share|improve this answer

edited May 17 at 17:38

answered May 17 at 17:07

John KJohn K

29.3k14692

$endgroup$

share|improve this answer

edited May 17 at 17:38

answered May 17 at 17:07

John KJohn K

29.3k14692

answered May 17 at 17:07

John KJohn K

29.3k14692

answered May 17 at 17:07

John KJohn K

29.3k14692

2

$begingroup$

Many planes have props that can be set to a negative angle, for braking during landing. So, that could also be used to reverse under its own power.

share|improve this answer

edited May 19 at 0:27

Sean

6,93243391

answered May 17 at 16:42

pnautapnauta

593

$endgroup$

• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  $begingroup$
  (its it is)
  $endgroup$
  – Peter Mortensen
  May 18 at 19:16
  

  
  
  
  


• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  $begingroup$
  @PeterMortensen just click edit :)
  $endgroup$
  – Robert Grant
  2 days ago
  

  
  
  
  

add a comment | 

2

$begingroup$

Many planes have props that can be set to a negative angle, for braking during landing. So, that could also be used to reverse under its own power.

share|improve this answer

edited May 19 at 0:27

Sean

6,93243391

answered May 17 at 16:42

pnautapnauta

593

$endgroup$

• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  $begingroup$
  (its it is)
  $endgroup$
  – Peter Mortensen
  May 18 at 19:16
  

  
  
  
  


• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  $begingroup$
  @PeterMortensen just click edit :)
  $endgroup$
  – Robert Grant
  2 days ago
  

  
  
  
  

add a comment | 

$begingroup$

Many planes have props that can be set to a negative angle, for braking during landing. So, that could also be used to reverse under its own power.

share|improve this answer

edited May 19 at 0:27

Sean

6,93243391

answered May 17 at 16:42

pnautapnauta

593

$endgroup$

share|improve this answer

edited May 19 at 0:27

Sean

6,93243391

answered May 17 at 16:42

pnautapnauta

593

edited May 19 at 0:27

Sean

6,93243391

edited May 19 at 0:27

Sean

6,93243391

answered May 17 at 16:42

pnautapnauta

593

answered May 17 at 16:42

pnautapnauta

593