# B-29 Generator or Motor in tail part



## M. Tanaka (Oct 11, 2021)

Hi, does anyone recognize this, held by a local museum?
A part from downed B-29 42-65212 T-square 42, on April 7th, 1945, Chofu, Tokyo.
Looks like 'Putt-putt' generator, or, Central Firing System gun motor. 
Any input would be appreciated.
Regards, 
M. Tanaka


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## FLYBOYJ (Oct 11, 2021)

I believe it is an electrical component, probably part of the fire control system. This is what the B-29 APU (Putt-putt) looked like

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## M. Tanaka (Oct 11, 2021)

Many thanks. A motor that moves the gun vertically or horizontally like this you mean. 
Thanks again. mt

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## M. Tanaka (Oct 11, 2021)

Sorry, pictures from below link seems slightly different in its shape. No other possibility... mt
*B-29 Tail Azimuth and Elevation Motors





United States Boeing B-29A Super Fortress 44-62208 Miss Liberty Belle


United States Boeing B-29 Super Fortress Bomber Aircraft A.A.F. Serial Number B-29A-65-BN 44-62208 History of B-29A-65-BN 44-62208 Miss Liberty Belle Body, Installation - Tail ASSY 3-14335-13 UNIT 998.During World War Two the B-29 Super Fortress bombers were built by three different companies...



www.questmasters.us




*

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## M. Tanaka (Oct 15, 2021)

One more possibility; one of CFS amplidynes at the bank of firing commander seat?


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## EAIAnalog (Oct 18, 2021)

The B-29 was a mostly electric aircraft with a dollop of hydraulics. So there were a lot of motors, generators, and dc-ac converters. This isn't from an amplidyne because that was a special motor-generator on a single shaft. For the same reason, dc-ac converters can be ruled out. So we're left with motors and generators. The only stand-alone generators I know about are on the engines or on the putt-putt. This item looks too small to be any of those. So we're left with one of the many motors. On the left end is probably the brush assembly which clamps the brushes to the motor's commutator. It doesn't look like the brush assembly on the gun turret motors, so they are ruled out. Unfortunately I don't have any information on the autopilot servo motors, so this might be one of them. And there is a compressor motor on each gun turret. However, on all of the motors, the end cap and brush assembly is the same diameter as the motor casing. Here it is much smaller. I'm attaching an exploded view of the compressor motor from a maintenance document, just to illustrate what I mean.

It would be helpful if a good picture of the part were available, possibly from more than one angle. There are two protuberances from the middle of the part that are puzzling, and a better picture would help.

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## MiTasol (Oct 22, 2021)

I do not think it is a Cornelius compressor part but I would not rule it out as it is purely a gut feeling.

To me it looks like an electric motor that is missing the whole end containing the bearing and brushes. See below and consider that all the parts inside the red line are missing.





As others have said - better photos would help - as would any part numbers and stamps on the unit.

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## M. Tanaka (Oct 22, 2021)

Many thanks; yes, additional pictures are on the way as the local museum accepted my request; please give me a few more days.
Meanwhile, it that is the case, where the motor is located on the B-29? Or, is it too common one that cannot be decided which one?


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## MiTasol (Oct 22, 2021)

We can guess better when the additional photos arrive but from memory the B-29 used electric turrets so there will be two or more per turret. Flaps and landing gear are electric and probably the bomb doors as well. It is not an aircraft I have worked on much and not one I have any great interest in.

Boeing B-29 Erection and Maintenance Manual is a link to at least one manual.


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## Shinpachi (Oct 26, 2021)

Sorry but I happened to find these images at 8:03 in a Youtube video.
My instant impression as a former engineer, the motor/generator case would have been removed by an engineer to check inside structure.








Source: //www.youtube.com/watch?v=koKN5mqGMgk&t=482s

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## M. Tanaka (Oct 26, 2021)

Shinpachi-san,.
Thank you for reminding me of the video ! The part is exactly what I am trying to identify.
I have heard that the part was picked up from underground 1 meter below by the owner of the field, so not sure an engineer could examine it at that time. Let me check if there is any additional information.

Dear all,
The Museum of Flight, Seattle, has kindly come back with their view to the same question of mine; it is likely be the generator part of APU.
Anyway, some more pictures follow shortly; so let us see if it becomes clear.

With many thanks, mt


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## Shinpachi (Oct 26, 2021)

Thanks Tanaka-san.
As you may know well, there was a facility of IJA Special Intelligence Division (陸軍特別情報部) in Chofu as well as in Tanashi, Tokyo. I think that such a motor/generator would have been a good material for them to research.


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## M. Tanaka (Nov 1, 2021)

Taking time more than expected, but please wait for a while until the local museum responses with new pics.


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## MiTasol (Nov 2, 2021)

No panic.

Those of us who are most likely to respond will automatically get notification when you reply.

I for one would rather a long wait for quality photos than a quick and nasty photo or two

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## M. Tanaka (Nov 9, 2021)

Hi all,
Please find three pictures from the local museum with size information, though not clear enough, unfortunately.
Your further inputs would be highly appreciated.

(a bit earlier but deleted attached file due to the arrangement with the local museum.)

Regards,
M. Tanaka


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## MiTasol (Nov 9, 2021)

Please thank the person who provided the photos for those dimensions - they are very detailed and quite readable. I have saved then and adjusted the lighting to show more detail so I can do more research.


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## M. Tanaka (Nov 25, 2021)

Hi all,
As a possible conclusion. 
1) Dotted part of the left pic from FLYBOY above;
2) Red-circled part of the center pic from Museum of Flight in Seattle, but type maybe different;
3) Not-circled parts of the right pic from MiTasol above, probably except No.18 etc.;

All indicate to me 'generator of the put-put APU'. 
Is it acceptable for you all?

Your inputs would be appreciated.

Regards, mt

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## MiTasol (Nov 25, 2021)

That is most likely to be correct.
Congratulations on your research.

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## Shinpachi (Nov 25, 2021)

I think it is too early to conclude, Tanaka-san, because the motor/generator relic has no permanent magnets but coils on both armature and stator, which means the relic is not a generator but a motor. Wasn't it from either rudder servo or elevator servo of a B-29 as no one pointed it out yet? 
This is just my guess at the moment.


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## M. Tanaka (Nov 25, 2021)

Shimpachi-san,
Thank you as always.

For Autopilot Servo motors, it was actually mentioned by EAIAnalog above; so please let me ask if you have any further information on the shape or size, etc., as I have not reached that far. Happy to check this possibility going forward.

And, sorry to make such an ABC type question, but 'no permanent magnets but coils on both armature and stator means the relic is not a generator but a motor'. Isn't there 'no permanent magnetic' type generator'? If so, does it make difference? Please allow me to ask, lacking basic knowledge.

Any help would be highly appreciated.

Regards, mt


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## Shinpachi (Nov 25, 2021)

There are two types of electric motor - permanent magnet type and induction type.
The former can be used as generator but the latter not.
The relic in question is induction type.

I find no more details about the rudder/elevator servos but location and basic mechanism so far.
Need further research.






Source: Mechanism for the control surfaces of the B-29

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## MiTasol (Nov 25, 2021)

I could only find this photo of the B-29 servos - all are practically identical and there are no dimensions.
There are electric motors on all the turrets as well. Again no dimensions













Going by the conduit size these motors are quite large

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## Shinpachi (Nov 26, 2021)

I have been wondering how the two bolts which stuck out from the outer case were used as not seen in turret photos.
I might have found a clue with this diagram.

Motor: Air Associates Model EE-125M1/EE-1370
Size: Unknown




Source: Overhaul Instructions for Air Associates Electric Motors

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## Shinpachi (Nov 27, 2021)

Motor EE125M1
Overall Height 7.688 inches (19.52752cm)
Overall Length 7.812 inches (19.84248cm)
Overall Width 4.562 inches (11.58748cm)
Source: https://fsg-61-electric-power.parttarget.com/motors-electrical-EDD2198_EE163-2.html

Armature part seems to be still available as EE104M1 for replacement.




Source: PESCO EE125M1 ARMATURE W/BEARINGS EE104M1-1 *NEW* | eBay

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## Shinpachi (Nov 27, 2021)

Stator part as junk.
This kind of aero-motors seem to have been used for pumps in the hydraulic system if not used for servos.
This is my temporary conclusion at the moment. Thanks.









Source: PESCO BODY W/COIL PACK AND SHOES *SV* 3.75HP MOTOR | eBay

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## MiTasol (Nov 27, 2021)

Shinpachi said:


> I have been wondering how the two bolts which stuck out from the outer case were used as not seen in turret photos.
> I might have found a clue with this diagram.
> 
> Motor: Air Associates Model EE-125M1/EE-1370
> ...


You are right - they indicate a side mounting so that rules out turret motors and narrows it down considerably. As you say a hydraulic pump is likely as is a propeller feathering pump on aircraft with Ham Std props. A lot of aircraft of the time also carried similar fuel pumps but I do not know if the B-29 did.

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## Shinpachi (Nov 27, 2021)

Thank you very much for your kind comments, MiTasol.
I am just wondering how this tail skid was activated.





Source: B29 tail skid by roaklin on DeviantArt


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## M. Tanaka (Nov 28, 2021)

Shimpachi-san, MiTasol,

Thank you so much.
Am I correct to say at this stage; 
1) Not generator on APU, not servo motor in autopilot system, not tail gun turret motor;
2) It is considered that No.25 & 29 and the other some parts on the attached are the ones;
3) Likely be the one attached to hydraulic pump somewhere

And, if you elaborate 'propeller feathering pump on aircraft with Ham Std props', it would be greatly appreciated.
As it was found nearby tail part of the B-29, would like to check if it does not related to propeller related item. 

Regards, mt


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## MiTasol (Nov 28, 2021)

Thank you Shinpachi for the photo.
Electrically that tail skid is operated in accordance with the attached wiring diagram - it is in the lower right corner





I cannot see many tail skid components in this diagram





I think we can safely eliminate the tail skid motor as that is attached by an end flange rather than a saddle





The remaining options *to me* are feathering pumps (one per powerplant) and fuel transfer pumps (the B-29 has three at least).




I will try and measure my DC-3 Pesco feathering pump tomorrow but I have a very busy week so may not be able to.

I have no pictures of fuel transfer pumps unfortunately.

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## Shinpachi (Nov 28, 2021)

M. Tanaka said:


> Shimpachi-san, MiTasol,
> 
> Thank you so much.
> Am I correct to say at this stage;
> ...


I do not ensure the exact model number for the relic as there seemed several similar models but your summary is what I have suggested, Tanaka-san.
Thanks.


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## MiTasol (Nov 28, 2021)

The B-29 also has at least one electric hydraulic pump which is saddle mounted. The shape is considerably different to the feather pump so it should be easy to determine which is more applicable.

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## Shinpachi (Nov 28, 2021)

Getting back to the start line, I think this gentleman, Keiho Shimada, in the video I introduced with my post #10 could know more details.
He says he was working for an arsenal of present NTT in Chofu during the war to build submarine detectors.

The video does not tell more details but, in my impression as a postwar kid to watch it, some parts of the crashed B-29 would have been sent to his arsenal to research and he may have brought it back to his home as a war souvenir after the war was over like many Japanese people did at the time. If so, he would have been obliged to bury it in the backyard immediately being afraid of the interrogation by GHQ but finally dug it up decades later to donate it to the local museum. This depends on how the relic came to the museum.

Mr. Keiho Shimada





Original video

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## M. Tanaka (Dec 3, 2021)

Shimpachi-san,
Thank you; I am trying to get contact information of Mr. Shimada, though not sure if I could communicate with him as he should be now 92.
Further information may follow.
---
Anyway, if my understanding is correct; it would be No.25+29 of the below breakdown chart, consisting of the inner/outer parts as the two photos below. Unlikely a hydraulic pump considering two amounts, but one of the generic motor such as propeller feathering pumps (one per powerplant) or fuel transfer pumps (the B-29 has three at least).

Then, just to double-confirm where possibly it was;
- 'propeller feathering pump' is for propeller pitch control, located in each engine
- 'fuel transfer pump' is for the transfer among bomb-bay and wing tanks, e.g. 'G' below, but 'H' Fuel Booster Pump maybe similar. (chart is from page 114 of 'Owner's Workshop Manual' attached below)

Can we conclude like this? It looks not from tail part of the B-29, but it could happen after mid-air collision and crash after that.


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## MiTasol (Dec 3, 2021)

My apologies for the slow reply - too busy
Attached are photos of my Pesco Feathering pump as fitted to C-47 and many other aircraft. My apologies for it being dirty but I did not have time to clean it
As you can see it is a Pesco type 280-2C and totally different from the Pesco 1E-620 shown in the drawing from the B-29 manual. It is however apparently the same construction as the motor M. Tanaka is investigating but it is a smaller unit being just 11cm diameter.


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## Shinpachi (Dec 4, 2021)

My hat off to the great efforts for research, Tanaka-san, and tons of precious technical data, MiTasol.
My first impression to see the relic pictures was that someone could have buried it carefully wrapping with oil paper or putting it in a box as I found no trace of soils between the armature and the stator.


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## Shinpachi (Dec 4, 2021)

The fuel transfer pump looks an explosion proof type or a sealed type as its role is sensitive. The booster pump would be same in its role.
This is my quick research for them but the right answer for your question, Tanaka-san, will be the electric motor for the propeller feathering pump as MiTasol has indicated.





Source: Overhaul Instructions for Fuel and Water Pumps


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## Shinpachi (Dec 4, 2021)

The motor for the booster pump looks a sealed type.





Source: Overhaul Instructions for Refueling & Booster Pumps


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## Shinpachi (Dec 4, 2021)

Mr. Shimada's testimony part from 7:43 to 8:39 in the video.

Narration: Keiho Shimada 84. When the B-29 crashed (on April 7, 1945), he was an engineer of Ministry of Communication (present NTT). No sooner he heard the news than he hurried to the crash site.

Shimada: My job was to build submarine detectors for aircraft. I thought the equipment onboard the B-29 would be so excellent I went there to bring them back for research. I saw a torn off part of the fuselage (tail part). It looked almost 2 meters high or higher. As the area was blocked by the military police, I was unable to get any closer.

Narration: All the wreck of the B-29 crashed in Chofu district were preserved and recovered by the military police shortly. A bomb dropped in the Kokuryo block was not recovered and had been left there as it was ( till 2008. This is the main theme of this video).

What Shimada saw





How the airframe scattered (unexploded bomb in the center)





Recovered 2000lb bomb in 2008





How the B29 was attacked

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## M. Tanaka (Dec 4, 2021)

Shimpachi-san,

Thank you always. 
Actually, Iwasaki-san, another old man on the video, is the man who has directly asked me for the research. 
I am keeping updated him of any developments here.

If I add Iwasaki-san's comment; 
- The parts was found in a farm, nearby the tail part was fallen
- It was not taken away by military police after the crash, but left underground until the farm owner found it in his work a few years later
- Iwasaki-san received it from the farmer who decided to dispose it 5 - 10 years back from now, when it was donated to the museum
Not yet successfully contacted to Mr. Shimada, but he did not come close enough to B-29, as he told in the video.

If we come to a fair conclusion and ready to make an explanation text draft for the museum, which I will share, I would like to add your nicknames, Shimpachi-san, MiTasol. Please allow me. 

Best regards,
M. Tanaka

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## MiTasol (Dec 5, 2021)

Good day M Tanaka
Generally speaking I do not seek recognition for any help I give however I have no strong objection to being named. I will leave the decision to you.
Mi Tasol


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## Shinpachi (Dec 5, 2021)

I appreciate your courtesy, Tanaka-san. 
I have enjoyed my own research this time.
Thank you very much and let me wish your good luck.


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## M. Tanaka (Dec 16, 2021)

Hi, here attached is my summary to be submitted to the local museum, for your review.
If anything critical, would be appreciated if you let me know.
Many thanks, mt

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## Shinpachi (Dec 16, 2021)

If I were you, Tanaka-san, I would summarize like follows though I do not deny your good job. No problem but technical explanation looks a little weak when questioned by a technical expert.

Main points to identify the relic.
1. It is not a generator but a motor because of its structure.
2. There are two bolts on the relic to fix the motor to the base.

Therefore, it is neither APU generator nor a motor for the turrets.
It is a motor for the hydraulic system as the design and purpose coincides to EE125M1 well as example.
No such motors are found in the B-29 except the motor for the propeller feathering pump.
Therefore it is natural to think that the relic is a motor for the propeller feathering pump.

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## M. Tanaka (Dec 16, 2021)

Shinpachi-san,
Thank you always. I am quite flexible on this so added suggested texts in the explanation section as attached.
Will go report to the local museum next week.

Best regards,
M. Tanaka

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## Shinpachi (Dec 16, 2021)

Good job again, Tanaka-san


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