Warbird Information Exchange

The gun diagrams bring up a question. I know B-25's were used for low level work in the Pacific, but I thought most B-26's went to Europe later in the war and were used in a medium level role. Have I missed an important part of history where B-26's utilized the fixed guns in low level operations?

I don't personally know too much about B-26 operations, the technical side is more my area. However, Greg Boeser over on ww2aircraft has a great thread discussing Marauder armament, operations and field modifications: https://ww2aircraft.net/forum/threads/b-26-marauder-weapons-thread.45567/

Hey everyone, here's n update that I had posted over on the original thread over on ww2 aircraft:

I'm in the process of purchasing microfilm blueprints for the B-26, but COVID has made doing so impossible for the time being. In the meantime, I have stumbled upon another conundrum: The mounting angle for the horizontal stabilizer.

B-26, B-26A, B-26B:
My most accurate set of blueprints (Drawing 5K-17988 or maybe SK-17988) lists no incidence value for the stabilizer, but shows the following:

I do not know where the angle is being measured from or what it's measuring. It's also not clear if it's inches or degrees, or if there's a missing decimal point. The E&M manual states that the incidence is 0 degrees, presumably measured from the Thrust Line, as the wing incidence (3.5 degrees) is measured from the thrust line. The POH makes no reference to incidence angles.

B-26B-1, B-26C, B-26F, B-26G:
The blueprints for the B-26B-1 do not list an incidence value for the stabilizer, but again have values that might be a reference to it.

I have no idea what the 1/2 and 1 1/2 values are in reference to, or what unit they are in. My guess would be that 1/2 is an angle (blueprint shows wing incidence as 3 1/2), but I have no theories regarding 1 1/2. The E&M manual for the B-1 & C models lists the stabilizer incidence as -0.5 degrees, again presumably in reference to the thrust line. Could this be what the 1/2 is referring to? It doesn't seem connected to the stabilizer's reference line/reference plane. The POH for these models lists the incidence as -5 degrees, which I assume is a typo from -0.5, but cannot verify. I don't have detailed blueprints for the F & G models or the E&M manual (not sure if it exists either), but the POH for said model makes no mention of incidence angles other that "wing incidence was increased by 3.5 degrees".

So I currently do not know the incidence angles for the horizontal stabilizers of any B-26 models. This won't be a very big deal once I have the proper diagrams, so I'm not overly concerned. The amount of time I can put towards this project should increase very soon as I'm currently taking a rather intensive online class for university, which ends in around two weeks. Will also be able to work more during the fall, as circumstances make attending classes during said period impossible. Will update y'all again when I have more info on the plane and/or have access to the diagrams. The last time I bought blueprints from the Smithsonian I had to agree not to make said blueprints available to the public and I expect it to be the same with this set, so unfortunately I will not be posting any of the diagrams when I do receive them.

Cheers,
-Matt

Hi all, here's an update for August:
I'm still trying to sort out how purchasing microfilm will work, but I do have a fairly good idea of what rolls I need for now and will purchase others depending on necessity. My latest effort has been to try to make an accurate database of B-26 production, and of the different models. This is still WIP, but I have been using 3 different sources: The Martin Marauder B-26 by Victor C. Tannehill (as quoted in [url='http://www.joebaugher.com/usaf_bombers/b26.html']Joe Baugher[/url]'s and the [url='http://320thbg.org/b-26_models.html']320thbg[/url]'s websites, I do not own the book), [url='https://www.asisbiz.com/B-26-Marauder.html']a database of serial numbers[/url] and [url='https://www.mdairmuseum.org/archival-collection']a list of all Martin produced aircraft[/url], courtesy of the Glenn L. Martin museum. They seem to agree on most numbers, but disagree on others.

All sources seem to agree that 5,266 B-26 aircraft were built by Martin, regardless of configuration.
-Tannehill describes the aircraft as originally produced, what the characteristics of the model were (sometimes incorrectly but most of the time accurately), and what they were converted into if conversions took place.
-The serial number database lists the aircraft's configurations as ordered/built. As such, it makes no mention of the B-26B-1, B-26C-6, XB-26D, XB-26E, AT-23A, TB-26G-15, TB-26G-25, JM-1 or JM-2.
-The Martin list reflects the final configuration of aircraft within the USAAC/USAAF, not what they were built as. It does not mention the JM-1 or JM-2.

In this post I will be using the shortened form "B-26(X)" to refer to all production blocks of that model, and will add the "-MA" suffix when talking about production blocks that have no numbers. In reality, all of these would have the "-MA" suffix or "-MO" (except the conversions, since they were not "produced") but I find that would make reading this tedious. In this text, "B-26A" represents both B-26A-MAs and B-26A-1s.

In most cases the number of aircraft converted from one configuration to another match up perfectly (Serial database + conversions according to Tannehill = Martin list), but there are notable discrepancies. Here is my breakdown of B-26 production according to those 3 sources:

All sources agree 201 B-26-MAs were built.

Tannehill and the Martin list both state that 109 of the 139 B-26As produced were B-26A-1-MAs, while the serial database claims 116 were. This discrepancy comes down to the last 7 B-26As produced, serials 41-7477 to 41-7483, which Tannehill & Martin claim were B-26As, while the database claims they were B-26A-1s. The only difference between the two types are the engines. This is the only time the serial number database contradicts the Martin list.

Tannehill claims that 307 B-26B-MA aircraft were built, of which 207 were converted into B-26B-1s and 100 remained as B-26B-MAs. The Martin list says there were 225 B-26B-1s and 81 B-26B-MAs, bringing the total to 306. The serial list claims 307 B-26B-MAs were built, but as previously stated does not provide any information about conversions.

Tannehill & the serial database state that there were 95 B-26B-2 aircraft were built, while the Martin list claims there were 96. To me, this suggests that one B-26B-MA was converted into a B-26B-2 as it would account for the missing B-26B-MA, but this is pure speculation.

All sources agree on the production of B-26B-3s to B-26B-35s, though Tannehill's descriptions range from accurate (various small things, but also explicit mention of the main wheels being enlarged from 47" diameter to 50", which was a theory I had) to an incorrect assessment (claiming the nose gear strut was lengthened by 6 inches instead of the trunnion being moved lower and forwards) to "I have no idea where he got this from" (claiming the B-26C-5 had landing gear doors with 3 sections, of which only one remained open when the gear was extended. Maybe he was reading into the B-25 at the time and confused the two? I do not know).

The Martin list states there were 101 B-26B-40 aircraft, 91 B-26B-45s and 208 AT-23As. The serial database lists 200 of each were built and no AT-23As, which would indicate 99 B-26B-40s and 109 B-26B-45s were converted into AT-23As. Tannehill agrees that 109 B-26B-45s were converted, but claims 141 B-26B-40s were converted into AT-23As, leading to a total of 250 AT-23As, 42 more than the Martin list. My excel spreadsheet describes only 139 when talking about Tannehill, as two of the 141 listed were later converted into XB-26Es.

The serial database states 175 B-26C-5 aircraft were built. The Martin list states there were 115 B-26C-5s and 60 B-26C-6s. The B-26C-6 was a conversion of the B-26C-5 that removed the co-pilot's position as well as some radio equipment. Naturally, the 60 B-26C-6s were converted from (and later converted back to) B-26C-5s. Tannehill confirms this, but claims only 59 were converted. I did not know what to make of this, but Joe Baugher's website has the answer (also quoted on the thread [url='https://ww2aircraft.net/forum/threads/martin-b26-marauder.42565/page-2#post-1514259']Martin B-26 Marauder[/url]):

My guess would be that Tannehill did not consider this aircraft a B-26C-6, since it's technically an XB-26E. We'll get into the ball of confusion that is the XB-26E in a bit, but first we'll finish up the B-26Cs

All sources agree on the production of B-26C-10 and B-26C-15 aircraft.

From B-26C-20 to B-26C-35 Tannehill and the Martin list/serial database agree on production, but disagree wildly about the number of aircraft converted to the AT-23B configuration:
B-26C-20s converted to AT-23Bs: 1 according to Tannehill, 0 according to Martin
B-26C-25s converted to AT-23Bs: 3 according to Tannehill, 1 according to Martin
B-26C-30s converted to AT-23Bs: 48 according to Tannehill, 23 according to Martin
B-26C-35s converted to AT-23Bs: 23 according to Tannehill, 200 according to Martin

All sources agree on production of B-26C-40s and on how many were converted into AT-23Bs.

The B-26C-45 is the weirdest one to me. The Martin list suggests that 25 of the 359 built were converted into AT-23Bs, and based on the total number of AT-23Bs listed, that a further 26 were built as AT-23Bs. The serial database supports the latter and cannot verify the former. Tannehill states that the last 26 B-26C-45s were built as AT-23Bs, which would mean all sources agree, BUT the serial numbers do not match up. The serial database lists the AT-23Bs as being aircraft 42-107471 to 42-107496, while Tannehill claims they were aircraft 42-95629 to 42-95737. Neither of these sets correspond to B-26C-45 serial numbers, so I'm not sure how to verify this.

The XB-26D was B-26-MA 40-1380, modified to test heated-surface deicing equipment.

The XB-26Es are very interesting and were hard to find information on. Joe Baugher was my only source on this for a while, but I believe I now have a full picture. The Martin list mentions 3 aircraft converted to this standard. Tannehill makes no claims about it and the serial number database has no reason to, as the XB-26Es were not conventionally ordered/produced.

For some reason, Martin used the "XB-26E" designation to refer to multiple aircraft. A post by[url='https://www.whatifmodellers.com/index.php?PHPSESSID=cfuk1m1s8jg3f37s3g03trl6gc&topic=41460.msg709827#msg709827']joncarrfarrelly on whatifmodellers[/url] explains the situation best:

41-34680 is listed as a B-26C-6 in the Martin list, explaining why it only mentions 3 XB-26Es instead of 4. It was indeed modified to B-26C-6 standard before being modified to this configuration, serving as the prototype for the B-26C-6 series. In his assessment of the XB-26E, [url='http://www.joebaugher.com/usaf_bombers/b26_10.html']Baugher mixes up 42-33190 and 41-31672[/url], claiming they are one and the same, and that there is some other "bomber version" he does not know the serial number of. In reality, 42-43319 is that bomber version, and it does have a name: Wild Willie II. Here are some pictures of some of the XB-26Es:



I find the XB-26Es very interesting, and wonder how they would perform in combat. I do not have performance figures on them. The extended nacelles look quite good in my opinion and make the aircraft look like the North American XB-28. The horn-balanced rudder, easily visible in the pictures, is also a very interesting modification.

All sources agree on B-26F and B-26G production as well as how many of them were converted into TB-26s and AT-23s.

None of the sources mention the JM-1 or JM-2 as they were all AT-23Bs and TB-26Gs given to the USN with little modification. Joe Baugher's breakdown is accurate as far as I can tell.

I hope y'all have found this informative,
-Matt

I do find it informative Matt. Thank you.

_________________
Better is the enemy of Good.

Thanks, Adam, glad to hear it. I have another small update today. While I haven't been able to do any work on the Marauder and am still waiting on some books, I did take a look at what patents on google were attributed to the Glenn L. Martin Company between 1937-1946 looking for some B-26 related ones. I found a few that I think fit that criteria, most interesting of which is a patent for an early form of the nose landing gear: https://patents.google.com/patent/US2222683A/en?assignee=glenn+l+martin+co&before=priority:19470101&after=priority:19360101&sort=old&page=4
https://ww2aircraft.net/forum/attachments/nose-landing-gear-patent-1-png.594808/
https://ww2aircraft.net/forum/attachments/nose-landing-gear-patent-2-png.594809/
https://ww2aircraft.net/forum/attachments/nose-landing-gear-patent-3-png.594810/
https://ww2aircraft.net/forum/attachments/nose-landing-gear-patent-4-png.594811/
https://ww2aircraft.net/forum/attachments/nose-landing-gear-patent-5-png.594812/

Main changes before production seem to be that the scissors were rotated 90 degrees around the strut and mounted around the bottom part of the strut instead of above it, and the landing gear doors and bay were simplified.

That's all I have at this time,
-Matt

Thanks Matt.

Appreciate you taking the time to share your findings.
No doubt more folks find it interesting, than are commenting.

Andy

I'll ditto Andy's comments, Matt...keep the posts coming.

And if you happen to contact Pat Rodgers anytime soon, kindly remind him he hasn't posted any project pics on Facebook since May. Marauder withdrawal is NOT a pretty thing!

_________________
It was a good idea, it just didn't work.

Thanks, lads. Will try to keep doing one of these a month, depending on what I can find. Oh and Dan, Pat has checked the thread before so he might be listening anyway

Next update will either be about ordering diagrams or about production numbers. Found a few sources claiming the real production was 5,288 Marauders instead of 5,266, will investigate and report back.
-Matt

Thanks, lads. Will try to keep doing one of these a month, depending on what I can find. Oh and Dan, Pat has checked the thread before so he might be listening anyway
[/quote]


Ask and ye shall receive...thanks Pat!!


Update pic of 40-1370...she's growing!


https://scontent-msp1-1.xx.fbcdn.net/v/ ... e=5F856E3B



And a pair from Pima's B-26B


https://scontent-msp1-1.xx.fbcdn.net/v/ ... e=5F85EE7C


https://scontent-msp1-1.xx.fbcdn.net/v/ ... e=5F84DDD5


(Linked unadulteratedly and unapologetically from Aircraft Restoration Services Facebook)

_________________
It was a good idea, it just didn't work.

Very nice progress on both of them, truly a lovely sight.

September/October Update

Hey everyone, today's update comes from two different sources.

First off, I have bought and read William Wolf's book on the B-26. I found the historical parts very interesting, and they did a great job of answering the many whys of B-26 production, including questions I did not even think to ask. For that and the great collection of pictures, it's a must-have resource for anyone who wants to learn more about the Marauder. When it comes to technical aspects, it's rather confusing. Wolf cites sources that contradict each other on both minor and major aspects, and his sections on maintaining and flying the aircraft mix information for the B-26 and B-26B-1, using mostly information from the latter. This isn't a big deal for me personally, since both flight manuals are available online for free, and I own copies of the maintenance manuals.

In terms of what I'll post in this thread, Wolf's book provides wonderful pictures of the multiple XB-26Es from various angles. I've posted them as URLs because linking them directly resulted in very large images. I might edit this post later to add resized versions of the images instead of links.
https://ww2aircraft.net/forum/attachments/img_0322-jpg.597301/
https://ww2aircraft.net/forum/attachments/img_0333-jpg.597304/
https://ww2aircraft.net/forum/attachments/img_0325-jpg.597302/
https://ww2aircraft.net/forum/attachments/img_0334-jpg.597305/
https://ww2aircraft.net/forum/attachments/img_0326-jpg.597303/

Secondly, I spoke to Pat Rodgers about the construction of the B-26's wing, since he has access to both a short wing and long wing model and I wanted to compare the two.

My theory was that the long wing retained the original wingspars and frames from the short wing model and merely had the large wingtip and new trailing edge sections attached to this original framework. I am still not entirely sure if that's the case or not. Pat has sent me pictures from a manual that covers both models, and while its diagrams seem to show both spars to be almost identical, it also shows that they have different part numbers (R-259001, 02, 03 & 04 for the B-26, R-360803 & 04 for the B-26B-1). The manual does not list measurements, so I'm not sure what the change is there. I currently still think both the old and new spars (as well as the old frames and new frames) share the same dimensions, but don't know for sure. I suppose I'll find out when I'm able to look at the microfilm.
https://ww2aircraft.net/forum/attachments/wing-1-b-26-jpg.597307/
https://ww2aircraft.net/forum/attachments/wing-1-b-26b-1-jpg.597308/
https://ww2aircraft.net/forum/attachments/wing-2-b-26-jpg.597309/
https://ww2aircraft.net/forum/attachments/wing-2-b-26b-1-jpg.597310/

Pat also let me know that there were changes to the leading edge, which I had not noticed. I tested this out by recreating an outline of both wings in blender, using dimensions from both aircraft's station diagrams as reference. Because the dimensions listed are all projections onto the horizontal plane, no calculations or angles were required. Sure enough, the leading edge and trailing edge are both longer in the B-1/C model:
https://ww2aircraft.net/forum/attachments/wing-comparisson-png.597311/

So, what now? Well, not much I can do until I'm able to look at the microfilm. I'll update the thread again if I come across more information.

Cheers,
-Matt

Thanks again Marty,
The changes in leading and trailing edges is remarkable.

_________________
Better is the enemy of Good.

Thanks, Adam! Hope you continue to enjoy this thread.

February Update

Hello everyone! It's been a while since I've updated this thread. I've kept myself busy with research and modeling, as well as returning to university. So, what is new?

The Spreadsheet

During the holidays I decided to try and rework my rather disorganized B-26 spreadsheet. My approach to this was to try and make one large table compiling all the dimensions and specifications that I could from manuals, general assembly/arrangement diagrams and station diagrams. In order to do that, I first had to write down all that information. This led to 15 different tables ranging from a dozen lines to well over 50 lines. I converted all measurements into inches and tried to color code said tables in regard to what reference plane the listed dimensions were on, with mixed results. I'm still not sure how to actually combine all of these into a single table, because the amount of information alone is overwhelming and it was not possible to use one standardized name for each dimension while first compiling the information. I'm open to suggestions on how to best process these individual tables into one single table. My main goal is to be able to make a table where the rows represent the individual parts and the columns represent the dimension of said part according to each source.

For example:
https://ww2aircraft.net/forum/attachments/capture-png.611922/

Current version of the spreadsheet can be found here.

The Wheels

Thanks to a few manuals on aircorpslibrary.com I was able to not only find out what wheels the different B-26 versions used, but also get dimensions and diagrams for them. I also compiled information for the wheels used by the B-25, XB-28, B-32 and XB-33, the ones for the two X-planes being mostly speculation based on what models where available in the described type (Smooth Contour, Low-Pressure, High-Pressure, etc) and diameter at the time.

Over the last few months I have modeled very high-detail versions of the early Marauders' nose and main wheels, the latter also with help from some ebay listings for B-26 wheels and brakes. The level of detail is almost certainly too high for a flight simulator model, but I figured it would make more sense to make the wheels as accurate as possible and later simplify as necessary if and when issues arise. The main wheel is particularly useful because my friend Jöel is working on a B-25 model, and the two aircraft share the same main wheels and brakes, though have different nose wheels. As such, Jöel was happy to use my wheels on his model and seems to be having no performance issues with them.

B-26 Nose Wheel (Bendix 57608, 33" diameter)
https://ww2aircraft.net/forum/attachments/wheel-nose-1-png.611917/
https://ww2aircraft.net/forum/attachments/wheel-nose-2-png.611918/
https://ww2aircraft.net/forum/attachments/wheel-nose-3-png.611919/

B-25/B-26 Main Wheel (Goodyear 53005, 47" diameter, with Goodyear 510675M 12.7x.100/.125x14 H.P. disc brakes)
https://ww2aircraft.net/forum/attachments/wheel-main-1-png.611914/
https://ww2aircraft.net/forum/attachments/wheel-main-2-png.611915/
https://ww2aircraft.net/forum/attachments/wheel-main-3-png.611916/

Other Stuff

Like I said, I'm back in university and as such I have a lot less free time now, so progress will be slow. I have however purchased a couple of more narrative-oriented books on the B-26, specifically Stan Walsh's The B-26 Goes To War (which I found very interesting and pleasent to read) and Dennis Gaub's Midway Bravery (Which I'm still reading). The two intersect at multiple times and it's quite interesting seeing different people's perspectives on the same events (Dewan vs Muri). I've also managed to get my hands on a used Monogram 1:72 B-26B-2 kit and am very happy about that.

The Future

Regarding the B-26 3D model, it's unlikely that I'll put in any more work until I am actually able to get the microfilm technical drawings from the Smithsonian, which will have to wait until the pandemic situation improves substantially. I will also probably purchase and read through Witold Jaworski's Virtual Airplane before properly starting, as I'm sure he has lots of tricks I can learn from to improve my skills. I will eventually model the larger low-pressure wheels used on the B-26B-1/C/F/G variants, but given that the early variants are my priority it will probably be a long time before I do. As for the spreadsheet, I am open to suggestions.

Stay safe & stay healthy y'all,
-Matt

Any idea where the hose attaches? https://scontent-lax3-2.xx.fbcdn.net/v/t1.6435-9/88370901_1443336325827767_3708624429538869248_n.jpg?_nc_cat=107&ccb=1-5&_nc_sid=8bfeb9&_nc_ohc=LznRuagwdQwAX9hDduE&_nc_ht=scontent-lax3-2.xx&oh=ac367a262143dfd43c622f8084465b5e&oe=61492E52

_________________
Better is the enemy of Good.