B-26 Dimensions & Diagrams (Outdated)

B-26B MA #41-17625 was converted to B-26B-3.

Greg Boeser said:

B-26B MA #41-17625 was converted to B-26B-3.

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Thanks for the info, Greg. The serial database presented it as a B-26B-3, which is odd because it usually only considers initial production. It being a conversion certainly explains how out of sequence the number is, since the other B-26B-3s are 41-7947 to 41-7973

Wolf reproduces the charts you are looking at in Martin B-26 Marauder: the Ultimate Look.
The Glenn L. Martin Aviation Museum lists #41-17704 as a B-26B-2, so I suspect that it and 41-17625 were pulled from the B-26B MA line for conversion to prototype -2 and -3 specs respectively, which is why they are out of sequence.

Greg Boeser said:

Wolf reproduces the charts you are looking at in Martin B-26 Marauder: the Ultimate Look.
The Glenn L. Martin Aviation Museum lists #41-17704 as a B-26B-2, so I suspect that it and 41-17625 were pulled from the B-26B MA line for conversion to prototype -2 and -3 specs respectively, which is why they are out of sequence.

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Well, sounds like I could've saved myself a lot of time by just buying that book. Then again, the afternoon of research was fun anyway. How well would you say the book covers the technical aspects of the Marauder? I have Wolf's book on the B-32 and it had a lot of great information.

Wolf's book has a lot of information gleaned from many sources. The editing is a bit choppy, and he doesn't spend much time weeding out incorrect information. So there are a number of errors in the presentation. Still, it's got a lot of info collected into one place.

According to my favourite book search engine the Tannehill book is readily available tho I personally would not buy it new.
I did not search for the Wolfe book.

Greg Boeser said:

Wolf's book has a lot of information gleaned from many sources. The editing is a bit choppy, and he doesn't spend much time weeding out incorrect information. So there are a number of errors in the presentation. Still, it's got a lot of info collected into one place.

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MiTasol said:

According to my favourite book search engine the Tannehill book is readily available tho I personally would not buy it new.
I did not search for the Wolfe book.
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I might look into purchasing either Tannehill or Wolf's books then, should have at least some information I'm not currently aware of. At this point this would be more for general documentation/research, as my main source for building the aircraft will be the microfilm blueprints. I'm hoping I can cover all Marauder production blocks, but my immediate focus will the B-26-MA, which I will hopefully be able to modify into the other variants.

It is the coolest one.

Kermit Weeks actually has a short wing B-26 in flying condition.

Greg Boeser said:

It is the coolest one.

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Agreed, 100%.

MIflyer said:

Kermit Weeks actually has a short wing B-26 in flying condition.

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I have suspected that his is in flying condition again now, or at least in the process of returning to it, since it seems to have gotten a new coat of paint. Would certainly be very interesting to get one of his Kermie Cam videos showing how to start it up and fly it, like the ones he's recorded for other aircraft.

Over the summer I was planning on emailing Kermit to see if I could visit his museum with a friend and climb aboard the 26, taking some measuring tape so I could measure the different parts of the landing gear and all the interior equipment, but sadly covid had other plans. Hopefully will still be able to do that, or at least see the aircraft in person, once I am able to return to the US, which should be January.

Small update. Still haven't purchased the book, but took a look at some of Martin's patents to see if I could find anything Marauder-related. There were a few things, most interesting of which is what appears to be a patent for an early form of the nose landing gear design:


Main changes seem to be that in the final plane the "scissors" were rotated 90 degrees around the strut, and the bottom one was mounted below the bottom part of the strut instead of above it. The landing gear bay and doors were also simplified. I did not find a patent for the main landing gear, the only main landing gear patent under Martin I could find was for the Baltimore

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.

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.


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:


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

I echo your sentiments on the Wolf book.

You may well be right about the spars. If they increased the thickness of the web or caps as part of an increased gross weight or to rectify a problem that had developed in service they would almost certainly give them a new part number because they are no longer interchangeable. The same applies if they have significant additional holes or fittings that exceed the tolerances the design office used to determine interchangeability.

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:


Current version of the spreadsheet can be found here.

The Wheels

Thanks to a few manuals on Air Corps. Library 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)


B-25/B-26 Main Wheel (Goodyear 53005, 47" diameter, with Goodyear 510675M 12.7x.100/.125x14 H.P. disc brakes)


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. It's currently assembled but not glued (and I might keep it that way for ease of transport), as I have yet to decide what livery I'll paint the aircraft in. I might make a proper thread about it in the modeling section of the forum, though bear with me if I do as it's my first proper model and I don't really plan on fixing imperfections and small gaps in the plastic.

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

Great stuff.
As always I am jealous of your talent

I'm jealous you found a Monogram B-26B-2
I'm stuck trying to modify a Monogram 1:48 B-26B-25 back to B-26B MA (70th Bomb Squadron modifications) I've got the short wing conversion kit with the small nacelles, short tail, and original nose cone, but the whole rear fuselage needs modification, since the B-26B-15 and later had the waist windows moved further back and eliminated the camera hatch. Plus the field mod observation windows were rectangular. At least the Monogram kit comes with the early tail cone of the B-26B MA to B-26B-10 B-26C-5. My initial hope was to make a B-26 MA, but the vacuform tail that came with the conversion kit was unsatisfactory. No way I could open it up a la 22nd BG style. I'm just not that talented.

MiTasol said:

Great stuff.
As always I am jealous of your talent

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Thank you very much!

Greg Boeser said:

I'm jealous you found a Monogram B-26B-2
I'm stuck trying to modify a Monogram 1:48 B-26B-25 back to B-26B MA (70th Bomb Squadron modifications) I've got the short wing conversion kit with the small nacelles, short tail, and original nose cone, but the whole rear fuselage needs modification, since the B-26B-15 and later had the waist windows moved further back and eliminated the camera hatch. Plus the field mod observation windows were rectangular. At least the Monogram kit comes with the early tail cone of the B-26B MA to B-26B-10 B-26C-5. My initial hope was to make a B-26 MA, but the vacuform tail that came with the conversion kit was unsatisfactory. No way I could open it up a la 22nd BG style. I'm just not that talented.

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That makes two of us on the talent front, Greg! I wish you the best of luck with your conversion, as it's sure to be tricky, and I hope you can find a better vacuform tail. If you find one in 1:72, let me know as I've tried but had no luck. Might keep it in its current B-26B-2 configuration, haven't decided yet. Only error I've really found so far on the kit is that the hole for the nose machine gun is placed in the bottom half of the nose instead of the top. I thought about simply placing the nosecone upside down, but I lack the skills to remove/disguise the bombardier's panel or make a new one. The side windows in the cockpit also seem a bit too short height-wise, but I plan on simply painting the glazing slightly higher up. If you do have the money for it, I'd suggest keeping an eye on ebay for these snap-tite B-26B-2s. I saw one back in mid-January and it was sold before I could buy it, then this one popped up only two weeks later!

Of course, mine is used, so I had to make a top turret mount out of a paperclip and glue the left propeller back onto its pin (propeller still spins so I'm quite proud of that). This kit is quite a looker even unpainted.

It has somehow been a year since I've posted in this thread, but not due to lack of research or work. I haven't had images I can share until a few days back, since I can't post the original microfilm scans. I've spent part of this semester and the previous one scanning several rolls of microfilm I purchased from the Smithsonian, and then trying to catalog them, which involves going through each frame and figuring out what the drawing is, what variants of the aircraft it applies to, etc. Scanning itself is quite time-consuming, taking around 8 hours if I make no mistakes, and quite a bit longer if I do. I had to retake half of the scans for one of the rolls earlier this semester, for instance. Cataloging takes even longer and is harder to do because it requires focus, while scanning is more just muscle memory. There's a lot of interesting stuff in these rolls, such as:

• Several diagrams on the XB-26D and its anti-icing system
• Inboard profiles for both the strafer and bomber versions of the XB-26E
• Some material on the XB-33 (Model 190)
• Some material on the Baltimore/A-30 (Model 187)
• Diagrams about all the tables, flooring and quite a bit of internal equipment
• Technical drawings for the individual frames (though lacking many of the dimensions)
• Technical drawings for the landing gear
• Armament diagrams

Recently though, I found the holy grail: ordinates tables. For the wingtips, for the stabilizer tips, for the entire fuselage and for the fillets, which makes me very happy as I had no idea how I was going to make those due to their complex shapes. Which is why I now have photos that I can share! The mesh itself will not look like this on my actual model as it intersects in odd ways, but it's excellent to have the ordinates themselves even if I don't know how to best use this information.

That's all for this update, hopefully I have more to share soon.

Also, War Thunder seems to have added a B-26, so I may get a bit sidetracked playing that game for a bit. I stopped years ago but... well, it's a B-26. They've done an excellent job with their model, especially the area around the cockpit, which is quite hard to do and many people don't get right. It does have its issues, some of them modelling related (main and nose gear are off, nose brace is in the wrong location, that sort of stuff) and others just nomenclature-related, such as just calling the 2 versions of the same model "B-26B" and "B-26C" instead of "B-26B1" and "B-26C". In general they seem to mix things from different variants, such as giving a long-wing B-26 the ability to drop torpedoes. While this isn't correct and I'd rather have a short-wing Marauder I do love that I will finally be able to torpedo things with a B-26. The modded B-26 in IL-2 1946 could also do that from what I recall, but I was just never able to aim the damn thing.

AirCorp will scan the microfilm at a very decent price level. I'll have t look back at the email with the cost info I got from Ester.