Ken wrote:
Not sure there was ever a tail gun position on the B. When you look at the tail evolution from the NA-62 through the B-25G, the various stinger glass configurations are, as you say, mostly an observation post
I believe our friend is refering to the elimination of the tail gunner position in the B model from the earlier versions of the B-25. The B-25A had a single flexible .50 caliber machine gun in the tail.
http://www.nationalmuseum.af.mil/shared ... 4S-003.jpgwarbird1 wrote:
4) Why was the tail gun removed from the "B" model? What was the purpose of the clear plexiglass encasement over the tail if there was no gunner? Was it simply for observation to look for enemy fighters or perhaps to take pictures for battle damage assessment or what?
This was removed because it was thought that between the newly added dorsal and ventral Bendix gun turrets that the rear of the aircraft was sufficiently defended. Also with the addition of the dorsal and ventral turrets the armor plating and rear gun mount was removed to help offset the additional weight of the turrets. The rear bubble was simply an observation point. Later the H model introduced the elimination of the ventral turret and the addition of the 2 .50 caliber machine guns in a tail mounted Bell turret. That is when the dorsal turret was moved forward to maintain the wieght and balance because of the additional wieght in the tail.
warbird1 wrote:
5) Why did they use an exhaust collector ring on the "B" model, but yet went back to the individual exhaust stacks on the war time "J" models?
During C model production blocks there was some experimentation with exhaust configurations. This was due to B-25Bs and early C being pulled from night operations due to the very visable flame that would protrude from the early collector ring exhaust pipes. This was a giveaway to the enemy during night operations. There were soem changes made with partial collectors but this was found to be a weak design and would result in the semi collectors cracking. They opted for the Clayton "S" stack design to elimnate the visable flame issues and the semi collector cracking.
Ken wrote:
My impression is that they increased power while removing some complication/easing maintenance.
Unfortunately, the design did sacrifce a few miles per hour in speed but it was considered a good trade-off for the additional benefits.
b29flteng wrote:
The post war TB-25 partial collector exhaust (Hayes mod) was for carburetor heat.
You are exactly right. This is also why the Harker's from C&P Aviation decided to keep the later model collector ring on "Betty's Dream." With the cold of Minnesota they opted for carb heat over the original J model “S” stacks on the top cylinders.
warbird1 wrote:
6) Are the glass noses interchangeable on the B,C,D and J models, or are they all slightly different? Could the same one be used in restoration for any of these models?
For the most part the answer is yes. When the C/D model replaced the .30 caliber flexible machine guns in the in the nose at the -5 production block with a .50 caliber flexible gun it introduced some minor changes to the glazed nose that resulted in some additional reinforcing at the gun ball mount point. In the J model when the factory added additional forward firing machine guns to the starboard side of the nose it did change the nose “glass” by adding some additional holes for the guns to protrude however the frame was not changed. The PBJ-1C/D had several aircraft fitted with the rather ugly radome that protruded from the top of the glazed nose. Additionally some of the post war- B-25Ks and others had radomes attached to the front of the glazed nose. Essentially there were slight modifications to the glazed nose depending on the type of hardware that was used in the nose however the basic frame of the glazed nose was not changed throughout production and one nose would “fit” on another model aircraft and could be easily modified to fit whatever hardware was included in that model.
warbird1 wrote:
8. Regarding the last surviving "B" model owned by Aero Trader out in Borrego Springs in storage. I've only seen pictures of the fuselage. Do they have the wings also? If not, could other model wings be used - i.e. C, D, or J models? How easy would it be and how much modification would it require? I know given enough money anything is possible, but is it practical, or would a scratch built "B" model wing have to be built?
Aero Trader does not have the wings for the B model. They basically have the fuselage from the nose to the tail. The wings were cut from the center section. The wings are essentially the same on the B-C-J models. There are some differences mainly due to different fuel tank configurations however structurally they are the same and outer wing panels can be used from aircraft to aircraft. The biggest issue of course is that the wings were cut from the center section and the wing and nacelle sections are missing. The center sections are structurally very similar between the B and C/D model and Carl has told me in the past that the B model fuselage can be adapted to the J model center section with some reasonable modifications.
warbird1 wrote:
1) Were any "B" models, besides the Doolittle ones, used in any combat zones by the United States during the war? If so, can anyone post pictures, and provide info on what units, locations, time used, etc.?
I'm not a super guru on combat operations however I don't think that the B-25B made it to any over-seas combat zones for the purpose of being inovlved in combat operations (out side of Doolittle Raid). I wouldn't be surprised if some made it over-seas as squadron hacks or being used as transports. Most of the early Medium Bomber Wings that had flown B-25Bs at one time or another in the States (I think 12th,38th, and 42nd) ended up being first deployed with (again I'd check these facts around the combat deployments as it has been years since I studied them) 12th BG with B-25C/D, 38th BG with B-26s, 42nd B-25 C/D.
The B-25Bs did however
have some use in the role of anti-submarine partol aircraft.
Hope that helps. Thanks, Ryan
edited for accuracy by RWDFRESNO