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World War II
Discuss WWII and the era directly before and after the war from 1935-1949.
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1/48 B-17F Build - 303rd BGs Luscious Lady
M4A1Sherman
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Posted: Saturday, June 15, 2019 - 02:08 AM UTC
Hi, All!

The B-17 has always been one of my favorites! I'm actually a P-47-"NUT", especially the -47s of 56th Fighter Group! The 1/48 TAMIYA P-47s RULE!!!

I currently have two unbuilt MONOGRAM 1/48 B-17Gs (including an original kit with the Shep Paine diorama folder enclosed in the kit), and a kit-bash REVELL B-17F that is also awaiting construction. I have ALL (plus) of the aforementioned after-market "goodies" that were mentioned in this thread, which has really started "my B-17-juices" flowing...

ABSOLUTELY GREAT to see the venerable 1/48 B-17 kits getting the attention they deserve...

BEAUTIFUL WORK!!!
Joel_W
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Posted: Saturday, June 15, 2019 - 01:21 AM UTC
This has turned into a B17-F history lesson that is beyond anything I've ever encountered as a modeler. The wealth of knowledge that both you and Karl continually post is just mind boggling.

I know that this has been brought up before, but you do realize that the two of you have the makings of the definitive B17-F modeling book.

Joel
Redhand
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Posted: Saturday, June 15, 2019 - 12:26 AM UTC
Thank you again, Karl. The "oil breather" at the #11 position is a remarkable detail. The engine was designed to leak! I suspect that the other sources of leaks were due to design decisions that perfect seals weren't essential to maintaining things like cylinder compression etc, but the idea is strange to me nonetheless.

As an aside, the radioman of "Luscious Lady" told me that Studebaker engines were "notorious oil throwers" compared to Wright ones. I have to take that on faith I suppose.

Your reply explains so much and will make for a much more accurate model. At some point soon we should also address staining patterns on the wing bottoms from the turbo exhaust and other sources.

Thanks again.

KPHB17FE
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Posted: Friday, June 14, 2019 - 10:56 PM UTC
There was no staining coming out of those vents despite what you see so many modelers do to the contrary (also, the people who did the "weathering" for the Memphis Belle movie did the same thing, making some people believe that is correct. It is not.). There was only warm air coming out. So many modelers have "exhaust" stains behind those. To start with, the exhaust exits through the turbos. You know, on the BOTTOM of the wing ... Most of the staining you see on the nacelles is from oil. For whatever reason, the crankcase is vented inside the cowling. Initially, the oil starts staining the cowl at roughly the 11 O'clock position as that is where the vent is located. As the airplane builds hours, the oil blows around inside the cowling and so you get more oil staining around the cowl. Plus radials just naturally leak oil, so more staining appears. You will occasionally see some exhaust staining on the cowls but that is generally brownish or blue tinted from overheating. You don't allow those to continue because otherwise the exhaust gases will cause serious damage. Back to the oil stains: You will see in photos from above, the oil flowing around and between the cooling air slots.

As for the contrails, they have two sources. The hot air coming from the exhaust and from the vortexes caused by the prop tips and the wingtips. The air coming out of the vents is not that warm.

Here is where the crankcase breather is located:



In this photo, you see nice new Forts waiting to be delivered to bomb groups after being ferried to England. And the oil vent has started making a mess to the left of center:



In this well known image of "Miss Donna Mae" going down over Berlin, you can see how the oil blowing back varies on each engine due to the prop wash and airflow off of the fuselage:



Here is an airplane with some hours on it and the darkest streak is still more or less lined up with the breather. No 1 has some other issues and 2 and 3 have dumped enough oil that it is staining behind the cooling slots but the slots themselves are clean:

Redhand
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Posted: Friday, June 14, 2019 - 10:07 PM UTC

Quoted Text

There was no screen on those vents. They were (are for that matter) wide open. They allowed air that has passed through the oil coolers and intercoolers to escape. This diagram shows the intercoolers. The oil coolers are between the engines.




Scratch calling them "fuel vents" then. This makes infinitely more sense, especially relative to the air intakes in the wing leading edges.

What accounts for the staining around the vents that we see in so many pictures and film clips? All I can figure is that it is some kind of condensation stain when the escaping air, which is heated by contact with the recycled exhaust air in the intercooler piping, comes into contact with the colder air at the vent opening.

I just had a eureka moment! These vents are also the source of the condensation trails we see in so many films, no?



Thanks as always for your input, Karl!
KPHB17FE
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Posted: Friday, June 14, 2019 - 09:29 PM UTC
There was no screen on those vents. They were (are for that matter) wide open. They allowed air that has passed through the oil coolers and intercoolers to escape. This diagram shows the intercoolers. The oil coolers are between the engines.



Redhand
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Posted: Friday, June 14, 2019 - 01:24 PM UTC
WING FUEL VENTS AND ATTENTION TO DETAIL

Here is some of H.G.'s work on the wing fuel tank vents -- opening them up.

Here we can see that the process starts with a drill hole on the side of the opening.



Here is how he does it.


Quoted Text

1. use a drill bit smaller (2/3 or 65%) than the height of the opening. Drill holes close to the edge of each vent side.

2. flip the part over and grind the material a few mm to make it easier to drill the rest of the holes for that vent and remove material.

3. flip it over again drill a third hole in the middle

4. then [drill] two more to make [five holes].

5. Use a micro saw to remove [the] material between the drill holes and then a # 11 blade to remove more to get close the vent's opening rectangular shape. DO NOT cut too much away for fear of over removing.

6. use micro sanders or files to smooth the irregularities. A good pair of magnifiers will help.






And you get something that looks like this.


He's also considering placing some metal vent work in the apetures:




Question for Karl: What was in there? Do we know?

Here is a view of the port wing with all vents opened.


And here is an image of the vents on the stbd. wing.



Finally, you may recall that when I started this build blog lo those many years ago I called my own skill set that of an "advanced journeyman." What follows bears that out, as I would never have seen during construction the fault in one of the lower wings that H.G. now proceeds to correct.

There was a subtle depression in the port lower wing indicated by the dark line running through the middle panel. See it?



Now, with the use of a mini sander, it's gone.



I see a true eye for detail and perfection at work here. Also, an artist's ability to see things and plan in advance that others don't.

Enough said for now.
Joel_W
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Posted: Friday, June 14, 2019 - 12:53 AM UTC
Brian,
Personally, I can't wait to see just what HG accomplishes with those wheel wells.

Joel
Redhand
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Posted: Thursday, June 13, 2019 - 11:15 AM UTC
WHEELS and WHEEL-WELLS

Let's start with the wheels. To review, "Luscious Lady" had this style.



And here it is in 1/48th.



But which aftermarket brand? That's "True Details" to the left, IIRR, and a mystery brand to the right, which H.G. and I think looks better. Here's another look at it:



You'll note that this vendor features three B-17 main wheel tread patterns.



(Yes, ours is the one in the middle).

And the mystery vendor is: Def.Models, a German vendor with a pretty neat catalog! http://defmodel.com/



However, the tailwheel is from the Verlinden aftermarket set.


Moving on to the wheel-wells, this section is more of a teaser than anything else, at least for now.



But ultimately, H.G. is going to "go there" and create something like this.








Clearly, there is a lot of research before actual building begins.
Redhand
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Posted: Sunday, June 09, 2019 - 01:17 AM UTC

Quoted Text

Simply amazing. The ignition wires are the best I've ever seen. All exactly the same length depending on which cylinder head plug location, and each in the proper place. Something that I always struggled with, and never got close.

Joel



Agreed.
Joel_W
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Posted: Sunday, June 09, 2019 - 01:03 AM UTC
Simply amazing. The ignition wires are the best I've ever seen. All exactly the same length depending on which cylinder head plug location, and each in the proper place. Something that I always struggled with, and never got close.

Joel
KPHB17FE
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Posted: Saturday, June 08, 2019 - 10:05 PM UTC
That's a beauty!
Redhand
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Posted: Saturday, June 08, 2019 - 04:52 PM UTC
READY FOR THE TEST CELL!



Hot off the production line:





I literally could not have done it * * * any better myself (attempt at subtle humor ) Seriously, I doubt I could have pulled this off.

And here are some views of the engine test fit to the wing.





But it's real home is the #4 engine position.







If you are wondering about the holes in the background styrofoam, there's a reason.

We are planning three "aluminum" Studebaker engines for the rest. The weathering on each will be different, to suggest different phases of the engine's service life. And some will have aluminum ignition wires, others brass. The numbered holes will keep them from getting mixed up.

I hasten to add that H.G. is not yet finished with #4. It also has to be weathered, even if "new"; and there are many additional details to be highlighted and completed still.

Moreover, H.G. specifically asks me to point out that:


Quoted Text

Back ring needs to be put on but I'm flipping a coin as to if that should be done now or at the time each engine is test fitted to the plastic. There will be plenty of handling at that time. But this will do for now and after they are all mounted the gloss black will touched up. Of course the shaft has to be removed yet it makes a great handle to hold them. ALSO, and this is a huge one, if I find a way to make this one look better as we progress then it will be done. For example, I know there are very fine wires that have the braided look which are made for bike models. [Please] mention * * * that if an improved version can be done then this one will be dismantled. Yeah I plan for that.



As someone who ripped out the nose of this model and completely re-did it, I can relate.
Redhand
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Posted: Saturday, June 08, 2019 - 04:24 PM UTC

Quoted Text

Ah but: Part of what caused the legend of "One a day in Tampa Bay" with the B-26 Marauders was the electric prop. Apparently they didn't always get the best maintenance or parts at the training bases. SO batteries were not maintained and on take-off, where the props were putting a big demand on the electrical system, the batteries were not providing enough back up and the props would go to a flat pitch. Prop not moving any air backwards, airplane not go forward... Airplanes will always figure out new ways to kill you.



They were not without their problems.
KPHB17FE
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Posted: Saturday, June 08, 2019 - 12:33 PM UTC
Ah but: Part of what caused the legend of "One a day in Tampa Bay" with the B-26 Marauders was the electric prop. Apparently they didn't always get the best maintenance or parts at the training bases. SO batteries were not maintained and on take-off, where the props were putting a big demand on the electrical system, the batteries were not providing enough back up and the props would go to a flat pitch. Prop not moving any air backwards, airplane not go forward... Airplanes will always figure out new ways to kill you.
Redhand
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Posted: Saturday, June 08, 2019 - 10:55 AM UTC

Quoted Text

On the B-17, the lever on the control stand was connected to the cables and pulley, that was how RPM was set. Then the flyweights kept it as set automatically. On the B-24, there was an electric motor to control the flyweight tension. And this is totally different from electrically controlled props. We won't even get into that!



It's starting to become clear to me now. Of course those controls would be on that console between the pilots!

You are right that the Curtiss Electric props are a different animal. Angle-of-attack on the blades and feathering was powered by an electric motor in the hub, not hydraulic pressure.


I understand that they were preferred in combat because there was less to go wrong if one had to feather an engine. An oil leak in a Ham Standard system due to battle damage was a greater risk than electrical failure in the hub motors. That's why the B-29 atomic bombers had Curtiss-Electric props., etc.

But I digress and stray off topic.


Joel_W
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Posted: Saturday, June 08, 2019 - 04:41 AM UTC
Karl,
You're a wealth of knowledge that most likely no one else can come close to.

In many ways you remind me of Steve Zologa who started as an armor modeler, and a member of the LI Scale Model Society; a chapter of IPMS region #1. His models were far beyond what the mortal modeler could do as he researched everything to the nth degree. Slowly but surely he stopped modeling and just researched and studied armor. The rest is history as just about everyone I use to know in region #1 deferred and referred to him .

Steve has written books on WWII armor, and has been on the History channel numerous times when the programs deal with WWII Armor.

You're his equal when it comes to B-17s for sure.

Joel
KPHB17FE
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Posted: Saturday, June 08, 2019 - 02:03 AM UTC
On the B-17, the lever on the control stand was connected to the cables and pulley, that was how RPM was set. Then the flyweights kept it as set automatically. On the B-24, there was an electric motor to control the flyweight tension. And this is totally different from electrically controlled props. We won't even get into that!
Redhand
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Posted: Saturday, June 08, 2019 - 01:56 AM UTC

Quoted Text

and it is wholly automatic after it is set.



Thank you Karl! If anyone knew in this day and age, I knew it would be you! And I see that human input was required to "instruct the system what to do," i.e., full flat pitch on takeoffs, etc.
KPHB17FE
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Posted: Saturday, June 08, 2019 - 01:46 AM UTC
I will see if I can explain this (sort of ). The cable you see controls spring tension on some rotating flyweights. This controls the amount of oil going to the prop. As the speed varies, the flyweights change position which in turns varies the amount of oil flowing to the prop. Inside the prop dome is a piston which controls the mechanism to control the pitch of the prop. Hard to explain but trust me, it works fine and it is wholly automatic after it is set. One of the lines you see in the photo I posted before is for normal oil to the prop. The other line is from the feathering pump. The electrical connector is for feathering. When the feather pump is on, the pressure bypasses the governor and goes direct to the prop dome, driving it to feather. When the pressure reaches a certain point (400 PSI comes to mind), the feathering pump shuts off. To unfeather, you hold the feathering button in (to bypass the earlier switch) and when the pressure builds up to 600 PSI, the prop unfeathers (the oil pressure is directed to the other side of the piston using a bypass valve). You can then control it normally. The one in my photo has an external line for supply so that is probably a -65. This diagram is from a B-24 manual and has an internal supply which I think is what the 1820 -97 had. I am too lazy to look it up right now. Anyway, the system works the same on both airplanes. EDIT: The dash 97 has the external supply line. That's what I get for trying to work from memory!



What can I tell you, the B-24 manuals have some great illustrations (auxiliary is pressure is from the feathering pump):



One more:

Redhand
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Posted: Saturday, June 08, 2019 - 01:09 AM UTC

Quoted Text

Brian,


As far as the manual cable override of the auto pitch control, could it main function be for when the aircraft is idling and stationary? I'm sure that Karl has the answer or a really very educated guess.

Joel



Perhaps the good, old-fashioned manual override way is preferable to "fully "automatic," when we consider a more recent Boeing product - the 737 Max.
Joel_W
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Posted: Saturday, June 08, 2019 - 12:44 AM UTC
Brian,
The detail work on the engine is simply beyond anything I've ever seen. The pulley system's cable even has a realistic slack to it.

As far as the manual cable override of the auto pitch control, could it main function be for when the aircraft is idling and stationary? I'm sure that Karl has the answer or a really very educated guess.

Joel
Redhand
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Posted: Friday, June 07, 2019 - 11:16 PM UTC
MORE ENGINE DETAILS

Here we see H.G.'s work on the 1/48 propeller governor.



With this closeup.



Compared to the real thing on at least one engine.




I remain somewhat mystified by how this thing works. The props are Hamilton Standard "Constant Speed" propellers, which means that hydraulic fluid feeding the propeller dome "automatically" adjusts the blades' angle of attack to maximize aerodynamic efficiency at the engine's rpm setting (while minimizing fuel consumption). Or some such. And indeed on this governor control, there is piping at the bottom. However we see the flywheel with the control cables leading to one of the baffles, and the tech literature confirms that these cables lead directly to controls in the cockpit.

So it's obvious there was pilot input into this "constant speed" system. But why, if the system is supposed to be automatic? I think we're stuck in WWII technology where "automatic" really means "partially automatic." It's a puzzlement, or I betray my ignorance as a non-pilot who should "Keep yer hands out of the cockpit!"

Finally, below is another picture of the WIP engine. The gloss black rocker arm covers on the cylinder heads are a nice touch.

Joel_W
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Posted: Friday, June 07, 2019 - 05:01 AM UTC
Brian,
At the rate that you and HG are going, you'll have all 4 engines done sooner then later.

Those ignition harnesses are amazing. Measuring each wire against the PE part really is paying major dividends now.

Joel
Redhand
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Posted: Friday, June 07, 2019 - 02:35 AM UTC

Quoted Text

Lookin' good! I have a couple sets of those engines but have not had the courage to take them on. I'll watch here



I had the same reaction to the Brassin set when I first got it. "Way cool!" But on closer examination the intimidation factor set in. They really are beyond the "some modeling skills helpful" level.