Historical Fragments #3:
Notes for “26 Missions”
Wally Lee Parker
(member: Clayton/Deer Park Historical Society)
(all rights to this material retained by author)
… initial thoughts …
Currently I’m trying to put together a story about one of Deer Park, Washington’s, WWII veterans, Staff Sergeant Robert Willis Grove — Enlisted Bombardier / Armorer / Left Waist Gunner — 407th Bombardment Squadron, 92nd Bomb Group (Heavy), 8th Army Air Force. One piece of this story will involve the several well-known tail damage photographs reproduced here. Among the other pieces comprising the completed story will be an outline of the Grove family’s long history within the Deer Park community and Willis Grove’s twenty-five other B-17 missions over wartime Europe.
Tail damage to B-17E #41-9020.
Army Signal Corps photo taken on October 5, 1942, at Bovingdon Airfield, England.
(Photo courtesy of Gordon Grove.)
I suppose the Willis Grove story could be sketched without any detailed exposition — meaning without discussing anything requiring in-depth research. And that would be easiest. Willis passed away some time ago, so I can’t ask him to tell his own story and then just transpose that into script. His absence from the project means I don’t have his words to direct me toward what I need to know in order to stitch this story together. So as noted, I could just lay out the several remarkable wartime photos his son, Gordon, sent me as a photo essay without looking any deeper. But I think there’s something unique about this soldier’s story that needs to be told — something unique that only further research can reveal.
Willis Grove represents a generation of teenage and barely older boys who went off to war and by-in-large came home to live quiet lives, seldom saying much of anything about what they personally did or how they personally felt about the war. It’s only been in the last quarter century, as their numbers have noticeably dwindled, that the soldiers of World War II have begun to show that literally none of them came away from combat without to some degree being torn. When they do talk — in those moments when their eyes glisten and maybe a drop or two of tear rolls free — it seems most of the pain recalled isn’t for the harm done to them personally by either circumstance or the enemy. Rather the tears are for those dimly recalled friends left behind almost seven decades ago — those dimly recalled faces destined to never age.
From the summer of 1942 until the summer of 1943 Willis Grove was caught up as part of the largest air armada the world has ever seen. He was taking part in an aerial campaign of scorched earth as first envisioned in the waning days of World War I by Winston Churchill, among others. He was taking part in what, at that time, was very much an experiment that no one was sure would work. He was very much part of an experiment in calculated attrition.
The story that needs to be told here involves fear and the will to overcome it. After all, the one thing these boys quickly developed was an appreciation for the amount of jeopardy doing their duty placed them in. That’s very much a part of this story — the fact that these young kids, despite knowing the risk, went into the air again and again and again.
The object now is to start gathering the parts for this story. At some point the various parts will begin to find and settle into their own place. And then, hopefully, we’ll discover that the story has written itself.
… our windows began to frost up …
These are the words of Lt. Eugene Wiley, pilot, regarding the mid-air collision of his B-17 with a B-17 flown by Lt. James Dempsey Jr. during the early part of the 8th Air Force’s October 5th, 1942, mission to Lille, France — what was to have been Willis Grove’s first combat mission.
“As we climbed out over the North Sea into the sun, our windows began to frost up, the silica gel from the old E’s needed replacing and it was not doing the job of removing the moisture in the windows. The sun and frost made it extremely difficult to see.”
Thought visibility was only one of the factors in the collision, from the first hand reports on the incident it’s apparent that visibility did contribute. And that contribution has drawn up a set of research questions regarding the windscreens on the B-17s.
The following is a background description of part of that visibility problem. Since the paragraphs below are just an attempt to lay out the essential facts, the words used in the actual article are likely to be significantly altered during the many rewrites yet to come.
The windows on the B-17 bomber were glazed with two types of material — laminated glass and clear plastic. Discovered in the late 1870s, and first produced as large, visually clear sheets in the 1930’s, acrylic (aka polymethyl-methacrylate or PMMA) was the substance of choice for the complex curves of the B-17’s “greenhouse” nose. As for the craft’s glass windscreens, those were composed of two sheets of glass bonded together by thin films of clear, tough, flexible plastic — the same type of lamination process used in today’s automobile windshields. Though the lamination process did increase the windscreens’ resistance to impact, more importantly any glass shards produced by a broken window tended to adhere to the bonding plastic rather than spraying throughout the aircraft’s interior — and the laminated glass, even if essentially shattered, could still remain intact enough to deflect the onrushing airstream.
The primary function of the various windscreens was exactly that — allowing visibility while shielding the crew from a pristine airstream that could, at altitude, reach temperatures of minus 50º Fahrenheit or more, and — by adding the effect of wind-chill to such frigid air — produced a heat eroding cold that could freeze bare flesh in seconds.
During the combat phase of missions, the airstream was far from pristine. Often filled with energetically propelled bullets and flack, it also contained a metallic grit of sorts; grit composted of spent munitions falling toward the ground with, on occasion, pieces torn from other aircraft mixed in. While some of the B-17’s windscreens — such as the tail gunner’s aft-looking sighting window — were extra thick, none were expected to deflect a still potent bullet hitting straight on. However, against smaller metal fragments dropping through the sky solely under the influence of gravity, laminated glass could provide the crew of an onrushing aircraft at least some protection.
Certain B-17 windscreens were double-glazed as an anti-frost measure. Reportedly the pilot and co-pilot’s forward facing windscreens, the cabin’s sliding side-windows, and the pie-shaped, flat laminated glass bombardier’s segment of the otherwise acrylic nose of the bomber were all double glazed — meaning two panes of laminated glass separated by a dead-air space. The sighting windows for the turret, ball, and tail gunner were also anti-frost.
The bombers did have a cabin heating system. Glycol (in this case a 55/45% mixture of diethylene glycol and ethylene glycol), pumped through a metal coil in the exhaust stack of the left wing’s inner engine — engine #2 — was heated by the glowing combustion gases (reportedly the area of the exhaust stack in which the coil was situated could reach up to 1600ºF). The glycol was fed through a duct-enclosed radiator mounted inside the left wing close to the fuselage. Fresh air drawn from an extraction port in the #2 engine’s intercooler intake was routed through the ductwork. When passing through the radiator the air was heated. The heated air was then vented into the aircraft’s heating system.
Ductwork inside the floor of the fuselage diverted a portion of the incoming heated air to vents opening under the pilot and co-pilot’s windscreens, and to the bombardier’s sighting windscreen. As for effectiveness, one former B-17 crewman reported that those were the most effective of the aircrafts heating vents, stating that more than once he’d noted the cabin’s unheated side-window covered with “hoarfrost,” while the pilots and bombardier’s windows were clear.
Then of course there were the windshield wipers — one would assume only useful for clearing mist or rain from the windscreen while sitting or taxiing.
But Lieutenant Wiley’s description of the visibility problem specifically included the phrase, “the silica gel from the old E’s needed replacing and it was not doing the job of removing the moisture in the windows.”
When Lieutenant Wiley described the “moisture in the windows,” he’s referring to a specific problem mention on page 375 of 1942’s “Technical Order Number 01-20EF-2,” — also known by the more explanatory title, “B-17 Erection and Maintenance Instructions.”
Under the heading “assembly and installation” of “windows,” one paragraph states, “The dehydrator unit is designed to assure complete absence of moisture in the air or gas trapped between the panels and the success of the defroster equipment depends upon the maintenance of a dry air condition.”
What’s being referenced is the dead-air space trapped between the double-panes of the aircraft’s anti-frost windscreens.
It’s likely that the glass panels of the double glazed windscreens were held separate by a rubber gasket, and then sealed into their frames with some type of calking. The necessity of using a “dehydrator unit” as noted above suggests that air-tightness — in the sense of an absence of leakage — was not an expectation for the windscreens. Climbing would raise the pressure of the desiccated air trapped between the double panes relative to the lower pressure of the outside air. It’s likely the extreme cold found at altitude would both shrink and reduce the flexibility of the calking materials — speeding the outward leakage of the trapped and now relatively pressurized air. Once air had leaked out of the dead-air space, the increasing atmospheric pressure of descending flight would have pushed moist outside air back into the now reduced pressure within the dead-air space.
The dehydration unit was a visually clear, cellulosic plastic (aka Tenite) cylinder about one inch thick and ten inches long. The otherwise closed cylinder had a nipple fixed to one end so a length of rubber tubing could be attached. The cylinder was attached to the aircraft near the window it was intended to service, and the free end of the rubber tubing was connected to a fitting on the intended window. Once attached, the air in the dead-air space could circulate through the granular silica desiccant contained in the cylinder — the cylinder being what was referred to in the maintenance material as the dehydration unit.
As for how Wiley knew “the silica gel from the old E’s needed replacing” — other than the fact that “the windows began to frost up” — it was obvious from the color.
Despite being called a gel, silicon dioxide is a granular solid. It likely retains that name from the gel state it passes through during manufacture. The granules are colorless — in this case meaning white. To visually signal the presence of moisture, cobalt chloride is added to the gel. As the maintenance manual explains, the “presence of moisture in the dehydrating compound is indicated by a change in color from normal dark blue or dry condition to a white or light pink.
The manual goes on to say, “The silica gel crystals may be restored for re-use by baking at a temperature of 149ºC (300ºF) for 4 hours, or until all crystals regain their dark blue color. Discard cartridges or replace with new silica gel crystals after 20 reactivations.”
And finally the manual promises, “These precautions, when properly followed, will relieve any condition of fogged or frosted windows.”
… and yet to come …
If all goes well, you’ll begin to see this story condense over the coming summer. At some point you’ll have enough data to understand the story’s background, and I’ll have enough data to begin laying all these notes out as one linear script. We’ll see.
— As always, comments and corrections are welcomed. —