Tag Archives: “Oxygen Bottle”

Monogram de Havilland Mosquito, kit problems, cockpit/interior colors

Hi friends,

I have always thought Mosquitos were Pretty Darn Cool. I’m also an avid model builder and enmeshed in the coils of a typical “Advanced Modeler’s Syndrome” (AMS) situation I’m attempting to build a reasonably accurate 1/48 B/PR Mk IV (series II) from the old Monogram kit. (hahahaha! Yes, I now have the Tamiya B/PR Mk IV… its a long story.)

I’m hoping to build DZ411 in its BOAC markings.

Putting the kit parts up against templates from scale plans revealed the following problems, all no doubt known but I’ll list them anyway:

* Fin and Rudder about 1/4″ (6mm) too tall. (Either Modeller’s Datafile or AeroDetail give a correction drawing…)
* Horizontal Stabilizers not wide (span) enough.
* Fuselage is too square in cross-section.
* Fuselage is .140″ or about 3.5mm too NARROW, though wing tips are the right distance apart.
* Cockpit, bomb bay, nose compartment not quite the right shape, under detailed, inaccurate.
* Main and tail wheel wells are completely empty except for gear legs. Main gear well should have bulkheads fore and aft, engine oil tanks, gear retraction mechanisms, ribs and spars visible. And underside skin as well as the inside of the topside skin visible. Tail wheel should have a mud-guard inside the well.
* Main gear legs rake too far forward. Mud-guards have one, large, stiffening rib, should have two, large, ribs
* Propellers too small in diameter.
* Pilot and observer seats are the same- should be different! Nose compartment interior entirely fanciful. Rectangular windows in the wrong place and oddly shaped. Nose transparency to fuselage joint 1/8″ or more in the wrong place.

So far I’ve

> widened the fuselage 0.040 by inserting a strip of styrene between the two halves
> started to approximate a cockpit using styrene stock, the True Details Mk II/Mk IV resin set, and 3 parts from the kit, the two fuselage halves and the bomber control yoke!
> inserted bulkheads fore and aft of the main gear door cutout
> Added wing ribs, underside skin and spars in one main gear well
> made a couple of trivial oil tanks for the gear wells
> sawn off the rudder and fin (oops- I can now see it can be trimmed as it sits)
> Figured out how to stretch the horizontal stabilizers: cut the top and bottom halves but not at the same spot, so one side overlaps the cut on the other side. Insert styrene stock to fill.
> schemed how to scab 0.05″ on the outside of each fuselage half if I decide to, while preserving the original wing root location. (Have to cut through extra for the wing… ugly…
> Considering improving the main gear legs
> Ignoring that the nacelles may be too close to the fuselage and thus props too small (should be 12 feet 0 inches, 3 inches in 1/48 scale)- I haven’t measured them or the spacing yet!
> bought two sets of resin exhausts (5 on a side) to use to fake-up the 6-on-a-side on the outside setup my reference pictures show
> Got the BOAC markings for an FB VI, mostly corrrect for the B/PR Mk IV.
> schemed how to widen the nose and canopy clear parts and either use them as is or vac-form replacements over them…
> started drawing the plans I can’t find for the cockpit and wheel wells.

And that brings us to the questions I’m hoping someone has answers for:

Fire Extinguisher Color:
I count 3 fire extinguishers one clipped between access holes on the front of the rudder pedal box, one clipped near the floor at the Observer’s feet, one clipped to the Port cabin wall for the pilot to use. What * C O L O R * would 1941-1945 RAF cockpit extinguishers be? The rare, old, item in a surviving airframe is a brownish dull red is that weathering or correct?
An informant tells me the fire extinguisher was copper on the outside weathered to reddish brown, like a penny.

Emergency Oxygen tank Color:
The box/rack visible from the front on the starboard side of the nose contains emergency/portable oxygen. The main tanks in the fuselage are black. What * C O L O U R * are the emergency O2 bottles, 1941-1945?
From pictures I’ve found subsequently, I’d say black works, as does silver (aluminum).

Emergency/Portable Oxygen bottles appear to have a pressure gauge and valve. Colors? Appearance? Any detailed photos somewhere?

Regular oxygen flows from six tanks in the aft fuselage through valves at each crew station and into “Economizer, Oxygen Mk II”s. Are there two of these, one for each, or 3, one for each seat and one for the nose? – Ah, got this one. I can see from all my photo references that there are two and only two Economizers in a Mosquito cockpit. One for the Pilot, one for the Observer. I suppose the BOAC birds carried an extra one for the passenger. What an Economizer, Oxygen, is is a boxed version of the little plastic sack between the source hose and the mask on your emergency oxygen masks on airliners the Economizer is a place where oxygen can gather while you are not inhaling there’s a non-return valve that closes when you’re not inhaling, and the old oxygen systems such as the one in the Mosquito weren’t actually demand systems you set the knob for a given flow rate. Without the economizer, what you didn’t breathe in would simply dump into the cockpit, hence the name “economizer”.

Anyway,  I’ll post these answers on the Mosquito forum tomorrow.

What colour are the hoses which carry O2 treated breathing air?
Couldn’t be easier they’re all around the cockpit. They’re white.

The floor-boards between the pilot’s seat and the rudder pedals look smooth and reddish-brown phenolic board? A wood product? Have I got that color right? Still seems like dark brown, I’m going with it.

The throttle has two levers outboard, on the far left, which have round, black, knobs. There are two levers inboard, on the far right of the throtle quadrant which have square, often orange yellow handles. The quadrant itself seems black, with bare aluminum trim and placards, and a red button on the inside (toward the pilot) at the back end.
Are those colors correct for 1941-1945? Is the yellow-orange for real? I’d still like to know.

In the aft part of the engine nacelle, the rear spar cuts diagonally across the bay containing the main gear when retracted. Are the two radius rods that anchor the gear to the rear spar the same length, or do they stagger to match the slant of the spar? Still not sure (reason suggests they’re the same so they hinge the same… but I’ve seen a photo of at least one wheel well showing these to be silver in color same “Aluminum” paint as the rest of the landing gear.

Along the aft bulkhead, does the aft bulkhead come down vertically, parallel to the sides of the opening for the wheels? NO! It comes down at a slant, the bay is slightly larger at the bottom than at the top (top is top)

I have more questions, but this is a good start. There are still some questions there, but I’ve got most of it.