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- #121
Crimea_River
Marshal
A nice photo of our aircraft, CF-HMS taken at Mould Bay, NWT circa 1959
Mosquito RS700 Restoration
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- #122
Crimea_River
Marshal
Sister ship CF-HMK at Yellowknife, July 1956:
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- #123
Crimea_River
Marshal
My assignment over the last month or so has been to fix water damage at the port side window. Water had infiltrated the plywood and balsa layers at the bottom of the window opening necessitating injection of T-88 epoxy between the layers and clamping them. At the bottom, the layers were rotten and had to be replaced. I cut out the rotten plies, leveled the balsa, installed new plywood layers and then reattached the inner bolting strip whose glue had crystallized causing the ring to fall off.
This first pic shows the finished repair and build-up of the lower sill. The new wood can be clearly seen and does not yet have the holes for the glazing drilled. Please pardon the arm in the picture - another busy volunteer.
With the repair done on the opening, the bolting ring was reglued and clamped using temporary machine bolts inserted into the existing and newly drilled holes. The red stuff is vinyl packing tape and is used to protect the aircraft skin from excess epoxy that may ooze from the joints. The epoxy, we discovered, will not stick to this tape so it makes a handy mask.
This first pic shows the finished repair and build-up of the lower sill. The new wood can be clearly seen and does not yet have the holes for the glazing drilled. Please pardon the arm in the picture - another busy volunteer.
With the repair done on the opening, the bolting ring was reglued and clamped using temporary machine bolts inserted into the existing and newly drilled holes. The red stuff is vinyl packing tape and is used to protect the aircraft skin from excess epoxy that may ooze from the joints. The epoxy, we discovered, will not stick to this tape so it makes a handy mask.
Airframes
Benevolens Magister
Great stuff Andy, and wonderful work.
On the outside of these windows, is there a rubber sealing strip around the edge ?
Not sure whether to add one to my models.
On the outside of these windows, is there a rubber sealing strip around the edge ?
Not sure whether to add one to my models.
Lovely stuff Andy!
vikingBerserker
Lieutenant General
What a fantastic job!
When you saw Balsa wood, are you referring to the really soft light weight wood?
When you saw Balsa wood, are you referring to the really soft light weight wood?
Old Wizard
2nd Lieutenant
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- #129
Crimea_River
Marshal
Thanks everyone.
There is definitely another ring on the outside Terry but it's not rubber. Rather, it's thinn aluminum. See the detail below, parts A98191 and A98192
.
Yes David. The fuselage as made up of an inner and outer sheet of 1.5mm to 3mm birch plywood sandwiching 7/16" thick balsa wood, the same stuff used for R/C planes.
In the below pic, the outer plywood skin has been removed and I have labeled the sandwiched woods:
There is definitely another ring on the outside Terry but it's not rubber. Rather, it's thinn aluminum. See the detail below, parts A98191 and A98192
Yes David. The fuselage as made up of an inner and outer sheet of 1.5mm to 3mm birch plywood sandwiching 7/16" thick balsa wood, the same stuff used for R/C planes.
In the below pic, the outer plywood skin has been removed and I have labeled the sandwiched woods:
Airframes
Benevolens Magister
Thanks very much for that Andy, it's clarified everything.
Interesting that the plywood for the Mosquito was imported from America - darn, the Mosquito was American after all !!!
Interesting that the plywood for the Mosquito was imported from America - darn, the Mosquito was American after all !!!
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- #131
Crimea_River
Marshal
We could no longer get the replacement plywood here. A mill in Austria supplied it to the specified thicknesses and number of plies, all per the original British standard!
Airframes
Benevolens Magister
So it's an Anglo-American-Austrian-Canadian Mosquito !
I've got the documentary on the building of the Mosquito, which includes the production of the plywood, and its import, by sea, to the UK. Unfortunately, it's on a VHS tape, along with original footage from the Shell House raid, and I really must get it transferred to DVD.
I've got the documentary on the building of the Mosquito, which includes the production of the plywood, and its import, by sea, to the UK. Unfortunately, it's on a VHS tape, along with original footage from the Shell House raid, and I really must get it transferred to DVD.
The bulk of the Mosquito was made of plywood. Stronger and lighter than most grades of plywood, this special plywood was produced by a combination of 3/8" sheets of Ecuadorean balsawood sandwiched between sheets of Canadian birch plywood. Like a deck of cards, sheets of wood alternated with sheets of a special casein-based (Later formaldehyde) wood glue.
The specialized wood veneer used in the construction of the Mosquito was made by Roddis Manufacturing in Marshfield, Wisconsin, United States. Hamilton Roddis had teams of dexterous young women ironing the (Unusually thin) strong wood veneer product before shipping to the UK.
RAF Wyton - De Haviland Mosquito
The specialized wood veneer used in the construction of the Mosquito was made by Roddis Manufacturing in Marshfield, Wisconsin, United States. Hamilton Roddis had teams of dexterous young women ironing the (Unusually thin) strong wood veneer product before shipping to the UK.
RAF Wyton - De Haviland Mosquito
Old Wizard
2nd Lieutenant
A4K
Colonel
De Havilland Australia produced the Mosquito for the RAAF during the war, the first (A52-1) taking to the air at Bankstown, Sydney (NSW), on 23 July 1943.
This from 'Aeroplane Monthly' (January 2017) on the wood used in DHA manufacture:
All spruce and balsa for the primary structure was imported, but Australian timber was employed in many elements of the secondary structure. Initially, it was planned to use local coachwood ply in the wing skins and spar webs. This decision was later reversed, as related by Merv Waghorn, an engineer seconded from Hatfield who was delegated to make design changes: "The shear strength and shear (modulus) tests I did on coachwood demonstrated that, although it met the same specifications as (4 x 3) birch ply, it could not match (the) results achieved on birch ply at Hatfield using identical test conditions. I therefore made the decision to increase the spar web thickness for coachwood, the first major modification to the Mosquito developed in Australia.
"This proved to cause problems because it reduced the chordwise dimensions of the space into which the wing tanks were fitted and required reduction of the chordwise dimension of the tank doors, so that they were not interchangable with those on English and Canadian Mosquitos and made them hard to install. Before production was under way, the plan of using coachwood was abandoned and we used imported birch ply throughout, so the whole modification was unnecessary".
This from 'Aeroplane Monthly' (January 2017) on the wood used in DHA manufacture:
All spruce and balsa for the primary structure was imported, but Australian timber was employed in many elements of the secondary structure. Initially, it was planned to use local coachwood ply in the wing skins and spar webs. This decision was later reversed, as related by Merv Waghorn, an engineer seconded from Hatfield who was delegated to make design changes: "The shear strength and shear (modulus) tests I did on coachwood demonstrated that, although it met the same specifications as (4 x 3) birch ply, it could not match (the) results achieved on birch ply at Hatfield using identical test conditions. I therefore made the decision to increase the spar web thickness for coachwood, the first major modification to the Mosquito developed in Australia.
"This proved to cause problems because it reduced the chordwise dimensions of the space into which the wing tanks were fitted and required reduction of the chordwise dimension of the tank doors, so that they were not interchangable with those on English and Canadian Mosquitos and made them hard to install. Before production was under way, the plan of using coachwood was abandoned and we used imported birch ply throughout, so the whole modification was unnecessary".
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Old Wizard
2nd Lieutenant
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- #137
Crimea_River
Marshal
Big job done tonight. The outer skin plywood has delaminated at the middle seam due to water intrusion. The fix was done tonight by injecting epoxy between the layers and clamping with wedges between a precut 2x6 and the skin surface.
Jeff Hunt
1st Lieutenant
Great reporting Andy. Super informative and kudos to everyone else for their informative posts.
Jeff
Jeff
fubar57
General
Great stuff. A wee bit more finicky than replacing metal panels
