How to Build a B-29
01-02-2016, 08:46 PM
#101
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Half-planked nacelle with the cowl off, showing the firewall and the "well nuts" Dwayne uses to control engine vibration between the firewall and the nacelle
Page from McMaster Carr catalog, showing how they work and so you can order some, if you want
Longitudinal splines for the nacelles, part of the kit wood, but NEVER used in a Dwayne bomber build. Looking back at the cowl-less nacelle, you can see areas o n the inside surface of the nacelle planking where he will glue extra layers of hard balsa to add strength, but NO longitudinal splines! He thinks they just add complexity, get in the way of tank and gear mounting and don't add that much strength. Certainly, the longevity of Dwayne's planes speaks to the science of that hypothesis
01-02-2016, 09:45 PM
#102
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Originally Posted by kram
Top half of all 4 nacelles planked with 1/8" hard balsa in about 1/2" strips. Dwayne estimates this took him about three hours total
That gives you some idea how fast he builds
That's fast!
01-04-2016, 03:48 PM
#103
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Next: planking the bottom half of nacelles, some of which will be gear-bay doors
Also a good time to lay inside double planking between the formers and outside the tank compartments: will add a lot of strength to the nacelles
01-05-2016, 07:38 PM
#104
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Bottom nacelle formers take some time to line up so planking will flow around the wheels and gear doors will look scale
I use two 1/8" balsa strips on the bottom centerline, so gear doors will be easy to part after the planking is finished. Only glue them together in the area where they won't be gear doors
The bulkhead just in front of the tires needs to be 1/8" aircraft ply, because it anchors the top of the gear door cylinders and will be the forward surface of the front gear door seam
01-05-2016, 07:40 PM
#105
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Bottom of outboard nacelles ready for planking
01-08-2016, 08:30 PM
#106
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Tedious little task of doubling nacelle wall thickness with 3/32" balsa planking on the inside, before finish planking bottom nacelles
Just like on the wing, carefully shaping the nacelle formers and dry-testing the planking ensures a smooth fit and none of that awkward sanding that leaves thin spots on the planking
01-08-2016, 08:33 PM
#107
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Bottom of Nacelle # 4 planked
01-08-2016, 08:40 PM
#108
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Carefully fitted 3/8" balsa blocks glued inside nacelles #2 and 3, where they will serve as gear doors' bases and hinge blocks
Bottom planking will be glued onto and outside of these 3/8" balsa blocks
01-08-2016, 08:49 PM
#109
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The two rear-most formers of nacelles #2 and 3 will be glued to a thin plywood base that 4-screws to the massive gear mounting plate
Thus forming an easily removable rear nacelle "shell" that will allow access to (and removal of) the main gear for servicing
01-09-2016, 09:24 PM
#110
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Planking the rear hatch part of nacelles #2 & 4
Note the little 1/4" ply plank that strengthens the base of the removable rear nacelle hatch, but doesn't cover the 6-32 screws that hold it to the wing
01-09-2016, 09:29 PM
#111
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Side view of #3 with gear doors cut off and rear hatch planked and slotted
01-09-2016, 09:34 PM
#112
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Perfecting the gear door openings:
I use two levels zip-tied together, do the openings at the same time
Straight edge then sits flat on all four gear hinge points, assuring symmetry and perfect door swing
Hinges will be Robart 1/8" with hinge pockets
Last edited by kram; 01-09-2016 at 10:03 PM.
01-09-2016, 09:41 PM
#113
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After planking: cut a slot for the gear strut, then dry-fit reassembly of the removable rear hatch
In some photos, gear has been removed to keep it from blocking our view.
Of course, when the rear nacelle hatch has been detached, this is really easy!
01-09-2016, 09:45 PM
#114
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Ventral view showing the 1/16" end caps on each gear door and the 1/64" temporary ply shims that will define our clearance gaps when they're removed
01-10-2016, 02:29 PM
#115
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Carefully measure center of doors before cutting them
01-10-2016, 02:32 PM
#116
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After cutting doors out, double-plank the inside for strength and rigidity
01-10-2016, 02:36 PM
#117
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Use a straight edge to line up all 12 gear door hinge locations
It is very important they be in a straight line fore-aft, also, or the door will bind
01-10-2016, 02:41 PM
#118
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Robart # 308 and #315
They're too long, so cut them and trim the burr carefully
I use epoxy for hinges and hinge pockets
01-10-2016, 02:44 PM
#119
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Use a homemade sanding tool to sand flat notches for hinge points
I use a 0.160" drill for the hinge pockets
Last edited by kram; 01-10-2016 at 02:49 PM.
01-10-2016, 02:47 PM
#120
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Cut slot for hinge pocket set screw so top of hinge pocket is flush with wood surface
Last edited by kram; 01-10-2016 at 02:50 PM.
01-10-2016, 03:11 PM
#121
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6 wheels
6 gear doors
2 gear door sequencers
brakes
Altogether add complexity to the build, but seem de rigueur for a decent scale B-29
01-11-2016, 08:15 AM
#122
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Awesome!
01-15-2016, 08:14 PM
#123
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Thanks!
Dwayne and I have both been working hard to pay for the hobby this week
More updates soon
Dwayne and I have both been working hard to pay for the hobby this week
More updates soon
01-19-2016, 07:18 AM
#124
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On the topic of Mindfullness and Meditation in Bomber Construction:
I spent some mental energy contemplating how to meld the fuselage to my (perfect) wing BEFORE I build it, so it doesn't become a snort-'n-root struggle to fit the two together AFTER I build it!
A little design and sequence planning I hope will save some sanding and grinding later
First: dry-fitting the wing saddles
01-19-2016, 07:21 AM
#125
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Layin' out the fuselage bones
