Primary stringers being run on the right side (above left) of the fuselage. Once he’s finished with these, Pat will unpin the fuselage and flip it over to gain access to the left side, and repeat the stringer process. The fuselage, unpinned
the round” like Pat did with his Beriev. However, wherever possible, I prefer build- ing off a horizontal keel rather than the ver- tical. If like me you have been trained since birth to build off the vertical keel, it will feel odd at first; but to my mind, this now makes more sense in many situations, when typi- cally the thing we struggle with the most is maintaining the symmetry of the fuselage in plan view.
Regardless of your preference, note that you could tack glue your crosspieces to the keel right at the edge of each former position and use them to help precisely align the for- mers, ensuring that they are square to the plan centerline if you’re building off the hor- izontal keel or, if you are building off the vertical keel, that correct vertical alignment is maintained. In either case, the trick is to always set the crosspiece on the narrowest keel side of the former, so the former doesn’t get pinched as you’re trying to fit it into place.
You don’t have to use the crosspieces in this way. Buzz positions his formers accord- ing to the plan, and Pat according to regis- tration marks he puts on the keel pieces. In both these cases the crosspieces are set more or less at random in between the formers. Use the method that works best for you!
from the building jig (above right) and taking shape. Due to the thickness of the foam, at some point it will be necessary to remove the crosspieces to complete the required stringer work.
Note also that when building “in the round” with full formers, you will sometimes find you just cannot fit a full former into po- sition at all, because the space between the keels is too confined. In this event, you may have to split the former to get it on the keel (this is not an issue with the method out- lined on the Rocky Top site).
Once all the stringers and whatnot have been run, the potential benefits of using a building jig continue. You can leave the fuselage in the box for much of your finish sanding, a real boon to us brutish, ham-fist- ed folks who cringe at the very thought of handling a delicate structure as we work it over with a 220-grit sandpaper block. You might even find that, with the box absorbing more handling than the struc- ture, you can start to build with lighter wood, or design lighter structure in the first place. Hmm, now we’re getting somewhere! Lighter structure equals longer flights. And with a little thought, you could easily modi- fy a building jig to serve as an alignment aide for setting wing and tail incidences and gluing everything up during final assembly. Working with a Styrofoam box would make this a snap. You could use a ruler, try square, or computer graphic printout to mark out the positions on both sides of the
box and, making sure the two sides are identical, cut into the box sides with a utili- ty knife to make a temporary support sad- dle for the wing/stab. Minor adjustments to the alignment would be easy to do with a sanding block. You are limited only by your willingness to try something new. But in truth, the best part of all about us- ing a fuselage building jig is the moment when you decide you have pushed its useful- ness to the maximum. Off come the straps, away falls the box, off comes the foam or bal- sa crosspieces, and the caterpillar emerges from its chrysalis as a fully formed thing of beauty, maybe lighter and better aligned than anything you have ever built before. Sounds good, huh?
And believe me that is nothing compared to the relief you will feel when you are out at the field for the first time test flying your new baby, and things aren’t going well, and you know you can just eliminate a banana twist fuselage (nothing worse) from the list of possible culprits right then and there. Freeflight is hard enough already; who needs that kind of subversion of our noble purpose? I maintain that we need all the positive support we can muster as we doggedly, diligently pursue the elevation of our craft.
Crosspieces removed, more stringers added (above left), ready for the application of sub-assemblies and finish sanding. A shot of the completed
FLYING MODELS
Beriev BE-12 (above right). Now that’s something you don’t see every day at the field! Besides being a gorgeous model, it’s a fine flyer, too.
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