Some of our BD-5 builders have received the first four packages, but have not started construction of their aircraft due to some parts being backordered. Although some parts are missing, the four packages contain enough materials to build the wings, vertical fin, rudder (minus the counterbalance and balsa tip which can be installed later) and fuselage shell.
The fuselage shell is probably the easiest to construct of all the major parts of the BD-5. The allowable tolerance of the over dimensions is such that the builder simply has to butt the sections together and drill them in. For those of you who wish to take the time and effort to device a method of checking waterlines, I have included the following dimensions:
Center forward tip of nose cone - WL 22.30
Center bottom seam at FU1, middle of flange - WL 13.75
Center bottom seam at FU6, middle of flange - WL 16.38
Aft bottom tip of fuselage - WL 20.92
Center of aft drive cone (where drive shaft exits fuselage) - WL 47.00
(Note: this is not the line of the driveshaft, but rather the point at which the drive line and WL 47.00 intersect.)
Please understand that these dimensions are nominal. That is, if everything is exactly perfect, including your workmanship and measurements, then your fuselage will indeed have these dimensions. In reality, your fuselage dimensions will vary somewhat from the nominal dimensions (as ours have) and should not be cause for alarm.
The most important aspect is to keep an accurate vertical centerline, so the fuselage will have no twist, and to keep the bottom seam straight so that fuselage will have as little curve left or right as possible. The exact length of each individual skin is relatively unimportant. If the right hand skins meet perfectly at WL 25.00 but the left hand skins have a gap of 1/16", or even 1/4", it will not affect the structural integrity of the aircraft as long as the rivets have the acceptable minimum edge distance (1.5" x diameter from center of rive to edge of material). This applies to all seams and splices on the aircraft fuselage, and they will all later be filled in with body filler to give the smoothest, most drag-free surface possible.
Following are some general tips that you might find helpful until you receive Supplement Materials Package 4:
Several layers of thinner gauge material can be used to make the FU13 belly doubler and clecoed in place. Later, when you receive the correct material (BD-5-M-0030) the thin material can be removed and replaced with .063" 2024-T3.
The pattern for part FU48 may not fit your airplane. It might be best to make a pattern from cardboard to fit your plane, then use it to make the metal part. Parts FU27 and FU28 will actually be approximately 1" shorter on the bottom than shown in Detail E, Page 411.
A plywood disc with a diameter of 5.97" should be used to replace FU66 until this part arrives. This is to ensure the proper circumference of the drive cone.
After a section of the fuselage is drilled and clecoed, a few rivets can be installed about every 4" to 6" along a splice. This will hold the parts in alignment and allow you to use clecoes elsewhere. The rivets can be removed later by placing a dull ice pick or similar tool in the center of the rivet head and striking sharply with a light hammer. This will remove the steel mandrel and allow you to drill through the rive with a No. 29 drill.
Now, a word about that wonderful stuff we have all come to know and love ... Pro Seal!
Some of our builders have cans of Pro Seal that carry expired dates printed on them. In most cases this will not present any problems. It simply means that the cure time could be longer or shorter than the specified 72 hours. Cure time can be shortened by the application of heat (no higher than 100°F) or an increase of 15% to 20% in the amount of catalyst used. The cure time may be lengthened by a small decrease in the amount of catalyst used or by lowering the temperature.
When opened, most cans of the white base compound will have a tough, dry surface. This should be peeled away and discarded. The rest of the white base compound should be smooth and free of lumps. Some separation may occur in the black catalyst during storage. This will show up as an oily residue on the surface and should be blended in with the rest of the catalyst. Any Pro Seal found to be unusable can be returned to Bede Aircraft for replacement.
Extra jars of the catalyst can be ordered from Bede Aircraft at $1.40 per jar. We are shipping two kinds of sealant (890 and 408). The catalyst for the 890 sealant cannot be used with the 408 base compound, and vice-versa, so be sure to specify the correct number when ordering extra catalyst.
If you have a problem with construction of a part, i.e. misdrilled hole, mislocated part, shy edge distance, feel free to write to me. I'll be glad to help you find a solution and publish an answer in this Bulletin to help other builders.
However, if your questions are about a deviation of design or modification to the design that you would like to make personally on your aircraft, my only reply will be "Don't do it!". We cannot and will not offer assistance to anyone making any changes to the BD-5 design, nor can we accept any responsibility for the consequences of such changes.
We are receiving many inquiries about optional equipment including avionics, lighting systems, and other equipment. Rather than try to answer each letter one at a time, I would appreciate it if you would hold these letters until you receive our optional equipment catalog. First copies should be ready for shipment by the end of this month.
I hope this Bulletin has been of some value to us both.
Frank Andrews, BD-5 Sales Manager
Last Update: 5/29/97
Web Author: Juan Jiménez
Copyright © 1997 by Juan Jiménez - ALL RIGHTS RESERVED