BD-4 CAD Drawings

This is a listing of CAD drawings sent in by builders. We know that there are some more, if you come across them please send us a note and we will provide them here.

File Description Image Drawings of all gussets. Created by Bob White.

From: Bob White
Date: Sun, 22 Feb 2004
The latest version of the DXF files have all been printed and compared to the originals in the book and are very close. I'm claiming all intersections and holes are within .032" of the originals or better. Most of them are within the line width. The lastest file name is and should be dated Sep 20, 2003 or later. It is about 150K in size. I would appreciate it if someone would print them out and compare them independently.

It seems to me that if the angles and gussets can both be cut from drawings, most of the variation in construction could be mitigated. If the fuselage was drawn and assembled in a 3D CAD package, the first metal should be pretty close. It's probably as much work to do the CAD assembly as it is to do a real fuselage, but a little cleaner. :)

Bob White
al_sheet1-2.dxf The basic pieces needed for the fuselage, laid out on a 48 X 144" 0.063" 2024 T3 aluminum sheet.

Since laying out this sheet, I have learned a little more about bending aluminum.  The bending allowance for a 1/4" radius bend in 0.063" aluminum is 0.186".  For a 3/8".  For a 3/8" radius bend, the bending allowance is 0.240".  So for 1/4" radius bends on a 1X1 angle, should be 2 - 0.186 = 1.814 or about 1 13/16.  For a 3/8" radius, 1.760 or a little over 1 3/4".  Please adjust accordingly.
Reference:  "How to Do Aircraft Sheet Metal Work" by Norcross and Quinn, 1942, pp 95
sk21-rib.dxf  A drawing of a rib panel. Based on drawing SK-21 "PANEL RIB (ALUMINUM)" overlaid over the 64-415 airfoil coordinates. Dimensions are good to approx. +/- .022", airfoil is drawn on outside edge of ink line and within +/- .006". (This amount of error only at the leading edge due to length of line segments used. Much closer elsewhere).
panel.dxf Drawing of the instrument panel (to plan the instrumentation).
v6cowling.dxf Shows a Ford V6 engine and a Blanton PSRU in a stock BD-4 cowling.
enginemountbracket.3dm Not a CAD drawing, but a Rhino file; here a PDF printout with a photo of the finished part (sans hole). With that you could order it from a local shop.
n239cp.3dm Rhino 3D model (for questions ask Holger)
airfoil_good_one_honeycomb_rib.dwg This autocad drawign for a honeycomb rib was provided by Louis Bigelow
airfoil_good_one_honeycomb_rib.dxf DXF file for the honeycomb rib. There are sometimes problems with dxf conversions so check against the plans before relying on this file.