Introducing the pirouette FPV frame for GFPV

Signed-off-by: Arnaud Morin <arnaud.gfpv@mailops.fr>

spar.py

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+# @author Arnaud Morin <arnaud.gfpv@mailops.fr>
+# SPDX-License-Identifier: Apache-2.0
+# 
+import cadquery as cq
+
+from frame_params import (CF_DENSITY, FIT, TENON_L, THICKNESS, TBONE_D)
+
+# frame-wide facts -- hardcoded here to match frame_params' own values;
+# not linked by import any more, so keep them in step by hand
+MOTOR_GAP = 78.0        # motor-to-motor gap on a true X, same as the prop
+SPAR_H = 4.0            # the spar's own clear span
+SPAR_OFFSET = 2.5
+SPAR_TENON_POS = 9
+
+LAP_W = THICKNESS + FIT
+# How much len we add to add a crossing between lap
+# I choose to add twice the thickness
+LAP_OFFSET = 2.0 * THICKNESS
+
+# Spar len is motor gap + extra so two spar can cross and fit together
+# Extras are:
+# SPAR_OFFSET which is used to position the mortese in motor base
+# LAP_OFFSET to cross the two spar together
+SPAR_LEN = MOTOR_GAP + (SPAR_OFFSET + LAP_OFFSET) * 2
+# Motor axis
+MOTOR_CENTER = (SPAR_LEN - MOTOR_GAP) / 2.0
+# Tenon position
+TENON_CENTER = MOTOR_CENTER + SPAR_TENON_POS
+TENON_START = TENON_CENTER - TENON_L / 2.0
+TENON_END = TENON_CENTER + TENON_L / 2.0
+
+
+def spar():
+    part = (
+        cq.Workplane("XZ")
+        .polyline([
+            (0.0, 0.0),
+            (0.0, SPAR_H/2.0),
+            (TENON_START, SPAR_H/2),
+            (TENON_START, SPAR_H/2 + THICKNESS),
+            (TENON_END, SPAR_H/2 + THICKNESS),
+            (TENON_END, SPAR_H/2),
+            (SPAR_LEN - TENON_END, SPAR_H/2),
+            (SPAR_LEN - TENON_END, SPAR_H/2 + THICKNESS),
+            (SPAR_LEN - TENON_START, SPAR_H/2 + THICKNESS),
+            (SPAR_LEN - TENON_START, SPAR_H/2),
+            (SPAR_LEN, SPAR_H/2),
+            (SPAR_LEN, 0.0),
+        ])
+        .mirrorX()
+        .extrude(THICKNESS)
+    )
+
+    # Cut the overlaps: half-lap notches, centred LAP_OFFSET on each end
+    cut = (
+        cq.Workplane("XZ")
+        .polyline([
+            (LAP_OFFSET - LAP_W / 2.0, 0.0),
+            (LAP_OFFSET + LAP_W / 2.0, 0.0),
+            (LAP_OFFSET + LAP_W / 2.0, SPAR_H / 2.0),
+            (LAP_OFFSET - LAP_W / 2.0, SPAR_H / 2.0),
+        ])
+        .close()
+        .extrude(THICKNESS)
+    )
+    part = part.cut(cut)
+
+    # Second cut
+    cut = (
+        cq.Workplane("XZ")
+        .polyline([
+            (SPAR_LEN - LAP_OFFSET + LAP_W / 2.0, 0.0),
+            (SPAR_LEN - LAP_OFFSET - LAP_W / 2.0, 0.0),
+            (SPAR_LEN - LAP_OFFSET - LAP_W / 2.0, SPAR_H / 2.0),
+            (SPAR_LEN - LAP_OFFSET + LAP_W / 2.0, SPAR_H / 2.0),
+        ])
+        .close()
+        .extrude(THICKNESS)
+    )
+    part = part.cut(cut)
+
+    # T-Bones on tenons (x, z)
+    tbones = [
+        # First tenon (upper left)
+        (TENON_START - TBONE_D/2 + 0.05, SPAR_H/2),
+        (TENON_END + TBONE_D/2 - 0.05, SPAR_H/2),
+        # lower left
+        (TENON_START - TBONE_D/2 + 0.05, -SPAR_H/2),
+        (TENON_END + TBONE_D/2 - 0.05, -SPAR_H/2),
+        # upper right
+        (SPAR_LEN - TENON_START + TBONE_D/2 - 0.05, SPAR_H/2),
+        (SPAR_LEN - TENON_END - TBONE_D/2 + 0.05, SPAR_H/2),
+        # lower right
+        (SPAR_LEN - TENON_START + TBONE_D/2 - 0.05, - SPAR_H/2),
+        (SPAR_LEN - TENON_END - TBONE_D/2 + 0.05, - SPAR_H/2),
+    ]
+
+    # Cut the T-Bones
+    cut = cq.Workplane("XZ")
+    for x, z in tbones:
+        cut = cut.moveTo(x, z).circle(TBONE_D/2.0)
+    part = part.cut(cut.extrude(THICKNESS))
+
+    # Center the part
+    part = part.translate((-SPAR_LEN / 2.0, THICKNESS / 2.0, 0.0))
+
+    return part
+
+
+result = spar()
+
+assert result.solids().size() == 1, "spar is not one solid"
+
+# Mass report
+def report():
+    vol = result.val().Volume()
+    print(f" Mass    = {vol * CF_DENSITY:5.2f} g")
+    print(f" Mass x4 = {4 * vol * CF_DENSITY:5.2f} g")
+
+# Running outside CQ-editor
+if "show_object" not in globals():
+    def show_object(*args, **kwargs):
+        pass
+
+show_object(result)
+
+if __name__ == "__main__":
+    report()