Hi Everyone!
Hopefully someone with deep knowledge of Hipps/Anglin Kittens can help me with soem confusion.
I recently came into possession of a welded J3 Kitten fuselage along with a full set of blueprints from Anglin Special Aeroplanes printed in 1984, along with a partial set (wings only) from Hipps Superbirds printed in 1994.
Ive spent the past couple weeks pouring over the plans and now I'm ready to start construction on the wings. At least I was until I ran into some confusion between the plan sets.
Tucked into the stack of paperwork I got with the kit was a typed sheet of paper outlining changes that Hipps made to the Anglin design (I assume Hipps bought the rights to the design?)
One note on the paper, and reflected in the prints, is that Hipps uses a solid spruce spars whereas Anglin uses a typical spruce-capped plywood I-beam spar.
Everything I know about plywood I-beams (along with a small test spar I made) seems to indicate that when properly constructed, they are plenty strong for the application. A solid spar just seems like extra weight without added benefit. On the other hand, if the change was made for some particular reason, I don't have a problem spending the extra money on a nice piece of spruce spar stock if it means a safer airplane. But I'm leaning towards the plywood design.
Another note describes how the Anglin-designed ailerons with an aluminum trailing edge should be updated to the Hipps frise ailerons with a wooden trailing edge. I'll gladly take frise ailerons, the the problem is both designs seem to have the same overall geometry and hinge position so I'm not sure how the Hipps changes things for the better.
Thirdly, the ribs on the Anglin plans are slotted cap strips with the diagonal members glued in to the slots, while the Hipps design is solid cap strips with the diagonal members glued on along with rounded plywood gussets. I lean towards the later design with gussets but again, looking for guidance on why this change was made.
Thanks in advance for any advice or opinions !
Hopefully someone with deep knowledge of Hipps/Anglin Kittens can help me with soem confusion.
I recently came into possession of a welded J3 Kitten fuselage along with a full set of blueprints from Anglin Special Aeroplanes printed in 1984, along with a partial set (wings only) from Hipps Superbirds printed in 1994.
Ive spent the past couple weeks pouring over the plans and now I'm ready to start construction on the wings. At least I was until I ran into some confusion between the plan sets.
Tucked into the stack of paperwork I got with the kit was a typed sheet of paper outlining changes that Hipps made to the Anglin design (I assume Hipps bought the rights to the design?)
One note on the paper, and reflected in the prints, is that Hipps uses a solid spruce spars whereas Anglin uses a typical spruce-capped plywood I-beam spar.
Everything I know about plywood I-beams (along with a small test spar I made) seems to indicate that when properly constructed, they are plenty strong for the application. A solid spar just seems like extra weight without added benefit. On the other hand, if the change was made for some particular reason, I don't have a problem spending the extra money on a nice piece of spruce spar stock if it means a safer airplane. But I'm leaning towards the plywood design.
Another note describes how the Anglin-designed ailerons with an aluminum trailing edge should be updated to the Hipps frise ailerons with a wooden trailing edge. I'll gladly take frise ailerons, the the problem is both designs seem to have the same overall geometry and hinge position so I'm not sure how the Hipps changes things for the better.
Thirdly, the ribs on the Anglin plans are slotted cap strips with the diagonal members glued in to the slots, while the Hipps design is solid cap strips with the diagonal members glued on along with rounded plywood gussets. I lean towards the later design with gussets but again, looking for guidance on why this change was made.
Thanks in advance for any advice or opinions !
