Akihiro Danjo’s VP Mechanism for F1M and F1D

In Uncategorized on August 19, 2019 by nicholasandrewray

Akihiro Danjo’s VP Mechanism for F1M and F1D

VPF1MF1D copy1

VPF1MF1D copy2

Click here to download a PDF of the plan.


Construction Photo Essay:

Drive arms and stop arm are made from a single piece of 0.011” music wire for F1M and .008” for F1D.


The shaft is inserted though the arms. The shaft diameter is 0.013” to .015” for F1M and .012” for F1D.


Tape the arms and a shaft on this jig to set 45 and 90 angles.


I use Stay Brite though any solder will be OK.


The main body is 2mm thick #10-12 balsa, 3mm tapered to 2mm for F1M. Lighter wood and 2x2mm for F1D. I use total eight figure ‘8’ hinges for F1M and four figure ‘8’ hinges for F1D.


I use Kevlar thread for hinges. Kevlar thread is untwisted to get suitable strands.


Kinoshita-san uses silk thread for F1D, but I use Kevlar for F1D too.


A socket filler is used for F1M only and it is 2.0mm dia by 8mm long balsa.


Shaft bearing is cut from stainless steel tube. HTX-23-6TW (.025”od x .017”id) for F1M.



The Drive pin is 0.011” wire for F1M and .008” wire for F1D.
Drive pin for F1M is short and straight. It is inserted (pushed) into the socket tube and the filler and then CyA glued.
Drive pin for F1D is ‘?’shape and is glued to outside of the socket tube (therefore there is no filler for F1D).


Spring supports are 2x2mm #10 balsa for F1M and a little lighter balsa for F1D.
This is an extra short spring, so the supports are not a triangle but just a small block.


Stopper screws are nylon #0-80 x1/8” for F1M and 00-90 for F1D.
Screw holders are #10-12 balsa. I don’t use a tap for threading. Just only screw a nylon screw into the prepared hole. Sometimes very thin glue is used to harden the thread.


Adjust the height of the screw holders and glue them on the main body.


If you need softer, thinner, spring for F1D, it will be better to join thinner, i.e .010”, wire together than using thinner than .012” wire for the shaft.



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