I an old retired guy in Northern California that somehow got interested in RC submarines. No background in subs as I was in the artillery. In any case I found David Merriam who sent me the links to his articles and suggested the 1/72 Mobius Skipjack. I ordered the hull kit, fittings kit, and a sub-driver. The hull kit and fittings have arrived and the sub-driver will arrive after Christmas. I have an engineering background and a fairly complete machine shop, small mill, lathe etc. I am 'handy". The hull sections are out of round, 90 degrees to each other. The forward sections are about three tenths of an inch wider than taller when put together, The aft sections are about four tenths of an inch taller than wider, in addition, the aft sections have a small vertical bow fore and aft which disappears when you compress the sections with your hands so they are round.
SO, I think I need to heat them so they fit better if I am to be able to make the hull joint work as shown in Davids manual.
I am not comfortable trying to heat and bend by hand so I think I need a jig.
David suggested the temperature to bend the plastic is about 230 degrees. I have an infra red thermometer and I can test using scrap plastic fins and rudder pieces. He also suggested spreading or compressing 20% more than the desired finished dimension.
Here's what I was thinking.
Looking at the hull halves
Front section needs to be compressed horizontally, Upper with pins, lower with holes., rear section needs to be spread horizontally.
I know how much for each at the hull opening.
Take a flat piece of plywood.
For the upper forward drill holes for the pins closest to the joint the proper amount to spread +20%
Mid set of pins prorate the amount to spread passed on distance forward
Front pin no change of course.
Put the forward upper hull half pins in the holes.
Heat to spec temp and let cool.
Put dowels in the holes on the board.
Put lower forward hull half on the dowels.
Heat to spec temp and let cool.
For the after halves drill appropriate hole pattern spreading the halves and do same routine.
Does anyone have experience making adjustments such as these? Thanks in advance.
I will probably build the Scamp as it was constructed at Mare Island and I am only 13 miles north.
SO, I think I need to heat them so they fit better if I am to be able to make the hull joint work as shown in Davids manual.
I am not comfortable trying to heat and bend by hand so I think I need a jig.
David suggested the temperature to bend the plastic is about 230 degrees. I have an infra red thermometer and I can test using scrap plastic fins and rudder pieces. He also suggested spreading or compressing 20% more than the desired finished dimension.
Here's what I was thinking.
Looking at the hull halves
Front section needs to be compressed horizontally, Upper with pins, lower with holes., rear section needs to be spread horizontally.
I know how much for each at the hull opening.
Take a flat piece of plywood.
For the upper forward drill holes for the pins closest to the joint the proper amount to spread +20%
Mid set of pins prorate the amount to spread passed on distance forward
Front pin no change of course.
Put the forward upper hull half pins in the holes.
Heat to spec temp and let cool.
Put dowels in the holes on the board.
Put lower forward hull half on the dowels.
Heat to spec temp and let cool.
For the after halves drill appropriate hole pattern spreading the halves and do same routine.
Does anyone have experience making adjustments such as these? Thanks in advance.
I will probably build the Scamp as it was constructed at Mare Island and I am only 13 miles north.
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