How's my math? And scratchbuilding a 1/350 helicopter?

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willshak - 07 May 2006 14:58 GMT

1. I have a 1/350 scale model USN Cruiser. I want to scratch build a
1/350 Piasecki HUP-2 helicopter, circa late 1950s, to sit on the back of
the ship (I don't really want to scratch build it, but there is no 1/350
scale HUP-2 out there).
The actual ship is 717' long. The ship model is just a hair over 24-1/2"
long. At 1/350 scale, that's about right.
The HUP-2 was 32' long, which works out to 1.097 inches, or 1-3/32" in
1/350 scale, correct?.
If correct, we'll just round it off to 1-1/8"

2. What would be a good medium to create this helicopter body? At this
size, it would have to be something that would produce a smooth finish
when filed to shape and sanded. I intend to use some PE scraps (sprues)
for the rotor blades and some thin music wire for the wheel struts. All
clear side windows will be painted black. I don't know what to use for
the clear bubble on the front. Maybe some acrylic gel like Liquitex.
I suppose I could get some generic 1/350 USN aircraft decals for it.

Any suggestions?

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Bill
In Hamptonburgh, NY
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frank - 07 May 2006 19:43 GMT

How about Plexiglass or Lexan or Acrylic? In that size, it shouldn't be
too hard to work with & then you could just polish out the clear bubble.

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willshak - 07 May 2006 23:21 GMT

> How about Plexiglass or Lexan or Acrylic? In that size, it shouldn't be
> too hard to work with & then you could just polish out the clear bubble.

That sounds good, and I do have some 1/4" acrylic sheet laying around.
1/4" works out to 7.3 feet in 1/350 scale so it is more than thick
enough. If it works out and looks good, I'll post some finished pics
over in a.b.m.s. If it doesn't look good, I'll say I never made it. :-)
Thanks..

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Bill
In Hamptonburgh, NY
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Kurt Laughlin - 07 May 2006 20:23 GMT

> 1. I have a 1/350 scale model USN Cruiser. I want to scratch build a 1/350
> Piasecki HUP-2 helicopter, circa late 1950s, to sit on the back of the
> ship . . . The HUP-2 was 32' long, which works out to 1.097 inches, or
> 1-3/32" in 1/350 scale, correct?.

A little longer than 1-3/32, but yes, your math is right. Why use 1-1/8?

> 2. What would be a good medium to create this helicopter body? At this
> size, it would have to be something that would produce a smooth finish
[quoted text clipped - 3 lines]
> clear bubble on the front. Maybe some acrylic gel like Liquitex.
> I suppose I could get some generic 1/350 USN aircraft decals for it.

The width was what, 8 feet or less? I would laminate some 1/8 thick
Evergreen sheet rectangles together, cut out the profile with saws and
files, then sand/file the fuselage shape. (This is what I did to make a
1/350 SS-1 HOLLAND VI submarine.) You could cut a notch at the front and
glue in a piece of acrylic and sand to shape for the cockpit. You could
probably get passable landing gear and rotors from other 1/350 helo kits and
PE frets.

KL

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Greg - 07 May 2006 21:21 GMT

>The width was what, 8 feet or less? I would laminate some 1/8 thick
>Evergreen sheet rectangles together....

I second the acrylic suggestion.

I've whittle a lot of master parts out of acrylic and find it to be an
excellent choice. It is very hard and therefore holds sharp edges and
crisp detail much better than styrene. It polishes up crystal clear.
It is manufactured in thickness from 1/16" to two inches or more.

It is a little more difficult to work. You need sharp tools. You can't
carve it with a knife, but it saws, files and sands just fine. One
oddity is that you can GRIND it very well. It's melting point is much
higher than styrene and you can work it with power tools without fear.
You can do the rough shaping quickly with a bench grinder, die grinder
or even Dremmel. Use a coarse grind stone.

Conventional solvent based glues and putties do not work well. You are
best to work carefully and avoid having to use putty. You can solvent
weld it, but it requires really nasty stuff (MEK and EDC) so you are
better of just using super glue (also an acrylic).

I do not recomment laminating styrene sheet to get the reguired
thickness. It takes AGES for the solvent to work its way out of the
plastic to the point that it will not leave a witness line on the
exposed surface.

Greg Reynolds, IPMS

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willshak - 07 May 2006 23:34 GMT

>> The width was what, 8 feet or less? I would laminate some 1/8 thick
>> Evergreen sheet rectangles together....
[quoted text clipped - 26 lines]
> Greg Reynolds, IPMS
>

Thanks. I've already considered Frank's acrylic suggestion. I have
pieces of 1/4" acrylic sheet laying around, which is more than thick
enough for the width of the helo, and all the mini tools necessary to do
some sawing, grinding, and filing.

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Bill
In Hamptonburgh, NY
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willshak - 07 May 2006 23:39 GMT

>
>> 1. I have a 1/350 scale model USN Cruiser. I want to scratch build a 1/350
[quoted text clipped - 5 lines]
> A little longer than 1-3/32, but yes, your math is right. Why use 1-1/8?
>

4/32" = 1/8". That will take care of the 'little longer'.

>
>> 2. What would be a good medium to create this helicopter body? At this
[quoted text clipped - 16 lines]
> KL
>

Frank's suggestion to use clear plastic sounds better, in that I can
paint everything except the cockpit and side windows, which will allow a
little light through the fuselage. I do have pieces of 1/4" clear
acrylic sheet laying around which will be more than thick enough. I
don't know the width of the helo, but it couldn't be more than 6 feet,
and possibly only 5 feet wide, at least from what photos I have seen.
1/4" works out to 7.3 feet in 1/250 scale, so it is more than thick enough.
I don't have any other 1/350 helos and wouldn't want to buy one just for
the struts and wheels. I have enough PE sprues to make more than 6
blades. At this scale, how much detail can be shown anyway?
The only problem I foresee is with my clumsy hands, and maybe decals.
Thanks.

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Bill
In Hamptonburgh, NY
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willshak - 08 May 2006 00:37 GMT

>>
>>> 1. I have a 1/350 scale model USN Cruiser. I want to scratch build a
[quoted text clipped - 34 lines]
> and possibly only 5 feet wide, at least from what photos I have seen.
> 1/4" works out to 7.3 feet in 1/250 scale,

Typo: I meant 1/350 scale, not 1/250 as above.

> so it is more than thick enough.
> I don't have any other 1/350 helos and wouldn't want to buy one just
[quoted text clipped - 4 lines]
>>
>>

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Bill
In Hamptonburgh, NY
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Charles Metz - 08 May 2006 21:31 GMT

> 1. I have a 1/350 scale model USN Cruiser. I want to scratch build a
> 1/350 Piasecki HUP-2 helicopter, circa late 1950s, to sit on the back of
[quoted text clipped - 5 lines]
> 1/350 scale, correct?.
> If correct, we'll just round it off to 1-1/8"

--snip--

Your calculations are correct -- and 1-1/8" (1.125") should be close
enough, since the discrepancy would correspond to an excess of only 9.8"
in length on the real aircraft.

Charles Metz

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Model Forum / General / Models / May 2006

How's my math? And scratchbuilding a 1/350 helicopter?