30 September 2015

HO3S-1 – Mach2 Model Kit Review

1. Introduction
Aircraft: Sikorsky HO3S-1
Model kit manufacturer / country: Mach2 / France
Scale: 1:72
Catalogue number: GP011
Release time: unknown

Basic information on the HO3S-1 helicopter is available in Wikipedia (link) and will not be repeated here.

2. Kit
2.1. Box
The box is a sturdy top-opener, 22 x 13 x 4 cm in size.

2.2. Instruction
Instruction is provided on one black & white A4 sheet. Typically for Mach2 kits, it gives a sketchy explanation of the building process and very little information on painting.

2.3. Plastic Parts
The kit contains two frames of light grey plastic parts. The quality of molding is poor, which is also, unfortunately, a trademark of Mach2 kits. Flash is abundant, and thickness of all plastic parts is excessive. Actually, the parts that are supposed to represent the cabin interior, landing gear, rotor head and rescue winch are so thick and so crudely detailed that the only way to obtain a realistically looking model would be to scratch-build all respective items, throwing the kit parts away.
The general shape of the kit appears to be more or less accurate. Accuracy issues include the following:
 - Unnecessary bulges on lower starboard and upper port side of the fuselage (a feature of Westland Dragonfly, not present on HO3S-1).
 - Inaccurate exhaust detail on fuselage port side (again, correct for Westland Dragonfly, not for HO3S-1).
 - Inaccurate panel lines on the main rotor pylon.
 - Grossly simplified and crude main rotor head.
 - Lack of distinctive stiffener plates on the tail rotor blades.
 - Excessive imitation of rivets on the fuselage (both sides) aft of the engine exhaust area. 
Basing on the reference data available from sources [1] and [2], it could be surmised that scalewise the kit is also acceptable. Here are some results of my measurements:
                              | Reference data    | Kit
Fuselage length       | 174mm               | 172mm
Tail rotor diameter    | 35.6mm              | 37mm
Main rotor diameter  | 203mm               | 194mm
Notable discrepancy in the main rotor diameter is most probably due to crude shape of the kit's main rotor head.

2.4. Clear Items
Unfortunately, clear plastic items are 1mm thick and not particularly transparent. Ensuring that the characteristic glass nose of the helicopter looks realistically would be a major undertaking.

3. Decal
There are two decal options provided:
A) U.S. Navy. BuNo unknown / UP32. Squadron HU-1. Early 1950s, off Korea.
B) French Naval Aviation (Aéronavale). BuNo unknown / 58S10. Squadron 58S (58 Escadrille de Servitude). 1952.

Variant A:
1) As can be seen from historical photographs, most HO3S-1 helicopters of the HU-1 had national insignia in 4 positions, whereas there are only 3 respective items on the decal. In any case, the national insignia decals are out of register (the red line not being centered on the white side bars) and therefore are only fit for a waste bin.
2) Available historical photographs indicate that HU-1 HO3S-1 helicopters adhered to the Navy's standard practice of placing a Model Name + Service Name + Bu No legend on the tail boom. There are no respective items in the kit's decal sheet.
3) The "Remove Chock" lettering on the decal is ridiculous. The correct text should have been, of course, "Remove Chute".
4) So far (as of September 2015) I was unable to find any historical photographs that would prove the existence of a HO3S-1 with the markings corresponding to those represented on the Mach2's decal sheet (UP32 code, checkered band and artwork).

What we see here is a decal that was apparently created basing on a drawing in a book (namely, USN / USMC Over Korea by Thomas E. Doll, Squadron / Signal Publications, 1988) and not on historical photographs.

Variant B:
National insignia and unit codes appear to be accurately represented on the decal.

4. Alternatives & Aftermarket
As of September 2015 there are no other model kits of this helicopter in production. In the past there have been kits made my Aerodrom (# EP-03) and MPM (# 72036 and 72126). Judging by available photographs, neither is significantly better then the Mach2's kit in terms of quality and detail. No aftermarket items are available either.

5. Conclusion
 - Acceptable overall accuracy.
 - Poor quality of molding, poor transparency of clear parts.
 - Minor accuracy issues – fuselage bulges; engine exhaust and air intake; panel lines.
 - Insufficient detail – cabin interior; landing gear; main rotor head; rescue winch.
 - Decals for the U.S. Navy option are out of register and inaccurate.
 - High price ($25 in 2013 at Hannants), considering the kit's size and quality.

As I see it, this kit could potentially be turned into an accurate model, but that would be a tremendous task requiring a lot of scratch-building. Advisable, therefore, only for those who are unable to live without an HO3S-1 in their collection. Others, I think, are better off waiting until this helicopter is kitted by some other manufacturer in a decent way.

6. Reference Data
[1] Basic information on the Sikorsky S-51 in Wikipedia: link
[2] Additional details on the S-51 and its derivatives: link
[3] Whirlybirds - U.S. Marine Helicopters in Korea | Lt.Col Ronald J. Brown | U.S. Marine Corps Historical Center, 2003 – available online here.
[4] Some notes outlining the S-51's service with the Aéronavale (in French): link
[5] Photo walk-around: link

PS: My advice is to be careful when looking at photo walk-arounds of museum exhibits: most of them are either USAF H-5's or Westland Dragonflies, and those have subtle yet visible differences when compared to the Navy / Marine HO3S-1 version.