Message 3625, Jul 28, 2001
Hi Folks, I recently acquired a specimen of the Chinese TK-4A partial pressure helmet, along with its matching suit, the Chinese model DC-4. The suit is quite similar to the old USAF partial pressure suits used in the 50s and early 60s, having a capstan mechanical constriction operation. It resembles several other international versions of the subsequent production variants of the original 1946 Henry S-1 partial pressure suit design, that includes the Russian VVK-4, the Chinese DC-4, and several others. The Chinese TK-4 partial pressure helmet has been up until very recently something of an exotic and extremely hard to acquire item. Showing up rarely in the West, it has commanded prices from collectors varying from as much as US$ 4000 to as little as US$ 2000. As a result, it has been heretofore regarded as something of an enigma, with little being known about it.

Upon close examination, the Chinese TK-4A helmet shows that while it draws upon prior Russian pressure helmet technology, a few interesting and uniquely Chinese improvements to the basic engineering approach have been added. Unless one has a full three-view perspective of this helmet to base a first opinion on, it would appear from a frontal view only to be quite similar in external appearance to the US Air Force version of the Mk.IV type Navy pressure helmet of the early 60s, with a complexly curving clear external visor. However, it is very readily apparent that this helmet utilises an oronasal mask inside the pressure helmet itself--a feature that quickly sets it apart from Western full pressure or partial pressure helmets. Seen from the other views, it is also apparent that the TK-4A uses no swiveling (or fixed) neck ring, in the manner of the Russian GSH-6 series helmets. Further, the rear of the helmet is canted upwards, with a zippered entry into an OD external fabric (nylon) neck piece that is bonded to the inferior edge of the hardshell; inside this, there is a rubber neck dam that the head is inserted through (like the Russian GSH-6 helmets). Thus is bears some remote resemblance in its features to the 1960s Taylor and ML Aviation partial pressure helmets from the UK.
The inner oronasal oxygen mask cup is of the demand type and it entrains oxygen directly from a tube continuation of the oxygen hose that enter the front of the helmet on the left side. The mask is fastened to the wearer's face through use of an inner fabric helmet, utilising short straps on each side of the face that attach to hooks on the cup. Unlike the Russian and Western helmet systems in which the earphone system cushions are included as components of the inner cloth helmet, the TK-4A has earphone receivers are inset in cushions that are attached to the helmet's hardshell. The inner fabric mask serves only to hold the oronasal oxygen mask in position on the face, inside the helmet. Demisting of the clear external visor is accomplished through electrically heated filament strips bonded to the upper and lower interior of the visor glazing. An inner, articulated swiveling sun visor may be lowered across the eyes in much the same manner as that used in the Russian GSH-6 helmet, while pneumatic seal around the periphery of the clear visor inflates to seal the helmet when the visor is in the down and locked position. The helmet shell appears to be made of a smoothly finished plastic or fiberglass composite material painted white.
I have attached a few photos of the TK-4A, but have been as yet unable to take a more definitive series of images of it for your edification (that will follow in future). My understanding is that these and many other former government military items, may be purchased directly from the Chinese government in Beijing through a special outlet export store. However, with recent 'hardening' of official relations between the US and China following the EP-3 recon incident, it may become a bit more difficult to obtain items such as this in the immediate future. I have no clear idea as to what this assembly (the TK-4A helmet and DC-4 partial pressure suit set) may be obtained for in China (cost), but I acquired them new and unused for about US$ 700 from someone who had already imported them into the USA.
The Chinese TK-4A helmet and suit will be shown to better advantage after I have had a chance to take some photos of them. Thanks for bearing up under this extremely long email post. Any remaining questions about the Chinese TK-4A partial pressure helmet may be addressed to me, of course.
Cheers, DocBoink