Message 150, 14 December 2003
Hi all,
Today I took a closer look at the Sierra custom fit HGU-2A/P that I received two weeks
ago. Under one of the earpads I found the label below.
I would have loved if it had said Protection Inc. but no such luck. It seems that my
imaginary link between Sierra Engineering and Protection Inc. is becoming weaker.
Cheers, Bluelight
Label from custom fit Sierra HGU-2A/P with one-piece
ramshorn visor
Message 92, 1 December 2003
Hi all,
I made a mistake in my last posting on this topic when I claimed that both Figmo and
Bloodhound aired the view that their mystery helmets were early HGU-33s. Figmo actually
said: "the helmet is transitional ie this ain't no APH-6 and not a PRK-37/P. I think
this helmet is a prototype developed by Sierra Engineering" (cut and paste from two
messages). Bloodhound bought his yellow helmet from Paul Taylor and both of them
identified the shell as an early HGU-33 and not an APH-6.
The helmet is not necessarily a prototype since Sierra offered it for sale in their 1973
catalogue (at least three examples survive; Bloodhound's, Figmo's, and allegedly Pete
Olsen also has one). If Figmo, Bloodhound and Paul Taylor all are right the helmet shell
should be a precursor to the Gentex DH-151 shell which was later standardised as PRK-37/P
and used for HGU-33/P, HGU-34/P and a whole host of other US Navy helmet configurations.
Thus the question about connections between Gentex, Protection and Sierra remains.
Cheers,
Bluelight
Message 66, 27 November 2003
Hi Bloodhound,
Funny that you should bring up this topic. Lately I have been trying to find more
information about the major industrial players in US flying helmet development and
production, Gentex, Protection Inc, Sierra, and Scott, and MSA is also there somewhere. I
am specifically interested in the buy-outs and takeovers including timelines because it
also defines transfer of technology and copyright.
The reason for my interest right now is that I am still struggling with Figmo's blue
"mystery" helmet and your yellow VF-142 helmet, both of which have the modified
APH-6 type oxygen mask receivers with a hinged centrebox. When we last discussed these
helmets you and Figmo both aired the opinion that they were early HGU-33 helmets rather
than APH-6 derivatives. My problem is that the DH-151 helmet shell, which was later
standardised as PRK-37/P and used for HGU-33/34 and other US Navy helmets, appears to be a
Gentex design. Figmo's and your helmets, however, were made by Sierra Engineering as
evidenced by the Sierra Engineering 1973 catalogue. I have included a number of pictures
that illustrate my points.
As we discussed earlier there are two versions of the bayonet receivers, the ones that are
on your helmet and the ones that you have in the Sierra p/n 345-315 retrofit kit. As you
can see from the pictures your and Figmo's helmets are identical to the one shown in the
Sierra catalogue. The probability of your helmets being Gentex DH-151 shells modifed with
a Sierra retrofit kit is therefore very low.
I have a theory that the DH-151 might originally be a Protection Inc design that Gentex
took over when they bought PI, but I still need to find a link between Protection Inc and
Sierra before I would find it likely that your helmets have shells made to the same specs
as the DH-151.
Cheers, Bluelight
Message 50, 23 November 2003
Hi Bluelight,
For once, I will plead ignorance (yeah, I know....treasure the moment) of the exact
interaction and time-lines between Sierra, Scott, Gentex, and protection Inc.
interactions. The only thing I am sure of (I think), aside from the fact that Scott took
over Sierra Engineering and Protection Inc. went to Gentex, is that I am unsure of the
specifics associated with all this. I know that Sierra offered its custom fit helmets in
the late 60s (as you remark upon), which suggests a strong Protection Inc. link (due to
the fact that the Sierra custom fit package is closely based on the TopTex features
originated by PI). Gentex appears to have bought the former Sierra operation from Scott,
after that takeover and PI as well, since they seem to all have ended up under Gentex's
control...until the whole custom fit operation went to Flight Suits Limited (originally a
branch of Gentex?). That custom Gentex helmet you showed us pictures of is remarkably like
the counterpart blue helmet, formerly worn by Grumman flight test pilot Tummillo, that you
mention I acquired on eBay.
I don't have any reliable answers here at all and perhaps we need some 'insider info' from
our contacts at Gentex. I'll plumb the depths and see what I can come up with. All of this
is, of course, absolutely fascinating, and it will be great to get some sort of precise
flow and chronology out of the matter, so that we can gain better understanding of exactly
what happened and when!
Cheers, Doc(as confused as the next guy)Boink
Message 34, 21 November 2003
Hi all,
There is a very interesting custom fit HGU-2A/P on eBay right now. It was custom fit by
Gentex in 1983 but it bears all the hallmarks of a Protection Inc. custom fit just like
the APH-6s and HGU-33s that we have seen before. The latest example was the light blue
APH-6 won by DocBoink some weeks ago. I have borrowed a couple of pictures from the
auction to illustrate my comments (see below)
The helmet is painted in the "standard" Protection Inc. paint with silver flakes
and it also has the chrome plated oxygen mask receivers (even if these pictures do not
show them to their advantage).
The edgerolls seem to be made with the same foam of questionable quality. Almost all of
these early custom fit helmets have collapsing edgerolls where the leather cover is
sagging. The same is true for the two early (1969) Sierra-made custom fit helmets in my
collection.
I seem to remember that one (or more) of you explained that Protection Inc. used to be
associated with Sierra and later, when Scott took over Sierra's oxygen related activities,
everything helmet, including Protection Inc. went to Gentex. Is my recollection of these
events correct, and if so, when did it happen?
Cheers,
Bluelight
Custom fit HGU-2A/P helmet used by "Dutch"
Riefler. © unknown
Message 3563, Jul 23, 2001
Hi Bluelight, Typical blue nylon US Navy style chin-strap and nape strap assemblies, such
as are found on the APH type (1960s) US Navy helmets. The leather interior and leather
lined ear-cushions have the look of an early HGU-33/P type helmet, possibly? I'll defer to
others on this identification, but Sierra Engineering definitely offered custom fit
helmets and special one-offs as part of their routine line of services. They were one of
the most important Sierra Madre California based life support engineering firms for many
years, until finally undergoing the inevitable merging with larger companies much later
on. I am not sure who owns what they used to be (corporately speaking) now, but they were
unique innovators of much that was standard in the late 50s and 1960s and coordinated
development of many of the early critical aviation life support system components (such as
the MS22001 type positive pressure exhalation valve). They were also subcontractors and
major contractors for helmet and oxygen mask systems for decades.
Cheers, DocBoink
Message 3562, Jul 22, 2001
Hi all, Your help and suggestions are needed. What kind of helmet is this? In the sources
available to me it is just described as "Sierra Custom Fit". It was delivered as
a test specimen to the RDAF in the late 1960s when we were looking for a successor to the
P-4 helmet. The following points should be noted:
The helmet shell is prepared for one-piece ramshorn visor
It is custom fit (cast liner)
The leather edgeroll is stitched to the helmet shell
The chin strap has no studs. It cannot be opened without unscrewing its attachment screws.
It is only possible to adjust its length.
A small number of this helmet type were apparently test flown during 1968-69 but this
particular specimen was used for impact testing, hence the cracks between the chin strap
and the microphone plug. The cracks on the top of the helmet are not visible in these
photos. An interesting detail, by the way, is that of all the helmets tested the P-4 gave
the best protection against impacts from above but all the tested helmets were within
specifications.
Cheers, Bluelight
