Message 3550, Jul 22, 2001
As promised I hereby post a photo of a Danish P-4 helmet with clear visor as used by police observers. The green badge on the helmet is the Royal Danish Police badge. The clear visor is a modified HGU-26 visor where the knob has been cut off. A neoprene list has been glued to the upper rim in order to make the visor edge thick enough for the P-4 visor yoke to get a proper grip. The black neoprene is visible in the visor yoke slot.
Cheers,
Bluelight

Message 3503, Jul 20, 2001
Interesting information on the visors, Bluelight. Will look forward to some photographs when circumstances and time constraints permit. Welcome back from holiday!
Cheers, DocBoink

Message 3492, Jul 19, 2001
Hi DocBoink, Maggot et al, The clear visors used in Denmark were modified HGU-visors. Additional material had to be glued to the top edge of the visor, otherwise the visor yoke could not hold on to the visor glass. I will post a picture once I have everything sorted out from my Denmark-trip.
Cheers, Bluelight

Message 3490, Jul 19, 2001
Hi Maggot, I took the same sort of hard look at that P-helmet and its strange visor. You may in fact be correct in stating that it APPEARS as if someone took an HGU or APH-type clear visor and jury-rigged it to the P-helmet's visor yoke. It would serve as a bird strike visor, but the angulation from brow of helmet to bridge of nose is all wrong (further evidence that this is a later helmet visor, rather than something that was originally intended to go with a P-series helmet). Cheers, DocBoink

Message 3489, Jul 18, 2001
I'd have sworn that's a tacked on APH-5 or HGU-2 clear visor (if there was such an animal) - am I seeing things or does it look like there's a "tooth" on the clear visor in the side view of the helmet? It also has a decidedly "hacked" look from the side view - visor cou\ntour completely different than what one would expect from a clear "P" helmet visor...
Maggot

Message 3487, Jul 18, 2001
Hi, I think the helmet is a nice complete P 4 type, and the clear lens is the original one used during night flight to avoid severe occurrence in case of bird strike, I have one of this lens with the USAF spec. number similar to that assigned to the normal type.
best regard, Horrido

Message 3465, Jul 17, 2001
Hi Pilot, Looks pretty OK to me. The only "funny" thing is the clear visor as these helmets always were fitted with a dark visor.
The Royal Danish Air Force used a similar modification for police observers who predominantly participated in low-level flights. Due to the bird strike risk all Danish pilots and crew members must wear a visor at all times. For fighters we had introduced double-visor helmets but for budgetary reasons other flying personnel used the old P-4 helmets. The P-4 could only take one visor but a dark visor would be a pain for low-level work especially in Denmark with its often cloudy or rainy weather, so the solution was a clear visor plus a pair of HGU-4/P sunglasses.
In conclusion, the helmet is not as originally issued but may very well be service original.
Cheers, Bluelight
--- In flightgear@y..., Pilot <pilot@u...> wrote:
eBay item 1167833730 (a P-4 helmet with clear visor); A very nice looking helmet...could anyone tell me if it is a fair example of the helmet and do the components look   authenthic. I know almost nothing about the early examples of flight helmets.
Pilot

Message 3020, Jun 19, 2001
Hi Maggot, I'll have to go along with Rich on this and opt for the lower spring. Although, as has been pointed out, when the springs are attached (and stretched out a bit), the "resting" unloaded length becomes sort of academic. The attachment loops on the end are different from the original, but they could probably be 'teased' a bit into a somewhat more authentic shape (if one was that particular about it). Most of the springs in actual use acquired a patina of oxidation, but that could be induced by soaking them in water for a few days and letting them dry in direct sunlight. It's a close 'coil' between the two alternatives, however (heh-heh).
Cheers, DocBoink

Message 3018, Jun 18, 2001
My opinion is the shorter looks a little more original - once they get stretched and hooked up, one has a hard time telling the difference. The one with the correct length (bottom) has a different shape to the hook end - more circular than a flattened oval.
Splitting hairs to the Nth degree, Maggot

Message 3014, Jun 18, 2001
I think the bottom spring would acquire the proper patina if left out in the weather a while! Much more convincing than the short one.
Rich

Message 3012, Jun 18, 2001
Here is what I have without too much digging: The middle spring is an original P-helmet visor frame type. The UPPER one was obtained through a local aircraft parts supply house (a couple years since I've been back there). The lower one... well, let's just say they're from another aircraft parts supply place ;-)
The upper one has the same crusty anodized look, but is a few turns shorter. The lower one is shiny new, same length, but a slight difference in the hook on each end.
Any thoughts? Maggot

Message 3004, Jun 18, 2001
Hi Maggot, Sounds like a plan. The local hardware stores carry a line of springs that come verrrrry close--but not close enough to pass undetected. The search continues, but meanwhile it would be good to see what you have there on that end, for a suggested comparison. Thanks.
Cheers, DocBoink

Message 3003,  Jun 18, 2001
I may still have a local aircraft hardware source which I have utilized for P-helmet replacement springs... they are not "bang on" but come pretty darn close - I have a hard time discerning them unless I have an original example sitting right next to it. will see if I can get some and we'll do a comparison here on site - you can tell me what you think.
Maggot

Message 3002, Jun 18, 2001
Ahahahahahahahahahahahahahahahaha! You spotted the springs! That is damned near amazing, Rich. I have to credit you with exceptional discriminatory abilities. You must have magnified the images and inspected that detail very closely, as probably only one or two others on the forum might have noted the fact that these are not originals (as you stated), but very near approximations. They are there only to maintain the visor in its retracted position until such time that I can find another original to mate up with the single original I have here.
Kudos to you for being Eagle-eyed (you definitely passed whatever test this might have been, but wasn't!). I'm posting this exchange on the forum, as it is a genuine credit to your discernment, vis-a-vis an eye for authenticity. We need more of this, I think, not less! There is a way to cast the rubber booties for the mic jack connectors, I am sure, but I have a few extra originals here, so that won't be a problem. I just haven't gotten to that part of the project yet, as with the nape strap, the wire loom, and the chin strap.
Cheers, Chris
----- Original Message -----
> Your P-4 looks good, but if you could locate a
> source for original visor springs that would be
> even better. It is interesting that only the P-4
> (in my experience) used washers under the
> headphone assembly mounting screws.
> Rich

Message 2250, May 12, 2001
I found references to an interesting USAF Technical Report dated July 1953, titled "Windblast Visor for P-1 Helmet and A-13A Oxygen Masks" studies. I'll give you more information on this Tuesday, after I return. I expect it gives important background on developments that led to the use of the 'new' early style side-latch visor (such as Rich has on his "P-2"), and could be a most important recovery of information (if I can ever figure out how to locate it).
Cheers, DocBoink

Message 2075, May 4, 2001
Bones, I bet that film you refer to is one and the same that Rich mentioned he had seen. More evidence stacks up on the interesting history of the P-1 helmet, eh? Thanks for these additional recollections and information!
Cheers, DocBoink

Message 2044, May 1, 2001
Bones, you are indeed a true devotee of this flightgear biz. Your sainted wife has my most sincere sympathies, of course, but this is HOT STUFF! My own sainted wife (Saint Irene, by name) is also quite familiar with that crazed look and fevered brow you reference, heh-heh). A little catalyst now and then appears to be good, in terms of stimulating parallel thoughts that may produce yet another gem of information, drawn out from its dim cavern of shaded recollection! Go with it! (And please keep us apprised!).
Cheers, DocBoink

Message 2043, May 1, 2001
Greetings all
DocBoink you have done it again!!!. Fantastic info. It has stirred a memory in me, and has pushed me to a new fury of insanity. I HAVE SEEN THAT VISOR SOMEWHERE!!! Operationally.
I cannot remember where, but I will look. Kathy has that look, like she wants to go hide, when I go manic like this looking for something. Keep up the great work
Bones

Message 2035, Apr 30, 2001
Bluelight,
As regards the perforated visor yoke that you reference, I too was puzzled by this until I rechecked all the early TO illustrations for P-1A through P-3. [As Steve has pointed out, these were graciously 'loaned' to me, so I am really not at liberty to distribute them (pending his approval & consequent completion of the book he is preparing on these matters), however, the more eyes that scan them in theory, the better our assessments would be of precisely defining and redefining their mandates]. What I found was that all the early TO illustrations show this same perforated outer visor yoke bar in use.
This was also confirmed by Rich yesterday, after he spotted the scanned image I posted from a TO and mentioned the fact that a very early Air Force training film he has (early 50s), showing USAF F-86D pilots in their contemporary flight gear, also clearly showed them with this perforated visor yoke on their helmets. This was a welcome additional verification of this very early visor mounting system.
I cannot figure out what the purpose of the drilling out of this piece would be, unless it were a somewhat more hopeful than functional weight reduction scheme. Apparently, however, it lost out to the solid aluminium outer yoke that we are familiar with at a fairly early date. As to whether or not it made it to Denmark (or Yugoslavia, or any other NATO nation) is a question I have no answer to.
Cheers, DocBoink

Message 2027, Apr 30, 2001
Hi DocBoink,
Thank you for your very elaborate insight into the P-helmet visor question. We can always trust you to provide the longest postings on flightgear. Luckily, as it turns out they are also some of the most interesting, to me at least.
I am left with two questions after your two visor postings. Firstly; does any of you have an example of the perforated visor yoke shown in the scannings from the T.O.? The visor yoke on Rich's "P-2" is made out of solid aluminium as far I can see. (I take it that you did not add the holes yourself, Doc, as they were not in blue?).
Secondly; what kind of information might pop up from the P-series helmet T.O.s if a fresh pair of eyes were to peruse them? I would humbly volunteer to give it a go if you would provide me with photocopies of the relevant T.O.s (this is of course a sincere offer in the interest of science - not a shrewd attempt to lay my mitts on a number of T.O. for my personal collection).
Cheers, Bluelight

Message 2025, Apr 30, 2001
Gentlemen:
One last bit of additional information, specific to the previous email message dated earlier today (29 Apr 01) and also to an original question posed by Bluelight, follows.
There were (at least) two different sets of helmet pivot-pin plates used on the P-series helmets, for visor mounting purposes: an original set, designed with a pin on the uppermost part of the plate to act as a retracted visor yoke stop and specific to use with the "Early Visor, Type Original", and a later set, essentially identical in almost every respect to the former, but without the upper protruding pin. These two set of plates were TO'd roughly in 1951 and 1956. The PNs for the original pivot-pin plates were PN 51C3634R (right side), and PN 51C3634L (left side). The PNs for the latter set of pivot-pin plates were PN 56C3511R (right side), and PN 56C3511L (left side).
The fact that all early P-series helmets (P-1 through P-3) had these plates exchanged when the new TO mandated them was distributed probably accounts for the fact that so few helmets are found today with the original type pivot-pin plates still attached. Rich May's "P-2" helmet would appear to have one of these extremely rare surviving examples of the early visor mounting plates.
Cheers, DocBoink

Message 2018, Apr 29, 2001
Gentlemen,
I am sure you all have moments, late at night, when the proverbial light bulb flashes on in one's cerebral cortex, as a truly GREAT realisation comes into sharp and exciting focus. Sometimes this takes a more mundane form, such as a dawning awareness that that cute brunette you have always viewed wistfully from afar ACTUALLY likes you! At other times, it takes the upsetting form of an acute understanding that everything you formerly assumed true was wrong and an overall corrective reassessment is in order.
In this particular instance, the awareness that my theories on the evolution of the USAF P-series visors needed modification struck me at about 2AM, resulting in a definite lack of sleep as one idea piled into another with the rapidity of one AMTRAK train trying to simultaneously occupy the same space as another (coming from the opposing direction on the same set of rails).
The trigger for this flash of insight was a protracted conversation I had a few months ago with Rich Mays on certain aspects of his ostensible "P-2" helmet specimen. In discussing this endlessly fascinating conundrum, part of our exchange centered on the visor that his helmet had affixed to it. [As you will recall from several earlier discussions of this subject, an assumption had been made (on my part, admittedly) that the original hard external visor fitted to the early P-1A helmet had certain specific identifying characteristics that clearly identified it as being different from the later version. In conversations with Bluelight on the matter of visor nomenclature standards, it was suggested that this erstwhile "earliest" P-series visor (with prominent uppermost visor bar lift/grasp flange and short side-latching "J-arms") be uniformly referred to as "Early Visor, Type 1", whereas the subsequent (it was thought) "early" (or pre-centertrack), sidelatching visor (with longer "J-arms" and no top-mounted grasp/lift flange) be referred to as "Early Visor, Type 2" (the last visor version, used on P-4A and P-4B helmets was and will continue to be referred to as the "Centertrack Visor").] Rich's helmet, which appears to actually be an early 'Type 1' (the original USAF "Helmet, Flying, Protective Type 1", more commonly known as the "P-1") helmet fitted with a visor, has a head sling clearly machine-labeled "P-2". One of the theories involving this helmet of Rich's is that it is an original P-1 helmet that had had (for unknown reasons) a "P-2" head sling installed in it (the USAF P-2 helmet remains a semi-mythical beast, with only fleeting references to it in Wright-Patterson AFB aerolab technical literature and a few very poor photocopies of a two-part--soft inner and hard outer shell--assembly that is clearly labeled a "P-2 helmet" to document its existence). At any rate, in examining some images Rich provided of certain details of it, I noted what appeared to be a peculiar and previously unknown (to me) visor side-latch mechanism and helmet mount (rounded triangular pivot-pin plate, similar to those used on all P-series helmets for this hard external visor). My explanation of it was that this hitherto unknown side-latch and pin-plate assembly was a subsequent modification of the "Early Visor, Type 1" assembly, possibly a modification rendered with a hack-saw (to cut off part of the short-arm "J" catch mechanism), used with a pivot-pin plate that had had an additional pin added to it's uppermost edge for use with this particular bar. My inference was that this visor on Rich's helmet was an experimental 'one-off' attempt to improve the plainly less-than-ideal early side-latch visor mechanism's functioning.
OK, cut to the chase.... Yesterday, I was perusing the stack of early P-series Technical Orders covering this early class of USAF helmet (TO 13-1-37, later rescinded and redesignated TO 14P3-4-1) and ran across a picture of this 'one-off' visor bar mechanism (such as is installed on Rich's "P-2") right there in this early TO, clear as day. Further searching showed that this same "No-J-arm" side-latch mechanism appears in several different P-series TOs dated within the 1951 to 1952 period! Furthermore, the pivot-pin plate displayed in these TOs in use with the "No J-arm" visor side-latch bar is identical to that mounted on Rich's hypothetical "P-2" specimen.

Breakthrough! 1) My preliminary assumption on the original form of the P-series visor appeared to be all wrong and the erstwhile "Early Visor, Type 1" was not the original design, after all. The "No J-arm" side latch assembly, with its top pinned helmet mounting plates (as clearly installed on Rich's "P-2" example), seems now to have been the first and original hard external visor assembly (not the "Early Visor, Type 1"); 2) Rich therefore appears to have a helmet specimen that has the only surviving example I have seen to date of this ORIGINAL "No J-arm" visor design; 3) A redesignation of reference standard nomenclatural terms for describing these visor assemblies is definitely in order, resulting therefrom.
And so, thus somewhat humbled and contrite (no small order for DocBoink, who definitely doesn't like to feel contrite or humble), I offer up these revised terms which I would suggest we use to refer to the P-series visors (until the next startling bit of informational insight breakthrough changes these neat little assumptions again, eh?):

1) "Early Visor, Type Original" (describing the "No J-arm" side latch mechanism and corresponding top pivot-pinned helmet mounting plate, which were apparently the first to be used on any P-series helmet).

2) "Early Visor, Type 1" (describing the "Short J-arm" side latch mechanism and it's corresponding bottom pivot-pin helmet mounting plate as used with all subsequent visors, up through and including the last "centertrack visor" system).

3) "Early Visor, Type 2" (describing the "Long J-arm" side latch mechanism).

4) "Centertrack Visor" (initiated on P-4A type helmets and used up through the final P-4B variant of the P-series).

5) "Toptex Type Visor" (although not part of the P-series helmets as such, still worthy of inclusion in this reference nomenclature due to its importance as the only other USAF acceptable system in use by that service; this doesn't address or consider any USN or US Army variants).

Please refer to the poor but acceptable scan of the "Early Visor, Type Original", taken from USAF TO 13-1-37, dated 1951, for a diagram of this newly 'rediscovered' missing link in the hard P-series visor chronology to date.
Further notes: Again in deference to the usefulness of using a standard set of terms to refer to critical component items found on the P-series helmets, I would strongly suggest that the following terms found in the relevant USAF technical orders be adopted in our future discussions along these lines. These TO publications commonly refer to the P-series hard external visor bar as a "visor yoke" and the original leather oxygen mask attachments as "oxygen mask tabs". The P-type head suspension assembly is referred to collectively in the TOs as the "helmet headband" and "sling assembly", so "headband & sling" should suffice as a standard term of reference for our purposes.
Of additional interest is the fact that the early visor yoke (nee visor bar) for all P-series helmets consists of two-component aluminum bow-shaped ellipses--an inner piece and an outer piece. Whereas there was only a single standard size inner bow component for standard size early P-series helmets (small & large for P-1A/B types--the original P-1 was made in only one size), there were two differently sized outer bow pieces. This was intended to allow use of the regular three different sizes of hard visors (with the same basic yoke assembly). If you have an early P-series visor yoke whose inner and outer bow parts do not seem to fit together quite well enough, perhaps it is because someone inadvertently mismatched an incorrectly sized outer bow component to the inner bow. The yoke assembly PNs for the small size and large size P helmets were designated in the relevant TOs as Visor Assembly PN 51C3632-1 (consisting of inner yoke bow PN 51C3636 and outer yoke bow PN 51C3637) and Visor Assembly PN 51C3632-2 respectively. Visors (the shaded transparencies) themselves were specified in three distinct sizes, given as being PN 51D3643-1 Size Small, PN 51D3643-2 Size Medium, and PN 51D3643-3 Size Large. The TO this reference is taken from is TO 13-1-40, dated 1953, but in seeming support of the fact that USAF component upgrades and designations could be TERRIBLY confusing at times (even to the officials who issued and printed the TO specs), the same specifications for visors are rendered in reverse order in the later (updated) TO 14P3-4-1, dated 16 Aug 1957 (PN 51D3643-1 Size Large, PN 51D3643-2 Size Medium, and PN 51D3643-3 Size Small!). Much later, the visor yoke assembly was changed and redesignated (different from the original assembly specs--not the same as earlier type) for the "Centertrack Visor" as PN 56C3520-1 Visor Mechanism Small and PN 56C3520-2 Visor Mechanism Large.

One final additional observation on the early visor yoke "grab/lift" flange: The "Early Visor, Type Original" yoke had a flange that was attached to the yoke outer bow with two rivets. Only on the following "Early Visor, Type 1" yoke was this flange cast integrally with the aluminium outer yoke bow itself. On the final "Early Visor, Type 2", this grab/lift flange was eliminated altogether (or sawed off of the bow) to eliminate this protrusion as a potential source for parachute riser shroud-line fouling on high-speed egress.
In closing, as many of you know, recent months have seen the importation of some rather excellent examples of the P-3 type helmets used by the ex-Yugoslavian Air Force (courtesy of Serbian Miroslav Sekulic). These helmets consist of two main groups: 1) Actual US manufactured P-3 helmets that were imported by Yugoslavia in the 50s and used by their Air Forces with minor modifications (communications, etc.); 2) Yugoslavian license-made versions of the US P-3 helmet, manufactured in the early to mid-1980s, designated the Yugoslavian PK-07 Flight Helmet. While the earlier group were flown, but may be obtained today in very good condition (they were apparently either little used or well maintained), the later PK-07 examples that are also available were not ever flown and are consequently in excellent, unflown condition (although they do have some 'shelf wear' and bear other small blemishes and marks from storage). One of the side benefits of having access to these recidivist 'throwbacks' to the 50s, is a chance to compare them to surviving USAF flown specimens of the early 50s. Small details such as the riveted grab/lift flange on the (1980s manufactured) Yugoslav helmets stand out as original design details that as such are not found on most (updated) US versions that have survived today.
Hence, whether you limit your interest in helmets (as some American collectors do) to US made and used helmets only, there is still much to be learned about American helmets through such comparisons as these with foreign copies or foreign-made versions of certain models. I personally have gained a great deal of insight and enhanced understanding of the ever-confusing details of US P-series helmet history through my own examinations of some of Miroslav's excellent offerings.
The attached images show poor but viewable reproductions of two illustrations taken from the early USAF TO illustrating the above referenced "Early Visor, Type Original" and a close-up photographic shot of that system's "No J-arm" side-latch visor mechanism, as found on Rich May's "P-2" helmet specimen (pardon my rude enhancements drawn with blue pen to make details stand out and thanks to Rich for use of his image). It should be pointed out that Rich's helmet's visor also features an odd, presumably experimental grab/lift flange on it that was probably proposed and hand-fabricated, then added to Rich's helmet's conventional "Early Visor, Type Original" for purposes of testing & study.
So, what does all this tell us on this beautiful sunny day (at least it is here) about the endlessly interesting old USAF P-series helmets? Simply this: 1) Never, ever accept it as gospel that the final chapter on anything has been written when it comes to any aspect of life support and flight gear history! 2) Even the official USAF TOs can be dead wrong, at times. Happy collecting to all.
Cheers, (a long-winded but hopefully helpful) DocBoink