The History of and Guide To The US Hot Weather Uniform (RDF Transitional ERDL)

Transitional periods are often considered rocky, strange, somewhat chaotic, and usually to some level, disorganized. This is no exception when it comes to logistical transitional periods, and is especially the case when uniforms are involved. Though there have been a few notable examples of this, perhaps the most famous is that time span between the United States' tropical combat uniforms and their ERDL pattern, and the battle dress uniform and its woodland, as in between another period, something of a half measure, the hot weather uniform. More commonly known as the RDF cut or transitional ERDL uniform, these were something of a hybrid between the two becoming well known for their usage, but also because of their confusing variations and nature overall. Before getting into the swing of things, we first have to give a thanks to Venture Surplus for sponsoring this video. Focusing primarily on United States surplus and related gear, Venture has you covered for all sorts of modern, as well as older gear in a variety of patterns and pieces like UCP, MARPAT, and woodland. So, if you're in the market for US stuff, be sure to check them out, and while there, remember to use the coupon code HISTORY10 at checkout. Thanks again guys, now onto the video. To preface things, this one is going to be something of a mix between talking about the history but also a sort of guide to the uniform elements as far as common variants, some uncommon ones, experimental and adjacent pieces that are often lumped into the RDF uniform type, and then commercial pieces as well. That all being said, there are essentially two halves to this, the hot weather uniform, i.e. the uniform cut itself, and then the ERDL camouflage pattern, specifically the variant that's often referred to as transitional. Okay though, let's jump in by briefly covering the setup and the terminology often referred to with these uniforms. With the United States in the Vietnam War, the utility uniform, often called the OG-107s, quickly proved to be less than ideal for the climate, terrain, and a large portion of operations, and so in 1964, the tropical combat uniform began to make its way to troops in the region. With its own history and series of changes and adjustments such as features, elements, and fabric, over its lifespan quite a number of variants existed, but can be boiled down to Class I, which were made in the OG-107 color, and Class II, being the ERDL camouflage, which had a history of its own spanning all the way back to 1948. Anyway though, throughout the war and into the mid to late 1970s, numerous endeavors continued to not only equip forces there, but also update and modernize other uniform and gear components that would be seen beyond Southeast Asia after the war, with some examples being Linklo and Alice, PASGT with the Kevlar Helmets and Protective Vests, and for Our Story Master, or the Modern Army Selected Systems Test Evaluation and Review, which pretty much focused on camouflages and updating uniforms. Many of the just mentioned endeavors have already been covered in their own respective videos, so we won't get too much into the details there, but essentially a permanent and general purpose uniform and accompanying camouflage was still being developed as the threat of the Soviet Union and the Eastern Bloc in Europe were still very much a thing. All this would culminate with the development and standardization of the Battle Dress Uniform and US Woodland, but in between Vietnam and the early 1980s was the Transitional ERDL and this Hot Weather Uniform, which moved the general ensemble closer to the BDU, but kept elements of the TCU. Many have referred to them as the RDF, or Rapid Deployment Force Cut, as well as the Transitional ERDL Uniform, with both of these terms being unofficial ones and here's why. The initialism RDF is a short version of the RDJTF, or Rapid Deployment Joint Task Force, a multi-branch unit founded in 1980 but conceived in 1979 due to a series of destabilizing and power-shifting events throughout the decade in the Middle East, such as the United Kingdom's gradual withdrawal of its forces that were east of Suez, the Yom Kippur War in Israel, the 1973 oil crisis, the Soviets' increased interest and presence in the region such as its declaration of friendship with Iraq in 1972, an invasion of Afghanistan in 1979, and eventually the Iranian Revolution. The force itself was composed of specialty units from the Army, Marine Corps, Navy, and Air Force that could be sent quickly to regions of the world outside where the US had major presences, though it quickly shifted its main priority and focus to the Middle East. It would last until 1983 when it became CENTCOM, or the United States Central Command, which was assigned an area of responsibility that encompassed the Middle East and Central Asia. Being a new and significant unit, obviously they'd get newer and more advanced equipment, gear, and in this case uniforms, so naturally the hot weather uniform would eventually become associated with them. It's worth pointing out though that it's a generalized collector's term, as these began being created in the mid-1970s before the creation of the RDJTF and continue to be seen mixed in with BDUs through the mid-1980s after it became CENTCOM. Additionally, they weren't exclusively issued to RDF units, much like non-hot weather uniforms were reserved for everyone else. It really came down to the location, unit, tasks, and operation, but being as they were around during the same time period and the RDF operated mainly in hot environments, you'll often see them in photographs, which helped lead to the retronym years later. Before jumping into the actual uniforms though, the camouflage should be talked a little about, as these HWUs saw quite a few, but really only one in a way, ERDL. The pattern started off in 1948, but wasn't really used until the 1960s when it began being fielded in Vietnam, a la the slightly modified Green Dominant ERDL, however it was said to have been proven to be a bit bright, which led to the Brown Dominant ERDL, officially referred to as NLABS-1, which toned the shades down a bit giving it more of a, well, brownish color. Both of these were seen through the 1960s and into the 70s on many different items, but the primary one was the Tropical Combat Uniform, often just called Jungle Fatigues. However, the pattern continued to be refined and by the mid-1970s, NLABS-2, aka the Transitional ERDL, aka RDF ERDL, appeared, which improved the printing standards and process, essentially eliminating roller slippage, which had caused an effect referred to as ghosting, shadowing, or bleeding around many of the shape's edges, that had been seen on both Green and Brown Dominant versions, which resulted in them being more or less sharpened and perfected. Additionally, the color shades were once more darkened slightly, again moving them a bit closer to a temperate woodland scheme. All of this is brought up as they obviously are stages of the same pattern, which ultimately culminated in the creation of US Woodland, aka MNE-1, but also because all three of these patterns were seen on Hot Weather Uniforms through its short lifespan. It seems that these uniforms were something of a way to not only test out new concepts, but also as a means of using up existing stock of ERDL fabric, which saw quite a few interesting results, which we'll be seeing in just a bit. Okay, let's finally get into the uniform itself, but in order to do so, we first have to look at a Tropical Combat Uniform. As mentioned prior, these saw a few changes over the course of the Vietnam War, mostly with more hidden and minute differences. By the end though, the coat consisted of a simple five-button front closure, a two-button adjustable continuous cuff on each sleeve, a reinforced back yoke by the shoulders, two inwardly angled bellowed chest pockets that featured an inverted pleat at their center, were sewn down on their outer edges and roughly half the bottom, featured a single drain hole, had flaps that were tapered so that the outer portion was larger than the inner, and had curved lower corners. The one on the wearer's left also had a pass-through slot, as well as a small pocket inside for pens and pencils. Below those were two waist pockets, which featured all the same elements, minus the pen slot, but were sewn on straight rather than at an angle, and had two drain holes rather than one. When it came to the trousers, the final model had a zipper front fly, belt loops and waist tab adjusters, two inset waist pockets, two button-thigh cargo pockets that featured an overlapping box pleat, with angled flaps that tapered shorter from the wearer's front, which also had their front-facing edges partially sewn down. The pocket on the wearer's left also contained a smaller single-buttoned inner pocket that had originally been intended for survival or first aid kits, while also all but their rear edge sewn down too, two single-button inset rear pockets, and lower leg drawstrings akin to shoelaces. As mentioned earlier, these had been created in the early 1960s primarily for use among special forces, with references stating they took heavy influence from the M1942 paratrooper uniforms in many regards, yet as the war expanded, they were refined and updated while also becoming more of a standard uniform to many within the region coming in the OG-107 color, designated as class 1s, and both versions of ERDL, designated class 2s. After the war, the olive green TCUs would become more widespread among the US armed forces across the globe, while the ERDL ones, and really camouflage garments as a whole, became more reserved for special forces units. Now, these would get proper specification sheets in 1967, granted they would see a few revisions over the years, as well as federal stock numbers, not NATO ones as this was before the 1974 standardization. But anyway, let's look now at an actual hot weather uniform, which actually doesn't really have much different beyond the pockets. With the coat, they featured the same button-up front closure, same reinforced shoulder yoke, the same adjustable sleeve cuffs, and so on, but obviously now all four pockets were squared and angled at 90 degrees, rather than inwardly oriented. Looking closer though, they remained billowed, but now also featured hard straight corners and edges rather than the curved, featured the same inward pleat, had symmetrical rectangular flaps instead of tapered ones, and lastly, which is easily overlooked, all the stitching save the lower portion of the yoke started off in the same manner as the TCUs, where the seams were inside, however at some point they began to be double stitched on the outside, with many examples seeming to show this switch happening sometime in 1978, as both versions can be observed on the coats with contracts from that year. As for the trousers, they reverted back to a button-up front fly, which had been the standard with TCUs up through the 5th model, while the thigh cargo pockets changed in a similar manner to the ones on the coat, which again, was then becoming completely squared, changing to a single central inward pleat, the billowing was extended from the rear edge as it now included the whole lower portion, while also having a single drain hole. Finally on the back, the rear pocket flaps were also now perfectly square. So all in all, the changes really just came down to adjustments with the pockets, which can instantly be noticed as TCUs are angled with lower curved edges, while the HWUs are square with 90 degree ones. But what's the most interesting is that these two uniforms, according to stock numbers, are the exact same, even though the nomenclature on the tags say otherwise. Entering the stock system in 1967, the spec sheet for the TCUs underwent a few revisions with the change to square pockets likely being one of the later ones. But that now leads us to the question, why go back to square pockets when angled ones proved to be much more ergonomically and tactically efficient? Unfortunately the answer isn't explicitly stated anywhere, at least via a source that's readily available, but there has been quite a bit of speculation and conjecture which boils down to the angled chest pockets often being connected to more specialty units. First appearing in a big way during World War II with the paratrooper uniforms, a majority of the other uniforms created and fielded from the 1930's onwards continued to use squared pockets, granted often with assorted flap designs. Never really going away, the TCUs were more or less a reaction to the need special forces had for their duties in Vietnam, which eventually just expanded to many others as the conflict escalated and spread. Still endeavors to modernize and update uniforms progressed, with most of them continuing to feature squared and straight pockets. So naturally the general design of the TCU was just taken and the pockets swapped out while what eventually would become the BDU continued development. Additionally, the theory that the angled bellow pockets were far more complex, time consuming and costly to sew has been floated while the more folds and stitch work, as in the case of the trousers cargo pockets, could potentially wear and literally tear a bit easier over time so switching them to squared meant less surface area where stitches could be undone and so in general the design was sturdier and stronger. In the end though, they were sort of half right as certain elements of these were carried over to the BDU. The inward pleats of the pockets were removed entirely as they had a tendency to wear out or lose their shape over time, however the updated billowing and perimeter stitching methods remained, essentially cutting back a bit on expansion capabilities for the sake of overall durability. The overlapping box pleat design from the TCU thigh cargo pockets were brought back though, granted modified slightly. Alright, with all that out of the way, let's showcase a few of the more common examples of the hot weather uniform as thus far we've really only seen the transitional. If one were to rank the issued variations from most to least common, you'd have the transitional, then brown dominant, green dominant, and finally the solid olive green 107. But let's start off with brown dominant as these really lead right into transitional. Again, these continued to use Vietnam era fabric with all their print slippage and variance goodness. It's important to note that some versions may not have as much ghosting or fading and colors may be slightly different, and through uniform wear and fading it can sometimes get a little hard to identify these when stacked up against transitional. And speaking of transitional, that's next, which, as stated earlier, darken the colors slightly to a bit more of a woodland scheme while also addressing the print issues and thusly removing the roller slippage and ghosting. However, you can run into instances where this may not be 100% the case, like this one. With the top dated 1976 and the trousers 1978, the colors are something in between brown dominant and transitional ERDL as they're a bit more muted and dark overall but ghosting is present though not as rampant, yet the areas that are look much worse off appearing in some cases almost as if they were smeared or ran in blotches. The ghosting on the trousers seem to extend further than many examples on brown dominant ones, while on the coat it looks almost like the ink was running rather than slippage. Though it's possible this could just be a variant of brown dominant, it just shows that sometimes between brown dominant and transitional it can get a tad tricky to identify. Anyway, here's a quick comparison between brown dominant, that weird middle ground variant, and then the standard transitional ERDL. So in a way this middle point transitional ERDL could be interpreted as a transitional transitional ERDL, bridging the gap between brown dominant and transitional. Here's a fun game, count the amount of times I say transitional, dominant, and ERDL in this video. It's gonna be a lot. But now is green dominant, which is pretty straightforward and apart from the OG-107 is the easiest to identify due to its vibrant almost lime green colors where usually the tans would be. But that leaves us with the final version being the solid olive green. Unlike all the others, this variant seems to have only been made in size small regular coats and were worn among the OG-107 TCUs. The reasoning behind this isn't exactly known, but the going hypothesis is that TCU coats in that size more or less ran out during this time and instead of making more they just switched new ones over to the new cut. Interestingly, this garment is also the only one that retains the class designation, granted in the form of type 1 rather than class 1, identifying it as the solid OG color, however most of the ERDL ones don't have any mention of either. With these, quite a few people have said they were only seen worn by US Army Rangers, notably the 75th Regiment, as really only two photos have circulated of them in use. A photo of a Ranger during Operation Urgent Fury in Grenada in 1983, and a 1984 dated photo of 1st Platoon, B Company, 3rd Battalion. Well, that's not true, as there's actually images of them also being worn by other soldiers and even Marines, such as these. On the left is a 1983 dated photo of a Staff Sergeant in Honduras during Operation Ahuastara II, while the one on the right shows a Marine wearing one in 1982 during Operation Ocean Venture 82 held in Puerto Rico and other parts of the Caribbean. A going belief with these is that the early contracted sets were made in the green and brown dominant ERDL until the fabric was depleted and replaced with the transitional. This is even backed up by a 1982 dated Army Science Conference paper, Psychophysics of Modern Camouflage. However, it's not entirely that cut and dry, as there are examples of late contract ones like this green dominant from 1980 and early contract transitional from 1976, so it shows that these really were a mixed bag of sorts from start to finish, at least to some capacity. But being a mix and match, there were even instances where garments featured two or more variants of the pattern and even in some rare instances fabric types. Think ripstop for a majority of it, and then just 100% cotton sateen for just a small pocket section. Referred to as a clown variant or piece, these pattern mashups were often seen with smaller features such as the inside fabric around the waist being one color, while the rest is another, a single belt loop being different, and so on. However, there are examples like this one, where it's everywhere. Overall, this one is green dominant, but all of the pockets feature other colors, which look to be another example of the shadowed transitional. Some have even come across examples where close to half of the garment was one variant and the second another. And this likely came down to quality control and standards being relaxed or overlooked, and this even extends to normal sets too, as you can often run into some really salty pieces as some batches had a tendency to wear out and fade, resulting in some wonky colors, which continued to be a thing with many woodland BDUs after these were phased out. Additionally, you may run across some ones that seem like clown variants mixed with these faded types, like this coat in a brown dominant ERDL. That looks like it had an accident with some sort of bleach or discoloring agent on the sleeve. However, if it's flipped around, the back portion is perfectly fine. Even under the folds by the seams, the discoloring is seen, which makes one think this error with the fabric was there even before it was sewn together. Now beyond these versions and variants are some others which are firmly in the prototype, experimental, and very limited use sphere, and technically they aren't hot weather uniforms but do bear virtually the same cut. During the master tests, most of the experimental pieces were made into garments that had the same features of them. Additionally, during the development of the six-color desert pattern, many garments were made the same way. There's even the special forces airborne uniform used by, well, special forces airborne units but also Saudi Arabia. Granted, these had a few extra features too. Finally, one of the prototype BDUs which saw the ERDL pattern scaled up 60%, mirrored horizontally, and saw its colors adjusted some, also bear the same stock numbers as the hot weather uniforms which, as stated earlier, share them with the tropical combat uniforms. It pretty much is just one long series of deviations and changes. Okay, thus far we've talked about the patterns, colors, and the coats and trousers, but there were actually a few pieces of headwear too. Well beyond experimental and prototype ones, really only three, with the most common being the M1 helmet cover. Now these babies are wild in many ways, as no two are alike. Using the same specifications as introduced with the second pattern Mitchell covers, the only thing that makes them RDF or transitional is the ERDL pattern itself. But there's just so much variation in colors, which likely boiled down to the different fabric types and numerous contractors that produced them. Seeing as they wore out much quicker than most other pieces, many more had to be made, leading to way more fabric and printing batches. Next up is the 8-point utility cap. These were actually the first ones made in an ERDL pattern on a massive and official scale, as well as ones in ripstop, as prior ones were mainly cotton sateen OG-107s, with any other ripstop and or ERDL ones being custom or commercially made. The one seen here is a Type 1, meaning it's the one with the Marine Corps EGA. Type 2s, or ones that are blank, are seen in period photos, however don't seem to really appear a lot, meaning they were likely produced in far fewer quantities. Finally are two somewhat strange ones, as they sort of land somewhere between official and unofficially official. First up is essentially an OG-107 patrol cap made from polyester and cotton. These were the ones that fall in between the M1951 version of the cap and the BDU ones, as the utility baseball style caps were the standard during that period. Inside they bear tags with all the proper terminology and numbers, but specifics like NSNs, however, when searched, have no info for them available beyond a cancellation date of 1984. So it's a toss up if they were official, or some sort of limited produced commercial item, or modified thing, or whatever. In something of a similar vein are sunheads, more commonly known as boonies. Supposedly, like the uniform itself, these share the same spec sheets and stock numbers as the green and brown dominant ones, which were first introduced around 1967. The problem with these is there's plenty of pictures of them online, however they're all newly produced ones by R&B Inc., a contractor that made original ERDL ones way back then. Many sellers have stated that R&B has made it clear these are newer ones produced to the same specifications and with original leftover fabric, and to make things a bit more muddled, they've been manufactured with two different tags inside, one that uses made up contract and stock numbers, and another that doesn't, as the more legitimate looking one features a 1971 contract date. But on that note, we've got one final element to cover, commercial pieces. Starting simply with the pattern, there's actually not a whole lot out there beyond the aforementioned boonie hat, with the only other thing of note being M1965 field jackets. Still being made in OG-107 during the era of the hot weather uniforms, these were no doubt sold as an item that could be privately purchased as they were made to military specifications and obviously match the camouflage WUs. As far as the hot weather uniform cut, the design was, like many other uniforms that preceded and superseded it, spun off into uniforms anyone could buy extending past the introduction of Woodland and the BDU. One well-known brand that made these was Gung Ho, which produced a number of versions such as Khaki, an iteration of Tiger Stripe, Six Color Desert, and Woodland, which in the ensuing years has occasionally led to some confusion and getting collectors' hopes up about finding a prototype or experimental piece, only to realize it's a Gung Ho one with its tags worn out or removed. But this feels like a good point to start to wrap things up. Now obviously a lot was covered, but it's entirely possible some more obscure elements or even pieces were missed. It's within the realm of possibility there's a pair of trousers or a size medium long coat in the OG-107 color, but they've yet to be photographed or shared in any major way. There could also be other commercial pieces, whether they're new or old, or even a proper specification sheet for the hot weather uniform altogether floating around somewhere. But trying to track down every possible variance with these uniforms could drive someone insane, and honestly that's kind of half the fun, especially with weird transitional type uniforms like these which pretty much mixed throw whatever's left at it to use it up and let's test out some new things while keeping a bunch of older things to it. All that though makes the Hot Weather Uniform, aka the RDF Cut, aka the Transitional ERDL Uniform, and so on, such a unique and interesting uniform through and through. Thanks again to Venture Surplus, and hopefully this video was informative and helpful to those curious about or trying to collect its pieces. If so, perhaps leave a like and subscribe if you haven't yet done so. If not, you need not worry, just be sure to check back soon for more of the history of, and well, guide videos, right here on Uniform History.