In addition, Vought improved the area ruling of the airplane. There had been considerable concern before the first flight of the prototype F8U fighter when wind tunnel testing showed transonic drag to be higher than had been predicted. Vought hadn't paid much attention to the newly discovered area-rule concept up until then and hastily developed a set of modifications to refine the fuselage shape in accordance with it. One or two were actually incorporated prior to first flight, as a result of which it was discovered that the wind tunnel data was not correct and the F8U's long, slim fuselage was close enough to an ideal overall cross-section increase and decrease.
However, with area ruling in mind, Vought tweaked the F8U-1P fuselage cross section, bulging it both upward and outward between the cockpit and the wing, in part to provide a flat bottom to the fuselage (also see the profiles in the picture at the beginning of the post).
A Tom Weinel created comparison:
The upper forward fuselage faired into a larger overwing fairing. (Also see the top picture.)
The inflight refueling probe, which had been added to the fighter in a large blister aft of the cockpit as an afterthought, was now fully enclosed within the fuselage. A window was added to the underside of the nose cone for a viewfinder so the pilot could accurately position the airplane for photography. The pilot could switch between two lenses, one with a narrow angle for use with the forward-facing camera (station 1) and the other, a wide angle for use with the cameras at stations 2, 3, and 4 which took pictures downward and side ward.
The instrument panel was dominated by the viewfinder.
Like the F8U fighter originally, the first F8U-1Ps had Vought-furnished ejection seats. These were replaced by the Martin-Baker seat, probably during the very late 1950s or very early 1960s. See http://thanlont.blogspot.com/2011/02/transition-to-martin-baker-ejection.html
The F8U-1P's fuel capacity was increased by 224 gallons over that of the F8U-1 fighter by extending the main fuel cell downward into the volume provided by the elimination of the rocket pack and adding a small fuel cell forward of the main fuel cell. This provided a significant improvement in mission radius and endurance.
The F8U-1Ps were redesignated as RF-8As in September 1962. Seventy-three of the original 144 were rebuilt between 1965 and 1970 to add an uprated J57 and ventral fins; these were designated RF-8G and retained their original BuNos. (Five Marine Corps RF-8As reportedly got ventral fins early; high-speed directional stability was marginal without them.) At least some got the later wing with hardpoints for external stores and wiring changes for an ECM pod.
A subsequent upgrade in 1977 resulted in a change to the more powerful J57-P-420, which required the addition of the external cooling intakes on the upper aft fuselage; there was, however, no change in the designation.
Various ECM antennas were added to the vertical fin over time, including a large forward-facing one.
The bleed air exhaust on the right side of the fuselage just ahead of and below the wing leading edge had a less prominent fairing than the fighter's.
The last iteration of the RF-8G also was converted to later single-duct configuration as depicted in this Tom Weinel illustration:
For a walk-around photos by Chris Ishmael of an RF-8G with the external AB-cooling intakes in a museum, see http://www.cybermodeler.com/aircraft/f-8/rf-8g_walk.shtml
For some illustrations from the flight manual, courtesy of the Marine Corps Aviation Reconnaissance Association, see http://www.mcara.us/F8U-1P_RF-8A_design.php
There are were no complete kits of the F8U-1P/RF-8 until late 2023, when Sword released an excellent 1/72 one. See http://tailspintopics.blogspot.com/2023/12/sword-172-f8u-1prf-8-photo-crusader.html.
Also in 1/72 scale, there are vacuform conversions from Falcon and Airmodel and resin conversions from Ventura (see https://hangar47.com/rf-8a-crusader/) and RVHP; only the RVHP kit includes decals and its accuracy is questionable. There is a review of the 1/72 Final Touch conversion parts and Tasman decals here: http://modelingmadness.com/review/viet/mansrf8.htm. As far as I know, only the Falcon version is readily available. See http://www.falconmodels.co.nz/kits.html
In 1/48, see Tom Weinel's post in Hyperscale HERE.
Last, but definitely not least, Fisher has released an excellent RF-8G conversion for the Trumpeter 1/32 kit. See http://fishermodels.indiemade.com/product/rf-8g-photo-crusader-conversion-132
Hi Tommy
ReplyDeleteAnother great post. Tom Weindel's post can now be found here; https://www.tapatalk.com/groups/hyperscale/have-any-of-you-read-blue-moon-over-cuba-thanks-ge-t485033-s10.html
From 1975-1977, I was one of the tiny group of engineers responsible for the last 30 or so RF-8Gs at the Naval Air Rework Facility in Norfolk. A lot of things stick in my mind, probably of no interest to anyone these days. You mention the ECM antennas, from memory the last ones I personally saw were Airframe Changes 598 and 599. I don't think any two of the aircraft that came into our shop ever had identical antenna configurations, and we'd incorporate everything they had missed along with the latest stuff, so theoretically they'd leave our line all with the same equipment. That didn't apply to the cameras though. There were different numbers and locations of windows on the various airplanes, and we couldn't do much about that. One odd thing about the F-8 series' wings was that occasionally we needed to remove the upper skins to check for corrosion on the spars and ribs inside, which involved drilling out the fasteners and stacking the upper skins off to one side. When it came time to put the skins back on, it could be challenging to get the holes lined up again, and there was a lot of line-reaming that had to be done. This, and the original drilling-out process, left metal shavings inside the wing fuel tanks that would clog up the fuel filters if left alone, so it was standard practice to pour a thin layer of sealant into the floor of the tanks to glue them down. But the airplanes had been in service for decades and so this process had been done multiple times, so there was eventually a loss of fuel volume as a result. Nothing could be done about it though. We did change entire wings in some cases with ones from "boneyard" F-8s, F-8Ls (I think - it's been a long long time since then) and got increased service life as a result since those fighters had been retired much earlier in their service life than the photo-recce Crusaders, so they had less fatigue life on them. They also had titanium spars, which was a bonus in our minds. You mention a rumor that the RF-series had smaller stabilators than the fighters, but as far as I know that's not the case. I certainly never heard it at the time. One VERY cool thing the F-8 had was something that helped pilots eject with that awful Martin-Baker seat. The pilot could push a button that would activate a pneumatic piston, driving a horn-shaped piece down over a matching piece on the stabilator pivots that would lock the stabilators firmly in place, at a position that gave the F-8 a slight nose-up pitch attitude. No worries then about the aircraft taking a sudden dive when reaching for the ejection handles. One of the most famous F-8 ejection photos shows the locked position: https://theaviationgeekclub.com/wp-content/uploads/2019/04/VF-154-F-8-Ejection.jpg
ReplyDeleteSword just came to the rescue with two seperate boxings for both the RF-8A and RF-8G. Only differences are the instruction sheets and decals.
ReplyDelete