F-111 Inlets
by Jim Rotramel
A
pair of Combat Lancer F-111As are shown with a pair of under-fuselage AN/ALQ-87 ECM pods
and weapon bay M61 gun installation. What can’t be seen is that when these
aircraft flew combat missions, an AIM-9B was tucked in the left side of the weapon bay on
a trapeze! The red, white, and blue pinstripes angling down from the cockpit of the lead
aircraft identify it as Lt. Col. Ike Dethman’s aircraft, 66-018. |
A pair of Combat Lancer F-111As are
shown with a pair of under-fuselage AN/ALQ-87 ECM pods and weapon bay M61 gun
installation. Note that there was only a UHF antenna under the nose and the unusual shape
of the outboard weapon pylon. Other modelers
have often expressed amazement that while I have over 1,000 hours flying F-111s, I
don’t have a model of one (other than company models). I probably should have built
the Hasagawa 1/72nd kits, which are pretty good (except for the Pave Tack pod). But, the
focus of this series of articles is the 1/48th Minicraft kit. While it captured the
external shape of the aircraft, it has many faults. I’m going to show the real jet
through a modeler’s eyes. I’ll address the existing aftermarket kits that
I’ve seen and give you an honest appraisal of what I think about them. Unfortunately,
to do a really accurate kit is going to cost you about four to five times the cost of the
kit in resin. One can only hope that maybe Trumpeter will attack this subject at some
point.
IMPORTANT!!
If you’re like me, you like to look at the
photos and skip the text. There are a lot of important tidbits in the text of these
articles.
Inlets
By far, the worst error in the Minicraft kit was the engine inlets. Neither
inlet style depicted by the kit even remotely captured the feel of the actual articles.
Operational F/EF-111As, F/RF-111Cs, the first FB-111A
(67-0159), and the canceled F-111Ks were fitted with Triple Plow I inlets, which featured
hydraulically translated cowls.
The remaining FB-111A/F-111Gs, as well as all F-111D/E/Fs
were fitted with Triple Plow II inlets, which featured three ‘blow-in’ doors.
This redesign increased the separation between the inlets and fuselage, removed the
external splitter panel, and featured inlet spikes 18-inches longer than the Triple Plow
I’s. The fuselage of Triple Plow II aircraft angled back ever so slightly at the
inlets to create more room between the two structures. These aircraft also featured a
small, round inlet between the engine inlet and the fuselage. Finally, the F-111D/E/F and
FB-111A all had a pattern of gray, and/or fiberglass-brown panels of radar adsorbing
material (RAM) on the interior of their inlets.
A couple of “special cases”: The second FB-111A
(67-0160) was fitted with Super Plow inlets, which were similar to the Triple Plow II
except that the translating cowls were replaced with two ‘blow-in’ doors instead
of three. The first five F-111Bs (151xxx) were fitted with essentially Triple Plow I
inlets, while the last two (152xxx) had essentially Super Plows. Refer to the Ginter Book
on this subject for details.
While the Triple Plow II inlet reportedly increased
inlet area by ten percent, it’s unclear if that was precisely true. Measurements of
the inlets suggest the TP II may be marginally larger than the TP I, but nothing like ten
percent. However, the frontal area of the inlets may have increased by that much because
of the shifting of the inlet farther out from the fuselage.
Prior to engine start, the TP II blow-in doors (or TP I
movable cowl) were closed, opening as the engines powered up and sucked open the blow-in
doors (or the cowls opened). They remained open until after takeoff, when sufficient air
could be provided by the intakes alone. After landing they again opened to increase the
air available to the engines during ground operations.
Triple
Plow I inlets (left) were most easily distinguished by the large splitter panel. Note how
the inlet spike barely reached the local Mach probe. Triple Plow II inlets (right)
eliminated the splitter panel and the inlet spike was 18 inches longer than on the earlier
inlet, extending well past the local Mach probe.
This view of the TP I
inlet on the left clearly shows the warped shape of the splitter panel and the lack of
inlet RAM. Note how far inboard of the local Mach probe the spike is. The TP II inlet on
the right shows how far outboard the inlet was shifted (note how close the it is to the
local Mach probe), the length of the inlet spike, and the inlet RAM.
The
TP I translating cowl (left) and the triple blow in doors of the TP II inlet (right).
No aftermarket correction sets have been
produced to correct this serious error, although Scaledown has it on their list of things
to do. In addition, they’ve promised seamless intakes at some point as well.
Edited by Assistant
Webmaster
David de Botton - Flash@F-111.net
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