Boeing's Chase and Photo Airplanes
Friday, December 4, 2020, Boeing retired two of its long serving chase
airplanes - Lockheed T-33s. I went to Boeing Field to watch their last
flights (for Boeing Flight Test) and wrote an email covering the occasion to some of
my pals. Some responded with even more info and pix, so I decided to
morph the email into a webpage.
Airplane manufacturers have long used chase planes to monitor test
progress of experimental airplanes, take photographs and also conduct
public relations and advertising photo flights. I've been around
the periphery of some of those airplanes used by Boeing in
Seattle. Doubtless, others were used - for sure in Wichita - and
also by Boeing ancestor companies, so this is more like a ramble and
not an in depth treatise. When you get old, you ramble a lot. If I get any more info of interest, I'll add
it to the page.
My first data on Boeing chase planes comes from investigation work
did on the crash of the Boeing 307 Stratoliner Prototype near Alder,
on 18 May 1939. The flight was a half-demo/half test for TWA and
customer KLM. The airplane went out of control and entered a flat
spin while performing a stall with both engines out
on one side. During the spin/dive recovery, the airplane broke up
in flight. All 10 aboard were killed. With no Voice or
Flight Data Recorders, the pictures
taken by the chase aircraft were important elements in the crash
This photo was taken with engines 3 and 4 shutdown just before the stall was attempted. Note the rudder position.
Later on, in the early to mid-1950s, Boeing chartered Pan Am
Stratocruisers, for P.R. photo flights. I got these photos from
Scott Carson, riding along as a kid with his dad, test pilot Kit
Carson, and shows the PAA Strat with windows and hatches removed
to allow clear shots by the Boeing photogs.
By 1963, when the 727 came along, Boeing was doing a similar charter
operation, but with PNA (Pacific Northern Airlines) who used Lockheed
Constellations. These airplanes were used for the first flights
of both the 727 (1963) and 737 (1967). In these photos, from James Raisbeck, you can see the
Connie parked at Renton airport as the first 727 taxies out onto the
runway for its first takeoff (Feb 1963.)
and - first flight photos from the PNA Connie!
The Connie was also used for the First Flight of the 737 below (April 1967)
Later on, Boeing switched to using its own airplane, E2 - the
second 727, - which was then used for photo work.
E2 - N72700
Here's a photo taken in
March 1969 from E2 of a Nordair 737 during a test flight over the
Olympic Peninsula - I was aboard the 737 and could have taken some
dandy pix of it (E2) - if only I had had my camera along.
When E2 was retired from flying, Boeing used E209, a 727-100 they
bought second hand off Lufthansa; and also E5001, a 727-100C Universal
airplane that had been used for flight testing and demo work.
At some point around 1974, Boeing acquired a North American F-86 (actually a
license built Canadair version CL-13B Sabre Mk. 6 - one of 1815 Canadair-built) for chase and photo duties. It
was often flown by Paul Bennett ("Pablo") who had a great time in that
airplane, much to the jealousy of other Boeing test pilots. In 1991, after
wing structural problems were found on inspection and deemed
unrepairable, the F-86 was donated to the Museum of Flight - where it
can be seen today, painted in original RCAF markings.
You can see the Saberjet here flying alongside
the 747 Prototype.
During this time period, Boeing acquired no fewer than 4 Lockheed T-33s
(T-Birds), again actually license built Canadair airplanes (they built 656.) See story below. The
interest in the Canadair airplanes likely sprung from their having
alternate engines, that were more powerful and also more reliable (see Notes at
the bottom.) The T-33s were acquired over a period of time, and
were used in assorted testing associated largely with the ALCM (Air
Launched Cruise Missile) program, but later shuffled into the Boeing
Commercial chase spot.
These were known - appropriately as Red Bird and Blue Bird
In 2006, Boeing stored one of their airplanes - Blue Bird - in one of the Museum's
Everett hangars and I used the opportunity to grab a few close-up
The T-Birds offered many desirable features - they were rugged,
reliable, simple and economical to operate; offered two seats (vs the
single seat F-86), and had a large canopy with great visibility for
both chase and photo work. They also had a large nose compartment
which made them able to carry lots of ancillary test equipment.
Somewhere along this journey, the T-33s became somewhat limiting due to
speed; they are not very fast airplanes. The 747 was faster and
could hit nearly M 1.0 during dive testing. So a Northrop T-38
Talon (N38FT) was added to the chase fleet.
I took these photos in 2002 at an Air Show in Moses Lake. You can see my 737 Prototype (NASA 515) in the background.
They asked if I could bring my airplane over for the Air Show. I said: "SURE!"
Good thing NASA/Boeing/Museum/FAA didn't know......
Everyone knows I was always scrounging for helpers.
This was my Co-pilot - did a damn fine job! Probably a Capt. over at Southwest or United now.....
Finally, in December 2020, after more than 40 years in faithful Boeing
service, the 66 year old historic Lockheed fighter/trainers - were
retired. Originating as the XP-80, designed by famed Lockheed
designer Kelly Johnson, the airplane type first flew in January 1944,
after being designed, built, and flown in an astonishing 143 days -
USAAF had demanded 180 days - in what became Kelly's famous Skunk
Works. (It could have flown in about a week's less time, except
the first engine blew up during a ground test right before the first
flight and a new engine had to be flown over from the UK.) It
became America's first operational jet fighter, serving in Europe
before the end of the War (although not in air-to-air combat), and
later in Korea (where 277 were lost in combat.) P-80s were the
first jet aircraft involved in dogfights kills between jet fighter
aircraft - as both victor and victim of the MIG-15.
It went on to
serve under numerous designations, by multiple Air Forces and also
Naval services on board carriers, became a 2-seat trainer (T-33 - 6557
built - flown by more than 20 different Air Forces, and for
decades was the Western World's primary military jet
training airplane.) The airplane was also built under license in
Canada and Japan. A total of 8272 airplanes are believed to have
The P-80 was also the basis for the more advanced F-94, of which about 854 were built.
Kelly had been proposing a jet fighter to USAAF for years, having
learned about compressibility problems when the P-38 started coming
apart in dives. He knew then that that was the end for propeller
airplanes; but USAAF wasn't interested. Then a funny thing
happened -- Me-262s started showing up in the skies over Europe,
initially during test flights (the 262 first flew in April 1941, and
entered combat ops in July 1944, and by War's end was claimed to have
shot down 542 Allied aircraft.) "Hey, those guys can't do that,
can they?" Kelly got a call to come to Dayton ASAP. He
arrived back in Burbank with a contract to build a jet fighter, and to
be quick about it. At least that was his story - to his bosses,
whom he had forgotten to tell (he played that game often.) They
had a fit, telling him (truthfully) that there were no people and no
space for any more airplanes (Lockheed had swollen from 33 employees to
94,000, and were building P-38s (over 10,000), B-17s, Ventura's and
Hudson's, and Connies. They told him since he got himself in the
pickle, he'd have to get out of it - by himself. With a long
face, he muttered "OK", and left with the biggest smile anyone had ever
seen. He'd been bugging his bosses for years to allow him to
create a Boutique shop within the company to fast build cutting edge
designs. Now they had given him the License.
Having spent a lot of time building the Electra, P-38, Constellation,
he had a pretty good idea where to find the good folks at the plant,
and proceeded to steal them (his words) to man his new shop. They
took all the plywood panels from engine shipping crates and built a
high wall enclosing an area in a corner of Burbank; it had no roof and
eventually wound up with a circus tent type cover. It became
known as the Skonk Works (not Skunk) named after an Al Capp comic
strip, because nobody knew what was going on inside. And Kelly
wasn't about to tell them!!! (Allegedly, "the project was so
secret that only five of the more than 130 people working on it knew
that they were developing a jet aircraft.")
After the War, Kelly filed a Patent for the airplane
They trucked the Prototype (Lulu Belle - another Al Capp comic strip
character - and still extant - now in the Smithsonian) covered by tarps
and with a phony wood propeller, out to Muroc Dry Lake (now Edwards
AFB.) Milo Burcham was the pilot; everybody from the Skunk Works
was there from the janitor on up (as always, with a Kelly first
flight.) The flight lasted 6 minutes since Milo couldn't get the
gear up. They adjusted a gear squat switch and he took off again
for Nbr. 2. The second flight lasted 20 minutes during which time
he "climbed, stalled, rolled, zoomed, and buzzed the field." In
Milo's report, he stated "During the descent, I worked the speeds
up slowly. I reached a maximum of 490 indicated airspeed and
everything felt good. Cockpit was quiet. Visibility is
good.... I made a low pass across the field with full power, 9500 rpm,
and reached 475 indicated airspeed. After pulling up, I made a
series of rolls, in both directions. The airplane rolls extremely
well and has a very fast rate of roll."
So, here's America's most advanced, secret airplane, and with about 15
minutes total air time, the pilot tears up the field at max power and
airspeed, then does a vertical climb doing max rate rolls in both
directions. 'Jes like today, eh??? Well, it's 76 years
later and some of these airplanes are still working for their pay, so
they must have done something right....
Shaking hands with Lockheed Test Pilot Tony LeVier before the first flight of the XP-80A - the second airplane built.
It was built in 138 days and the flight took place on June 10, 1944. It was named the Gray Ghost.
On March 20, 1945, it's engine turbine wheel failed, cutting off the tail section; the pitchover then failed the wings.
Tony bailed out with great difficulty, almost killed, he broke his back, and wound up in hospital for about 8 months.
There were no ejection seats in those days.
Gray Ghost returns to Burbank
Earlier, on 20 Oct 1944, Milo Burcham, pilot of the first flight, was killed when the engine flamed out on takeoff from Burbank.
Test Pilots - especially in earlier days - had a very dangerous occupation....
On Friday, December 4, 2020, both Boeing aircraft, registrations N109X
and N416X, took off from their home base at Boeing Field for a
formation farewell flight. The chaseplanes then flew to Paine Field for
a salute to the local Boeing workers (flying right past my home in
Hansville in the process!) Thanks to a heads-up from Boeing
Historian Mike Lombardi, me and the Missus flew down to BFI this
morning in our RV-12, and were in position to record the event.
Although both aircraft are usually referred to as T-33s, (actually T-Birds
is what most call them), they are actually Canadian license built
Canadair CL-30s (CT-133)(RCAF designation T-33AN Silverstar 3).
In an interesting quirk, Boeing's F-86 was also a license built
N109X (construction number T33-298) was delivered to the RCAF as
21298 in 1954. It was retired in 1965 and became CF-SJZ. One year later
the trainer became N109X registered to Aeronautical Specialties Inc,
Long Beach (CA). N109X was acquired by the Boeing Equipment Holding Co,
Seattle (WA) in 1976.
N416X (c/n T33-369) started its career in the RCAF too. Delivered
in 1954 as 21369 it remained in service until November 1970. The
aircraft was then sold on the civilian market and became N12416 in
1973. It had several owners before being acquired by the Boeing
Equipment Holding Co, Seattle (WA) in 1980.
On 16 November 2000 the ownership of both aircraft was passed on to the
Boeing Logistics Spares Inc, Seattle (WA). The T-33s have served as
observation/camera platforms during a number of historic maiden flights.
In 2010, one of the aircraft followed the Boeing 787 prototype during
its maiden flight. On 16 March 2018 the prototype Boeing 737 MAX-7 was
escorted while the prototype of the Boeing 777-9 was followed during
its maiden flight on 25 January 2020.
The T-33s are said to be replaced by TA-4 Skyhawks - an example shown here in a photo I took at Boeing Field in 2016.
The two T-Birds will be donated to two unidentified museums.
Man, I have a big trapline!
After sending out my emails, I got comments and more photos from some
of my pals. Here are a few nice pix from Tom Imrich, retired
Boeing test pilot, showing the T-33s and T-38, chasing the 747-8 and
In formation for take-off - First Flight 747-8
........and for landing
Following 3 pix from Tom Imrich - Co-pilot on FF
From the cockpit of the test airplane
T-38 in foreground and T-33 on the outside
Tom dug out some
memorabilia from his logs and records - recounting his first T-Bird
flight - way back in 1966, also his first jet flight:
Here's another one of my very memorable T-Bird flights... It was my first
nickel ride in a T33. With AF Capt. Jim Pettigrew. checking my logbook... that Lockheed T-33A flight was actually on
5-27-1966 in AF35605,... with a J33 (4600# thrust).
I got 7 T&Ls, flying both at Hanscom (1) and Pease AFB (6), including a GCA,
and acro... with a cloverleaf, barrel roll, a stall, an Immelmann,... and
even an SFO.
We ran the bird out of fuel twice that day, once to Pease, then again after
refueling at Pease, on the way back home, before landing.
And... I was still only age 19 ...not 21!!!
What a day that was!
Geez, how do you get that kind of Luck???? Well, I did get to fly a P-40 - click here. Take that, Tom!
Leon Robert is another pal - retired Boeing test pilot - and also a neighbor. He wrote me the following:
N109X was purchased by the Boeing company in the 1970’s to support the
development of the ALCM cruise missile guidance system. The large nose
compartment was key to that capability. The airplane was used to fly
low level test flights simulating missile profiles of less than 500
feet agl. The FAA waiver in those days was very simple. It read some
thing like “approved for flight at speeds greater than 250 kias at
altitudes below 10,000 feet msl, and for flight at altitudes less than
1000 ft agl in the NW region for the purpose of flight testing.” After
the missile was itself in flight test, the airplane was used to fly the
planned missile profile to ensure it was a safe profile. Since the
terrain data was recorded during the airplane test, it also gave data
to compare with the actual missile flight. Two anecdotes: 09
X-Ray was in Nashville flying tests over different terrain and
vegetation when Mt St Helen’s blew its top. A week later, when I tried
to come home, it had to short-stop in Billings due to a failed fuel
boost pump. Even there, the ash was a problem. One of the strangest
tests I ever flew on the Red-bird was for a INS issue. The engineers
wanted a short flight with maximum excitation in two out of three axes.
Their plan was to takeoff and fly true East. Then when clear of Seattle
area traffic, they wanted a series of 4 G loops on that due East
heading. Then on the last one, they wanted a 1/2 Cuban 8 that finished
on a true West heading for the return.
N12416 (later N416X) was initially leased, then purchased a few years
later. It was acquired in order to test the designator and seeker
system for an anti-tank missile. This was a Boeing developed system
that was able to self designate multiple tanks. The system was named
MCGD, and consequently this T-33 was called Maggie. Although both
airplanes were often called “red-bird” and “blue-bird” because of their
primary color. The flight testing for Maggie usually consisted of low
altitude “pop-up” bombing runs on tank-like objects. These might be
leased garbage trucks at Ft Lewis, or actual National Guard tanks south
of Boise. The fly-off with the competition occurred over a period of
several months using the Eglin AFB ranges and targets. Boeing lost that
competition, although the system worked well. While in Eglin, Boeing
program officials briefed Jimmy Doolittle on this system. I was
fortunate enough to meet him then.
After both programs ceased, the airplanes were almost sold, but then
they became the slow flight chase birds when Boeing began using T-38’s
for the medium and high speed photo chase.
Before the T-38, the F-86 was fully capable of flying both slow and
fast chase points. The F-86 was aerodynamically capable of flying very
high speed, but it was underpowered, so could not maintain those
highest flutter end-point speeds except in a dive. It was retired due
to a crack in the wing structure.
Bob - I don’t know if you want to use the info above. Feel free to use
some or all or none, as you see fit. I wish I had known today was their
last day. I was hired by Boeing in 1980 (from Flight Test Engineering)
for the purpose of flying N109X ALCM test flights. My USN A-6
experience qualified me for the low altitude work that was required.
They gave me a desk in the the production office, and then later let me
fly as co-pilot on Production flights. 109X is how I became a Boeing
from Jim Musgrove - the story about the "other" two T-Birds!
Well I have wondered whether they would pull the plug this December on
the Boeings “T-33” aircraft. It was planned two years ago. Or come up
with a workaround to keep them flying. Boeing operated these aircraft
longer than the USAF had them in the operational inventory. It was the
Cost of Ejection Seat Rocket motors that foretold their retirement.
Actually CT-133's built by Canadair. Boeing at one time had 3
operational CT-133's N109X, N416X, N490X. While N109X, N416X were
utilized in multiple programs in radar development as both emitter and
targets, certification chase in both research and product development
of Boeing products, N490X was purchased directly from the
Canadian Air Ministry to support the X-45 program and after completion
of the program fell into disuse and finding no subsequent program that
was willing to pay the utilization costs, eventually fell victim to
expired ejection seat ordnance. Which was by both time and cost to
acquire what drove a nail into its further flight. N490X was eventually
removed from the federal register in order that it no longer show as an
aircraft on the Boeing inventory and thus did not have to have its
utilization tracked in daily reports. Besides N490X it is a little
known fact that Boeing had an additional CT-133 making four aircraft in
total; The last of which Boeing acquired through the purchase from the
Canadian Armed Forces as a spare engine which Canadian pilots delivered
via flying it to Boeing Field. At the delivery, the CT-133 which has
never been a US registered aircraft or flown by Boeing was utilized by
the Boeing maintenance team as an engine test bed. That aircraft was
eventually ordered into storage to make more room in the WWII wooden
hangar “Hangar One” at north Boeing Field Seattle where the aircraft
were housed and maintained. The aircraft was disassembled, crated, and
sent to Glasgow Montana for storage in the Boeing facility there with
no engine installed. N490Xs disposition as of this time is unknown to
me. As an unflyable aircraft it will have to be either disassembled
stored or scrapped or possibly be donated to a museum.
from friend and Museum Docent Randy Getz - retired USAF and NWA
I’ve got about 300 hours in the old Lockheed racer. I think we have the
last one built for the Air Force (1959) on display down at McChord
from friend Ken Mist in Toronto:
Hello Bob. Thanks for sharing this. I will always have a soft
space for the T-33 (especially the Canadair CT-133). I'm a life
member of the Jet Aircraft Museum in nearby London who fly a CT-133 in
the paint scheme of the famous Red Knight and as well have spent time
as a safety briefer with Waterloo Warbirds for their "Mako Shark"
My most memorable time with the T-Bird is as a backseater when we
landed short at the Hamilton Air Show in 2012. I can personally
attest to how strong these old trainers are.
Will you be creating a web page to celebrate the retirement? I'd love to share the story and your photos.
From friend Gerry White in New Mexico - retired USAF and NWA pilot:
Thanks for that Bob.. When I entered the AF flight training the T-33
was being phased out in favor of the T-38 but Craig AFB, where I was
attending still had the T-33 as the primary training airplane. It was a
somewhat difficult airplane to fly as the attitude indicator would
precess and tumble when you pulled a few G’s and the radial flow engine
had a fuel control unit that would overheat the engine. When you had to
add power you had to concentrate on the EGT gauge while moving the
throttle to try to keep it below 800 degrees. It was somewhat unstable
also and you weren’t allowed to spin it as it had a tendency to tumble
and that was unrecoverable.
I found out why the physical for entering pilot training had a
restriction of sitting height of 36”. The first time I took the
physical the attendant told me my sitting height was 36 1/2” and that
would disqualify me so I managed to hunker down and got my sitting
height to 36”. I found out why it had that restriction the first time I
lowered the canopy and it hit my helmet. If I had to eject my helmet
would be the first to hit the canopy and that would have been a bad
I liked flying the T-33 as it had incredible visibility and it felt
like it was a real fighter. Managed to get a little over 200 hours in
From Harry Sievers - noted aviation historian and photographer:
MANY THANKS for this msg. remember the T-Bird very
well. in USAF 1952-1956 and spent 2 years at Itazuke AFB,
Fukuoka including last 8 months of Korean War. was in
Air Traffic Control and watched many T-Birds, including
the RT-33 from my job in control tower. they would "lead"
a combat mission taking off for the first 90 miles across
the water until they hit Korea, then return. had a chance
to ride on a local T-33 flight but it canceled at last minute.
did get several rides in USN JD-1;s, (B-26) in cockpit, so
did ride in combat aircraft. also at JITA was unit of F-94
from same family of F-80 aircraft. they flew every day on
intercept missions during war for unknown targets heading
to Japan across China Sea.
Keep up your GREAT reports, really enjoy them.
From my Bro, Tony T.
A beautiful airplane. Like Kelley said, if it looks right it will fly right.
...from one who wanted to remain Anonymous:
More trivia (but I'm not going to put it in a public forum).
During 747-400F flutter testing when we did the high speed dive points,
the T-38 piped in with something to the effect of "I think we're
supersonic". Turns out the flight test pitot probe heat was
miswired and there was no heat in flight. the probe iced up and
since we were flying to the cone airspeed..... Yes, the -400F
went (just) supersonic over eastern Montana. Not one of FT
Instrumentation's most glorious moments.
from Bernie Turner, Boeing engineer, regarding the F-86:
I was invited to go along as an observer on a 737 test flight to see
how the gravel deflector ski worked on the nose gear. I was
seated just aft of the right wing root hooked up to the communications
system so that I could hear what was going on and comment if
necessay. Paul Bennett brought the F-86 right up underneath the
right wing of the 737 so he could take movies out of the side mounted
camera, recording the position of the gravel ski as the nose gear
cycled. From a position right behind the wing root inside the 737
I was looking right down into the cockpit of the F-86, and I couldn't
believe how close Paul had brought the F-86 up under the wing of the
737. I felt like if I could reach out of the window I could
almost touch the F-86. I bet there wasn't more than 10 feet, if
that much, between the two airplanes. The gravel ski positioning
system worked fine and Paul got some good pictures of the gear and ski
as the nose gear cycled. When the testing was over, Paul just
dropped straight down some, rolled over onto his back and did a split S
away from the 737. What a view I got of a classic airplane.
I will never forget the sight of that airplane flying so near and then
falling away in a split S. What a sight for any airplane buff.
Seems like everytime I read one of your e-mails, old memories from both
my Boeing and flying days as a light plane driver come rushing back.
Take care and keep bringing back those old memories.
Initially known as the P-80C, the trainer variant flew better than its
single seat cousins. Powered by an Allison J33-35 single-shaft,
turbojet engine with a thrust rating of 5,200 lbs, the improvements to
the trainer meant it climbed faster, cruised better and overall was
slightly faster than the fighter version. In May 1949, the designation
for the aircraft was officially switched to T-33.
The RCAF’s introduction to the aircraft followed two years later, when
the first of twenty Lockheed built T-33As were delivered on loan. The
aircraft was designated by the RCAF as the Silver Star Mk 1. This first
batch was followed by a second loan of ten more aircraft. On September
13, 1951, Canadair signed a license agreement with Lockheed to build
T-33 aircraft for the RCAF.
I have received a lot of questions about engines - well, it's a long, long story! Here's a little bit.
The XP-80 was designed and flew with the Frank Whittle derived UK
engine, to be built under license in the U.S. Several
manufacturers were involved. But actually, Kelly Johnson's intent
was to power it with a much better Lockheed designed engine - an
in-house axial (straight-through) design from Nate Price, in lieu of
the British centrifugal flow design. As hard as it is to believe
but Lockheed actually had TWO geniuses on the payroll, for in addition
to Kelly, Nate Price was there on the engine side.
Nate Price and his proposed axial flow turbojet engine for the XP-80 with Kelly Johnson
If it's hard to believe that Lockheed had two geniuses working, it's
even harder to believe that the U.S.A. could win the War with the legal
neanderthals working in Washington D.C. For, at the same
time the War Dept was urging Lockheed to work faster on developing
their jet fighter, the Justice Dept was suing Lockheed for violation of
anti-trust laws. You see, this was a fallout of the Boeing
anti-trust break-up in the early 1930s, when Boeing was forced to
divest United Aircraft (Pratt & Whitney) and United Air Lines, and
it became illegal for an airframe company to also manufacture aircraft
engines. As a part of the settlement with the Justice
Dept., Lockheed agreed to sell all their engine design stuff - which
they did. They sold Rice's axial flow engine materials to a
Burbank machine shop named Menasco (which became a major landing gear
manufacturer), and all of the brilliant engine design work died a slow
death. As Shakespeare once famously wrote - "First thing, kill
all the lawyers"!!!
The Canadair built version was powered by an up-rated Nene 10 engine
licensed by Rolls Royce and supplied by Orenda Ltd. Once in production,
the aircraft was designated T-33 Silver Star Mk 3. Initially, the RCAF
ordered 576 aircraft, but eventually a total of 656 would be delivered
between 1952 and 1959.
The Allison J-33 Engine
The J33 was originally developed by General Electric as a follow-on to
their work with the designs of Frank Whittle during World War II. Their
first engine was known as the General Electric I-A, but after major
changes to adapt it to US production and to increase thrust, it started
limited production as the I-16 in 1942, the 16 referring to its 1,600
lbf (7.1 kN) thrust. Full production started as the J31 when the United
States Army Air Forces introduced common naming for all their engine
Along with the I-16, GE also started work on an enlarged version, known
as the I-40. As the name implied, the engine was designed to provide
4,000 lbf (18 kN). Apart from size, the main difference between I-16
and the I-40 was the combustion system: the I-16 had ten reverse-flow
cans, whereas the I-40 had 14 straight-through combustors. The
development cycle was remarkably rapid. Design work started in mid-1943
and the first prototype underwent static testing on 13 January 1944.
Rolls-Royce Nene Engine
The Nene was designed and built as a result of an early 1944 Air
Ministry request for an engine of 4,200 lbf thrust, and an engine was
schemed-out by Stanley Hooker and Adrian Lombard as the B.40. In the
summer of 1944 Hooker visited the US and discovered that General
Electric already had two engine types, an axial and a centrifugal, of
4,000 lbf thrust running. On returning to the UK Hooker decided to go
for 5,000 lbf of thrust and, working with Lombard, Pearson and Morley,
a complete redesign of the B.40 resulted in the B.41, later to be
called the Nene.
The double-sided impeller was 28.8 inches in diameter, compared to
20.68 for the Derwent I, to produce an airflow of 80 lb/s, while the
overall diameter of the engine was 49.5 inches. A scaled up Derwent of
the same power would have had a 60-inch diameter. The compressor casing
was based on Whittle's Type 16 W.2/500 compressor case which was more
aerodynamically efficient than that on the Derwent but also eliminated
cracking. Other design advances included nine new low
pressure-drop/high efficiency combustion chambers developed by Lucas
and a small impeller for rear bearing and turbine disc cooling. The
first engine start was attempted on 27 October 1944. A number of snags
delayed the run until nearly midnight, when with almost the entire day
and night shift staff watching, an attempt was made to start the
engine, without the inlet vanes, which had not yet been fitted. To
everyone's dismay the engine refused to light - positioning the igniter
was a trial-and-error affair at the time. On the next attempt, Denis
Drew unscrewed the igniter and as the starter motor ran the engine up
to speed, lit the engine with an oxy-acetylene torch. The engine was
run up to 4,000 lbf and more, and a cheer went up around the assembled
personnel. Upon Hooker's arrival next morning, and informed that the
inlet vanes had been fitted during the night, Hooker was satisfied to
see the thrust gauge needle registering 5,000 lbf, making the B.41 the
most powerful jet engine in the world. Weight was around 1,600 lb.
The Nene was based on the "straight-through" version of the basic
Whittle-style layout, with the flow going directly through the engine
from front to rear, as opposed to a "reverse-flow" type, which
reverses the direction of air flow through the combustor section so
that the turbine stage can be mounted within the combustor section;
this allows for a more compact engine, but increases the combustor
pressure losses which has an adverse effect on engine performance.
Less thrust is generated with the same fuel flow.
The Nene has a fascinating history, serving as the basis for derivative
engines powering numerous airplanes in the UK, USA (F9F Grumman
Panther), and Russia (MIG-15) - the Brits sold the Russians 20 engines
with the stipulation they "not be used for military purposes" - the
stupidity never ends. It was license built in Canada by Orenda. Much more info here:
See details on the CF-86 Orenda engine here: https://en.wikipedia.org/wiki/Avro_Canada_Orenda