As this story of the Rohr 2-175 (71X) unfolds, Don Westergren and Richard will add to and
update this text. It is our intent to add as much information as can be found so there will
be a permanent record on the development of this marvelous aircraft.
Eventually, this story will be re-written to place the events in their proper order. After
completion with as much information as can be found, we intend to turn all of this over to
the
San Diego Air and Space Museum so it will be preserved and hopefully shared to all
those who are interested.

We would appreciate hearing from anyone out there that has additional information about
the Rohr 2-175 (71X). Thank you.

Rohr "Project 71X, model Two-175" was a two place ducted fan pusher delta wing airplane.
It was all composite construction aimed at low cost "molded" production. This first
prototype N62R was powered with a Lycoming 150 Hp engine using a special "high speed
cam" to be able to run at 4,000 rpm. It had foldable wings and tail. The original concept was
known as a Triphibian that refers to LAND-WATER-SNOW operations with the landing gear
and ski arrangement, and all being retractable in the end product.

A question has been asked about what happened to the Rohr prototypes.

The story of what happened to the prototypes is sad. Rohr built three airframes, the first
was designated as the Static Test, never meant to fly. A completed second prototype,
which Don Westergren flew had the Lycoming engine mentioned above with a wood
propeller. The third prototype was about half completed when the project was stopped.
The third plane was designated to have the Rohr designed turbine engine in it. Pictures on
this website show the Static Test plane with the Rohr turbine installed for ground runs only.

Shortly after the second test flight, Rohr got into financial problems with it's rail transit
business - mostly cost overruns building the rail transit trains for Washington DC. As a
result, Rohr came dangerously close to bankruptcy and "the banks" took over. New
management was installed at Rohr and the "old management" was thrown out. The airplane
project was a "pet project" of Bert Raynes, the "old CEO". As such, the three airframes, all
the engines, and all the engineering data, drawings, and pictures were stored away in a
locked area (Don had no more access to the files).

Some time later, the Aerospace Museum in San Diego Balboa Park was burned to the
ground by an arsonist. We don't know if the person(s) was ever caught, but the Museum
designated the then President of Rohr Fred Garry to be the Chairman of the Museum
Reconstruction Committee. Walt Mooney, who led the 71X project had gone back to work
at Convair, approached Fred about having Rohr donate the plane and info to the new
museum. The idea was not well received and two days later, all the airframes were cut up
at night and taken to the Otay dump. Only a few salvageable items like the engines, props,
instruments and wheels were salvaged. Don bought one of the props he had flown with
and the nose wheel from the flight plane (but the fairing had been cut off). Don also has
the Nomex Flight suit he wore on the first flight (it doesn't fit anymore). It is sad that the
political idea that "nothing good would ever come out of the old management" caused us
all to loose most of the information about the project.

The original members of the project are scattered, and most have past away. In 2003,
William F. Chana wrote his autobiography called "Over The Wing", published privately but
sometimes sold in the museum gift shop.

More............. Click here to go to page 2.
FRASER AERO TECHNOLOGY COMPANY  
Ray_Stits_Aircraft
Rohr 2-175 (71-X) Fan Jet
An original 1973 conceptual sketch by Walt Mooney.
The aircraft did not turn out totally as sketched. It was scheduled for a new gas turbine
engine being developed at the same time.
The right photo is Richard's Astro-Turf (zero tip clearance) seal
design that actually worked
The variable pitch propeller in
Richard's test chamber made from
steel. Drive was done in a vacuum as it
required only 1/10th  the horsepower,
which was supplied by a very small
(but noisy) hydraulic drive motor. The
strobe light used, visually stopped the
rotation so you could check the blade
pitch angles at various rpm's. The
wooden barrel skives are blade energy
reducers in case the aluminum  
propeller blades came loose. They
would otherwise have enough energy
to go through the 3/8" thick steel
chamber walls..... absolutely true.
The test gearbox
above is internal to
the vacuum
chamber. It was
unique because
the gear box and
propeller pitch
change hub are oil
pressure operated
(in the presence of
a vacuum). Perfect
seals required.
Schematic of the hydraulic pitch change mechinism for the
5 blade 71-X propulsor (propeller).
Copyright © 2000 - 2010 by Richard W. Fraser  All Rights Reserved
Testing was one of the biggest tasks for producing this aircraft for functionality, safety
and performance. A lot of money went into this effort, not only in hardware,
but for Rohr's dedicated employees  as well.
Click on the photos below to enlarge
The Rohr 2-175 (71-X) turbine engine, gearbox and 5-bladed propulsor. This
engine was originally scheduled for the aircraft, but the engine ran into
development problems and could not meet the production schedule. That is why
the experimental Lycoming piston engine was used instead.
Propeller / Duct configuration. Note the fixed stator vanes aft of
the propeller. They added considerable at cruise.

The aircraft ran away from it's Cessna chase plane on take-off.
Vacuum test chamber assembly showing propeller pitch change mechinism.

Picture No. 1 shows the slip ring assembly to the left of the propeller which relaid
instrumentation signals such as blade stresses. The special energy absorbing
skived wooden ring around the outside of the propeller is shown. It was there
because there is so much energy in the rotating aluminum blades, that if one let
loose, it would be thrown right out through the steel chamber. The wooden skived
ring reduces the energy to a level where that will not happen.

Picture No. 2 shows the aircraft type throttle and push/pull tube assemblies for
manually changing the blade pitch (with hydraulic assist).

Picture No. 3 shows the load cell push/pull tube going into the gear box.

Picture No. 4 shows the adapter plate attached to the vacuum chamber with the
hydraulic drive motor.
Click on th Link below to view / and join the RC 36" span Rohr 2-l75
ducted prop Foamie Model Group
http://www.rcgroups.com/forums/showthread.php?t=958304
Test pilot Don Westergren and the 71-X
A tribute to a very fine group of people who
had the vision and team spirit to do
something different

The Rohr 2-175 (originally known as the 71-X) was the vision of
several people and a visionary CEO Mr. Bert Raynes, who pushed
the design to completion.

The 2-175 accomplished it's first goal of a successful flight and if
the management of Rohr Industries, Inc. in Chula Vista, California
at that time had been given the opportunity
of placing the design into production,
the company would have made a well deserved profit
for many years to follow.
The 71-X in flight over the Holtville, California area
The 71-X in flight. The fields in the background were not really
blue. It's an old film photo that has been enhanced.
71-X in flight photo over the Holtville, California farm area. Note
the drag chute packet tucked under the duct.
A gracious thank you goes to Don Westergren for sharing these exclusive photos of the
71-X. Don was the test pilot for this wonderful aircraft. Both Richard and Don had the
opportunity of working together at Rohr Industries, Inc. on this project and also on Rohr's
2KSES Surface Effect Ship project which is covered in another section of this website.

Very rare photos indeed.  Although Rohr Industries, Inc. is now owned by Goodrich, the
remaining employees can be proud of the many accomplishments and Legacy that
"Pappy" Rohr has left behind.
And, yes, there was a proposed water born / snow ski version
being tested with single skis on each main gear and a single
reversed duck foot shape on the nose gear for take off and landing.
The only thing missing in this photo is Don Westergren sitting on
top of this 1/2 scale 250 lb. test model as it was being towed.
Don offered the variable weight needed to shift the C.G. for the
best tow attitude.

If the Navy helicopter pilot out of North Island, San Diego who flew
down to view this strange sport took any photos,
we would be glad to hear from you.
The "Two Don's," Herbst, passenger and manager of
manufacturing, and Westergren, pilot (with helmet) in the 71-X
An early morning photo of the 71-X. You can't see the crickets,
scorpions and tarantula spiders running around on the taxiway.
Don Westergren and the 71-X.
Note the white tape over the vertical tail folding hinge.
The 71-X undergoing a 110% static load. Note the test aircraft is
upside down for a positive load representation.
The 71-X and a drop test with Don underneath. He wasn't going to
let it get damaged...Ha Ha...just kidding.
Note the installation of the turbine engine for the test.
The 71-X with the turbine and 5- bladed propulser installed along side a
conventional Cessna. The 71-X was to be in competition with the
Cessna manufacturing company.
No comparison in designs or performance....old verses new.
Another photo of the 71-X and Cessna. Note the walls covered in canvas.
The walls were stacks of hay bales for deadening the sound during test
run-ups. You could walk around the outside and
actually hear very little sound. Amazing!
A later 3-views of the 71-X. The forward canard looking strake has been
removed and does not show in any of the flight photos shown. There was a
very good reason. Don Westergren was the test pilot and he said that he
had the final call on that protrusion.
Don's emergency escape route was to bail out in front of the wing leading
edge so as not to risk nearing the fan and duct in the rear.

The strake was removed. Compare this with Walt Mooney's
earlier 3-views below.
Walt Mooney's earlier 3-view showing the canard type strakes that were later
removed, as shown above. Note the dimensional differences (errors
possibly). The 20' span and 23' lengths are the correct dimensions. When
wings and rudder/fin folded, it fit into a standard 20' deep garage.
The 71-X on climb out using the wooden propeller and the  
experimental Lycoming high rpm engine.
The 71-X flying over the runway. Note the target painted on the
fuselage. That is the location of the center of gravety (C.G.)
of the aircraft.
A black and white photo of Don in the 71-X
  • The overall program was called Project 71X because it was started in 1971 as an "X" or
    experimental project. The actual name of the design was the "Two-175" for two place with
    a top speed of 175 mph (not Kts).

  • All altitude air to air photos were on the first official flight on October 14, 1974 at Holtville,
    California.

  • The second and final flight was on December 17, 1974 at Holtville, California.

  • All taxi tests were done at Holtville, California starting early Septemebr 1974 and included
    "first daylight under the wheels" on September 18, 1974. All subsequent taxi tests were
    under 35 foot altitude on straight passes down a 6,000 foot runway. This allowed the test
    pilot to get a feel for the aircraft in ground effect and a little out of it.
A Little Flight History
as provided by Don Westergren
Holtville Airport, the site of the flight testing. Click on the
photo to enlarge and read the average temperatures.
The Rohr turbine engine was a centrifugal compressor design with a single combustion chamber.
The photos above show the compressor diffuser efficiency test rig with a smooth flow bell mouth
entry and temperature thermocouple inlet monitoring. The combustion chamber can just be seen
attached to the rear of the white colored chamber.
Photos shown anti-clockwise are:
● Hydraulic oil supply control panel.
● Chamber oil pressure and temp.      
monitoring. Propeller blade pitch "T"
handle controls, writing table folded
down.
● Hydraulic power supply unit.
● Pressure / Temp. controls for the
oil pumb drive motor and internal
gear box lube.
● Back side of chamber showing
vacuum pump. oil return reservoir
and push / pull activation mechinism.


NOTICE:
This entire document  has
been made into a book.
Available soon...well it was
going to be until Don
wanted to add actual
construction photos that
he found. They will be in
included in the book.....not
on this website. They have
never been shown before.