LogbookThe 450Logbook
Resources for
The 450 HP Stearman
Frequently Asked Questions
About a 1942 Stearman
Background: What this page is about. The Boeing Stearman model 75 (mostly known as simply the 'Stearman') is well known in the aviation
community worldwide, and is probably the most popular and easily recognizable
classic biplane in the world. The
Stearman is a classic pre-war design.
For the above reasons, I am often asked questions about the airplane,
and the processes and decisions I encountered along the way in making her
a complete and flying airplane once again.
This web page is intended to answer the questions I get from other aviators,
fellow Stearman restorers and pilots, and others just interested in vintage
and classic airplanes.
What is a Stearman and why did you want one? Designed and implemented as a very successful primary U.S. Army and Navy
trainer (Army PT17 and Navy N2S1/3), the Stearman "Kaydet" was the first
airplane that thousands of military pilots flew in preparation
for WWII. After the war, the aircraft became surplus and were sold for hundreds of
dollars, typically in the $500.00 to $800.00 dollar range. Cheap and plentiful,
the Stearman was known to also be one of the strongest and most capable
aircraft ever produced.
Surplus airplanes were purchased by fledgling flying schools, and
in large batches by crop spraying and dusting outfits, both in the
U.S. and other countries. The airplane is constructed of 4 wing panels, 1 center section
which connects the 2 upper wing panels and holds the gas tank, a fuselage with
tandem open cockpits, and an empenage of rudder, elevators, vertical fin, and
horizontal stabilizor. The landing gear is conventional tailwheel configuration,
and the main landing gear is made of telescoping tube arrangement, similar to
motorcycle forks.
Brakes are hydraulic, the rudder is controlled by cables, and the ailerons and
elevator are controlled with aluminum tubes riding on ball bearings.
. The 4 wing panels and center section have wood spars and ribs. The
remainder of the airplane is either aluminum or 4130 chrome-moly steel. All the
wings and about 75% of the fuselage are covered in fabric. The remaining fairings
and covers are fabricated from aluminum sheet.
The original motive power was an air-cooled radial engine of either
7 or 9 cylinders, generating 220 or 225 horsepower.
Stearmans, especially those fitted with (at one time) cheap and
plentiful surplus engines such as the Pratt & Whitney R-985 450 HP
were sent to work as agricultural dusters and sprayers carrying hundreds of gallons
of all types of chemicals in the front cockpit. Being such a good and
flexible workhorse saved the Stearman for its third incarnation as the
classic sport and pleasure aircraft it is today.
I have for as long as I can remember wanted to own a Stearman just for its
classic lines and looks. As I progressed as a pilot, I have come to need a
Stearman for its combination of its looks, and its sporting open-cockpit,
radial engine qualities. I enjoy old mechanical things immensely. When
opportunity knocked to have a Stearman I swung open the door.
Where do you find these and their parts? I found the project at my home airfield. The previous owner had been
collecting the parts in anticipation of making a complete airplane. I made
him a deal he could not refuse in cash. Cash is King, and will always be so.
Anyone can shop the same way, by visiting airports and hangars while they
fly from field to field, across the country.
Those who shop with credit cards in malls, answer want ads with checkbooks,
demand condition inspections, want guarantees and
return privleges, and so on should stay far away from classic mechanical things.
This cannot be stated too firmly.
This is 1930's technology and if you don't fully know what that entails in
every respect, you will be well served to stay very far away from owning
anything like it.
Similar projects can be found all over the world. Many people start projects
before finding they are in over their head. Some become available through death.
Others are a result of one restoration project acquiring enough parts to do
another. Of course, complete airplanes can be found in all the traditional places.
Like most popular classic machines, there are parts networks generated by
word of mouth amongst owners, and specialist suppliers stepping in to fill a need.
Rest assured that the local hardware store or Sears has absolutely nothing for
a Stearman, and even the local airport supplier used to Cessnas and Pipers will
have nothing for the old girl. You can find parts in several ways:
A successful restorer will encounter all the above. What did you begin with, and why are you doing all the work?
How are you qualified?
I started with a fuselage frame, landing gear, fuel tank, horizontal
stabilizor, a control tube, main gear wheels and brakes, and a few other
sundry parts. I also had a U.S. registration and N-number.
I started the work partly out of economic necessity, and partly out of desire to
do the job myself. I fully expected to have some sub-assemblies and/or processes
farmed out to others.
I am an FAA licensed airframe and powerplant (A&P) mechanic. When I started
on this project, I made certain that I was working with some very experienced
mechanics with Inspection Authorization (A&P IA). You not only need their
experience, but many items cannot be returned to service unless approved by
an IA mechanic. When I started this project, I was not yet a licensed mechanic,
but I had decades of aviation and mechanical experience.
I used the experience and training on this project as a basis for my qualification
to take the examinations for my A&P certificate. This is pretty unusual, as most
A&P mechanics take 2 or more years of full-time schooling before taking the exams.
Why did you choose a 450hp motor? What's involved in that?
Some of the decision was easy. The aircraft was last licensed with the 450hp
engine, so it wasn't really my choice. Returning the aircraft to its original
Continental motor would have required more work than staying with
the Pratt & Whitney R-985.
Even though the airplane had a 450 installed and approved before I got it,
the years of sitting as a derelict project had rusted away many small components,
and many of the modifications made in the 60's for agricultural use, simply were
not up to present day airworthiness standards.
With a standard configuration, you can follow blueprints and end up with an
airplane. With a 450hp conversion, you must do a good deal of engineering and
fabrication that has no manual or blueprints available. You must find other
aircraft and decide what will work for you, and how you will incorporate the
various changes. I spent a lot of time asking people with 450 conversions what
they did, and why, and would they do it again.
What are the special things about this airplane compared to a standard Stearman?
What did you make, and what did you farm out?
Basically, I did everything myself.
Perhaps 30% of the airplane is made from new parts provided from suppliers,
another 50% used and restored Stearman parts, and 20% fabricated from
either existing parts, or from scratch.
I have farmed out some sandblasting, prop governor overhaul,
and prop overhaul. I had the prop installation and weight/balance certification,
and final inspection work done by someone else.
I've had several hundred man-hours of labor donated by friends, and have had
at least 4 Stearman-knowledgeable A&P mechanics donate their helpful expertise
in supervising the work, and pointing out things here and there.
How long have you been at this?
The entire restoration consumed over 6,000 man hours. What covering system did you use?
I decided to use the Randolph Rand-o-Poly polyurethane system applied over Ceconite 101
fabric. I decided on the polyurethane system for two reasons:
There are other polyurethane systems. I just felt more comfortable with Randolph
products.
How does this airplane compare to a stock Stearman?
Other than looks, it weighs more, and flys 20 to 25
MPH faster. It performs aerobatics dramatically
better. It is placarded against intentional spins, and there are some other
number changes with regard to airspeeds and weights. I'll be posting some stuff
about flying qualities later.
What does it cost to fly?
The engine drinks 20 to 25 gallons per hour of fuel. Each engine is a
little different, but a big radial also drinks oil too. Yearly maintenance is
not as expensive as say a twin engine, or more complex modern aircraft. However,
a classic aircraft does need to be hangared and that is expensive.
All told, each hour of flight in this airplane can easily cost $150.
Would you do this sort of thing again?
In a heartbeat. I've acquired a Beech 18 project. This should run me well into retirement.
It is difficult for people who have not done this to understand how much of the
restoration is good management skills, in addition to craftsmanship. This can take a lot of time
that is not actually factored into the project. Projects fail and are for sale
all the time because someone could not manage themselves and the project.
Contact me if you have any questions or comments via
Stearman Email
My Stearman started life with me as a
basket of parts. I have now owned this aircraft far longer than anyone else
in its 60+ years of existance.
* Have a hefty checkbook balance, and locate the suppliers re-manufacturing parts.
* Have the talent and skill to make your own.
* Scrounge around. This too requires great skill and knowledge in
recognizing parts and where they might be hiding, and knowing their
value.
* Have a hefty checkbook balance and pay to have parts made.
In the standard
configuration, the Stearman is not underpowered, but does not have an excess
of power for aerobatics. I love to do aerobatics, and is the main type of flying
I enjoy. For aerobatics, the 450 Stearman is an outstanding performer.
Deciding to use the popular 450hp configuration meant:
* Special oil system.
* Customizing the engine controls.
* Decisions, decisions, decisions, on how or whether to do many optional things.
* 24 volt alternator system.
* Hamilton Standard 2D30 propellor hub and North American AT-6 blades.
* Beech 18 spinner, cowling, modified baffles (dishpan), and intake system.
* Vultee BT-13 oil cooler, oil tank, main wheels, control quadrants.
* Michel 760 channel radio, 2 place intercom, Narco transponder, ELT, electric tach's.
* larger 10.5" tailwheel, aluminum seats.
* Extruded aluminum Dusters & Sprayers foot rails.
* Custom oil cooler cooling scoop and ducting at left fuselage.
* Custom battery, oil cooler, associated mounts and mounting plates of .200 aluminum plate,
and inspection door located at baggage area.
* Automotive brake master cylinders.
* Fire extinguisher hatch re-located to right side to electrical inspection and
external power receptacle access.
* Twin exhaust and carb heat system from a Broussard.
* Custom designed engine control systems.
* Oil tank mounted in custom rack at baggage compartment area.
* Custom baggage compartment tray with removeable bottom for battery and oil
cooler access.
I repaired cleaned and painted all the old metal parts for the fuselage. I
constructed new wings after refurbishing and repairing all the metal fittings.
I purchased some pre-built wing ribs and spars, and cut and milled other
wood members as necessary.
I designed and constructed the electrical system. I did all the fabric
covering and painting. I installed the motor, and designed and fabricated
all the controls for it. I fabricated the cowling modifications, and various
other items as necessary.
I purchased some highly modified former duster parts (ailerons, center section)
and brought them back to standard configuration.
If I only had to assemble the airplane, and not restore any parts, it would
have been about 3,500 hours.
If I had been building a standard Stearman, I could have saved another 1,500 hours.
1. Speed of application. It is MUCH less labor intensive than any other system.
3. Ease of application. Temperature and humidity have little or no effect on
when and how the chemicals are applied.
Things you need to manage are
finding suppliers, sourcing hard-to-find parts, dealing with back-orders,
scheduling what to do while waiting for parts and supplies, evaluating options,
and knowing the laws and regulations. Some sub-assemblies and parts need to be
planned months ahead due to a number of factors like workspace availability, weather,
part availability lead-times. It can be a nightmare for the unsuspecting fellow
who is used to going to the lumber store and meeting up with a back-order on the
worst of days. You have NO idea!
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