Bjorn’s Corner: Aircraft drag reduction, Part 7

By Bjorn Fehrm

December 01, 2017, ©. Leeham Co: In previous Corners, we looked at how the Wright Brothers understood the wing aerodynamics and aircraft control.

We now describe how the Wright cracked the third nut keeping them from manned flight, propulsion.

When they had mastered the design of effective wings and control of their gliders (see previous Corners), the Brothers now worked on finding an engine and a functioning propeller.

Figure 1. The Wright engine for its 1903 Flyer seen from the underside. Source:

To develop an aircraft engine

When the Wrights returned after their successful 1902 glider tests at the Kitty Hawk dunes of North Carolina (where the constant winds and the soft sand was ideal for their flight experiments), they knew the next project should be a propelled flight.

With the results from the wind tunnel tests, they could calculate how much power a gasoline engine should develop. They sent out letters to engine manufacturers asking for an eight-to-nine horsepower engine, which should weigh no more than 180lb (82kg).

There were no answers. Such an engine did not exist. With the experience of their wind tunnel tests (if they wanted something done correctly, they better do it themselves), they decided to build the engine themselves.

They were advised that Benz and Daimler made engines with aluminum blocks in Germany. All automotive engines in the US had cast iron blocks. The Wrights decided to make an aluminum-based engine using recent copper alloying knowledge, to get the required strength and stiffness for the castings.

Orville began building the engine in their bicycle shop with their mechanic, Charlie Taylor. They only had simple tooling (a lathe and a drill press) and worked from Orville’s sketches. The castings for the parts were made in a nearby foundry, Figure 2.

Figure 2. The cast parts ready for machining. Source:

Once supplied, Taylor machined them and started building the engine with other parts he’d made in the shop, Figure 3.

Figure 3. Different parts for the internals of the Wright Flyer engine. Source:

Though it was a simple engine, it was the first engine built specifically for an aeroplane.

By Spring 1903, the Wrights’ had a working engine, Figure 4.

Figure 4. Cut-away drawing of the Wright Flyer engine. Source:

It was a left canted engine with the following specification:

Cylinders: 4

Stroke: 4 in (10.2 cm)

Bore: 4 in (10.2 cm)

Displacement: 201 cubic in (3.3 l)

Horsepower:12 at 1,300 RPM

Ignition: Make-and-brake powered by low-tension (10-volt) magneto.

Weight: 180 lbs (81.6 kg)

Unique features: Aluminum block, no carburetor

For those wanting to learn more about the engine, here’s the link.

Propeller needed

With a working engine, the only missing piece was a working propeller. Propellers were not well understood at the time. The Wright’s had to make their most groundbreaking work when cracking this nut. We will discuss this in next Corner.

16 Comments on “Bjorn’s Corner: Aircraft drag reduction, Part 7

  1. In theory could they buy the FAA certified 767-2C basis for the “Frankentanker” and have it certified for pax.

    • not sure a wright flyer could hold up the weight of a 767 engine, much less withstand the aerodynamic loads at Mach 0.85

      would be fun to see someone try though….

      • The only way it would work would be to mount the flyer on TOP of the 2C engine. And then it would be a non starter (pun intended)

        Sorry Claes, me thinks you were commenting on the subscription title not the WB engine!

        • Yes, it belonged to the 767-300ER restart article, LHN does not yet allow editing your respones from typo’s like Aw Week does.

  2. The Wright Brother’s engine, fine as it was, was not the first engine built specifically for an airplane. That distinction belongs to the Manly-Balzer engine of 1903, used on the full-size Langley Aerodrome. The Manly-Balzer was a liquid-cooled 5-cylinder radial, and produced 52 horsepower for a weight of around 130 pounds (unclear if that was the dry weight or included accessories and oil and coolant water). That power-to-weight ratio was not bettered for many years. Unfortunately the Langley Aerodrome was a complete failure as an airplane (“slid into the water like a handful of mortar”) and the Manly-Balzer engine faded int obscurity.

    • Good Info:

      Article says Curtis tried to use it on a replica (so why not a regular aircraft?)

      Any explanation why others did not try to sue it?

      Is it possible the details are exaggerated and it did not work as advertised.

      It would not seem likely that it would be dropped when it appears to be vastly superior.

      Or is it one of those it looked great on paper and simply did not function?

  3. What always strikes me about the WBs, they were incredibly focused and unbelievably determined that went with their confidence in themselves. .

    How often does a pioneer build an entire technology from scratch?

    • Adding in the whole Flying tech has at least 4 of 5 sub techs to get the Flying part work.

      • Only 20 years after the invention of the modern bicycle. Boeing is busy buying up anything that might make such a leap.

    • From scratch ?
      The engines were ‘based on’ the automotive engines that existed at the time, and the principles of flight and even flying gliders had been around for some time.
      It goes for a lot of ‘technologies’ even now,a particular person draws it all together and makes it work. Its still quite an achievement.

      • Aluminium was a very avante garde material in 1903. I would be highly impressed if my local bike shop managed to produce an IC engine and wind tunnel today. Reading these articles has made me realise that the Wright bros did a lot more work than I had realised.

        • By the 1900s aluminiums time had come , foil was on the market in 1910. The real problem before that was the process from bauxite used large amounts electricity.
          It had gone from the 1860s when aluminium plates were seen as rare as gold.

          • I think you fail to realize that it was a mix metal and that is always a challenge.

            Not they did not invent the engine, but their was lite enough and powerful enough to do the job.

            Do you think any bicycle shop you care to name could do the same today?

  4. A few years ago I was working at Boise Airport.
    The airport has a replica of a Wright Brothers Glider.
    I was amazed at their understanding of control, for example the wing warping and rudders were coupled.
    Looking at this glider made me appreciate just how advanced they were.

  5. Bjorn,
    A minor correction for the caption of Figure 1.
    I think “2003 Flyer” should instead be “1903 Flyer”.

    Thanks for doing this series of posts. I’m enjoying them.

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