A study of the Wright Whirlwind 200 hp J5 made me wonder if it could be matched to a Cessna 172 airframe.

Radials have the ability to run on much lower grade 50 octane gasoline and have great air-cooled reliability. The J5 can generate 200 hp at less than 2000 rpm.

But it was found these these engines burned far more oil than the Continental or Lycoming ones, with oil/fuel consumption ratios approaching that of 2 cycle mixtures.

For all the desire to save weight, the Spirit of St. Louis would have had to carry a considerable amount of oil to make the trip.

How much oil did Lindbergh take along, and where was it stored in the plane?

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    $\begingroup$ I read his book about the trip years ago. The oil tank doubled as the firewall and was quite large and IIRC it had enough volume to supply the engine for the 39 hour trip. When Lindberg arrived over Paris. he had more than enough fuel left to make it to Rome, and mulled carrying on for a bit, but decided that crossing the Alps at night was pushing his luck a bit too far and started to look for Le Bourget. $\endgroup$
    – John K
    Commented Jun 25, 2021 at 1:19

1 Answer 1


Source: http://www.charleslindbergh.com/plane/

This site has a diagram of the plane: enter image description here

And links to a PDF that states:

The 25-gallon oil tank was arranged between pilot and engine to as to act as a fire wall.

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    $\begingroup$ An oil tank as a firewall? Gutsy! $\endgroup$
    – ceejayoz
    Commented Jun 25, 2021 at 13:47
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    $\begingroup$ @ceejayoz - better than a gas tank. You can throw a lit cigarette into a pool of diesel and nothing will happen (well, the cigarette goes out). Oil is even harder to get to burn. $\endgroup$
    – Jon Custer
    Commented Jun 25, 2021 at 14:21
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    $\begingroup$ Plus a tank of oil, at least while it's full, will have a much larger thermal mass than any wooden board that would have been used in that era. I'm picturing a nice white blanket of woven asbestos fiber on the engine side, but most likely Lindbergh would have passed on that on weight grounds. $\endgroup$
    – CCTO
    Commented Jun 25, 2021 at 15:20
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    $\begingroup$ @JonCuster you can actually do the same with a cigarette in regular gasoline, though it's arguably more about how bad at cigarettes are at igniting vapours than anything else pubmed.ncbi.nlm.nih.gov/21605828 $\endgroup$
    – llama
    Commented Jun 25, 2021 at 20:23
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    $\begingroup$ @rclocher3 My significant other is a safety engineer for a petrochemical company. She demonstrated. There's plenty of demonstration available : youtube.com/watch?v=7soVqyGq4i4 $\endgroup$
    – Jeffrey
    Commented Jun 26, 2021 at 3:44

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