WIX Archives

Yikes! How many hours a year do you plan to fly?????

Posted by bdk on Thu Apr 18, 2002 03:46:06 PM

In reply top Data Plate restorations v. "original" a/c posted by simon king on Thu Apr 18, 2002 12:41:24 PM

From a metal fatigue standpoint, I can only think of a few instances where warbirds are affected. I believe that B-17 wing attachments are one of those, but these aircraft were used for decades as fire bombers in a very corrosive environment and were flown aggresively (high gross weights and high G-loadings).

My experience has been that the only other fatigue issues with warbirds (or any prop aircraft) are usually in the cowling area and are from engine vibration and propeller slipstream effects. These are typically on secondary structure and cause cracks in cowlings, cowling support members, and nacelles.

Most other cracks or distortion are caused by induced damage (hangar rash, fuel trucks, pilots jumping from the cockpit to the wing, etc.) or corrosion.

Normally all these problems are discovered during aircraft condition inspections (annual inspection, progressive inspection, etc.) or noticed during routine maintenance.

Luckily, there are service bulletins, Airworthiness Directive (AD) notes, warbird groups (EAA, NATA, CJAA, etc.) and others to advise pilots and owners about these issues so that they can be inspected and discovered prior to catastrophic failure.

There are parts specifically designated as life limited components, but these are usually limited to helicopters and turbine engines which have very special requirements anyhow.

The bottom line is that most collectors fly their aircraft only seldom and store them in environments that would sustain the metallic structure indefinitely. A Mustang that flies even 50 hours a year is probably among the vast minority. It usually takes thousands (if not tens of thousands) of hours for these problems to manifest themselves.

: Presumably skins, ribs,castings and components etc all hav
: e a safe "life" after which it becomes unsafe to fly - I s
: uppose fatigue life is the correct term.
:
: Everything was built for a short life during WW2 - time wa
: sn't engineered into the design - it was more likely to be
: written off or shot down than reach the end of it's fatig
: ue life.
:
: I suppose what I'msaying is that will we ever reach that d
: ay when no "original" a/c are flying - and how far away is
: it.

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