Standards

Power

All power figures use the manufacturer's official rating at the time of production. For aircraft, specifications reference manufacturer-rated thrust (lbs or kN), horsepower, max speed (mph or Mach), and service ceiling (ft).

1 PS = 0.9863 hp (SAE). The difference is approximately 1.4%. We display all figures as "hp" for readability, but European figures are metric PS unless otherwise noted.

Weight

All weights are kerb weight (DIN) in kilograms, measured with a full tank of fuel and all standard equipment but no driver or passengers. Where manufacturers provided multiple figures for different markets, we use the European DIN specification.

Performance

0-60 mph times are sourced from period manufacturer claims or verified independent tests (auto-data.net, manufacturer press releases). Top speed figures use the manufacturer's stated maximum. Where multiple sources conflict, we use the manufacturer's official figure and note discrepancies in the source links.

Engine Displacement

Displacement is listed in cubic centimeters (cc) using the manufacturer's official figure. Descriptive labels (e.g., "3.0L") are rounded approximations. The exact displacement is always available in the specifications table.

Production Numbers

Production totals include all variants of the listed model unless a specific variant is documented separately. For example, the W124 production total includes sedan, coupe, estate, and convertible body styles. Where a specific variant like the 500E is listed separately, its production total covers only that variant.

Model vs Variant

We distinguish between models and variants when they represent fundamentally different aircraft. A P-51D Mustang and a P-51H share a lineage but differ in engine, airframe, and performance envelope. They are documented separately.

When a variant represents a minor update (facelift, power increase, equipment change) without changing the aircraft's fundamental nature, we document the most representative version and note the variant range.

Year Ranges

Year ranges reflect the production period, not the announcement year. The start year is when the aircraft first flew. The end year is when the type was retired from active service or production ended.

Estimated Values

Market value estimates reflect approximate prices for good-condition examples in the current market. Ranges account for specification, condition, provenance, and market fluctuation. These are not appraisals. Actual transaction prices depend on individual aircraft history, documentation, and market conditions at the time of sale.

Sources

Technical specifications are sourced from manufacturer press releases (BMW PressClub, Porsche Newsroom, Mercedes-Benz Media), verified databases (auto-data.net), and official factory documentation. Every aircraft entry includes source reference links where available. When sources conflict, we note the discrepancy and default to the manufacturer's official figure.

Editorial Independence

Skies Heritage is an independent digital archive. No manufacturer, auction house, or commercial entity has editorial influence over aircraft selection, significance assessments, or heritage classifications. Our documentation reflects research and editorial judgment, not commercial relationships.