From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Performance chart showing heat transfer versus air velocity for 20 x 55 x 2 1/8 AC.R.V. Cores with varying gap sizes.
| Identifier | ExFiles\Box 149a\3\ scan0163 | |
| Date | 9th April 1936 guessed | |
| NO. 340-10 EDCO EFFICIENCY 10 X 10 PER INCH EUGENE DIETZGEN CO. 20 x 55 x 2 1/8 AC.R.V. CORES CHART #3 B.T.U./MIN./SQ.FT.FA/100°F.T.D. VEL. FT/MIN. .020 GAP .040 GAP .060 GAP 2250 CFM .020 GAP REJECTS 1625 BTU 2250 CFM .040 GAP REJECTS 1530 BTU 2250 CFM .060 GAP REJECTS 1450 BTU | ||