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).
Numerical comparison of thrusts and power requirements for different fans at various speeds.
| Identifier | ExFiles\Box 75\3\ scan0055 | |
| Date | 17th December 1924 | |
| -2- Contd. To give the actual numerical comparison we will quote figures obtained at the higher of the two speeds suggested by you, viz. 1445 r.p.m. First, for the two fans compared on the road, the bench observed thrusts at this speed are :- For the modified standard 4.85 lbs. For the expl. fan 4.45 lbs. } 2 2" tip dia. and the powers required to drive are respectively :- For the modified standard .90 HP For the expl. fan .625 HP. At the same 1445 r.p.m. speed, the thrusts produced on the other fans are as follows :- For the standard EAC. 4-bladed fan 5.05 lbs. (This being actually larger than either of the two fans tested on the road, due to the larger dia.). For the first EFC. expl. fan (as reported in our EFC1/T17.12.24). 6.85 lbs. For the EFC. expl. fan best observed 7.0 lbs. } 23" tip dia. result to date. the power required to drive in these cases being For the standard EAC.4-bladed fan 1.32 HP. For the first EFC. expl. fan .98 HP. For the best observed EFC. expl. fan .965 HP. the larger powers in each case being due to the larger diameters. Inspection of the various curves indicates that a similar sort of comparison would be apparent with figures taken at the lower of the two speeds quoted, viz. 1175 r.p.m. Contd. | ||