Rolls-Royce Archives
         « Prev  Box Series  Next »        

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).
Technical note comparing different aircraft engine nacelle setups, with additional details on hydraulic tappets, clutches, and engine dimensions.

Identifier  ExFiles\Box 173\2\  img204
Date  14th February 1934 guessed
  
HS.{Lord Ernest Hives - Chair}
lll.

Nacelle Set-up.
H.P. Required to drive at 200 M.P.H. for a 600-HP Engine.
% of Total Engine H.P. Absorbed by Propeller Itself and Cooling Installation.

1. Single Row Radial. Best N.A.C.A.Cowl
63 H.P.
10-1/2%

2. Conqueror with Oil Rad. & Glycol Radiator.
42 H.P.
6.8%
(true also for double row radial)

3. As 2 but with no radiator.
31.H.P.
5.15%

4. Water-cooled engine in wing. No rad.shaft drive to prop.
12 H.P.
2%

The % figures seem remarkably small but if the prop. efficiency is taken as 75% as it should be (1) is stepped up to 14% and the others correspondingly. These figures were out of a confidential report which has just been completed. Whether of any value or not I would rather they did not get circulated outside R.R. Ltd. It should be interesting to compare them with the 13 M.P.H. we got on the vapour cooled job.

HYDRAULIC TAPPETS.
Here is a copy of a letter from the Pierce-Arrow expert on our trouble but it applies only to the bottom tappet type of lash adjuster, I'm afraid, and not to the Cadillac type. However, it may interest you.

LONG CLUTCH:
Also copy from Long Clutch expert who was away when I called at the factory, and puts the situation with regard to necessary pedal travel very clearly.

LASALLE ENGINE SIZE.
This measures 30-3/8" from front of damper to flywheel back face. Here are some Cadillac motor sizes. I forget if I gave them to you before:

Starter Motor 4-15/16 Dia.
Length of field frame 7-3/16" 6 Pole.

Dynamo 5-1/16 Dia.
Length of field frame 8-3/16 frame. Straight Shunt.

Further particulars of Allison Engine:
5.5 x 6 1160 lbs. Gear Red. 2-1 C/R 5.8 Length 94"
Max.output 1000 HP at 2800 RPM. Normal Output 750 HP at 2400 RPM
  
  


Copyright Sustain 2025, All Rights Reserved.    whatever is rightly done, however humble, is noble
An unhandled error has occurred. Reload 🗙