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).
Report condemning the 'Fisher' sparking plug due to design flaws, a doubtful patent, and high cost.

Identifier  ExFiles\Box 33\3\  Scan137
Date  30th May 1921
  
X1812-C.

To C.J. from Hs.{Lord Ernest Hives - Chair}

RE "FISHER" SPARKING PLUG.

It is quite impossible to give a report on a single sample plug. We should however condemn the Fisher Plug from the design. If it was submitted in the ordinary way, we should say that it is not worth testing. The very obvious fault with it, is the fact that they have an insulator which is the design to give a long length of insulation as a protection against leakage, yet, they fit the earth terminal in the plug in a way that there is only .1 of an inch which the current has to leak across and break down. We insist on any plug which we buy having at least .5 of an inch insulating surface.

One would anticipate that the only patent in this plug is the method of detaching the core. To us, this is a very doubtful advantage. We have got past the day when a motorist tolerates a plug which needs a lot of attention. Again, suppose that one accepts that a plug does need attention the operation of detaching the core on any plug takes only a small percentage of the total time to clean the plug. Most of the time is taken up in getting out the necessary tools and the actual cleaning operation, which, in the case of the Fisher Plug, would take longer than on the average plug.

The cost of the plug is also very high. The cost of the Champion detachable plug which is of better design is about 1/- trade price.

Hs.{Lord Ernest Hives - Chair}
  
  


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