Napier Lion specific fuel consumption

[Pasoleati]

Harry Ricardo mentions in at least 2 sources that tests (by him?) run on a racing Lion from 1927 gave an s.f.c. of 0.32 lbs./hp/h. That an incredible figure. Easily beats all current SI engines.

 

[Nicknick]

I know who he was and I know that he wouldn't lie about fuel consumption, but this would be as low a modern direct injeted Diesel engines. I guess it was the indicated fuel consumption (still hard to believe), do you have a quote for that?

 

[Schneiderman]

Try these for a start

 

[Nicknick]

Well, this text isn't written by Sir Harry Ricardo himself and the fuel consumption is just an estimation based on the assumption that the engine alway run with full power, which vertainly didn't happen.

 

[Schneiderman]

Well Ricardo had little to do with the development of the engine and the numbers come from a presentation made by Wilkinson of Napier to the RAeS in 1928. And, yes, these are engines developed specifically for racing so they did run at full power for most of the time.

 

[Calum Douglas]

Cant comment on Ricardo`s figures, but I do have some actual Lion test data from January 1929, and when I do the simple
calcs, I get 0.48 lbs./hp/h. This is actually quite good (quite close to late 30`s aero engines), but not quite as staggeringly spectacular as 0.32 would be....

 

[Schneiderman]

The figures, from Napier bench tests in 1927, given by Wilkinson in R&M 1300 are 0.452 pt/BHP/hr. The fuel selected, after comparative tests, was 74.78% petrol, 25% benzole and .22 % TEL dope. The sg of the petrol was probably 0.67, as per the data given for the Golden Arrow speed record, then include the benzole and you are somewhere around 0.7, I guess. So, give or take, that is 0.4lb/BHP/hr. It looks like they may have improved on this for the Golden Arrow speed run in 1929

 

[Nicknick]

what makes 0.452 lb/BHP/hr to become 0.4 lb/BHP hr?

 

[Schneiderman]

Read it again. pt = pints

 

[Nicknick]

Benzol has a slightly lower gravimetric energy content than regular gazoline (about 4%), so if 25% of the fuel was Benzol, the gravimetric heating value is about 1 % lower than for regular gazoline. This doesn't make a big change when comparing the gravimetric fuel consumption per kwh (or BHP hr)

 

[Schneiderman]

I don't know what you are arguing about. I've given you the official figures as provided by Napier at the time. Whether you believe them or not is another matter entirely.

 

[Nicknick]

Ah that pint thing, imperial units are confusing me... In my mind, a pint is solely related to beer...

0.4lb/BHP/hr is still extremly low for an engine of that time!

 

[Nick Sumner]

Might also help to remember a UK pint is 20 oz while a US one is 16 oz.

 

[Nicknick]

 

[Schneiderman]

Might also help to remember a UK pint is 20 oz while a US one is 16 oz.

"a pint of water weighs a pound and a quarter" as we were taught at school

 

[Pasoleati]

One British pint is 0.568 litres.

 

[Nicknick]

I don't understand why are you still using this stuff? The Nasa and the American automotive industrie has switched to the SI system decades ago. The imperial system takes so much more effort for calculations and obscures all the logic of physics.

 

[Apophenia]

I don't understand why are you still using this stuff? The Nasa and the American automotive industrie has switched to the SI system decades ago. The imperial system takes so much more effort for calculations and obscures all the logic of physics.

All true but what's a few decades when the original documents being presented are almost 95 year old

 

[Nick Sumner]

I don't understand why are you still using this stuff? The Nasa and the American automotive industrie has switched to the SI system decades ago. The imperial system takes so much more effort for calculations and obscures all the logic of physics.

Yes, but try going in to any building supplies store in the US or Canada and ordering a '2.438 meter 5.1 by 10.2' for your framing.

 

[iverson]

I don't understand why are you still using this stuff? The Nasa and the American automotive industrie has switched to the SI system decades ago. The imperial system takes so much more effort for calculations and obscures all the logic of physics.

Yes, but try going in to any building supplies store in the US or Canada and ordering a '2.438 meter 5.1 by 10.2' for your framing.

And our civil engineers use the worst of both worlds: tenths and hundredths of a foot.

 

[Grey Havoc]

The Nasa and the American automotive industrie has switched to the SI system decades ago.

Though with Metric recently going in heavily for virtualisation and abstraction, one has to wonder if it is still a 'hard' measurement system.

 

[CJGibson]

I don't understand why are you still using this stuff? The Nasa and the American automotive industrie has switched to the SI system decades ago. The imperial system takes so much more effort for calculations and obscures all the logic of physics.

Yes, but try going in to any building supplies store in the US or Canada and ordering a '2.438 meter 5.1 by 10.2' for your framing.

And our civil engineers use the worst of both worlds: tenths and hundredths of a foot.

Don't mention the oil industry...