J.A.W. wrote: ↑
Thu Jul 01, 2021 10:38 pm
.... Napier's fairly sophisticated castings for the Sabre's liquid cooled cylinder blocks ...
it has been said that ....
'Tony' Rudd (a 'Sabre-lover'), having designed the over-heavy and over-bulky H16 BRM engine ....
then complained that the big castings were much thicker and so much heavier than designed
the foundry made the patterns (thickness) to give a successful cast ie the design as BRM-drawn was uncastable
all this after the first design concept (2 camboxes and 6 camshafts) had been abandoned by BRM as uncastable
abandoned for the bulkier/heavier design with 4 camboxes and 8 camshafts and increased crankshaft spacing
(minimal crankshaft spacing being vital to CG height as the lower bank height was dictated by exhaust pipe run)
by 1955 the V16 BRM was reliable, very high-revving, and very powerful
(the 1954 2.5 litre F1 was decided before the 1952 WDC replacement of 'V16 friendly' F1 by F2 etc)
in late 1958 the FIA demanded 1.5 litre F1 from 1961
how didn't BRM even try an NA'd V16 ? (surely a winner from day 1)
... the hot ticket in 1965 was the transverse V12/central power takeoff Honda- BRM already had this in the V16
and btw ....
the 1966 '3 litre' F1 that (loosely) lasted 4 decades was announced in 1964 - and generous to the supercharged option
if BRM had used an NA version of the V16 1.5 litre from 1961 they could have also .....
won from day 1 in 1966 by reinstalling supercharging - eg initially a better-regulated 4 bar single-stage
(we might see turbocharging in F1 as a better-regulated 4 bar single-stage)
BRM had intended boost regulation by RR VG vanes (never implemented but interstage throttling later used instead ??)
in the 1968 SA GP demo they ran the V16 (with early type larger induction system) to 13000 rpm and c.780 hp
RR had said the V16 valve timing (less than 300 deg) and lift was a limiting factor (though safe to 190000 rpm)
NOTES TO SELF
BRM didn't stretch its 2.5 litre four for Intercontinental formula and 1961 F1 weight limit discouraged a related twin
Coventry Climax DID design an FPF ((94 x 90 2.5 litre) destroked to 94 x 54 for 1.5 litre !!
the point of the H16 was to use the 1962-5 winning 1.5 litre V8 innards
even without the other H16 design faults this was rather backing the wrong horse
enlargement (mostly by stroking) of 1.5s (originally for Ginther's US connections) showed the 1.5s rod ratio was wrong
ok the 64 valve H16 was maybe less ratio critical (also BRM and Weslake (related) 48 valve V12s) than 2 valve versions
but even without its faulty exhaust port divider design the 64v H16 wouldn't have beaten the DFV ?
(though at that time weight limits helped H16s by allowing them magnesium monocoques but not so DFV cars)
the H16 BRM /DFV Lotus 49 comparison I likened to a Sabre vs V12-power fighter plane comparison - 5 years ago !