It might be Ron, if the Merlin had a flat chamber. It actually used a pentroof.
The paired inlets are inclined, so the four-valve twin-plug chambers were an asymmetric kind of pentroof. In any case, with 6:1 CR, the head design wasnāt as critical as it would be for creating swirl and turbulence in a normally-aspirated engine. Which leaves roller rockers. Nice for avoiding side thrust on the valve stems and with hydraulic tappets especially, but screw and locknut rockers are entirely suited to the role as a war time field-serviced aeroplane rebuilt proactively according to hours used, so wear of stellite tipped valve ends would not be an issue.
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
42
and kirb , turbo compensate automaticly for altitude pressure changes,
without having a complicated gear setup, that can go sideways at the
wrong time!
That might be why GM decided to go the turbo route. However, designing a
turbo that wouldnāt fit in most of the aircraft fitted with the Allison engine was
a tactical error of the first water.
What they coulda done, I suppose, would have been to design both a turbo
and a supercharger. Then planes could be outfitted with whichever one fit.
There certainly was incentive to pursue such a development, considering
how poorly the Allison was regarded through WWII ā a shame, since it really
is an excellent engine.
This is the 2nd time in less than a month on 2 different forums that Iāve had to tell you to cease & desist with the racist & prejudice postings.
We agree on one thing: that we live in a different world today - one that is FUBAR - particularly the far fetched farcical soap opera reality that is playing out in a certain country at the moment. . . . . . . .
Iām not sure I understand what you are objecting to in ronbros post. Perhaps if you were to send me a PM detailing your objection it might be a bit clearer to me.
In the meantime, please edit your post to be less insulting to ronbros.
the stuff that I donāt agree with?
the stuff that you donāt agree with?
the stuff that nobody agrees with?
the whole thing?
technically it would be possible to configure the forum so that nothing anyone posts appears until it has been approved by all the moderators, unanimously. That would be tedious.
How about people just use a little bit of restraint?
I agree restraint. ā¦I asked about the v12ā¦since this is a jag forum thats what I thought we were talking about but we got into every thing else that was 12 cylindersā¦IT MUST BE A BORING WINTER. .HAHA
makes me wonder why they did NOT R&D the idea way back when, WW2 yrs!
for like you mention , packaging a big ass turbo when two small ones will do a better job!??
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
54
hey kirby, who made the 1st twin turbo engine??
No idea!
for like you mention , packaging a big ass turbo when two small ones
will do a better job!??
I do know that, around WWII and before, turbochargers tended to be great
big things. I suspect thatās because they didnāt spin as fast as they do now;
they had to generate boost from large diameter rather than high RPM.
Still, most of the packaging issues for turbos is the plumbing, not the turbo
itself. The P-47 Thunderbolt plumbing illustrates the situation in one of the
most successful aircraft of WWII:
And you thought a āremote turbochargerā was a new idea! You probably
thought intercoolers were a new idea, too.
Twin turbos might help there as well, though, in that ā for example ā you
might be able to plumb each bank of a V12 independently rather than having
to weave piping from both banks to meet at a single turbo.
On a P-38 Lightning ā powered with Allison engines ā the turbos are plainly
visible right up on top. These photos are of R/C models but they are
painstakingly accurate:
jeez kirby i was aware of the T-BOLT system back in the 1950s,( had an older brother in USAF,1948/49,)and it was summer of 1952 that my father,sat down with me, said if you want to make a powerful engine its got to be supercharged!!
i was trying to get 2 carbs working on my 1936 Ford roadster, LOL.
and saw 1st intercooler/aftercooler around 1966/67, on a race car! and shortly after started my quest about WATER INJECTION systems!
i,ll see if i can find WHO made the 1st twin turbo system, plenty of twin supercharger stuff! (very undependable).
of course today Ford has the ECOBOOST twin turbs, and thousands of others , as a matter of fact the latest HOT ROD magazine ,twenty of the fastest cars were ALL turbocharged!
let me add , do you know why the P47 T-BOLT had such a large chamber behind the pilot(beside the turbo) it was called a compression chamber(lot of volume), for short deck takeoff they would fill the chamber with plenty of boost by manipulation of engine timing and holding the brakes, reason just in case power dropped slightly they had a build up of pressure already available!
pilots were almost magic in those years, and now you know more about the subject!
Norm lutz built a very successful tunnel boat with one of his DOHC Jag. V12 engines, won a lot of races, set records and actually blew off a jet boat.Best, JW
My dad helped engineer the Allison 3420 (only 6 built)ā¦2 V1710ās running together through a common gear box. Henry Kaiser (steel co) had a couple he used in the Unlimited Hydroplane racing boats he raced at Tahoe and elsewhere. My dad helped Elmer Lenischmidt (crew chief mechanic) with keeping them runningā¦carbs were always a big problem. Bell King Cobras were raced in Harmon/Thompson trophy races, I think they were awesome machines but destroyed in accidentsā¦again my dad was assistingā¦long time ago, etc. Best, JW
1 Like
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
60
My dad helped engineer the Allison 3420 (only 6 built)ā¦2 V1710ās
running together through a common gear box.
