I believe the difference can be attributed to the TR-2's smaller radiator
opening.
That gaping maw on the 3 is pretty draggy. (I never should have sold my 2).
Terry Stetler
----- Original Message -----
From: Larry Young<mailto:cartravel@pobox.com>
To: Randall<mailto:tr3driver@ca.rr.com> ; Ken Gano,
home<mailto:triumphs@consolidated.net> ; jibjib@att.net<mailto:jibjib@att.net>
Cc: FOT<mailto:fot@autox.team.net>
Sent: Tuesday, July 15, 2008 10:44 AM
Subject: Re: [Fot] drag co-efficient and frontal area data for selected
Triumphs
I did a bit more on this stuff. The inconsistency was to do with the
power available and power required. The Autocourse article has
unreasonable values even though it states "Power at road wheels". I
don't believe a motor that dynos 90hp can generate 86hp at the road
wheels. Once scaled back, everything looks reasonable. It looks like Cd
= 0.48 for the TR2 and 0.58 for the TR3. In Jabekke trim, the Cd =
0.43, but with frontal area reduction CdA was 32% less. I don't know why
the TR3 should be that much different from the TR2. The only major
difference is that the TR3 test was for a hardtop car, while the TR2
tests were for a soft top with top and sidescreens erected. I'd think a
hardtop would be better. The numbers are supported by the top speeds.
The TR2 went slightly faster with 10 fewer ponies.
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