<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META content="text/html; charset=US-ASCII" http-equiv=Content-Type>
<META name=GENERATOR content="MSHTML 11.00.9600.18666"></HEAD>
<BODY id=role_body style="FONT-SIZE: 10pt; FONT-FAMILY: Arial; COLOR: #000000"
bottomMargin=7 leftMargin=7 rightMargin=7 topMargin=7><FONT id=role_document
color=#000000 size=2 face=Arial>
<DIV>Hi Mike, </DIV>
<DIV> </DIV>
<DIV>A good question that no-one else has asked and which isn't in any of the
data I've released!</DIV>
<DIV> </DIV>
<DIV>Wind tunnel testing can be at any speed up to the maximum rating of the
tunnel. At the tunnel I used it was also possible to have the data
automatically calculated at a higher speed than the test speed.</DIV>
<DIV> </DIV>
<DIV>The answer to your question is probably at any speed above 50 mph with
increasing effectiveness at higher speeds. Why 50 mph? Well, at 50
mph I'm guessing the grip of the tyres is making a bigger difference than
the aero. I'm also guessing the lighter the Sprite/Midget the greater the
difference. Some of this may be in the book, eg: I didn't notice
front end pitch on my car when it weighed about 20 Kg more than it does
now. Put another way, the aerodynamic forces were the same when it weighed
20 Kg more but were simply less/not at all noticeable.</DIV>
<DIV> </DIV>
<DIV>Drag reduction is always most noticeable at top speed simply because it
allows a higher top speed. The lift reduction will probably be most
noticeable at about 80 mph upwards because that's when driving through my
'reference fast curve' I start to think about whether the car feels like it has
enough grip to press on to about 100 mph after which I get more cautious.
I'm guessing that when I drive my 'reference fast curve' the car will feel more
'planted' from 80 mph upwards and at 100 mph I'll feel a lot more confident to
proceed to a higher speed than was previously the case. Put another way,
at the present time I don't know what 30 lbs less lift will feel like other than
it will remove the pitching down at about 110 mph that it currently has.</DIV>
<DIV> </DIV>
<DIV>Regards</DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV>Daniel</DIV>
<DIV> </DIV>
<DIV>
<DIV>In a message dated 12/05/2017 20:17:53 GMT Daylight Time,
rrengineer.mike@att.net writes:</DIV>
<BLOCKQUOTE
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><FONT
style="BACKGROUND-COLOR: transparent" color=#000000 size=2 face=Arial>
<DIV>Out of curiosity, at what speed does it become effective?</DIV>
<DIV id=yui_3_16_0_ym19_1_1494612920481_101723 dir=ltr>Mike MacLean<BR></DIV>
<DIV id=yui_3_16_0_ym19_1_1494612920481_101695><SPAN></SPAN></DIV>
<DIV class=qtdSeparateBR><BR><BR></DIV>
<DIV class=yahoo_quoted style="DISPLAY: block">
<DIV
style="FONT-SIZE: 16px; FONT-FAMILY: times new roman, new york, times, serif">
<DIV
style="FONT-SIZE: 16px; FONT-FAMILY: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif">
<DIV dir=ltr><FONT size=2 face=Arial>On Friday, May 12, 2017 9:31 AM,
WeslakeMonza1330--- via Spridgets <spridgets@autox.team.net>
wrote:<BR></FONT></DIV><BR><BR>
<DIV class=y_msg_container>
<DIV id=yiv8237198986>
<DIV><FONT id=yiv8237198986role_document color=#000000 size=2 face=Arial>
<DIV>Hi List,</DIV>
<DIV> </DIV>
<DIV>My new boot lid has just been delivered. The lid is a new steel
frame, skinned in aluminium and incorporating a spoiler based on the design I
tested in the full scale wind tunnel. It's seen here placed rather than
fitted to my car for a photo before I get it painted. It weighs in about
230 grammes less than a steel lid without a spoiler but after painting I'm
guessing the saving will be about zilch. Short of my unexpectedly having
a large sum of spare money it will be several years/never before I can
have it tested in the wind tunnel. However, in the light of the 4 tests
I made with the 'mule' boot lid and spoiler its very likely to put 2 mph on
the top speed and reduce lift by 30 lbs at the rear.</DIV>
<DIV> </DIV>
<DIV>Regards</DIV>
<DIV> </DIV>
<DIV>Daniel</DIV></FONT></DIV></DIV></DIV></DIV></DIV></DIV></FONT></BLOCKQUOTE></DIV></FONT></BODY></HTML>