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MG TD TF 1500 - Windshield effect on maximum speed

Hi Guys,

Just curious. What is the effect of folding (or removing) the windshield on maximum speed of a standard bodied T-Type? Does anyone have any data, experience or information?

Bob Schapel
R L Schapel

How fast do you want to go? I took my my TF up to 100 mph once just to see if it would do it. Make sure your affairs are in order before you do. :-)


I took a rock hit to the screen that would have nailed me straight in the face without it. I have never given a thought to driving with it down since.
L E D LaVerne

What? never road a motor cycle?
M Grogan TD23816

Sailing ship set for light breeze VS sailing ship set for storm.

Matthew.
M Magilton

I retired from two wheelers after an incident in my early 20's that removed a good portion of flesh from my palms.
L E D LaVerne

I have been frightened doing the "ton" twice - once on my Norton Commando Mk III on the 405 Freeway in Pasadena, and once in my Porsche 356SC on a long, straight road in agricultural Northern California. I backed off as soon as I saw that magic number, and was relieved to do so.

I've had a TF up into the high 80's (speedometer uncertainty...), and that was quite fast enough! It because very 'darty'.

Tom Lange
MGT Repair
t lange

Having escaped death for in excess of 20,000 hours supported by nothing but fast flowing air, I have no death wish to speed in an MG of 50s vintage!
P G Gilvarry

Ah yes, All very good points. I guess my question is not about an issue many have researched.

Bob
R L Schapel

Not many speedsters here then Bob
It would have to make a hell of a difference like on a bike if you put your flat hand up in the air at any decent speed the wind just blows your hand back round your head and a screen is a lot bigger than a hand
I can still remember quite clearly the first time I ran the midget without a screen, there was that much wind it lifted the eye hole in my helmet up past my eyes, Chin strap was a lot tighter second time out-----lol
willy
Actually, nothing to do with screens, but years ago I had a Mazda MX6 with a rear boot wing and at 80Ks onwards you could pull the boot release lever and there was nothing there, the wind was pushing the boot lid down into the catch hard enough at that speed to let it all just do nothing
Useless info but you've got it now
cheers

William Revit

Many years ago I tried it wearing only my regular eye glasses to deflect the wind. I got to about 30 mph and quickly decided that was enough. We have taken the grand kids for a ride with screen down, but that was only in a campground, at about 10 or 15 mph.
I don't know how the bikers and racers do it.
I do have a nice picture running the Indianapolis speedway.
Cheers, Byron.

JB Warwick

No lewss authority than "Road and Track Road Test No. F-2-53, MG TD and MG TDC (Mark II)", Feb. 1953.

"Performance: Both cars made their timed top speeds with the side curtains in place and the tops erected. Since there was only a light wind at the time, the averages were but little different from fastest one way runs. One timed run in the TDC was made with the top down and the windshield folded flat (but without benefit of a full length tonneau cover). The top speed was exactly the same."

Tom Lange
MGT Repair
t lange

I'd imagine it would be good for at least a couple miles per hour, all else equal. The top raised could possibly increase aerodynamics and reduce turbulence behind the car, so the R&T guys should have also compared top down and screen up for more useful results.

Lowering the screen would likely make a much larger difference if the front of the car wasn't the shape of a brick wall. Much of the air that would otherwise hit the screen goes right over it thanks to the highly vertical front end.
Steve Simmons

Thanks guys,

That is great input! The issue begs for more experimentation .... but perhaps we shouldn't.

Thanks Tom. That is very significant information from "Road and Track". Perhaps the only results from real testing available?

Enjoy your driving.
Bob Schapel
R L Schapel

Many years ago it was possible to buy a back draft accessory for these cars. Some modern soft top cars do have them of course, so I guess they must work to some extent. Anyone seen one on a T Type?
Dave H
Dave Hill

I saw a couple several years ago in Wisconsin.

L E D LaVerne

I thought that the backdraft screens were to keep the air from messing up you hair. I just wear a hat.
G D

I struggle to keep a hat on and have to have a secure (and uncomfortable) strap under the chin.
Dave H
Dave Hill

What hair? :-)
L E D LaVerne

Had my new MG ball cap hat on on a nice sunny day. Looked up at the clear blue sky and by by hat! Forrest TD/C/22679
Forrest Rubenstein

Forrest,

You need one of these.

http://www.ebay.com/itm/PU-Leather-Hat-Leash-Cap-Eyewear-Retainer-Strap-Hat-Clip-Holder-Cord-3pcs/132227695319?_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D1%26asc%3D20160908110712%26meid%3D5e3fd7790b0a40f29655abc36b710cf2%26pid%3D100677%26rk%3D1%26rkt%3D12%26sd%3D132179386479%26itm%3D132227695319&_trksid=p2385738.c100677.m4598

Jim
James Neel

That may save the hat from disappearing down the road, but you would be forever reaching around to put it back on. I think that I would rather lose the hat!
I still have hair.
Dave H
Dave Hill

Well, You could always go with one of these!



PJ Jennings

Yes, I’ve got one of those, but it somehow feels out of place without the Spitfire to go with it.
Dave H
Dave Hill


Flying helmets work great for us.

Jim

James Neel

I’ve only got some rudimentary aerodynamic knowledge but ‘form’ or ‘profile’ drag is a function of the projected area of the vehicle. With the screen up it would have to be a good 10% higher and be quite significant. (You can probably ignore the profile of the leather dome protruding into the slipstream) Parasitic drag is a function of things like the aerodynamic shape and surface texture and I think we can pretty well state that a T car in road form shares it’s aerodynamic properties with a house brick. The picture of the MG in the museum at Bourton-on-the-Water is a little more streamlined as is the speed record holder in the museum near Oxford which, from memory, was based on a T chassis.


C I Twidle

Bob
Perhaps you could fit the windscreen from your road car to your race car and compare at the end of the main straight at Phillip Island.
By the way - your TC looked great as usual last weekend at "The Island".
Peter (TC9356)
Peter Malkin

I guess the reduced area of the Brooklands screens must offer some benefit compared to the full sized screen, otherwise they wouldn't exist. I can’t think of another reason for fitting them.
Dave H
Dave Hill

Hi Peter.

You must have been looking at a similar car. I was in the program but had withdrawn my entry. It was the first time I have ever been a spectator at Phillip Island. It was fabulous as I was with a group which included three great photographers (two CAMS accredited and one ex professional) who knew all the best vantage points. It was a bit strange not being out on the track and I found myself timing cars to see where I would have been. That was a bit frustrating because in most races it probably would have been between Vern Schuppan (80s Lemans winner) in the 4.5 litre Lago Talbot T26 and John Bowe (ex Group A Touring Cars) in the 5.4 litre Carrol Shelby Allard J2X. They were really flying down the straights so must have been a lot less nimble in the corners. See you at Winton Historic Races?

Bob Schapel
R L Schapel

A couple of photos of the Carol Shelby Allard.

Bob, I was there on the Saturday and didn't see you. I was hoping you might have got on the track on the Sunday.

Kind regards,
Michael

M R Calvert

Second photo of the Shelby Allard.

Michael

M R Calvert

I just realised I have committed a faux pas with Mr Shelby's name - Carroll not Carol. Too late to correct the post.

Michael
M R Calvert

Well I don't know about you guys, but since coming to Florida I don't think I have had my hood up yet (2 years) Same for the windshield.
I have a baseball cap form LaVerne "Whitworth Nut Club" That was black but has now taken on a shade of brown as it is fading. The strap at the back when set right - keeps it on nice and tight and with only the Brooklands screen it stays on just fine. Not gone faster than 70 though.... :) Possibly need to take it off every now and again to let the blood circulate to the rest of my scalp - but have not lost it yet.
I also have a flying helmet and goggles - just in case.
A Palmetto bug at 60mph can really ruin your day.
It's just part of driving an MG.
IF it starts to rain or sprinkle - Just drive faster - so you don't get wet....... It also gets you home quicker

Rod
Rod Jones

Hi Bob
Age is catching up - I saw you in the program and went to say gidday in the pits but couldn't locate you. I was up on the banking and obviously mistook another TC for yours. I had a chance to speak to Vern Schuppan in his garage - a real gentleman and a real real car!
Will catch up at Winton.
Kind regards
Peter (TC9356)
Peter Malkin

This thread was discussed between 07/03/2018 and 16/03/2018

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