john.r.davies Posted November 3, 2012 Report Share Posted November 3, 2012 I was going to make the same point as Mick, that a windscreened car has a high pressure area at the bottom of the 'screen, that can drive the air into the cabin. Not there of course, if aeroscreens fitted, alowing the 'extractor' function of a rear bonnet lift as described by Peter. Moreover the air there is slowed down (hence the high pressure), and anyway, recovery of the energy of moving air to impel it into a duct is very difficult. A simple scoop is useless. It took the NACA duct to collect air effectively from over a panel. Which shows the aerodynamic ignorance that prevailed at the time, not only that these scoops were fitted to TR4s, but they went on fitting them, for instance to the LeMans Spitfires. http://jmcracing.online.fr/article.php3?id_article=192&artsuite=4 The roof vents fitted to many rally cars nowadays are extractors, that depend on the Venturi effect of low pressure free air moving past a vent to draw air out of the car, a different aerodynamic kettle. John Quote Link to post Share on other sites
BlueTR3A-5EKT Posted November 3, 2012 Report Share Posted November 3, 2012 Now let us look at where the TR7/8 race car engine air intake for carbs is situated....... Quote Link to post Share on other sites
john.r.davies Posted November 4, 2012 Report Share Posted November 4, 2012 Please explain, Blue? Quote Link to post Share on other sites
BlueTR3A-5EKT Posted November 5, 2012 Report Share Posted November 5, 2012 Sorry off topic Quote Link to post Share on other sites
alan atkinson Posted November 5, 2012 Report Share Posted November 5, 2012 (edited) I have one on the 250 shell. Or at least the scoop part is on there. It is surprisingly poor quality. We decided to find something a little more attractive than chicken wire for the grille. The fender cut outs were cheaper to reproduce locally - I bought the grilles though and they too look like a 5 year old with a Dremel made them. I suspect though that this being for function not form that the originals weren't pretty either... Those who haven't seen it may find this of interest http://shell-4000-rally.org/4000_web/1964/pdf/1964_TSOA.pdf Edited November 5, 2012 by alan atkinson Quote Link to post Share on other sites
stuart Posted November 5, 2012 Report Share Posted November 5, 2012 The original wing (Fender to you Alan) grills were cut down out of Herald grill sections so they wouldnt have been too pretty to start. Stuart. Quote Link to post Share on other sites
alan atkinson Posted November 5, 2012 Report Share Posted November 5, 2012 (edited) I actually knew that. What I'm talking about is the finish on the holes that make up the grille sections. Let me dig out a picture and you'll see what I mean. Edit: Edited November 5, 2012 by alan atkinson Quote Link to post Share on other sites
stuart Posted November 5, 2012 Report Share Posted November 5, 2012 Hmm yes see what you mean. Im pretty sure original Herald grills werent that bad. Stuart. Quote Link to post Share on other sites
alan atkinson Posted November 5, 2012 Report Share Posted November 5, 2012 They look worse close up. Like the holes were hand cut. Quote Link to post Share on other sites
Graham Robson Posted November 5, 2012 Report Share Posted November 5, 2012 (edited) The scoop was used on my 'works' TR4s - 3VC/4VC/5VC/6VC - because we dumped the hinged flap and gismos (we also dumped the heater on events like the French Alpine and the Liege-Sofia-Liege) to save weight/complication. Like the standard hinged flap, it was purely to collect fresh air, and there was no tendency for engine bay fumes to get in to the cockpit that way. Like the front wing/engine bay vents, the scoop was there for a purpose, not for decoration. AAGR Edited November 5, 2012 by Graham Robson Quote Link to post Share on other sites
Alec Pringle Posted November 5, 2012 Report Share Posted November 5, 2012 Skip fodder, Alan. Meanwhile I remember navigating in a pal's TR4 long ago, given that there was no budget to make it quicker the obvious alternative was to make it lighter, which we did fairly comprehensively. One surplus weighty item was the heater assembly, removal of which did rather reduce the potential demisting capability - not that one always required demisting capability, given that the windey windows and mechanisms had also been ditched along with the hood and frame, and the carpets (to let heat in). We'd have skipped the windscreen in favour of aeroscreens, but the scrutes didn't exactly take to the suggestion. The spare wheel and tools went too, which concentrated one's mind on mechanical preparation, Nevertheless, on occasion it was a pain. Therefore a scoop modelled roughly on old piccies of the works cars was fabricated (I use the term fabricated loosely, it was beaten out of an old baking tray), on the basis that the works chappies might just have known what they were about. The resultant airflow through the vacuum cleaner hoses adapted to a ventilation system increased significantly, sufficient to demist adequately despite the lack of fan assistance. I do appreciate that aerodynamic theory might not have sat comfortably with that minor achievement, but we were more concerned 40 years ago with what worked, the hows and whys were irrelevant, suck it and see. Cheers Alec Quote Link to post Share on other sites
alan atkinson Posted November 5, 2012 Report Share Posted November 5, 2012 Well weight reduction wasn't really an issue here. The builder actually made a me scoop that allows me to retain the flap hidden behind it. Wonder if I can get a herald grille... Quote Link to post Share on other sites
stuart Posted November 6, 2012 Report Share Posted November 6, 2012 Wonder if I can get a herald grille... Here you go Al. http://www.ebay.co.uk/itm/1964-Triumph-herald-grille-in-great-condition-Other-parts-available-/181006000039?pt=Motors_Car_Truck_Parts_Accessories&hash=item2a24cc5fa7 Stuart. Quote Link to post Share on other sites
roy53 Posted November 6, 2012 Report Share Posted November 6, 2012 Have today just seen a 4 under construction which had a perfect answer,the lid was in a fully open position and held up or infilled with a fine mesh grille. This is a concourse standard car and it looked spot on. ROY Quote Link to post Share on other sites
Chilliman Posted November 6, 2012 Report Share Posted November 6, 2012 Alan, For comparison purposes - here are a set of originals I bought recently - like Stuart says they look a lot more uniformed than the ones you posted. Regards John Quote Link to post Share on other sites
alan atkinson Posted November 10, 2012 Report Share Posted November 10, 2012 Here you go Al. http://www.ebay.co.uk/itm/1964-Triumph-herald-grille-in-great-condition-Other-parts-available-/181006000039?pt=Motors_Car_Truck_Parts_Accessories&hash=item2a24cc5fa7 Stuart. Thanks. I'll see how they look when they arrive next week Quote Link to post Share on other sites
wayne taylor Posted November 10, 2012 Report Share Posted November 10, 2012 Sorry - if I've missed something: Can I confirm that the flap need to be OPEN to improve/assist cockpit heating? If I leave it open permanently with the mesh infil as suggested above - will this be long term detrimental? Many thanks WT Quote Link to post Share on other sites
Badfrog Posted November 11, 2012 Author Report Share Posted November 11, 2012 Sorry - if I've missed something: Can I confirm that the flap need to be OPEN to improve/assist cockpit heating? If I leave it open permanently with the mesh infil as suggested above - will this be long term detrimental? Many thanks WT Wayne, I confirm. Tested it again yesterday going up north (of France): open the flap and here comes the heat. No need to use the fan, car speed does the trick. Close the flap? No heat. Badfrog Quote Link to post Share on other sites
john.r.davies Posted November 11, 2012 Report Share Posted November 11, 2012 Badfrog, This was a difference from a scoopless previous? Ho-hum, aerodynamic theory goes back to the drawing board. John Quote Link to post Share on other sites
Badfrog Posted November 12, 2012 Author Report Share Posted November 12, 2012 John, No, I don't have an airscoop. Just the standard flap with a good rubber trim. It's nice to have warm feet in November when your ears turn to icicles. Badfrog Quote Link to post Share on other sites
RogerH Posted November 12, 2012 Report Share Posted November 12, 2012 Hi Wayne, the only problem with the flap being open ALL the time is if it is raining and the plenum drains are not too efficient. You will eventually rust your plenum sump into a lace curtain, keep your drains clear. Hi JF, my standard flap helps with the airflow but the fan does improve it signifcantly. Nothing wrong with blue ear lobes - very punkish. Roger Quote Link to post Share on other sites
Badfrog Posted November 12, 2012 Author Report Share Posted November 12, 2012 (edited) Hi Roger, The fan doesn't change much. Either its motor is dead or I'm driving too fast. Nevermind, I'm now about to drive a closed car with surrey and all (Milady de Winter). And Austerlite doesn't even have a flap. Not even a water pump or a heater. Talk about punk and gothic, my daughter is in charge here. With all that steel, I couldn't even raise my head to face the road. Badfrog, your pre-war amphibian for now Edited November 12, 2012 by Badfrog Quote Link to post Share on other sites
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