Escadrille Ecosse

Excellent result Hamish. Interested in seeing the engine doing it's damnest for Team Hamish Racing

No worries John. Enjoy yourself

We can see where it rained Well done Hamish. Excellent result.

Good grief no Roger I n every respect carbs are not as good and would have struggled terribly with the heat. Let alone giving you the excellent mpg. Nick's point about the amount of correction is probably valid and probably why your manual adjustment on the TR6 struggled Michael. I'm also wondering if at these extremes there may be some benefit in ignition timing adjustments. Don't know.

Garlic Tough wee beastie it would seem though

John sorry I copied your whole post rather than just the lazy tongs if those are surplus to requirements

Mine too. I have quite a lot of learning to do before heading down the MS rathole

Yup. This thread is interesting. https://support.spitronics.com/manuals/altitude-compensation/ A different ECU but shows there are ways and ways of applying barometric compensation.

Is the correction for fuel? ie 80% correction gives 80% fuel for equivalent load at sea level?

What size chuck(s) John? Do you know if these are still available?

Keep up the good work Hamish

Out of curiosity I have been reading some of the MS discussion on the topic. And I see what you mean. Having no experience of MS a lot of the programming conversation goes over my head BUT I suspect everyone is actually talking about the same thing - although confusing exhaust 'backpressure' with general ambient pressure reduction that affects the whole system - and the issue actually lies in how the correction algorithm(s) are working and/or interracting with the sensors. I am quite prepared to be shown to be wrong (when I get to this level of finessing with the Spitfire there will be plenty for me to get wrong) but my gut reaction is "ye cannae change the laws of physics Cap'n". Piston engine aircraft obviously have to deal with this issue and a couple of interesting articles here although they discuss carburettors rather than injection the requirement inside the cylinder is the same. Just the method of achieving that that changes (hence my suspicions on algorithms and sensors). http://www.theaerodrome.com/forum/showthread.php?t=31874 https://aviation.stackexchange.com/questions/59328/why-do-carburetors-tend-to-produce-richer-mixture-at-higher-altitude

Eh! 'Back pressure' may well go down but so does inlet pressure so that sounds like a complete load of guff to me. Altitude effect on inlet pressure can be significant whereas the effect compared to combustion pressure exhausting out of the cyclinder is trivial. All the sensible discussion I have seen is that fuelling, whether carb or injection goes down with altitude on account of the reduced cylinder charging. Carbs probably have a degree of self-management as the fuel feed rate effectively relies on the difference in pressure between the float chamber (venting to ambient) and pressure (or velocity - same thing Mr Bernoulli) at the jet. Injection on the other hand is only looking at the MAP sensor in isolation unless there is a second refence input from an ambient pressure sensor as the fuel supply is pump driven and effectively altitude independent.

Hopefully not if it's a pipistrelle Well rescued though and glad to see it is recovering nicely in the airing cupboard.

Said the man who just knocked up a complete injection manifold for the Vitesse

As ever other stuff needs to happen but both moulds now finished. D panels.. And vertical strengthener panels Stick them out the way for now and next job is to make a grill panel for the red pattern bonnet. Will make a copy off the steel one.

Hmmm. Quite. Hope you feel OK.

That was excellent Roger. And a most impressive mpg

Sigh.... At least it was just himself this time unlike other Iraq war fatalities.

Nice to see a happy ending nonetheless. Years ago I was up with the Loadmaster in the back of an RAF Hercules when the Paras were doing a low level exercise. 600 feet jump height on a static line. Talking with the guy about how it goes we got to the bit about the drill if the main parachute doesn't deploy. They all have a reserve but the answer was from that height by the time you realise there is a problem dealing with the reserve just gives them something to take their mind off the real problem before hitting the deck. Very much gallows humour. Nice day for a ride. Summer solstice ride for me tomorrow. i am going 'gravel' for the first time

Seconded

Hi Michael No offence was meant although my comment about different countries was more about the likely significant differences in 'cold' between yourselves and our sepic Isle and needing to know a lot more about your wee green beastie to be able to draw any valid conclusions. My point about the two moderns (if you can call a Caterham a modern) was actually the similarities in tyre deflection between the oldies and the state of the art. There is lots. And a couple more comparative data points to the discussion

Tricky. Could try looking at some US sites. They sometimes have suitable stuff not soid here. Although engine / electrical powered servos seem to be in vogue with them.

On the TR3 softer at the rear is probably the direction to go though for short sprints. However, back to my point about is the deflection of the tyre excessive based on a single data point? Without wanting to tell my Granny how to suck eggs but the only way to determine the correct tyre presssure for YOUR specific car and setup is to do some proper testing. An actual event is not the time to be doing this unless you already have some information to base your decisions on. Too stressful apart from anything else. What someone else is running on a different car with a different suspension setup, different engine characteristics, gearbox and final drive ratios, and a different driver on a different track/country can only be the very roughest of rough guides. So you need to test. On a track that you know well and can get some consistency so differences in the runs are more likely down to tyre pressures that 'other things'. Like spending the time, effort and money on the engine, suspension, etc you now need to do the same with the tyres. And if you are really keen then testing in the wet is the next step... grim. Couple of interesting examples which should give you pause for thought before simply adding more air And away from the rarified atmosphere of F1 to something very much nearer home. This is a Caterham 7. Recomendations for them are generally around 17-19 psi cold. Meant to add that the Caterham is also running a stiffer wheel to tyre width combination for thus level if deflection. You shouldn't try to compensate for a narrower wheel by adding more pressure as this will just lift the centre of the tyre and reduce the contact patch.