So now I am on a wire , and we go on.
The formula that Mr Daws describes is linear and asumes a load to be carried by the construction of the tire ( explanation I give to it) and the rest is logical pressure times surface story.
I contacted Mr Daws to ask for discussion about this and he provided me with usefull information in time.
One thing is how the official formula is determined, and next is partly my conclusion.
1928 the basic formula for diagonal tires was a aproaching formula determined by measuring a large number of different tires , and I assume they put a series of different pressures in it , and loaded the tire until it gave the deflection that it would have when Pr and maxload on it, and put it in graphics.
That graphics line gave a curve and not a straith line.
Also they probably did not go back to zero pressure , I think a range between 100% and 50% of Pr.
so this all made me conclude that there has to be a curve in the graphics because measurements dont lie.
This curve can be get by putting a power in the formula , and that is what the official formula has .
Mind there are 2 ways of calculating. one is to determine loadcapacity for a sertain pressure, the other one is calculating pressure for a sertain load.
I determined my own universal formula in wich, and a construction load ( Lc)as Mr Daws described formula , and a power as in the officiall used formula.
By picking the righ power and Lc , you can make the official formula's and that described by Mr Daws of it,
Lc is the load that is carried by the construction of the tire at the actual deflection .
X is the power used and I made a spreadsheet in wich you can put your own power and Lc to compare 3 different calculations and/or tires.
Determined by the article of Mr Daws that a power of 0,95 and an Lc % of maxload,depending on the Pr, then for 35 psi 6% and for instance 70 psi 3% , to give a save loadcapacity so the deflection of tire stays the same over the whole range of pressure /loadcapacity.
This link leads to a map on my One-drive ( former Skydrive) that belongs to my hotmail adress with same username as here. ( so jadatis) .
This map I specially made to put pictures and spreadsheets in to support my discussion with Mr. Daws.
A lot of spreadsheets with my own formula and at one tab the compare part and a little history of used powers in time.
That power thing is a bit dificult.
But power 2 means Squaire and power 1/2=0.5 means root.
Power 1 is the number itself. On sciencetific calculators there is a button X^y for it and ^ is the symbol for power
Example 3^2 = 3x3=9
ETRTO uses Lc zero and Power 0.8 for every kind of tire since decades.
TRA used to use for normal car tires/P-tires with Hight/Width division above 50% power of 0.5 even wich lead to to much deflection,But stepped over to the 0.8 power in 2006 saying it was for globally using the same system , but in real it was because 0.8 power is better .
Hope you now have an idea of why I allow myself to be as pigheaded to construct my own formula , because its saver.
Can be that I have to adjust it in time in its power and Lc , but I think my formula gives sooner to low loadcapacity then to high, wich is never wrong.
In next post I will give a picture of different calculations, to show what difference it gives and also a "on the road"methode.