Ron, Take a look at this and see if you think this would be a good route to go with this. The time and subjective part of course is the number of landings needed to dial in the aircraft model.
Mfg reports that I am aware of seem to publish landing distances on both dry and wet surfaces using a std FAR approach (50' ht over threshold, 3 degree slope, published weight, and a Vapp=1.3Vso) - Once I have flown enough landings to determine "bp" (braking power) and "wbp" (wet braking power) percentages of the FG base "1" value that closely matches the published figures, put that in a formula including metar rain and snow. I don't know how to code it yet, but this is the formula in laymen terms. (built on a single weight basis) These are the parameters from a yasim fdm. gear/gear[1]/gear-friction-factor='x'(float), where as: x = BP-((BP-WBP) * (greater value, rain-norm or snow-norm or snow-cover)) gear/gear[2]/gear-friction-factor='x'(float), where as: x = BP-((BP-WBP) * (greater value, rain-norm or snow-norm or snow-cover)) /environment/metar/snow-cover='false'(bool) (assuming snow-cover=True to have value of 1, or no braking ability) /environment/metar/rain-norm='0'(double) /environment/metar/snow-norm='0'(double) Example : If : Test results for dry surface = .750 Test results for dry surface = .500 Metar Rain-norm value = .675 Metar Snow-norm value = .110 Metar Snow-cover value = false Then: /gear-friction-factor= .750-((.750-.500)*.675) So braking power applied to model: /gear-friction-factor=.58125 If it works then the file could be used for any model, once the wet-to-dry braking range is found, which as mentioned would be the most time consuming and somewhat subjective part. Peter On Dec 19, 2009, at 12:57 PM, Ron Jensen wrote: >> Simulating braking coefficients by limiting /controls/gear/brake-* isn't > the best way to go. For JSBSim aircraft static friction coefficients for > each gear can be adjusted on the fly by changing > fdm/jsbsim/gear/unit[*]/static_friction_coeff. I'm pretty sure yasim > has something similar... > > Peter Brown FG "Farmboy"
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