Good morning,

would it be possible to add the calculation of takeoff distance (in addition to weight and balance) to Skydemon ?
A model could be this slide rule ("T.O.P. Comp" brand):

 http://www.primetab.com/flying/flying.topcomp.html
which can be bought here:
http://www.flightstore.co.uk/pilot-supplies-c1/flight-computers-c114/flight-computers-c115/takeoff-performance-computer-p5234

many thanks and best regards

Daniel

I wonder if we are confusing calculations and estimating.

For most light aircraft on grass IMHO it's always seemed more a case of good judgement and experience, it's not really a calculation at all - and it's usually short grass strips where the distance available is going to be most marginal. 

Many of the significant factors involved in estimating are very subjective - e.g. how damp or soft the ground is, or how long the grass is. A few weeks back the only option was to taxi along the runway to judge how soft it was and judge the impact .... (if you need 1700rpm to taxi you know it's going to be tight!) - there's no way to 'calculate' the softness of the runway.  

So whilst there could be a nice like calculator in SkyDemon with standard take-off factors etc - I do wonder if this is an area where as GA pilots we've been trained in an erroneous pursuit of spurious precision. The real point of the going through the take-off factors is not the number that pops out the end - but rather a checklist of factors to consider - if SkyDemon calculated the answer for you, you'd no longer be going through the checklist.