Hot Air Balloon Calculator

by paulftw

HTML

<script src="//code.jquery.com/jquery-2.2.2.min.js"></script>
Lifting force (kg): <input type=text id=force value=1 />

Grams of butane: <input type=text id=butane_needed readonly />

JavaScript

var vol = 3.91; // m3 - volume needed to provide 1kg of lift at 100C

var butane_mass = 0.1; // kg

var butane_energy = 49 * 1000; // kJ/kg

var air_heat_capacity = 1.3; // kJ / m^3 / C

var delta_T = 80; // C


$('#force').on('keyup change', function() {
	console.log('xx');
	var force = parseFloat($('#force').val());

  var energy = delta_T * air_heat_capacity * vol * force;

  var butane_needed = energy / butane_energy;

	$('#butane_needed').val(Math.round(butane_needed * 1000 * 10) / 10);
});

$('#force').change();