THEONE Posted August 11, 2011 Share Posted August 11, 2011 Boys does anybody knows how the total impulse is calculated ? Link to comment Share on other sites More sharing options...
mfstraydog1 Posted August 12, 2011 Share Posted August 12, 2011 There is a general equation for impulse. J= ImpulseF= Force averageDelta T= the change of time J=F x Delta T There might be a variation of this equation. All depends on what you want to find the impulse of. Hope this helps. Link to comment Share on other sites More sharing options...
r1dermon Posted August 12, 2011 Share Posted August 12, 2011 presuming you're talking about rocketry...a very rough calculation of "total impulse" or Ns, can be calculated by using a load cell, or a scale for a crude measurement, and multiplying the average impulse by the seconds for which the motor burns. assuming you have a flat thrust profile, it will be a lot easier than in an end burner... total impulse can be calculated using other variables as well...for instance, if you know the ISP of your propellent, you can calculate the total impulse based on that. to sum it up, presuming your motor has a completely flat thrust profile, and upon burning it on a scale, you come back with a 3 second burn, 2 seconds you get 80 newtons of thrust per second, and the last second you get 40 as it tapers off...your average thrust would be 66.6n, while your total impulse would be 200Ns. making your motor a very small H class motor. bear in mind, the ISP of most sugar fuel is higher than that of black powder...so your total impulse will be higher per gram of propellent...meaning a motor of the same exact specifications built with black powder, will not have as much total impulse as the same exact motor built with sugar. Link to comment Share on other sites More sharing options...
THEONE Posted August 12, 2011 Author Share Posted August 12, 2011 (edited) Ok i want it to find the class of the motor...Boys it is possible to find the pressure of the engine then you know the nozzle throat and the thrust ? Also something else, somewhere i read that the core must me always bigger than the nozzle, is this true or there is no problem ? Edited August 12, 2011 by THEONE Link to comment Share on other sites More sharing options...
r1dermon Posted August 12, 2011 Share Posted August 12, 2011 what are your thrust numbers? thrust in newtons x time=total impulse in newtons. from there you can determine what class your motor is. Link to comment Share on other sites More sharing options...
THEONE Posted August 12, 2011 Author Share Posted August 12, 2011 (edited) what are your thrust numbers? thrust in newtons x time=total impulse in newtons. from there you can determine what class your motor is. I have got a scale with max of 4,5 kilos but it terminated... Here is the motor 1.avi 1.bmp Edited August 12, 2011 by THEONE Link to comment Share on other sites More sharing options...
Recommended Posts