THEONE Posted July 14, 2011 Share Posted July 14, 2011 (edited) Lately i have fount this page and it seems really interesting...That i want to ask is if we can find any program that it calculates the KN Edited July 14, 2011 by THEONE Link to comment Share on other sites More sharing options...
anapogeetoofar Posted July 14, 2011 Share Posted July 14, 2011 Go here: LINK Its at the bottom of the page as "batescalc" For more advanced users: LINK This is what I use. Link to comment Share on other sites More sharing options...
THEONE Posted July 14, 2011 Author Share Posted July 14, 2011 (edited) Go here: LINK Its at the bottom of the page as "batescalc" For more advanced users: LINK This is what I use. My friend the second one i dont know how it works... Also at the BurnSim program, i havent got to choose the propellant... Edited July 14, 2011 by THEONE Link to comment Share on other sites More sharing options...
TigerTail Posted July 15, 2011 Share Posted July 15, 2011 Batescalc looks really interesting. What Kn should we aim for while making KNSU or BP(standard) motors? Is Thrust ∝ Kn? Previously I have seen flat thrust-time graphs for bates grains. Link to comment Share on other sites More sharing options...
r1dermon Posted July 15, 2011 Share Posted July 15, 2011 http://nakka-rocketry.net/th_pres.html all you ever wanted to know. Note, kn.is calculated using equation 12. You'll need to read and understand the whole page in order to solve though. Welcome to rocket science! Link to comment Share on other sites More sharing options...
TigerTail Posted July 15, 2011 Share Posted July 15, 2011 Grrr... It seems too intimidating for me to even try to solve and understand all that. Moreover I guess I won't get it even if I try Isn't there a short answer for my questions Link to comment Share on other sites More sharing options...
r1dermon Posted July 15, 2011 Share Posted July 15, 2011 the reason the thrust is flat in a bates grain design is because of the nature by which it burns. the surface area is designed to stay fairly constant as the motor burns. thats the basis for the grain segmentation. as with everything in rocket design, this is optimised for efficiency. Link to comment Share on other sites More sharing options...
THEONE Posted July 15, 2011 Author Share Posted July 15, 2011 Grrr... It seems too intimidating for me to even try to solve and understand all that. Moreover I guess I won't get it even if I try Isn't there a short answer for my questions You are very lucky because you know very well English if i were you i would read it till tomorrow morning... but i can not understand that it says !!! Link to comment Share on other sites More sharing options...
TigerTail Posted July 15, 2011 Share Posted July 15, 2011 So since throat area is constant, that does mean Thrust ∝ Kn. Right? Link to comment Share on other sites More sharing options...
THEONE Posted July 15, 2011 Author Share Posted July 15, 2011 the reason the thrust is flat in a bates grain design is because of the nature by which it burns. the surface area is designed to stay fairly constant as the motor burns. thats the basis for the grain segmentation. as with everything in rocket design, this is optimised for efficiency. What about a case bonded design ? Here the thrust isnt flat( I really want to contact with you, my e-mail is georgegeorgezz16@gmail.com ) Link to comment Share on other sites More sharing options...
r1dermon Posted July 15, 2011 Share Posted July 15, 2011 case bonded? like a solid propellent slug? in a core burner, the core will gradually grow larger as it burns, the result of this is a progressively larger surface area...the thrust curve in a design such as this is a progressive one, that is, it starts off slowly, and gradually builds thrust as it burns. this is not as efficient as a bates grain design, because it is more difficult to design specific motor parameters to adhere to the thrust profile...this is because the thrust profile is extremely dynamic, starting very low, and ending very high...parameters which are static, such as nozzle design, will only be optimal at one point on the thrust chart, where if you can obtain a very flat curve, those parameters can be tailored to that curve specifically for the time of the burn. Link to comment Share on other sites More sharing options...
THEONE Posted July 15, 2011 Author Share Posted July 15, 2011 (edited) Why i have this error on the BurnSim ? case bonded? like a solid propellent slug? in a core burner, the core will gradually grow larger as it burns, the result of this is a progressively larger surface area...the thrust curve in a design such as this is a progressive one, that is, it starts off slowly, and gradually builds thrust as it burns. this is not as efficient as a bates grain design, because it is more difficult to design specific motor parameters to adhere to the thrust profile...this is because the thrust profile is extremely dynamic, starting very low, and ending very high...parameters which are static, such as nozzle design, will only be optimal at one point on the thrust chart, where if you can obtain a very flat curve, those parameters can be tailored to that curve specifically for the time of the burn. But the bates grains also when they burns, more surface area burned each timeAlso as you can see a case bonded rocket is good enough see for example the ddd.bmp Edited July 15, 2011 by THEONE Link to comment Share on other sites More sharing options...
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