AP is a slow burning fuel compared to BP. So if you make an endburner, even at high pressure it will have a very low thrust due to the surface area. With AP, you really need to use some kind of core. Also, find the burning surface area of the AP. This, divided by the area of the nozzle hole should equal roughly 160-200, also called KN value. It looks in the video like yours was far less, like 75-125, and very low pressure, as it barely remained lit.
Thank you for the advice; I thought the rocket would explode if I had a core, but I guess that is not the case. I'll have to find some time to make the calculations and do it the right way. Hopefully I'll have a video of it :P
It looks like you are using a filled epoxy (ie filled with aluminium) commonly used for high-temperature pattern making. By all means, use this for the nozzle but not for the fuel. The aluminium would slow it down a lot!
5 stars though this is an awesome video..i like to see something different unlike the very common rocket candy videos..especially seeing an amateur rocket using APCP
ok heres some info that i think might help you...to start, the perfect ratio for you to try with your APCP rockets is a nozzle opening width of 1/8 inch to a 3 inch long by 3/4 cm wide circular core. This must be ignited from the top. Also for your nozzle, because of the way APCP burns, you have to have a convergent-divergent nozzle to get any good results. It looks like your mixture is perfect judging by the burn time of your APCP though...very good work..if you have questions message me
No, it was an end burner, since I figured that the propellant I was using should burn fast enough to support flight (but maybe not). I'm afraid that it would explode if it was core-burning. Thank you for the advice.
AP is a slow burning fuel compared to BP. So if you make an endburner, even at high pressure it will have a very low thrust due to the surface area. With AP, you really need to use some kind of core. Also, find the burning surface area of the AP. This, divided by the area of the nozzle hole should equal roughly 160-200, also called KN value. It looks in the video like yours was far less, like 75-125, and very low pressure, as it barely remained lit.
jr9950 4 years ago
Thank you for the advice; I thought the rocket would explode if I had a core, but I guess that is not the case. I'll have to find some time to make the calculations and do it the right way. Hopefully I'll have a video of it :P
slither888 4 years ago
What kind of binder is it and where do you get it? I cant find it anymore.
deepwater1974 4 years ago
It was epoxy binder, I don't have the brand off hand, but I bought it at wal-mart.
slither888 4 years ago
What department was it sold in so I know where to go when I get there? Thanks.
deepwater1974 4 years ago
hardware, where else?
slither888 4 years ago
It looks like you are using a filled epoxy (ie filled with aluminium) commonly used for high-temperature pattern making. By all means, use this for the nozzle but not for the fuel. The aluminium would slow it down a lot!
donuttyUK 4 years ago
The epoxy wasn't filled, but I did mix the fuel which included aluminum with the epoxy before I let it harden. Thanks for the advice though.
slither888 4 years ago
5 stars though this is an awesome video..i like to see something different unlike the very common rocket candy videos..especially seeing an amateur rocket using APCP
rebelcountry33 4 years ago
ok heres some info that i think might help you...to start, the perfect ratio for you to try with your APCP rockets is a nozzle opening width of 1/8 inch to a 3 inch long by 3/4 cm wide circular core. This must be ignited from the top. Also for your nozzle, because of the way APCP burns, you have to have a convergent-divergent nozzle to get any good results. It looks like your mixture is perfect judging by the burn time of your APCP though...very good work..if you have questions message me
rebelcountry33 4 years ago
if that was a core bruner it must be lit from the vary top not the bottom also close the noszel by .01%at a time and it will stop chuffing good luck
heliraptorcbm 4 years ago
No, it was an end burner, since I figured that the propellant I was using should burn fast enough to support flight (but maybe not). I'm afraid that it would explode if it was core-burning. Thank you for the advice.
slither888 4 years ago
That was pretty good, well done :P
trx636 4 years ago
Cool video. The last rocket do a similar coughing like some of my chlorate rockets. Why??
Snezzen 4 years ago
I really don't know why it did that. Perhaps the propellant grain was burning unevenly.
slither888 4 years ago
Not to bad, good bp rockets
Nighthawkinlight 4 years ago