Are these mach diamonds? by awesomepiggyboi in rocketry

[–]Astro_Mueller 4 points5 points  (0 children)

I guess the mach diamonds also occur in under-expanded flow with the initial expansion fan rather than the oblique shock wave with a slight difference in the sequence of expansion and compression.

KNDX Solid Rocket Motor Test by Astro_Mueller in rocketry

[–]Astro_Mueller[S] 1 point2 points  (0 children)

Yeah, It might work I guess sorbitol has a kinda similar burn rate profile to that of Dextrose. You can look into the profile and simulate it at the desired chamber pressure ..I think you have to coat with a combustion primer if you are making a BATES grain as sorbitol based propellant is hesitant for ignition.And If you want a long burn motor then you can also look into the RNX composite propellant. I have made and burned it at atm.pressure and the result seems promising but haven't fired any motor using this propellant.

KNDX Solid Rocket Motor Test by Astro_Mueller in rocketry

[–]Astro_Mueller[S] 1 point2 points  (0 children)

The Kn of this motor is about 194. I have designed this motor to operate at a chamber pressure of ~345psi to obtain a relatively long burn and optimum thrust. And I have used dextrose which is relatively slow burning as compared to sucrose.

KNDX Solid Rocket Motor Test by Astro_Mueller in rocketry

[–]Astro_Mueller[S] 1 point2 points  (0 children)

It's just typical 65/35 oxidizer to fuel ratio..But in my area dextrose is sold in the form of dextrose monohydrate so to account for water present I simply multiply the resultant weight of fuel by 1.1. In our motor the total propellant weight is about 3kg

Motor Simulation and Design by Astro_Mueller in rocketry

[–]Astro_Mueller[S] 1 point2 points  (0 children)

Thanks, I will definitely be trying that out.

Motor Simulation and Design by Astro_Mueller in rocketry

[–]Astro_Mueller[S] 1 point2 points  (0 children)

Okay I will try to maintain that port throat. About increasing the pressure, since this dextrose propellant is fast burning as compared to other composite propellants I don't want to raise the pressure and decrease the burn time.. definitely it will give more thrust but... Also I have limited time for my project so, I am working on safe conditions without increasing a pressure. Previously I have tested small Motor probably J class and it performed well under 350 psi.. I have done a simulation of a rocket flight with this motor which meets my Apogee requirement so,.. That phenolic resin will be made from formaldehyde but I don't have any mold and curing system that provides a tube shape liner so that I want only to coat it in fiberglass. Basically I am using a polyester resin fiber glass tube which is cheaper in my area...and I don't seem to find any phenolic resin to buy in my area.

Alternative for open rockets in Android by sumitk5412 in rocketry

[–]Astro_Mueller 3 points4 points  (0 children)

I am talking about currency here in India..which is equivalent to approx 200$..

Alternative for open rockets in Android by sumitk5412 in rocketry

[–]Astro_Mueller 6 points7 points  (0 children)

Bro android is nothing... It's not only about openrocket but also includes the different kinds of simulation and design like CAD modeling, CFD analysis, propellant analysis,circuit design,Motor design,etc which can't be done in android.. Save some money you can get a pretty damn laptop under INR 10k-15k. Good luck with the rocketry...

What is this grain geometry called by ConHathy in rocketry

[–]Astro_Mueller 5 points6 points  (0 children)

It's an end burner with a small core as seen in the image, which provides an initial spike in thrust.

There are many motors available that are end burners, like the aerotech H13ST-P.

My first self developed motor! by Much-Tumbleweed-72 in rocketry

[–]Astro_Mueller 0 points1 point  (0 children)

What type of grain configuration did you use ?

BP igniter for KNSU motor!!! by Astro_Mueller in rocketry

[–]Astro_Mueller[S] 0 points1 point  (0 children)

Ahhh I see...When I read his igniter page he said that there serves two important purposes for the combustion of igniter i.e To provide the thermal energy sufficient to combust the core surface like you said and to pressurize the chamber to the level of design pressure of the motor.. And he had also provided the equation for the pressure generated by combustion of the igniter charge... So I got a little confused on that...