Russian S-125 GOA
 

I've decided to go with a Russian GOA missile for NARAM 60 since I've got lots of scale data on it.
I am going to scale the model so the booster stage body tube is 3" in diameter. Eight years ago I started an stopped on a GOA that was sized around a 4" tube for the booster. It was going to be over weight so I stopped construction on it. That and the fact I couldn't cast a good part from my molds. I have most of the Cad work done already so I can start building in the near future.

John Boren

There is no such thing as "overweight" with readily available HPR SU and RMS motors ! :D
If it is too heavy for the original intended motor, just kick it in the pants HARDER !
Stick with 4" and use a H250G. ;)

Well, your wrong. I believe there is a weight limit for model rockets. Since this models sole reason for being was to fly at NARAM and most likely never fly again it had to be under the weight limit, plus I'm not sure if I could go up higher then a G motor in impulse. This would mean 8 years ago an F50 or so motor in the booster and another E or F in the sustainer.

I'm not one to over power any of my models. I really like to see them go up and come back down again.


John Boren

John,

What's your feeling on getting the parts 3D printed instead of casting from molds? Are you an old school craftsman or a pragmatist? And is this a two stage with composites, or black powder?

I've been 3D printing parts at Estes for 9 years. A 3D printed fin done on the machine at work wouldn't hold up long enough for me to use for a Scale Model I intend to enter at NARAM. I do a little of every type of modeling. Some of these parts I can craft by hand, some I can use a 3D printer for, then turn these into masters and then cast a part out of resin or if needed make a hollow fiberglass part. Below is a link to my first GOA where some of the parts were 3D printed, then cast and some were created out of wood, then cast.

So I personally am fine building a model any way I can. Oh and by the way I just purchased my own 3D printer for home use and I do intend to see how it prints some of these parts out.

It will be too heavy for BP motors so it will most likely use F composite motors in both stages.

http://johnboren.com/html/goa_missile.html



John Boren

Ahhh, gotcha.
I missed the fact that you were going to enter it in scale competition at NARAM.
I thought you were just flying it there.