U.S. Rockets BMR2 - Sonic Series Kits
 

I became interested in the two stage 29mm Sonic 160 rocket in a post that Jerry made in a thread discussing the new Estes F15 motors.

http://www.oldrocketforum.com/showt...47&page=1&pp=10

I had gathered together some parts thinking of scratch building a two stage minimum or near minimum diameter rocket to utilize a F15-0/F15-8 combinations of motors but after a little research I decided that the Sonic 160 would make for an interesting build. I found a blurb on the USR website on the Sonic Series page with a picture of a Sonic 160 model that peaked my attention:

"This Sonic 160 was flown at NARWIN-1, hosted by G. Harry Stine in Arizona in 1980. It took first place in NAR F Altitude with an FSI E60-0 to an FSI-F100-10, which combined were under 80 Newton-seconds total impulse, an F. It flew to 1041 Meters or 3414 feet to set the new record for that power class."

I contacted Jerry via email and found the Sonic 160 was out of stock at that time with USR and his dealers. I made the purchase and waited for a new batch of kits to be produced. I really wanted this kit in particular and when Jerry shipped the Sonic 160 kit to me he also informed me he was sending along a Microc and a Sonic Sounder payload rocket at no charge for those two kits. Basically I got the three kit series for the price of the Sonic 160

http://www.v-serv.com/usr/bmr2.htm

:)

So far, I have completed the Microc sans paint and unpacked the Sonic Sounder. Not intending to do full build threads I did take a few pics to post of the components and such and I produced OpenRocket files for these two kits first. I'm back in town now and will skip over the Sonic Sounder build for now to start on the Sonic 160 in hopes of getting it read to fly two stage at our high power field in Winnsboro this fall.

I'll post a few more tidbits and images as I progress through the builds so hopefully this will be a placeholder of sorts to motivate me as I only have weekend time lately to pursue my quest for staging those new Estes engines!

:D

The Microc
 

The Sonic Series Microc. I followed the kit instructions and used wood glue to build the model. I used Gorilla brand wood glue which I have become especially fond of. It sets fast and is strong for the plywood to paper bonds. I deviated from the instructions and used label paper to cover the fins instead of filling the grain and then sealed the edges with CA.

The tubes are thick walled and the nose cone appears to be polystyrene. Along with 1/16" three ply plywood fins it's a strong little rocket.

A few pics ...

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The Microc OpenRocket File & Screenshots
 

One thing I like about the latest OpenRocket download v13.09 is the Estes E16 and F15 motors are in the database, along with some recent CTI offerings.

Here's a few screen shots and the file for the Microc.

Wife is calling me away from the computer so this is all ... for now

;)

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The Microc Painted
 

First decent weather day here in South Louisiana so took the Microc outside to be painted. I still need to paint one fin black but will leave the Microc in the garage to dry some so the paint doesn't lift when I pull the masking off. There are some USR and kit name decals still to be applied.

I left the motor adapter out for now.

:)

Updated photo of the finished model.

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The Sonic Sounder
 

Second kit in the Sonic series I received was the Sonic Sounder. Much like the Microc, it is a 3FNC model with the addition of a payload section and a sleeker profile. An OpenRocket file with a few screen shots with a few common Estes engines.

It's stable with everything from an A8-3 through a D12-7 without any added nose weight, at least according to OpenRocket calculations. Flying with an altimeter in the payload section would move the CG forward some for an E9-8 engine. Since the final finished weight of the model has not yet been obtained this is the best estimation based on the kit parts that I have.

Airframe tubing and the nose cone for the Sonic Sounder are the same as used on the Microc. Builkhead plate is a plywood disc.

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The Sonic Sounder quick change motor mount. Two of the centering rings have a small piece of airframe that is bonded directly to the rings. This serves as a thrust ring so the mount can not move forward. The other two centering rings that are mounted forward slip fit into the airframe tube. The fins are mounted forward instead of flush with the rear of the airframe so a wrap of tape can go around the rear of the airframe and over the small piece of airframe on the quick change motor mount. This prevents the motor mount from ejecting rearward. A few wraps of tape around the motor and a wrap to secure the motor to the mount keeps the motor from ejecting rearward from the mount.

Because our fall flying season is fast approaching I am putting the Sonic Sounder build on hold to get the two stage Sonic 160 ready to fly.

:)

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Now let's see the performances with the specified (maximal) AT and CTI motors.

I couldn't find the E10 in the OpenRocket motor database but I did find the others you suggested to use in 24mm.

I was surprised that all except for the E30 didn't require any nose weight to be stable. The E30 required about 1/2oz. It is a high performance design.

You had tracked flights with similar staged models using the E6. Does a little over 4.000' sound about right for a single stage flight as indicated in OpenRocket?

I'm moving forward with the two stage Sonic 160 this weekend.

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Woof. That rocket looks like an Alpha on steriods. Very cool.

I'm going to have to take a closer look at the U.S. models. They just haven't been on my radar—you've inspired me.

http://v-serv.com/usr/kits/sonicsounder.htm

A: 376', 4s
B: 864', 6s
C: 1644', 7s
D: 2531', 9s
E: 4049', 9s
F: 6643', 10s
G: 7933', 11s

Those are for full power letter class motors with a medium thrust (F20, G30), except the G is a 62g one with ISP 200.

OpenRocket does not have a field for Total Impulse and the motor names do not have an ILP format (45F15J). If you run the rocket on older AT SU 24mm Full F such as the F44 or G such as the G70 (whatever it was), the performance will be "fairly good". :D

Jerry

PS. With AT re-releasing the I65, I suggest the USR Interroc (#1012) rocket.
http://v-serv.com/usr/kits/interroc.htm
Or the Sonic 3100-54mm (#1072)
http://v-serv.com/usr/kits/sonic3100.htm
CTI has a 24mm 6G case. :)
http://www.canadianrocketry.org/motor_index.php
144-G65-8A, 131-G84-10A, 143-G150-13A