Aerotech - G79 RMS Motor {Motor}

Aerotech G79 RMS Motor

Aerotech - G79 RMS Motor {Motor}

Contributed by Dick Stafford

Construction Rating:
Flight Rating:
Overall Rating:

Manufacturer:

Aerotech

Brief:
This is a comparison review of Aerotech’s new G79W, including the new 29/120 RMS case.

Construction:

Although this product was introduced at LDRS 23 in July 2004, my casing (S/N 037) has a manufacturing date of 1/8/02. This product was obviously in the works for a while. The case is new and is not interchangeable with the 29/40-120, but the closures are the same as those used with the 29mm high power cases.

The reload kit is a typical AT reload so I won't go into the details--liners, insulators, O-rings, two slugs, etc. Here is a comparison between the G79 and the G80:

	G79 ¹	G80 ²
Type	RMS	SU
Total Impulse (N-sec)	115	120
Burn Time (sec)	1.5	1.5
Propellant Weight (g)	58.6	57.4
Propellant Type	White Lightning	Blue Thunder
Delays (sec)	6, 10, 14	4, 7, 10
Igniter	First Fire	Copperhead
Loaded Weight (g)	158	120
Length (in)	5.9	4.88
Retail (as of 07/20/04)	$11.95	$18.95
Notes: ¹ per AT. ² per NAR.

The main trade-offs include:

You have to build the motor instead of just slapping the single use G80 in.
Loaded motor is slightly heavier and just a hair less oomph than the G80.
Longer than the G80, which is a problem if you used a (evil) motor block.
The longer delays may or may not be beneficial to you. I'd rather have a -4 than a -14. (I overbuild, what can I say?)
Much better igniter with the reload. I'll be dipping fewer igniters than before.
The reloads are much cheaper. I hear the G80s are headed up in price again.

Construction Rating: 5 out of 5

Flight:
I have flown this twice...and I like it. Lots of white smoke like my beloved G80FWLs. I do have two observations:

The delay components all fit together easily, whereas on the 38mm RMS it takes some effort (very little, but some) to get it together. A good example is the delay spacer--this one fell right in. On the 38mm RMS I have to work them in.
The threads of the forward closure were the dirtiest I've ever seen in an RMS (post flight, of course). Also, there was lots of gunk between the liner and the case on the forward end. The aft end was not unusually dirty.

I will monitor The Rocketry Forum to see what other people’s experiences are.

Flight Rating: 4 out of 5

Summary:
I am ecstatic about this product release. I love G80s and the G79 is a lot cheaper. (Not as cheap as $10 G80-FWLs from Magnum, but those days are gone for good.) In more good news, AT has promised Redline loads soon. (I though I saw Blue Thunder reloads too, but cannot find the reference.)

Overall Rating: 5 out of 5

Comments:

B.S. (July 29, 2005)

I have flown the G79R 4 times and the results are great. Assembly went together without a hitch. Clean up was easy with minimal work. And the RED FLAME, all I can say is try it for yourself. A big thumbs up to Rocketmotion for showing me the ropes. This new 29/120 has only a few reloads for it now. I hope for are in the works, I give it 2 thumbs up.

D.S. (August 1, 2005)

I'd point out that the G79W is not a red motor, so the previous comment should be in relation to the G77R.

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