AeroTech Information Release 10/18/07

AeroTech Information Release

10/18/07

AeroTech Showcases New, Improved G80T Motor at iHobby Expo in Chicago

AeroTech has engineered a new, greatly improved G80T Blue Thunder™ single-use model rocket motor, which is being shown for the first time to attendees of the iHobby Expo trade show in Chicago, IL from October 18-21.
The motor, which has been under development since July of 2006, features an all-new molded phenolic casing with a built-in thrust ring, and ships with a FirstFire Jr.™ 2-lead igniter. More importantly, it generates a total impulse over 40% greater than that produced by the current-generation G80T, along with a gorgeous translucent blue exhaust plume studded with prominent "mach diamonds".

"We used every trick in the book on this motor, and then invented some new ones" stated AeroTech/RCS president Gary Rosenfield. "As AeroTech's flagship single-use model rocket motor, we wanted the new G80T to embody the various casing and propellant technologies that we've been developing over the past few years, and to meet or exceed the performance and features of competitive offerings in as many areas as possible."

Ever since the November 2004 release of the first redesigned G80T in the current-generation molded casing, some AeroTech customers have expressed disappointment in the loss of total impulse from the previously certified 116 newton-seconds using a built-up paper-phenolic case design, to under 100 newton-seconds in the molded version. The loss was a consequence of translating the earlier motor design to the molded casing, which required a heavier case wall and substantial insulation thickness to protect it from excessive heating caused by the original G80T's "C-slot" propellant grain geometry.
The new G80T uses a dual "BATES" center core-burning grain configuration. This eliminates the need for extra case insulation and allows the largest diameter grain possible with a full 62.5 grams of propellant, the maximum permitted for a "legal" model rocket motor. The propellant composition was optimized to increase density and specific impulse (Isp) as much as practical within the parameters of AeroTech's DOT shipping classification and the inherent limitations of small rocket motor design. The nozzle exit cone was molded with a higher expansion ratio to increase motor efficiency. Other, proprietary design techniques were used as well.

Combined, these improvements have resulted in a delivered total impulse in excess of 130 newton-seconds, the highest ever achieved for a production single-use model rocket motor. The actual total impulse will be revealed once National Association of Rocketry (NAR) certification is granted for the new design. All this was accomplished without the use of exotic propellant chemicals or excessively high chamber pressures that could compromise motor reliability and safety.

The new G80T will be available in time delays of 7, 10 and 13 seconds. The 4-second delay has been discontinued, and customers are advised to use the next longer delay time increment for their rockets, due to the greatly increased total impulse. Other specifications of the new G80T include a burn time of 1.7 seconds, loaded weight of 128 grams, fired weight of 59 grams, diameter of 1.125" and a casing length of 4.88". The molded aft thrust ring has dimensions of 1.25" diameter X .25" long. Though the new G80Ts have a different exterior appearance due to the molded aft thrust ring, they will be clearly marked to differentiate them from the older G80Ts.

No user certification is necessary to purchase the G80T, though customers must be at least 18 years of age. AeroTech is now accepting orders for the new G80T motor and anticipates NAR certification to be received in late October to early November. Deliveries to dealers and distributors are expected to begin in late November.

A representative thrust curve of the new G80T, the NAR certification document, and motor instructions will be posted to the AeroTech Resource Library at https://www.aerotech-rocketry.com as soon as they become available.


AeroTech Consumer Aerospace is a division of RCS Rocket Motor Components, Inc., Cedar City, UT.

WooHOOO!!! :surprised::surprised::surprised:

One word describes this:

AWESOME!!!

I might just have to try one of these.

I. Need. Many. Of. These.

"...A delivered total impulse in excess of 130 newton seconds..."

That is impressive in a single-use, 62.5 grams of propellant motor.

It will allow safer flying of large, max. weight (3.3 pound) model rockets.

freaking whoop hoppity spangled pancake mix! awesome!!!!!!!!!!

Well Done!

BRAVO!!!

Can I trade in my old crappy G-80s.

This is exactly the motor I need for my minimum diameter rocket! I can't wait till it's available.

This is great news but also not-so-great news at the same time. There are cases where I actually need the 4 second delay on the G80 (Cosmodrome Aerobee-Hi booster) Guess I'll have to find a different booster motor now.

-Aaron

Way to go, Wiley!
Will there be any way to customize the delays?

heada said:

This is great news but also not-so-great news at the same time. There are cases where I actually need the 4 second delay on the G80 (Cosmodrome Aerobee-Hi booster) Guess I'll have to find a different booster motor now.

Click to expand...

I have the opposite problem - my LOC Aura needed a G80T-13 which is now going to be available again. My gain is your loss - sorry about that.

With LMS and RMS motors you can customize the delay in two ways - by drilling or by replacing the HDK or RDK element with another recommended one.

Is there any technical reason that you could not open the top of the motor dump the powder out and use a small drill bit and a depth gauge to remove delay from a single use motor?

Obviously Aerotech would have to sanction this before it would be OK'd but it seems technically possible.

uncle_vanya said:

With LMS and RMS motors you can customize the delay in two ways - by drilling or by replacing the HDK or RDK element with another recommended one.

Is there any technical reason that you could not open the top of the motor dump the powder out and use a small drill bit and a depth gauge to remove delay from a single use motor?

Obviously Aerotech would have to sanction this before it would be OK'd but it seems technically possible.

Click to expand...

That's what I was wondering, but I suspect the touch hole is quite small, and top drilling would be difficult.

uncle_vanya said:

With LMS and RMS motors you can customize the delay in two ways - by drilling or by replacing the HDK or RDK element with another recommended one.

Is there any technical reason that you could not open the top of the motor dump the powder out and use a small drill bit and a depth gauge to remove delay from a single use motor?

Obviously Aerotech would have to sanction this before it would be OK'd but it seems technically possible.

Click to expand...

Aerotech's instructions have you install the drilled part of the delay element so it is facing the propellant. That would be difficult to accomplish with a single-use motor. But, I've (accidently) assembled my reloads with the drilled part facing the top of the motor and it didn't seem to cause any problems.

My guess is that you'd have to drill slightly farther for the same delay (since there would be less surface area burning), but it wouldn't be much different.

-- Roger

This sounded fantastic until I got to the part where they dropped the -4. That's the only delay I can fly my Apogee Saturn V with, and I stopped flying it when the old AT G80-4's started popping ridiculously early (some less than 1 second after burnout, most in the 2 second range). If form hold, maybe I should go with the -7's, figuring their real delay would be closer to 3-4 anyway.

The next problem becomes how to make sure when ordering online we're getting old versus new. This is yet another case where an "improved" motor continues to be sold under the original identification, making NAR certification and contest use problematic--same identification, yet two completely different motors...

--Chan Stevens

This is great news and I like that there will be a longer delay option. As long as they don't cost an arm and both legs I'll hobble to my friendly neighborhood motor vendor and try some. 130 N-s (drool).

chanstevens said:

This sounded fantastic until I got to the part where they dropped the -4. That's the only delay I can fly my Apogee Saturn V with, and I stopped flying it when the old AT G80-4's started popping ridiculously early (some less than 1 second after burnout, most in the 2 second range). If form hold, maybe I should go with the -7's, figuring their real delay would be closer to 3-4 anyway.

The next problem becomes how to make sure when ordering online we're getting old versus new. This is yet another case where an "improved" motor continues to be sold under the original identification, making NAR certification and contest use problematic--same identification, yet two completely different motors...

--Chan Stevens

Click to expand...

Yeah, but this 3G version will have almost 1/3 more thrust than the current 2G. Plus, I need the longer delay for my throw-away rockets

How much?

The guys at AeroTech have done it again. I have one of their Cheetah's, and after flying it on many motors, I was weary of trying a 10 second delay as even the G64-10W was a little short. The 13 second delay may just be the hot ticket. I would think this new G80 would go very high in that rocket.

Gary, if you see this and can share the thrust curve, I could make a .eng for that motor. I have TCT and can trace it, and tweak the trace to the specs. I would like to see what this motor would do in my Cheetah. I've flown some really high flights with that rocket. Chester is a fast little devil too. After mnay flights Chester looks as brand new as he was when his build was completed. Looks like we might have to send Chester up on a speed run again. Hang in there Chester...keep your fins on.

wingarcher said:

How much?

Click to expand...

Probably more than I'll pay for most flights, but I'll still grab a few. I still remember $10 G80FWLs (including shipping and HAZMAT) from the original Magnum. (AT was the source, naturally)

Hmm, wondering if I missed it or not, but will this new and very improved G80 be available in RMS or LMS?

I think that they dropped the -4 because even though it operates at "normal" motor pressures, it may be operating at the higher end of "normal" pressures, which would me a greater chance of a blowby because you will need more delay material between the propellant and ejection charge at higher pressures . Think what would happen if you get a -4 that was really a -2, would that be enough webbing?

Just my theory .

Oh, any idea how much this will be? They improved the motor, I wonder if they improved the price? Or at the very least, kept it the same?

Now, if they could somehow improve the G40. I loved the original WL 120 n/s G40's. The "new" G40's are not the same animal I used to buy the classic G40's all the time

heada said:

This is great news but also not-so-great news at the same time. There are cases where I actually need the 4 second delay on the G80 (Cosmodrome Aerobee-Hi booster) Guess I'll have to find a different booster motor now.

-Aaron

Click to expand...

Looks like I have to dust of the Aerobee Hi and see what the -7 second delay does in the booster. I'll post a note on the website to warn people that the new G80 may have a big impact in the booster. Now that I'm up north again it might be Spring before I get to lauch this one again. One more item on my to do list.

mike
cosmodrome rocketry

Cosmodrome said:

Looks like I have to dust of the Aerobee Hi and see what the -7 second delay does in the booster. I'll post a note on the website to warn people that the new G80 may have a big impact in the booster. Now that I'm up north again it might be Spring before I get to lauch this one again. One more item on my to do list.

mike
cosmodrome rocketry

Click to expand...

I'll volunteer to test it out with mine if you can get me one of the new motors.

The old G80 (full G80, certified in '95) had a total impulse of 116Ns and a burn time of 1.5s(giving an average thrust of 77.3N) as seen on the cert file on AT's website. This new G80 has "total impulse in excess of 130"Ns and a burn time of 1.7s so if we assume 130Ns and 1.7s burn time we get an average thrust of 76.5N or almost exactly what the old G80 was (as AT said more than 130, we know it will be slightly higher than these numbers) The old G80 with a 7 second delay was too long, we know this from failed or nearly failed flights. If this new version of the G80 has almost the same profile as the old motor (just a slightly longer burn with slightly more impulse) than I would think it's going to fly like the old motor. One thing that we would have going for us is the 0.2 seconds of additional burn time translating into additional altitude. I don't think the additional altitude gained by 0.2 seconds of burn will be made up by the additional 3 seconds of delay.

If the new G80 is offered in a RMS or LMS version, would AT bless drilling the delay to less than 7 seconds? If so, then this is all moot and I'll be happy once again.

-Aaron

heada said:

I'll volunteer to test it out with mine if you can get me one of the new motors.

The old G80 (full G80, certified in '95) had a total impulse of 116Ns and a burn time of 1.5s(giving an average thrust of 77.3N) as seen on the cert file on AT's website. This new G80 has "total impulse in excess of 130"Ns and a burn time of 1.7s so if we assume 130Ns and 1.7s burn time we get an average thrust of 76.5N or almost exactly what the old G80 was (as AT said more than 130, we know it will be slightly higher than these numbers) The old G80 with a 7 second delay was too long, we know this from failed or nearly failed flights. If this new version of the G80 has almost the same profile as the old motor (just a slightly longer burn with slightly more impulse) than I would think it's going to fly like the old motor. One thing that we would have going for us is the 0.2 seconds of additional burn time translating into additional altitude. I don't think the additional altitude gained by 0.2 seconds of burn will be made up by the additional 3 seconds of delay.

If the new G80 is offered in a RMS or LMS version, would AT bless drilling the delay to less than 7 seconds? If so, then this is all moot and I'll be happy once again.

-Aaron

Click to expand...

I agree, I don't think it'll work. I'm going to have to spend some time researching the alternatives.

mike
cosmodrome rocketry

heada said:

If the new G80 is offered in a RMS or LMS version, would AT bless drilling the delay to less than 7 seconds? If so, then this is all moot and I'll be happy once again.

-Aaron

Click to expand...

What do people that have flow the Aerobee Hi think about the G77R-4 or the G79W-4 as booster motors? I've never used either.

thanks
mike
cosmodrome rocketry

Cosmodrome said:

What do people that have flow the Aerobee Hi think about the G77R-4 or the G79W-4 as booster motors? I've never used either.

thanks
mike
cosmodrome rocketry

Click to expand...

It just so happens I have use both the G77R and G79W (both single use) and have a few still. I can try them out and see what I get. The next chance for me would be either this weekend or mid November (I have a large project planned for this weekend so I don't think I'll be able to test this weekend).

Looking at the G77 cert doc, it has a lower total impulse (102.9Ns) but burns for 1.3 seconds giving an average of 79.2N which is good but the thrust curve shows that it has an initial thrust of about 70N building up to 100N at about the 0.5 second mark. Compare this to the G80 which has an initial thrust of about 100N (big spike in the first part of the burn helps get the rocket off the pad faster, good for a booster) The G77-4 might work but it'll be slower off the pad than the G80 was.

The G79 has 108.3Ns of total impulse and a 1.5 second burn time giving 72.2N average thrust (lower than both the G80 and the G77) It also has a lower initial thrust of about 40N and builds over time to about 80N at 0.5 seconds. The lower initial thrust and lower peak thrust somewhat rules the G79 out as a replacement for the G80 booster.

-Aaron

heada said:

It just so happens I have use both the G77R and G79W (both single use) and have a few still. I can try them out and see what I get. The next chance for me would be either this weekend or mid November (I have a large project planned for this weekend so I don't think I'll be able to test this weekend).

Looking at the G77 cert doc, it has a lower total impulse (102.9Ns) but burns for 1.3 seconds giving an average of 79.2N which is good but the thrust curve shows that it has an initial thrust of about 70N building up to 100N at about the 0.5 second mark. Compare this to the G80 which has an initial thrust of about 100N (big spike in the first part of the burn helps get the rocket off the pad faster, good for a booster) The G77-4 might work but it'll be slower off the pad than the G80 was.

The G79 has 108.3Ns of total impulse and a 1.5 second burn time giving 72.2N average thrust (lower than both the G80 and the G77) It also has a lower initial thrust of about 40N and builds over time to about 80N at 0.5 seconds. The lower initial thrust and lower peak thrust somewhat rules the G79 out as a replacement for the G80 booster.

-Aaron

Click to expand...

What about the G71R-4? If I recommend a 1/2" spacer between the thrust ring and the MMT the motor would only take up more room in the booster due to the ejection charge. I'll still have to pach a chute to make sure there's still enough room. With the 1/2" spacer the nozzle would be in the same possition so the stability shouldn't be a factor.

mike
cosmodrome rocketry

Cosmodrome said:

What about the G71R-4? If I recommend a 1/2" spacer between the thrust ring and the MMT the motor would only take up more room in the booster due to the ejection charge. I'll still have to pach a chute to make sure there's still enough room. With the 1/2" spacer the nozzle would be in the same possition so the stability shouldn't be a factor.

mike
cosmodrome rocketry

Click to expand...

I think the G71-4 is your winner. It has an the initial spike to about 120N that tapers off over 1.5 seconds so it has the punch to get it off the pad quick but still a long enough burn to get it a few hundred feet up before staging happens. It has a slightly lower average thrust and total impulse but it has the 4 second delay as well as being cheaper than a SU motor.

I would check the CP/CG with and without the spacer. I honestly don't think 1/2 inch will make that much of a difference to effect the stability.

And now back to your regularly scheduled posts (sorry for the OT talk)

-Aaron

EDIT: You actually don't want the spacer as that will move the motor forward by 1/2 inch and thus moving the CG ever so slightly forward too. The 29/40-120 is slightly shorter than the G80 SU motor and so it should end up as a wash when it comes to space inside the MMT.

I'd like to see the 2 thrust curves overlapped on the same graph.