Aerotech F44 "Econo-Max" 24mm x 70mm ???

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Would anyone mind if we got this thread back on track?

Aerotech posted a photo on their Facebook.
1655640_10152177933993955_780905847_o.jpg


Alex
 
I notice in response to a question that AT says "the F44W contains less than 30 grams of propellant, the G74W contains more than 30 grams." So one should expect hazmat shipping for the G74. I'll be interested to see what the total impulse of this guy is, I'm guessing it won't be much above 90 N-s.
 
I am hoping that is approaches the G80 total impulse. If they can cram over 40 N-s into the 24mm casing and they already got 137 N-s into the 29mm casing with the BATES grain G80 (T proellant), then they probably have performed a similar engineering marvel using the W propellant.

As for the shipping on the G74, we'll just have to buy a large number of them so that the box is nice and full and spreads out the shipping over a large number of motors.

Set aside those tax refunds (and/or, if you work for Boeing, your EIP).

mikec said:
I notice in response to a question that AT says "the F44W contains less than 30 grams of propellant, the G74W contains more than 30 grams." So one should expect hazmat shipping for the G74. I'll be interested to see what the total impulse of this guy is, I'm guessing it won't be much above 90 N-s.
Click to expand...
 
mikec said:
This motor is considerably shorter than the G80 (83mm versus 128mm) so this doesn't seem likely to me.
Click to expand...
Ya, and with the amount of "effects stuff" included in WL vs. NT (in the new G80), squeezing 137+ Ns out of it will be a challenge. The C* hit is pretty significant for that. Unless, of course, "inventing some new ones" means modifying WL within its DOT spec to improve its performance. As long as they still have the trademark smoke, flame, and roar, I'm on board for anything!
 
Good point.

And it is an "Economax", so being "Econo" would make it lower total -impulse as well as lower price, BUT since it is a "max" and not a "jet" I am expecting more total impulse than in an "Econojet".

The "max" part is the engineering wizardry. This should be pretty cool.

mikec said:
This motor is considerably shorter than the G80 (83mm versus 128mm) so this doesn't seem likely to me.
Click to expand...
 
These look like a good SU product with a great price. I'm sure I'll get a bunch when available.

I already like the E30s and F32s.
 
I think the max part is stressing max economy not max performance. Then again 44 newtons average thrust is pretty impressive for a 24x70 white propellant. I can't believe the price of these economax motors, they're almost as cheap as reloads.
 
Well, since the price is comparable to the Econojets, there does not seem to be any additional "Econo" being "maxed out". Additionally, Aerotech has pretty much hinted fairly directly that they used design techniques from the G80 on these new motors (plus other new magic), so it would be reasonable to conclude or infer that since the "Econo" portion is unchanged the "max" portion would most likely refer to the performance.

And, YES indeed, 44 Newtons of average thrust in the 24mm diameter E is pretty amazing compared to the E20/E15 (identical motors) which actually have 22 Newtons average thrust.

https://www.nar.org/SandT/pdf/Aerotech/E20.pdf


JPVegh said:
I think the max part is stressing max economy not max performance. Then again 44 newtons average thrust is pretty impressive for a 24x70 white propellant. I can't believe the price of these economax motors, they're almost as cheap as reloads.
Click to expand...
 
shreadvector said:
Additionally, Aerotech has pretty much hinted fairly directly that they used design techniques from the G80 on these new motors (plus other new magic)
Click to expand...

I'm willing to bet that these new motors have Bates Grains and not C-slot grains, as to similarity to the new G80's. This will also explain the higher middle number in these motors' designations.
I am glad Aerotech keeps releasing new stuff all the time... It's great for the hobby.
 
DanFrank said:
I'm willing to bet that these new motors have Bates Grains and not C-slot grains, as to similarity to the new G80's. This will also explain the higher middle number in these motors' designations.
I am glad Aerotech keeps releasing new stuff all the time... It's great for the hobby.
Click to expand...

Why is the single-use G78G not higher impulse, then? That motor's thrust curve seems to indicate a BATES grain, as do the diagrams in the instructions, and Mojave Green is high-density and fairly high specific impulse. Even so, it only has 110 Ns versus the 130 of the G80T. (Speaking of which, the first thrust curve of the G78G on thrustcurve.org is actually that of the G80T)


Aside from that, it reminds me that Aerotech posted a picture of a highly progressive thrust curve a while back. I wonder if one of these corresponds to that thrust curve: a single grain a good deal longer than a standard BATES motor. It would be like a baby G138! Fun in a minimum diameter...
 
One of my Estes Crossfire Nose Cones is going to ride one of these Motors. I'de like to say the Whole Rocket, but the only Part I'll use from the Kit is the Nose Cone.

Actually, scratch that Idea. I put too much work into my still not finished 24mm Crossfire to lose it on a crazy overpowered Motor like this.
 
Last edited:
I think we just need to try them out.......... Fred, work your magic. :)
 
CarVac said:
Why is the single-use G78G not higher impulse, then? That motor's thrust curve seems to indicate a BATES grain, as do the diagrams in the instructions, and Mojave Green is high-density and fairly high specific impulse. Even so, it only has 110 Ns versus the 130 of the G80T. (Speaking of which, the first thrust curve of the G78G on thrustcurve.org is actually that of the G80T)


Aside from that, it reminds me that Aerotech posted a picture of a highly progressive thrust curve a while back. I wonder if one of these corresponds to that thrust curve: a single grain a good deal longer than a standard BATES motor. It would be like a baby G138! Fun in a minimum diameter...
Click to expand...
Different propellants have different Isps. The nominal Isp for APCP is ~ 2 Ns/gram, so 30 gram mailable motor are ~ 60 Ns or ~50% F. Blue Thunder is a bit more, White Lightning is a bit less. A 30 gram mailable Blue Thunder motor should be a 50%+ F while a 30 gram mailable White Lightning motor should be a 50%- F.

Bob
 
bobkrech said:
Different propellants have different Isps. The nominal Isp for APCP is ~ 2 Ns/gram, so 30 gram mailable motor are ~ 60 Ns or ~50% F. Blue Thunder is a bit more, White Lightning is a bit less. A 30 gram mailable Blue Thunder motor should be a 50%+ F while a 30 gram mailable White Lightning motor should be a 50%- F.

Bob
Click to expand...

The single-use G78 is not mailable, though.
 
Here's the latest info on Aerotech website.


NAR certified motor specifications:

F44W-4, 8
Dimensions: 24mm x 70mm (same physical size as an Estes® D12)
Total Impulse: 41.46 Newton-Seconds
Peak Thrust: 49.54 Newtons
Average Thrust: 40.36 Newtons
Propellant mass: 19.7 grams
Loaded mass: 48 grams (vs. 83 grams for an Estes® E16)
USPS mailable
Retail Price: $23.99 (pack of two)

G74W-4, 6, 9
Dimensions: 29mm x 83mm
Total Impulse: 82.74 Newton-seconds
Peak Thrust: 94.48 Newtons
Average Thrust: 79.64 Newtons
Propellant mass: 39.3 grams
Loaded Mass: 87 grams (vs. 104 grams for an Estes® F15)
Retail Price: $26.99 (pack of two)
 
CarVac said:
The single-use G78 is not mailable, though.
Click to expand...
There are NO mailable single use G-impulse motors. You would have to have a minimum specific impulse of 80Ns/30g=2.67 Ns/g or 272 s, and that's not happening with hobby APCP.

Bob
 
Really looking forward to those F44s especially.

Strange entries at Hobbylinc:

G74W 29/83 Econo-Max Motor (2) G Composite Model Rocket Engine
Product Number: ARO77406
Aerotech Product Number: 77406
$17.19

https://www.hobbylinc.com/aerotech_...motor_2_g_composite_model_rocket_engine_77406

G74W 29/83 Econo-Max Motors (2) G RMS Model Rocket Engine
Product Number: ARO77409
Aerotech Product Number: 77409
$18.59

https://www.hobbylinc.com/aerotech_g74w_29:83_econo-max_motors_2_g_rms_model_rocket_engine_77409

The 2/27/2014 Aerotech press release announcing the Economax motors:

AeroTech Announces Economax™ Line of Model Rocket Motors

“Composite Performance at Black Powder Prices” is the slogan for a very innovative new line of model rocket motors from AeroTech. The first two motors are designed to compete head-to-head with the black powder “E” and “F” motors recently released by Estes®. AeroTech’s new Economax™ composite motors have significantly more power than an Estes® black powder motor, burn much faster, and are up to 43% lighter. The result: it’s like putting a “Bolt of Lightning In Your Rocket!”

The motors are being offered in packs of two with some revolutionary price points. The retail price of a pack of two Economax™ F44W motors is $23.99 (the same price as a pack of two Estes® E16 motors) and the G74W two-pack retails for just $26.99 (the same price as a pack of two Estes® F15 motors ).

Vice President Bill Stine says “We have really made it easy for our retailers to sell these new Economax™ motors as a motor option for the entire Estes® PRO SERIES™ line of rockets. The packaging does a great job of clearly letting a consumer know what Estes® kits the motors can be flown in because it has an actual chart listing all the kits. Retailers asked us to make it easier for a consumer to understand what rockets our motors can be used in – and we’ve responded!”

So how did AeroTech squeeze nearly 83 N-sec out of case size that previously was limited to around 53 N-sec (a 56% increase)? According to AeroTech President Gary Rosenfield, after 41 years of designing composite rocket motors, a number of new design ideas all came together:

• “High-solids” propellant with higher specific impulse (Isp), high density and higher burn rate to minimize throat erosion and delay grain length.

• Volumetrically efficient “finocyl” propellant grain design.

• No separate case liner, so larger diameter propellant grain.

• Longer propellant grain due to shorter delay and bulkhead.

• Slightly higher motor peak operating pressure.

• Relatively flat thrust curve to increase average pressure.

Both the F44W and G74W use AeroTech’s very popular White Lightning™ propellant.
 
Nothing strange about the motors, or the notice. They were certified by S&T and I assume that AT is currently making enough of them to appease the masses. New motor casing size however. Looks like https://www.rocketmotorparts.com/2980_EMK__Single-Use_Experimental_Motor_Kit/p1577809_7833141.aspx

R143NAR S&T NEW MOTOR CERTIFICATIONFebruary 23, 2014
The following motors have been certified by NAR Standards & Testing for
general use as Model Rocket Motors effective February 19, 2014.


*************************************
Aerotech:
F44W-4,8
24mm x 70mm
41.46 Newton-seconds Total Impulse
49.54 Newtons Peak Thrust
40.36 Newtons Average Thrust

Propellant mass: 19.7 grams


G74W-4,6
29mm x 83mm
82.74 Newton-seconds Total Impulse
94.48 Newtons Peak Thrust
79.64 Newtons Average Thrust

Propellant mass: 39.3 grams

Bob
 
I think the unspoken question about strangeness or weirdness had to do with the oh-so-common Hobbylinc habit of listing single use motors in reloadable categories and reloadable motors in single use categories.

Ignore the categories or contact them to inform them of their categorization errors. Therer is a 23% chance they will correct it based upon past history.
 
shreadvector said:
I think the unspoken question about strangeness or weirdness had to do with the oh-so-common Hobbylinc habit of listing single use motors in reloadable categories and reloadable motors in single use categories.

Ignore the categories or contact them to inform them of their categorization errors. Therer is a 23% chance they will correct it based upon past history.
Click to expand...

Yes, that's it. And in this case they have two items listed for G74W 29/83 Econo-Max Motor --- one is described like you would expect and one is described as a reloadable for RMS. Two different item numbers, two different prices, both with Economax in the name, both in the reloadable category, one SU, and one RMS. Something is not quite right.
 
As I stated, there is nothing at all surprising about Hobbylinc listing items in the wrong category.


https://www.aerotech-rocketry.com/news.aspx?y=2014#n151

The G74 comes in -4, -6 and -9 delay times.

NAR announcement only listed two of those times. Data sheet is not linked online on NAR website.

I would 'guess' that the Hobbylinc listings are for the -6 and the -9 based upon the product number. They are all single use. There is no question about that.

ThirstyBarbarian said:
Yes, that's it. And in this case they have two items listed for G74W 29/83 Econo-Max Motor --- one is described like you would expect and one is described as a reloadable for RMS. Two different item numbers, two different prices, both with Economax in the name, both in the reloadable category, one SU, and one RMS. Something is not quite right.
Click to expand...
 
shreadvector said:
As I stated, there is nothing at all surprising about Hobbylinc listing items in the wrong category.


https://www.aerotech-rocketry.com/news.aspx?y=2014#n151

The G74 comes in -4, -6 and -9 delay times.

NAR announcement only listed two of those times. Data sheet is not linked online on NAR website.

I would 'guess' that the Hobbylinc listings are for the -6 and the -9 based upon the product number. They are all single use. There is no question about that.
Click to expand...

You're right about this not being surprising. Until I figured this out, there were very common items I thought Hobbylinc just didn't carry at all, because I expected them to be categorized correctly. Best bet is always to do a search if it doesn't show up in the category you expect. I have had some success with sending them an email about these kinds of issues and getting it corrected. (Maybe even better than 23% :wink:)
 
ThirstyBarbarian said:
You're right about this not being surprising. Until I figured this out, there were very common items I thought Hobbylinc just didn't carry at all, because I expected them to be categorized correctly. Best bet is always to do a search if it doesn't show up in the category you expect. I have had some success with sending them an email about these kinds of issues and getting it corrected. (Maybe even better than 23% :wink:)
Click to expand...



I used 23% but I forgot to mention that 47% of all statistics quoted on the web are made up.
 
bobkrech said:
Nothing strange about the motors, or the notice. They were certified by S&T and I assume that AT is currently making enough of them to appease the masses.
Click to expand...
Let me reformat and highlight to point out the weirdness:

G74W 29/83 Econo-Max Motor (2) G Composite Model Rocket Engine
G74W 29/83 Econo-Max Motors (2) G RMS Model Rocket Engine
Aerotech Product Number: 77406
Aerotech Product Number: 77409

https://www.hobbylinc.com/aerotech_g7...t_engine_77406
https://www.hobbylinc.com/aerotech_g7...t_engine_77409

An RMS version and a listed "Aerotech product number" for that motor that doesn't exist?
 
What a mess these new motors are causing on web sites for some reason. First, Hobbylinc lists the F44-4W as being in stock, then it completely disappears from their site, with only the F44-8W now being listed, still not in stock, and now listed as requiring hazmat fees even though each motor only contains 19.7g of propellant. Could this be because of the (insanely stupid) hazmat issues with the tiny amount of pyrogen in their included igniters, the reason Estes eliminated pyrogen from their new "starters"?

Also, check out Tower Hobby's page for the F44:

https://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LNEBCL

That's a very strange looking pair of "single use" motors.
 

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