# New AT motors certified this month

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#### JohnCoker

##### Well-Known Member
Thanks to Alan Whitmore, we have data on the 5 new AeroTech motors certified on Dec. 7:

#### mikec

##### Well-Known Member
Thanks!

The M2050X is a reload according to the AT Facebook page (75/5120 case) but it's listed as SU.

#### watermelonman

##### Well-Known Member
Wow the O5280 is finally certified? I think it was going to be "next month" for about three years there.

#### Rocketjunkie

##### Addicted to APCP
Yes, K455 is same as the K375 reload. Compare on thrustcurve.org

#### Hooked On Rockets

##### Well-Known Member
Wow!! That O-motor is amazing!!!
Price....$1999.00 Even if I was qualified to buy it.....I'm trying to think of the last time I spent that much on an AUTOMOBLE!!! It's been 5 years....at least... I guess I'm just "thrifty" (financially inhibited) .....LOL This IS an amazing sport...!!!! So....is there a "GoFundMe" function on TRF????? LOL I only want THREE of those...$6000.00..
If everyone pitched in $3000.00 a piece....it would only take TWO PEOPLE!!!!! LOL Thanks All!!! I love rockets and TRF!!! Except for the "squirrel"......yeppers, I HAD to add that....... SS #### cerving ##### Owner, Eggtimer Rocketry TRF Sponsor TRF Supporter Hey, I know a guy who races cars, and he spent more than that in one weekend on tires... It would be cool to see the cert test firing video, that's about as close to one of these beasts as most of us will get. #### tfish ##### Well-Known Member Tony #### Rob702Martinez ##### Zip-Tie Oversight Committee TRF Supporter Awesome! Thank you to AeroTech for offering new motors! I like that K455 #### Titan II ##### Well-Known Member #### JohnCoker ##### Well-Known Member The M2050X is a reload according to the AT Facebook page (75/5120 case) but it's listed as SU. Updated, thanks. #### Alan Whitmore ##### Well-Known Member Updated, thanks. Correct. My mistake. I just noticed it as I was printing out the paper copies of the certification letters. Alan #### School of Rock'et' ##### Active Member Aerotech has the O5280 at 55.44" and thrustcurve has this motor at 149.9cm (59.01"). Anyone confirm which length is legit? #### AeroTech ##### Lifetime Supporter TRF Lifetime Supporter The casing is 55.44” long. Aerotech has the O5280 at 55.44" and thrustcurve has this motor at 149.9cm (59.01"). Anyone confirm which length is legit? #### School of Rock'et' ##### Active Member Much appreciated!!! #### AeroTech ##### Lifetime Supporter TRF Lifetime Supporter Not quite. A little more sustainer propellant, a little more total impulse. Yes, K455 is same as the K375 reload. Compare on thrustcurve.org #### Nytrunner ##### Pop lugs, not drugs The casing is 55.44” long. Is that dimension from forward lip of thrust ring to end of threaded forward closure? (and will there be dimensioned drawings of the O5280X available on the AT document pages at some point in the future?) #### Nytrunner ##### Pop lugs, not drugs Duplicate post #### AeroTech ##### Lifetime Supporter TRF Lifetime Supporter No, that is the casing only. The thrust ring is 0.50" long, and the end of the threaded closure protrudes 1.36" beyond the end of the casing. Are there any other dimensions you need? There are no plans yet to post the DMS assembly drawings on the website. Is that dimension from forward lip of thrust ring to end of threaded forward closure? (and will there be dimensioned drawings of the O5280X available on the AT document pages at some point in the future?) #### Nytrunner ##### Pop lugs, not drugs Thank you! No that's all i need. That overall internal length is very valuable. Now i onow that any rocket planning to use the O5280 needs 55.44-.5+1.36" between thrust point and whatever volume is needed for recovery hardware (hardpoint, eyebolt in closure, harness, etc...) #### Winston ##### Lorenzo von Matterhorn Wow!! That O-motor is amazing!!! Price....$1999.00
I'm always grateful when others burn large sums of money to entertain me in the process of entertaining themselves.

#### grouch

##### Well-Known Member
That H169 looks like fun. I will have to pick up a few. Not to be nit picky but I wished a RMS version would follow shortly. I don't mind using the SU but I have all these pretty cases that need love too!

#### HVArcas

##### Well-Known Member
That H169 looks like fun. I will have to pick up a few. Not to be nit picky but I wished a RMS version would follow shortly. I don't mind using the SU but I have all these pretty cases that need love too!
superwhite is great!

#### HVArcas

##### Well-Known Member
Not quite. A little more sustainer propellant, a little more total impulse.
does it match the 54/2800 length or is it a one-off size?

#### AeroTech

The single use case is 25” long compared with the RMS case which is 23.45” (not including the aft closure and the flange portion of the forward closure).

does it match the 54/2800 length or is it a one-off size?

#### Alan Whitmore

##### Well-Known Member
Thank you!

No that's all i need. That overall internal length is very valuable. Now i onow that any rocket planning to use the O5280 needs 55.44-.5+1.36" between thrust point and whatever volume is needed for recovery hardware (hardpoint, eyebolt in closure, harness, etc...)
I just noticed this series. I apologize for not replying sooner. Back in '17, Mark Koelsch and I decided to report motor length in this way: We would first measure the entire assemble from the front of the most forward piece, usually the tip of the forward bulkhead. This is reported as the overall length. Then, we would measure from the forward edge of the thrust ring or aft closure up to the tip of the front end. This is the dimension that must exist between the aft thrust plate and any solid object or bulkhead within the rocket, or the motor will not "fit" with the thrust ring sitting on the aft thrust plate of the rocket. Then, we measure from the front of the thrust ring back to the aft tip of the nozzle. This is how much motor hangs out of the back of the rocket.
For the AT O5280X, the OAL is 59", thrust ring forward is 56.938", and thrust ring aft is 2.063".

We never actually measure 'casing length' because that does not seem to be relevant for anybody's design decisions.

Alan

#### Nytrunner

##### Pop lugs, not drugs
Thank you for the description. Is that "practical length" from thrust ring forward edge to end of forward closure the length used in the .eng files?

#### JohnCoker

##### Well-Known Member
Thank you for the description. Is that "practical length" from thrust ring forward edge to end of forward closure the length used in the .eng files?
That would probably be a more useful length to include. Mostly we enter the length specified in the cert. document, which probably is itself not consistent.

If anyone wants to collect the "practical length" or maybe "clearance length" for motors, I'll add that field to ThrustCurve.org.

#### Nytrunner

##### Pop lugs, not drugs
If anyone wants to collect the "practical length" or maybe "clearance length" for motors, I'll add that field to ThrustCurve.org.
Sounds like a great data call for us rocketeers stuck in quarantine!

#### Alan Whitmore

##### Well-Known Member
The casing is 55.44” long.
There are obviously a lot of ways to report the length of a motor. Aerotech reports casing length in their official documents and in the catalog. TMT has decided that the main reason to know length is for design of rockets and for already built rockets, to decide whether a given motor will fit in that rocket. We measure the distance from the forward edge of the aft closure (or molded-in collar) to the forward end of the part that sticks out the most - forward bulkhead tip or the edge of the ejection charge reservoir, just the fore-most point of the complete motor assembly. Then we measure the distance from the forward edge of the aft closure to the tip of the nozzle. This is the total amount that sticks out of the aft thrust-plate. Then we add both distances to get an overall length, and measure that to check the sum.
So, TMT overall length will almost always be greater than casing length. Different metrics, different numbers.

Alan Whitmore
Chair, TMT