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Nope. No-0. Not the same. Rack rockets with B14s were a lot of fun especially when motors were <$.50 each :)
 
I was curious why Aerotech has both the H13ST and H14ST, since they are both long burn motors and are so similar in specs. Specifically, I purpose designed some rockets for the H13ST that sim OK with it and sim as UNSAFE with the H14ST (longer burn, lower initial thrust - the initial thrust peak is so short it makes a significant difference in the sim results). I was a bit concerned that the H14ST was replacing the H13ST, but the response from Aerotech was they are both production motors and that the H14ST was a purpose designed motor. Since I had to design said rockets as light as possible for the H13ST (and I still need very calm winds to fly them), what would the purpose design of the H14ST be?

Let the cogitating begin. Aerotech, wait a bit to respond so we can ruminate on this for a bit and develop a few wild and crazy ideas.

H13ST 1719936740368.png H14ST 1719936844312.png
 
DaHabes said:
I was curious why Aerotech has both the H13ST and H14ST, since they are both long burn motors and are so similar in specs. Specifically, I purpose designed some rockets for the H13ST that sim OK with it and sim as UNSAFE with the H14ST (longer burn, lower initial thrust - the initial thrust peak is so short it makes a significant difference in the sim results). I was a bit concerned that the H14ST was replacing the H13ST, but the response from Aerotech was they are both production motors and that the H14ST was a purpose designed motor. Since I had to design said rockets as light as possible for the H13ST (and I still need very calm winds to fly them), what would the purpose design of the H14ST be?

Let the cogitating begin. Aerotech, wait a bit to respond so we can ruminate on this for a bit and develop a few wild and crazy ideas.

H13ST View attachment 653952 H14ST View attachment 653953
Click to expand...
H13 has <125g of propellant, H14 has >125g of propellant. FAA Class 1 vs Class 2.
 
Art Upton said:
Humm.. Did Gary design it for a Hamster Dance Launch ?
Click to expand...
"The new H14ST-P DMS high-power rocket motor was designed by Gary Rosenfield, RCS/AeroTech founder and president, after developing the H13ST-P for the Hamster Dance competition at Black Rock Desert, NV during the BALLS-28 launch. The new H14ST-P is capable of reaching altitudes over 20,000 feet with an 18.3 second burn time. This low-thrust, long burn high-power hobby rocket motor has the highest total-impulse of any 29mm long burn high-power rocket motor available."

For more details.....
https://rocket.supplies/proddetail.php?prod=A081400
 
DaHabes said:
Since I had to design said rockets as light as possible for the H13ST (and I still need very calm winds to fly them), what would the purpose design of the H14ST be?
Click to expand...
I think the main reason why the H14 exists is because Gary thought it would be cool. Also maybe because it can theoretically push the H record above 20k feet.
 
Neutronium95 said:
I think the main reason why the H14 exists is because Gary thought it would be cool. Also maybe because it can theoretically push the H record above 20k feet.
Click to expand...

I bought two H14's when they were first released. I also think they are cool. I plan on using them for upper stage motors.

My doctor says I need to take more long walks.... flying these will force me into doing that! 😜
 
Casey Andre said:
That was mine, I am almost 100% certain the issue was the ignition method.

In the past I have flown the rocket on 3 x K695's, and it was suggested I use pyrodex to ensure all three motors ignite quickly to be sure the rocket was moving fast enough when it left the launch rail. This advice has worked great for multiple flights on K695's. Some discussions on the field after this years failure make me think I should not have applied this advice to the more aggressive propellant in the K1100's.
Click to expand...
rfjustin said:
I respectfully disagree. I think lack of grain bonding is the root cause of these CATO's. That's just my .02, take it for what its worth. I've clustered (3) K-1100's and (3) K-2050's using the Pyrodex method successfully. Care to guess if the grains were bonded into the liners? :)
Click to expand...
Casey Andre said:
That is interesting. I've flown a decent number of K1100s in the past without grain bonding and never had an issue. It seems odd to me that 3 would suddenly fail for that reason when I haven't had one fail in the past. But I can't blame the pyrodex since you have clearly used that method without issue.
Click to expand...
n3tjm said:
I am curious, why would you want to use pyrodex with blue thunder anyway, it's already a very easy to ignite propellant. Its one of the reasons I collect grains from catoed BT motors, to use as igniter boosters.
Click to expand...

A couple things I have noted over the years (nothing in this post should, in any way, be construed as going against or not following the instructions or advice from Aerotech - just my TTPs):

- I have said this before in this forum and others, but I always recommend checking the liner length of your motors. I had a CATO a few years ago on a K456 and, after a number of emails and photos sent back and forth with Karl, it was determined that the liner was about a 1/4" too short. Karl had me check my other 54mm motors and we found that one of my other K456's (in the same lot as the one that CATOed) also had a short liner. Karl made it right by replacing the case, the reload and sent me a liner for the unused K456. This led me to check all my liners from then on. I have been told by many people that they don't want to spend the time to check liner lengths, that I am just paranoid, etc. I fully understand their point of view, however, I feel like the time is worth it for me. This is not to say anything bad about Aerotech - they have always given me wonderful customer service and, over the past 40+ years, I have literally flown thousands of AT motors. I trust them implicitly. But, like any process, an error can creep in sometimes, so, I feel like you should always check ALL the components of your motor every time you fly one. For me, a couple years ago, I made a simple jig out of piece of aluminum angle with all the AT liner lengths etched on it (probably took me an hour to make and the cost is minimal). Now, I can pop a liner on my jig and, if the liner is close to the line, good enough. It adds maybe 5 seconds to my time to build a motor.
- If the liner is too short, it will almost definitely cause a CATO. If the liner is too long, you can sand it down to length. If you load the liner in the case when it is too long, at least make sure the forward closure is tightly sealed to the case.
- I have been using pyrodex epoxied to my smoke grains (like Justin showed in his picture) for years (although, I admit, I only use a half grain for 38mm and 54mm motors - Justin, full grain on 54mm, wow!). One thing I have found is that the pyrodex method is very hard on the aluminum seal discs. I have a number of the aluminum discs with decent sized chunks missing after using a pyrodex initiation. I know the stainless steel discs are expensive, but I believe they are very, very much worth it if you use pyrodex. I have some of the SS discs that have been exposed to 20 flights using full pyrodex pellets and, aside from some coloration, they look almost new.
- I am with Justin on this and have mentioned it many times in other posts - I basically grain bond (to the liner - not end to end) all my 54mm and above motors that have more than 2 grains. For 75mm and 98mm, I just grain bond everything. Is it overkill? Definitely. All it wastes is a bit of my time and a little glue. But, it gives my paranoid mind some comfort. As far as I know, grain bonding everything won't hurt anything. For me, it also makes it way easier to store the motors, rather than keeping around all the boxes and tubes. I grain bond all my motors as soon as I get them, seal the ends of the liner with tape and plastic (with the nozzle in place so it is ready to go), label them and store them on a shelf in a climate controlled area (i.e. - not out in the hot, humid shed or garage). Yes, many people have told me I am wrong for doing this since the grains have now been exposed to the air, so I am not telling anyone else to do this, but it has worked for me for many years and I have flown many motors after they sat on a shelf for years.
- As for the question about "why would you use pyrodex?" - the short answer is: clusters and air starts. For single motor initiation on the pad, do whatever you want. If the motor doesn't light, try again. I do use pyrodex on the pad for single motors, but that is because I like the reliability of the initiation method. However, on rockets with multiple motors (cluster, staging, air starts), it is vital that all motors start immediately upon initiation. I am a firm believer in the ability of pyrodex to initiate my cluster and air start motors on a dime.
 
I have good results using pyrodex pellets to help start motors. Usually not necessarily with a First Fire, but works great with an ematch.

I use pyrodex because it's convenient and safe. I suppose if I had a wooden spark proof form and remote hydraulic press etc I could make my own BP pellets. Advantage being... Um, not sure, heat, pressure? Anyone know?
 
Last edited:
mtnmanak said:
- I have been using pyrodex epoxied to my smoke grains (like Justin showed in his picture) for years (although, I admit, I only use a half grain for 38mm and 54mm motors
Click to expand...

There are several sizes of Pyrodex pellets. What size do you normally use for 38mm before cutting it in half?
 

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