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54mm spacers ETA? I had to scrub a planned motor this weekend because I'm still waiting on hardware that was ordered in November.

+2.... One of my LDRS flights couldn't use the motor I wanted. Mine have been on order with Wildman for about 7 months.
 
I sent a Facebook message to them but may take a while for a response. 1. I'm pretty sure their at a launch. 2. Memorial Day. I'll post when I get a response.
 
Charlie,

Now that the Q-Jet C14s and D16s are certified, when are they going to be for sale on the Quest site (and elsewhere)? The A3s and B4s are starting to get out into the supply pipeline, which is good news.
 
Also, what is the maximum "no fire" current of the FirstFire Micro initiators? I'm wondering if they are safe to use with a launch control system that uses an incandescent lamp as a continuity indicator (older Estes Electron Beams and such - as well as my club's 10-channel panel) - currents around 150 mA.
 
Still no response from AeroTech on the 54mm reducer system. Hint hint AeroTech. Negative response via email and Facebook [emoji20]
They are swamped with orders so Charlie has not been active here or Facebook as his time has been spent I'm shipping and production. I'll ask him to see if he has an ETA on the 54mm Ras.
 
Recieved this response:

[h=3]AeroTech Customer Service <[email protected]>[/h]
8:12 AM (2 minutes ago)
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We are waiting for the 54mm Floating Forward Closures from our machinist. These are expected in the next few weeks and the 54RAS will be shipping to dealers.


Customer Service





 
Recieved this response:

[h=3]AeroTech Customer Service <[email protected]>[/h]
8:12 AM (2 minutes ago)
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to me
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We are waiting for the 54mm Floating Forward Closures from our machinist. These are expected in the next few weeks and the 54RAS will be shipping to dealers.


Customer Service







Is the Floating Forward Closure that comes with the RAS the tapped one ?

Kenny
 
Quick question about AT 38mm delay grains physics:
I was in the process of building a few motors after a busy launch weekend, and figured my G67R-14A can benefit from delay grain swap with H73J-10A. That way I don't have to drill delay down on G67, and wont have to worry about early ejection on H73J. H73J does come with 14-second delay variant, but I only have 10-sec delay motors on hand.

So I took G67R-14A of the packaging (see pic below), and observed an opposite of what I expected to see - the 14A delay grain from G67 (on the left) is physically shorter than the 10A delay grain (on the right).

  • About 16mm length and 15mm delay grain cylinder diameter for 14A.
  • About 20mm length and 15mm delay grain cylinder diameter for 10A.
  • Which is the opposite of what I had expected to find.

This suggests that the length of delay grain is not the only variable that effects the time it takes for it burn through ?
Perhaps, Redline G67R (1.6s propellant burn, 110 Ns total impluse) burns hotter, and burns through its delay grain faster than Black Jack H73J (2.6s propellant burn, 186.5 Ns total impulse) ?

Long story short, delay grains and time ratings appear to be propellant specific - something new I learned today.
Confirmed here: https://www.aerotechstore.com/index.php?main_page=index&cPath=45_44_47

Can anyone provide further insight into the physics behind this?

Thanks,
a
 
Delay grain compositions are propellant dependant, each propellant type has either different formulation delay grains or different lengths. So they are not necessarily interchangeable on motor to the next. You have pretty much touched on why the delay grains are different, propellant burn rates, temps, and pressure all affect the burn rate of the delay.
 
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Quick question

Can anyone provide further insight into the physics behind this?

Thanks,
a

AT has different delay formulas based on the
chemistry and burn conditions of the motor propellant

Swapping delays on a certified reload becomes a research flight because unless you know the exact chemical behavior of that propellant/delay combination, you can no longer predict the delay ejection result.

Unless you're Tripoli L2 at a research launch, don't do this lol
 
I found this link to a bunch of specs about the delay grains. It contains the type and length for each motor and part numbers. Who knows if it up to date.

https://www.aerotech-rocketry.com/c...Flyers_Data_Sheets/aeroTech_delay_lengths.pdf

I agree this is a bad idea.

Your assumption the the delay time is independent of the motor is incorrect too. The delay time is after the motor has burned out and the burn rate before that is dependent on at least the duration and pressure of the prollellent during thrust.
 
DHBarr is correct. They delays burn much more quickly under pressure, typically the FJ motors have the longest burn times in a "family" of reloads and get the "shorter" delay time as there's a limit to how much delay will go into a given forward closure. That is also why the excellent (for small rockets) E11 and F12 come with nothing more than a 5 second delay, while an F39 can have up to a 9 second delay...
 
I am intrigued by the rebuildable 18mm motors. When might that hardware be available?
 
I'm not familiar with Balsa Machining Service and a Google search gives multiple results. Could you provide an email address for Bill. Do you think he has reloads?
 
Wow! I have achieved rocketry heaven. Thank you, I knew as a BAR that I might be given kindness....and I have received it in spades.
 
I purchased some L-1150R reloads and noticed that Medusa nozzle has a single hole drilled in the middle. The outer ones are NOT.
Look at Aerotech's assembly drawing and shows a central hole and 4 outer holes. what gives?
Did they forget to drill the holes?
The one central hole looks like the size for a 54mm motor not enough IMHO for a 75mm reload.

Screenshot_20180613-091420_Adobe Acrobat.jpg
 
I purchased some L-1150R reloads and noticed that Medusa nozzle has a single hole drilled in the middle. The outer ones are NOT.
Look at Aerotech's assembly drawing and shows a central hole and 4 outer holes. what gives?
Did they forget to drill the holes?
The one central hole looks like the size for a 54mm motor not enough IMHO for a 75mm reload.

View attachment 346181
They stopped drilling the outside to allow for the cross loads. The outerholes are not compatible with the nozzle carrier used in cti hardware.
 
They stopped drilling the outside to allow for the cross loads. The outerholes are not compatible with the nozzle carrier used in cti hardware.

Would have been nice to revise the one on their site as L-11560R-Old and create a new one, L-1150R-New.
There are still other motors for sale that either missing from the instruction list, Motor Assy Dwg list or both.
 
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