Aerotech 4” DD Initiator CATO-Delay Issue

[achaskin]

Just launched a 5.5lb dual deploy Initiator on an AT H135 for a low test flight of the Altimeter and camera system. Had the main in the booster with motor ejection. The single eject AV bay was set to 500 feet to test the deployment ability with no chute in the payload tube.
Here’s the problem… the 14 second delay had to be drilled to 6 seconds, and when using the AT 8 sec drilling tool only a crumb of delay came out. It was as if the motor already only had 8 seconds in it and only 2 seconds would come off….. the delay was more like 15 seconds after apogee and caused ballistic landing… pics and video coming soon….

what happened?

 

[mikec]

Either the motor was defective or operator error. Do you have experience adjusting DMS motor delays?

 

[bobbyg23]

Just launched a 5.5lb dual deploy Initiator on an AT H135 for a low test flight of the Altimeter and camera system. Had the main in the booster with motor ejection. The single eject AV bay was set to 500 feet to test the deployment ability with no chute in the payload tube.
Here’s the problem… the 14 second delay had to be drilled to 6 seconds, and when using the AT 8 sec drilling tool only a crumb of delay came out. It was as if the motor already only had 8 seconds in it and only 2 seconds would come off….. the delay was more like 15 seconds after apogee and caused ballistic landing… pics and video coming soon….

what happened?

Sounds like your delay drill tool needs adjustment.

 

[UhClem]

Here’s the problem… the 14 second delay had to be drilled to 6 seconds, and when using the AT 8 sec drilling tool only a crumb of delay came out.

Did you use the tool correctly? It sounds like you placed the 4 second end of the tool next to the motor. (2 seconds with washer)

When I have the tool set to 8 seconds and drop it into a delay, I see a gap of almost 1/4" between the tool body and knob.

 

[achaskin]

Either the motor was defective or operator error. Do you have experience adjusting DMS motor delays?

It was my first attempt but it was clear something was wrong…

 

[achaskin]

Sounds like your delay drill tool needs adjustment.

I borrowed a tool… uh-oh

 

[achaskin]

Did you use the tool correctly? It sounds like you placed the 4 second end of the tool next to the motor. (2 seconds with washer)

When I have the tool set to 8 seconds and drop it into a delay, I see a gap of almost 1/4" between the tool body and knob.

I saw almost no gap immediately after sliding it in and it only carved a second off before it bottomed out…no washer, on the 8 second side. Did I use a Cesaroni tool? Was the delay just extraordinarily long in this particular motor?

 

[UhClem]

Was the delay just extraordinarily long in this particular motor?

No. They are all the same length. The location of the top of the delay element is set by the closure. Check the tool calibration.

 

[crossfire]

Did you use a DMS delay tool or the RMS delay tool?

 

[rfjustin]

Delay tool did not do what you expected it to do. More delay material should have been removed it seems for the delay you dialed in. Delay modification can be a bit tricky especially if you are new. Best to ask for help at a launch you are at with more experienced eyes/hands around you.

Good luck for next time, don't give up.

 

[Tractionengines]

Did you use a DMS delay tool or the RMS delay tool?

THIS.....RMS or DMS tool / Motor.

My guess @achaskin used a AT H135-14 DMS motor and used the RMS tool.

The DMS motors need a longer tool to reach thru the ejection charge well to the delay element.

The RMS delay elements go directly against the RMS tool and are drilled before the motor is assembled. (So shorter drill projection.)

DMS uses the "univeraal delay drill tool"
https://www.buyrocketmotors.com/aerotech-universal-delay-drilling-tool-for-dms-motors/
The RMS use the RDDT "RMS Delay Drill Tool" this one for 18-38mm motors:
https://www.buyrocketmotors.com/aerotech-18-38mm-rms-delay-drilling-tool-rddt/
Mike

 

[cwbullet]

Did you use a DMS delay tool or the RMS delay tool?

Very important question.

 

[UhClem]

Did you use a DMS delay tool or the RMS delay tool?

Unpossible as the RMS tool can't get the bit anywhere close to the delay element. You would (hopefully) notice the problem instantly.

The drill bit doesn't stick out from the RMS tool body at all.

 

[crossfire]

Unpossible as the RMS tool can't get the bit anywhere close to the delay element. You would (hopefully) notice the problem instantly.

The drill bit doesn't stick out from the RMS tool body at all.

There you go. Still sounds like wrong tool used.

 

[achaskin]

I absolutely used the DMS tool as the bit protruded quite a bit from the actual body of the tool which was short. The RMS tool is clearly a much longer tool with a no protruding bit. This again makes me question, was it really a problem of the tool be misadjusted? Or a delay grain that was offset and unreachable with the tool?

 

[achaskin]

By the way, thanks for chiming in everyone. I’m now able to narrow this issue down

 

[Tractionengines]

Do you know who you borrowed the tool from? Would be good to let them know to check calibration, if you didn't already.

There are Calibration Instructions, we can point you to, but you/they need the RMS tool body (or a 3D printed stand in from Aerotech) as the setting process can't be done with the DMS tool body.
[Sorry if this is confusing.]