Picking the delay for Quest Q-Jet model rocket motors

[BRS Hobbies]

Recommended motor for a particular model rocket -

C6-3: C12-4, D16-6
C6-5: C12-6, D16-8
C6-7: C12-8

I know it's best to do a sim but do you guys think this would be in the ball park in regards to picking the correct Quest Q-Jet delay for the C12 and D16?

 

[shreadvector]

Recommended motor for a particular model rocket -

C6-3: C12-4, D16-6
C6-5: C12-6, D16-8
C6-7: C12-8

I know it's best to do a sim but do you guys think this would be in the ball park in regards to picking the correct Quest Q-Jet delay for the C12 and D16?

Semi correct, but I would use the D16-4 for the C6-3 and D16-6 for the C6-5 and the D16-8 for the C6-7.

8 real world seconds is a LONG time and is longer than the actual "5" or "7" in the C6-5 or C6-7. Crashing is "BAD". Choosing too long a delay is a common error.

Here are the actual tested delay times for Estes C6 motors on the NAR S&T website Estes C6 data page:

 

[5x7]

Semi correct, but I would use the D16-4 for the C6-3 and D16-6 for the C6-5 and the D16-8 for the C6-7.

8 real world seconds is a LONG time and is longer than the actual "5" or "7" in the C6-5 or C6-7. Crashing is "BAD". Choosing too long a delay is a common error.

Here are the actual tested delay times for Estes C6 motors on the NAR S&T website Estes C6 data page:

View attachment 390425

Is that data from 25 years ago? Never mind, it’s 24+ years old.

 

[dpower]

Recommended motor for a particular model rocket -

C6-3: C12-4, D16-6
C6-5: C12-6, D16-8
C6-7: C12-8

I know it's best to do a sim but do you guys think this would be in the ball park in regards to picking the correct Quest Q-Jet delay for the C12 and D16?

I agree with Fred:

C6-3: C12-4, D16-4
C6-5: C12-6, D16-6
C6-7: C12-8, D16-8

My real world flights are consistent with this, I’ve flown a bunch of the -4/-6 QJets.

 

[Joekeyo]

My open rocket does not have D16s as an engine choice. Is there anyway to add them.

 

[neil_w]

https://www.rocketryforum.com/threads/how-to-add-a-motor-to-openrocket.123622/#post-1869147

 

[Bill S]

This is a great thread. I plan to use more of the Q-Jets when I am able to launch again.

 

[msjohnso]

Semi correct, but I would use the D16-4 for the C6-3 and D16-6 for the C6-5 and the D16-8 for the C6-7.

8 real world seconds is a LONG time and is longer than the actual "5" or "7" in the C6-5 or C6-7. Crashing is "BAD". Choosing too long a delay is a common error.

Here are the actual tested delay times for Estes C6 motors on the NAR S&T website Estes C6 data page:

View attachment 390425

Historically, "Estes Seconds" have always been a bit short...partly because of the difference in BP motor performance at 5000 MSL where they are made, and 15 MSL where S&T tests them. BP burns slower at lower ambient pressure...and also has a lower Isp. I'm not sure if there are any test results for composite motors...