Estes sky writer question

I'm hoping to fly the Sky Writer tomorrow on Quest A3-4 Q-Jet rocket motor with an APRA altimeter in the nose cone.


Will the A3-4 have enough power to lift the Sky Writer with an APRA altimeter inside it?


Also what do you expect the altitude to be?



I ran a OR simulation and it said 185 ft. I hope it won't go that low! Lol.




Thanks,

What speed off the rod did your sim show, and what total weight?

I actually did it on a A8-3 becuase there is no Q-Jet A3-4 on OR.
The A8-3 sim had it as 35 MPH off the rod.



Thanks,

rockets said:

I actually did it on a A8-3 becuase there is no Q-Jet A3-4 on OR.
The A8-3 sim had it as 35 MPH off the rod.

Click to expand...

Download the *.eng file from here :

https://www.thrustcurve.org/motorsearch.jsp?id=1115

And add it to your OR engine directory, check edit->preferences->User defined thrust curves. After you put the *.eng file into that directory, you'll need to restart OR to see that motor.

Also, no, it doesn't look good, 71ft - 17 ft/s.

cheers - mark

What's the peak thrust of a Quest a3? What's the total weight of your rocket including the motor? How can you use these to satisfy the RSO you'll be marginal in calm conditions?

I don't ask these questions to be a jerk, just trying to help prime the pump.

I doubt any RSO is involved in the equation.

I just did a new sim on OR.
This time simmed the Sky Writer flying on a Q-Jet B4-4.

It simmed to 430 ft. And 35 MPH off the rod.

I'm guessing that's fast enough, right?



Thanks,

That sounds much better

Have you used the thrustcurve website's estimator? It will run every motor that falls in the range you specify and will alert whether it's fast enough (green), risky (yellow), or too slow (red) off of your specified launch guide.

Nytrunner said:

That sounds much better

Have you used the thrustcurve website's estimator? It will run every motor that falls in the range you specify and will alert whether it's fast enough (green), risky (yellow), or too slow (red) off of your specified launch guide.

Click to expand...

I looked at the Estes website, and the Estes B4-4 is a recommended motor, so I'd guess the Quest B4-4 would work as well.

Yep, Thrust Curve says it's fine.

Thanks,

rockets said:

Yep, Thrust Curve says it's fine.

Thanks,

Click to expand...

Ooph, be verrry careful making such assumptions. I made the same assumption once about the Estes C6-3 vs Quest C6-3, and, as a result, my Redstone is missing its tower to this day.

Nytrunner said:

Ooph, be verrry careful making such assumptions. I made the same assumption once about the Estes C6-3 vs Quest C6-3, and, as a result, my Redstone is missing its tower to this day.

Click to expand...

Apparently Quest B4 motors have more power off the pad than Estes B4's do.



Thanks,

The quest c6 motor you used was really somewhere between a c3 and a c4