Raven4 question.

[Offbeat]

My first time configuring a Raven to use in flight. I'm using the apogee and main pyro channels only to start. When selecting Apogee Pyro Channel "At Apogee (Barometric)", the check box for Velocity < Vel1 is also selected by default implying the pyro channel will fire if velocity falls below Vel1. Vel1 is set to 400 ft/sec (about 272 mph) by default which seems high to me. And especially for the main pyro changer which is at the same default.

Question is, should this parameter be reduced in speed or even unchecked which creates a custom pryo channel? Thoughts and opinions are appreciated.

Thanks

 

[OverTheTop]

My experience with Ravens is that the factory default settings are usually right for most people, probably 90% of the time. If you are considering changing anything try to think what the default setup gives the user, and if it is any advantage to you.

I normally fly default, except for the complex flights.

 

[kjs]

My first time configuring a Raven to use in flight. I'm using the apogee and main pyro channels only to start. When selecting Apogee Pyro Channel "At Apogee (Barometric)", the check box for Velocity < Vel1 is also selected by default implying the pyro channel will fire if velocity falls below Vel1. Vel1 is set to 400 ft/sec (about 272 mph) by default which seems high to me. And especially for the main pyro changer which is at the same default.

Question is, should this parameter be reduced in speed or even unchecked which creates a custom pryo channel? Thoughts and opinions are appreciated.

Actually that 400 is the protection against mach effects on the air pressure (it prevents it from firing when going through mach transition which can cause the pressure to suddenly start increasing making it otherwise look like it is past apogee and descending). So those check boxes are a AND logic. So basically it is saying it needs to be less than 400 ft/sec (as calculated from the accelerometer - again just for mach 'lock out') and pressure increasing (just past apogee).

Let us know if you have further questions!

/kjs

 

[HHaase]

I'd also leave it alone too. KJS gave a great reason that doesn't get thought about often. You also need to plan for flights where things are not going to plan and you're outside the expected performance.

My understanding is the VEL1 is velocity along the rocket axis, not vertical velocity. So it is actually quite possible to hit apogee and still be moving along at a good clip if you arc over with a more parabolic flight path. This is pretty common for rockets that look something like airplanes, such as BOMARC's. They start acting like gliders if there's wind. Or really anything with a lot of fin area can weathercock a lot and go parabolic to a degree.

For the main deployment, again it may seem too much, but I can still see situations where it's warranted. A heavy rocket under a streamer drogue for instance. Or maybe a case where the drogue didn't deploy for some reason and you're coming down faster than expected, you REALLY want that main to fire in a situation like that.

I use the defaults almost exclusively, and my Raven 3 has never failed me.

 

[kjs]

I use the defaults almost exclusively, and my Raven 3 has never failed me.

I have always used the defaults also and my only issue was years ago when we changed the main deployment from accelerometer based to barometric based and I had my Raven (2?) in a sealed nose cone...!

 

[Offbeat]

Actually that 400 is the protection against mach effects on the air pressure (it prevents it from firing when going through mach transition which can cause the pressure to suddenly start increasing making it otherwise look like it is past apogee and descending). So those check boxes are a AND logic. So basically it is saying it needs to be less than 400 ft/sec (as calculated from the accelerometer - again just for mach 'lock out') and pressure increasing (just past apogee).

Let us know if you have further questions!

/kjs

Perfect, thank you.

 

[TonyL]

It would be nice if there was an acceleration based apogee 'default setting' button. Mis-configuring my raven helped get me a very expensive crater one time. I am not blaming the raven, but had the other parts of the system worked, then that would be the next independent failure [i.e. my mis-programming] in the fault chain.

 

[Adrian A]

It would be nice if there was an acceleration based apogee 'default setting' button. Mis-configuring my raven helped get me a very expensive crater one time. I am not blaming the raven, but had the other parts of the system worked, then that would be the next independent failure [i.e. my mis-programming] in the fault chain.

There is an accel-based apogee pull-down menu option, called "At Apogee (Accelerometer)"

 

[kjs]

Yes, there is a list of default options in the drop down, as well as a button to reset a unit to the factory default.

 

[TonyL]

ah ha...