ANNOUNCEMENT: OpenRocket version 22.02 Final is now available for download

[neil_w]

I like that, but I note that the units options also allow for displaying stability as a length in meters, centimeters, millimeters, or inches. I have no idea if anyone actually uses those options, but in case there are users who prefer to see length, would it make sense in your example to show stability as "5.15 cal / 15% / 644mm," with the unit depending whether the user chose metric or imperial?

You're right, and somehow I missed that when I was bouncing around looking at a bunch of different stuff. I don't know if anyone uses those options either. Unfortunately we have no way of knowing.

Showing three different measurements at once is (IMHO) pushing things too far. Possibly we will just ask for primary and secondary units, and show both. I'd prefer fewer preferences but in this case I guess I don't see any way around it.

 

[bad_idea]

You're right, and somehow I missed that when I was bouncing around looking at a bunch of different stuff. I don't know if anyone uses those options either. Unfortunately we have no way of knowing.

Showing three different measurements at once is (IMHO) pushing things too far. Possibly we will just ask for primary and secondary units, and show both. I'd prefer fewer preferences but in this case I guess I don't see any way around it.

Not sure if you caught my edit or not. Since it's on the last page, I'll repeat it here:

You could change the"Stability" preference to "Stability units" and set it to "none" as default and allow people to choose in/mm/whatever if they desired. (Cubits for me.)

 

[kjhambrick]

Another 'How Do I' question about OR ...

I am dusting off a modular rocket system designed around a set of scaled Vulcanite H76 Fin Cans, AV-Bays, Recovery Tubes and Transitions.

I want to create a model in OR where say, I mate a 24-mm Sustainer to a 29-mm Booster, etc, etc, etc ...

My Question is ... how do I tell OR to overlap the 29-to-24 mm Transition just a tad higher on the Sustainer Fin Can ?

Attached is an OR.ork file and a Screen Shot where the Booster-Sustainer Transition is selected ...

In this case, I want to move the Booster-Sustainer Transition up about 0.45 inch from the end of the Sustainer Fin Can.

No worries if it can't be done, just wondering if I am missing an optional Parameter somewhere

Thanks !

-- kjh

 

[neil_w]

My Question is ... how do I tell OR to overlap the 29-to-24 mm Transition just a tad higher on the Sustainer Fin Can ?

Attached is an OR.ork file and a Screen Shot where the Booster-Sustainer Transition is selected ...

In this case, I want to move the Booster-Sustainer Transition up about 0.45 inch from the end of the Sustainer Fin Can.

No worries if it can't be done, just wondering if I am missing an optional Parameter somewhere

In general, there is no way to overlap body components: they always are laid out edge to edge with no overlap and no space. That is why there is no "position" parameter for these components.

There are ways to fake it if it's really important (in this instance it doesn't appear to be.) I wouldn't bother to do any of what's described below, but just for completeness these are the options.

For example: you could simply make the sustainer fin can 0.45" shorter, and then add another 0.45" of overhang to the motor. This means that the full stack will have the correct dimensions, but the sustainer will be a bit short. This will have very minimal impact on the sim.

You could partially correct this by adding a 0.45" inner tube to the end of the sustainer. This will *not* be factored into aerodynamics, but it will restore the correct appearance of the sustainer and also mass/CG (of course, you'll be weighing the sustainer and overriding those parameters anyway after the rocket is built, so it really doesn't accomplish much).

You could get the proper aerodynamic performance by adding a single pod with a 0.45" body tube to the fin can, positioning it so it'll be appended to the tail end of the sustainer. OR has some logic to detect if in-line pods are contiguous with the airframe and should handle this correctly (actually there are some things I need to double-check there, to make sure it really *is* handled correctly; if not it will be fixed).

 

[kjhambrick]

Thanks neil_w

I did look 'real hard' for some sort of linear offset for the Transition and anticipating your reply that it really wasn't there, I went ahead started adding the inner components for the Booster AV-Bay ( there is an inner 26.5 mm I.D. Tube that rides around the tail of the sustainer down to the Upper Bulkhead in the AV-Bay ).

I don't want to mess with the configuration of the Sustainer because that's for the 'Money Shot, after the Booster falls away.

As you said, having the Transition scooted aft 0.45 inch th won't affect the OR Sim except for a teeny-tiny increase in wetted surface area during the Boost Phase and the CG will move aft a tad.

But I've flown a 54 mm -to- 48 mm version of this stack and it's plenty stable.

IOW, no worries !

BTW, I think Y'All have done a wonderful job on OR

Thanks again, Neil.

-- kjh

 

[bad_idea]

I just checked for updates on github and saw this commit:
Add secondary stability unit in preferences

Built it from source, updated my preferences to choose caliber, and now I have percentage and caliber side by side. Thank you @SiboVG and team!

 

[SiboVG]

I just checked for updates on github and saw this commit:
Add secondary stability unit in preferences

Built it from source, updated my preferences to choose caliber, and now I have percentage and caliber side by side. Thank you @SiboVG and team!

My pleasure!

 

[RocketScientistAustralia]

Does OR take into account a radially off-centre weight for trajectory calculations? Or a single additional fin drag if added on one side. Asking for a friend......