Open Rocket nose cone question

[qquake2k]

Is there a way to make a custom shaped nose cone in Open Rocket?

 

[K'Tesh]

Depends...

If you are talking about something that is round. Yes.

So an upscale or downscale of a PNC-55AC can be done (Using a nosecone for the blunt section, and a transition to get you the ogive portion (and shoulder)).

If you are talking about something that isn't... No*.

So, those Sci Fi nosecones, and nosecones with canopies. Fuggedaboutit.

*except... Nosecones that are round but have "winglets" on them (e.g. a JayHawk). The winglets can be done with fins attached to Phantom Body Tubes, and are then offset into the correct location.

 

[qquake2k]

I'm thinking about making a crayon rocket, and I want to turn a nose cone shaped like the tip of a crayon. I've been playing around with transitions in Open Rocket, and pretty much have the shape I want. But I don't think OR sees it as a nose cone. In red, in the lower right corner it says, "Warning Discontinuity in body tube diameter". I don't know what that means, and I wonder if the flight simulations and stability are accurate.

View attachment Crayon.ork

 

[rharshberger]

The discontinuity is coming from the difference in the aft diamter or your "nose cone" conical section (forward part) and the transition aft of it, when two transitions or body tubes do not meet at exactly the same diameter the discontinuity warning pops up. To make a crayon nose cone there is currently no way around the continuity warning. As far as the sim, I have done the Fantazia Crayon Bank conversion twice and used OR to sim the flights, they were not too far off iirc the sim.

As for Crayon nose cones....




These are balsa and sized to fit the Estes 3" airframe (BMS T-300 tube). Each 12" block of 3" balsa makes two nose cones (upscaled to be the same as a real crayola crayon, dimensions courtesy of John Cokers website iirc). The pine bases on two cones are there for the drive spur on the lathe to have something tougher than balsa to bite into and will eventually be removed.

 

[qquake2k]

Those look nice. Did you turn those?

 

[blackbrandt]

However, something I have found... if you need to make a flat transition (like the crayon nose cone), you can set the length of the transition equal to something like 0.001" and OR plays a whole lot nicer for you.

 

[qquake2k]

However, something I have found... if you need to make a flat transition (like the crayon nose cone), you can set the length of the transition equal to something like 0.001" and OR plays a whole lot nicer for you.

I don't understand what you mean, Matt.

I bought some crayons, measured one, and adjusted the dimensions. This file is more accurate.

View attachment Crayon.ork

 

[rharshberger]

Those look nice. Did you turn those?

Yes, chisels and gouges for the main shaping then files and sanding blocks for the rest.

 

[Rex R]

one puzzles me about these crayon rockets, banks, etc. is why the section with the label is a smaller diameter than the rest. my crayolas certainly are not that way.
Rex

 

[qquake2k]

I think it's because the tops of the banks fit over the tube. The base of the nose cone I'm planning on turning will be the same diameter as the body tube.

 

[rharshberger]

I think it's because the tops of the banks fit over the tube. The base of the nose cone I'm planning on turning will be the same diameter as the body tube.

The banks nose and tail sections are molded from a polyprpolene plastc material and are only slightly larger in diameter than the tube they go in, the nose and tail pieces have shoulders just like we use in rocketry.

Like you Quake I chose to turn my nose cones to the sam diameter as the air frame, that way the vinyl decals will be the wrapper.