Ramjet Nose Cones & RocSim

[Hospital_Rocket]

Is there a way to create a nose cone part in RocSim? I have started my RIM8 Talos and want to model the performance. I would expect the draggy NC (considering that it is all but a blunt surface) would need to be created.

A

 

[sandman]

Al,

I just did this one real quick like.

Start out with the ram jet intake tip as a transition. You have to give it a tiny front diameter like .01".

Then do another transition right behind it.

I made the tip "transition" conical and the rest of the "cone" an ogive.

It wasn't too hard.

 

[Hospital_Rocket]

Can you turn something like this? that is after the earrings are done...

BTW - neat presents.

 

[sandman]

Sure I can!

Just email me the particulars...body tube, cone length, intake length, shoulder length.

And quantity.

A drawing (sketch) would be helpful.

Not sure when...it's currently 1 degree out and my furnace in the shop is pretty useless at these temperatures.

 

[teflonrocketry1]

I touched up Sandman's RockSim file a bit see attached. I sim'ed the RamJet nose cone as a nose cone and two transitions. This doesn't affect the Cd much but the CP moves forward! If you sim' the nose cone as a blunt cone only (say power series with shape control at 0.10) you will see the CP move up to where it is in the file I attached.

Bruce S. Levison, NAR #69055

 

[sandman]

OK...here is my first try.

It's made for a Totally Tubular T-2.04" tube (old Centuri size!).

This was done "freehand" on the lathe "re-turning" a "mistake" nose cone that was a bit too small for a BT-70.

Now you guys know what I do with my mistakes!

 

[sandman]

I tried a few more just for fun.

These are BT-60 sized.

 

[Fore Check]

Another quick and dirty method I've used to model the nose cone of this rocket on RockSim follows:

Start with a nose cone. Make it conical, with the height and base diameter being appropriate for your scale for the tip part of the ramjet. Make the shoulder diameter and length be as small as is allowed by Rocksim (either 0.01 or 0.001)

Then make a transition. The forward shoulder will be the same as above, as small as is allowed. The front diameter is scaled for your model, and the lower diamter is the size of your upper airframe tube. Make the length be according to scale, and choose an "ogive" shape. Make the rear shoulder appropriate for your model (to fit your upper airframe tube, and an inch or two in length.)

Whether or not this will give you exact aerodynamic data in flight simulations, it sure looks right in the 2D and 3D renderings.