elliptical nose cone for upscale design

[bcook7135]

I am trying to design an upscale of the Estes Astron Sprint XL. And, I really want it to be as scale as it can which would require an elliptical nose cone. At 2X size, it would be a 3" nose cone diameter with about an 11" length. But, I can't find any manufactured elliptical nose cone that size.

Is a 3D printed one a good option? I have bought some 3d printed parts for other rockets (never a nose cone) and they were pretty rough in texture. Is that typical for 3D printed items?

 

[tsmith1315]

Is Gordon still at it?

http://roachwerksmachining.com.istemp.com/

 

[Pepe Le Pew]

Hi Bcook7135,m I can print one for you. I need the exact measurement of the diameter of the nosecone itself and not the shoulder. Let me know.

 

[bcook7135]

3.1” diameter
Cost?

 

[Pepe Le Pew]

No cost. Just pay the shipping. I'll let you know when I get it printed, it's a 12 hour print. Pics tomorrow.

 

[Pepe Le Pew]

bcook, the base that is going into the tube is 76mm. Will this fit your tube?

 

[bcook7135]

I need to measure but I think it is 75mm

 

[bcook7135]

Yes it is 75mm

 

[bcook7135]

Do you know what type of plastic it is? I need to glue in some nose weight.

 

[bcook7135]

Thought you might want to see the finished build.
Thanks!

 

[Rschub]

It's beautiful. I really hate to be that guy, so I wont be. Happy flying!

 

[bcook7135]

Thanks

 

[RokitFlyr]

It's beautiful. I really hate to be that guy, so I wont be. Happy flying!

It may just be the camera angle.......

 

[bcook7135]

Uh oh. What is amiss?

 

[Pepe Le Pew]

EXCELLENT JOB!!! I cant wait to see it flying! Well done.

 

[Pepe Le Pew]

It is PLA, poly-lactic acid. Use an adhesive that does not exotherm hard (5 min epoxy).

 

[bcook7135]

EXCELLENT JOB!!! I cant wait to see it flying! Well done.

Thanks

 

[bjphoenix]

Looks great to me. I am finishing an upscale to BT55 dimensions, using a nose cone from a Goblin.

I don't see any big problems with your design. The tail cone looks a bit short, and it's chrome instead of white, but If you aren't building the original kit then sometimes you have to accept minor differences. If it still looks like a Sprint then why worry, the object is to make it look like a Sprint.

 

[bcook7135]

Tail cone is short. Using an aluminum cone retainer from Aeropack. That was a big concession I made. And I didn’t want to paint it. Another concession. I want to have a part to be highly reflective in the sun for tracking.

 

[bjphoenix]

Tail cone is short. Using an aluminum cone retainer from Aeropack. That was a big concession I made. And I didn’t want to paint it. Another concession. I want to have a part to be highly reflective in the sun for tracking.

My upscale Sprint is waiting for its final paint touches. It is built for 18mm motors but with its pretty tail cone I didn't want to integrate an engine hook so it will have to use friction fit like we used to use way back when. (It's upscaled from BT50 to BT55, I realized that "upscale" and "18mm" don't quite go together in this subforum.)

 

[bcook7135]

Ahh yes. I well remember my original Sprint. I didn’t trust the friction fit and used masking tape on the outside of the motor mount and engine.
Will you have streamer recovery?

 

[TRWXXA]

It is PLA, poly-lactic acid. Use an adhesive that does not exotherm hard (5 min epoxy).

That is a beauty! The elliptical nose cone is important to the look of the rocket, just as much as the elliptical fins. I'm upscaling my favorite, childhood rocket -- the Sprint. Is it possible to upscale the NC to a 4" base diameter. I forget the exact length, but it's something like 15". Could a NC be printed in 2 pieces, with a shoulder on the lower half, and epoxied together?

 

[Pepe Le Pew]

Hi TRWXXA, I may be able to print it in one piece, I'll let you know. Also I can print in PETG which tolerates hot days better. PLA will melt and deform in the heat of a car or direct sunlight if it is painted a dark color. Give me a few and I will let you know.

 

[Pepe Le Pew]

Ok, I can print it in two parts and bond it together at the shoulder. What I need is an exact measurement of the OUTSIDE diameter of the tube in millimeters. I use both Staples 4" tubes (8 bucks) and LOC tubes (16 bucks). they are slightly different in size but the tube thickness is the same. All my mid power stuff is staples tubing.

 

[TRWXXA]

J.R.

I have it designed out for PML, "3.9" kraft-phenolic tubing. PML uses the I.D. for their tubing labels, so it's actually 4.024" O.D.(102.2mm). The I.D. is 3.90" -- 99.1mm.

The nosecone length for a 4" upscale, is 13.4", or 340.4mm -- tip to base. Then the shoulder is another 90mm long with a 99mm diameter.

If the limiting length, includes the shoulder, then the shoulder could be eliminated with the use of a tube coupler, if the 99.1mm coupler could be inserted into the NC about 1..25 to 2 inches. That would also allow easy construction of a nose avionics bay.

Chris

 

[Pepe Le Pew]

Let me work on this during the week Chris. I bet we can get it to work!!!

 

[TRWXXA]

Let me work on this during the week Chris. I bet we can get it to work!!!

Thanks, J.R.!

No hurry. This project has been on the shelf since the ATF chased me out of the hobby 23 years ago. I thought this would be a good project to dust off and use for my L2 recertification.

Many things have changed in the last 2+ decades, but surprisingly, you still can't find an elliptical, or good rounded-ogive (Red Max or Goblin) nosecone in HPR sizes.

C.

 

[SolarYellow]

The Mega Red Max cone is available, or was last week, from Estes as a standalone part.

 

[TRWXXA]

The Mega Red Max cone is available, or was last week, from Estes as a standalone part.

I see that they have it. No idea what the specs on it are, and if it will fit HPR tubes or could be modified to fit.

 

[SolarYellow]

There's a thread about it here somewhere that shows it fits LOC tubing, which also implies it fits AeroTech tubing.