CarVac
Well-Known Member
- Joined
- Feb 12, 2012
- Messages
- 5,704
- Reaction score
- 37
Dude that looks awesome, Alex. Keep it up!
Hey, I was saying that they look incredibly awesome in the photos.
Dude that looks awesome, Alex. Keep it up!
Probably shoulda gone with that phrasing the first time around thenHey, I was saying that they look incredibly awesome in the photos.
The NC tip came with my Wildman 2.1in darkstar. TONS nicer then the ones without the shoulder. I think they're just on the 2.1in ones. To fix your shoulder problem have you tried putting two washers spaced apart on the allthread? The once closer to the tip could have a smaller OD and hypothetically it would center itself.Tell me about that nosecone tip in the photo. I see it has a shoulder on it - UNLIKE any of the tips on my FWFG cones (I have three of them). On mine, it drives me completely insane getting them to go on straight, and/or to stay on straight. I'm talking foaming-at-the-mouth, screaming-and-shaking-my-fist-at-the-heavens kinda nuts. Very frustrating. I wish they had a shoulder on them like yours. So, what's the deal with yours?
On another note: I won't be making it up to the Feb UROC launch - gotta go to the dentist, have him torture me, and take all my money. Way more fun than flying rockets, let me tell ya.
No, it looks just like that in person. It just doesnt feel like you think it should. It might be the way I applied the clear cloat. It didnt spread out evenly but the mist created a slight texture on the tube. It may have been because it was too cold. Once it warms up. I'll sand the tube down with 1500 grit and try again.I understand the need you feel to make it better; flaws in CF rarely show up in photographs so I'm guessing the tube looks less incredibly awesome in person.
Dude that looks awesome, Alex. Keep it up!
Probably shoulda gone with that phrasing the first time around then
It's too bad it's so pretty... now the rocket gods have that much more reason to give Manny's motor a hard time!
Well now I'll have to think up some excuse for lawn-darting your case!I promise you Alex, there is a 99% chance your rocket won't CATO. If I find problems while testing the motor, there is always plan B.
For standard tube sizes you can use a full length coupler that would fit the desired tube ID.Regarding CF layup for tubes, how do you source accurately sized mandrels? S'there a place that carries workable tooling for a reasonable price, or do you need a lathe?
is that stability information coming from openrocket or from RASAero?I was going over this design with Ryan (FrozenFerrari) and he pointed out that I was very overstable after motor burnout (3 cals or something). This could result in serious issues like weathercocking, coning and others. Not ideal.
I spent a few days reworking the design entirely. The fins will have to be shortened and instead of standard dual deploy, I'll be doing the same thing as my Peacemaker (Deploying out of the NC using a cable cutter) This is all to lower stability at low mach numbers.
With the revised the design I am now at 2.37 cal with an empty case and .6 cal at Mach 2.5 (estimated max speed). I'm estimating the limit for this is Mach 2.8.
Here is the redesigned file:
View attachment 164652
I'd appreciate feedback on the design and what changes I can make to improve it.
Alex
is that stability information coming from openrocket or from RASAero?
This project has been pretty impressive throughout, but seeing these fincans and your methods, you've clearly moved onto a new level of craftsmanship. Awesome, man! https://d24w6bsrhbeh9d.cloudfront.net/photo/aEwp1pn_460sa.gif
I agree with your reasoning for choosing JB weld over the Proline; I've found multiple datasheets of the proline that were contradictory, and I've never really found a manufacturer that makes it; only retailers for it. Without reliable data, it's a little frightening to use, even though lots of pros use it. My experience with Jb weld has been strictly positive, with one exception; it's a little brittle. Hopefully it isn't a problem for you; with fins that stiff and small, it shouldn't be.
The fin material you have is sort of made from cloth, just not woven cloth. The panel is made by taking unidirectional fabric (something like this https://i01.i.aliimg.com/photo/v1/280156977/carbon_fiber_prepreg_prepreg_carbon_fabric_prepreg.jpg) and adding layers at 90 degrees away from the layer before.
Some of the differences relative to a panel with an identical number of fibers in each direction made from woven fabric:
- Lighter weight: flatter layers of fiber mean it probably has a lower amount of resin.
- Probably thinner: maybe, but by the same reasoning as the lighter weight argument, the panel could be thinner than an equivalent woven-cloth panel. This means it might be less stiff by a tiny bit.
- Possibly stronger-no fibers are pinched in the over/under pattern, since there isn't one. I don't know if this is really a big deal, but when I've snapped CF weave panels, they crack at the over/under points.
- The all-uni panel will probably fail by delamination, where the UNI layers split apart. Woven layers have regions where fibers in layer n of the laminate and layer n+1 are touching and in the same direction, which bonds the layers of fabric together better.
*Disclaimer: I think you made a great choice of fin material, just thought I'd provide some (possible false) information on the material.
Thanks, Captain!Qquake2k said:That sure looks sleek, Alex!
I had a feeling you guys were getting bored, so how about a paint teaser to liven things up?!?
Alex
I had a feeling you guys were getting bored, so how about a paint teaser to liven things up?!?
Alex
Enter your email address to join: