CF Optima MAC Performance ( Fins on!)

The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Curious why you put the aft ring and retainer on before mounting in the body. I always leave the aft ring for after the fins are on.

Mostly spacing and laziness/reducing steps. I could dry fit it, glue the front two CRs, and leave the back open. I did leave the rear CR off on Emerald Dragon, my MAC Villain, and several other rockets. I found with as tight as the MMT to BT spacing was I didn't get very effective fillets internally.

Typically now I'll do one of two things-
Install the full MMT with CR's spaced to sandwich fin tabs, and inject after the fins are tacked into place. Did this on my Wildman, Darkstar, and wild man Extreme.

or, inject a ton of epoxy into the fin slot, butter the edge of the fin, and press it in. I prefer this method now. Did it on my Screeches, Villain, and Zodiac.

I did add some small internals on the Villain, but they weren't great, and some I totally missed the joint. But I still needed a sledgehammer to break those fins out.


Then again.... I've been wrong before.
 
Last edited:
Not many photos of this step. I used a skewer to put a thin bead of epoxy just above the upper fin slots, inside the tube. Then, a small bead was placed around the step of the lower CR. Slid it all together, and then wiped off the excess epoxy on the bottom CR.

Fin slots are all clear.

26870546939_9edcdf8924_c.jpg
 
Yep, still alive...barely.

Sanded the first set of fins ever so slightly, and not above the BT line yet. I'll sand them all with the BT just before doing external fillets.

Aeropoxy ES6209 was then buttered onto each fin generously. The fin was then held with the root edge down, and the epoxy let droop down. When the "droop" was the width of the slot, in she goes.

x3

38949502071_3d92d8a339_c.jpg


Currently curing in a vertical position.
 
So, I've got a general idea how I'm going to do this. I think.

Wondering how you'd all do it. Plan is to use the XTRA to pop the nose at apogee, and a JLCR to release the main.

How would you glue, screw, stick and tuck it all together?


25176867948_c6bdc521d1_c.jpg
 
So, I've got a general idea how I'm going to do this. I think.

Wondering how you'd all do it. Plan is to use the XTRA to pop the nose at apogee, and a JLCR to release the main.

How would you glue, screw, stick and tuck it all together?


25176867948_c6bdc521d1_c.jpg

Probably use a customized sled of some sort. I'm guessing that the all thread spacing matches perfectly with the bolt spacing on the AIM. Also going to need a better battery holder for the LiPo's.
 
I would go with setup Justin mentions in his earlier post. Do everything out of NC coupler/av-bay. K.I.S.S.

Get a longer coupler to get your Aim inside, vent band. Blow apogee from bottom & main out of NC shear-pinned on coupler. You may need to ditch the sled. [don't know how/if your aim fits] Cut/grind the excess from eyebolts sticking into bay.

I did it here with same cone and altimeter /lipo on one side & GPS on other. I did order a longer coupler and vent band. Get vent band fiberglass to aid in RF transparency. This should keep your GPS above the carbon & you are good to go!

https://www.rocketryforum.com/showt...t-Drag-Race-35-00-build&p=1586802#post1586802
 
Last edited:
Interesting thoughts. Not sure I can get a chute in the tiny nose. Still considering options there... I do like having a vent band.

Finally got the fins on.

27340493109_e6ec4b03ee_b.jpg


24257990327_23481f486c_b.jpg


27341095739_b874561883_b.jpg
27341086899_91214447ac_b.jpg
 
Put some blue and/silver markings in key places such as where the orange/silver markings are at on the Optima. Maybe paint the fin bevels. Then it would look "finished" without hiding the CF.
 
Last edited:
Do I paint this as an Optima or a Shadow?

Paint? :no:

Put some blue and/silver markings in key places such as where the orange/silver markings are at on the Optima. Maybe paint the fin bevels. Then it would look "finished" without hiding the CF.

LOL Can't get one past you guys.

I've got sheets of green, orange, and blue metal flake, and a ton of chrome. This is the green and blue metal flake on a Pheonix. I lean toward blue or green on this.
5891756682_f4a2ba136d_b.jpg



I'm not sure If I'd do any on the fins. If I do I'll likely only do one, as I did on these BT-60 downscales-

7253489402_176ac08a8a_c.jpg



7253494004_8584337bd9_b.jpg


The white nose is actually kind of growing on me.... I do like/want a total clear coat with minimal accents, but that ones on the table for now.
 
Last edited:
....just a bit of contrasting trim color and logo and clear coat on that gorgeous carbon fiber
 
48788166841_75e3c378f7_c.jpg


12.5 grams of resin, 2 grams of hardener (proline 4500)

48788165786_930e33056e_c.jpg


All taped up and fillets laid in. Pulled with a 3/4" pipe in back, and fingertips up front.

48787803778_b317495591_c.jpg


Leveled.

48788165146_e5291ce959_c.jpg


Tape pulled and blobs cleaned up with a kabob stick. Like to pull the tape on these after about 5 minutes so the edges run flat.
 
Back
Top