CF Optima MAC Performance ( Fins on!)

[DavidMcCann]

I can never wait until I have these things in hand to start a thread... here we go.

It's been a long summer, life is crazy. The wife suggested I get a new kit to build and relax a bit. I've got a good number of bases covered with what I have. Not really anything out there I'm just dying to have. I built the 54/38 zodiac last winter....finishing up my 4" Wildman now...

I've been considering a few things...I like small rockets lately. And flying more EX, means right now, more mid sized 38mm motors. And I like going fast. and relatively high. And I want something sturdy.

So obviously this means another Optima.

There are many aspects of this hobby that are enjoyable. There are times I love getting a pile of parts, cutting them out as I see fit and building a rocket as I go. There are time I like ordering a kit and modifying it to what I want. For this, I just want all the parts I want, no extras, all from the same place, one call, everything comes in a box, and I just glue it together and go and not be tracking down bits and pieces. Just looking for a nice relaxing build, easy to fly, manageable size. Herm. Time to call MAC.

So I emailed Mike, and tell him:
"I wanna do a downscale to 54mm, 38mm mmt"
"OK, no problem, send me the .ork"
We discuss some sizes and details and such, which parts I'm looking for where, what things he can do, etc. Then I remember to add-

"Oh hey....make it out of carbon fiber"

 

[rfjustin]

Purdy parts!

 

[Bat-mite]

Sheesh! Don't kill anybody with that thing. :wink:

 

[Tim51]

Looks more DARPA than Optima.. very cool.

 

[DavidMcCann]

My kit has traveled to me now. It's quite late, but I had to take a peek at it and snap a couple quick photos. The tubing has a snakeskin quality to it. Totally smooth, but the light reflects in an interesting manner on the matte surface. Once clear coated Im sure that will change, however it's pretty cool right now. There is no inconsistency in the surface, just how the light is reflecting from various angles.

 

[Barkley]

My kit has traveled to me now. It's quite late, but I had to take a peek at it and snap a couple quick photos. The tubing has a snakeskin quality to it. Totally smooth, but the light reflects in an interesting manner on the matte surface. Once clear coated Im sure that will change, however it's pretty cool right now. There is no inconsistency in the surface, just how the light is reflecting from various angles.

That's the joy of 2x2 twill on a rounded surface.

 

[DavidMcCann]

That's the joy of 2x2 twill on a rounded surface.

I should also mention it feels like it should be invisible.

 

[rfjustin]

Dual deploy out of nose cone? HED?

 

[DavidMcCann]

Dual deploy out of nose cone? HED?

current plan is an Xtra in the nose, and a JLCR. I'm not sure how hard you can push a CR, but that's the plan for now. If that won't do it, I do have a cutter laying around here someplace.

 

[rfjustin]

current plan is an Xtra in the nose, and a JLCR. I'm not sure how hard you can push a CR, but that's the plan for now. If that won't do it, I do have a cutter laying around here someplace.

JLCR should be just fine, if not all you need is a switch band. Just food for thought...

 

[DavidMcCann]

Popped open the kit and took a closer look at stuff. Nice, super thick canvas CR's. The top one has two notches for the kevlar, and two roll pins to slide in the loops. Very slick. (totally thought mike took "clone an optima" too seriously and cut a notch for an Estes motor hook at first ) Also some Kevlar cords, charge wells, and a sled with battery holder. The MMT is a nice red FG.

 

[mpitfield]

Very nice Dave, I am looking forward to seeing that one leave the pad.

 

[DavidMcCann]

Finally got a chance to sit down and weigh parts. Now to plug them into the sim and adjust.

3.6oz Nosecone
5.6oz NC Coupler/avbay/sled
2.13oz kevlar cords
12.65oz Body Tube
1.15oz Fin set 1
4oz Fin set 2
4oz MMT and rings
2oz 3' Chute
.66oz Charge canons


35.79oz dry, less electronics. This should zip.

 

[FMarvinS]

Looks great Dave. Please post your excellent photos of this bird at take off & in flight. Your rocketry photos are exceptional What motor(s) are you contemplating & are you going to use a CTI 6XL casing?

Regards,
Fred, L2
ICBM, Camden, SC
KG4YGP

 

[DavidMcCann]

Looks great Dave. Please post your excellent photos of this bird at take off & in flight. Your rocketry photos are exceptional What motor(s) are you contemplating & are you going to use a CTI 6XL casing?

Thank you, I hope I can grab more than smoke when this one takes off.

I'm thinking a few smaller motors to shake out using the JLCR, Loki 120's and some 2 grain EX. Then, I've got a Loki 38/1200 case I'd love to throw in it. Sims are coming out around 10,000' and Mach 1.5 with both the J1026 and K1127.

After that, if I can get EX sorted out a steady diet of 38mm 6 grains should be fun times. Earlier this year I had one take my 6 pound 4" Emerald Dragon to 2700'. If I can smooth it out, I think it'd make a nice motor for this rocket.

 

[REK]

Thank you, I hope I can grab more than smoke when this one takes off.

I'm thinking a few smaller motors to shake out using the JLCR, Loki 120's and some 2 grain EX. Then, I've got a Loki 38/1200 case I'd love to throw in it. Sims are coming out around 10,000' and Mach 1.5 with both the J1026 and K1127.

After that, if I can get EX sorted out a steady diet of 38mm 6 grains should be fun times. Earlier this year I had one take my 6 pound 4" Emerald Dragon to 2700'. If I can smooth it out, I think it'd make a nice motor for this rocket.

Holy cow thats a voilent take off, was that one of your OP motors?


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[DavidMcCann]

Holy cow thats a voilent take off, was that one of your OP motors?


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it was. The short version is that it held, nothing was damaged, but I'm not happy with it and doing some things to make it better.

 

[REK]

How is this build coming along?


Composite Addict

 

[DavidMcCann]

How is this build coming along?

Four ball joints, two hubs, speed sensors, sway bar links, rotors, caliper mounts, tie rod ends later, just need an alignment new tires an exhaust and a little welding and we'll be back on schedule

 

[REK]

Four ball joints, two hubs, speed sensors, sway bar links, rotors, caliper mounts, tie rod ends later, just need an alignment new tires an exhaust and a little welding and we'll be back on schedule

Man the struggle is the same on my end. Looking forward to seeing this rocket completed.


Composite Addict

 

[DavidMcCann]

OK.... back from craziness and vacation. time to get back to this.

Aeropack, JB weld, smush...

Normally I'll leave a thick bead, or fillet on the aero pack. For this one, I wanted it clean. Used as little as possible and wiped down the inside and outside

 

[DavidMcCann]

The harness on this one is mounted through the top CR, and held in place with two roll pins, one on either side. The ends are sewn and wrapped, as is the midpoint. The benefit of this setup is that, in the unlikely event one side snaps, the other side will get the rocket back in one piece.


dry fit at the top of MMT before glue

a very small bead of glue placed around the bottom of the CR

I then pushed the CR down just a nudge, making a nice, tiny fillet around the ring

inverted and set down to cure.

The next step will be to space the mid ring to sit on top of the lower fins, and to fillet the top of the mid ring, and the top ring.

 

[DavidMcCann]

Bulldozing along on this one....nice and slow.

A fillet was applied to the top of the top CR, not touching the kevlar.

Mid ring-

 

[Tim51]

Good stuff. MMT and install is always my favourite part of any build...not sure why - I suppose it's cos that's where the fire happens..

 

[REK]

Good stuff. MMT and install is always my favourite part of any build...not sure why - I suppose it's cos that's where the fire happens..

Agreed here, coming along real nice.


Composite Addict

 

[DavidMcCann]

Did a couple more CR fillets tonight. Phone died so no photos. Watching all the BF deals going out, this rocket is saving me hundreds by killing any desire to buy anything else lol.

 

[EXPjawa]

You know, Dave, it seems pretty funny that a dead phone has kept you from taking pictures...

 

[DavidMcCann]

You know, Dave, it seems pretty funny that a dead phone has kept you from taking pictures...

Lol. Point. But the camera was two floors up and I’m lazy.

 

[DavidMcCann]

OK, took the photos of the missed CR fillets

Also tonight, I added a bit to the top of the Bottom CR. First I marked fin locations, then added epoxy in 3 spots, leaving the fin locations open. I probably didn't need to do this, gluing the fins in place would likely be more than enough to hold everything in place... But I sleep better now.

 

[Barkley]

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.