Scratch Build: Up-scaled Stand-off scale of a Fantasy Scale...yep, the NIKE-X

I have a wish list/cart built at Apogee to scratch build an up-scaled Nike-X.

#12023 - (1) Motor Mount Kit 29/BT80 - Plywood Rings
#11013 - (2) 2.56in LOC Body Tube
#13160 - (1) 2.56" LOC Coupler
#20080 - (1) PNC-66A (BT-80) 3:1 Ogive nose cone
#29094 - (1) 30" Printed Nylon Parachute
#30326 - (10ft) Kevlar Cord 300# (minimum order length)
#30328 - (10ft) 1/8" Diameter Heavy-Duty Elastic Shock Cord (minimum order length)
#14510 - (1) 220# Ball Bearing Swivel
#13565 - (1pkg) Conformal Rail Guides for 2.6"/66mm Tube
#24020 - (1 pkg) 29mm Estes Motor Retainer

Need to get a small screw-eye/nuts/washers for anchoring to the top centering ring...I'll get it at Lowe's.

I'm thinking 3/8" balsa fins, but was curious about going with a slotted tube and tabbed fins glued to the motor mount and body tube.

Will butt joints (fin root directly to the BT) suffice, or should I get a slotted BT and tab the fins?

Semroc has a 4 fin pre-slotted tube (@ eRockets), or I could just go with a non slotted and butt glue.

Thoughts?

Upscaled Nike-Xes have been built and they are cool. Go for it.

Think it'll be okay to surface mount the fins?

I read through some threads in the "Techniques" sub-forum and only saw one thread about surface mounting fins, and he was going for his L1. I think the consensus was surface mounting them was okay (ply fins on Blue Tube) but advised to do some fiber glassing.

Jon

JonathanOtt said:

Will butt joints (fin root directly to the BT) suffice, or should I get a slotted BT and tab the fins?
Semroc has a 4 fin pre-slotted tube (@ eRockets), or I could just go with a non slotted and butt glue.

Click to expand...

I just build something similar :

I went with a 38MMT, as I'm going to fly it on Loki 38-120s. I put a baffle in the middle coupler and glued it to the top tube, the bottom is secured with a removable rivet which'll make it easier to transport. I put an eyebolt in the top of the baffle.

The bottom fins are TTW as they'll take the most abuse. I cut the slots myself with an exacto knife which was pretty easy. The smaller fins are butt joints. All fins are 1/8 ply.

I plan on flying mine with a chute release which fits very easily in the 2.6" tube with a 24" chute. First flight(s) should be this weekend at NSL.

cheers - mark

JonathanOtt said:

Think it'll be okay to surface mount the fins?

I read through some threads in the "Techniques" sub-forum and only saw one thread about surface mounting fins, and he was going for his L1. I think the consensus was surface mounting them was okay (ply fins on Blue Tube) but advised to do some fiber glassing.

Jon

Click to expand...

Fin slots are pretty easy to cut, especially on LOC tube that won't bend too much, and then you definitely don't need fiberglass. Just use aluminum angle and an Xacto knife.

The little canard fins should be OK to surface mount, but I'd go thru-the-wall for the big ones.

Apogee tends to run a bit pricey compared to other vendors. Also, I'd avoid mixing Apogee nose cones with HPR style tubes- they really don't fit.

Just my :2:

Thinking about going 3" on it now. Rocketarium.com has everything I need, and I think it's actually running a little less expensive. They have a 36" 3" diameter tube and a 13" exposed area 5:1 ogive nosecone. That'll put me at 49" and the larger tube looks a little better than the thinner tube. I do wish they had weights listed, but I think this will come in around the 14oz mark (based on weights calculated from Apogee's weights).

One quick question- why the baffle in the 29mm tube? If you have a baffle I'd put it in the main BT, just in case you want to fly longer motors.

I'm guessing it's going to come out a lot heavier tha 14oz- Apogee tubes are very thin, LOC tubes & nose cones are a better estimate. I think the 36-inch chute is overkill though. A 24-inch will likely do jut fine- my 2 lb, 3" Pro Series II kitbash AMRAAM uses a 24" chute with no issues.

If you're going with a baffle, I'd lean toward elastic shock cord. I'd prefer the added stretch to the slightly higher strength of Kevlar- especially in that small size Kevlar can be very zippery.

What's your motor of choice? Light 3" rockets on G64s (G68 if you're a CTI person like me) make great majestic flights...

OK, that was a lot more than one quick question.

I know my weight estimates are probably off. I based them off the weights listed on individual items from Apogee, and it is without the motor weight, adhesives, paint and decals... It'll most likely be upwards of 2lb. all said and done...wet, on the rail.

I'm going to purchase a basket full of Estes Pro Series II F & G motors from my local Hobby Lobby that has them on clearance for like 75% off...G40-7W ($6.99); F26-6FJ ($6.25); G80-7T ($6.99); F50-6T ($6.25)...they have two of each.

I based my tube weight estimates off the LOC tubes from Apogee, and with a 2.56 x 30", add an 8"section and a coupler, I'm getting 8.143oz...where the 3" x 34" LOC is 7.91oz. The Rocketarium 3" is 36" long and should be under 8.143, even with the extra girth (and the extra girth makes my sketched model look a little better...plus, the girls like girth over length, right? :rofl:

I wish I knew the weight of the nosecone I selected, but Apogee has a comparable at 4.83 oz.

Good idea on the shock cord. it'll save me a few $$$ too.

I had a 30" chute in mind initially, but I'm not opposed to coming down to a 24". More $$$ saved!

The tube baffle is what Rocketarium has, they don't have a 3" Main BT baffle listed. Also, by motor tube is 11" ain't that long enough for all the 29mm's out there? I doubt I'll ever fly it once I'm through the eight motors I'm buying. I'm active duty Army and getting stationed close to a suitable field for 29mm motors is gonna be tough.

I'm still shopping, figuring things out and such. Once I get it all together, final list, I'll publish it.

Thanks for your help!

Jon

Putting this on the back burner. Ended up ordering $175 worth of kits ans stuff from AC Supply!