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This site was created as a resource for anyone interested in hobby rocketry in central Indiana.

This is also the source for information on the Rocketeers Of Central Indiana (ROCI), Section #625 of The National Association of Rocketry (NAR). Feel free to check here for information about ROCIs launch events. The launch events are conducted throughout the warmer months at the Academy of Model Aeronautics' Headquarters and Aeromodeling Center in Muncie, Indiana. This facility is the finest flying field in the state and ROCI is proud to be the exclusive host of the rocketry events held there. ROCI is not currently conducting meetings as we have lost our meeting place.

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Winter Project - Spring/Summer Level 1 1 year 1 month ago #2687

Upcoming plans are for low and medium power and I will mostly stay there due to cost and ease of transport. This winter am going to try a home-designed Level 1 high power model as well as an inexpensive backup kit. Rather stunned at the amount of information out there. TMI? I think so!

For the kit, probably Apogee Zephyr or Aerotech Sumo - inexpensive and seem to be well-regarded. Recs?

For the homebuilt, am going to upscale a 1970's Estes kit. I understand the construction pretty well after spending some time reading instructions on how HP kits are assembled. Here are the questions!

Planning on using 75mm LOC high power cardboard for light weight and low cost. Build will be app. 61" long. TTW fins, plywood rings, flameproof cord, etc. Got all that. Avoiding phenolic, fiberglass, and carbon due to Hazmat for now.

Since the design I am up-scaling has swept-back fins, how do I keep the tips from being damaged? Light light weight, aircraft plywood, and adequate parachute are all on the list but I saw those asphalt landings at NARAM.

On fins, seems like most MFR's use 3/16" or 1/4" 5-ply. Would it be better to buy SIG 1/8" 5 ply aircraft plywood and laminate two sheets together for a very strong 10-ply fin? Their 1/8" 5 ply is awesome stuff. And would a layer of silk-span or other non-toxic covering assist in preventing tip damage? I had great results doing this on low power rockets and using dilute aliphatic resin instead of dope. Made them feel like plastic and didn't weigh much. Also understand that thicker fins are going to increase drag and thus aerodynamic stress on the rocket - something you didn't need to worry about with L + M power motors.

Will a hand-turned 76mm balsa cone stand up to Level 1? Very light weight if it will! I'll need to turn the nose to match the original kit.

29 or 38mm mount for level 1 and throw-away or reloadable?

The dreaded glue question - I KNOW that for joining cellulose - cellulose that aliphatic is super-strong. I also noted that epoxy is preferred for HP kits and for the engine mounting due to temp. Any suggestions? Is the epoxy just for quickness or is there a structural requirement?

Cheers / Robert
Cheers / Robert

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Winter Project - Spring/Summer Level 1 1 year 1 month ago #2692

Lots of ?’s! I’ll try to address some.
It was suggested to me to go with what you know and keep your cert flights easy. I realize that some will disagree with this and will want you to be “challenged”. However, my goal for my certs was to succeed first time, which I did. You can do more challenging things after you earn your certs, in my opinion.
Kits are just bucket of parts. Over the years I’ve modified most of mine anyway, primarily due to repairs. For my L1 I used my LOC/Precision EZI-65 kit. (I had flown it several times on G-80's). It had motor ejection of the main at apogee. (I’ve since modified it for dual deploy.) Now days, folks are using the Jolly Logic Chute release system.
For all my HP, except my L3 project, and much of my MP fleet, I use hobby epoxies for all of the parts, especially structural with good results. I have used JB Weld Steel for areas around the motor mounts since it has one of the best heat tolerances for epoxies.
If you beef up the fins, you want to check the CG. I use RockSim for my simulations. Although lots of folks are using OpenRocket. RockSim helps me choose an appropriate motor for my rocket. I like to go low and slow to be able to visually follow the rocket. So I look at the speed it leaves the rail (or rod) to make sure it’s high enough to be safe. And I don’t want to go supersonic as that requires more construction techniques, so I look at that. I like to be able to follow the rocket so I look at altitude. I was thinking of using my EZI-65 for my L2, but the smallest J put it up about 5000 ft. I didn’t think I could see that the entire way so I went with a larger PML Black Brant X kit with piston ejection. Again, I overbuilt the rocket and kept it “draggy” so I could follow it, again with motor ejection at apogee.
Balsa NC should be OK, but do check the CG. Depending on your fins and now NC, you may have to add nose weight and/or length to get a safe CG to CP.
While I’ve accumulated a number of reload casings over the years, I now fly mostly Aerotech DMS motors for HP. They’re about the same cost as the reloads (minus the casings.) If you go with reloads, think about what size motors you’ll be flying most of time.
I, too, have had some damaged fins on the pavement here. I would recommend a larger chute. Yes, I could have done that, but I didn’t want to risk going into the corn…so it was a tradeoff.
Good Luck.
Allan Howard
The following user(s) said Thank You: Robert Bantly

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Winter Project - Spring/Summer Level 1 1 year 4 weeks ago #2693

All good thanks! Will probably roll my own and follow this and kit builds.
Cheers / Robert
Cheers / Robert

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Winter Project - Spring/Summer Level 1 1 year 1 week ago #2714

Made some decisions - ordered balsa from Sig for the nose cone. Will have to glue (4) 2" x 2" blocks together and install a hard wood dowel for a solid turning and anchor spot if no payload section is used. Also ordered two sheets of 3/32" 5-ply aircraft plywood and silk span. Plywood will be laminated into a 3/16" sheet for fin stock. Fins will be covered in the silk span for improved strength. In past times, I wrapped silk span around the fin leading edge "sometimes" with great results - have to ensure 100% bond or you get a crappy flappy edge. May just do sheets on this project.

I went down from 1/4" plywood due to the covering and it's probably a little over-kill with TTW construction. Thinner fin = less drag and less shred force too, if I am reading correctly. Need to score some LOC precision 75mm tubes - Apogee is out so I will have to do some surfing.
BTW: Level 1 build will be an upscale of Estes 1271 - Renegade, 1975 version. Currently building a 1:1 bash from a Mean Machine kit I hope to have at CIRFF. On both models, getting a PNC-60AH is the hard part. One is by bash, and the other is by lathe. No one makes this cone in larger sizes. Sad since it is on Red Max also, another popular Level 1 build.

Still "way" underweight on paper on the level one. Means a solid paint job and probably payload section, and maybe some weight at the end too.

Cheers / Robert
Cheers / Robert

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Winter Project - Spring/Summer Level 1 10 months 1 week ago #2779

Anyone have any suggestions for cold weather use of materials with solvent/VOC's? My shop is heated but ventilation is REQUIRED. Don't want to breathe it or have any flammable issues in the shop. It doesn't take much solvent to reach flammable in an enclosed space. Epoxy isn't that bad on solvent but requires close temperature controls. I have thought about building a ventilated paint booth out of 4 mil plastic sheeting - anyone done this? I've seen a few on the web. Probably still some hazard there due to static in the dry winter airflow through the exhaust...
I have been kicking around HP fin coatings and looked at fiberglass and a couple other materials. Don't want to mess with vacuum bags. Since I know how to do it, may go with medium (GM) silkspan from SIG. You can get pretty durable with this stuff over a solid base and the "dope" (AKA clear lacquer) is more forgiving of environmental conditions, easier to work with, and way cheaper. Just takes longer to dry if in the 50s. You can also (if careful) wrap it or layer a strip over leading and trailing edges which should help prevent shred. Am not going to use water to shrink the span, over plywood it isn't required and would probably warp.
Was hoping for another warm winter but that isn't looking good.

Cheers / Robert
Cheers / Robert

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Winter Project - Spring/Summer Level 1 9 months 3 weeks ago #2790

LOC Mini-Magg and Estes Renegade upscale progress...links to my google drive.

The Magg has fins installed. I looked at this kit and decided no bevels - just gentle, sturdy rounds. It isn't very aerodynamic, it is heavy, and thus should give great take-offs. I don't think bevels would add much altitude. Fins are lacquered and coated with paper and GM silk-span. This worked and added quite a bit of strength but was highly painful. I will give the 6oz glass a try on the next set of wooden fins.
I used Apogee Rocket-Poxy and 600 degree JB Weld for structure and 5 minute Devcon with tape to pour the fillets. Fillets stressful but turned out way better than expected. Darrell is right, sanding epoxy is slow work. I top-coated the fillets with Bondo #2 Glazing putty and sanded down - couple passes required. No fill & finish - assumed Bondo glaze would stick to epoxy better than a wood product.
Started priming last night. Since I did a Giant Leap Sleeve and epoxy on the tube, there is a bit of "texture" that needs to be filled. Due to rattle can cost, I am using brush-on primer to fill the sleeve texture on the body tube. Quicker fill, more paint per pass with more mess to wet sand. Way cheaper than high build spray cans. When I get it reasonable, will break out the rattle can primer. Fins won't need much. A sim is required and it will need some nose weight at the end. Will expanding foam assist in holding the nose weight in place along with glue? Easy to do. Wanted it to be able to possibly take the J320 "someday" without shred/collapse and I think it's sturdy enough now. The epoxied airframe is super-strong but adds finishing work. May be due to me not coating it enough.

The lower section of the Renegade upscale is built - like the Magg, I used Apogee Rocket-Poxy and 600 degree JB Weld throughout. All that's left is to finish up the fins and turn the nose cone. I started the turn vertical on my Jet drill press (good suggestion Mario) and the chuck is so good that it started to cut into the dowel. Never burnt by a good tool before :lol: Working on lathe access to turn the upscale 60AH. Using the Jet requires an aluminum rod epoxied into the balsa!!! (Which is doable!)
The top coupler is an ejection baffle with #3 coarse steel wool loosely packed - no resistance to flow and it should stop all the sparks. Added some weight but this model is a ballet dancer compared to the Magg. It will go together a lot like the original - upper and lower halves separate till the end for painting. Hoping to keep weight under 32 oz built but will see - epoxy is heavy. Don't think nose weight will be required - 62" long built.

On adhesive: Devcon 5 minute worked great for fillets but you have to QUICKLY remove the tape :silly:
Apogee Rocket-Poxy is awesomely strong but the texture is similar to cold honey - you have to keep it level. It will crawl. Can't glue all your interior fillets w/o a mess. One at a time. It also spiderwebs - watch for that.
JB Weld Pro 600 degree was the easiest and friendliest to mix and use. Strong, great for motor tube and attaching parts but will NOT settle. Doesn't crawl/drip.

Cheers from my now slightly toxic shop! - Robert
Cheers / Robert

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