LUNAR'clips

Volume 6, Number 5 -- September/October, 1999

Newsletter of the Livermore Unit of the
National Association of Rocketry

In this issue:

Note from the Editor

by Tom Hail, LUNAR #440

Welcome to the NARAM-41 Honorably Mentioned LUNAR'clips newsletter.  We didn't win the Rockwell trophy for best club newsletter, but we should be well pleased by the recognition.  The physical effort to produce this newsletter is second to the articles written by our membership.  The diversity and quality of them is what the recognition is for.  We should all give thanks to those who wrote articles in the last year and to those who will in the coming years.

LUNAR Meeting September 8

7:30 p.m. - 9:30 p.m.  (Wednesday instead of Thursday)

Carnegie Building in Carnegie Park between 3rd & 4th Streets in Livermore.  Mark Jegher may discuss mach busting or altimeters or Jack will show his NARAM-41 slides, either in addition to the usual club business.  But this may be old news considering this newsletter won't hit the street until the day before!

Next LUNAR Launch September 12

8:30 a.m. - 12:30 p.m.  (Yes, a Sunday on the 2^nd weekend of the month) at Robertson Park.

This is a regular sport launch.  Maybe the wind will be manageable this month unlike in August.  If its light, I'll try to screw up my courage to fly my Saturn V again.

The Range Head, May 1999

Jack Hagerty, #002

SCHEDULE CHANGES!

This may reach you too late for the September launch, but just in case, I'll mention it anyway. You should all mark your calendars NOW! It seems that a lot of you were caught off guard by the August launch being a week early. Remember that the "third Saturday" launch dates are just a goal, and that we have to bend to the will of LARPD scheduling since they let us use the field for about 1/6 of the price they charge others ($50 instead of $300).  Note that the September date is not only a week early, but on a Sunday as well. Note further that the Meeting is on the Wednesday before the launch (Sept 8), not Thursday. Both the August and September dates have been set since last April when I re-negotiated our schedule with LARPD.

For October we have a real change. I got a very polite phone call in early August (before I left for Pittsburgh) from LARPD. They have an event that wants to use "our" field on October 16 that is willing to pay full price. As per our agreement, they have the right to bump us with as little as two weeks notice, and they actually gave us two months. This is just a little change, only one day, but it seems like I better start letting you know now. We're moving it from Saturday 10/16 to Sunday, 10/17. Remember that this is the night launch.

SPEAKING OF THE MEETING

According to the schedule, the presentation at the September meeting is supposed to be Mark Jegher's talk on altimeters and such, but at my deadline for this column, I wasn't able to confirm that he'd make it. If he can't, I'll just bring my slides of NARAM 41. You can't say you haven't been warned!

KUDOS ALL AROUND

Great job at the Apollo 11 Commemoration in July! We had a big crowd thanks to the newspaper coverage, and we did manage to impress the assembled multitudes, but not quite in the way originally intended. The number of prangs and recovery failures was distressing, but isn't that the way it always is with demos? At least we got huge cheers when the 'chutes did bloom successfully!  I got the report from Ron Baskett about the August launch. Sorry the weather didn't cooperate better, but at least we had the upper hand regarding the soccer game (i.e. we were there first). This happened last year as well.

NARAM NOTES

Elsewhere Tom has a short article on my trip to Pittsburgh for NARAM 41. I had intended to have a whole bunch of photos ready for the article, but it just didn't happen. We'll get them posted on the web site before long. 

Welcome Letter Response

By Ron Galien, LUNAR #796

Thanks for the welcoming letter! I joined LUNAR two months ago, built two AAMRAAM III rockets and certified for high power through your club. I am completely hooked on this sport and look forward to each and every launch. I wanted to commend you on your success with this club!! It is run very professionally and my family looks forward to it each and every month. I have 3 buddies who have joined LUNAR since then and we have more that want to join!!! Rocketry is my FAVORITE sport.the adrenaline rush from a high power launch is phenomenal!!!! Enough of my babbling.... WE LOVE LUNAR!!!!!!!!!!!!!

http://209.63.222.24:80/amCOOPER/lunar/welcome.html

Apollo 11 Celebration Launch Report

By Ryburn Ross, LUNAR #659

Ryburn and his baby. (JPEG 49KB)

Well, on July 17th, the space race of the 60's was revisited at the Lunar Model Rocketry Club in Livermore California. The event, coordinated and arranged by Bob Fortune, a space pioneer in his own right, involved the setup and launch of about 10 Saturn V's and other important landmark vehicles. The models, most of them the new Estes Saturn V's with plastic wraps, were first placed on a large rack that someone was kind enough to bring. At about 10:00, the festivities began with a large group picture of the Saturn's and their respective owners. I count myself lucky to have been standing within 100 feet of the rockets much less to be able to claim one of them as my own. After the picture, everyone proceeded to prepare his or her rocket for flight, meticulously checking and re-checking each step to insure a successful flight.

I walked out to my pad after preparing my Saturn V, feeling the 13 ounce monstrosity sag in my arms. As I walked past one group of boy scouts I heard a young rocket scientist say with astonishment "Wow... that rocket looks really cool..." I smiled grimly to myself, wondering, would it still look "cool" after its first flight?

The wind calmed and the grass quietly rustled, as all eyes were glued to the concoctions of paper and plastic sitting one pads 1-10, anticipating, eagerly awaiting the launch, much as the crowds at Kennedy must have waited 30 years ago.

The LCO, Bob Fortune, cleared his throat, knowing full well the honor he had bestowed upon himself, for he would, although not launching a rocket himself, play a key role in the voyage of each and every one. With a calmness none of we builders could feel, he slowly began the announcement. "We are now ready to start launching the Saturn V's." The only sound to be heard was the slight cackling of the loudspeaker, as all seemed to hold their breath and anticipate the countdown. With an almost casual tone the LCO began... "5.... 4.... 3.... 2.... 1.... Launch!" And... nothing. Failed igniter. "The igniter failed" the LCO announced. "Pad 2, going in 5.... 4.... 3.... 2.... 1.... Launch." A puff could be heard over the dead silence of the midafternoon as the Crapperhead igniter in the E15-4W of the motor "chuffed." Groans of frustration could be heard over the cackle of the loudspeaker. The LCO, unwilling to lose the crowd, quickly said, "We'll go on to pad 3, 5.... 4.... 3.... 2.... 1.... Launch!" This time the motor answered our beckon as the heavy craft struggled off the ground. The Saturn V flying on a D12-3 slowly forced its way into the now seemingly thick air, struggling against the pull of the earth, on its way skyward, and then, no......(!), the model began to arc over at about 50 feet up, seeming to go unstable. The dead silence of the launch was broken by the murmured worrying of the crowd as key phrases graced the air. "Oh no!, its 'cruise missililng.'" "Watch out." "It's coming this way." And the final cry of "HEADS UP!" as the mighty ship crashed into the ground on its side, smoke continuing to pour out the rear, and now, only a little to late, pouring out the front as well.

After this flight, and two more igniter failures, the rack that my rocket rested on came up.  Pad 7 was up first. On pad 7 rested a beautifully finished Saturn V, not unlike my own, sitting on a F12 Blackjack motor, ready and willing to leave the earth. There would be no delays this time.

The LCO, again clearing his throat, started into the standard routine "On pad 7 we have another Saturn, this one flying on an F12." "It's going up in 5… 4... 3… 2… 1… Launch." With black smoke pouring from its tail, the model rose slowly into the air slightly wobbling. At about 200' the model began thrashing as if it had seemingly, like the first Saturn, gone unstable. The model quickly turned to its side and descended to the ground to a rough landing against the still wet grass.

I had begun to perspire lightly now... 4 igniter failures and 2 crashes. No successes! But there was hope yet, for before my model would fly, a primer coated Saturn V sat menacingly on its pad, looking, for all its nakedness, ready and willing to send the first men to the moon. It appeared as if in a rush to beat the Russians to the moon NASA had decided to put all its painters to work helping to construct the huge rocket, and had, in the process, abandoned all hope of allowing them to arrive on the moon in style.

The crowd was less tense this time. Even if this model did crash, it was unpainted, and looked less vulnerable for it. "Another Saturn V on pad 8" the LCO said with the envy clear in his voice. "We're going to send this one up in 5.... 4.... 3.... 2.... 1.... Launch!" The rocket slowly ascended with a white pillar of smoke chasing it into the heavens, rising to 100, 200, 300, and possibly even 400' on its E15-4, and then slowly turning to point towards the ground again, and just as everyone began to hold their breath again... the upper section shot off the base tube and 3 nylon chutes spread their canopies. A success!!, a total success!!! The cheer, starting loudly and slowly diminishing in volume, congratulated the builder on a perfect flight.

Now, of the Saturn V's, only mine remained. The crowd once again centered its attention on the pads to gaze at my rocket, my freshly painted, perfectly clean, nearly perfect rocket. With a pang of anxiety I looked at the meticulously masked and painted sections, the troublesome decals, and everything else from the fairings on the bottom to the small fragile tower on the top. Should I call off the launch???? Did I really want to do this???

Almost as an answer to my question, the LCO began his spiel. "And on Pad 9 we have another Saturn V". "We're going to send 'em up in 5.... 4.... 3.... 2.... 1.... Launch!" And as an answer to his demand the motor sputtered, then leapt to life, a white flame flickering from beneath the silver fairings as the heavy, bulky, draggy, and extremely beautiful rocket slowly took to the air. My heart sunk to my knees as I gazed up while the rocket slowly burned its way into the blue void above. The realization hit me like a brick to the face: it was really working!!!! That was my rocket slowly spinning towards the moon millions of miles distant. "Yes!" I heard a voice shout. Had that been me? My mind was racing as my feet were slowly moving, my hand to my head, blocking the sun, as I gazed upwards to the sky above, knowing that above the deep blue of day reside the bright stars of night and the moon along with them. I now heard the voice again, still disconnected, as the model slowly turned over at about 400', this time pleading... "Please a 'chute, I need a chute." Had that been me again? As if in answer to the desperate voice a load bang shattered the quite of day as the forward section of the model shot forward and bright plastic canopies filled the sky above. Both sections of the model were drifting slowly down under full canopy, to a landing a mere 50 yards away. Letting out a pent up breath I hadn't realized I'd been holding I considered whether I should jump for joy or scream, deciding instead to simply sprint to my Saturn V.   Upon reaching it I looked the entire model over. All the decals were still attached and there were no breaks, scratches, bends, or crimps anywhere on the model. A simple satisfied "perfect" escaped my lips as I basked in the knowledge that my Saturn V, my pride and joy, was perfectly okay. As I drifted off into oblivion I heard the cheer of the crowd as they applauded the launch of yet another Saturn V, and I realized I was, perhaps, in a rocketeer's heaven.

High Power Certifications at Fresno

By Joseph A. Heckenbach, LUNAR #509

James Spurling preparing to launch. (JPEG 72KB)

Andrew Pohlman in the alfalfa. (JPEG 55KB)

Bill Townsend also in the alfalfa. (JPEG 58KB)

Judy Heckenbach after a great flight. (JPEG 86KB)

A few months ago I was asked by LUNAR club members Andrew Pohlman and James Spurling if I would be interested in helping to certify them and Bill Townsend to Level 2 High Power at an upcoming launch at the Tripoli Central California launch site at Fresno. Judy and I had not been to a Fresno launch but had wanted to go for some time. This sounded like a good reason to go so we said yes. Besides, Judy had made a rocket with which to certify Level 1 and was itching to try it out.

I made a quick check with the Tripoli guys at Fresno and they didn't mind as long as we brought our own certification team. An e-mail to Steve Lubliner at NAR with a few questions about the procedures for making all this happen got three certification tests on the way. The group decided on the August Fresno launch.

Andrew was to supply the necessary motor reload kits. Everyone had a suitable rocket either ready or almost ready. Andrew and James had Public Enemy Fat Boys as their rockets of choice. Andrews was the six-inch version and James' was a four-inch Ultra Fat Boy. Bill had a six-inch Bullpup. The mighty Aerotech J350 was going to power the rockets and would turn out to cause a "spot of bother" come launch day.

In the time preceding the launch, we kept in constant contact with each other. There was initially some confusion as to the date of the Fresno launch and when this was cleared up, there was some doubt whether or not the reload kits would get here in time, but this proved not to be a problem. The date was a problem though. Andrew needed to be at a wedding that same day and postponing it until the September launch was out because that fell on the same date as James anniversary. So it was decided that we would go with the August launch anyway. As it turned out, the Fresno launch was the day after our own August 14 launch in Livermore.

All of us except Bill came to the Livermore launch but I don't think we flew anything. Judy and I had talked earlier about going from Livermore straight on down to Fresno and staying in a motel since we were already a third of the way there and that's what we did. James and his wife had the same idea and followed suit. Andrew and Bill decided to tough it and made a very early Sunday morning drive down to the launch site. By the time Judy and I got there about five after eight, our Sunday drivers were there and in the process of unpacking. James rolled in just a bit later.

The first order of business was to get the written exams out of the way. Everyone breezed through and, to be honest, it took me longer to grade them than it took the guys to take them. Now it was time for some fun! The smoke and fire part. Reload kits were handed out and motor loading began. And so began that "spot of bother" mentioned earlier.

Bill got his missile ready to go first and quickly got it RSO'd and assigned a pad. He loaded it on the rod and just before launch time, decided to use a shorter delay having been convinced that a thirteen-pound rocket needs a short delay even for the mighty Aerotech J350. He scrubbed the launch and brought it back in. In the mean time Andrew was having fits trying to get the fuel grains into the phenolic liner. They were just too tight and he went through three reload kits to find some grains that he didn't have to destroy to get in the liner. I've never had that problem in any of the J350 kits I've used, so I didn't know what to tell him.

By this time, Bill had changed the delay and had his Bullpup back on the rod and ready for action. The countdown came and his rocket took off on a smoky pillar of fire. Right about apogee, the chute came out and the Bullpup came down to a gentle landing in the alfalfa. He retrieved it and brought it back for inspection. Everything looked perfect. One cert 2 down, two to go.

Andrew was next up having finally "coaxed" the stubborn fuel grains into the motor liner (beat into submission?) The Fat Boy went out to the same pad that Bill had successfully used. Hoping some of that good luck would rub off? No, it was the only pad with the correct size launch rod. "C'mon Andrew, ya aren't nervous, are ya? I wasn't nervous on my cert 2 flight." Yeah right. If someone tells you they weren't nervous on  their first cert flight of any level, they'll lie about other things too. I was on pins and needles on ALL of my cert flights. Finally, it's Andrew's turn. Countdown: five, four, three, two, one, fire! A split second passed then came the sweet music of that J350 roaring into the sky. Big chute at apogee. Rocket drifting gracefully down. Inspection reveals not a scratch on it. This is getting boring guys. You're making it look too easy. Two down, one to go. Next.

Ok, James, it's Showtime! The Ultra Fat Boy gets through the RSO and is assigned a pad. I follow with the video camera to get some closeups of James loading the rocket. "Houston, we've got a problem." The launch rod is too big and the thumbscrew holding it in is rusted too tight to turn with human fingers. I tell James to go ahead and install the igniter while I run back to the LCO table to get some pliers. By the time we got the rod changed, we were the last ones on the field so no video of the loading procedure. The LCO rapidly runs through the line of rockets and comes to James Fat Boy. "All right, James make it look good and don't blow that motor" I tell him. (That's my borrowed J350 motor in that rocket.) Countdown comes and right on cue, another Aerotech light show does its thing. This time, deployment is well past apogee. Both chutes are out and open then the nose cone plows through one of them tangling it. Good thing you had a backup chute James. He gets the rocket and we look it over. Looks good. Where's that form and we'll sign you off. All three Level 2's signed, sealed and delivered. Only one more cert. flight to go.

"Judy, where's your rocket. Show Andrew and James you know how to put a rocket together." Her rocket is one I designed for her using some concepts I wanted to try out. Advanced yet simple things like anti-zipper design, part tubular nylon, part kevlar strap shock cord epoxied to the rear coupler wall, missile works motor retainer, motor mount set up for a single use motor as large as an Aerotech H125 or their new reloadable 29mm I200, Rocketman chute and deployment bag and so on. I  basically made a kit for her by cutting everything to the proper size and let her assemble it. She did a very good job too. I also thought she did a good job of showing the guys how to pack a chute and load a motor. Then we were off to get it checked in and loaded on a launch pad. Her rocket looked great on the pad. A bright yellow and blue color scheme she got from Stearman PT17s that we'd seen at air shows. The LCO did the countdown and up it went on an Aerotech H124 fastjack single-use motor. I was taping the launch on video and lost it when it went in front of the sun so I didn't get to see the chute deployment. Andrew and James said the chute came out near apogee but didn't open for several seconds. I didn't get the rocket back in the camera 'til after the chute had opened. The chute probably had hung up in the deployment bag but eventually came out. Good thing for that anti-zipper design. Anyway, it was a successful flight with no damage and Judy was certified  Level 1. Now she wants me to design her a Level 2 rocket. Uh Oh, I think I've created a monster!

Our Fresno adventure was a great success. Mission accomplished. We did what we set out to do. Some may question why Level 2 when our field is restricted to only H motors. It isn't only to be able to use larger motors in bigger rockets at other fields, but to learn to build better and stronger rockets that can safely handle more horsepower. Rockets that don't shed fins or shred at Max-Q. Stronger rockets are safer rockets. How strong are yours?

Skinning Cats to Fillet Fins

By the members of LUNAR

The following was pulled from the LUNAR-general list in late July of this year.  The give and take of information is one of the reasons we have a club.

Steve Malin:  I am putting together my first G class rocket, and the kit calls for certain epoxy joints to be 'filleted'.  What does this mean?

Tony Cooper:  Filleted is filling the joint between two pieces (such as the body tube and fin) so it has a nice smooth curve to it.

Steve Malin:  Thanks for your response.  How exactly does one apply the epoxy?  I tried recently with a plastic stick (after mixing the epoxy) and it turned into a royal mess.  Is there an applicator or other device to apply epoxy in a bead?

Tony Cooper:  Ah! That is a good question. It will also start a debate. I have found no good way of applying the epoxy. It runs everywhere and is sticky. But in general, I attempt to put it where I want it with a piece of balsa. As gravity takes it toll, the epoxy also begins to harden. I use alcohol soaked rag to wipe the epoxy smooth and get it into the joint that I want. With 5 minute, timing is everything. You have about 20 second to work with it between getting firm and getting hard. I haven't tried working with 20 minute or longer stuff.

Steve Kendall:  Debate?  Nah.

If you mix some micro-balloons into the epoxy when you first mix it up, it will "stiffen" it up making it more like peanut butter.  It doesn't run as bad, is a little easier to sand, makes the fillet lighter, and is just as strong.  It also helps if you put little masking tape "dams" at the ends of each fin to be filleted, so that the mix can't run all over the body tube.

I use 20 minute epoxy for this, and once mixed with micro balloons, it sets up in about 12 minutes, plenty of time to play with it.  You can still use alcohol to smooth it once it sets.

Oh, and micro balloons can be had at any good hobby store pretty cheaply.

Jack Hagerty:  I use a technique that is very time consuming, but gives very good results.

First, I mount the rocket horizontally in a cradle of some sort (usually a cardboard box with notches cut in the side for the body tube to rest in). I rotate the body so that the blank area between two of the fins is upper most which means that there are two fins pointing diagonally upward with a valley between them and the BT. I mix up a small amount of epoxy (I use 20 min) and dab it along the root with a popsicle stick. I start in the center and work my way outward. Gravity forms the basic shape and you have to learn when to stop so that it doesn't run out the ends. After the epoxy has started to set, I run my finger (inside a latex glove) wetted with alcohol down the fillet to smooth it. After that I let it set overnight before disturbing the model. Obviously this technique can take several days, but you can shorten it up some if you trust the epoxy not to sag after a few hours.

Lee Teicheira:  I use the same technique that Jack describes. Works great. Takes about an hour to do a 3 fin rocket. Micro balloons, as Tony suggested, also works well and I highly recommend it. Only use polyester MBs, never glass. Not even sure if you can get glass MBs any more. But just as good and much easier to use is Goldberg Epoxy Plus, available from Sheldons, Bee Gee, and more. This is 16 minute (I think) epoxy pre-mixed with polyester micro balloons. It's lighter than regular epoxy, just as strong, and more flexible. (which is good, V2 tail cones survive vertical decents from 1500' when built with this stuff. Can't say much for the forward 2/3s though.) :( It's stiff enough to stay put and sands easily. I use it for most of my construction. (Also use thin and thick Hot Stuff, no white or yellow glues anymore) The mid-range (~15 minute) epoxies are probably the best for our use. 20 minute epoxy is typically "topping" epoxy intended for use as a sandable top coat on epoxy/glass lay-ups. 30 minute and longer epoxies although providing lots of working time and good adhesion, tend to be more brittle. 5 minute epoxies set too fast for good adhesion and also tends too be more brittle, though I do use 5 minute to build boat tails and transitions which I make from a double wrap of velum drafting paper (16-20 pound). When working with epoxy, always use skin protection, either gloves or skin treatment which is available from Tap Plastic or other suppliers of resin and fiberglass. Epoxy intolerance builds over time and doesn't go away. A good discussion on epoxy safety is presented by Dangerous Dave at http://www.ddave.com/safety.htm. Also lots of good info on composite construction in general. Dave can't get near epoxy anymore. He learned what he's talking about the hard way.

As far as epoxy tools go, craft stores like Michaels have hobby sticks (i.e. popsicle stick) by the box, cheep, like a couple of bucks for several hundred. enough to build rockets for a long time. That is unless your kids use up the white glue that you don't use anymore sticking them together to make houses and boxes...:) Half of a paper plate makes a good mixing surface. Cheep and disposable. Also go to your local Rocket Supply/Pharmacy for 99% rubbing alcohol. Don't use the 70% junk on the shelf. Too much water. Ask the pharmacist for the good stuff he keeps behind the counter. Don't use acetone, too dangerous. While you are there get some tongue depressors. They are just the right size for making fillets on 3 and 4-inch rockets. Use the round end to form the fillet. Rub alcohol on the fillet with your finger as the epoxy hardens to get a nice smooth finish. When fully cured, knock the gloss off the epoxy with fine sandpaper. Wax floats to the surface as epoxy cures causing the gloss. Paint doesn't stick well. Larger radiuses can be made with a strip of thin plywood (~1/16) cut to the desired width and radiuses on one end. You can probably find tongue depressors at the craft store also. Likely cheaper too. (I like cheaper...:)

Bob Fortune:  From my experiences, pretty much anything works as a thixotropic agent as long as it's dry and doesn't react with the epoxy.  Dryer lint, sand, talcum powder, etc.

The fillers I have used though are cab-o-sil, which is good for filling but makes things brittle; microballoons which Steve suggested in either glass, phenolic or if you want to get really fancy, carbon; milled fiberglass which adds a ton of strength but increases weight as well; chopped fiberglass which is 1/16" pieces of the stuff, and talc which fills but adds nothing for strength.

I start by mixing the epoxy 50-50 by volume with whatever I am using and go from there.  A nice peanut buttery (smooth type - not the chunky <g>) consistency is easiest to work with from my experience. If it looks too runny, add some more filler.  A popsicle stick describes a 3/8" radius in the fillet very well.

I smooth the stuff into the fillet like Jack said, making sure every part of the fin and BT that I want epoxy on has epoxy on it.  Then I form it with the calibrated popsicle stick, scrape off the excess, wipe the BT and fin clean of residual epoxy with denatured alcohol, and allow the epoxy to cook to a putty-like consistency.

Once its gets to that stage where it's still deformable by finger pressure I smooth the fillet with denatured or spit or windex or 409 or whatever is handy. I then clean off the fin and BT with denatured to make sure that there is no residual epoxy that I have to sand off later. Checking the fillet one more time for smoothness I let the thing cure up or heat it to about 150 deg if I'm in a hurry and move on to the next set of fillets.

No doubt there is a TAP plastics place in S. Cruz, they have all the goodies I mentioned above. Except for the dryer lint though. : )  Be prepared to spend some do-re-mi, they have lots of other cool things as well!  I think there is also a Systems 3 dealer in your town too that should have all this stuff if you want to go that route.  Hobby shops are pretty pricey for the quantities you get. At TAP, look for 314 Resin and 102 Fast Hardener. The 102 sets up in about an hour or so at room temperature, or about 10 minutes at 150 degrees (an oven on warm).

Joe Heckenbach:  Well, I guess I'll put my two cents in the great epoxy debate like everyone else. First off, for fillets use fifteen minute or longer epoxy so you'll have time to do something with it. The cooler the temperature, the longer the epoxy will take to set. In the middle of winter at 3am in the garage when the temp is 40 degrees, five minute is ok for some things (though I rarely use it for anything.) In the middle of summer (a normal summer that is) five minute is almost useless. It sets way too fast and you have almost no penetration. The fastest I now use is usually 12 min depending on what I want to stick together (or how big a hurry I'm in.) The longer the epoxy is formulated to set up, the stronger and more flexible it will be.

The biggest tip I can tell you is to use a heat gun like those used to apply the heat shrink covering on model airplanes. I almost never use any kind of epoxy without a heat gun. Why a heat gun? First, it thins the epoxy so you get better penetration, it flows much better. Second it sets it up much faster than just leaving to itself. Third, because the epoxy is thinner, the bubbles that naturally occur from mixing will come up to the surface and pop rather than being trapped in it. (The last time I looked in my engineering books air still didn't have much structural strength.) The only problem with using a heat gun is that it does take some finesse. You need to be extremely careful not to heat the epoxy more then 125 degrees or you will weaken it. It becomes very brittle at high temps while curing and after fully cured. If you need high temp epoxy the easiest source is JB Weld from your local auto parts store.  And also when using a heat gun, because the epoxy will thin so much it will tend to be very runny till it sets. It isn't difficult to do, it just takes some skill.

For fin filleting, I do pretty much what Jack does except I put strips of masking tape parallel with the fin and spaced out about 1/8th to 3/16 of an inch on the fin and on the airframe. Put the epoxy in the fin/airframe junction (how much is a matter of experience, but enough to have finished radius of about 1/4 inch.) Try to get an even amount from front to back. Take out your heat gun and give it a little heat but don't get so close as to start blowing the epoxy out. When it is getting close to STARTING to set, peel the masking tape off and let the epoxy flow just a bit on the fin and airframe. Obviously, you need to keep the airframe horizontal or it will run off one end. If you've done it right you'll have a strong and perfect fillet with no sanding or popsicle sticks or whatever. Let gravity do the hard part. It sounds a lot harder to do than it really is but once you get the hang of it you'll find it's the only way to do fillets.

I use this method for doing fillets on airframes from BT5 (13mm) up to 4 inch. On larger airframes, either a double application or a filler is needed. For the best strength use colloidal silica, cab-o-sil, or the milled fibers that Bob mentioned. If you want (need) lightness use microballoons (I use glass ones), talc or something like that.

If you want a good reference for anything you want to know about epoxy, go to Gougeon Brothers web site (they make West System epoxy) and order their user manual and product guide. The address is www.westsystem.com. I use their 205 and 209 epoxies depending on the temperature of my garage when I'm using it.

Hope I haven't bored (or worse confused) you too much. This is what works for me.

William "Chops" Westfield:  Replace the heat gun with a hair dryer, and you have a lot fewer worries about overheating the epoxy/rocket.

Frank Demcak:  I agree with all the great postings especially Jack Haggerty's suggestions on the horizontal fillet technique (which I use).

One comment on micro-balloons or other colloidal fillers, use them sparingly. I would test the type of epoxy you're going to use (i.e. 30, 60 or 1hr epoxy) with various amounts of filler, let it set and test it for strength.  You'll find the more filler the more soft and less strength you'll have in the epoxy joint.

Roger L. Deran:  This is great. I have learned so much from this thread on epoxy:

How to eliminate bubbles;

How to cure faster with heat, also to increase adherence;

How to smooth and remove excess with Alcohol;

Where to get microballoons;

Types of microballoons;

etc.

Also, I believe after about a year of use, my epoxy has gone bad. The joints seem to be brittle. I got some new stuff and it is thinner and wets the surface better, and seems to give better joints. I don't believe the original epoxy had gone bad when the EZI-65 was built, though. Does epoxy really go bad like this?

John Coker:  I've never heard of epoxy going bad once it's been applied.  My best guess is an incorrect ratio or insufficient mixing.  I've been told "you can't over-stir epoxy."  It is possible that epoxy might change its texture due to heat.  The fin roots are subject to the heat from the motor case, but it should never get *that* hot.

Brett Buck:  I think that a better way to go may be to use either SIG Epoxolite, or Aeropoxy Light fillet material. I've used every kind of filler/gelling agents in regular glue and it just doesn't work all that well, and as everyone has found, it tends to want to run everywhere. I think maybe just biting the bullet and getting the lifetime supply of Aeropoxy Light from Aircraft Spruce and Supply will save you a bunch of hassle in the long run.

Bob Fortune:  There are so many ways to skin a cat when building rockets  ... probably accounts for the lack o' cats at launches.

There is no such thing as a dumb question like you say, I try and ask them all the time and end up learning at least a couple of new things at every launch.  That's what makes this avocation/pastime so dang interesting I think.  The patience and willingness to share by all the participants.

I'd like to see more threads like this last epoxy one on this list.  There is a lot of talent represented here with a variety of viewpoints, methods, and madnesses. Makes it fun!

NARAM NOTES

By Jack Hagerty, #002

A shot of Jack and his "Cubs in Space" T-shirt given to him by the SF Bay Area Council after presenting a talk to 150 cubs at a recent camp. (JPEG 44KB)
(photo taken by George Rachor)

A shot of Bill Dauphin (on right) and Mark Bundick discussing how the strap-on boosters of Bill's Delta III model are attached, but it looks like they're trying to put the hex on each other! (JPEG 46KB)
(photo taken by Jack Hagerty)

I had an enjoyable, if somewhat tiring, time in Pittsburgh representing LUNAR at NARAM 41. It was tiring since it was on East Coast time and a lot of the  meetings ran to midnight or later (which made the 7 AM alarm come really early!), but it was all very worthwhile. The weather was a very strange mix of hot and cold, humid and dry, rainy and sunny; all in one week!

The section advisors' meeting (one of the ones that ran past midnight) had a troubling message from NAR President Mark Bundick. Even though NAR membership is up substantially the past few years, the gains have all been  in the adult membership category, while the "Leader" category (ages 14 through  17) has been shrinking significantly. The "Junior" category (13 and below)  has been shrinking too, but not as dramatically. The reason this is a concern is that the surge in adult members comes largely from the "BAR's" (Born Again  Rocketeers); people who enjoyed rocketry as a kid, and then rediscover it as  an adult (like me, for example). If the NAR can't attract kids into the hobby in the first place, then there won't be any source for future BAR's. 

I was able to share with the assembled club leaders LUNAR's outreach programs with the local schools, scout groups, 4-H and other civic and fraternal organizations. This is very impressive to the national as many local clubs are having the same membership problems and admit to being very envious of our 15-and-under membership numbers. Of course, LUNAR's large junior and youth membership doesn't necessarily translate into memberships in the NAR, which is considerably more expensive, but Mark will be unveiling some plans  along those lines over the next year. I'll keep you informed as we go, but  for now Mark is trying to assemble a list of educators and youth program  leaders who use rocketry in their classes and activities. This list will  be used to let them know of new programs and support from the national  organization to help in their classes.

A shot of Jack taken at the "Manufacturers' Forum" while pushing my book. (JPEG 53KB)
(photo taken by Doug Pratt)

Another shot of Jack and Bill Spadaforda (the head of NARTS). (JPEG 44KB)
(photo taken by Doug Pratt)

Since we don't participate in competition in any meaningful way, I didn't really expect to hear LUNAR's name at the awards banquet, but there are two areas where we do compete: the Rockwell trophy for the best club  newsletter and the "Section of the Year." They don't read all of the participants in these two events, but rather just read two "Honorable Mentions" and the winner. I though we had a shot at the Rockwell and sure enough, when they read the HM's the first one was "The LUNAR 'Clips, Tom Hail editor." Congratulations, Tom! and to Lynn too since he did the first  two issues in this year's competition (the contest year runs July to June).  I don't remember who the other Honorable was, but the winner was the NIRA section in Illinois. I also thought we'd have a chance in the Section of the Year, but we didn't even rate an HM on that one. I'm following up with the coordinator of that award since they say it stresses community outreach, and that's what LUNAR does best.

I came across an interesting tidbit for those of you that are web-enabled. I got an e-mail recently from someone who had visited the Compuserve Sport Rocketry forum. It seems that sysop Doug Pratt has posted his own photo gallery of pictures taken at the meet and there are some familiar faces there. 

For those unfamiliar with him, Doug has been running the S/R forum (which has no connection with the NAR magazine of the same name) for 15 years and declares it the oldest electronic gathering of rocket hobbyists. He is also the author of several books on the hobby including the fundamental "Basics of Model Rocketry" published by Kalmbach. Even though I've exchanged e-mail with Doug many times, I'd never met him face to face until Pittsburgh. He was snapping shots with his digital camera of  just about everyone who was walking by his booth, and he got one of me  with NARTS guy Bill Spadaforda. Later at the "Manufacturers' Forum" at  the hotel he got a shot of me pushing my book project. I've sent these and a few others in with this article and I hope they make it. The originals, and a whole lot more, are visible on the Compuserve forum that starts at: forumsa.compuserve.com/gvforums/default.asp?srv=rocketry

Note that the LUNAR logo appears in both of these shots (and not by accident, I'm constantly pushing our club in the eyes of the national organization).

Finally, Tim Van Milligan, the owner of Apogee Components, has written an article on next year's meet that will be on Vern Estes' ranch from July 29 through August 4, 2000. Even if you've never been to one of these meets before, you might want to start planning for this one. The field is supposedly so big that they will be flying High Power Levels 1, 2 and 3 off the sport range plus holding "fun events" of HPR Scale models in all three levels.

It will be one to see.

A view of the "Old Rocketeers" reunion, but unless you know who these people are, it might not be that interesting. Vern Estes is the second seated one from the left, and Bill Stine (Harry's son and the former head of Quest) is the one standing behind. (JPEG 122KB)
(photo taken by Jack Hagerty)

Peter Alway with the latest edition of "Rockets of the World" which looks just like the other editions, but it shows that I wasn't the only one at the meet pushing a book. :-) (JPEG 63KB)
(photo taken by Jack Hagerty)

NARAM-2000 Returns to Colorado for a Sixth Time!

By Tim Van Milligan

NARAM-2000 Publicity Chairman

It is official, the 42nd annual NARAM will be held in Colorado. The NAR Board of Directors has voted to award the event to the two Colorado clubs of C.R.A.S.H. (Denver) and C.O.S.R.O.C.S. (Colorado Springs). The dates are July 29 through August 4, 2000.

The primary purpose of NARAM is to host a rocketry competition championship to select the best modelers in different age brackets, as well as the best teams and NAR Sections. The events in this contest are:

Research and Development

Giant Sport Scale

D Engine Superroc Altitude

4XA Engine Cluster Altitude (no airstarts and no boosted darts allowed)

C Engine Eggloft Duration

1/4A Engine Parachute Duration (Multi-round)

A Engine Boost Glider Duration

B Engine Streamer Duration

1/2A Engine Helicopter Duration

D Engine Rocket Glider Duration

The rules to these contest events can be found on the NAR¹s web site at: www.nar.org. The Contest Director is Ken Mizoi. He can be reached at (303)-368-5209 or email: kenmizoi@rmi.net.

The site for NARAM-2000 is a 400 acre field that is owned by Vern Estes, the original founder of Estes Industries. In honor of Vern, the site has been named Estesland by the two host clubs. Estesland is located between the two Colorado cities of Canon City, and Penrose. It is about 38 miles southwest of Colorado Springs. On rocket range number two at Estesland will be the sport and high power field.  The sport launch starts the weekend before the contest and runs the entire seven days of the event. The large field can handle most any size models, and a waiver to 10,000 feet AGL will be in place throughout the week, with windows to even higher altitudes available.

In cooperation with the US Space Foundation and the Civil Air Patrol, NARAM-2000 will also play host to a educational rocketry convention. At this special convention, teachers from all over the US will  come in and be taught how model rocketry can be used to motivate students to learn. The will be taught the finer points of rocketry like: how to track a rocket to measure its altitude, using a computer to design a rocket, and how to perform a launch with large groups of students. If you wish to help out with this event, please contact Tim Van Milligan at email address: tvm@apogeerockets.com. If you know a teacher that would like to attend and who needs some extra college credit, please let them to visit the NARAM-2000 web site.

At this time, the two clubs are setting up a variety of special events to coincide with the NARAM launches. This will include tours of the factories where the real space launch vehicles are assembled. More information on these activities and other exciting events will be forthcoming, and will be posted on the special web site: http://www.naram2000.org/.

The web site also contains information on how to register for the event, as well as hotel information and info on local attractions. We urge people that are interested to make hotel reservations by early fall, as summer in Colorado is peak tourist season, and hotel rooms become filled quickly.

This event is open to all modelers, teachers, students, and space enthusiasts. It is not necessary to participate in the contest or even to be a NAR member to enjoy all the activities surrounding this big event. Just be ready to have a lot of fun!

NARAM 2000 Educational Conference

By Tim Van Milligan

Purpose: To provide aerospace educators with in-depth knowledge of model rocketry on subjects such as: designing stable models, operating a safe launch range, rocket propulsion, payloads for model rockets, tracking a rocket¹s altitude, and using rocketry to excite and motivate students to learn. The participants will be totally immersed in the various subjects of rocketry, and will have the opportunity to interact with each other, and members of the National Association of Rocketry (N.A.R.) at the N.A.R.¹s annual rocketry meet.

NARAM-2000 Dates: July 29 to August 4, 2000 (actual conference dates: TBD)

Location: Cañon City, Colorado

Host Organizations: National Association of Rocketry, US Space Foundation, Civil Air Patrol, and the rocketry clubs of Colorado Springs and Denver.

Cost: To Be Determined (expect at least $400 per person). Graduate level credits from the University of Colorado will be available for an extra fee.

Description of the event:

The NARAM 2000 Educational Conference will be held in conjunction with the National Association of Rocketry¹s Annual Meet (N.A.R.A.M.). This will be the first time the NAR has hosted a educational conference to train teachers in the subject of model rocketry. The conference will be limited to 200 participants.

The NARAM event usually draws about 150 highly skilled rocketeers from around the country. The event was started 41 years ago, and has been held yearly in different cities throughout the USA. It has been held in Colorado on five different occasions; the last time being 30 years ago. Over the years, the event has grown from a national contest, and now includes a separate launch range to allow modelers to launch rockets of nearly any size.

The special educational conference will be geared towards teachers that have already built and flown model rockets; and who are looking for more advanced coursework on rocketry; and how to integrate it into different subjects and classes. The participants will attend courses and workshops; and then will get a chance to launch and track model rockets. It will be geared toward the high school level, but with some sessions that have application to lower grades.

While the educational conference is being conducted, the N.A.R. will be conducting its own annual meet at the launch site for its members. The educational conference participants will also have access to this launch field throughout the week, and will participate in a special launch day to try out some of the knowledge they learn during the conference. By having the educational conference coincide with the regular NARAM, the participants will be able to interact and learn even more about rocketry in an actual launch setting. They will eat, sleep, and breath rocketry!

Launch Site: Located between the cities of Penrose and Cañon City, Colorado. On U.S. Highway 50, directly north of the Freemont County airport. The 400 acre parcel of private land is great for rockets of most any size. The waiver from the F.A.A. will allow rockets to be flown to 10,000 feet (above ground level), with authorized launch windows to even higher altitudes.  The field elevation is approximately 5,000 feet above sea level. There are a variety of low growth cactus on the field, so it is recommended that participants wear hiking or cowboy boots when at the launch site. All participants will be required to follow the NAR safety code when flying model rockets at this launch site.

Required Educational Sessions:

Launch Operations -- How to run a safe launch with large groups of students.

Presented by Tim Van Milligan, author of three rocketry books: Model Rocket Design and Construction, 69 Simple Science Fair Projects with Model Rockets: Aeronautics, and Model Rocket Propulsion.

Using Tracking Scopes to Determine a Rocket¹s Peak Altitude (Building session included) -- Dr. Bob Kruetz.

Using and Understanding Rocketry Computer Simulations -- How computers can be used to aid in the design of model rockets. -- Paul Fossey.

Model Rocket Propulsion -- What makes rockets go whoosh. Presented by Mike Dorfler - Senior Designer, Estes Industries.

Electronic Payloads for model Rockets. Presented by Peter Kerckhoff - Dean of Electronics, DyVry Institute of Technology, Kansas City, Missouri.

Rocket Building Session -- Each participant will build a rocket to fly on launch day. While participants will all build the same rocket, they are encouraged to bring completed rockets with them to also fly and gain launch experience. Any size rockets are welcome, as long as the maximum altitude remains below 10,000 feet (above ground level), and that the rockets use motors approved by the N.A.R.

Rocketry Recovery Techniques -- While parachutes and streamers are the most popular methods for returning a rocket to the ground, other methods, such as gliders and helicopters can be used to explain the aerodynamic concepts of lift and drag. Presented by Al De Iglesia

Flying Rockets with Larger Rocket Motors -- Some experiments may require larger rockets with more power. This session will explain what is involved in building bigger rockets, and what legal regulations govern their operation. Presented by Steve Lubliner.

Break-out Sessions:

Steve Bachmeyer - Dade County High School (Florida) - Speaking on Aerospace Education; The Space Shuttle Project.

Ken Horst - Instructor, Goshen High School (Indiana) - Rocketry for High School Students.

Jim Banke - Florida Today Newspaper - A Description of the new Launch Vehicles being produced to further advance man's exploration of outer space.

Dr. Ben Millspaugh - Civil Air Patrol programs.

Richard Speck -  Talking about High-speed, High-performance Rockets; Guidance, and Control.

Mark Bundick - NAR President. NAR benefits for school teachers.

Marc Lavigne - Rocket Scientist; Boeing Corporation. Speaking on how model rocketry mimics the real world of space vehicles, and what it is like to be in the blockhouse when a rocket explodes.

Steve Bachmeyer - Dade County High School (Florida) - W.I.N.G.S.  -- the student organization for Aerospace Education. This sessions will  tie in to all of the sessions and give teachers ACTIVITY to go with what they are learning; especially the launch procedures.

Edward LaBudde - Electronic tracking of model rockets. This session will show how to set up electronic tracking scopes to determine a models flight path. Not only does this determine the rockets peak altitude, but also the actual acceleration, velocity, and range of the model. This is a highly accurate method, and allows precision measurement of the rocket¹s flight.

Ted Mahler - After School Rocket Class for 4th Graders.

Note: The above information is still preliminary. Please check the NARAM web site weekly for updates (www.NARAM2000.org). If you'd like to help with this conference, please contact Tim Van Milligan (email: tvm@apogeerockets.com).

Telephone number: (719)535-9335 (day).