by Bill Cooke
TARC is like the real world of rocket design in that the teams must resort to design/simulation software to help flesh out the initial concept, making sure it can meet the goals before pressing on to actual construction/testing. Here the vendors have come to the rescue in providing three outstanding packages, any one of which can be used to design a winning TARC entry. Read more
by Bill Cooke
NAR and the AIAA have just released the objectives for the 2013 TARC season. In brief, they are
At first glance. this seems simple; after all, each of these has been used in past years. No surprises, so pretty easy challenge for the TARC teams, right? Read more
by Bill Cooke
Every year Cub Scout Pack 351 has their annual ‘rocket blast’, in which the cubs fly rockets they have recently bought or built. HARA – in the form of Chuck Pierce and various others who show up to assist – always provides the launch setup and range control, which has been fairly easy for the past couple of years due to the use of the USSRC/Space Camp launch facilities. Read more
by Vince Huegele
As the 2012 school year winds down HARA has been busy with launch demonstrations. On May 3 we were set to fly for the 4-H Urban Youth Farm Day at the A&M field in Hazel Green, but steady showers scrubbed the launch. The facility has a building that could hold all 300 kids so 4-H held the event inside. Read more
By Bill Cooke
A lot of the new rockets come with “peel ‘n stick” stickers these days, rather than decals. Many rocketeers call these “peel ‘n cuss”, because they are not much fun to apply (especially roll patterns and long names) due to their stickiness – very little room to make a mistake. Read more
by Daniel Cavender
Last year, the field at Manchester, TN was planted half in sod and half in corn posing certain logistical challenges regarding recovery. There were several rockets that were lost in the tall corn and never recovered. One rocket made its way into an unfortunate combine and did significant damage. That issue is being resolved, and to our benefit, the field is all sod this year. HARA is implementing some new range safety practices to mitigate any further such incidents, but good launch site stewardship is the responsibility of every flyer. All flyers with rockets built using fiberglass, metallic, and other dense materials may be asked to outfit their rocket with a sonic beacon (if not already equipped with GPS or radio beacon). To help flyers find these beacons, this product review will examine two products: the LG personal security keychain alarm, and the Adept SB1 sonic beacon.
LG Personal Security Keychain Alarm
The LG keychain alarm is a very cheap and very loud device that can be quickly pressed into service as a sonic rocket recovery beacon. The alarm needs to be taped to the shock chord. The trigger device is a pull pin that takes about 2 lbs of force to trigger. HARA President, Ray Cole, flew one of these beacons at the March launch and it worked great. They were on sale for $4.95 at Lowes. The batteries are replaceable and the case is robust and provides protection from moisture and BP residue. At $4.95, this is a piece of insurance that will pay for itself time and time again.
Adept SB1 Sonic Locator Beacon
The SB1 is a small 90 dB sonic beacon designed for rockets. It can fit in the body tube of a 29mm rocket. The trigger device is a jumper tied to the shock cord that pulls off of two wires on the back of the SB1.The SB1 needs to be taped to the shock cord against the trigger and jumper. This is a poor design and did not work too well in the field. The jumper fell off easily during packing. The open unit made it prone to damage from the littlest amount of moisture or BP residue. Compared to the $5 option from a hardware store, the SB1 did not hold up.
by Bill Cooke
Estes Executioner built and painted by Kimble29 on Ye Olde Rocket Forum
Now that the primer has been applied, we can move on to the paint. The type of paint is the rocketeer’s choice, with many choosing Rustoleum spray, while others use the same Testors enamels used to paint model cars or planes. The more artistic among us will break out the air brush, producing magnificent finishes like that on the Executioner seen at right. Whatever your paint choice, be sure you read the directions on the can or bottle, and follow them – a lot of weeping and gnashing of teeth can be saved by knowing the drying and recoat time of your paint.
Also, it is important to avoid mixing paint brands or types, as this can lead to “crazing”, in which incompatibilities in the chemistry of the paints cause huge cracks and wrinkles in the finish. However, there may be times – usually due to the unavailability of a certain color – when you have to mix brands or types. In these cases, remember that enamels can be applied over lacquer-based paints such as Rustoleum or Krylon, but lacquers cannot be applied over enamels. Similarly, fluorescent paints should be the last coat, as they will craze any type of paint applied over them (I know this from bitter experience). When mixing different brands, such as Rustoleum and Krylon, the best thing to do is to test out the application on a unpainted scrap piece of body tube. Spray the paint on in the order you intend to use with the model, and see if there are any issues. If nothing materializes, you are good to go.
When working outdoors or in an open garage, be mindful of the wind and humidity. The wind part is obvious – you don’t want paint going everywhere and creating a spotty finish on the rocket. Avoid spraying when the humidity is higher than 50%, as this will lead to the paint dulling or “blushing” (areas where the paint appears duller than its surroundings). Here in the South, we have constant high humidity, but it usually drops below 50% between 2 and 4 in the afternoons, providing a couple of hours suitable for painting.
When painting, spray continous light coats down the entire rocket – don’t “spot paint”, as this will create an uneven finish (which means sanding) and don’t lay it on too thick, as this will cause the paint to run. With Krylon, I usually hold the spray can about 10 to 12 inches from the rocket; this same distance should be about right for Rustoleum and other sprays. Start with the lightest color first and then move on to successively darker colors, saving black for last – be sure to allow the right amount of drying time between coats! No matter what the paint scheme, I always apply a coat of gloss or semi-gloss white above the gray primer to serve as a base coat, as applying yellows or other light colors directly on top of the primer results in very dark versions of these colors. White is always a good place to start.
As I mentioned in an earlier post, I use Tamiya masking type to mask off areas of the rocket when painting. You can avoid bleeds and smudges by
Here are the Rogue and Aero-Hi after painting – note the nice sharp lines. I am reasonably pleased with how these turned out, so we are now ready for the final step – applying the decals, which will be covered in Part 7.
by Vince Huegele
Westminster Christian Academy won the regional TARC contest March 17, 2012 in the best attended launch since HARA began hosting the event at Bragg’s farm. Westminster Christian has been in TARC since 2006 with only modest results each year, but this team scored a ‘4’ for a school record. These points are likely good enough for an invitation to the finals in Virginia, May 12.
A TARC rocket sits on the pad in the last second before lift off
Westlawn Middle School took second place and Williams Middle was third. Ten teams from seven schools participated and flew their egg carrying rockets in unseasonably warm and calm skies. This was twice the number of teams that came out last year so we thank everyone for supporting this very successful launch. There were a total of twenty-five TARC flights, most of which were for practice but ten were formal qualification attempts. Six flights were successful and scored points.
Liberty Middle 1 and Ridgeland High of Rossville, Ga. made practice flights only. Ridgeland’s second flight was great and would have been a ’27,’ but rocket damage in a subsequent flight kept them from attempting points. Madison Academy had parachute deployment problems and Bob Jones had an uncooperative altimeter.
All capsules contained two eggs and had to be flown on an “F” motor or less. The target altitude was 800’ but those flights that hit the 43-47 second duration window were rewarded with a zero time deduction.
This year’s trophies
The trophies were beautiful models donated by United Launch Alliance and were awarded to the top three places. Over seventy people were on hand to watch the launches. Vince Huegele and Bill Cooke provided the local officiating to qualify the flights as well as mentoring the teams throughout the year. Teams have until the deadline on April 2 to complete their qualification attempts.
Vince Huegele presents the first place award to Westminster Christian Academy team members Charles Nottingham, Nicholas Kromann (Team Lead), Ben Cyr, and Shane Nelson.
Ray Cole and David Bishop also had the HARA range set up for whatever members wanted to fly. There were 27 sport flights, nine of which were HP and three of them L1 certification attempts.
A Madcow Patriot takes to the skies on an I motor
By Bill Cooke
Here are 3 of the laminated fins for the Rogue before attachment. This picture is important, not so much due to the fins, but because of the makeshift tool just above them. Consisting of a strip of 400 grit sandpaper glued to a popsicle stick, it is very useful for sanding those small or hard-to-get-at areas of the rocket – in this case, the edges of the Rogue fins. You will often find yourself constructing such tools as you move on to harder, more elaborate builds or HPR; for example, I know quite a few rocketeers who glue sandpaper strips to dowels to help them sand smooth epoxy filets.
The Rogue fins and launch lug were attached to the rocket and filleted, just like the Aero Hi. After the glue dried, I applied sanding sealer to the balsa parts of both rockets to fill the balsa grain. There are a lot of different ways to do this, but no matter which mehod you choose, it will involve multiple coats and a fair amount of sanding. My technique is as follows:
If you have sanded the sides of your fins before cutting or removing them from the balsa sheet, you should have a nice, glassy-smooth surface. If not, apply another coat of sanding sealer, wait 45 minutes, and sand with 400 grit. Repeat until the grain is filled and the surface is smooth. Unless the balsa grain is deep, I usually find 4 coats is enough for fins; nose cones usually take 5.
After the sealer has dried overnight, you can then prime the rocket. Choice of primer varies from rocketeer to rocketeer – I use Krylon Industrial, again because it is forgiving, but others swear by Rustoleum, Valspar, or even Walmart brand (cheap, but it works). Some even try fill the grain and prime in one step by using Kilz sealer-primer. I tried this stuff once, when I built my Thrustline D-Region Tomahawk – it turned out to be Chuck Pierce’s worst nightmare, taking me 2 days to sand out all the bubbles to get a smooth finish. Plus, you could have probably buried me in all the dust that was produced.
Anyway, apply a coat of primer to the rocket, wait a few hours or a day or so (depending on drying time), and sand most of it off with 240/320 grit sandpaper. The pic below shows the bottom part of Rogue after this has been done.
The primer not only helps prepare the rocket for the paint, it also shows any imperfections in the finish – nicks, especially deep grain, scratches, uneven fillets, and so forth – enabling you to take corrective steps. For uneven fillets, I usually add another layer of glue, smoothing it out with a damp finger. Balsa nicks and scratches, as well as many other things, are usually fixed by applying thinned Fill N Finish to the area. This Elmer’s product is indispensable in producing good looking mod rocs, so be sure you go out and buy some. In the pic above, you can see where I have applied Fill N Finish to the non-papered edges of the Rogue fins to cover the cracks and imperfections. I am also building the BMS Mini Bomarc, which is shown below. Note that I have used Fill N Finish to fix nicks and scratches in the balsa wings, as well as an edge defect at the bottom of the right wing.
After fixing the imperfections (be sure to sand the Fill N Finish smooth), apply a second coat of primer, let dry, and sand with 400 grit. The rocket should now feel as smooth as a baby’s bottom; if not, you have more priming and sanding to do (more the latter I’m afraid).
Now on Part 6 – painting.
By Bill Cooke
After assembling the motor mounts, the next step is to mark the body tubes for the fins and launch lugs. The Estes marking guides make this easy – once you’ve decided which end of the body tube is the bottom 🙂
The v-shaped plastic widget is then used to draw the lines on the tubes:
Before I started attaching the fins to the Aero-Hi tube, I pulled out my box of Avery full sheet labels to start laminating the Rogue fins. Once again, this is simple – cut the sheet to size and press the fins down on the label paper, making sure there are no bubbles. I then placed a sheet of wax paper over the fins and let them sit under a stack of books overnight to make sure the adhesive ‘sticks’ well. Then trace around the fin with a sharp hobby knife and repeat for the other side.
Fin attachment is one of the hardest parts of rocket building for newbies (It sure was for my 10 year old self) – it needn’t be. All you have to do is to remember to use the ‘double glue’ technique, which is spelled out in the Handbook of Model Rocketry:
“…when gluing porous materials such as paper or wood you coat both surfaces with a layer of glue or bonding agent and let both surfaces dry. Then coat both surfaces again and join them together. The first coat of glue on both surfaces penetrates the pores of the material. The second glue coat is then free to join with the first coat and with the second coat on the other surface. A double glue joint will be so strong that the materials will break or tear before the glue joint turns loose.“
If you follow the above, you will find that the fin will grab the body tube almost instantly with the second coat, eliminating the frustrating “the darn fin fell off” situation. The strength part is also correct; I have had fins break, but never come loose from the body tube since I have used double glue joints.
It is now pretty easy to attach the fins, launch lug, and simulated conduit to the Aero-Hi:
After letting the fins dry overnight, I applied fillets of wood glue. Wood glue shrinks (as does white glue), so I use my finger to apply 3 successive glue layers to make the fillet, allowing a little time to dry between layers. This results in very nice and smooth fillets. I then did the same for the launch lug.
More in Part 5…
