My first Geezer TARC rocket for 2018...

I was suffering from rocket burnout last year at the time of the release of the TARC rules, so I did not get around to building my Geezer TARC rocket until the latter part of Summer. Normally I build two to maximize my chances, but I started so late that I could only complete one before the launch. I have determined I shall not repeat last year, so I got to work designing as soon as the rules for TARC 2019 came out earlier this month. Four completed designs are now stored on my computer, but I am only satisfied that one - christened the Reliant - is sufficiently well thought out to construct. Another will make the grade soon enough, but it'll take a little more work with Open Rocket.

Open Rocket visualization of the Reliant - still trying to decide decor (Click to enlarge).

So what am I looking for in my Geezer TARC entrees?

1) Simple and relatively easy to build - hard to cut straight with my eye condition, so I need fins with simple geometries, like swept trapezoids or deltas. No elliptical shapes, even though those are less draggy.

2) BT-70 based - BT-80 tubes have too much area, hence too much drag (remember we are trying to get to 856 feet this year, 56 feet higher than last year's mark). Centuri ST-18 tubes are "minimum diameter"; a regulation size egg will barely slip into them, but there is no room to pad the egg sides. OK if you land nose down, but bad if you hit on the side of the capsule, especially with 3 eggs inside. A BT-70 is a good compromise between the two. Another plus is that Apogee makes some relatively lightweight egg protection for this tube diameter.

3) A weight around 520-525 grams fully loaded without motor - The fact that this year's rockets have to be painted means added weight. Throw in the additional egg and higher altitude and you may find it extremely hard to make altitude with a BT-80 based bird. Too much drag, too much weight.

4) Assuming the weight range above and a typical rocket drag coefficient of about 0.75, a F motor should get me to about 850 feet. Open Rocket has the model going about 150 feet higher, but it always over estimates altitude.

1st-order altitude prediction for the Reliant (Click to enlarge).

The Reliant meets all these criteria. As you can see from the Open Rocket screen capture, it is very classic, very simple. The fins are balsa laminated with paper to keep weight low and increase durability, and the payload (capsule) section can be loaded from both the front and back to help in getting the eggs in and out - hopefully without breaking. The balsa coupler at the base of the capsule is augmented by a JT70 coupler wood glued to the front to help facilitate insertion of the Apogee 2 egg foam protector, and to add a little strength back there. A hardwood dowel will be glued into the back of the coupler, and the screw eye will be inserted into the dowel. That point - to which the dual parachutes are attached - will take a lot of stress at ejection, and I do not want the screw eye pulling loose (which would make me a prime candidate for the Flying Pig trophy). The rocket is powered by a single 24 mm composite, which is retained by the Estes plastic 24 mm screw-on retainer (available in 3 packs online).

Open Rocket design of the Reliant (Click to enlarge).

As I stated near the beginning of this post, I am pretty confident in this design - so I had to build it. The construction went quickly, and here she is, ready for primer when the stormy weather leaves. Getting started this early gives me the time to work up and build another design, probably a cluster of some sort. I am ahead of the game!

Reliant ready for primer (Click to enlarge).

And I am going to win this year... Mark these words!

I attend rocket camp...

Campers hard at work on a 3" BMS School Rocket (Click to enlarge).

I had the privilege of attending the Hope Christian Academy Rocket Camp this past Friday. Imagine 9 highly motivated kids spending a week devoted totally to rocketry - they covered a great many aspects of the hobby, progressing from stomp rockets to water rockets to model rockets to mid power birds. Along the way they learned the basics of rocket physics and how to use Open Rocket to design their own models. By the time I showed up Friday morning, they had advanced sufficiently far to breeze through the construction of the Balsa Machining 3" School Rocket, and were eager to show me some of their Open Rocket designs. To say I was impressed would be an understatement - one student knew Open Rocket better than I, and he revealed a beautifully rendered simulation of a rocket resembling the old Centuri Taurus. Several of the class plan to be on the Hope Rising TARC team, and so there were also some designs for this year's TARC rocket. It will be interesting to see which one makes the final cut (the team, when assembled, votes on the design that will be used during the season). I thought it appropriate that the members of the camp referred to themselves as "RPGs" (Rocket Powered Geniuses) - they even came up with a camp logo:

My rendition of the Hope 2018 Rocket Camp logo (Click to enlarge).

My progress on builds has been good - I have finished the first rocket on my 2018 build list, a clone of the Centuri Javelin. The Javelin was my first rocket, built and flown 50 years ago, and I had to have another one to commemorate the anniversary. The build was very straightforward, and it marks the first time I have used decals made with my inkjet printer. Past efforts with inkjet decals were pretty ugly, and so I resorted to printing my decals on the color laser printer at work. However, the colors are not as vivid as I would wish, and the toner is often low, so I thought I would try printing with my new HP Envy. The decals came out well, with better color saturation - A successful experiment for once!

Centuri Javelin clone in 1971 catalog decor
(Click to enlarge).

I have started construction on my first Geezer TARC rocket for 2019  - details to follow in another post.

Time to start Geezer TARC!

OK Geezers, now that the rules have been released for the 2019 TARC competition, we can start the annual Geezer TARC contest. This year promises to be fun-filled, with 3 eggs, 3 parachutes, and an altitude goal of 856 feet. I'm looking forward to it!

So here are the rules for 2019 Geezer TARC competition:

The rules are the same as those for the 2019 TARC challenge with the following exceptions:

• Geezer TARC begins with the announcement of the 2019 rules in May (which happened today) and ends with the contestants’ rockets being launched at a single event (date TBD, probably on a Saturday on or near the start of the college football season in September).
• Each contestant may enter up to two rockets. These rockets may not fly before the official launch date, and the score shall be determined by the first flight of each on that date. The contestant's score shall be the better of the two flights, or the score of one flight if only one rocket is entered.
• Contestants must use one of the regulation TARC altimeters (APRA, PNUT, or Firefly) as the "official" measure of altitude. A re-flight will be allowed in the event of an altimeter malfunction, provided the flyer can demonstrate it was not his or her fault (i.e., did not forget to turn it on or provide vent holes to the outside). The altimeter used to record altitude may be used for no other purpose, though the use of a Jolly Logic Chute Release or other altimeter type/flight computer is permitted for flight control.
• There is only one rocket per design, and there are no test or sub-scale flights permitted for the design. Its merit will be judged solely by the rocket’s performance at the contest launch. If two rockets are entered, they must be of substantially different design - different number of motors, fins, or something major - an inch shorter or taller does not constitute a substantial difference, nor does the same design at a different scale.

Good luck everyone!

Odds and ends...

The weather here in Huntsville is heating up as summer approaches; alas, I have not been able to take advantage of the recent favorable conditions by launching rockets, except for three I put up in a school demo. My colleague, Chuck, had arranged with Williams P-8 school to do a rocket lecture/launch for their science week. Unfortunately, he broke his ankle at the NASA SLP (Student Launch Project) launch, making it hard for him to easily get around, much less set up and conduct a launch. I  responded to his call for assistance - I'm always looking for a reason to ditch the innumerable meetings at work - and so 9 AM Monday morning saw Chuck giving a talk to a bunch of 5th graders while I set up my pad on the track field of the school. My launch gear goes together in less than 15 minutes, so I sat down on a bench after placing the first rocket - an Estes ARTF Rookie - on the rod. While checking my email on my phone, I happened to look up and noticed this little bird sitting right on the top of the 1/8" rod, in direct line of fire of the Rookie. Amazed, I moved closer, snapping pics with my phone camera as I approached, hoping to get close enough to get a really good image of this unusual occurrence. It was not to be so - the bird flew away when I was about 40 feet away, too far for the iPhone to get a decent pic. All I got was a few blurry images - How the heck the bird was able to perch on the tip of that skinny rod is beyond me.

Estes Rookie on pad (Click to enlarge).

Bird perched on the rod (Click to enlarge).

Anyway, the demo launch went well. The Rookie put in a fine performance on a B6-4; it was followed by the Estes Meteorite White Crayon, also on a B6-4. The final bird to take to the air was my Quest saucer, powered by a C6-0, after which Chuck amazed the crowd with some of his aerobatics with an RC plane. Several of the kids seemed very interested in the rockets, and asked some pretty good questions about stability and how the rocket motors worked. A good morning, except that I had to return to work.

I managed to finish three models this past week - the clone of the Estes KL-3 Marauder, a Centuri Payloader clone, and a clone of the Centuri Mach 10. I am very happy with the Marauder and the Mach 10; the Payloader seems a bit bland, and I may swap the black trim for the 1964 decor, which featured a checkerboard pattern and the kit name. I have also completed building the clone of the Centuri Stellar Starlifter - after a final sand, it'll be ready for primer. The Javelin is ready for paint, and the Shrox Sniple needs the gray primer sanded off before getting a coat of white primer.

KL-3 Marauder (Click to enlarge).

Centuri Payloader (Click to enlarge).

Centuri Mach 10 clone (Click to enlarge).

Lots to do this weekend...