Finished: My Semrock Space Shuttle

[rifleshooter]

Semroc (should be SemRAWKS!) Space Shuttle Build (crossposted in the low-power forum for readership)

As a muddle-aged B.A.R., I thought I'd relive my model-building youth with a nice, easy-to-construct rocket-boosted glider.

Few who've ever met me have confused me with someone who possesses any common sense.

The amount of lumber in this kit could have built a doghouse for my cattle-dog mix - and being the meticulous, careful, ignorant perfectionist that I am, I had to sand and fill the lumber like 18 times. Additionally, I added 42% more wing area to the Orbiter because I live at 5300 ft and wanted something with a glide-ratio higher than a brick's.

Here's the build. It took me something like two weeks, what with carefully working on the pop-pod separation to smooth it out, the 2.5 gallons of paint I put on the model, etc. This was not a build for the weak-at-heart (or weak-at-skills, as it may be).

Final weights on this model:

93 g (3.2 oz) unloaded.

The Booster weighs 58 g (2.0 oz).

The Orbiter weighs 20.72 g (0.7 oz).

The Pop-Pod weighs 12 g (0.4 oz)

How do these masses compare to your Semroc SS?

Things I am aware of: I know I put the wrong windows on each part of the rocket. Yes, I forgot to put some of the 7 (!) launch lugs on until after paint/decals went onto the kit. My filleting skills can be described as "in need of development." Yes, I used a hobby knife to cut the masking tape too deeply on both Orbiter and Booster.

I await your criticism - it is through constructive criticism that we become better.

Anybody with RocketSim wanna tell me what this thing will do with 0-wind, straight flight on an Estes C6-3 motor?

P.S. Semroc kicks butt. The balsa was NICE. They quickly, and for $0, sent me out some parts of a pop-pod after my thrust ring got stuck due to the inappropriate glue I used binding the ring.

 

[rifleshooter]

A flight report on the Shuttle:

I joined the crew of Northern Colorado Rocketry Club at their Atlas site this morning for the monthly club launch. A tougher bunch of steely-eyed missle men have seldom been seen! Actually, these guys are all really kind-hearted folks who'd give you the shirt off their backs without you askin'!

Winds were light, perhaps 2 mph, and temperatures were low - the mercury never climbed higher than 3 degrees C (about 37 degrees F) all day. Skies were partly cloudy with Easterlies (very uncommon around here, unless snow's coming - stay tuned). The Atlas site is very nicely laid out, with an asphalted road leading through the parking area, and concreted pads available for high-power.

I approached the low-power pad with trepidation - after all, ,my over-engineered nightmare was about to get up into the sky! The drama of the Semroc Space Shuttle was about to start.

As I slid the rocket-glider down over the launch rod, I noticed the lug came loose. Rolling my eyes, I tried the other launch lug - and it broke off as well. Bear, a nice feller who offered CA, activator and a corner of a table, got me back on track, and I fired the Shuttle off.

Things looked great for 10 feet, then disaster struck - I had heard that these shuttles like to arc over their fore-end owing to the off-center thrust, and so I heard that you need to roll in the trim a fair piece to fight against this. Additionally I put the top of the rocket facing the wind so that weathercocking would fight that tendancy as well.

The combination of trim and weather-cocking wickedly over-compensated for the off-axis thrust and the bird looped in a 50' circle, flying under power to a horizontal attitude with the ground. This made for a rough powered landing and a separation on the deck which resulted in a minor prarie fire, which also consumed my pop-pod's streamer!

Not a great way to make a first impression in front of the club president and launch director.

I flew my Estes Bullpup to give me some good flying experience (it flew like an arrow - what a great model!), then I flew the Shuttle again.

This time, I took out about 50% of the trim and put the top of the shuttle facing downwind. This turns out to have over-corrected the problem and the thrust-nose-over had the shuttle climb to about 50 feet, then nose over slightly - towards the parking lot and a group of rocketeers. Once again, the combo was flying stably horizontal to the deck, this time at about 25 feet. Separation was well performed. The Orbital Transport is trimmed to stall and could likely use some nose weight or me to take some elevator out of the equation. The Booster flies quite well both with and without the mass of the pop-pod and Transport. Both gliders landed without hitting anybody and the club all got a big laugh out of the adventure.

I will fly this model again so I can get the feel of how I need to trim it for the wind so I can get good flights out of it.

 

[philip]

A great looking model beautifully finished but difficult to fly well. Can't have everything i guess!

 

[okey0]

HA-mine flew the exact same way on first launch, as well as started a small prarie fire! i traced the problem to a weak engine mount that allowed the pop pod to go off kilter at launch. I ironed out the wrinkles in the body tubes, reinforced the mount, and the next launch was perfect. Havent flown since though.

I think the build looks just fine.