Andromeda Iris

The Andromeda: This is the original Estes 1977 kit. It was started in 1977 but not finished until 2011! I have added an Iris altimeter payload bay when I completed it. During initial string stability tests, the rocket buckled and folded in half!  To repair, about 2 inches were cut from body tube, so even with the 3 inches of altimeter bay; this rocket is only 1.3 inches longer than the standard model. But it is tall, in fact it is the tallest model in my fleet today, and probably will be for a while.  This was the first of many models to be built with the Iris payload section included in the initial build. This section can be seen in the nose of the rocket between the nose cone and the first silver band.

The two sections are now joined by a coupler; which makes for easier transporting by separating the two halves. To prevent losing the lower half if it ever separates during recovery, I attached a small Kevlar cord between the two halves.  It needed about 19grams of nose-weight to pass string-test, but flies straight up under moderate winds.

This model got a lot of oohs and ahhs at the launch, as nobody else in the local club has one. To me, gloss black seems to look nicer than the recommended flat black. To that I added a small amount of silver trim, around the engine rings, the rectangles on the engine pods, the antennas, and some rings around the body tube ends. This model takes off fairly slow and majestically. With its large fins, I wouldn't want to fly this in stronger winds, as the weather-cocking could (and once did) produce a near lawn dart, and its length would almost guarantee a folded body tube and fractured fins. This rocket has flown higher than the Flatiron Building in NY.

SPECIFICATIONS

Series Number: 17
Number of Stages: 1
Stock Length (post-repair): 41.295"
Iris Payload Length: 3.38"
Total Length with Payload: 44.675"
Lower Diameter: 0.736"
Upper Diameter: 0.98"
Wing/Sail Span: 11.8"
Engine Pod Span: 8.25"
Stock Empty Weight: 101.4 grams
Iris Payload Section Weight: 6.4 grams
Empty Weight with Iris: 108 grams
Liftoff Weight: 138.9 grams
Motor Diameter: 18 mm
Motor Length: 70 mm
Motor Retention Method: Clip
Payload Interior Length: 1.8"
Payload Interior Diameter: 0.95"
Payload Volume: 1.275 cubic inches
Altimeter Capable: Yes
Recovery: 18" Plastic Parachute
Typical Descent Speed: 7 mph
Recovery Protection: Wadding
Shock Cord Mount: Kevlar
Noseweight Mass: 19.4 grams
Fin Material: Balsa Wood
Unique Features: 2 Antennas, 2 Engine Pods, 2 Suspended Conduits
Launch Lug Size: 1/8"
Paint: Krylon Painter's Touch, Gloss Black
Kit Brand: Estes
Construction Started: about 1978
Completed: Aug. 3, 2011

FLIGHT LOGS

2011, August 7: Halifax, Light wind

C6-3: Maiden flight of this rare bird. A lot of people were watching this...and my reputation awaited it's fate.  Flight up was pretty straight, not too fast - a thing of beauty. Ejection at apogee.  Chute deployed and recovered fine.


I wouldn't recommend any other motor for this model. Two shroud lines pulled out from under tape, but landed softly under partial (2/3) parachute (I don't think anybody saw that though). Can't rely on old Estes method of taping shroud lines - they need to be tied or sewn to parachute. The altimeter read 292 feet, good enough!

2011, September 3: Indiantown Gap, Light wind

C6-3: I remembered to turn the larger fins into the wind to reduce weather-cocking (and hoping the model doesn't rotate too quickly after liftoff.) Good slow liftoff, and not much wobble under thrust. Nice ejection and perfect decent under a good chute. Almost caught it in the air.Likely reached 300 feet. Altimeter battery charging circuit died and was not carried on board.

2011, December 4: Penn Manor, Steady 10 mph wind

C6-3: Wanting to collect performance data for this classic, I waited for the winds to lighten up before launching this last, just as the sun was beginning to set. Many rockets were flying directly into the stiff breeze instead of going up on this day. Unfortunately the wind 100 feet up or so continued to blow. The C6 burned for a long 2.3 seconds, accelerating this monster-length, draggy rocket at only 1.2 Gs, peaking at 5.2 Gs.

The takeoff was a straight, slow thing of beauty. At about 100 feet or so it encountered stronger winds and proceeded to turn directly into the wind, going horizontal. It reached a speed of 62 mph and coasted into the wind for another 2.6 seconds before apogee of 218 feet (should be closer to 300). This was another motor with a late ejection charge, taking another .7 seconds to fire instead of .4 seconds.

Still traveling fast, mostly horizontal but heading down, the chute opened at 202 feet, where the winds ripped two shroud lines off. (The string held,the plastic didn't.) It descended slightly fast at 11 mph, meeting the ground in 17.4 seconds with no further damage. The last flight of the day, last flight of the year as the sun sets on 2011.

2012, June 10: Halifax, near calm

C6-3: This model likes light winds for flight, so this was a perfect day. This was to be this rocket’s second data-gathering test flight.  After ignition, acceleration peaked at 6.6 Gs, about 1-1/2 Gs more than the previous flight.  I like to think it was because the new launch lugs were better aligned than the original ones which had some resistance on the launch rod. The 1.8 second burn provided an average acceleration of 1.9 Gs, also a good number. This flight reached a maximum speed of 74 mph, 12 mph better than the previous flight.

I’ve had a lot of short delays on C6 motors and this was also short at 2.7 seconds.  Ejection occurred at 268 feet while still coasting up.  After 1/10 seconds and six more feet it reached apogee of 274 feet. A good parachute opened up to let it sink at 7 mph to a soft grass landing about 100 feet away from the launch area. This was a good and successful flight.

2012, November 23: Penn Manor, moderately light wind

C6-3: I spent way too much precious time in the morning searching for another lost rocket, but at least I found it.  In the meantime, the calm of the early morning was starting to turn breezy, so I had to get this rocket up quickly, as already it was getting borderline.  This tall, heavy rocket lifts off slowly and can be turned too easily by the wind with its large fin area.

The fully loaded C6 motor lit and the rocket climbed slowly but beautifully into the sky. The C6 motor started burning and kicked off with an acceleration of 5.9 Gs, then averaged 1.6 Gs for the two second burn.  It reached a typical maximum speed of 69 mph, it then coasted for the rest of the long 3.4 second delay burn.

It was turning but still gaining altitude when the ejection then fired at 232 feet, and gained an additional 32 feet while the large orange parachute unfurled.  It reached an apogee of 264 feet, and then descended slowly at 8 mph, landing in the grass only about 75 feet from the launch area. Total flight time was 24.2 seconds, and it was a picture-perfect flight.