Weather was not the best this morning. Sunny but a fair bit of wind. So I ended up waiting until 16:00 to pack up 4 of the rockets and head out. We took:
Lucky for you readers, I forgot to take my camera so no video, no photos, just a quick accounting (for my records really).
We picked up 2 packs of mini-motors at the hobby shop. A set of 1/2A4-T (twice the power of the mini’s used previous in the Swift and SkyStreak), and pack of A10-PT which has A LOT more power than the 1/4A’s, something like 4 to 8x the power. We’d already had issues finding the little swift with the small motors. However it is wearing it’s new all-orange paint scheme so, I was willing to ‘risk it’.
220 Swift
Following the re-construction and repainting of the rocket, it’s nose-down descent profile does not seem to have improved. There is a certain amount of danger in one of these things coming down nose first at maximum velocity, so I’m considering permanent retirement of this specific rocket.
1/2A3-4T – (8.3 Newtons thrust) This motor has a max thrust of 8.3 Newtons, which has quite a bit more power than the engine we first used (1/4A3-3T – 4.9 Newtons). Against a white sky, this put the high-vis mini-rocket completely out of site. Thankfully the change to hi-vis orange was critical to use finding the rocket. The engine ejected as designed (un-recovered) but the rocket still descended nose down.
A10-PT – (13.0 Newtons thrust) First off. Don’t use this engine in a rocket. It has a max thrust of 13.0 Newtons. Plenty to get a rocket off the pad. HOWEVER, it turns out the ‘P‘ designation means ‘plugged‘. Plugged engines have no ejection charge. This completely explains why the two flights we made with this motor, the rocket cam down very rapidly with engine still in the body. There seemed to be a trace but NO ejection charge of any kind. With that much additional thrust the little rocket was quickly out of sight! GONE! Hasta la Vista baby!! Again, because of the high fis paint, I spotted the fins of the 4″ rocket sticking out of the grass about 150 yards away (thank God for my still better than 20/20 vision at age 45). I have 2 more of these engines, not sure what I’ll do with them now. :/
Viking
First flights for this school project class rocket. This was also my daughters first rocket project! It came out great and I have to say it flew great too! This is a streamer recovery rocket, like the Hi-Flier so it can be used in smaller fields.
A8-5 – (10.7 Newtons Thrust) First flights should always be done with a smaller motor. This specific rocket does not have an engine retainer (engine ejection expected?) but also has the streamer recovery with nose-blow actuation already noted. Flight was perfect. Straight up! Most predicatable flying rocket we have right now. Engine ejected (recovered) and so did the streamer. Rocket landed close to launch location. Could not have asked for a better launch evolution.
B6-4 – (12.1 Newtons) Sure, I like to push it a bit. We were able to visually track the rocket with the A engine. Launch put the rocket out of my visual range. Again, the high-vis orange allowed a recovery. Unfortunately, this time the engine did not eject from the rocket bods and it descended a little faster than before. Upon landing the fin with launch lug attached was snapped off. They were located together so it’s very unlikely it happend during flight. Back to repair shop for this one.
Hi-Flier
Another lesson learned the hard way, camouflage paint on a rocket might ‘look’ cool but in practice it’s a real pain in but to find them once they land. One thing to note about this rocket. Fly in light wind only. the CP (Center of Pressure) is far enough behind the CG (Center of Gravity) that it windcocks like mad in even a breeze. Windcock? That means it turns upwind due to the aerodynamic pressure on the over-sized fin area. Despite directing the launch rod slightly downwind on the 2nd lauch it still curved upwind.
A8-5 (10.7 Newtons Thrust) – This rocket has been flown many times with this engine. The difference this time time? The streamer did not unravel! Perhaps having it packed in the body all week awaiting our next trip to the range formed it into a ball. Whatever the reason, the thing came down like a rock from 600+ feet, landing with nice little thud, only a few yards away. No damage noticed on vehicle. Ready to launch again.
C6-5 ( 15.3 Newtons thrust) – Why not tempt fate a bit, right? Again he rocket turned up wind. With the higher impulse engine it really REALLY took off. With the 5 second tracking trace I was able to spot it pretty easily in the sky. While visually tracking it, a hoopie-mobile drove past my car making a sound like it had hit it! This distracted me (and my son). I was unable to visually re-acquire the rocket. Having lost a track on it, combined with my brilliant idea to paint it in a camouflage pattern, IT’S LOST. We walked the entire downrange area and after 30 minutes decided to call off the search. So far, it’s not been recovered.
Taser
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Our roof top tardy Rocket flies again! This is another one of those really nice fliers. Good aerodynamic balance. This is the rocket that came in our launch kit, and the 1st one we built. Also the one that was lost on the roof of the Gym for a day, eventually taking a short bath in the rain gutter of the school. There is some damage to the lower section of the main body, a little delamination of the tube and somewhat of a soft spot. It’s flying just find though.
The last time we used a larger motor (a B engine) we lost it on top of the school. Since that time I’ve cut 6 1″ slits in the top of the parachute, and most recently opened up a large hole in the center of the chute to further accelerate it’s descent. A good decision.
C6-5 ( 15.3 Newtons thrust) – I had a few of these engines laying around that were given to me (age unknown). Time to use up another motor. Lift off was again straight up. And up, and up! GONE! It went into the low clouds and was GONE. Oh boy. A few seconds later I was able to see it coming down on it’s chute. Yeah! Except it seemed a little too far away, and still drifting downwind. It quickly became clear this was NOT going to land in our LZ. We watched as it drifted above the school and finally out of view over the roof.
Told the boy to pack the gear and hop in the car. If we were lucky it would have completely cleared the entire school and we’d be able to find it. The school is no longer used and most of the grounds are closed off with cyclone fencing making search really difficult. As luck would have it, as I pulled into on of the parking lots on the other side of the school, I noticed something like a pile of trash (amounts all the rest of the trash) right in front of the car that looked odd. Walking over to it, I saw the rocket under the white parachute and completely in tact. YES! Got lucky and got the rocket back! I’m thinking of removing the chute completely and going to a streamer recovery on this one too.
Engine Chart
I finally located an engine chart for the motors that Estes builds. The Estes Rocketry website had nothing but dead links. Luckily their websites is wildly insecure, providing an OPEN INDEX of the their downloads directory.
The direct link to the current engine chart is here: Estes Engine Chart PDF. I’ve also downloaded the sheet and am hosting here on my blog, just in case they move it again. Estes Engine Chart
Conclusions
Wind: Don’t launch in wind, it will just frustrate recovery, and if you have a model with over-sized fins it could mean it that it will run far up-range and possibly make recovery unavailable.
Paint: There is a reason space agencies paint test rockets in orange, they want to be able to see them. The same goes for model rockets. Sure, it’s nice to give them slick paint jobs, nice starburst fades, cool colors and all that. However, if you are unable to keep an eye on the rocket (it’s small, it flyies too high, whatever) painting it in a not-so-cool boring high-vis orange is a BIG plus. Right now I’m repainting the black sections of our Taser in orange for easier location if it goes out of visual range again, as I suspect it will.
Hi,
We want to launch off our Comanche 3, three stage rocket that goes 2,600 ft. Where is a good place to launch? We live on Bainbridge. And thanks for all the great info!