Brief:
Single-stage, single-engine rocket with piston ejection system and is suitable for Level 1 attempts.

Construction:
This Aerotech rocket has the standard Aerotech through the wall Fin-Lok™ system and components except the nose cone is a different material than the other Aerotech's. It is gray and presumably stronger. It has 4 fins about the size of the Astrobee D but reported thinner than the Astrobee. Even though it is only 3' tall, the shock cord is 18' long! I asked Aerotech why and they said as the cord gets wear and tear at the engine end, it can be cut shorter. The shock cord is attached to the top of the motor mount using a eye screw like other Aerotech's but for the SUMO you don't glue the screw in. That way you can unscrew it and fix or replace the cord. You can do this easy because after installation, the top of the engine tube is only a foot or so below the top of the rocket.

Also note that this Aerotech has 2 other differences from the normal Aerotech's. First, there is no engine thrust ring inside the engine tube. So you can fit all G and many 29 mm H RMS engines without problem. It does have the engine hook and when using the 29/40-120 RMS casting, you need a yellow spacer (provided). Secondly, it has a piston which ejects the parachute. The piston must be epoxied, not super glued together. The 18' shock cord is attached at the engine tube, runs through the piston and on to the nose cone.

The instructions are typical for Aerotech and are very good. They include a parts list, good photos, spec data, prep information, etc. Super glue is used everywhere except for the piston. This is a level 1 capable rocket taking up to an H210 motor. I assume if Aerotech says it is OK, super glue will work although many I know will use epoxy instead. I built per the instructions using super glue for everything except the piston (using epoxy for that) and it weighed in at 32 ozs. Using only epoxy will add weight.

The assembly process is the standard Aerotech flow, motor mount, fins, etc. Because this rocket uses the piston, there is no metal mesh installed inside the engine tube. Also, as stated above, the shock cord is screwed into a blast deflector bulkhead and into the motor mount but it is not glue in.

The only problems I had with the assembly were related to the piston. First, they supply two clamps which are suppose to be snapped to the shock cord above and below the piston. These clamps are suppose to hold the piston on the cord. There is no good picture of this in the instructions. I couldn't get the clamps to lock down tight enough. They allowed the piston to slide along the cord so I didn't use the clamps. I just tied a big knot on both sides of the piston bulkhead and it worked good. Second, I couldn't get the piston into the body tube. It was too big. The instructions said nothing about this so I called Aerotech and they sounded surprised and said they didn't have a problem. But then I told them where I lived and how humid it had been and then they concluded it must have expanded the piston. So I lightly sanded the piston until it fit snug in the tube.

Finishing:
I painted and put the decals on my rocket per Aerotech's model. The decal sheet for this short rocket is one of the largest I have ever seen! After painting the rocket red and yellow, I applied the decals and I think it looks great. I rate the construction 4.5 because the instructions could be a little bit better concerning the piston and its installation.

Construction Rating: 4

Flight:
The smallest motor for this rocket is a G35, the largest is an H210. I flew it on a G64-4 without problem. At the same time, a friend of mine flew his for his Level 1 with an H128 with no problems. There was a 5-12 mph wind and my rocket went straight up until near apogee when it started to angle but by that time the chute opened.

There is a minor problem with preparing the rocket for flight. Because this rocket is so short and the engine tube is quite long, and the shock cord is so long, plus there is a piston and chute that all has to go in, it takes a little bit of careful packing to get the nose cone to go all the way down. If you pack the chute compactly, you can just fit everything in. Because of the piston, no wadding is needed but you have to be careful with the ejection charge. Like all piston ejection systems, if you go overboard on the black power, you'll damage the piston. Aerotech gives you some guidelines to go by. Also, because you can use both medium and high power engines, there are 2 engine spacers you may need to get the engine hook to click in where it should. Also, Aerotech recommends you use 1" masking tape to seal the engine in place to ensure there is enough pressure to eject the piston.

Recovery:
Recovery is using a standard 22" yellow Aerotech 'chute. The shock cord length and 'chute size are adequate for this rocket. On its first flight, the rear of the body tube had some minor dents in it. I don't know where they came from, either the nose cone or piston must of hit it after ejection. The engine is recessed a good bit in this design and therefore the body tube at the bottom of the rocket is a little bit weak. I would rate recovery 4/5 because of the body tube damage and care needed to pack everything.

Flight Rating: 4

Summary:
This is a nice short and fat rocket that many people will like. It will fly high power or medium power motors. With a G64, about 800', up to about 2800' with an H210. It uses a piston ejection system so no wadding or other protection is needed. It has through the wall and to the engine fin mounting which makes for a strong design. I have never lost a fin on an Aerotech despite some hard landings. The shock cord is exposed to the motor blast and will dry out and fail over time. Unlike other rockets, it is easy to replace the cord in this rocket. A little bit of care is needed in using bp for the ejection and in the packing of the shock cord, piston and chute. If you follow the paint scheme suggested by Aerotech, you'll have a very bright and colorful Level 1 rocket capable of flying on G engines. I would rate this rocket overall 4.5/5 for all the reasons stated above.

Overall Rating: 4