Brief:
A minimum diameter, piston ejection, streamer duration competition rocket.

Construction:
The kit is a 3FNC that utilizes piston ejection for streamer recovery. The ELM in the name stands for Extremely Low Mass. Heavenly Hobbies states that they use thin, but high quality, competition grade balsa for their fin material. The piston is a NB-20 style nose block with a tiny hole drilled through to slide onto the shock cord. The shock cord is a Quest style arrangement that uses Kevlar® around motor block that is then tied to an elastic shock cord. The nose cone is finely turned with a hole drilled into the base for the elastic cord to be stuffed and epoxied into. Motor retention is a friction fit. The body tube is white with a light glassine coating and very fine spiral grooves. The steamer provided is orange crepe paper. I was able to put this together in just a couple of hours. I used yellow wood glue throughout the construction, CA glue on the Kevlar® knots, and 20 min epoxy to secure the shock cord to the nose cone. Heavenly Hobbies recommends leaving the rocket unfinished if you intend to fly it in competition, just sand down the fins and nose with 400 and then 600 grit sandpaper. I elected to coat the nose with thin CA followed by thinned Elmer's Wood Filler just to cut down on the dents and dings. They also recommend and can supply a tower launch pad for flying this rocket. I am not a competitive flyer so I just used the launch lug provided in the kit. The instructions were eight laser printed pages that included color photos of each step. On the last page of the instructions were the fin template and a circle-and-line drawing for determining fin placement.

PRO: Construction was smooth and logical. The longest part of the construction was waiting for the glue to dry.

CON: Are elastic and Kevlar® shock cords ever long enough?

Finishing:
I did not finish this rocket at all because I wanted to build it just for this review. The only deviations I made were the ones I did to the nose cone.

Construction Rating: 5 out of 5

Flight:
For its maiden flight I used an A8-5. Preparation is simple. Install an igniter in a motor and install the motor in the rocket. With the piston ejection it requires no wadding. I secured the motor by using a strip of masking tape across the bottom of the motor and up the side of the body tube. Fins offset from the base would have helped here.

It took off like a scalded cat! It flew arrow straight and blew the nose cone off while still going up. As this is supposed to a streamer duration rocket I timed the flight. Lift off to landing was just under 25 seconds.

The ejection charge had to have been hot because a good portion of the bottom of the piston was burned away. I can't say if I had the piston bottomed out or not and I don't know if it would have made a difference. Perhaps a coating of epoxy or JB Weld could have done some good here. After the flight the piston fit a bit tighter in the body tube. Launch conditions were a bit cool and damp and that may have had something to do with it. I will need to replace the piston before it flies again.

Recovery:
Again, I think the overall shock cord combination length is too short. I discovered an "Estes dent" in the nose cone's shoulder. The instructions say to have the 1" between the end of the body tube and the end of the piston. Having the piston at the end of the Kevlar® shock cord work be better. Longer elastic may help too.

Flight Rating: 4 out of 5

Summary:
This was a fun and easy build. I would not recommend it as a first kit as the engine block has to be set with an expended motor a new flyer may not have.

Also, increasing the shock cord length and protecting the bottom of the piston would aid in extending the life of the rocket. Offsetting the fins from the base of the body tube would make securing the motor easier,

Overall Rating: 4 out of 5