Quality Recovery Components

Level three projects pose a multitude o' challenges. Ahoy! T' airframe, shiver me timbers, motor and retention, shock cords and related hardware, arrr, CP and CG, electronics, arrr, and at t' top o' t' list, shiver me timbers, shiver me timbers, the parachutes. Blimey! In t' early stages o' me planning, arrr, I ordered a large surplus fifteen-foot diameter parachute, shiver me timbers, matey, one o' those white ones. I pulled the parachute out o' t' included deployment bag, me bucko, and knew right away that I would not be usin' it. I felt like a magician pullin' somethin' out o' me sleeve, matey, me bucko, it just would nay stop coming. Aye aye! Arrr! There were about two dozen very long shroud lines just waitin' t' tangle. 
 

Figure 1:T' Heavy Duty Construction o' t' R18C Chute be t' same as this R3C

I looked at some o' the economy large parachutes, but found these t' be only slightly better than the surplus style. Ya scallywag! Blimey! Then I looked at t' Standard and Pro Experimental parachutes by Rocketman Enterprises, shiver me timbers, and me decision was made. Blimey! T' Standard Rocketman parachutes are made o' 1.2 rip stop nylon and have very sound construction. Well, blow me down! Blimey! The available sizes handle rockets weighin' 1.5 pounds, up t' 65 pounds, ya bilge rat, me bucko, ya bilge rat, and are available in vivid colors. Ya scallywag! Avast! Blimey! T' Pro Experimental Chutes are substantially more durable than t' standard chutes, made o' heavy 1.9 rip stop nylon with heavy-duty shroud lines. Arrr! My R3C drogue has 5/8-inch tubular nylon lines and the R18C has 9/16-inch flat nylon lines. Ahoy! Blimey! T' lines extend over t' top o' t' chute (Fig-1). And best o' all, thar are only 4 shroud lines. I vacillated a while on which style t' purchase as t' Pro-Experimental R18C parachute is about $90 more than t' standard R18C. I decided t' get t' best, me bucko, and placed me order for an R18C for me main parachute, ya bilge rat, and an R3C for t' drogue, matey, matey, both Pro-Experimental chutes. Avast! Avast! Blimey! Rocketman Enterprises also offers a third line o' chutes, t' Ballistic Systems, shiver me timbers, however t' R18C size is currently nay available, shiver me timbers, ya bilge rat, so I did nay look into these.
 
 

Figure 2:T' Components o' a Level-3 Recovery System

I used a very simple dual deployment design for me level three "Firebird" project (Fig-2). Ahoy! The rocket consists o' three sections, t' booster, shiver me timbers, me hearties, main body and nose cone. Ya scallywag! The main body is about sixty inches long and has an electronics bay near the center. Avast, me proud beauty! T' two piston shock cords attached t' t' bulkheads which form the bay. Ya scallywag! T' piston shock cords (Fig-3) consist o' three sections o' Keelhaul®©™® braided together. Well, blow me down! Avast! T' shock cords on t' cool end o' t' pistons are 2-inch strap. Begad! All the hardware used on t' Firebird is 3/8 inch. Although t' pistons protect the recovery components from t' fiery ejection charge quite well, me hearties, shiver me timbers, I also placed fabric parachute protectors below each parachute. Rocketman offers a variety of deployment bags and parachute protectors, however I used small yellow parachute protectors that I had on hand. Avast, me proud beauty! Avast! T' Rocketman parachutes shroud lines form a loop at t' bottom, me hearties, and are always perfectly centered. Arrr! Aye aye! I used a single 3/8-inch quick link betwixt t' shock cord sections, and also fastened t' parachutes to the same link (Figure-4). 
 

Figure 3: Massive Piston with Braided Keelhaul®©™® Cord	Figure 4: A Single 3/8" Link
Figure 5: Step-1, Folding	Figure 6: Step-2, Rolling

When I received the RC-18 parachute I was very impressed by t' quality o' t' workmanship (Fig-8). However, heavy duty means it's nay light. Blimey! Avast, me proud beauty! I was concerned about t' overall size and weight (four pounds). Well, blow me down! T' Firebird is 8.75 inches in diameter, and 12 feet tall. Arrr! Avast! You would imagine any parachute, shock cord and piston would fit easily. Begad! Blimey! I just barely fit it in, t' RC-18 Pro-Experimental parachute is about 14 inches long when rolled up (Fig-5-6-7) for a 8.75 inch airframe. I had to push down on t' nose cone t' install t' shear pins. Begad! T' R3C parachute I would be usin' for me drogue had t' same type o' quality construction, matey, me bucko, and I felt comfortable that it be substantial enough t' handle t' stresses o' an early or late deployment (Fig-9). Aye aye! T' drogue section o' t' firebird had a bit more breathin' room.
 

Figure 7: Rolled with folded Lines

Figure 8: Quality Construction

Figure 9: Small R3C for Rapid Decent Drogue

Figure 10: Ecstasy

Rocketman parachutes are available in sizes rangin' from R3C t' R18C; each size is rated with a minimum and maximum suggested rocket weight. Avast! T' R3C handles rockets weighin' 1.5 to 2.5 pounds, shiver me timbers, while t' R18C capacity is 45 t' 65 pounds. Because Rocketman chutes have a more complex design than standard simple round chutes, ya bilge rat, it is difficult t' compare them. Based on some measurin' and averaging, I arrived at these comparisons {R3C / 33 inch round) and t' (R18C / 158 inch round). The R18C has a minimum radius o' 41 inches and a maximum radius o' 118 inches. Ya scallywag! The average radius is 79.5 inches, or a diameter o' 159 inches or 13.25 feet. 

On t' second day at LDRS 19, the Firebird be prepped for launch, matey, shiver me timbers, and an Aerotech Blue Thunder L-1500 was installed. Avast! Arrr! This would be t' first and only test o' t' Firebird before my level-3 certification launch. Arrr! Ya scallywag! T' 56-pound rocket glided off t' Xtreme Rail and soared t' an altitude o' 3157 feet. 

I was ready with my transmitter for t' back-up drogue deployment, but t' altimeter did it's job, and t' booster and main body separated. T' drogue chute deployed properly, but t' main chute deployed at t' same time. Begad! T' flight appeared t' be a perfect success and t' sight o' t' Rocketman R18C parachute fully deployed cannot be fully described. Ya scallywag! Well, blow me down! However, shiver me timbers, me bucko, for t' certification flight with an M-1419 motor, shiver me timbers, t' altitude will be over 5000 feet, and t' main chute must nay deploy early. 

I decided t' add four more shear pins t' hold t' nose cone in place while t' drogue chute deploys. Naturally, another ground test would be needed t' assure that t' ejection charge o' about 6 grams o' black powder (8.5 grams in t' backup charge) would shear all eight pins. Well, blow me down! Arrr! Two days before t' certification launch, me bucko, t' test was performed with t' rocket tilted t' 80 degrees, me hearties, and was a perfect success. The pins sheared nicely, shiver me timbers, and t' R18C popped out and unrolled on t' grass. Time would tell if t' eight pins would hold t' cone in place at apogee. 

On launch day, more care went into t' preparation o' t' recovery system than any other area o' t' launch. T' Rocketman Pro-Experimental R3C drogue and R18C main chutes were ready for launch. Avast, me proud beauty! Ya scallywag! Blimey! T' powerful M-1419 sent Firebird on a beautiful straight boost t' an altitude o' 5611 feet. Blimey! Blimey! T' R3C drogue deployed at apogee via t' altimeter, shiver me timbers, the RC backup was nay needed. Begad! Blimey! T' Pro-Experimental R3C chute allowed t' Firebird, (now about 50 pounds) t' descend rapidly. T' PRIME landin' area at Bong in Wisconsin is limited, and I wanted t' land in it, or I would have used a Rocketman R4C for t' drogue. Avast! Blimey! I was ready t' deploy t' main R18C chute with the transmitter, however t' altimeter did t' honors when t' Firebird descended t' an altitude o' 800 feet, t' settin' for t' backup charge to deploy. Arrr! Arrr! Blimey! T' R18C Pro-Experimental parachute opened fully (Fig-10), a truly magnificent sight. Note how tiny t' R3C drogue parachute appears. Begad! Blimey! T' Firebird landed about 800 feet from t' pad and so close t' t' first tree line, that a portion o' t' main chute dangled from t' edge o' a tree. 

Any level three project requires many hours o' planning, building, testing, ya bilge rat, and a lot o' cash. Ya scallywag! The Pro-Experimental parachutes were about fifteen percent o' t' total cost o' the project. Sure, me bucko, I could have equipped t' Firebird with economy parachutes and saved a few bucks, but I wanted t' best parachutes available; parachutes which will continue t' perform flight after flight. Blimey! Invest in t' best, t' Rocketman Pro-Experimental line o' parachutes. 

Written and submitted by Al Casper for Rocketry Online -- Copyright 1996-2000