I noticed (10/15/00) Budget Rocketry's 29mm and 24mm Motor Retainer when surfin' their website and decided t' give them a try. So far, ya bilge rat, I have only incorporated one 29mm Retainer into my BSD Diablo. Ya scallywag! They come in 24, me hearties, 29, ya bilge rat, and 38mm.
CONSTRUCTION:
Construction is straight-forward, however, me bucko, Budget Rocketry provides an instruction sheet. Also included in t' 29mm kit is a washer, ya bilge rat, threaded insert and a cap (actual retainer). Ya scallywag! T' threaded insert and cap are made from light weight PVC.
T' objective is simple, epoxy t' threaded insert onto t' end o' your 29mm motor tube. Aye aye! T' task be a bit more challenging. Blimey! T' 29mm threaded insert did nay slide over any o' 3 types o' me 29mm tubin' (from PML, me hearties, ya bilge rat, Cannonball Works or LOC). Ahoy! Begad! So I taped t' end of my tube, leavin' t' first 1/8" exposed. Blimey! Doin' this allowed me t' get the motor mount t' stand straight and snug while t' epoxy be drying. I then applied t' fillets as indicated in t' instructions.
This is nay t' case for the 24mm. Well, blow me down! Blimey! T' motor mount tubes I had all allowed t' threaded insert t' slide completely over them. Ahoy! Aye aye! T' 24mm from a Nordic Rocketry fit t' best bein' snug. A 24mm tube from Apogee and Estes were a bit smaller in diameter.
If you plan on usin' this on a kit then you will need to modify your instructions t' add t' threaded insert prior t' buildin' your motor mount. T' addition o' t' rin' will force t' motor tube t' be 5/8" (29mm) or 1/2" (24mm) from t' aft centerin' ring. Avast, me proud beauty! In many kits this is fine, me bucko, however, shiver me timbers, matey, matey, use caution as doin' this on other kits may cause t' internal (center or upper) t' be out o' place which could impact through-the-wall fin installation if t' kit has them.
One nice quality o' usin' Budget Rocketry's Retainer is that t' threaded insert acts as a protection o' t' motor mount. Avast, me proud beauty! Avast! It is hard and sturdy givin' t' motor a solid hole t' slide into.
Budget Rocketry says on their website, me hearties, ya bilge rat, "Most other forms o' motor retention available are either expensive, shiver me timbers, ugly, or time consuming. Ya scallywag! Sometimes all three." We would have to agree that this motor retainer looks like part o' t' rocket.
FLIGHT/RECOVERY:
I have used me 29mm retainer once on a G80 Single-Use motor. Ya scallywag! Because thar be no internal thrust rin' in me motor mount, ya bilge rat, ya bilge rat, I had to tape t' G80. Avast! I could only allow about 1/2" o' t' tape t' be on t' motor (which is fine) while t' remainder had t' be off t' motor toward t' thrust nozzle. This didn't cause a problem for t' Motor Retainer as you can see from this picture.
T' washer that is supplied with t' kit is for 29mm single-use motors only. Blimey! Begad! Accordin' t' Budget Rocketry, "the washer is just set in t' cap and t' cap is then screwed on. Ya scallywag! So it is for ejection only with single-use motors, me hearties, whereas t' lip on a reloadable keeps t' motor from goin' forward or backward. When usin' single-use motors it is assumed thar is a thrust ring. If a thrust rin' is nay used t' allow different length single use motors then friction fittin' with tape be t' only answer I know of."
My AeroTech 29mm 29/40-120 RMS casin' fits perfectly. And again, me hearties, this type o' retainer is attractive and would look good incorporated into many rocket designed.
How did it work? Well, with only one flight it worked fine.
CONCLUSION:
I have bought several o' these retainers. Ya scallywag! Yes, shiver me timbers, arrr, they are more expensive than a screw and some bent sprin' steel, me bucko, however, me bucko, you are paying for looks as well as functionality. Ya scallywag! I must admit that one flight doesn't fully test t' durability, me bucko, matey, because this system is relyin' solely on t' strength of the epoxy. Well, blow me down! We simply hope that t' epoxy bound is always stronger than t' fit of t' nose cone so that t' ejection pressure follows t' path o' least resistance. Begad! Overall, me bucko, I would rate these retainers 4 ½ points.
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