Giant Leap Rocketry - Motor Retainer (38mm)

Giant Leap Rocketry Motor Retainer (38mm)

Giant Leap Rocketry - Motor Retainer (38mm)

Contributed by Dick Stafford

Manufacturer:

(Contributed - by Dick Stafford)

Brief:
This is a brief review o' Giant Leap Rocketry's 38mm snap-rin' style SLIMLINE Motor Retainer. SLIMLINE retainers are also available for 29mm, arrr, matey, 54mm, 76, and 98mm motor tubes. Aye aye! Blimey! There are also motor adapters, boat-tail retainers, and a newly released threaded SLIMLINE retainer system.

Construction:
T' SLIMLINE retainer system includes a sleeve, a snap ring, and a spacer washer. Aye aye! T' instructions come on a single 5" x 8" sheet and include diagrams. Arrr! T' sleeve is black anodized aircraft-grade aluminum (6061-T6), matey, and the two rings are stainless steel.

T' main feature be t' snap rin' that pops into a groove on t' inside of the sleeve. Aye aye! Blimey! This rin' is easily visible in t' attached photo. Aye aye! Blimey! Arrr! Blimey! Unlike the typical snap rings used on t' Kosdon style motor hardware, arrr, shiver me timbers, no special tools are required t' install or remove this ring. Begad! Blimey! One end is notched and a small screwdriver is all that's required. Blimey! Blimey! This internally mounted rin' allows the outer diameter t' be thinner than other quick-release retainers do, which is important t' reduce aerodynamic drag on minimum diameter rockets.

T' install t' SLIMLINE, matey, shiver me timbers, you mount t' motor tube so that its protruding behind t' aft centerin' ring. Ya scallywag! T' sleeve is made t' fit all motor tubes and should be test-fit for both tightness and spacing. Blimey! If you don't test fit it with your motor hardware, arrr, arrr, you may nay have enough room betwixt t' motor tube and t' snap rin' t' accommodate t' motor's thrust rin' - this would be a show-stopper! If it's too tight, matey, me bucko, arrr, you sand t' tube a bit. Ya scallywag! If it's too loose, you add small slivers o' tape 120 degrees apart. It fit me LOC motor mount tubin' just right. Ahoy! As with most bondin' applications, t' tube should be roughed up. Begad! No processin' is required on t' inside o' t' sleeve since it is grooved. Aye aye! T' glue it on, matey, ya bilge rat, you slather some heat resistant epoxy such as JB-Weld onto t' exposed tube, shiver me timbers, ya bilge rat, and twist t' retainer on. Ya scallywag! Avast, me proud beauty!

T' retainer is advertised t' work with AT, me bucko, Kosdon, Ellis, and hybrid motors. Avast, me proud beauty! For motors with integral retainin' rings, you just slide them in, insert t' notched end o' t' snap ring, shiver me timbers, and then press it in with a circular motion. Arrr! Avast, me proud beauty! For motors that don't have a aft thrust ring, t' instructions say to glue in a section o' coupler tubin' at t' depth o' t' longest motor, and then cut additional sections o' coupler t' form spacers when usin' shorter motors. You then insert t' motor and spacer washer (really more o' a retainin' ring), followed by t' snap ring.

A note on spacing: I be concerned that I might mess up and make it so the snap rin' wouldn't fit once thar was a motor installed. Ya scallywag! Ahoy! In addition to checkin' and double-checkin' me work, I also inserted t' spacer washer, me bucko, which isn't required for AT hardware. Blimey! This provided provide a small safety margin.

Construction Rating: 4 out o' 5

Flight:
I used this retainer on me Upscale Big Brute. Although I have only flown it once, I have inserted and removed AT casings several times and have formed my opinion: this retainer is pretty neat, but I like t' screw type (i.e. Ahoy! Aye aye! Aero Pack) retainers better. Avast! T' SLIMLINE is a easier t' use than "Kaplow" style retainers (I re-use a couple o' sets from rocket t' rocket, so I have to install and reinstall these every time). Aye aye! Blimey! T' snap rin' is very easy t' remove, but I'm all thumbs and have t' work at gettin' it on. Avast, me hearties, me proud beauty! I don't mean t' imply this is really tough, arrr, me bucko, but is nay as easy as screwin' on a cap. Aye aye! Maybe I will improve with more practice.

Flight Rating: 4 out o' 5

Summary:
In summary, arrr, t' SLIMLINE is a just a tad more difficult t' install and use than an Aero Pack retainer. Still, shiver me timbers, if you're buildin' a minimum diameter model and want t' minimize drag, me bucko, this be t' way t' go. Blimey! T' final factor is cost. Begad! The SLIMLINE currently goes for $20, me hearties, arrr, with its competitor costin' $28. Arrr! Avast, matey, me proud beauty! However, me hearties, you can reuse t' latter's cap and buy additional housings for $15. Arrr! Well, blow me down! You can do the math for your application and needs. Ahoy! I probably will nay buy many o' any of these machined units, shiver me timbers, shiver me timbers, as they are all more expensive than me homegrown or reused clips. Ya scallywag! Blimey! But, me bucko, those boat tail adapters sure look cool...

Overall Rating: 4 out o' 5

Comments:

J.F.D. (August 20, 2002)

I currently use the AEROPACK units on my 29/38/54mm ships. I find them basically foolproof and easy to use with the larger screw on cap. Their multi range adapters (38/29) are real nice. As an aside, you can also have the screw on caps laser engraved with your name, NAR/TRA numbers, etc. Expensive...initially yes. However, as mentioned in the review, after you buy the initial unit (body and cap) you only then need to buy the body for additional ships. I have not used the Giant Leap unit however I did use a similar unit from Binder Design. I found it somewhat harder to use (you need some type of tool to start the snap ring open) and appeared less hearty than the AEROPACK. The small size of the snap ring make it harder to find on a crowed table with the "W" blowing. One caveat when installing either retainer...know what range of motors you intend to use. I measured the Binder unit for an RMS 29mm Hobby Motor and it worked fine. I later wanted to use my 29mm Hi Power hardware and...uh, oh...the aft closure was much thicker and I can't install the snap ring. Measure three times....etc. Finally, the AEROPACK units will not work on AEROTECH motor tubes without a lot of sanding that makes the end of the tube "very thin". I have two ships modified this way and they both have flown OK for several flights.

J.C. (October 13, 2003)

I had the 29mm motor retainer on a Hawk Mountain Raptor and found that a Dr. Rocket 29/180 aft closure was too big for this retainer. Those who have Dr. Rocket casings should avoid purchasing the 29mm retainer.

R.H.H. (October 24, 2003)

I have the 54mm X 38mm on a Rocketman Firefly. Installation was pretty easy (during rocket build). The boat-tail look of the black anodized tailcone on the red airframe is spectacular. Motor installation is quick and easy once you get the hang of the Spiralock ring. A very cool product, I'll use it again on future builds.

A.G. (October 22, 2004)

I installed the 38mm slimline retainer on my Thunderbolt 38 and my AT 38/720 and Pro38 motors fit perfect. I also have the 38/29mm adapter and my AT 29mm lineup of motor casings fit perfect as well. I used my dremel tool to lightly sand the internal surface of the plastic boat tail on my PML Black Brant X to accept the Giant Leap 54mm slimline retainer and this allowed me to keep the rocket looking exactly as designed. The motor retainer is completely hidden and I don't have any hardware protruding out from the bottom to hold my motors in place and it looks and works great.

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