Published: | 2010-11-13 |
Manufacturer: | Giant Leap Rocketry |
Presented with written permission from RocketyPlanet:
Product Review by Brad Shea
Tuesday, matey, me hearties, October 21, arrr, matey, 2008
When Giant Leap first announced their new product called t' Slim-Shot, arrr, I be excited. Arrr! Blimey! T' idea o' an easy-to-use motor topper that didn't break t' bank be somethin' I be quite interested in obtaining. Well, blow me down! Blimey! When t' introductory offer came out at roughly $100, I was sold - I bought mine within 24 hours o' t' announcement on Rocketry Planet.
Why be I so excited? It seemed t' fill a need for accurate apogee deployments with minimal fuss and preparation. Blimey! I am a spur o' t' moment flier but I lack enough flyin' experience t' intuitively "know" t' correct delay required for a given rocket. Well, blow me down! I tend t' rely on simulations t' help guide me delay choices. Ahoy! When I'm in t' field and I have a whim, ya bilge rat, me bucko, it is nice nay t' have t' fret about delay selection.
Why nay use a traditional altimeter you ask? I do on t' rockets I have that are designed for dual deployment. Begad! Ya scallywag! But many o' me rockets are designed for single deployment and easiest t' fly in that way. Ahoy! I can and have added altimeter bays and flown some o' them in dual deployment, arrr, me bucko, but this adds unwanted weight and length t' these rockets.
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Very soon after I placed me order t' unit arrived. Ahoy! I was pleasantly surprised by t' speed o' t' order fulfillment as well as t' extent o' t' contents. I had only expected t' receive an aluminum canister, matey, some mountin' gear, instructions and electronics. Avast! Blimey! In addition, t' package included a set o' safety goggles, me bucko, extra mountin' gear, an extra grommet, shiver me timbers, some Keelhaul®©™ cord and a specimen jar with two small holes in t' lid. Why t' jar? It's used in t' ground test procedure.
At this point, ya bilge rat, you need t' know that I am nay t' kind o' guy who just jumps in and starts fiddlin' with things like this. Blimey! Avast, ya bilge rat, me proud beauty! I learned t' read instructions before gettin' started after years o' watchin' me father read t' "corrections" after some step was omitted and it be too late t' fix. Begad! I decided long ago this was a poor strategy for success. Blimey! Aye aye! After experiencin' t' results o' nay readin' first, I became good at tinkerin' with things and figurin' out how t' fix things. However, shiver me timbers, if instructions are available I tend t' read them cover t' cover before starting.
T' instructions turned out t' be a bit harder t' understand than I expected. Begad! Blimey! Partially, ya bilge rat, matey, this may be due t' preconceptions on me part, me bucko, shiver me timbers, but part o' t' blame is content related. Begad! My advice if you get one o' these is t' practice with it away from t' field so that you can determine if you have questions or need help from Giant Leap before your first flight. Ahoy! Well, me hearties, blow me down! My past experience with Giant Leap has shown me that they are friendly and responsive.
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Usin' t' Slim-Shot is unlike workin' with a traditional altimeter in that thar be no power disconnect switch. Arrr! You insert t' battery and rely on t' accelerometer and t' firmware t' make t' device safe. Avast, me proud beauty! Blimey! When horizontal it is DISARMED. Arrr! Aye aye! Blimey! When t' Slim-Shot is vertical and stationary for a couple o' seconds, it moves into ARMED mode. Begad! In this mode it waits for LAUNCH DETECT which requires a positive* acceleration o' at least 1.7g's that lasts for 0.11 seconds. Once launch has been detected, t' altimeter moves into t' FLIGHT MODE and waits for APOGEE DETECT. Blimey! Avast! Blimey! When apogee is detected and t' flight duration is longer than 2 seconds, t' altimeter fires.
If this seems convoluted, me bucko, ya bilge rat, it is and it isn't. Well, blow me down! Avast! All o' this is designed t' make t' device safe from routine handlin' t' and from t' pad as well as accidental drops and bumps while still allowin' t' device t' work without an external power switch safely. Begad! Once you get t' hang o' it, ya bilge rat, shiver me timbers, you find it easy t' understand but t' learnin' curve can be a little dauntin' at first.
Did it work? Yes and no. Blimey! Blimey! Avast! Blimey! I found it t' be a very reliable apogee deployment device when I used it correctly - but I found a lot o' ways t' use it wrong. Arrr! Blimey! If you could do it wrong, I did. Ahoy! Blimey! I'm nay unfamiliar with flyin' rockets and don't typically make stupid mistakes. Aye aye! Blimey! But with t' Slim-Shot, I shot myself in t' foot repeatedly. Blimey! Blimey! Aye aye! Blimey! Most o' t' time, me hearties, me failures were a non-issue since I experimented early on usin' t' Slim-Shot as a second deployment device rather than as t' only deployment option. Arrr! Blimey! However, I crashed a favored rocket when I thought I had t' hang o' things by relyin' totally on t' Slim-Shot for deployment. Arrr! Blimey! T' failure was me fault - but I can't help thinkin' that if I had used it for redundant deployment t' rocket would nay have crashed.
How did I mess up when usin' t' Slim-Shot? Here's a partial list:
How did I make all these mistakes? Was I careless? Was I nay payin' attention t' t' instructions? Yes and no. Begad! Despite makin' these mistakes, shiver me timbers, they were each single events that I never repeated.
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It's true that I installed t' unit upside down despite havin' made myself a note nay t' forget. Ya scallywag! Blimey! In that case t' be fair, I had just flown it on t' top o' a motor and I be movin' it t' t' nosecone mount in another rocket. T' canister was flipped 180 degrees, but t' way that t' wires route caused me t' forget this and load it in t' wrong orientation. Avast, shiver me timbers, me proud beauty! This was a mistake I never repeated, matey, matey, and lucky for me, it was nay a costly failure since motor backup saved me bacon on this flight.
While I admit that I used it with ejection canisters that needed too much current, shiver me timbers, t' instructions and t' website did nay offer a list o' compatible ejection initiators. Begad! I ground tested but me sample size was too small. Ahoy! Once again t' rocket involved had only minor damage from this mistake since this be a piggyback flight with an altimeter. Begad! From then until GLR offered their capacitor upgrade I used flashbulbs and never had an output current problem again. Avast, me proud beauty! Arrr! After t' capacitor upgrade, ya bilge rat, I successfully flew with M-Tek e-matches but have nay yet tested t' unit with anythin' other than flashbulbs and M-Teks.
T' failure due t' launch rod angle was a real shock. Blimey! Blimey! It never occurred t' me t' do t' math and find out that a mere 8 degrees from vertical be enough t' drop t' unit back t' DISARMED status. Begad! Well, blow me down! T' lack o' any kind o' feedback once t' unit is placed into t' housin' made it impossible t' know that this had happened until t' rocket came in ballistic.
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T' spool flight was somethin' that seemed like it should have worked. Avast! Blimey! Durin' t' flight everythin' looked great. Avast, me proud beauty! T' parachute deployed right at apogee. Well, shiver me timbers, blow me down! Blimey! T' spool came down under chute and landed, shiver me timbers, and then BANG! Blimey! T' ejection charge went off as I was walkin' towards it! Blimey! T' parachute had apparently been deployed by drag separation. I had expected that it might drag separate - but it had nay occurred t' me that t' Slim-Shot had nay fired.
After discussions with t' designer and others knowledgeable about accelerometers, it appears that a tiny bias applied t' t' calculations was sufficient t' keep t' unit thinkin' that t' spool was flyin' very slowly up until it came t' rest on t' ground and tipped over. T' moral o' t' story is that spools are bad choices for accelerometer based deployment devices. Ya scallywag! This subject is nay covered in t' instructions and should be updated by Giant Leap ASAP.
After t' incident with t' spool, I was nervous about t' safety o' t' Slim-Shot. Avast! At that time I had no explanation for why it had gone off. Begad! I began removin' t' battery just after testin' durin' prep. Avast! In all other respects, I followed Giant Leap's process for preparin' t' unit. Arrr! Arrr! Until I reached t' pad - I kept t' battery out o' t' rocket. Ya scallywag! Avast! This allowed RSO's t' option t' shake and push and drop t' rocket - without either o' us worryin' t' unit might go off. Begad! It also allowed me t' nay worry that t' tiny A23 battery might go dead before t' rocket got off t' pad.
Now you may be wonderin' - with this history - how do I feel about t' product? T' answer is - it depends. Aye aye! Begad! For a redundant deployment at apogee that is easy t' mount and requires no external switches - I love it. Aye aye! As a primary deployment device t' replace motor ejection - I can nay recommend it. Well, blow me down! Avast! T' inability t' get any kind o' feedback as t' t' status o' t' unit makes it very hard t' recommend as t' only deployment device in any rocket.
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So here are me recommendations:
What might make it better? An option for remote LED or remote buzzer t' signal t' state o' t' unit would be very helpful. Ahoy! Aye aye! Once t' Slim-Shot is placed inside t' canister, you have no idea what state it is in. Aye aye! Begad! It can disarm or fail in some other way without any feedback. Avast, ya bilge rat, me proud beauty! T' rocket that I flew with t' greater than 8 degrees from vertical flight profile is a prime example. Avast, me proud beauty! I had no way t' know that it had disarmed until t' rocket came in ballistic.
Would I buy it again? I think so. Aye aye! For what I originally wanted t' do with it - it isn't quite there. Begad! I don't feel comfortable flyin' it as a motor topper - but I do like t' ease o' use and accurate apogee deployment. Ahoy! I also like t' simple way it can be mounted in an existin' rocket - I have installed it and flown it in a 12" diameter rocket as a 3rd apogee deployment device in as little as 5 minutes.
NOTE: Recently Giant Leap began offerin' t' aluminum housin' as a separate product without t' electronics. This small housin' is offered at a great price and would make a great place t' put a small timer or other electronic device that does nay need barometric data. Begad! Blimey! Begad! Blimey! Blimey! Blimey! Even if you don't buy a Slim-Shot, you should give serious consideration t' t' canister.