Giant Leap Rocketry Crossbow

Giant Leap Rocketry - Crossbow {Kit}

Contributed by Darrell Mobley

Published: 2010-11-13
Manufacturer: Giant Leap Rocketry

Visit RocketryPlanet for the latest Rocketry News
Presented with written permission from RocketyPlanet:

Product Review by Darrell D. Mobley
Thursday, matey, December 18, 2008

Kit
T' Crossbow comes with a whole box full o' goodies, me bucko, and promised t' be a lot o' fun.

Recently, matey, I had t' opportunity t' get me hands on Giant Leap's new Crossbow, shiver me timbers, a 4" diameter rocket with what looks like a Talon-inspired theme. Aye aye! In reality, matey, shiver me timbers, t' Crossbow is more akin t' its cousin, arrr, t' Nuclear Sledgehammer, arrr, with three fins plus a pair o' mini-wings and forward canards.

At any rate, t' Crossbow looked liked somethin' I would enjoy buildin' and I was happy t' get me hands on this kit. Well, blow me down! In September, me bucko, me bucko, t' UPS man arrived and I was off t' t' shop.

T' Crossbow comes standard as a 55-inch long kit carryin' a 54mm motor mount with a dry weight o' four pounds, and t' list o' standard features makes it well worth t' price. Ya scallywag! Standard on t' kit is:

  • Pre-slotted phenolic airframes
  • 5-to-1 Pinnacle nose cones and tail cone
  • Keelhaul®©™ recovery harness protector sleeve
  • Keelhaul®©™ parachute protector
  • Slimline 54mm motor retainer
  • Dual ACME rail guides
  • 48" Spherachutes parachute
  • Pre-sewn nylon shock cord
  • G-10 fins, ya bilge rat, wings canards
  • All necessary hardware
  • Crossbow decal

Also available are a number o' upgrades, me bucko, includin' a dual deployment option which includes an avionics bay, an additional shock cord, a drogue parachute, all mountin' hardware, and a 24" phenolic payload airframe; as well as a Dyna-Wind single or dual deployment version; along with several recovery options and an optional 38mm-to-54mm motor adapter t' fly t' Crossbow on 38mm motors.

Alignment
T' variety o' jig and templates I came up with helped get t' fins on straight.
Alignment
After t' fins were in place and t' airframe attached, me hearties, ya bilge rat, it was time t' fillet t' fin joints. Begad!
TTW
T' Crossbow really has a sexy shape t' it, with all those fins and wings.
Tube
T' forward canards were moved from t' main airframe tube onto t' payload bay tube. Avast!

Recommended motors are 38mm and 54mm I and J motors - t' standard single deployment Crossbow comes with a warnin' nay t' exceed a specified motor size (an AeroTech 54/852 motor or equivalent) without addin' additional nose weight t' increase stability. T' kit includes lead shot t' put in t' nose cone, but Giant Leap recommends addin' more if you want t' fly larger motors. Ahoy! Blimey! My recommendation is t' get t' dual deployment option and eliminate t' issue, ya bilge rat, which is what I did, arrr, ya bilge rat, as additional nose weight isn't needed in t' longer dual deployment version - it is plenty stable due t' t' increased length.

One o' t' first things I did after openin' t' box and fondlin' all o' t' parts was t' get right into t' directions and read them from cover-to-cover. Arrr! Blimey! Somethin' that has always impressed me with Giant Leap kits was t' extremely thorough, shiver me timbers, well illustrated, instructions that comes with their kits. But I have a known aversion t' leavin' well enough alone and wanted t' see what be in store for me in t' days ahead.

Because o' t' tail cone and t' number o' fins, I had a little apprehension about makin' sure t' fins were well attached, so I studied this part o' t' instructions really well, me hearties, while dry-fittin' t' parts and seein' if thar were areas I could make adjustments t' achieve a better end result. Begad! I have t' tell you, me bucko, arrr, I actually cringed when I saw t' illustration o' a perfectly good Slimline retainer gettin' roughed up and covered with JB-Weld! I have always been a proponent o' installin' t' beautifully anodized motor retainers after t' rocket be painted, shiver me timbers, as an accent t' t' finish, shiver me timbers, and gluin' it into t' rocket right off t' bat went against me grain. Somehow though, I knew I would figure somethin' out.

That is nay t' say you shouldn't follow t' instructions, arrr, arrr, this is just a quirk o' me own. Blimey! Followin' t' instructions will give you excellent results that you will be extremely satisfied with. What I propose t' do here, me bucko, though, is give you an alternative method if you would like it, and then you could decide which way you liked best and apply it t' your own build.

T' instructions call for attachin' t' Slimline retainer t' t' motor mount tube, attachin' t' forward pair o' centerin' rings, ya bilge rat, installin' t' motor mount tube in t' tail cone and mountin' all o' that t' t' airframe before attachin' t' fins. Avast, matey, me proud beauty! Blimey! That's a lot t' accomplish in a short amount o' time and t' instructions expressed due concern about gettin' it all just right. Aye aye! Blimey! Blimey! Blimey! In me mind this would also require me t' have great faith in me fin-tab-to-motor-mount-tube epoxy joints, ya bilge rat, matey, and with t' motor mount tube completely enclosed in t' tail cone, arrr, thar be no way I could get inside t' fillet t' joints. Ahoy! Blimey! Without knowin' it, arrr, I had encountered what Kent from Giant Leap later described succinctly as t' "Talon Syndrome."

So I created an alternative tail cone assembly process and submitted a copy t' Giant Leap for future use if they so desire, arrr, and I will describe that assembly process here for you t' use, ya bilge rat, too, me hearties, me bucko, if you like. My process allows you t' build t' motor mount tube, install it into t' tail cone, ya bilge rat, then install t' fins before installin' t' forward centerin' rings, all in individual steps rather than one quick step. Begad! Ahoy! In doin' it this way, you can fillet t' fin tab joint where they meet t' motor mount tube.

You can also optionally decide with this process, as I did, me bucko, arrr, t' foam t' inside o' t' fin can after t' fins are installed and filleted. I did this because, me bucko, arrr, in me thought process, arrr, t' foam would add a stable backin' at t' fin-to-tail-cone joints, and prevent t' fins from potentially separatin' from t' tail cone if t' tail cone were ever depressed inward around t' fins.

On t' forward end o' t' tail cone, t' motor mount tube is centered in t' 4" openin' by a pair o' 54mm birch plywood centerin' rings. Ahoy! T' length o' t' motor mount tube is based on t' length o' t' tail cone, matey, t' shoulder o' t' tail cone, t' thickness o' t' two centerin' rings and t' placement o' t' Slimline retainer flush with t' aft end o' t' tail cone.

Inserted
When I lined up t' holes for t' electronics sled, ya bilge rat, t' bulk plate disks were off center. Ahoy! When I centered them, ya bilge rat, t' holes didn't line up. Ya scallywag! What t' do?
Bulkhead
When inserted t' t' eyebolts into t' electronics bay end caps, t' eyebolts were too short if I used a nut and washer on each side. Avast! What do do?
Bulkhead
Rotatin' t' end cap bulk plate disks 90 degrees and recessin' t' washer holes worked out great.

Recessin' t' washer holes really made a lot o' sense when I saw how well they turned out.
Bulkhead
T' removable electronics sled sits snuggly betwixt t' two end caps.
Inserted
My "receiver hitch," which holds t' electronics bay into t' payload section. Avast! T' all-thread screws into t' two T-nuts, t' "keyhole" clears t' main chute ejection charge, t' recovery harness passes through t' middle. Avast, me proud beauty!

I replaced t' rear-most o' t' two forward centerin' rings, ya bilge rat, which are standard 4-inch-tube-to-54mm rings, with a 4-inch-coupler-tube-to-54mm ring. I did this so I could make a "stepped" forward centerin' ring, matey, slippin' it in place, dry, while I attached t' fins. Ahoy! Ahoy! Then I could remove it and fillet me fin joints, and then epoxy it in place permanently when t' fins and tail cone assembly was complete.

In t' kit, t' Slimline retainer basically forms t' aft centerin' ring, because t' tail cone tapers right down t' t' outside diameter o' t' motor retainer. Begad! Ahoy! But because I wanted t' install t' Slimline after paint, shiver me timbers, matey, I decided t' put an additional centerin' rin' at t' aft edge o' t' three rear-most fins, shiver me timbers, t' allow me t' leave t' Slimline out until it be completed. Avast! And, because I had made one o' t' forward centerin' rings so that it fit inside t' tail cone with me stepped design, arrr, I took advantage o' this additional 1/4" o' motor mount tube length t' move me Slimline retainer out o' t' tail cone by that same distance. Arrr! So rather than sittin' flush, ya bilge rat, me retainer hangs out t' back a little bit, arrr, which I hoped would reduce t' potential for t' motor's flame t' toast t' aft o' t' tail cone's finish.

Here's how I did it: I cut a 2-7/8" centerin' rin' from 1/4" birch plywood with a 54mm motor mount hole in it. Begad! T' centerin' ring's outer circumference was tapered t' fit t' inside curvature o' t' tail cone and was designed t' mount flush with t' openin' o' t' three tail cone fin slots. Avast, me proud beauty! For me application, this centerin' rin' be mounted with 15 minute epoxy 1-5/8" up from t' aft edge o' t' motor mount tube. Ahoy! In this manner, t' fins butted up against t' centerin' ring. Blimey! Well, blow me down! Your measurement may be different, so measure twice, glue once.

I cut a 1/4" birch centerin' rin' with a 54mm motor mount hole in it that would fit inside t' forward openin' o' t' Pinnacle tail cone. Ya scallywag! Avast! You could use a regular 4" coupler bulkhead plate, but t' Pinnacle tail cone's shoulder is thicker than a phenolic coupler, so you would have t' sand it down some and then cut a 54mm hole in it.

This new centerin' rin' be epoxied t' one o' t' original forward centerin' rings. Avast, ya bilge rat, me proud beauty! Blimey! No matter which way you build your Crossbow, me bucko, make sure t' check t' see if your eyebolt/nut/washer combination clears t' tail cone. Aye aye! Blimey! I noticed mine be hittin' and had t' grind an area out so it would sit flush and nay push t' tail cone shoulder out o' round.

With t' epoxy on both parts dry, I roughed up t' inside o' t' aft end o' t' tail cone where me new centerin' rin' would contact t' cone with 80 grit sandpaper. Arrr! Well, blow me down! I also sanded t' motor mount tube where t' Slimline would be placed and where t' fins would mount. A liberal amount o' epoxy be applied t' both t' inside o' t' tail cone where it met t' aft centerin' rin' and around t' circumference o' t' aft centerin' ring. Blimey! Arrr! T' motor mount tube is slid into place, t' forward "stepped" centerin' rin' is slid on t' temporarily into hold t' motor mount tube in t' proper position and t' assembly is allowed t' dry.

Once dry, me hearties, and without takin' t' forward centerin' rin' off, me hearties, it be time t' mount t' fins. Well, blow me down! Blimey! I used some additional 54mm phenolic couplers and motor mount tubin' I had layin' around t' extend t' motor mount tube temporarily, givin' me a method t' position t' tail cone assembly horizontally where I could attach t' fins. Begad! Blimey! I wanted t' mock-up t' be as close t' level as possible t' help me align t' fins better.

I used a pair o' "V" blocks I had built t' lay this in, which would let me rotate t' tail cone as I installed t' fins. Combined with additional jigs cut from luaun door skin plywood t' properly position t' fins at t' right angles, matey, me tail cone looked like a contortionist's day dream when t' fins and jigs were in place. Aye aye! Blimey! T' bottom line is if you take you time and use your head, you can come up with t' means t' get your fins in t' right places.

Once t' fins were dry, I removed t' forward centerin' rin' which be temporarily holdin' t' motor mount tube in t' centered position. Avast, arrr, me proud beauty! I mixed up one or two squirt o' West Systems 105 epoxy and hardener and poured it into t' tail cone. Ahoy! I then spent about 10 minutes rotatin' and rollin' t' tail cone around t' distribute t' epoxy all along each fin's intersection with t' motor mount tube and t' tail cone. Well, blow me down! I kept this up until it started t' gel and then repeated t' process again, matey, shiver me timbers, makin' sure I had great coverage. I now felt very good about t' fin-to-motor-mount joints.

My next step was t' fill t' area with two-part urethane foam. Blimey! Giant Leap sells a version o' this that would be a perfect fit here. Ahoy! After t' foam was cured, I installed t' forward centerin' rin' for t' final time, but nay before I drilled t' necessary hole for t' recovery attachment point and bolted it securely into place.

To finish t' airframe assembly, all I had t' do was epoxy t' airframe tubin' t' t' tail cone assembly and admire me work. Avast! Blimey! Somethin' that jumped out at me be that with t' dual deployment option, arrr, t' rocket's perspective with regard t' t' forward canards was askew. Ahoy! Blimey! On t' standard rocket without dual deployment, t' canards are mounted on t' main airframe, right below t' nose cone. Arrr! With t' dual deployment option, me hearties, t' 24 extra inches o' airframe that makes up t' main recovery area, me bucko, or payload bay, me bucko, me bucko, makes t' canards looks orphaned "way back there."

So, I "fixed" it - I epoxied up t' canard slots in t' main airframe and cut new ones at t' base o' t' main chute compartment, shiver me timbers, placin' t' canards right above where t' rocket splits at apogee. Ahoy! I thought it looked a lot better this way for t' dual deployment version and is a simple change if you want t' do yours that way. Because o' t' canards bein' mounted in t' area, me bucko, me bucko, where t' coupler that would be housin' t' dual deployment avionics bay is located, I opted t' mount t' canards by tapin' t' inside o' t' slots and slidin' a coupler in place t' support t' canards until t' epoxy set. Begad! If you want t' move your canards and don't use a removeable electronics bay setup, matey, you can glue in your coupler and then glue t' canards in place.

Finish
T' Crossbow turned out just great, and t' red and black accents certainly work well with t' Chrome Yellow paint. Arrr! Blimey!
Finish
Red and black self-adhesive Monokote simplifies t' addition o' trim accents, matey, ya bilge rat, and t' colors work well together. Avast, me proud beauty! Ya scallywag!
Finish
This closeup shows t' extended Slimline retainer peekin' out from t' rear, as well as t' great lines o' t' fins. Avast, me proud beauty! Aye aye!

Some o' you observant readers may notice that me bare airframe shots look like t' tubes have fiberglass on them. Good catch! I have gotten too old t' enjoy airframe repairs after completin' a rocket, and I have found that fiberglassin' t' airframes be t' best insurance against this. Avast! I could have gotten t' Dyna-Wind version, me hearties, and highly recommend it for those who want t' additional strength without resortin' t' doin' it yourself, but I opted t' glass me tubes myself. I did this before startin' construction, usin' one layer o' fiberglass sleevin' and turnin' t' tubes on a wood lathe t' sand them smooth. Just remember, fiberglassin' will add t' t' overall weight, me bucko, so you have t' choose motor accordingly.

With t' airframe assembly completed, me next step was t' fillet all t' external fin joints. Blimey! Blimey! T' additional fins meant a couple o' extra steps but t' end result be startin' t' materialize from this box o' parts, shiver me timbers, and I be likin' what I be seeing. It be time t' concentrate on me avionics bay, arrr, since I had t' dual deployment option and I would use Giant Leap's dual deployment kit t' build one o' me standard electronics bay designs.

With t' dual deployment version, you get all o' t' necessary hardware t' create a nice avionics bay. Begad! T' 4" version uses very stout 1/4"-20 threaded rods, .062" G-10 for t' altimeter mount, shiver me timbers, ya bilge rat, and dual 1/4" end caps that make up a solid 1/2" thick cap for each end. One thin' I noticed however be that t' end caps seemed t' have mismatched holes in them - if I matched up t' holes, ya bilge rat, t' inner cap wasn't centered on t' outer cap. Blimey! If I centered t' inner cap on t' outer cap, t' holes wouldn't line up. Aye aye! Arrr! T' center hole would line up, me bucko, but t' holes for t' electronics sled didn't. Ya scallywag! What t' do?

My solution: I just rotated t' holes 90 degrees, applied epoxy, centered t' inner cap over t' outer cap and bolted it together with a 1/4"-20 bolt in t' center hole until dry. I then could redrill me electronics sled holes and go on.

Another thin' I noticed was that if I put a nut and washer on t' eyebolt and stuck it through t' end cap, shiver me timbers, thar wasn't enough room for a washer and nut on t' other side. Aye aye! I couldn't do without t' washers, me bucko, which help spread t' load o' t' recovery event, so what t' do?

My solution: I took a couple o' flat-bottomed spade bits, me hearties, one t' diameter o' a regular 1/4" flat washer and t' other t' diameter o' a 1/4" fender washer, and used them t' recess t' holes in t' center o' t' end caps by t' thickness o' t' washers. Arrr! Blimey! Avast, me proud beauty! Blimey! T' result be a flush mounted washer on both sides, me hearties, a cleaner solution that doesn't protrude into t' electronics bay area. Avast, me proud beauty! Blimey! I was very happy with t' solution.

T' dual deployment kit comes with a regular coupler, which is about 1/2" longer than t' supplied G-10 electronics mountin' board even when you take into consideration that t' end caps protrude into t' electronics bay 1/4" on each end. I do nay prefer a 1/2" o' slack in me electronics bays, ya bilge rat, ya bilge rat, shiver me timbers, as I do nay want me electronics bein' able t' bang around. Avast! Blimey! I like them mounted securely with little movement.

Electronics
T' removable electronics bay allows for easy access t' t' electronics inside.
Electronics
With t' hood up, you can see t' Cannonball Works RRC2-Mini and quick disconnect for t' drogue charge.
Electronics
On t' back side, t' Newton's 3rd 9V battery holder is easy t' get to, shiver me timbers, matey, me hearties, t' main charge holder tube in t' upper left. Arrr!
Electronics
T' ability t' take it all t' way apart makes access easy and service simple.
Electronics
T' "receiver hitch" is what holds it all together. Begad!

In me design, t' G-10 mountin' board runs from one end cap t' t' other, and I cut down t' coupler tube t' make it t' length t' fit this space. Well, blow me down! Blimey! T' piece o' coupler tube I cut off be then used t' make a "receiver hitch" which is mounted permanently in t' payload tube.

I replaced t' short brass tubes that come in t' dual deployment kit that are used t' mount t' electronics mountin' board with carbon fiber arrow shafts. Well, blow me down! My new tubes extend 1/4" longer than t' G-10 mountin' board on each end. Begad! This allows them t' be fitted into t' inner end cap bulk plate on each end, addin' strength t' a collapsible design that comes completely apart. Ya scallywag! Begad! So where you see t' black carbon fiber tubes in t' accompanyin' photos, shiver me timbers, they extend halfway through each end cap - t' holes in t' end caps are sized accordingly, me hearties, larger on t' inside, me bucko, smaller on t' outside. Ya scallywag! Avast, me proud beauty! I attach t' G-10 t' t' carbon fiber tunes with medium CA, me hearties, full length, both sides. Arrr! T' tubes or G-10 are nay glued t' either end cap.

T' "receiver hitch" is made by cuttin' a 4" coupler tube bulkhead plate, addin' a 29mm hole in t' center. T' this is added two holes which correspond with t' holes in t' electronics bay end caps. Aye aye! Blimey! These holes will have two 1/4"-20 T-nuts inserted that t' electronics bay all-thread will screw into.

This bulk plate is epoxied into t' cut-off piece o' coupler tube previously mentioned and will mount permanently inside t' payload tube, t' receive and hold t' electronics bay. Before doin' that, a "keyhole" recess is cut t' one side o' t' 29mm center hole, as shown in t' accompanyin' photos, t' clear t' main ejection charge holder tube, which mounts in t' forward end cap.

I make me ejection charges for this rocket out o' 1/2" launch lugs housin' flash bulbs. T' main ejection charge holder tube is a 3" long piece o' 3/4" aluminum tubing, matey, 1/16" wall, me bucko, with a 1/4" thick plywood aft plug, epoxied into t' "back" side o' t' forward electronics bay end cap. Avast! T' "back" side is identified as t' side opposite o' t' carbon fiber tubes, me hearties, and is pointed out in an accompanyin' photo. Begad! Avast, me proud beauty! T' "front" side has an aluminum bracket fashioned from 1-1/4" wide, me bucko, shiver me timbers, 1/16" wall, arrr, me bucko, aluminum strap and holds t' altimeter switch. Arrr! T' opposite end 0cap used a regular electronics terminal wired through t' cap t' connect t' t' drogue ejection charge.

Access t' t' electronics bay power switch is through a 1/4" vent hole, arrr, which is placed directly over t' switch. Begad! Blimey! Careful measurin' and drillin' will put your holes in t' correct places. Another matchin' 1/4" vent hole is placed 180 degrees on t' aft o' t' payload compartment.

For recovery, I would be usin' t' new Cannonball Works RRC2-Mini, me bucko, a wonderfully simple t' use altimeter with a small foot print. Housin' t' 9 volt battery that powers t' altimeter is a Newton's 3rd 9V battery holder. Begad! I like this holder because it sits up off t' backin' plate, which allows you t' slip a nylon wire zip-tie under and around t' battery t' secure it in place.

Field assembly o' t' electronics bay is a snap, access is wide open, me hearties, me hearties, and you can replace any o' t' parts without havin' t' majorly rebuild any part o' your electronics bay. That is what I like about this design. Well, blow me down! No hatches, ya bilge rat, doors, me hearties, external switches, ya bilge rat, screws, etc., arrr, me bucko, are needed. Begad! Well, blow me down! It's just a clean and simple design that works.

With t' electronics bay completed, me bucko, arrr, it be time t' turn me attention t' gettin' t' Crossbow ready for paint. Avast! Blimey! I had previously decided t' paint t' rocket usin' NAPA's Martin Senour Crossfire automotive acrylic enamel paint with urethane hardener, me hearties, and settled on a bright Ford color called "Chrome Yellow."

T' rocket was prepped with Martin Senour automotive gray primer, and t' cycle began: prime, me hearties, sand, repeat. Aye aye! I wanted t' get a smooth finish, shiver me timbers, me hearties, but more importantly, I wanted t' get a seamless surface where t' tail cone met t' airframe tube. Blimey! Avast! T' only way t' do that is t' prime and sand usin' a flat sandin' block. It may be a lot o' work, but t' end result is worth it.

I painted t' rocket outdoors, arrr, arrr, behind me shop, on a bright clear October day. Ya scallywag! Even with t' still winds and clear skies, thar were still a couple o' kamikaze bugs who wanted t' spend their lives ridin' rockets. Begad! Ahoy! Blimey! Fortunately, shiver me timbers, all that got embedded seemed t' be feet and legs, matey, and some polish and wax got most o' that out.

Over t' bright yellow finish, I added red and black self-adhesive Monokote trim accents that I cut out myself, along with t' Crossbow decal that came with t' kit. Avast! Blimey! When you install t' decal, use an Exacto knife t' remove t' excess clear tape outside o' t' lettering. Avast! Aye aye! Next was t' Slimline retainer and t' ACME rail guides.

T' author poses with t' Crossbow, me bucko, both sportin' loud yellow wrappings. Arrr! T' Crossbow is loaded with a J260 Skidmark demo motor, made for t' CTI Pro54 2 grain casing.

Ready
Every star wants t' pose for a glamour shot. Ahoy! Blimey!
On Pad
T' Crossbow takes flight on a column o' sparks.
Launch
T' Crossbow's J260SK maiden flight.

I have t' tell you, I did nay follow t' directions on how t' attach t' rail guides and I popped one on t' first launch. Blimey! Blimey! On previous builds, shiver me timbers, I have tried t' use t' sticky tape that comes with t' ACME guides, but it would get hot and fall off! Blimey! This time, I just CAed t' guides right t' t' rocket, matey, ya bilge rat, and it snapped off, clean as a whistle. I am seriously thinkin' about just takin' a countersink and drillin' a small hole right in t' middle o' t' guides and usin' short screws t' attach them. So pay special attention t' t' ACME guides if you use them, shiver me timbers, they require special attention t' get t' stuck and keepin' them there.

T' bright yellow Crossbow got a lot o' attention at Bunnell Blast, shiver me timbers, held on Saturday, November 8th and hosted by t' North East Florida Rocketry Association in Bunnell, me hearties, Florida, just northwest o' Daytona, Florida. NEFAR enjoys acres o' beautiful sod as a launch site, shiver me timbers, and are t' best group t' launch with you can find.

For t' maiden flight, I was offered t' opportunity t' also make a maiden flight o' a CTI J260 Skidmark, arrr, a new two-grain motor configuration cooked up by t' guys north o' t' border. Avast! I can't say enough about t' ease o' use CTI motors offer t' users. Begad! Begad! Assembly was so simple, just stick in t' parts and screw on t' closure. Cleanup be just as easy.

T' weather be as perfect as I have ever seen at a launch, me bucko, with nothin' but clear skies, light winds from t' north, me bucko, shiver me timbers, and lots o' sunlight. Begad! Well, blow me down! I prepped t' motor and put it in t' Crossbow, and then prepped t' recovery and electronics. Aye aye! Aye aye! With me electronics bay design, access was very easy, ya bilge rat, me hearties, which is what I like about 4" rockets - you can get your hands in there.

On t' pad, matey, after t' obligatory creator-creation photo op, t' Crossbow just looked majestic sittin' there. Begad! Begad! It was a very nice design and got lots o' comments from people walkin' t' flight line, me hearties, shiver me timbers, and now was t' moment o' truth. Ahoy! Continuity was checked, t' altimeter armed, ya bilge rat, and then back t' t' LCO desk.

At ignition, shiver me timbers, me bucko, t' big J Skidmark roared t' life and took off for t' north, appearin' t' cone a little. I couldn't decide if it was tryin' t' fly on t' wings or if I got a weird thrust vector. Avast! I would later learn that me aft rail guide snapped off on t' way up and contributed t' t' off-vertical launch. Ahoy! T' Crossbow would streak t' 1974 feet before landin' safely in a pasture across Bunnell Road.

My initial review upon reachin' t' landin' site was t' Crossbow was in excellent condition, with just a few cosmetic cuts and contusions. Arrr! One o' two things occurred at deployment, ya bilge rat, either t' recovery harnesses needed t' be longer or t' ejections charges were too large. Begad! I subscribe t' t' school o' blow 'em up or blow 'em apart, so it could very well have been t' latter. Avast! At any rate, it be a beautiful flight and t' Crossbow performed admirably.

Loaded with style and grace, me bucko, me bucko, t' Crossbow will be sure t' generate a lot o' ooos and ahhhs from onlookers. Avast! Avast! It is an excellent kit for those who like that winged look, those who are desirous o' more than 3FNC, matey, or those who enjoy somethin' out o' t' ordinary. I heartily recommend it and think you will enjoy t' build. Begad! Begad! While I am at it, matey, I also recommend t' dual-deployment version, as it reduces t' typical instability issues o' shorter rockets with large motor mounts, shiver me timbers, as you are goin' t' most certainly want t' put larger and larger motors in it just t' see t' results. T' Giant Leap web site says this rocket is nay for t' faint at heart, but it really wasn't that big o' a deal if you are able t' read things through and follow instructions, or know what t' do should you want t' try somethin' different. If you are up t' t' challenge, matey, give t' Crossbow a shot.

Flights

Comments:

avatar
D.B. (March 31, 2009)
I made the mistake of getting one of these with dual deploy and their "Dyna-Wind" Aeropoxy?d phenolic. I also had the fins beveled, upgraded chute, etc. I was told it wouldn't need nose weight in the DD version and that seemed reasonable. The order was over $400, but the plan was to do the Sledgehammer next if I liked this one. I had to push them a bit to get it shipped out (I forget why I was told there was a delay). The unit arrived well behind schedule but really well packaged with the tubes wrapped in paper. I was initially pleased. However, upon unwrapping the tubes I noticed the payload tube was a work of art. The main airframe was a very similar in appearance to the lunar surface, had major gaps and 'potholes' ranging in size up to approx 3/4" or so. It seems my initial elation was premature--I was bummed. I called Ed and emailed photos (if you'd like copies email me). It seems they were aware of the problem and stated that the guy that does the glassing had been replaced. What that had to do with my tube I do not know. He offered was a return/refund or a $40 credit to keep it. I wanted to build a rocket that weekend and declined a refund. I have ordered CTI cases and Kevlar? tube from them since any they have never offered to credit the $40 off any purchase unless, I imagine, I call and debate it once again. So I start to build. To say the fins were beveled is an under statement, they had literally put a sharp knife edge on a sheet of G10. Pull a wide carving knife from the butcher block and you get the idea. I had the wounds to prove it. Sliced the heck out of my fingers if I inadvertently grabbed it the wrong way and when my cat knocked it over one day it turned out they were so thin the edge would chip easily--they would have never withstood a hard surface landing. So I rounded them off a bit and continued. Anyway, I completed it and painted it in my usual automotive-like fashion. It was a real bear to do the fillets between the wings and the fins. From this experience I learned to steer clear of slotted plastic boat tails, as with the slots weakening it, one must work very hard to get the shoulder reasonably flush with the exterior airframe. It looked nice when I was done but took a ton of work to fill the potholes. It lost something in its "meanness" with the rounded fins also. Keep yours non-beveled. Launch day came so I loaded a CTI J400 38mm motor. Stability was marginal with it pivoting like a see-saw on the wing-lift as it went skyward and finally settling on a 270 degree vector several hundred yards from ground-zero over the palmetto swamp and dual-deploying perfectly. I searched about 3 or 4 hours to no avail. Jinxed from the get-go, good riddance I say. If you find it you can keep the rocket, just return the other stuff please. I still have the lead birdshot for the nosecone for you.
avatar
E.S. (December 4, 2009)
Giant Leap takes customer concerns seriously, but if truth be told, I'm skeptical of D.B.'s negative report. I won't go into detail, but other issues may be involved. Oddly, his report is exactly opposite to what he emailed to us (Giant Leap) after receiving this kit. NOTE: "Absolutely beautiful kit, Ed. You guys are a class act. after a real nightmare with one of your competitors (DELETED) I've found a new home. I did the RockSim file if you need it. Weighed the parts so it should be very, very close. Thanks, (name deleted)" SO.... AS HE NOTES ABOVE, HE PUT IT IN ROCKSIM AND IT CAME OUT PERFECTLY. NO SURPRISE SINCE IT WORKED PERFECTLY FOR OTHER CUSTOMERS AS WELL. SORRY, BUT I'M TAKING D.B.'s REPORT WITH A SERIOUS GRAIN OF SALT. AS THE NOTE ABOVE CONFIRMS, THIS CUSTOMER SEEMS TO BE HAVING A LOT OF "NIGHTMARES" WITH VENDORS.

comment Post a Comment