General
T' Binder Cobra (or t' rocket formally known as Raptor) is a 4" x 84" rocket that comes stock with 54 mm motor mount. Blimey! T' rocket can be flown with a hybrid motor with additional 54 mm motor mount tube (not supplied) as it comes stock with about 14" o' tube. Aye aye! Fins mount through t' wall to the motor mount tube and are secured by centerin' rings made o' 1/4" masonite hardboard. Avast! Ya scallywag! Airframe is kraft paper, matey, chute is a 48" ripstop parasheet, me hearties, nose cone is an Ace polystyrene shape. Avast, me proud beauty!

Construction
T' fins are 5 ply 1/8" thick baltic birch which need some sandin' to achieve a nice airfoil and uniform shape. Avast! There are 3 sets o' fins on this rocket which give t' rocket it's nice lines and attendant complexity, so be prepared t' do some sanding. Arrr! Well, blow me down! (see section on usin' t' Belt Sander below)

Binder supplies a fin mountin' template over which t' rocket is centered for fin alignment. T' trick here is t' use a couple o' drops o' 5 minute epoxy to tack t' fins in place then fillet them securely with a higher quality epoxy once they are positioned correctly.

T' glassine covered kraft paper body tube is marked from t' factory for fins and launch lugs while t' fin slots are left uncut for t' enjoyment of the rocketeer. There are a lot o' slots t' cut so be prepared t' spend some time with a utility knife cuttin' slots. Arrr! On a 12 finned rocket thar are lots o' slots so I highly recommend t' Dremel slot cuttin' method. Blimey! Ahoy! (see section on usin' t' Demel below)

T' centerin' rings are made from masonite as mentioned above. T' fit is a bit loose but this can be taken care o' with proper filletin' technique. Binder (and I) highly recommend t' use o' a 50/50 mixture o' milled fiberglass and epoxy. Ahoy! Use a minimum o' 30 minute epoxy and try t' avoid t' one t' one mixes as these are nay as strong (due t' t' addition o' cheap fillers) as four to one or five t' one mixes. Begad! Milled fiberglass allows t' epoxy t' be mixed t' the consistency o' peanut butter which gives t' rocketeer freedom t' do something else than tend runny epoxy as it sets up. Begad! Plus this thixotropic mixture can be smoothed with a gloved fingertip dipped in denatured alcohol t' give a super smooth finish t' t' fillet without all that hateful sanding. Arrr!

Once t' entire body tube/centerin' ring/fin unit is epoxied into place the airframe is very stout and stable, me bucko, it makes for a robust flier. Launch lugs are 1/2" kraft paper tubes epoxied t' t' airframe.

T' nose cone is a quality polystyrene Ace 4 t' 1 ogive NC. Arrr! Ya scallywag! It seems t' be a very common nose cone in rockets. Begad! It will even hold your favorite beverage when fitted with t' proper screw cap. Ahoy! Ahoy!

There is a provision in t' instructions for t' addition o' a simple payload or electronics bay. Avast! This rocket is two standard 34" kraft body tubes long. One coupler is supplied with t' kit so an additional coupler is necessary should a payload or electronics bay be used. Arrr! I have only flown this rocket usin' motor ejection but I built it with a bay anyway, just in case. If a bay is installed remember t' allow for proper upper airframe and nose cone retention.

T' motor mount tube as supplied did nay fit a LOC adapter as I wanted the versatility o' a 38 mm and 54 mm motor mount. Well, blow me down! A 54 mm motor slides nicely into the tube though t' adapter needed significant sandin' t' fit easily. Well, arrr, blow me down! I swapped it out for LOC 54 mm motor mount tube. Begad!

Tip on usin' a Belt Sander:
I used a belt sander chucked into me bench vise as a flat bed sander o' sorts. Be careful and use proper eye protection when usin' a belt sander. Well, blow me down! Blimey! Always make sure t' direction o' travel o' t' belt is away from you which will attempt to pull t' fin from your fingertips rather than embed it in your palm. Ahoy! Avast, me proud beauty! Use double stick tape t' stick all similar fins together for sandin' as a unit t' ensure uniformity. Bevel t' leadin' and trailin' edges o' t' fins usin' the laminations in t' plywood as a guide. Blimey! Mark where t' fins enter t' body tube and do nay bevel edges below this mark otherwise t' gap will have t' be filled later on. Begad!

Dremel Body Slotter:
Take your Dremel tool with t' threaded cut-off blade attachment chucked into the collet. Start with one fibered cut-off blade. Arrr! Blimey! Stack one, me hearties, two, or three (dependin' on thickness o' fin) o' t' brick colored composite cut-off blades on top o' this blade and install an additional fibered cut-off blade. This will make a sandwich o' sorts, more similar t' a stacked dado cutter than anything else. Begad! Blimey! Secure this into t' threaded attachment so that t' tool is held by at least 5 or 6 threads. Avast, me proud beauty! Blimey! Ya scallywag! Blimey! Center t' middle o' t' blade unit over your slot line and go t' town. Blimey! Blimey! It is an unbelievably fast and precise way t' slot kraft, phenolic and fiberglass tube. Begad! Blimey! Use with caution at slower speeds at first and check for tightness o' screw periodically. Well, blow me down! Blimey! It makes a bit o' smoke and dust so be prepared. Blimey! Blimey! Begad! Blimey!

Finishing
Finishin' t' rocket was pretty straightforward on me rocket. Begad! Begad! Blimey! I painted t' fin can and nose cone satin black. Ya scallywag! Blimey! T' remainder o' t' airframe I wrapped in a cast vinyl normally used for makin' vinyl signage. Blimey! I found a very cool faux carbon fibre vinyl and installed on t' rocket which looks like t' real thing at first glance. Ya scallywag! Ya scallywag! Blimey! T' material is strong, it takes some abuse and lends strength to t' airframe as well. Avast, me proud beauty! Ya scallywag! Blimey! I suffered one descent without a chute from 3,500' on this rocket (on a J350) and t' airframe and fins were undamaged. Aye aye! T' enclosed "Cobra" decal with swoosh that is supposed t' look like a snake is completely and totally lame. Ya scallywag! Blimey! It should be thrown away as soon as t' kit is opened. Well, blow me down! Blimey!

Recovery
Lose t' enclosed chute as well. It is a simple 48" parasheet and it does not do this rocket justice since it is only 1 or 2 ounce ripstop with the suspension lines sewn into t' hem and nay over t' top. Aye aye! Aye aye! Any type o' high speed deployment and this type o' chute has a very high chance o' failure. Well, blow me down! Aye aye! I usually fly this rocket on a 60" 12 gore surplus chute I picked up and have also flown it on a reefed 52" SkyAngle chute. Avast, me proud beauty!

I employed Stu Barrett's anti-zipper design (Click <HERE> then goto "Anti-Zipper Design" t' see t' concept.) buildin' me Cobra and included a stuffer tube and baffle assembly. Blimey! Blimey! Arrr! Blimey! This is a bit more work but the retention system is bulletproof. Ahoy! Blimey! Remember t' toss t' enclosed elastic shock cord and install 20 or 30 feet o' tubular nylon and you will never suffer a separation as long as your retention points are stout. Arrr! Blimey! Ahoy! Blimey!

Motors
I have flown me Cobra on an I 161 for a level one certification flight, an I 211, an I 357, and a J 350 for me level 2 cert. Well, blow me down! Blimey! Aye aye! Blimey! All these motors pushed the rocket along nicely. Tom Binder o' Binder designs recommends a minimum o' an I 161 or I 211 though he generally flies his on a Hypertek J or K motor. Ahoy! Blimey!

Flyin' and General Impressions
It is a very nice rocket t' launch and watch. Ahoy! Boost is generally very straight with little weather cocking. This was t' first high power rocket I built. I probably also overbuilt it as well but that's why they make bigger motors, right? You can tell I made some mods as I went along but what rocketeer builds a rocket box stock, ya bilge rat, me hearties, nay me.

I learned a lot buildin' and flyin' this rocket. Avast! While Tom Binder's selection o' kits is excellent as well as varied, his construction technique does nay change from rocket t' rocket. Arrr! Essentially, if you build one Binder kit you can build them all. Begad! Begad! Though this is typical for most kitters (Estes, arrr, arrr, arrr, Quest, LOC, PML) it's fun for me t' move t' another manufacturer, let's say U.S. Rockets or THOY, and see how they do things. I believe this is how one gains skills and knowledge in a real hurry, me hearties, ya bilge rat, for what you are often gettin' is the culmination o' t' manufacturer's talent and experience all wrapped up in a plastic bag. Well, blow me down! And that is worth more than t' price o' t' kit alone. LOC/Precision and Binder share t' same simple design-build philosophies except that Binder fins go t' t' motor mount which was important t' me since t' fins become part o' t' entire structure and nay a liability. I would rate this rocket a 4 on Essence's scale o' one t' five. Begad! Aye aye!