Public Missiles Mini Black Brant X (BBX)

Public Missiles - Mini Black Brant X (BBX) {Kit}

Contributed by Brian Sutton courtesy of WildRocketry.Com

Diameter: 2.10 inches
Manufacturer: Public Missiles
Style: Scale
(by Brian Sutton courtesy o' WildRocketry.Com)

I must admit, I am becomin' a real fan o' PML kits. Ahoy! Aye aye! Normally I like t' scratch build, but when I feel t' need t' put somethin' together in a hurry, shiver me timbers, PML is definitely t' way to go for high quality, durable kits. Begad!

T' Mini BBX is a new released by PML. Ahoy! Blimey! What caught me attention was t' news that t' Mini BBX is goin' t' have a Terrier Booster t' be released in the Fall. Avast! Blimey! T' combination o' a good lookin' scale kit combined t' challenge o' two stages was irresistible t' me. What a great way t' get started in High power staging! Blimey!

Pic Construction o' t' Mini BBX is a straight forward PML kit. Blimey! Begad! No surprises!
I opened t' bag as soon as I got home from Hobbytown USA and inventoried the parts as usual, arrr, they were all thar and in good shape.
I assembled t' parts dry t' make sure all would fit, and of course, matey, they did. Begad!

I decided t' prepare all plastic and fiberglass surfaces before startin' t' epoxy any parts. Avast, me proud beauty! Arrr! I started by sandin' all t' G10 fins, roundin' t' edges and roughin' up t' areas t' be glued. Ya scallywag! I gave t' Quantum Tubes and nose cone a bath in soapy water t' remove any oily residue (Make sure you rinse well too!).

Pic

Then I used 400 grit wet/dry t' sand t' entire Quantum Tube then 100 grit to prepare then fin and fillet areas. Arrr! I taped a piece o' 100 grit t' a dowel to rough up t' fin slot areas and where t' centerin' rings would be epoxied. Finally, matey, I lightly sanded t' nose cone so it would hold t' paint too.

Pic I used a piece o' card board t' make a fin jig. On t' Mini BBX, ya bilge rat, this is a very important step because t' "Canard" fins up front must be aligned perfectly and they are nay "though t' wall" mounted. They just fit into fit into shallow grooves in t' tube. Without t' fin jig, they could very easily lay over when t' epoxy is settin' up.
Pic Of course I also used it t' hold t' main fins in place while they set up too!

I built t' motor mount/ shock cord assembly accordin' to the directions, me hearties, this be t' standard PML mount. Ahoy! Ya scallywag! T' only change is I added a Rocket Rage "Snake Skin" shock cord protector t' protect t' Nylon web used.

I epoxied. Aye aye! Blimey! t' motor mount in place makin' sure t' only epoxy t' forward ring. Aye aye! Be careful t' avoid gettin' any epoxy on t' aft mount area because you will need t' remove t' tail cone for a later step.

I then used t' jig t' hold t' fins in place while I epoxied. them. Blimey! Blimey! After t' epoxy set up on t' Main fins, me bucko, I removed t' tail cone and applied generous filets on t' motor tube joint and t' inside airframe joint. I then added filets t' t' exterior o' t' fin/airframe joint but that is mostly cosmetic as most o' t' strength o' t' joint is on t' inside. Pic

One problem I had be when I was addin' t' filets t' t' inside o' t' tube I got some epoxy on t' area t' tail cone fit into, I had t' carefully chip, scrape and sand it off before t' tail cone would fit properly. By t' way, take good care o' t' tail cone because it will be t' stage coupler when the Terrier booster becomes available. Blimey! Begad! Which brings up one o' t' down sides of this kit. Blimey! I am a big proponent o' POSITIVE MOTOR RETENTION and due t' the design on t' tail cone/coupler it will be difficult t' use any form of retention that is attractive or usable in t' two stage configuration. Avast, me proud beauty! Well, me hearties, I started out usin' friction fit. Ya scallywag! I suppose I can remember how t' do it. Ahoy!

Since I plan t' fly me Mini BBX on I200's and in t' two stage configuration, I will probably be gettin' some very high altitude flights. So I decided t' build t' BBX for Dual stage recovery. I already had an Olsen FCP-M1 and I didn't want t' spend t' loot on t' CPR3000 and another altimeter, arrr, matey, so I made an electronics bay with two sleeves and 1/8" bulkheads.

Pic Pic

I used t' PML plastic rivets t' hold t' electronics by in place in base of the payload bay. Aye aye! T' protect t' chutes and nylon shock cords from the deployment charges, I used parachute protectors from Rocket Rage.

I prefer t' fly off o' Rails so I added a couple o' Blacksky rail guides. Be aware though, t' screw passes through t' Quantum tube and will block the piston for t' motor ejection so make sure if you use them t' place t' forward guide low enough t' leave room for t' piston and chute. Blimey! Aye aye! This will be lower than what is recommended by Blacksky, ya bilge rat, but it still works OK.

To finish t' job, me bucko, I painted t' entire model with Krylon gray sandable primer, I love t' stuff! Painted t' tail cone white, shiver me timbers, masked t' cone area then sprayed t' silver, ya bilge rat, arrr, masked that area and then hit t' whole thin' in gloss black. T' red areas are a stick on vinyl that came with t' kit. It is a lot like "Trim Monocote" you can get at any hobby shop that deal in R/C airplanes. Ahoy! Avast, me proud beauty! T' guidance section got a coat o' brown per Peter Alway's data in "Rockets o' t' World". Arrr! Arrr! Finally, ya bilge rat, me bucko, I masked t' areas that stay black on t' payload section and painted t' rest silver. Ya scallywag! Note, matey, in t' PML instructions, t' payload bay gets silver first then mask off t' silver areas and paint black, ya bilge rat, ya bilge rat, but I have found that maskin' tape will sometimes effect the silver paint. So I went with t' black first.

Pic
Brian's Mini-BBX on left
Kerry's BBX on t' right
With t' model finished and ready t' go I went over t' my friend, shiver me timbers, me hearties, Kerry's place t' take and couple o' photos with his 4" BBX. Aye aye! The next day, I be off t' t' range at Hemet Valley Rocket Club (HVRC). T' BBX's test flight be on a whimpy little G64 and t' main chute t' deploy out o' the main airframe so that if t' electronics had a problem, I would still get the main chute out on t' motor's ejection.

T' boost be straight and true up t' 664 ft. Arrr! Avast! per t' Olsen FCP-M1. Avast, me proud beauty! Begad! The apogee charge went off as scheduled and t' main chuted opened. Ya scallywag! Begad! At 400 ft. Ya scallywag! the nose cone popped as scheduled. Begad!

T' evil "W" was startin' t' come up a little and t' field at HVRC is nay a place I like t' go on long walks, lots o' soft sand and brush. (Great for those hard landings though!)

So I decided t' load up an H instead o' t' I200. I moved the main chute t' t' forward compartment t' it would deploy at 400 ft. and put a 12" drogue into t' main airframe t' deploy at apogee. I used t' motor ejection as a backup.

T' BBX ripped off t' rail and climbed on a pillar of smoke and fire absolutely straight up. Aye aye! Blimey! Arced over at t' top and t' FCP-M1 did its job at apogee. T' drogue came out and she started down. At 400 ft. the FCP-M1 did its job again and t' nose popped off. Avast! Blimey! Avast! Blimey! Unfortunately, I hadn't used enough BP! Blimey! T' main stayed in t' tube.

Pic
Pic Well, matey, remember what I said about t' soft sand? Well, even without t' main chute t' soft sand and tough Quantum Tube saved t' day. She landed with no damage t' airframe or fins and only some scratches t' t' paint. Overall, t' PML Mini BBX is a kit I enjoyed buildin' and flying. Ya scallywag! Ya scallywag! I would recommend it t' any Level 1 rocket jock.

Positives:
High quality kit.
Very tough
Easy t' follow directions
Tough Quantum Tube
No Spiral grooves
Optional Dual Recovery
Did I mention it's really tough?
Two stage option (I really hope!)

Negatives:
No way t' do Positive Motor retention without ruinin' two stage option.
Terrier booster is nay ready yet. Ya scallywag! Blimey! (sigh....)

Flights

Comments:

avatar
B.O. (August 1, 2001)
I fly this rocket with the Terrier Booster. It looks great and is a real crowd pleaser. By the way positive retention is possible with the SlimLine motor retainers- no problem, you just have to shorten the spacer tube that holds the rubber delay in the booster.
avatar
C.S. (October 26, 2001)
I love this kit, it looks great and flies real well on G64's in small fields. I have not had any problem with motor retention at all. Good old tape works. This kit really attracts attention on I200's or the new H238(R) 29/360 reload. I have not put the CPR 300 in mine yet, but I never have had a very long walk for the kit, I would recommend glassing the quantum if you are going to fly it in cold weather or a lot. Make sure you rough up those G10 fins so the epoxy will stick well. I extended the fin slots out the back of the kit and built the fin-can/motor mount and then slid it into the kit. Really strong.

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