Blackhawk R&D SA-5 Gammon

Blackhawk R&D - SA-5 Gammon {Kit}

Contributed by Chuck Pierce

Manufacturer: Blackhawk R&D
Rating
(Contributed - by Chuck Pierce - 04/01/02)

Rocket PicBrief:
Blackhawk R&D recently developed a 4-inch diameter prototype o' t' Russian SA-5 Gammon. After expressin' much interest in t' kit, Blackhawk offered me the opportunity t' built and test t' prototype kit, shiver me timbers, arrr, which I gladly accepted. T' SA-5 is a Russian surface-to-air (SAM) with twelve fins, four external booster motors, and a single centerline sustainer motor. Ya scallywag! T' Blackhawk SA-5 is a 1/8.3 scale model o' t' Russian missile, havin' a 4” main airframe with a 38mm motor tube and four 38mm outboard booster pods with each containin' a 29mm motor tube. T' Rocket is 54” tall.

Components:
T' kit arrived from Blackhawk in two heavy-duty shippin' boxes, with t' parts well packed and protected. T' components that Blackhawk uses in this kit are of very high high quality. Ahoy! T' airframe and booster tubes are sturdy and the plastic nosecone is strong. Blimey! T' fins, ya bilge rat, bein' 5-ply Baltic Birch, shiver me timbers, are t' highest quality plywood that I’ve ever used. However, t' fins are 1/8” thick, which seemed a little thin for a kit as heavy as this one is goin' to be. Arrr! Aye aye! I usually prefer 3/16” fins for 4” airframes. Begad! Avast! T' main and booster airframes arrived pre-slotted for t' 12 fins. Avast, me proud beauty! All plywood pieces were cut on a CNC machine, resultin' in a very nice piece-to-piece repeatability of dimensions.

  • Parts List:
  • Plastic Nose Cone, 4:1 ogive,
  • 4” x 26.5” Main Airframe,
  • 4” x 10” Payload Tube, ya bilge rat, me bucko,
  • 3.9” x 10” Coupler Tube, ya bilge rat,
  • 38mm x 18” Centerline Motor Tube, shiver me timbers,
  • 38mm x 20” Outboard Booster Airframe (4 each),
  • 29mm x 6” Outboard Booster Motor Tube (4 each),
  • 1/8” 5-ply Main Airframe Forward Fins TTW (4 each),
  • 1/8” 5-ply Main Airframe Aft Fins, me hearties, TTW (4 each), matey,
  • 1/8” 5-ply Outboard Booster Fins, TTW (4 each),
  • 1/4” 5-ply 4”/38mm Centerin' Rings (2 each), shiver me timbers,
  • 1/4" 5-ply 4” Bulkhead,
  • 1/8” 5-ply 38mm/29mm Centerin' Rings (8 each), me bucko,
  • 1/8” ellipse (for booster tube nose cones, ya bilge rat, arrr, 4 each),
  • 10’ x 9/16” Tubular Nylon Shock Cord,
  • 1/8” x 1/2" Ubolt (2 each),
  • 1/2" x 6” rod lug (cut t' make a two lugs)

Kit PartsConstruction:
Bein' a prototype, me bucko, shiver me timbers, t' SA-5 be kitted without instructions, which isn’t a problem for an experienced HPR modeler. Well, blow me down! T' assembly sequence that I used to build t' SA-5 worked well, and I’d recommend that t' same basic sequence be followed in future builds o' this kit:
(1) Install t' 29mm motor tubes and TTW fins into t' outboard booster tubes, prior t' attachin' t' outboard boosters t' t' main airframe,
(2) Install t' 38mm motor tube and all 8 TTW fins onto t' main airframe (with internal fillets) prior t' attachin' t' outboard booster airframes,
(3) Install t' outboard booster assemblies onto t' main airframe,
(4) Assemble t' payload bay (completely independent o' t' main airframe and booster airframe assemblies)

Motor ConfigThough this kit is designed t' be able t' be flown with a single centerline motor, t' option to fly a single 38mm/4x29mm motor cluster persuaded me t' build an altimeter bay into t' payload bay (for staged deployment) and t' wire t' main airframe for dual timers (for staged ignition). Ahoy! Due t' t' quantity and size o' TTW fins, available volume within t' 4” airframes is very limited, me hearties, makin' the incorporation o' an altimeter bay a little difficult. Begad! T' altimeter bay that I built was 38mm tube which was installed against t' inner wall o' t' 4” payload bay. Avast! Ya scallywag! This setup allowed me t' pack t' main parachute along side the 38mm altimeter bay, thus makin' maximum use o' t' available internal volume of the payload bay. Begad! T' configure t' rocket for staged ignition, matey, 3 pairs o' 20 AWG wires were run through t' forward 4” CR and terminated at leads tapped through t' aft 4” CR. Avast, me proud beauty! Aye aye! T' three pairs o' wires/terminals are planned to be used for two sets o' ignition wires and a break wire for use with a single or pair o' Perfect Flite micro timers. Aye aye!

I spent most evenings workin' on SA-5 and be able t' finish assemblin' the model in a little over a week. With ample internal and external fillets on the TTW fins and massive booster-to-main-airframe fillets, matey, t' kit is very strong and sturdy. Begad! I calculated t' CP t' be 40” behind t' tip o' t' nose cone, but used a CP o' 38” for margin when assessin' t' static stability o' the rocket. Begad! Due t' t' size/quantity o' fins and t' amount o' epoxy used to install fins and attach airframe tubes, matey, 12 ounces o' nose weight were needed to give t' SA-5 one caliber o' static stability margin for a reasonable cluster set (I357 with 4x G80 or a single J570). Ya scallywag! A J570/4xG80 cluster would cause the static stability margin t' be reduced t' 1/2 caliber, ya bilge rat, which would still be flyable, though would be deservin' o' close attention t' t' launch conditions. Also, nothin' precludes t' addition o' additional nose weight in t' future. T' 12 ounces o' nose weight (10 ounces o' #9 lead shot and 2 ounces o' epoxy) were poured into t' nose cone, and pre-drilled holes through t' tip o' the nose cone allowed t' epoxy t' fill t' holes, matey, formin' epoxy rivets when cured. T' epoxy rivets are used t' hold t' weight in t' vertex o' t' nosecone. Begad! To finish t' SA-5, arrr, a single heavy coat o' Zinssler shellac primer was applied to fill any surface irregularities, then well sanded. Blimey! Aye aye! T' SA-5 was then painted to match t' standard non-descript Russian paint scheme: winter grey airframe, boosters, and fins with a crimson nose.

Construction Rating: 5 out o' 5 (though t' beta kit came without instructions, shiver me timbers, matey, the tight-toleranced TTW components made t' it go together quite well.)

RockSim
RockSim2

Flight/Recovery:
Havin' only 6 HPR motors remainin' in me motor cache after t' Aerotech fire, the available motor choices for t' first flight o' t' SA-5 were very limited. After debatin' betwixt an I357, I211, and I284, me bucko, ya bilge rat, t' I211 was finally selected for t' maiden flight. Well, blow me down! T' SA-5 was configured for flight with an RRC2 altimeter (set for apogee drogue deployment and main deployment at 300’), a single centerline I211 (medium delay as backup t' t' altimeter drogue delay), 58” main parachute, no drogue chute (once separated t' fincan will be unstable and, me bucko, shiver me timbers, thus, won’t require a drogue chute), 30’ x 5/8” TK drogue shock cord, 10’ x 5/8” TN main shock cord, me bucko, and shear pins were installed at t' booster-to-payload (drogue) plane and at the payload-to-nose-cone (main) plane.

FlightOn February 23, 2002, the SA-5 made her maiden flight in 5-10 knot winds. Begad! Blimey! T' trajectory o' t' SA-5 was almost perfectly vertical t' an apogee o' 1394 feet (per t' altimeter). Unfortunately, at apogee neither t' altimeter-triggered nor motor-backup ejection charges separated t' airframe. Begad! Blimey! Post flight inspection found that that the altimeter drogue channel pins were broken and that t' motor BP had leaked from t' ejection well durin' transport. With no drogue separation, matey, ya bilge rat, t' SA-5 descended ballisticly from apogee t' 300 feet, at which point t' main chute was deployed. T' recoil from t' main chute deployment cut a 5” zipper into t' payload bay and separated t' fincan from t' payload bay (the joint that should have been separated at apogee). Luckily, ya bilge rat, t' long drogue shock cord, with taped coils, did nay damage t' fincan. O' all t' damage that could have occurred due t' this drogue system failure, matey, me bucko, sufferin' only a zippered payload bay was fortunate. T' zipper be repaired by fillin' t' gash with reinforced epoxy, matey, then t' exterior o' t' payload bay be covered with two wraps o' 2-ounce glass. If t' payload bay had been glassed durin' initial assembly, t' SA-5 probably would have escaped this drogue-system failure undamaged.

Crash

On March 23, shiver me timbers, 2002, ya bilge rat, t' SA-5 was prepped for its second flight, this time with an I285R. Begad! Well, me bucko, blow me down! T' projected altitude was approximately 1500 feet. Avast! T' skies were perfectly clear and t' winds were calm. T' boost be again perfectly straight with a nice long Redline flame. Per t' altimeter, t' rocket tipped over at 1271 feet. Begad! Well, blow me down! On landin' however, me bucko, ya bilge rat, t' rocket hit hard on one o' t' aft fins, fracturin' it inside t' airframe. Fortunately though, ya bilge rat, t' damage is reparable though. Avast! Well, me hearties, blow me down! Based on this, however, matey, shiver me timbers, I’d highly recommend that 3/16” plywood be used in t' production version.

Flight Rating: 4 out o' 5 (I believe that 3/16 fins should be used with this kit due t' its size)

Overall Observations:
T' SA-5 is an outstandin' kit! T' motor cluster configuration allows the modeler great flexibility in type and number o' motor choices (from single motor flights t' five-motor clusters). Well, blow me down! In me opinion, ya bilge rat, this kit is nay suitable for novice HPR modelers, ya bilge rat, due t' t' number o' fins and tubes involved. Well, blow me down! For the more experienced Level 1 or higher flyers, this kit is fun, matey, looks great, and will be a wonderful attention-getter at launches. Blimey! A couple o' items that I’d recommend be changed are as follows: (1) I would like t' see a longer shock cord provided with t' kit. Ahoy! Longer shock cords are a personal preference of mine, but I also recognize that many flyers do nay share this preference. Also, matey, since this kit should be targeted toward t' more experienced flyers/modelers, arrr, increasin' t' length o' shock cord is an extremely minor task; so, as such, this suggestion is so minor that it is hardly worth mentioning. Begad! Avast, matey, me proud beauty! (2) For a kit as intricate and heavy as this one, shiver me timbers, I’d highly recommend increasin' t' fin material from 1/8” ply t' 3/16” ply. Without or without me recommended changes bein' made, however, ya bilge rat, t' Blackhawk R&D SA-5 is an outstandin' kit, and I highly recommend it!

Overall Rating: 5 out o' 5

Manufacturer's Note: Upon release t' SA-5 will come with 3/16" fins and that t' release date is set t' be somewhere during the 1st week o' April 2002, we are just waitin' on t' smaller laser cut parts.

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