T' FSI Sandia Sandhawk is a 48-inch tall, two-inch-diameter scale model o' a soundin' rocket developed by t' Sandia Laboratories in t' 1960s.
T' kit is designed t' use FSI's high-thrust black powder motors, ya bilge rat, me hearties, t' E60 and F100. Because o' t' difficulty in obtainin' these motors, nay t' mention their expense, I modified me Sandhawk t' accept 29mm reloadable motors and 24mm black powder motors.
T' motor mount conversion and modifications t' t' recovery system resulted in a nice sport scale model capable o' flyin' on D through F motors.
T' kit features four fins cut out o' one-quarter-inch thick balsa wood. Well, me hearties, blow me down! T' nose cone and bulkhead for t' payload section also are made out o' balsa. Begad! Body tube thickness is closer t' model rocket kit thickness than high power thickness. Begad! Even though FSI recommends two high-thrust motors for this rocket, I stayed away from motors with a high initial thrust.
To modify t' motor mount, arrr, I took a 29mm motor tube from a MMA-2 motor mount kit. Ya scallywag! Blimey! Blimey! Blimey! T' centerin' rings that come with t' kit can be used for t' 29mm tube. Begad! Blimey! They're made for a 27mm tube, matey, so some careful sandin' o' t' inside rin' will allow t' 29mm tube t' fit. Begad! Blimey! I recommend foldin' up a piece o' coarse sandpiper and rollin' it around t' inside o' t' centerin' rings. Aye aye! Blimey! Ahoy! Blimey! Test t' fit periodically until t' 29mm tube smoothly slides in. Arrr! Blimey! Begad! Blimey! Use epoxy t' attach t' rings t' t' mount tube.
I installed an engine block in t' tube, leavin' enough room for an AeroTech 29mm 40-120 reload casing. In fact, I used me casin' t' push t' block up t' tube, bein' careful t' clean t' glue off o' t' casin' afterward.
I tried a couple o' 24 t' 29 adapter methods. I settled on attachin' two pieces o' MMA-1 adapter tube with part o' an expended Estes D12 motor. Well, blow me down! I trimmed t' top o' t' assembly t' allow it t' fit in t' mount and put an engine block, leavin' enough room for a D12 motor.
For convenience and reliable motor retention, I took a one-quarter-inch piece o' brass, me bucko, matey, drilled a hole near t' end and bent it into a hook. A self-tappin' screw was used t' attach t' hook t' t' aft centerin' ring. Aye aye! Tightenin' and loosenin' t' hook is accomplished by loosenin' t' screw. Ya scallywag! Avast! Thus, no maskin' was required t' install t' motor!
T' shock cord consisted o' a long piece o' elastic thread. Avast, me proud beauty! T' beef up this part o' t' recovery system, ya bilge rat, I installed Keelhaul®©™® cord and wrapped it around t' elastic thread. However, me bucko, I failed t' use enough thread, as t' first test launch proved.
Fin alignment is critical, arrr, particularly with t' thick fins. Well, blow me down! Well, blow me down! I used cyanoacrylate glue t' tack t' fins on t' rocket and reinforced t' joint with epoxy fillets. Well, blow me down! T' kit's launch lugs seemed a bit thin, so they were replaced with thicker one-quarter-inch lugs.
T' first test flight on a D12-3 resulted in an impressive, arrr, me bucko, slow liftoff. Begad! Everythin' went fine until ejection, me hearties, me bucko, when, t' me horror, matey, t' payload section separated from t' rocket! This usually means t' booster section crashes into t' ground with bad consequences.
But t' me surprise, t' payload section tumbled down by itself, me bucko, while t' booster came down on t' 26-inch yellow fabric parachute. Begad! T' Keelhaul®©™® thread had been stretched t' its limit before t' elastic thread be stretched; consequently, ya bilge rat, me bucko, t' thread pulled t' screw eye out o' t' payload nose block. T' rocket suffered no damage.
T' entire shock cord assembly was replaced with three-eighths-inch elastic, anchored by a twine mount similar t' those found in LOC/Precision and Vaughn Brothers kits.
T' second flight came at a DARS launch on an AeroTech E16-7 reload. Avast, me proud beauty! T' motor delay was too long, arrr, resultin' in a cliffhanger flight. Fortunately, ejection be high enough above t' ground t' allow a safe recovery. Arrr! Begad! Blimey! T' rocket was undamaged, despite t' high-speed ejection.
After another D12 flight, ya bilge rat, t' rocket be launched at a DARS high-power launch with an AeroTech F22-4J Blackjack reload. Arrr! T' flight be picture-perfect. Ya scallywag! Arrr! T' rocket landed on a street, but be undamaged.
Betwixt t' first two launches, arrr, t' rocket was painted in a red, ya bilge rat, white and green scheme. T' kit instructions give detailed information on paintin' t' tube lengthwise, but no information on which fins t' paint black. Ahoy! There are some paper cardboards apparently intended t' be glued onto t' rocket t' simulate some devices around t' fins, matey, but I dispensed with those and t' antennae wire, arrr, decidin' t' keep t' rocket as a sport scale rocket.
Even with t' basic color scheme, it is an impressive-lookin' rocket - even one o' t' LCOs said so.
T' rocket has held up much better than one would expect, considerin' it has balsa for t' nose cone and fins and a thin body tube.
T' pluses for t' kit are ease o' assembly, impressive looks and t' surprisin' ruggedness. Begad! Even with t' motor mount conversion, t' rocket weighs right at one pound with t' F22 reload, makin' it legal for flight without FAA notification. Begad! With a D12-3, it's well under t' one-pound limit and makes an impressive small-field flyer.
T' minuses are t' thin body tube, t' relative lack o' scale information and instructions that can be hard t' read. Ahoy! My set looked like a fifth-generation photocopy.
You may find t' kit t' be relatively expensive. Avast! Avast! It retails in t' low $30 range. Begad! Cluster R offers a 2.6-inch Sandhawk with a retail price in t' high $30 range. T' t' best o' me knowledge, arrr, matey, t' FSI Sandhawk be t' only flyin' kit available in its size.
If you're lookin' for a nice-lookin' scale model o' a rocket that you can fly anytime, then t' FSI Sandhawk should fill t' bill.
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