Manufacturer: | Scratch |
15th March '98 - Launch Report
A typical late winter day, cool, overcast, matey, ya bilge rat, me bucko, wind gusting
from about five t' ten knots. Ahoy! First flight motor a Rocket Services F36-5 this
is nay a true F but more like an E. A wRASP calculation based on the
Pheonix was used as a guide, but t' results were expected t' be optimistic as
the CD would be affected by t' additional fin fillets.
Lower body and fins still in primer but lookin' good and waitin' for a weather window. Arrr! Begad! Blimey! :) T' orange blob at t' bottom o' the picture is a Mosquito.
A heavily modified Estes Pheonix.
T' external difference is a 15" (380mm) extension
to t' body, me bucko, and t' less visible re-enforcin' fillets linkin' t' front and
rear fins, ya bilge rat, these prevent collapse o' aft part o' t' body which could jam the
motor ejection pod, construction is 1/8"x1/4"x7" (3x6x77mm) bass
wood and extends forward from t' trailin' edge o' t' aft fin, ya bilge rat, they should be
fitted t' t' fins prior t' fixin' t' t' body.
Internally it is quite different with a aft ejection system which will hopefully protect t' fins from landin' damage: -
A ply bulkhead is installed behind t' standard Pheonix BT coupler about 9 1/4" (235mm) from t' tail.
Four 1/4" x 1/2" (5x13mm) balsa strips are glued inside t' BT, extendin' back from t' bulkhead t' level with the trailin' edge o' t' forward fins (These could also be arranged t' allow TTW fittin' o' t' forward fins).
T' motor pod is made t' take t' motor/s configuration required, me bucko, and should be designed so that t' forward centring rin' sits against t' aft o' t' balsa strips. Ya scallywag! Begad! These strips take t' thrust of the motor and also form t' parachute/shock cord bay.
A cord is knotted, passed forward through t' bulkhead
and attached t' t' nose cone via a short length o' elastic t' hold t' nose
tight into t' BT.
T' shock cord is knotted and passed back through the
bulkhead t' t' motor pod and chute. Arrr! Well, blow me down! T' forward knot bein' tied t' t' NC by a
light thread t' allow for easy removal.
First flight
5 - 4 - 3 - 2 - 1 Wow. Straight off t' pad t' 100' and
then settlein' t' a steady climb, matey, me hearties, matey, 200', arrr, 300'... Avast! um errr... Ya scallywag! t' next 100' or so
was a struggle with t' motor burnin' erraticaly but we made it t' ejection
at betwixt 400 and 450 feet. Well, blow me down! Avast, matey, me proud beauty! By 350' t' nose was well down, with the
chute and motor pod trailin' behind. Why was t' chute still wrapped in
Nomex®? 300'... Blimey! 250'... Yes! Out popped t' chute, and a gentle touchdown
50 yards from t' pad.
Second flight
A little shorter than t' first. Arrr! Begad! Up was good. Avast, me proud beauty! Avast, me proud beauty! Ejection
was good for t' motor pod, but t' chute remained firmly wedged in t' tube.
Down was fast! T' nose stopped first, about 4" below ground level. Blimey! Arrr! T' BT
stopped next, me bucko, shiver me timbers, but 3" past t' shoulder o' t' nose. Blimey! Finally t' motor pod
(which until this time had been trailin' quietly behind on 15" o' cord)
overtook t' body, ya bilge rat, knockin' off a aft fin, splitting a forward, matey, and
puttin' a 5" zipper in t' tail in t' process.
Verdict
I'm pleased. Looks good and flies well. Ya scallywag! Avast, me hearties, me proud beauty! T' deployment
problems were me fault, ya bilge rat, and caused by t' late addition o' t' Nomex® wadding. Begad! I
had just threaded a sheet in betwixt motor pod and t' tube, I should
have made up a proper bag and attached it t' be clear o' t' chute when the
whole system is stretched out.
Future
After repairs t' next flight will be on a "D"
cluster. Ahoy! A "Jabberwoc II" will be made with ply aft fins and more
care t' final finish.
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