blackshire
09-02-2010, 05:57 PM
Hello Doctor (and all other readers here on YORF),
The folks at the Northcote Heavy Horse Centre www.northcotehorses.com will be incorporating model rocketry activities into their special event days, and I am sending them an initial batch of 24 Estes Viking kits along with 1/2A6-2 or A8-5 motors (ordered from Sierra Fox Hobbies in Italy) and other launching supplies. Due to the relatively small size of their available flying field (their jousting field), they will use only "1/2A" or "A" motors in the rockets. I have a question about the Estes Viking's CG (Center of Gravity):
The "worst-case scenario" (in terms of forward CP [Center of Pressure]) Viking fin configuration is just three fins, glued on with their longest edges as the root edges and with their wider ends forward, as in Moe Bertrand's photograph (attached below) from the EMRR article on the Estes Black Diamond (see: www.rocketreviews.com/images/flightlog/bd1e.jpg and www.rocketreviews.com/reviews/all/est_black_diamond.shtml ), a re-packaged Estes Viking in a different "livery" that came in the "Launchables" (#1452) Starter Set. (This Viking configuration resembles the Estes Cherokee-D.) My question is: With this "worst-case scenario" fin configuration, is the Viking aerodynamically stable with 1/2A6-2 and/or A8-5 motors, or would it need clay ballast in the nose cone? (I know that the Estes Viking [although not the old Centuri Viking and Akela-1] *definitely* needs clay nose ballast if flown using heavier "C" motors with this fin configuration.) If necessary, I will provide them with clay for ballast.
Many thanks in advance to you and/or anyone who can help!
The folks at the Northcote Heavy Horse Centre www.northcotehorses.com will be incorporating model rocketry activities into their special event days, and I am sending them an initial batch of 24 Estes Viking kits along with 1/2A6-2 or A8-5 motors (ordered from Sierra Fox Hobbies in Italy) and other launching supplies. Due to the relatively small size of their available flying field (their jousting field), they will use only "1/2A" or "A" motors in the rockets. I have a question about the Estes Viking's CG (Center of Gravity):
The "worst-case scenario" (in terms of forward CP [Center of Pressure]) Viking fin configuration is just three fins, glued on with their longest edges as the root edges and with their wider ends forward, as in Moe Bertrand's photograph (attached below) from the EMRR article on the Estes Black Diamond (see: www.rocketreviews.com/images/flightlog/bd1e.jpg and www.rocketreviews.com/reviews/all/est_black_diamond.shtml ), a re-packaged Estes Viking in a different "livery" that came in the "Launchables" (#1452) Starter Set. (This Viking configuration resembles the Estes Cherokee-D.) My question is: With this "worst-case scenario" fin configuration, is the Viking aerodynamically stable with 1/2A6-2 and/or A8-5 motors, or would it need clay ballast in the nose cone? (I know that the Estes Viking [although not the old Centuri Viking and Akela-1] *definitely* needs clay nose ballast if flown using heavier "C" motors with this fin configuration.) If necessary, I will provide them with clay for ballast.
Many thanks in advance to you and/or anyone who can help!