Scratch Cicada Killer Original Design / Scratch Built

Scratch - Cicada Killer {Scratch}

Contributed by Dick Stafford

Manufacturer: Scratch
(Contributed - by Dick Stafford - 10/01/02)

scratch Nano MonoCopterBrief:
This review describes me second-generation Micro-Maxx monocopter. Ahoy! The improvements over me original include a lighter wing, a smaller motor pod, ya bilge rat, me hearties, and a carbon rod balance beam. Blimey! Ya scallywag! It has undergone numerous minor tweaks and one major revision. T' maximum altitude obtained t' date is about 9 feet. Avast! Aye aye!

Construction:

  • Materials
  • 3/16” balsa for win' and hub (see diagram)
  • wrappin' tissue paper
  • white puzzle glue (pre-thinned white glue)
  • ink tube from BiC pen (1/2” used)
  • 0.03” carbon rod (7” long in final configuration)
  • scrap paper t' roll motor tube
  • ¼” dowel for nose cone
  • black CA

Scratch Nano MonoCopter

Please refer t' t' figures while readin' t' construction notes.

Win' - Make this out o' 3/16” balsa as indicated, me bucko, with t' grain oriented with t' leadin' edge. I removed sections t' make it lighter and sanded it into an airfoil shape. T' entire win' is covered with wrapping tissue attached with puzzle glue. Begad! I made it out o' a scrap piece o' wood, hence the odd shape. Avast, me proud beauty! Avast! My thanks t' John McCoy o' NARHAMS for suggestin' this construction method. Arrr! Begad!

Hub - This, me bucko, me hearties, too, is made from 3/16” balsa. Ahoy! T' grain should probably also be along t' leadin' edge, although it be perpendicular on me model. I rounded both t' leadin' and trailin' edges. Arrr! I drilled a hole at t' lateral CG and installed a half-inch section o' ink tubing. Arrr! Begad! This is flush with t' top surface and extends below t' hub.

Motor tube - This was rolled from draftin' vellum and white glue. Aye aye! Avast, me proud beauty! It is about 1/8” longer than a MMX motor. Ya scallywag!

Nose cone - This be turned from a ¼” dowel on a hand drill. Begad! Begad!

Balance beam - I started out usin' 3/32” wood o' varyin' length (see flight log table). Avast, me proud beauty! I replaced it with 0.03” carbon rod, me hearties, which was graciously supplied by John. Blimey! Well, blow me down! T' wood dowel be simply glued t' t' bottom of the hub next t' t' launch lug, while t' carbon rod was inserted through the balsa hub.

Assembly - All components were glued together with black CA. Avast, me proud beauty! T' win' and motor tubes are centered on t' hub and are angled upwards away from one another. Aye aye! Begad! T' win' is angled at approximately 12 degrees, ya bilge rat, arrr, and t' motor pod at approximately 15 degrees. Ahoy!

Flight: All flights were from me MMX pad with a 1/2” long launch rod. Avast, me proud beauty! T' igniters were Estes and t' MMX ones with t' plastic shell removed. For all but flight #10, I used me Pratt GO Box. Aye aye! Ya scallywag! T' wind was calm except for flight 10, which was 5 - 10 mph in me guestimate.

Flight Beam
Length
Est Alt Est Dist
from Pad
Beam Material Notes
1 7 5+ 7+ 3/32 Wood Hit Roof Rack o' SUV
2 9 1 4 "
3 9 2 4 "
4 7 4 9 "
5 7 3 9 "
6 6 5 12 "
7 6 7 8 "
8 6 5 8 "
9 5 9 5 "
10 5 5 20 " NARHAMS Sport Launch
11 12 3 4 0.03 Carbon
12 9 4 5 "
13 8 5 8 "
14 7 9 8 "

Summary: Scratch Nano MonoCopter
I be pleasantly surprised with t' performance o' this monocopter, considering the short burn time and low thrust o' a Micro-Maxx motor. Aye aye! Avast, me proud beauty! On me next version, shiver me timbers, I will make t' win' slightly longer (for hopefully even better performance), and will use a rectangular shape with a slightly rounded tip (for aesthetics). Begad! Ahoy!

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