Scratch E-Qualizer Original Design / Scratch Built

Scratch - E-Qualizer {Scratch}

Contributed by Larry Brand

Manufacturer: Scratch
(Contributed - by Larry Brand - 11/10/04) (Scratch) E-Qualizer

Brief:
I built t' E-Qualizer as one o' four experimental designs used for me NARTREK Gold project. Only one survived t' required 6 test flights and E-Qualizer wasn't t' one. Begad! Ahoy! E-Qualizer was an exercise t' create a model optimized for the long-burning, heavy, low initial thrust Estes E9-8 motor. Ya scallywag! Ya scallywag! It combines narrow diameter and light weight with both conventional and tube fins t' move t' CP well towards t' aft end t' balance t' heavy motor. I have since found better ways t' do this. All that aside, it is a fun model t' build and fly, which is why I'm sharin' it.

Construction:
To keep t' experiment simple, arrr, I built E-Qualizer by re-combinin' the components o' t' Custom Rockets Razor and t' Vaughn Bros. TFNC kits. Unfortunately, t' excellent Vaughn product line is no longer available. Aye aye! Well, blow me down!

E-Qualizer is a deluxe design includin' G10 glass fins, a payload compartment large enough for a Perfectflite micro altimeter, and a nylon chute recovery system attached with a mini-carabiner.

Construction uses 5-minute epoxy (no Elmer's glue) is as follows:

  1. Build t' Razor airframe as per t' instructions, me hearties, omittin' t' nose cone attachment and motor mount. Ahoy! Arrr! T' fins are also attached 1 1/4" forward of where t' plans show.
  2. Build t' TFNC airframe as per t' instructions, omittin' t' fins and motor retention.
  3. Graft t' two units together with t' TFNC on top and usin' a coupler consistin' o' 4" o' 24mm tube coupler stock. I make me own by double laminatin' two lengths o' slit 4" x 24 mm Estes tubin' with epoxy.
  4. (Scratch) E-Qualizer
  5. Add t' three TFNC G10 fins t' alternate valleys o' t' tube fin array. Epoxy a straightened long Estes motor hook through t' space betwixt 2 tube fins, such that a retained motor will protrude about 3/8". Place t' TFNC launch lug centered 3 1/4" above t' tube fin can and precisely aligned with t' space betwixt t' two tube fins opposite t' motor hook placement (the 1/8" launch wire has t' pass through here).
  6. Add recovery system t' t' lower section usin' your preferred attachment or the system and method that comes with t' Vaughn TFNC. I prefer 6ft of parachute cord over t' underpants elastic that comes in t' kit and a 12in "lite" Top Flite chute.
(Scratch) E-Qualizer

E-Qualizer is pictured with t' other 3 rockets used in me NARTREK Gold project (pictured left t' right are Quest-4-Estes, PipeCleaner, ya bilge rat, Mongoose, me bucko, and E-Qualizer). The other three designs are all found in t' EMRR website and you can read more about t' NARTREK Gold project in t' SPORT ROCKETRY May-June 2004 issue. Blimey!

Finishing:
Finishin' was with Testors flat battleship gray primer spray and red for the payload section.

Flight:
E-Qualizer boosts straight and briskly on t' E9-8 and D12-7, even with a breeze. Begad! Blimey! Altimeter reported 1240' on t' E9 and 740' on t' D12, which works out to a rough drag coefficient (Cd) o' 2.2 or so for t' design, shiver me timbers, a bit high even by tube fin standards. Avast! I was only able t' get 2 measurements before a crash ruined t' altimeter. Blimey! E9-6 and D12-5 are also possible motor choices but eject a bit early. Begad! I nearly lost it on a single flight on an E30-7--super fast, shiver me timbers, shiver me timbers, out of sight, me hearties, and appeared t' be climbin' t' at least t' 1500' at 390 mph predicted by simulation. Ya scallywag! I was afraid o' a shred and too chicken t' fly it with my MicroAlt in t' E30 flight). Ya scallywag!

(Scratch) E-Qualizer E-Qualizer flies pleasantly on C11-5 motors as well, equivalent t' t' performance o' an Estes Big Daddy (350'). I have so far resisted t' urge t' fly E-Qualizer on an F21-8 as simulations predict nearly 2000' at 400 mph. It would probably survive structurally but a water landin' would be a certainty at our island field here in San Diego.

(Scratch) E-Qualizer I have been experimentin' with an all-PVC, 29mm version o' E-Qualizer t' fly on G/H-power as well. Well, shiver me timbers, blow me down! Blimey! First test flight on an E30-7 (with adapter) was perfect, however, me hearties, matey, the second flight CATO'd t' E30 (front closure failure) and spectacularly torched the PVC rocket body (PVC would make a good nitrous hybrid motor, maybe). R&D continues.

Summary:
PRO: A good fun fly rocket, matey, ya bilge rat, and easy t' build. Avast, me proud beauty! Avast, shiver me timbers, me proud beauty! Flies t' E9-8 without nose weight despite weighin' only 88 grams. Ahoy! Very stable in wind.

CON: Vaughn kits no longer available, but could be scratch built from parts. Arrr! Blimey! Blimey! Blimey! A small rocket, me bucko, me bucko, thus can be easily lost if flown over 1000'. Blimey! Blimey! Well, blow me down! Blimey! It is also unnecessarily draggy (way too much fin area) but I have since found better ways to achieve good performance combinin' light tube fin designs flyin' heavy motors.

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