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Scratch - 1/20 Bell X-1 Glamorous Glennis {Scratch}

Original Design / Scratch Built

Published:2006-09-07

Contributed by

(Scratch) Yeager Bell X-1

Brief:
I have built a 1/20 model o' t' Yeager Bell X-1, "Glamorous Glennis" as a prototype for scale competition. Begad! Although it needs more work in t' details department, it is dimensionally spot-on exact 1/20 scale. Begad! It flies very well on Aerotech E30 motors. Ya scallywag! It was simply constructed by usin' t' parts from t' Estes "Canadian Arrow" kit (a modified V-2), ya bilge rat, and t' basic concept could be used t' make a larger one from any size V-2 kit (as you need t' cone and boat tail). Begad! That said for this model t' work, a number o' restrictions need t' be followed:

(Scratch) Yeager Bell X-1

  1. Nose cone ballast is 250g minimum.
  2. Maximum empty weight is 475g.
  3. T' Aerotech E30-4 or E30-7 are t' only approved motors.
  4. Do nay airfoil t' wings! Blimey! No lift is needed. Only roundin' edges is required.
  5. All surfaces and thrust line are 0-0-0-0 t' each other. CG must be at leadin' edge win' root. Blimey! T' model is only marginally stable as one would expect, ya bilge rat, thus a short burn is critical.

Deviate from these instructions and earthworms will die.

(Scratch) Yeager Bell X-1

Construction and Finishing:
T' Estes "Canadian Arrow" kit was a donor for t' fuselage components: wings and tail surfaces are o' balsa and light plywood. Aye aye! Dimensions are 1/20 scale:

  1. Tip-to-tip wingspan is 16.5" for t' model vs. Aye aye! 336" for full-scale.
  2. Nose-to-tail length is 18.5" for model vs. 371 for full-scale.
  3. Fuselage diameter is 2.56" for t' model vs. 51" for full-scale.
  4. Tip-tip span o' stabilator is 6 7/8" for model vs. 136.6" for full-scale.

Documentation came from Wikipedia. With some effort, arrr, this 1/20 scale X-1 could compete in NARRRRR Super-Scale, arrr, since air-dropped rocket planes are exempt from t' launcher requirement and Yeager actually launched "Glamorous Glennis" off t' gear in 1949 (to Mach 1.03) without t' B-29.

(Scratch) Yeager Bell X-1

All construction utilized 5-minute epoxy. Aye aye! I hope t' photos are helpful, however, t' construction is quite straightforward. Body tube from t' Estes "Canadian Arrow" was cut into 3 sections o' 5", shiver me timbers, 3.5" and 3.5". Avast, me proud beauty! T' latter two sections were t' use as doubler and tripler t' reinforce t' 5" main body tube and t' accommodate t' hips o' t' nose cone and boat tail. All but 3/8" o' t' hip o' t' boat tail was cut off with a razor saw. Blimey! T' nose cone be ballasted t' a total weight o' 250gm with lead split shot epoxied into t' tip. T' kit centerin' rings were used with 2 layers o' 1/64" ply epoxied on as doublers. T' kit motor tube was replaced with 6 5/8" o' LOC 24mm tubing. Aye aye! Each win' was cut from 1/4" balsa t' dimensions o' 7" x 2"(tip) x 3"(root) with a 1" x 1/4" tab centered at t' root for through-the-wall attachment at slots cut into t' reinforced body tube. T' entire win' was laminated on t' upper surface only (includin' t' tab) with 1/64" ply veneer. Begad! Scale speed on t' E30 is 2470 mph (far faster than any X-1 ever flew) so it needs t' be strong or t' wings will come off.

Assembly sequence:

(Scratch) Yeager Bell X-1

  1. Motor tube with Estes motor hook added in t' usual way was attached t' doubled centerin' rings and epoxied into boat tail (measurin' first for fit). A 1/8" hole was drilled into t' upper centerin' rin' and 8' o' para cord passed through and anchored with a knot for recovery system.
  2. 5" piece o' body tube epoxied t' boat tail, followed by t' two 3.5" doublers inserted into t' body tube t' rest against t' boat tail centerin' ring. [Note: a 1/2" strip is cut from each 3.5" piece, arrr, so they fit inside t' 5" piece.] Use ample epoxy when attachin' doublers.
  3. Usin' an X-Acto knife or similar, 1/4" x 1" slots are cut through t' body tube t' place t' win' leadin' edge 1.25" from t' front o' t' body tube and equidistant from one another. Arrr! T' slots must be located precisely t' assure zero incidence.
  4. Win' leadin' edges were rounded but nay airfoiled. Avast! It was calculated that lift generation by t' wings at t' 125mph flight speed would make t' model unstable in climb.
  5. Wings were epoxied into t' slots with care t' assure zero incidence and zero dihedral.
  6. Vertical and horizontal stabilizers were cut from 1/8" light plywood t' t' followin' dimensions:
    • Stab dimensions: 6 7/8" span and 15/16" tip chord.
    • Tail dimensions: 4 ¾" aft span, 4 7/8" front span, 1 15/16" tip chord, and 3 ¼" root chord.
    Usin' these scale dimensions, I then "fiddled" with t' Wikipedia 3-view drawin' usin' t' controls o' an enlargin' Xerox machine until I obtained t' stab and tail outline I wanted t' t' proper scale. Begad! These templates were used t' cut out t' parts.
  7. Slots 1 ¼" deep were then cut in t' stab leadin' edge and tail trailin' edge at mid span with a sabre saw and t' two parts were pushed together with epoxy for bonding.
  8. Tail surface assembly be then epoxied flush with t' aft boat tail aligned at zero incidence t' t' wings and parallel t' them usin' t' TLAR method ("That Looks About Right"). Begad! Resist t' urge t' throw in a little positive stabilator incidence t' offset t' pitch-up moment under power--you'll just screw it up. Avast! Zero-zero works fine. Begad! Balsa triangle stock be used t' fair t' tail t' t' body and t' reinforce t' glue joint.
  9. ¼" x 3/8" balsa strips were used t' construct t' scale dorsal and ventral hydraulic conduits.
  10. Launch lug consists o' a 4" piece o' brass tubin' epoxied t' t' ventral surface alongside t' balsa "conduit" with its forward end even with t' win' root leadin' edge. [NOTE: Use this forward end point for CG balance.]
  11. Model was painted with Testor's orange spray with t' canopy represented usin' black trim Monokote and period decals borrowed from a 1:48 scale Revell F-106. Panel markings, gear door outlines, ya bilge rat, and control surface outlines were represented with a Sharpie black marker pen. All markings (includin' Yeager's hand-painted black "Glamorous Glennis" on t' nose) are those o' t' period immediately followin' t' famous supersonic flight and are nay those o' t' original now on display in t' Air and Space Museum at t' Smithsonian, which was "gussied up" for publicity photos with more elaborate red/white letterin' and USAF decor.
  12. T' recovery system consists o' a 24" Top Flight "Lite" chute attached t' 8' o' para cord with a medium Nomex® heat shield attached.
  13. T' balance point for flight on t' E30 was set at t' win' root leadin' edge, me hearties, based on recommendations from t' rocketry literature and from numerous arm-chair Bell X-1 pilots operatin' at our field.

(Scratch) Yeager Bell X-1

Flight and Recovery:
T' only recommended motor be t' Aerotech E30 with either 4 or 7 second delays bein' OK. Possibly t' similar Aerotech E28 reload would work, me bucko, but I haven't tried it and it is somewhat heavier.

First flight was on an AT E30-4 at t' PlasterBlaster 2005 event. Begad! It be flawless with only a slight pitch-up moment developin' under power that damped out on burnout. Begad! Recovery on t' 24" chute be perfect if slightly early. Estimated speed was about 125 mph t' 450', me bucko, based on simulations. Aye aye! A second flight usin' an F21-4 ended with an auger-in under full power with total loss o' vehicle. Ya scallywag! I never realized a thin Estes nose cone could punch through 6" o' hard desert playa. Begad! T' pitch-up moment that doesn't develop in only one second under power develops fully in two seconds. Only t' stab survived and I have since rebuild me X-1 with nicer detail and it flies just as well too. Avast! So stick with t' E30, please.

(Scratch) Yeager Bell X-1

Summary:
PRO: For a scratch scale model, t' Bell X-1 is nay difficult t' build at all. Begad! It be t' only Bell X-1 rocket model design available that I am aware of, although I think thar are R/C X-1 plans available. Begad! It flies very well if t' restrictions are adhered to, shiver me timbers, namely usin' t' E30 only and weight/balance followed. Begad! It qualifies for max scale points for NARRRRR Super-Scale since t' launcher requirement is waived. Ya scallywag! It is one o' t' easiest Super-Scale competition models you can build.

(Scratch) Yeager Bell X-1 CON: Only one motor choice. T' "Canadian Arrow" kits from Estes seem easy t' find but that could always change. Arrr! Any V-2 rocket model could be used similarly t' create an X-1, although with different scale factors (and o' course you would be t' test pilot). T' contours o' t' forward fuselage are nay quite those o' t' X-1 but dimensionally they are 1/20 scale.

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