Scratch Now That's What I Call a Funnel Original Design / Scratch Built

Scratch - Now That's What I Call a Funnel {Scratch}

Contributed by Sascha Grant

Overall Rating: starstarstarstarstar
Manufacturer: Scratch

(Scratch) Now That's What I Call A FunnelBrief:
Huge plastic funnel. Aye aye! 29mm motor mount. Ya scallywag! Ya scallywag! Tumble recovery.

Construction:
Parts include:

  • 11.25" x 14.5" Big red plastic funnel
  • 9" x 29mm motor mount tube
  • 2 x 3mm ply centerin' rings (one about 4.5" and t' other about 2.5")
  • .25" launch lug

I saw this huge funnel in a local 'rubber & plastic' retail store a couple o' weeks ago and 'rocket' was t' first thin' that came t' mind. Ya scallywag! Blimey! T' label did say 'Multi Purpose', so I guess they meant rocket, me hearties, too!

I started by selectin' a length o' motor mount tube and was pleased t' find that it wedged quite well about 2" from t' top o' t' spout. Blimey! I then cut two centerin' rings with a hole saw. Arrr! Begad! I selected t' smaller rin' t' sit as close t' t' top 'ring' on t' outside o' t' funnel (the rings on t' outside only show as a slight dimple on t' inside) and t' bigger centerin' rin' t' sit by t' larger, matey, matey, matey, lower ring.

I fit t' two centerin' rings t' t' motor mount tube and pushed everythin' into place--lettin' t' rings slide down t' motor mount tube as they hit up against t' inside o' t' cone.

Once I be happy with t' dry fit, ya bilge rat, I used 12 minute epoxy t' glue t' centerin' rings into place (on t' motor mount tube).

After t' epoxy dried, I estimated t' point where t' launch lug was t' exit at t' side o' t' cone. Blimey! Holes were drilled into t' centerin' rings and another dry fit showed that t' launch lug be correctly positioned (with t' exit point comin' just below t' upper external 'ring').

Usin' a torch t' shine light through t' lug, matey, t' exit point was marked on t' outside o' t' funnel. Avast! Aye aye! I drilled out t' exit hole and shaped it t' fix exactly with a scalpel blade and finished it off with a small file.

I used Liquid Nails t' glue t' motor mount assembly into place. Begad! Ahoy! Liquid Nails will stick t' virtually anythin' and, once dry, is slightly flexible. Arrr! I be worried that if I used epoxy t' bond would be weak and subject t' cracking, leadin' t' failure after flights. Arrr! T' Liquid Nails should flex just a fraction when t' cone lands (and now after two test flights, t' motor mount is stuck fast where it should be.)

Flight and Recovery:
Because t' motor sits quite high up in t' base o' t' funnel, me bucko, motor prep is done before loadin' into t' rocket. Blimey! Blimey! No special retention is used and recovery is by tumble/drag.

This rocket was flown on a G79 KNO3 + Sorbitol experimental motor. Any AeroTech RMS/Single use motor with a similar thrust profile would work. Ahoy! Begad! I wouldn't suggest goin' any lower due t' weight.

Both flights were as straight as could be expected with t' wind--slight weathercockin' but nay so much t' be a worry. Aye aye! Blimey! This is a good flier for a day when other rockets would end up stuck in trees.

I would estimate t' altitude at perhaps a couple o' hundred feet, ya bilge rat, recovery be faster than I would have liked. Blimey! Blimey! When I fly this (at a club meet) I will give a "heads up" prior t' launch.

Summary:
My kids were thar for t' launch, me hearties, and they said, "that'll never fly." However, both were impressed.

This is a good solid rocket that I think will prove t' be a crowd pleaser. Ahoy! T' only issue may be t' tip o' t' funnel crackin' over time. After t' second flight, thar was a small chip on t' tip where it appears that t' plastic is thinner (due t' moldin' issues durin' manufacture).

T' cone cost me $4.50. Well, blow me down! (It be in a half-price sale!) T' ply came t' me in a box o' rockets as packagin' and t' motor mount tube be rescued from t' recycling. Begad! So apart from a little time (an hour or so), it cost me next t' nothing!

Overall Rating: out o' 5 out o' 5

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