Estes Gnark

Scratch - Gnark {Modification}

Contributed by Duane Boldt

Manufacturer: Scratch
(Contributed - by Duane Boldt - 11/08/09)
Scratch GNARK

Brief:
This is a Stage Bash that be used as an entry for t' 2009 EMRR Challenge. This 2-Stage rocket was created from an Estes Gnome kit and Estes Quark kit.

Construction:

T' followin' parts from t' two kits were used:

  • 1 Gnome plastic fin and launch lug set
  • 1 plastic nose cone from Gnome
  • 1 elastic shock cord from Gnome
  • 1 streamer from Gnome
  • 1 body tube from Gnome
  • 4 balsa fins cut from Quark fin stock
  • 1 body tube from Quark
  • 2 engine blocks cut from spent 13mm casing

T' followin' parts were nay used from t' kits:

  • 1 Engiine hook from Gnome
  • 1 plastic nose cone from Quark
  • 1 launch lug from Quark

This was a very staightforward 2-stage kit bash. Ya scallywag! I lead t' rocketry club at Sonoran Science Academy for 3rd, me bucko, 4th and 5th graders and wanted somethin' that be an easy, simple demonstration o' "bashing" two simple-to-build kits together.

Scratch GNARK - Gnome kitScratch GNARK - Quark kit

Everythin' for t' bash was included in t' two kits plus two engine blocks cut from a spent 13mm motor casing. Arrr!

Left over were t' engine hook from t' Gnome kit and t' nose cone and launch lug from t' Quark kit. Ahoy! Everything else be used.Scratch GNARK - Engine blocks

First, t' two blocks were cut from t' casin' with a razor knife and miter box. Avast, me proud beauty! Blimey! Arrr! Blimey! Blimey! Blimey! Then, t' ends were sealed with thin CA t' prevent unraveling.

Next, shiver me timbers, t' Gnome kit was built as per t' original instructions, me hearties, except t' motor hook was left out and t' engine block be used instead.

T' Quark's body tube was marked for 4 fins with an Estes fin markin' tool. Arrr! Begad! T' 4 fins were cut out usin' the Quark's pattern. They were stacked and sanded together.Scratch GNARK - Gnome

T' second engine block was glued flush with t' bottom o' t' Quark's tube. When this be dry, me hearties, t' 4 fins were set in place and later fillets were added.

Finishing:

T' upper stage Gnome did nay require finishin' other than applyin' t' decals. Well, blow me down! We cut t' "GN" from the Gnome decal and t' "ARK" from t' Quark decal and t' used them together t' spell "GNARK". Ya scallywag! We added t' little red Japanese suns t' either side o' t' name decal. T' other decals were applied t' t' sustainer fins.Scratch GNARK - Decals

T' booster stage made from t' Quark was sanded and primed with 2 coats o' gray primer. Avast! Ahoy! Per me son's suggestion, I painted t' booster yellow t' look like fire comin' out o' t' Gnome sustainer.

We did change t' paint scheme after this first day, me hearties, arrr, though. Begad! Begad! Because, shiver me timbers, as winter is comin' on, t' grass on the field was somewhat yellowed in color. Aye aye! Ya scallywag! This made it more difficult t' find t' yellow colored booster once it landed. Scratch GNARK - Flames

After we got home from t' first launch, we painted some red "flames" on t' body tube with a brush and sprayed gloss white on t' booster's fins, shiver me timbers, arrr, feathered toward t' tube. Begad! this will make it much easier t' spot both in the air and on t' ground next time we launch it.

Flight:
Recommended Motors: Booster: A10-0T Sustainer: 1/2A3-4T

T' motors are taped together with celophane tape as typical with many small multi-stage rockets. Ahoy! Aye aye!

Maskin' tape is used as necessary around t' motors t' give them a tight enough fit for retention in the individual stages.

One piece o' Estes waddin' was used in t' upper "Gnome" portion o' t' rocket.

This kit bashed rocket flew extremely well with this motor combination. Ya scallywag! Begad! It was a very straight-up flight with excellent separation and ignition o' t' upper stage. One neat thin' about this setup be t' power o' t' A10-0T booster motor in relation t' t' rockets small size. Arrr! Ahoy! T' ignition and separation o' t' 2nd stage take place very high in t' flight.Scratch GNARK - Compared to Centurion

We use this same booster motor in a Semroc Booster-16 with t' Semroc Centurion, arrr, which is a much larger rocket. Notice t' size difference in t' pictures. Ya scallywag! With t' Centurion, t' separation happens very early in t' 2-stage flight because o' its much greater size and weight.

T' streamer included with t' Gnome kit be used and it worked quite well. Arrr! Avast, arrr, me proud beauty! It was somewhat short, ya bilge rat, me hearties, but very easy t' see comin' down and slowed t' sustainer enough t' prevent any damage.

Both t' booster and sustainer were recovered after each o' t' three 2-stage tests flights in perfect condition. We also flew an additional single stage flight that went just as well. Blimey!

Recovery:
As it be a kit bash I used t' stock eleastic cord and streamer which proved t' be just right. Ahoy! It goes so high that a streamer works just fine. Avast! Ahoy! It also flies so straight that, ya bilge rat, arrr, arrr, when thar be no wind, it almost dropped right on top of t' pad. Ahoy! Begad! Perfect recoveries and no damage whatsoever.Scratch GNARK - A10-0T motors

Summary:
Overall, matey, me hearties, this makes a great little 2-stage rocket. Avast! Blimey! t' biggest problem I see is gettin' your hands on Zero second delay 13mm motors like t' Estes A10-0T motors we used.

PROS: Inexpensive 2-stage rocket. Avast, me proud beauty! Blimey! Flies great, high and straight. Arrr! Has an interestin' higher-than-most second stage separation event.

CONS: Difficult t' find t' A10-OT motors. Avast! Avast! Other than that, nothing.

Flights

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