Estes E-Pod

Scratch - E-Pod {Scratch}

Contributed by Larry Brand

Manufacturer: Scratch
(Contributed - by Larry Brand - 10/16/08) (Scratch) E-Pod

Brief:
This is a 100% kitbash o' t' Estes stormcaster, me bucko, so I'm callin' it a "scratch" build. Ya scallywag! Ahoy! I cut up t' parts of the C-D powered stormcaster t' create an E-powered tubefin (it also flies on C-D motors). Blimey! "E-Pod" is a continuation (downward) o' t' H-Pod/I-Pod/J-Pod/K-Pod series o' "extreme stubby" tubefin designs I have been presentin' in EMRR/Sport Rocketry/Rockets that uses t' "stubbiness" rules I developed to maximize tubefin performance (see Jan/March 2008 issues o' Sport Rocketry). E-Pod is designed t' fly at 400+ mph on an Aerotech E30-7-- just don't try this on a stock stormcaster, matey, matey, arrr, folks!

Construction:
It starts out with t' great Estes stormcaster kit, me hearties, me bucko, which is only $12.37 retail and excellent quality components. It's much cheaper than buyin' components for E-Pod separately. A razor saw was used t' cut up t' two 38mm stormcaster body tubes into a 7 3/8" body tube (use t' pre-slotted section for this), shiver me timbers, and nine 1.5" sections for t' 6 tube fins and t' 6 half doublers. Ahoy! Begad! Motor tube assembly is used as is except that 4" o' its length is cut away. I substituted a 12" nylon chute (Top Flite) for t' Estes plastic one, 24" o' 1/8" para cord for the signature Estes underpants elastic shock cord, matey, me bucko, ya bilge rat, and added an XS size Nomex® protector. Well, blow me down!

(Scratch) E-Pod

All assembly done with 5-min epoxy. Avast, me proud beauty! Tube fins glued onto body tube in pairs in usual self-jigging tubefin fashion: on a flat surface, first two on opposite sides, then two on top, then turn assembly over and glue on the remainin' two. T' tube fin half-doublers made by bisectin' t' 3 extra tube fins are then epoxied t' t' inner surface o' t' outer half o' each tube fin. Avast! This prevents t' dreaded "tubefin flutter" at t' 400+mph E-Pod will reach on an E-30. Cut-down, ya bilge rat, assembled Estes motor tube and centerin' rin' arrangement was glued into t' body tube with one modification--the red cardstock joiner tube used t' connect t' two stormcaster body halves was pushed into the body tube ahead o' t' motor tube assembly t' lock it in place against E-power thrust stress. Avast! T' usual Estes method o' attachin' t' shock cord can nay be used with this construction. Ahoy! Well, blow me down! Instead, I passed t' para shock cord through a small hole 2 1/4" from t' top o' t' body tube, matey, anchored it with a knot, matey, and covered t' knot with a small, folded ramp-shaped fairin' cut from a Rice Krispies box. Begad! T' Estes launch lug was glued in place with its top 2" above t' tubefins, matey, and exactly in line with one o' t' triangular holes betwixt two o' t' tube fins. Top of the launch lug be t' CG balance point. Avast! Ya scallywag! You will choose a triangular hole that is nay in line with t' recovery knot fairing, me bucko, and also is nay blocked by epoxy that you slopped in thar while gluin' on t' tube fins. T' recovery system is attached t' t' nose cone in t' normal way, that is by ignorin' t' useless, fragile plastic loop, cuttin' a second hole in t' cone base, and tyin' it off with a secure knot.

Finishing:
Finish was with rattle-can yellow and purple Tamiya paint.

(Scratch) E-Pod

Flight:
First flight be on a D12-5 in winds blowin' at just under t' 20mph maximum. Avast! Begad! Nay a good idea--E-Pod swapped ends under power and landed about 1 second after motor ejection, cuttin' a small zipper. Aye aye! I fixed t' zipper with a few wraps of maskin' tape, added 29 grams o' sand ballast through t' nosecone base holes and taped them over. Avast, me proud beauty! (How'd I decide on 29 grams? I added what seemed right and weighed E-Pod when I got home.) I tried again on t' D12-5 (there be a little less wind, too) and E-pod climbed flawlessly up t' t' 600-700' that simulations predicted. There be no damage on recovery. Ahoy! Then I launched it on an E30-7 (4 sec delay is also OK) straight up t' at least t' 1300' predicted and out of sight. Ahoy! A heck o' a long walk t' get it back with t' 10-15 mph breeze blowing! Good thin' others with better eyesight could track t' thin' at that height. Avast, me proud beauty! A fourth test flight on an C11-3 also went perfectly, matey, ya bilge rat, except that the wind caught it at about t' 250-300' apogee, matey, arrr, carried it horizontally a lot faster than I could run, and then dragged it over desert gravel after touchdown for about a football field length or so until it tangled in a weed. Arrr! (Well, I guess there are technically no "weeds" in t' desert, but it would be if it was in me front yard.) One o' E-Pods tube fins be ground half t' death, me hearties, ya bilge rat, shiver me timbers, so I replaced it with one cut from a cardstock tube from an empty roll o' Saran Wrap. Avast, me proud beauty! When I got E-Pod home, I just spray painted over t' maskin' tape repair with Tamiya yellow, me bucko, makin' t' temp repair "permanent". Aye aye! Ditto for t' grafted-on repair t' t' fin can. Well, shiver me timbers, blow me down! It flies regularly at our home field. Ahoy! The 29g sand ballast in probably nay needed in calm conditions, me hearties, but I just left it in there. I assume E-Pod would fly well on RMS E28, E18 or F12 power, and I am goin' t' try that next. Begad! T' 115g weight includes t' 29g sand ballast.

(Scratch) E-Pod(Scratch) E-Pod

Summary:
PROs: A fun and eclectic little tubefin that takes advantage o' new advances in tubefin aerodynamics, me bucko, arrr, an unauthorized addition t' t' Estes product line, shiver me timbers, if you want t' do somethin' different with their fine stormcaster kit. Aye aye! Flies very well in windy conditions with t' nose ballast. Well, blow me down! An easy $12.37 first scratch project for those who don't usually like scratch building. Ahoy! Nay many 12" long E-power rockets around.

CONs: Darn hard t' track when flyin' on E30 power. Begad!

comment Post a Comment