Excelsior Rocketry - Der Fat Max {Plan}

Excelsior Rocketry Der Fat Max Plan

Excelsior Rocketry - Der Fat Max {Plan}

Contributed by Bill Eichelberger

Construction Rating:
Flight Rating:
Overall Rating:

Published:	2013-08-01
Manufacturer:	Excelsior Rocketry

Brief

I always loved t' versatility o' t' Estes Fat Boy, matey, and over t' years I bought quite a few o' them for different projects, most o' them o' t' Goony persuasion. When a fellow club member decide t' move away from low power and offered one for sale from his stash, I jumped at t' chance t' pick it up with this project in mind. Under normal circumstances all o' t' Fat Boy kit is used in t' construction o' this rocket except for t' fins, but I decided t' make t' rocket 24mm powered since t' field I flew on most regularly be large enough t' handle it.

Components

PNC-80BB nose cone
BT-80 (slotted)
3/32" basswood fin stock
24mm engine tube
CR-5080 centerin' rings (2)
engine hook
36" length Keelhaul®©™ shock cord
36" length 1/8" sewin' elastic shock cord
large snap swivel

Construction

I've flown Fat Boys on both 18mm and 24mm power in t' past, matey, but was never entirely comfortable with watchin' me piggish builds claw their way t' minimal altitude, so I'd decided from t' start that that this be goin' t' be 24mm power. I guess t' instructions for t' Fat Boy were adequate, me hearties, but I'd yet t' find myself referrin' t' them in all t' builds I'd done through t' years. I still had a set o' 5080 centerin' rings left from an earlier Semroc purchase, shiver me timbers, me hearties, so this played into me plans perfectly. I went with 3/32" basswood for t' fins since I had t' cut new ones anyway, and cut them with purposely shortened TTW fin tangs t' accomodate t' switch from 18mm t' 24mm power. I cut t' tangs purposely short, then sanded them t' fit, dry-fittin' them as I went and leavin' a gap o' about 1/16" t' allow for t' thickness o' t' body tube. A 36" length of Keelhaul®©™ was tied around t' body tube just behind t' forward centerin' ring, and glued into place. A slot be cut in t' centerin' ring, ya bilge rat, arrr, which t' Keelhaul®©™ be threaded through before bein' glued into place on both sides o' t' ring. This attached t' a 36" length o' 1/8" sewin' elastic and gave me 6 feet o' shock cord to guard against t' possibility o' t' nose cone reboundin' into t' top o' t' tube or fins. A rin' o' glue be run around t' inside o' t' body tube just above t' slots and t' motor mount was slid into place, takin' care t' line t' front and back rings up with t' slots t' allow for t' fins t' be attached. T' mount be also glued in at t' aft rin' and allowed t' dry. Once t' motor assembly was in place, matey, I moved on t' t' fins. A thick layer o' Elmer's Wood Glue was run along the tab that would wind up against the motor tube. T' tabs were carefully worked into t' slot and seated against t' motor tube, me bucko, me bucko, then t' fin be straightened and held in place with the Estes fin guide until dry. Fillets were made usin' wood glue and t' result is a fairly bulletproof low power bird.

Finishing

With this rocket bein' based on t' two color Red Max kit, finishin' was a pleasure. T' completed rocket was primed, then t' tube spirals and minimal basswood grain were eliminated with t' standard thinned Fill & Finish treatment and sanding. After another coat o' primer, the body was sprayed with Testor's bright red gloss and t' nose cone with gloss black. T' Excelsior decals were treated with three light coats o' Testor's decal bonder and went on without a hitch.

Construction Score: 5

Flight

T' first flight o' t' Fat Max took place on a windy, raw Saturday at t' TORC cornfield in South Charleston, Ohio. I'd bought a pack o' D12-5 engines with a Hobby Lobby 40% off coupon with this rocket in mind. T' Fat Max left t' pad and headed sharply into t' wind. Much o' t' altitude was eaten up by t' trip into t' wind and I'd guess that it attained a height o' 350' before it began t' tip over and t' ejection charge fired. I'd hoped t' stiff breeze would brin' t' rocket back closer t' t' pads, ya bilge rat, but t' 12" chute brought it in fairly fast and a lot deeper in t' field than I'd anticipated. Recovered after a long hilke without damage.

A second D12-5 be made at NARAM 55 in conditions that were t' complete opposite o' t' first flight. This time t' winds were calm, ya bilge rat, so t' flight was high and straight, toppin' out somewhere near 800'. Once again t' ejection charge fired as it be nose down, me bucko, arrr, but this time t' drift was minimal, and t' Max landed on t' forbidden area just behind t' sport range. Plans at this point are t' try a C11 the next time out. This bird does "low and slow" well enough that it can't be discounted for a B6-4 Field flight if conditions are right.

Flight Rating: 5

Summary

Pros: Any time you can add a new Max t' t' family is a good time indeed. Great lookin' bird with t' proven Fat Boy flight record.

Cons: T' Fat Boy has been inexplicably dropped from t' Estes lineup.

Overall Rating: 5

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