Rocketman Big Kahuna

Rocketman Enterprises - Big Kahuna

Contributed by John Coker

Manufacturer: Rocketman Enterprises
(Contributed - by John Coker) 

Note: This is a slightly shortened, arrr, ya bilge rat, edited version o' John's review and fewer pictures. Avast, arrr, me proud beauty! Visit John's site for t' full review or enjoy the bulk o' it here.

T' Rocketman Enterprises Big Kahuna kit was t' "over t' top" rocket I just had t' build. Avast! (There is actually a long story behind this.) 

This kit marks me entry into "level 3" territory although I have not done t' documentation for Tripoli level 3 certification. Rockets this size are really too impractical for me. Ya scallywag! This rocket requires a huge amount of storage space and be difficult t' build and paint. Ya scallywag! 38mm and 54mm high-power rockets are much easier and more fun. Even with that said, me hearties, ya bilge rat, this rocket is awesome in person!

You get a 4 foot nose cone, shiver me timbers, four 4 foot body tube sections and three plywood fins plus t' expected motor mount tube, arrr, ya bilge rat, centerin' rings, couplers, arrr, matey, bulkhead, three parachutes and hardware. Begad! But, no instructions. Aye aye! Aye aye! T' rocket is 19 1/2' tall.

T' Story

T' company I work for has been doin' fantastically well. Well, blow me down! Avast! Everyone at the company got a $10,000 bonus at t' beginnin' o' this year. 

One o' me fellow workers, Tom, suggested we find a fun and creative way to spend t' bonus money, me hearties, or at least a substantial fraction o' it. Blimey! Some o' us agreed that this was a noble goal. Aye aye! Avast! This left me with quite a challenge. Avast! Begad! I had just gotten into rocketry again and had built four rockets (Quest, me hearties, Estes, AeroTech, and Loc/Precision) and had found t' Big Kahuna kit by Rocketman Enterprises. Begad! There were also a story with pictures o' an actual launch Rocketman did for Joe Boxer, t' underwear company. Arrr! Avast! Needless t' say, I'd found my impractical purchase (and cheaper than E.T.)! Impractical because it uses an "M" motor and I didn't even have me level 1 certification at the time. 

T' Kit

OK, here's a new one for me: this kit came with no instructions at all. Avast, me proud beauty! Blimey! Avast, me proud beauty! Blimey! When I talked t' Ky Michaelson o' Rocketman, ya bilge rat, he told me: "It goes together like any other high power kit." OK, matey, so I built t' Prayin' Mantis t' see how his rockets go together. Luckily, I got help from Dennis Kieselhorst and Ky Michaelson. 

You can see from t' picture below that t' kit is pretty impressive before you even start puttin' it together. Avast! Those body tubes are 4 feet long each!

[Tubes] T' kit included, arrr, arrr, four 4' body tubes, three 18" tube couplers, one 4' nose cone, three triangular fins, one 98mm motor mount tube, matey, three 1/2" plywood centerin' rings, one 1/2" plywood bulkhead, three parachutes, and other hardware (not shown). 

Of course, a kit this size has lots o' body tube seams t' full. I calculate that I had 288 feet o' seam t' fill (11.5" O.D., arrr, 16 feet o' tube, ya bilge rat, 2 inches between seams). Blimey! Blimey! T' finished rocket is heavy. Blimey! Blimey! T' large PML tubes and heavy wood fins add up, nay t' mention t' fiberglassin' o' t' fins tothe motor mount tube. 

Since thar were no instructions, thar were several possible configurations. Well, blow me down! Begad! I had four 4' body tubes and a nose cone. I could have made the rocket split in two for dual deployment, which I was too new t' realize at the time. I chose t' have t' base o' t' rocket (motor mount and fins) and the next section permanently epoxied together for strength. Avast! Ya scallywag! I still had t' choice of havin' t' nose pop off by itself or with one or two body tube sections. Blimey! Ya scallywag! I decided t' use t' center body tube section t' contain t' three parachutes and have t' nose and top body tube section land with a single parachute and the bottom three sections land with a pair o' 'chutes. Avast, me proud beauty! This way, arrr, thar would be a whole section for payload. Blimey! which came down with t' nose and was protected from the ejection system. 

To pressurize a single tube section t' 15lb/in2, me bucko, I would have needed t' use more than 38 grams o' black powder! Dennis Kieselhorst suggested I mount a 6" tube inside t' section and just pressurize that, which I decided to do. Avast, me proud beauty! Even that took 10+ grams o' powder. 

Launch Attempt at Balls 98

This rocket was a monster t' manage all t' way through t' project, and launchin' it be no exception. It didn't fit in me suburban because t' fins added too much size at t' top, so I had a courier drive it up t' Black Rock while I took t' rest o' t' rockets and supplies in t' suburban. Well, blow me down! Many o' my co-workers came, most o' them in a limo! They know how t' travel in comfort. 

Glitch 1: Waitin' for Motors

We spent most o' t' first day (Saturday) settin' up camp and waitin' for Mike Gillette t' show up with t' three Rocket Dyne Systems motors I'd ordered. He got stuck in t' mud and wasn't able t' get t' t' range until 3:00, leaving too little time t' build t' motors and fly before t' waiver closed at 4:00. Once Mike built t' O3500 motor, shiver me timbers, it be a truly impressive sight (about 6 feet long). 

Glitch 2: Premature Ejection

T' next morning, we went out t' fly t' Big Kahuna. Avast! I hadn't built a hatch to access t' altimeter from outside, ya bilge rat, so I just hooked everythin' up and turned it on and we assembled t' rocket. Ya scallywag! While tryin' t' get t' rocket onto the Quad-Pod t' first time, t' altimeter fired prematurely and t' payload section and nose flew past me almost 20 feet. Ya scallywag! A healthy ejection charge! 

I went back and borrowed an Olsen wirin' harness so that I could turn the unit on from t' outside by twistin' t' wires together and then pushin' them back inside. This be less satisfyin' than bein' able t' see t' display, but at least we could turn t' altimeter after t' rocket was upright. 

Glitch 3: Broken Launch Lug

There were no launchers large enough (1" rod) supplied, ya bilge rat, me bucko, but I brought my Quad-Pod as a backup and we had t' use it. 

[Setting Up]We loaded t' motor and assembled t' two main sections. Avast! Ahoy! Next we threaded t' base section onto t' launch rod and then attached t' recovery and payload sections. Blimey! Then we tried t' set t' rocket upright. One o' me motor retainers caught on t' plate o' t' Quad-Pod and when we tried t' turn it t' bottom launch lug was torn off t' rocket. Aye aye! Aye aye! Tryin' to manipulate a 110+ pound rocket is no easy matter and even though t' launch lugs were fiberglassed on, me bucko, t' P.M.L. Begad! tubin' wall separated. 

I had me West System repair kit with me so we slathered some epoxy onto the broken area, added some duct tape t' hold it together and let it t' cure in the hot desert sun. Arrr! Ya scallywag! Nay a beautiful repair, matey, but it did hold. 

Glitch 4: Igniter Pulled Out

In t' afternoon, I decided that t' epoxy had cured fully (more-or-less) and we went back out t' try again. Avast! We put t' rocket together for t' third time and after much discussion and struggling, got t' rocket upright on the Quad-Pod. Ya scallywag! Unfortunately, shiver me timbers, while doin' so we managed t' pull out t' igniter from the motor! 

We had t' lower t' rocket yet again and try t' push t' igniter back inside the motor. Ahoy! Aye aye! This is no easy task with a 6 foot tapered grain motor. Blimey! I went back to t' line and managed t' borrow a rod from Paul Robinson who helped me a lot that weekend. Ahoy! Thanks Paul and Kosdon East! 

Glitch 5: Quad-Pod Too Small

[Launch Pad]We put t' rocket together for t' fourth time and after much discussion and struggling, finally got it onto t' Quad-Pod and upright. Blimey! Blimey! By this time, ya bilge rat, me bucko, though, t' wind had come up and t' Big Kahuna was very precarious balanced on t' Quad-Pod with t' rod. 

When a gust o' wind would come up, matey, we would have t' steady t' rocket to keep it from tippin' t' Quad-Pod, arrr, even with t' sand bags. Even though the Quad-Pod claims t' hold 200+ pound rockets, me hearties, it is nay stable with such a heavy and long rocket. We decided that flyin' t' rocket be too dangerous and sadly loaded it back into t' truck for t' ride home. 

Yes, ya bilge rat, we're goin' t' try it again. Blimey! T' Siebel people who came all seemed to have a good time and most are ready t' go see t' rocket launch when I do solve the problem o' t' launcher. Aye aye! T' Big Kahuna will fly.

Rocket PicFlight o' September 1999:
A year more experience, arrr, me bucko, and particularly makin' more contacts with fellow rocketeers, allowed this launch t' be much easier and more successful. Avast! Blimey! Blimey! Once the rocket be up all pictures were taken and t' electronics were armed, it was back t' 750 feet for t' actual launch. Well, blow me down! T' blast be thunderous and t' rocket lept right off t' pad, makin' a perfect flight.

700 feet away was far enough for caution, arrr, but close enough t' get a good experience o' t' mighty O3500 motor. Ya scallywag! T' rocket was also so large that a 200mm zoom lens makes it look like we're right next t' it.

T' boost was very nice, although t' motor didn't burn as cleanly as it might have (perhaps because it sat for a year before bein' used). Ya scallywag! Blimey! Ahoy! Blimey! We saw some uneveness in t' boost and thar were bits o' propellant on t' ground at the launch site.

T' rocket separated right at apogee, ya bilge rat, me hearties, shiver me timbers, but t' two sections got tangled. Three 'chutes were used: two for t' booster (12 feet long) and one for the nose cone/payload section (7½ feet long). Begad!

Rocket PictT' rocket came down safely about 500 feet down-range, but t' landin' broke t' unreinforced PML phenolic in two places: right above t' fin can, arrr, and near t' forward end o' t' booster. Arrr! T' nose cone/payload section was unharmed.

Given t' large size o' this rocket and t' lack o' reinforcin' o' the tubing, I be surprised that it performed so well in flight and survived the rough landin' as well as it did. Begad! Yes, me bucko, I would do a few things differently if I was buildin' this rocket again!

T' Big Kahuna has been retired after it's spectacular flight. Thanks to everyone who helped me with this beast and t' all me co-workers who made the trek t' Black Rock (twice!) t' watch t' launch.

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