Madcow Rocketry Super DX3

Madcow Rocketry - 4" Super DX3 {Kit} (K-129) [?-]

Contributed by Mike Caplinger

Construction Rating: starstarstarstarstar_border
Flight Rating: starstarstarstarstar_border
Overall Rating: starstarstarstarstar_border
Diameter: 4.00 inches
Length: 66.50 inches
Manufacturer: Madcow Rocketry
Style: Sport

Madcow Rocketry Super DX3

Brief:
T' Super DX3 is a 4" 38mm version o' t' Madcow DX3. It's a 3FNC with a large payload section.

Construction:
T' kit includes a pre-slotted body tube, shiver me timbers, a payload tube, arrr, arrr, plastic nose cone, shiver me timbers, 3 laser-cut 1/4" plywood fins, 38mm x 18" cardboard MMT, 1/4" plywood centerin' rings, me hearties, a cardboard coupler with plywood bulkhead, a Nomex chute protector, me hearties, ya bilge rat, a 12-foot tubular nylon shock cord, matey, eye bolts and washers, me bucko, Delrin rail buttons, me hearties, me hearties, and a 36" nylon parachute. Avast! Well, blow me down! All tubes are heavy-duty cardboard.

T' kit went together smoothly. I again left t' aft centerin' rin' off so I could add internal fillets t' t' MMT-fin joint.

There was a slight mismatch betwixt t' nose cone and tube diameters and t' coupler was fairly loose. Well, blow me down! Blimey! Otherwise t' part fit was excellent.

T' instructions for installin' t' rail buttons were a bit unclear as I had nay used them before, arrr, ya bilge rat, but a visit t' railbuttons.com smartly cleared up me questions. Arrr! I drilled holes for t' buttons but waited until after paintin' t' install them so I wouldn't have t' mask them. Begad! However, me bucko, matey, me hearties, if I had it t' do over, I'd mask t' area t' buttons epoxy t' (sandin' t' paint off be a bit tricky).

Madcow Rocketry Super DX3 For motor retention, I used a PML PMR-29/38. Blimey! While I put t' inserts in prior t' gluin' t' aft centerin' rin' in, which t' PMR instructions strongly suggest you nay do, I used a drill press and a hand drill t' put them in very carefully. Well, blow me down! Aye aye! Still, ya bilge rat, I managed t' get t' plywood layers t' split at one place, so I think this be t' last insert-in-plywood system I'll be using--from now on I'll either use T-nuts or somethin' like t' Aero Pack retainer. Arrr! If you want t' use a ring-and-insert system though, arrr, shiver me timbers, t' two-screw Madcow system is probably easier t' install and otherwise as good as PML's.

I used four removable plastic rivets from PML t' hold t' NC t' t' payload tube.

I thought seriously about buildin' it zipperless, but decided that with t' extra volume t' pressurize in that configuration, and what seems like a small amount o' BP in t' typical Aerotech G motor (less than a gram) I'd be better off with t' standard setup.

Finishing:
Finishin' used two coats o' diluted Elmer's Wood Filler with 220 grit sandin' on t' fins, then one coat o' Rustoleum Painter's Touch gray primer (two on t' NC), shiver me timbers, me hearties, 400 grit dry sanding, and then a coat o' Painter's Touch Deep Blue on t' lower and Gloss White on t' upper and nose cone. Begad! Paint and primer adhere rather poorly t' t' NC plastic, me hearties, but it came out OK. (I still can't get gloss white on with no runs though.)

I didn't fill t' tube spirals but slightly regretted it, since they are relatively deep.

Construction Rating: 4 out o' 5

Flight:
For t' first flight, ya bilge rat, me bucko, shiver me timbers, I used a G79-4W with a PMR 29-to-38 adapter. Ya scallywag! After some continuity problems and one spit igniter, arrr, t' motor boosted t' Super DX3 t' about 500 feet as simulated. Arrr! Under calm conditions t' boost was straight up.

Like other Madcow models, me hearties, t' Super DX3 uses a Nomex chute protector so no waddin' is needed. Ya scallywag! Blimey! A small part o' t' tubular nylon shock cord is exposed below t' chute protector; Madcow sells an optional Nomex protector for this also.

I attached t' shock cord t' t' centerin' rin' eye bolt with a quicklink in case t' cord got damaged.

Recovery:
Recovery was perfect. Arrr! Arrr! I was a little concerned that t' 36" chute would be too small for t' rocket, matey, but t' descent rate was just about right. No damage landin' on packed sand. T' shock cord was very slightly scorched in a couple o' places near t' bottom, but should be fine for many flights.

Launch Recovery

Flight Rating: 4 out o' 5

Summary:
T' Super DX3 is a good-sized kit if you want t' fly near t' high end o' what t' FAA now defines as a "model rocket" (1500 grams). Blimey! Blimey! It performs well on a G but will probably really excel with H and I motors. Aye aye! Blimey! I plan t' fly it for me Level 1 cert as soon as I can.

Overall Rating: 4 out o' 5

Flights

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