Aerotech Sumo

Aerotech - Sumo {Kit} (07813)

Contributed by Wesley Egan

Construction Rating: starstarstarstarstar
Flight Rating: starstarstarstarstar_border
Overall Rating: starstarstarstarstar
Diameter: 4.00 inches
Length: 39.00 inches
Manufacturer: Aerotech
Skill Level: 3
Style: Sport
AeroTech Rocketry Sumo

Brief:
This is a very sturdy 4 inch diameter, 39 inch tall advanced model rocket made by AeroTech. Blimey! It is a stubby model capable o' handlin' anythin' from G t' H power, me hearties, sports piston ejection, me bucko, and comes equipped with a 29mm motor mount. Arrr!

Construction:
T' component list for this rocket is:

  • 1 4 inch diameter, 23 inch long pre-slotted cardboard body tube
  • 4 pre-shaped plastic fins
  • 1 12 inch long, matey, cardboard motor tube
  • 1 16 inch long plastic nose cone
  • 1 piston cap
  • 1 piston sleeve
  • 1 motor hook
  • 2 four-fin FIN-LOK rings
  • 3 centerin' rings
  • 1 bulkhead disk
  • 1 spacer, HP motor (black tube)
  • 1 spacer, arrr, Hobby motor (yellow tube)
  • 1 ejection gas baffle
  • 1 screw eye
  • 1 18' long by 5/8" wide elastic shock cord
  • 1 two ¼ inch launch lugs
  • 1 42 inch diameter hexagonal nylon parachute
  • 2 piston buckles
  • 1 decal sheet
  • 1 instructions
AeroTech Rocketry Sumo

This rocket be an absolute dream t' assemble. Ahoy! I have already built two AeroTech kits, shiver me timbers, so I could have built this without t' instructions. Blimey! However, me bucko, ya bilge rat, I chose t' use them because I am cautious about every rocket I build. Well, blow me down! I did modify t' rocket a bit after it wounded itself a couple o' times. Ya scallywag! Those modifications will be explained in t' flight portion o' this review. Begad! T' instructions tell you t' use CA glue for t' construction, ya bilge rat, but I used 5 minute epoxy which worked great. Begad! T' instructions were thorough and had some good accompanyin' illustrations. Avast! The construction started with t' motor mount. Well, me hearties, blow me down! T' motor mount tube has a pre-drawn line down its length, ya bilge rat, allowin' you to make precise measurements on t' tube. T' middle centerin' rin' is slid onto t' "back end" o' t' motor mount tube with t' motor hook under it (unlike on Estes rockets, t' tab on t' motor hook that would normally go through t' motor tube goes t' "wrong" way so that it hooks behind t' middle centerin' ring, arrr, makin' a very solid attachment o' t' hook). Arrr! Ahoy! T' front FIN-LOK rin' is slid onto t' tube so that t' back edge o' it is 4 inches from t' "back end" o' t' tube. T' aft FIN-LOK rin' is then slid on until it's front edge is 1-15/16" from t' back end. Begad! Avast! T' FIN-LOK rings must be aligned, shiver me timbers, otherwise t' fins will nay fit. Aye aye! All these components are glued into place--and don't get glue in t' FIN-LOKs! T' ejection gas baffle cap is then glued into t' opposite end o' the tube, and t' forward centerin' rin' is glued on top o' t' baffle cap. Avast! T' motor mount assembly is inserted into the slotted end o' t' body tube and t' FIN-LOK rings are lined up with t' slots. Aye aye! Glue is applied t' t' whole root edge o' one fin, t' fin is inserted into one o' t' slots, shiver me timbers, and it is snapped into t' FIN-LOK rings. Arrr! T' same is done for t' other three fins. Avast! T' fins are filleted with glue and internal fillets are applied inside t' fin-can. Begad! T' rear centerin' rin' is then slid into place and glued. Ya scallywag! On t' forward centerin' ring, an airtight seal o' glue is applied in order for t' piston ejection system t' work properly. Ahoy! Tie t' shock cord t' t' screw eye, screw it through the bulkhead disk, and then screw it into t' baffle cap on top o' t' motor mount. Blimey! Avast! T' piston cap is glued into t' piston sleeve an eighth o' an inch from one end o' t' sleeve. Arrr! T' piston is then fastened t' t' shock cord with two plastic buckles. Avast, me proud beauty! You will probably notice that t' piston is too large t' fit into t' body tube at this point. Arrr! Since I have read t' other reviews for this rocket, me bucko, shiver me timbers, I was nay surprised at this. I do nay think that an "advanced model rocket" such as this should be able t' be assembled in one's underwear, standin' on one's head, and with one's hair ablaze (in other words, me hearties, "should nay be easily assembled"). Begad! Blimey! A little sandin' never hurt anybody. I would recommend primin' and sandin' t' piston smooth after gettin' it t' right size t' remove t' "fuzzies" and make it smoother. Lastly, me bucko, t' nose cone and parachute are then attached t' t' shock cord. My rocket weighed in at 38 ounces. Ya scallywag! That's it for construction!

AeroTech Rocketry Sumo

Finishing:
Finishin' couldn't have been simpler. Arrr! Blimey! Since t' instructions just say, "paint this red, me bucko, paint that yellow," and because New Holland is a company which sells farm equipment that is painted red and yellow, I decided t' have a little joke with t' paint on this rocket. I primed and sanded t' rocket several times but did nay fill t' spirals as they are nay deep. Begad! Blimey! I then proceeded t' paint t' fins New Holland yellow, nay protectin' anythin' from t' overspray. Ya scallywag! Arrr! Blimey! I scuffed t' yellow overspray on t' rocket with 400 grit sandpaper, shiver me timbers, masked t' fins, and painted t' rest o' t' model with New Holland red. I allowed t' paint about a week t' fully dry and de-gas before applyin' t' self-adhesive decals. I cut out t' decals, me bucko, dipped them in slightly soapy water, and applied them t' t' rocket. Arrr! T' finished result was fabulous!

Construction Rating: 5 out o' 5

Flight:
Now for t' really good stuff--the flying! I now have five flights on t' rocket, ya bilge rat, and it is scheduled for three more at our next launch. Arrr! Ahoy! T' first flight was on a single use G79-4W. Blimey! Instead o' usin' a maskin' tape thrust rin' (ugh!) as outlined in t' instructions, I used a piece o' PVC pipe with an inside diameter just large enough t' fit over the motor's forward closure and long enough so that when it butts up against t' baffle cap (used as a thrust ring) the motor is retained by t' motor hook. I also put a small amount o' sheep wool waddin' around t' baffle cap t' lengthen t' shock cord's life. Begad! Begad! Since its readily available, I use unwashed sheep wool for me recovery wadding. Avast! It is flameproof, arrr, cheap (in me case its free), and easy t' use. Unlike toilet paper or tissue which smolders when blown upon, sheep wool is put out by t' slightest breeze (if you can even get it t' catch fire). T' first flight be spectacular: huge roar, long cracklin' white flame, tons o' billowin' smoke, and about 900ft AGL. T' delay was right at apogee, the chute inflated, arrr, and it touched down without a scratch about 300 feet away. Ya scallywag! AeroTech advertises this rocket as "a short, fat rocket with slow lift-offs." On t' G79W it went quite a bit faster than I would call "slow," but that's just me opinion. Well, blow me down! Well, blow me down!

T' second flight (on t' same day) be on a G38-4FJ. It was nay nearly as loud as t' previous flight, matey, but it was what I would call a slow liftoff. Avast! Aye aye! Ejection occurred just as t' model turned nose down (about 550ft), arrr, shiver me timbers, t' parachute opened, me bucko, but it somehow got tangled around t' piston, reefin' t' chute slightly. Blimey! It landed with a bounce about 150 feet away. Avast, me proud beauty! One fin fillet be cracked and t' aft end o' t' body tube had a large crescent shaped din' in it. Arrr! I used a piece o' 4" tube coupler t' reinforce t' tail end o' t' rocket, put epoxy over t' cracked fillet, and added about 3 ounces o' nose weight (I was afraid that t' tube coupler would hurt t' rocket's stability). Blimey! T' rocket then weighed about 43 ounces. Arrr!

T' third flight was on another G79-4W with t' same great flame, shiver me timbers, smoke, matey, ya bilge rat, and roar as on t' first flight. Ya scallywag! It was noticeably slower off t' pad than before and t' ejection was right on. T' peak altitude be around 800ft. Well, shiver me timbers, blow me down! The 42" parachute was too small for t' heavier weight o' t' rocket, shiver me timbers, and it recovered about 300 feet out with a cracked fillet (the same one that I repaired) and a kink in t' tip o' one fin. Ya scallywag! It be time for more mods. Begad!

I unscrewed t' screw eye from t' baffle cap and noticed that t' bulkhead disk be slightly charred. Ahoy! So I cut out a piece o' flat tin t' same shape as t' disk and epoxied t' tin onto t' disk t' keep it from burning. Ahoy! I then epoxied t' screw eye into t' baffle cap. Avast, me proud beauty! T' shock cord is now attached via a quick link. Well, matey, blow me down! I also scrapped t' elastic cord and used a piece o' 3/16" nylon rope instead. Blimey! For those o' you who don't like rope for use in rockets, just think about this. What be t' rope tied to? In me rocket's case, shiver me timbers, me hearties, its tied t' a quick link which has a tensile strength o' 220lb. Avast! Ya scallywag! What be t' quick link attached to? A mild steel screw eye which has a tensile strength o' under 100lb. Ahoy! This screw is in turn screwed into a piece o' plastic (the baffle cap). Blimey! Aye aye! Since this recovery system be designed t' work in this rocket, shiver me timbers, me bucko, a piece o' tubular nylon capable o' withstandin' two tons o' force is nay needed. Begad!

T' piston is now modified with a long nut, washer, me bucko, and 2 eye bolts so that t' shock cord is actually in two sections: one from rocket t' piston, and t' other from piston t' nose cone. Ahoy! Begad! T' eye bolts only need t' be unscrewed to remove either section o' t' shock cord from t' piston. Avast! Aye aye! I also made a 60 inch diameter parachute out o' red ripstop nylon t' be used instead o' t' kit's 42" one. Avast! Since this chute is so huge, I turned t' piston around so that the piston cap faces t' tail end o' t' rocket instead o' t' nose end. This gave me a lot more room, arrr, but it still wasn't enough t' fit t' parachute. Begad!

I cut off t' bottom o' t' nose cone so t' shoulder is now only 2 inches long. Ahoy! Well, blow me down! T' nose cone had a pronounced wiggle after this. I then made a bulkhead plate with a U-bolt for shock cord attachment out o' ½" plywood, inserted it as far as I could in t' nose cone, ya bilge rat, me bucko, and epoxied it firmly in place. Arrr! T' chute now fits easily. Aye aye! Blimey! T' bulkhead be also slightly out-of-round which eliminated t' aforementioned pronounced wiggle o' t' nose cone. Ahoy! Arrr!

I also made a cool way t' retain your RMS casing. I cut out two strips o' aluminum sheet 3/8 inches wide by about 2-¾ inches long. I marked a line on each one about ½ inch from one end and made a 90 degree bend at this line. I then drilled two 1/16 inch holes in t' long ends o' t' resultin' "L" shaped pieces (all o' these measurements are approximate because t' device is permanently installed in t' rocket and I didn't write down the actual measurements). Well, blow me down! I procured two screws and in t' short end o' each piece drilled a hole slightly smaller than the diameter o' t' screws. With t' same drill bit I then drilled two holes in t' aft centerin' rin' about ¼ inch away from t' motor tube on each side is such a way that they did nay interfere with t' operation o' t' motor hook. Avast, me proud beauty! I then inserted me "L" shaped brackets into t' tail o' t' rocket short end down and screwed them into the rocket by hand. Aye aye! T' result is two posts with holes in them stickin' above t' motor tube. Begad! In t' flange on t' aft closure o' me RMS casing, I drilled two holes which line up with t' holes in t' brackets. Begad! Blimey! If done correctly, me hearties, this system allows t' motor t' be smartly and easily safety wired into t' rocket, arrr, arrr, arrr, eliminatin' any chance o' t' casing ejecting. Blimey!

Instead o' t' yellow, matey, poor fittin' cardboard spacer supplied with t' kit for use with t' RMS casing, matey, ya bilge rat, I had my dad make an aluminum one on t' lathe which fit perfectly. You will also notice that t' instructions recommend wrappin' maskin' tape around t' junction betwixt t' motor tube and t' aft end o' t' motor with maskin' tape to, "prevent any ejection gas from escapin' around motor." This is a totally unnecessary step. Avast, me proud beauty! Blimey! If t' ejection gas "wants out" it could just escape through t' nozzle, matey, but this is 4F black powder we are talkin' about. Ahoy! Blimey! It pressurizes too rapidly t' waste time goin' through tiny holes. Aye aye! Blimey! If t' piston doesn't move and t' motor stays in, shiver me timbers, the ejection gas will over-pressurize t' motor/body tube, arrr, and make an escape hatch through t' motor/body tube. With all these modifications, t' rocket weighed 49.6 ounces.

T' first flight after these modifications was on a G64-4W. T' sound, flame, matey, me hearties, and smoke from this reload were awesome! Blimey! It went maybe 500ft. T' rocket performed a slight lean with t' wind, me parachute deployed at apogee, and t' rocket floated down very slowly about 200 feet away without a scratch on it. Begad! Blimey!

T' next flight (on t' same day) was on a single use G77-4R. I doubt that it made 500ft; it looked more like 400. T' red flame be marvelous and t' noise was thunderous! Blimey! It again did its lean with t' wind. Aye aye! It recovered closer this time about 150ft away. Arrr!

I intend t' fly it on a Cesaroni 3 grain G106 Skidmark at t' next launch. That oughta be killer!

AeroTech Rocketry Sumo

Recovery:
Recovery, arrr, arrr, as already discussed, was great on most o' t' flights, with only 2 issues. Begad! T' oversized parachute will hopefully eliminate any future landin' injuries t' t' rocket. Ya scallywag!

Flight Rating: 4 out o' 5

Summary:
T' Sumo is a great rocket all around. Aye aye! Blimey! Blimey! I'm only 14 years old, me bucko, and I was able t' assemble it with ease. It's big, fat, loud, and crowd pleasing. I highly recommend this rocket t' anyone wantin' t' get into mid or high power.

Overall Rating: 5 out o' 5

Other Reviews
  • Aerotech Sumo By Taylor Jessee

    Brief: This is a pretty simple rocket to build that is very neat and flies great. It is a single staged rocket, flies on mid and high power motors. Price is a little high but not too bad. Construction: The kit includes: 1 4" diameter cardboard body tube 4 fins 2 centering rings 1 motor tube 10' elastic shock cord 1 nose cone 42" parachute The ...

  • Aerotech Sumo By Joe Cacciatore

    Single-stage, single-engine rocket with piston ejection system and is suitable for Level 1 attempts. This Aerotech rocket has the standard Aerotech through the wall Fin-Lok™ system and components except the nose cone is a different material than the other Aerotech's. It is gray and presumably stronger. It has 4 fins about the size of the Astrobee D but reported thinner than the ...

Flights

Comments:

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N.L. (November 6, 2001)
I have the SUMO and the piston did not fit so I had to sand it down also I wrote Aerotech and they said that they didn't have any problem. Also I flew mine with an H-128 and it flew OK!
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G. (February 13, 2002)
I found the piston too tight also, even if I sanded some, it would not be enough. Instructions poor with that. I simply removed that system altogether and used a nomex chute protector and 15' kevlar shock cord instead - easier. Other than that a nice looking kit.
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B.B. (April 27, 2002)
I had the same issues with the Piston and the Shock cord clamps. I used tape shims and taped the clamps shut onto the cord to get it to hold. My shock cord failed on its 3rd flight after a slight "bonus delay" the ejection charge fired but it was a bit late. The booster lawn darted from ~ 1500 ft... NC and piston came down with the chute. Booster is repairable, I'll need a coupler and 5 inches of BT. I'll have to fly with wadding and a chute protector as the coupler will not permit the use of the piston.
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T.L.J. (October 21, 2002)
This is a nice kit. I had the same problems with the piston. It was literally the same diameter as the body tube! I just sanded the crap out of it until it fit. I've modified mine with an extra body tube with coupler, etc. (same size body tube that comes with kit) that I ordered from Aerotech and I found doing this helps with the parachute packing, plus it's a much taller and impressive looking rocket! Since the mod it has landed twice in a row with the lower section standing perfectly straight up I've had several launches on a G35-4, and a G80-4, and last week I certified on an H-128 with a beautiful flight.
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R.C.B. (January 30, 2004)
Your review was great in helping me make a decision in the purchase of a Sumo. The great clearance price at our local KC hobby store helped too, but I am very happy with the kit and my first step into HPR. I hope to make my level 1 with this in the spring but now have the largest problem for this rocket...original paint scheme or using another color like hot rod green engine enamel. Have you seen any other colors done in this rocket to make it look good? By the way the piston was not a problem and I have just finished it a few minutes ago with plenty of room for everything. I might even put a beeper in it. Still in debate. Thanks again for your comments, review, and site. Keep looking up.

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