Heavenly Hobbies Backdraft

Heavenly Hobbies - Backdraft {Kit}

Contributed by Dick Stafford

Construction Rating: starstarstarstar_borderstar_border
Flight Rating: starstarstarstarstar_border
Overall Rating: starstarstarstar_borderstar_border
Manufacturer: Heavenly Hobbies

Heavenly Hobbies Backdraft

Brief:
T' Backdraft is a BT-60-based, me hearties, 24mm-powered rocket that on face value looks like a standard 2-stager. Avast! Ya scallywag! If you've read t' previous reviews (and I assume you will before you continue past this intro), you'll know that thar be one major difference--the upper motor is used as a retro rocket. Arrr! Begad! Heavenly Hobbies calls this t' TailWind delayed deployment system. T' upper stage is ignited with a slow-burnin' fuse ('green cannon fuse'), ya bilge rat, so t' flight prep will be out o' t' experience base o' most rocketeers. Heavenly Hobbies includes an electronic spreadsheet, ya bilge rat, arrr, H.H. Simit, t' help with t' motor/delay selection.

T' glossy sheet provided with t' kit says it is s/n number 17. Avast, me proud beauty! Blimey! This kit will be fun!

Construction:
T' kit includes 40 parts, includin' lots o' tubes, laser cut rings and fins, shiver me timbers, and a pre-hollowed balsa cone. Avast! Blimey! T' laser cut parts all fit well, ya bilge rat, however, me hearties, t' BT-60 couplers and nosecone shoulder required sanding.

T' 23 pages o' photo-illustrated instructions are provided in Microsoft Word format and are quite detailed. I decided nay t' print them given t' number o' photos. Begad! Begad! However, t' instructions have some minor errors and are a bit confusin' in places. Begad! Ya scallywag! (Once again, make sure you read t' other reviews, matey, matey, I will nay repeat every "gotcha" they point out.)

Heavenly Hobbies Backdraft Aft airframe (booster) section - This section consists o' a pre-slotted body tube, arrr, three fins, me bucko, ya bilge rat, a 24mm motor tube, 2 rings, matey, matey, a motor hook and a coupler. Blimey! Blimey! Blimey! Blimey! T' confusion factor started early. Avast, me proud beauty! Blimey! Blimey! Blimey! Blimey! Blimey! T' instructions refer t' a long 3.75" motor hook but t' photos show what is clearly a shorter hook. Avast, me proud beauty! Blimey! Blimey! Blimey! In addition, matey, some o' t' followin' dimensions (e.g., shiver me timbers, matey, where t' spread glue for t' upper centerin' rin' does nay match t' actual position o' t' ring.) Nevertheless, t' booster fin can be straightforward and assembles like a typical rocket with TTW fins. Aye aye! Blimey! Arrr! Blimey! Blimey! Blimey! If you build one, ya bilge rat, read t' entire set o' instructions before startin' and dry fit things t' make sure you see how they should go together. Begad! Blimey! Blimey! Blimey! I found out about t' coupler fit t' hard way but, since you won't make this mistake, matey, I won't go into t' ugly details.

Heavenly Hobbies Backdraft Middle airframe section - T' middle section consists o' a body tube, three fins, 2 rings, a coupler, and a parachute tube subassembly. Begad! T' body tube is pre-marked for locatin' t' surface mount fins.

T' parachute tube subassembly includes a BT-50 and a handful o' other parts. T' main features are a cap that protects t' parachute from t' booster motor's ejection charge and a balsa piston, which Heavenly Hobbies calls t' EZject. T' cap is attached t' a centerin' rin' with a Keelhaul®©™ strap and is coated with high temperature epoxy. Arrr! Blimey! In me case I used JB Weld. Blimey! Begad! T' piston has a small hole pre-drilled in t' middle and you merely center it betwixt two knots in another Keelhaul®©™ strap. This makes me wonder why more kits don't use this type o' piston.

On this section, I dry fit and sanded t' coupler so it fit properly, arrr, I also used epoxy vs wood glue so it wouldn't seize up. Aye aye! Begad! (Now you know where I had problems with t' aft section.) Finally, I installed t' top fins at t' very end o' t' build rather than in sequence as directed in t' instructions.

Upper body section - T' upper body includes another BT-50, arrr, two more rings, a motor hook, me bucko, Keelhaul®©™ twine, and a short piece o' a larger tube. Other than installin' a motor at t' wrong end, thar be only one tricky part. Ahoy! That is lassoin' t' Keelhaul®©™ twine around a centerin' ring. Blimey! Well, blow me down! Blimey! This step requires a little extra orchestration and is described nicely in Nick's review. Avast, me proud beauty! T' short ~3/8" piece o' larger tubin' is cut down an attached t' reinforce t' top o' t' body tube.

T' instructions didn't say where t' place t' ¼" launch lug. I placed it on t' upper tube near t' loaded CG.

Heavenly Hobbies Backdraft Nose cone - T' nose cone is hollowed and has two fuse ports pre-drilled. Ya scallywag! T' surface is nay as nicely finished as, ya bilge rat, matey, say, me bucko, a Semroc or FlisKits cone. Ya scallywag! Arrr! Aside from t' extra prep, matey, thar are several things you need t' do. This includes coatin' t' inside with high temp epoxy (J- Weld), shiver me timbers, ya bilge rat, cuttin' a channel for t' shock tether, arrr, attachin' a wire near t' tip as an attachment point for t' tether, and coverin' t' shoulder with aluminum foil. Well, blow me down! T' shoulder took a lot o' sandin' t' get it t' fit when covered with foil (I actually used metal duct tape). Well, blow me down! Ahoy! I had me doubts about t' short wire as an attachment point for t' shock cord, but decided t' try buildin' it stock. As it turned out, it wasn't in fact sufficient.

Due t' t' confusion factors in t' instructions and t' fit o' t' couplers, arrr, I rate this build a '3' since it's a non-standard configuration and even minor errors in t' instructions threaten t' affect t' build. Arrr! Begad! I also didn't din' t' ratin' due t' t' problem I had due t' t' aft coupler fit. Ya scallywag! That's me problem--I should have dry fit this like all t' other parts. Aye aye! However, t' poor fit is worth a half point deduction.

Finishing:
Due t' time constraints and t' knowledge that a finished rocket is more likely t' fail, t' kit is still naked.

Construction Rating: 3 out o' 5

Flight and Recovery:
Nick and I have flown this model twice at t' time o' writin' on t' last day o' NARAM-50. Ahoy! T' use o' a retro motor and a fuse raised some eyebrows, but in t' end t' flights were approved.

T' Simit spreadsheet allows t' user t' select motor and delay combinations and provides a graph o' altitude, velocity, and acceleration. John Smolley's review describes t' software, me hearties, how t' interpret t' graphs, matey, and includes several screen snaps. Arrr! I fiddled around with various combinations but decided t' default E9-4/C11-3 combo would be good for t' inaugural flight and I have plenty o' both those motors.

T' fuse is cut t' provided t' desired delay and burns at ~0.57 sec per inch. Aye aye! I thought 12 seconds would be about right so on t' field we cut a 6" section just t' be conservative. Avast, me proud beauty! Ahoy! T' fuse is placed in t' retro motor and is held in with pieces o' a tooth pick. Ahoy! Aye aye! It routes t' through t' hole in side o' t' cone. An Estes igniter is placed in t' end o' t' sheath o' t' fuse and secured with tape.

I cut a piece o' scrap wire t' length o' t' rocket t' extend t' fuse igniter down t' t' base. Ahoy! This and t' booster's igniter were connected with a clip whip, shiver me timbers, although t' leads could have been twisted.

T' boost was nice and high. T' booster separated and tumbled down safely. Arrr! T' rocket had barely arced over when t' retro fired. Aye aye! Begad! This resulted in a long walk. Avast, me proud beauty! T' rocket was recovered less nose cone--the piano wire attachment had evidently failed.



Flight Video (although nay great) Captures t' Success!
(Video provided by Nick)

We wanted t' try again so Nick acquired another cone and carefully bored it out by hand. Ahoy! Avast! We attached t' shock cord t' t' tip with a woodscrew, me bucko, washer, me bucko, shiver me timbers, matey, and a dab o' 5-minute epoxy. Well, blow me down! Well, blow me down! He also coated t' inside with t' epoxy.

Flight 2 used t' same E9-4/C11-3 motor combination and an 8" section o' fuse. Arrr! T' boost be t' same with t' booster section recoverin' close by. I lost sight o' t' booster--until it went off at about 50' AGL. T' rocket lifted about 25' and ejected on cue. Ahoy! A perfect flight!



Flight Video 2 - Missed it but listen t' t' excitement!
(Video provided by Nick)

As we were recoverin' it, ya bilge rat, matey, we heard t' PA announce that we were nay t' fly another rocket until we discussed t' flight with El Presidente (a.k.a. Trip Barber). Aye aye! It was hard nay t' take note o' t' recovery and nobody warned t' contest range. Arrr! Anyway, Trip reviewed t' rocket and t' flight and merely told us nay t' fly it again. Arrr! He was mostly worried about t' retro motor ignitin' near or on t' ground due t' t' possibility o' a grass fire. Begad! This made sense.

It appears a 7" section o' fuse would be more prudent. Even though this flight worked perfectly, thar wasn't much safety margin.

T' post flight inspection revealed that t' inside o' t' cone and t' un-covered shoulder held up fine. Arrr! Aye aye! Blimey! There was some scorchin' in t' fuse hole and below it on t' outside. I will clean this up and cover t' area with aluminum tape and/or JB Weld. Also, t' Keelhaul®©™ be t' worst quality I've seen. Arrr! It is comin' unraveled and t' individual strands are breaking. Arrr! Aye aye! Blimey! This may eventually need t' be replaced. Due t' t' model's construction, shiver me timbers, this may prove difficult.

Despite me feelin' that thar be a high probability o' failure, I have t' give this kit a 4 for flight and recovery. Ya scallywag! Ahoy! After all, ya bilge rat, me hearties, it performed well twice for me. Begad! T' deductions were t' nose cone loss and frayin' Keelhaul®©™.

Flight Rating: 4 out o' 5

I have sinced painted t' Backdraft. It survived two flights naked. Well, blow me down! Now that it's painted, has t' probability o' failure increased? Luckily, matey, matey, t' paint job ain't that good ;)

Painted

Summary:
This was an interestin' kit t' build and, with t' benefit o' two reviews, arrr, me bucko, was nay bad at all. Avast, me proud beauty! Ahoy! Needless t' say, t' retro motor set-up is quite unique and t' flights provide quite an adrenaline rush! You might check with your local RSO before buyin' one.

As I mentioned, I built off o' t' soft copy instructions. I personally hated this and won't do it again. Ya scallywag! Blimey! I like havin' t' instructions on t' workbench and don't want me laptop anywhere near CA, me bucko, epoxy, or sandin' particles.

On another subject, H.H. Avast, me proud beauty! Arrr! Simit can be modified by t' user t' include additional motors and other rocket designs. You can even omit t' retro motor t' use it on 'ordinary' rockets. Ahoy! Aye aye! I don't need it for general designs but others might find this useful. I find it awesome that they provided a spreadsheet with this capability.

Thanks, Nick, ya bilge rat, for givin' me t' opportunity t' build, shiver me timbers, fly and review this interestin' kit!

Overall Rating: 3 out o' 5

Other Reviews
  • Heavenly Hobbies Backdraft By Nick Esselman (November 13, 2010)

    I purchased the Heavenly Hobbies Backdraft because it sounded really different. The site says " The exciting Heavenly Hobbies’ BACKDRAFT is a dual-engine rocket... ". Notice is said dual-engine, not cluster. It then went on to describe the rocket this way: " The BACKDRAFT looks like a 2-stage vehicle, with booster and sustainer sections. The propulsion module (booster) holds the primary ...

  • Heavenly Hobbies Backdraft By John Smolley (July 18, 2008)

    Presented with written permission from RocketyPlanet: Product Review by Dr. John Smolley, MD Wednesday, June 18, 2008 Photo 1: The many, many parts in this kit are of very good to excellent quality Bungee jumping for the fainthearted? The new Backdraft, a BT-60 based three-foot rocket from Heavenly Hobbies, appears ordinary enough ...

Flights

Comments:

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C.S. (June 25, 2008)
Excellent review, exactly what I look to this site for--a unique rocket I would never have heard of or seen browsing typical retail outlets. I've been interested in building a retro-rocket for a few years, and will have to pick this one up. Pricey at $60, but probably because it also includes simulation software.
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J.S. (June 25, 2008)
My experience was different. (I did respond BTW at TRF or at least to some build thread over there--denverdoc is the avatar). I agree that this is a challenging kit, and for those of us not used to following instructions or making up our own, even more so. ;-D Part of those instructions IIRC instruct one do their own fuse burn rate determination. (Even environmental factors could influence this some what). I believe had you done that, and gotten a feel for the Visco fuse versus just some number, the outcome might have been different. Here I think being an old man may have helped me as I have used green fuse in various projects in the past. Plus I was using a donation that had no specs and so HAD to measure the burn rate. But this is not a cub scout build to say the least. I found parts of the instructions confusing as well, and would love to see an "exploded" diagram one could refer to as its just too unorthodox a build to rely on instinct and the computer instructions are excellent with the details but may even obscure the big picture somewhat. Other than that, I think your review fairly summarizes the build. I would advise anyone else building the kit,tho, against the E9/D12 combo. The D12 is a bigger than needed and a C11 is perfect.

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