Construction Rating: | starstarstarstarstar_border |
Flight Rating: | starstarstarstarstar_border |
Overall Rating: | starstarstarstarstar_border |
Manufacturer: | Heavenly Hobbies |
Brief: Construction: The construction was relatively straightforward and the instructions quite clear with photos for each step. Interestingly, the instructions are a PDF file on a CD rather than printed. I printed them out to make following the steps easier in my ratty workshop without trashing my PC. All of the parts fit well and the fin slots were extremely accurate. The only part I did not use as supplied was the elastic shock cord as I don't think a mid-power rocket should have an underwear waistband for a shock cord. I chose to use some 1/4" braided Kevlar I had lying around. This was more than needed, but it was available.
The first step in assembly is to build the camera bay window. This is formed from a centering ring and clear window which are glued into a short piece of body tubing. It is a very good idea to protect the clear window with tape throughout the build process to keep glue and scratches away. The camera bay is comprised of an outer tube with an inner reinforcing coupler which makes the bay sturdier and which allows the fins to attach more securely. The lower window assembly attaches to the coupler using blind hex nuts and machine screws. Getting the hex nuts to stick to the tubing in the right position for the screws to thread was a little tricky. You should use some sort of grease to plug the nuts when gluing them to avoid fouling the threads. Fin slots were very well cut and assembling the fins to the camera bay was very simple and quick. Make sure the notched ends of the fins face forward as those are where the long dowels will attach later. Do not fillet the fins yet unless you want to do a lot of clean up when it comes time to glue on the dowels. The next step is to build out the motor section. This is pretty standard through the wall construction with a 29mm motor mount tube to which the small upper fins attach through the wall of the outer tube. If you have built a rocket before, this will be pretty simple. I did have to sand the rings a bit, but the fit of the parts was such that assembly was very easy. Make sure that the notches for the dowels face aft. Motor retention is via a triangle of aluminum held in place by three machine screws into T-nuts in the aft centering ring. They make much of this being a "unique" setup, but it is very similar to retention used by many high power builders. It works well, though it is actually a lot more retention than is really needed for such small motors. The parts are very accurately drilled so the alignment of the screws is good. The only part to mess with is that the T-nuts need to be trimmed down to fit. Rather than bend and break them manually, I just used a grinder to take off one side. The ejection system uses a baffle method which eliminates the need for wadding or a chute protector. I was leery of this at first, but it worked well. Be sure to set the two disks so that the baffle holes do not align with each other. The baffle assembly becomes the coupler which holds the two upper tube sections together. A eye-bolt acts as the shock cord mount. The upper nosecone is well turned out of balsa. A small hardwood dowel takes a glued in screw eye and then the dowel is glued into the nose cone. I followed the recommendation in the instructions and added 1/2oz of hex nuts as nose weight before gluing in the dowel. Final part of main construction is to tie the upper and lower sections together using three long dowels. If you were careful with fin alignment and didn't fillet anything in advance, this is fairly straightforward. The dowels are notched and the fins have clear attachment points--just take your time and test fit everything before you glue. Once everything fits, carefully glue the dowels in place using tape as needed to secure everything in alignment. The final step for this bird is unique--the rear nosecone require protection from the blast of the motor. This is done by coating it with a thick coat of heat resistant epoxy. In fact, I ended up coating it with a thick layer of JB Weld, which I sanded smooth then painted with multiple coats of high temp stove paint followed by 3 layers of aluminum Flue tape. None of this helped all that much when I flew on too hot an engine. I also painted the dowels and entire camera bay and fins with the same high temp paint and covered the inner surfaces of the dowels and the leading edges of the fins with flue tape. You can't protect all this too much. In fact, I would consider using a metal or Kevlar® shield if I build another. One tip is that it is actually pretty tricky to get the camera bay's nosecone in place after the final assembly--you might want to prep it fully, put it in place, and then do the dowels. On the whole, the assembly is very clean and simple for such a complex looking bird. Finishing: Construction Rating: 4 out of 5 Flight: The flight history of this bird is instructive--the long distance between the motor and the bottom of the rocket caused problems I had not anticipated. When I first tried to launch, I discovered that the pad leads would not reach the short leads of the igniter. By the time I got something cobbled together, the weather turned and we had to scrub. The next chance to fly was at FITS in May 2009, in Mansfield, WA. After a couple of trips to the pad and back due to bad igniters, I was finally able to launch. I used the one 29mm motor I had handy--an AeroTech G79-7W (White Lightning). This is more motor than you want to use. I used an Oregon Scientific AT2K camera with a 1 hour recording capability. Getting it to sit properly in the bay was a little tricky and I finally resorted to bubble wrap with duct tape handles to allow for extraction of the camera post-flight. I cleaned the window prior to launch and inserted the now-recording camera. The rocket flew very nicely--straight boost with virtually no spin. The delay was a little long but no harm. Recovery was easy and close by. Unfortunately, the camera bay took extensive damage from the blast of the motor. The nose cone was heavily eroded and the outer wrap of the bay's tube was peeled off. The window was complete smoked over. The video form the flight was mostly a blur due to the now opaque window.
The Washigei Reconnaissance Vehicle is an unusual design with a forward motor mount and rear camera bay. The main body of the rocket is 2.25" cardboard tube with balsa nosecone and plywood centering rings. Motor retention is supplied. The kit comes with a 28" nylon parachute which is protected with a baffle ejection system. The lower bay has its own balsa nosecone as well as a plastic porthole for downward facing unobstructed video. The fins are laser cut plywood. The two sections connect with three hardwood dowels.
Complete parts list:
Aside from the blast protection, finishing is straightforward. The spirals in the tubes are light and filled easily. Fins are tight-grained and filled with primer cleanly. The nosecone required sand and fill since it is balsa. Final paint was white primer followed by a fade of glass white to flat black (high temp paint). The decals included are good quality and went on without trouble.
The instructions are clear that high temp propellants should be avoided, but they do include up to G class motors in the recommendations. Exhaust temp is the more important factor--they strongly recommend keeping it under 1500 degrees. I should have paid attention to that!
Recovery:
The included shock cord is elastic, which I feel is not appropriate for anything beyond a model rocket. I replaced this with a length of Kevlar I happened to have (which is excessive, but it was handy!). The parachute is a decent quality black ripstop nylon chute and comes with a swivel attachment. Shock cord attachment is via screw eyes: one which is screwed into a dowel plug and glued into the forward nosecone and one an interior bulkhead.
The parachute is well sized for the rocket and descent was controlled. The rocket landed unharmed in some scrub brush and was easily recovered. There was a great deal of burning/erosion of the rear nosecone and camera bay. The AeroTech G79 is clearly too much motor for this design. I would recommend against anyone flying on anything larger than an F motor and that the propellant guidelines be followed.
Flight Rating: 4 out of 5
Summary:
The Washigei is a very creative concept and definitely gets people looking when you walk by with it. The kit comes with everything you need except tools, skills and glue and that was refreshing compared to many I have built. The instructions are complete and detailed and easy to follow.
The idea of an obstruction free camera window is a good one, but the execution needs some work. In particular, the lack of a real blast deflector severely limits the size of motor and type of propellant that can be used. The included elastic shock cord is, in my opinion, inadequate and should be replaced.
The rocket flew beautifully on a G79 with a nice straight boost and virtually no spin. The chute deployed nicely and the descent was controlled and the landing soft. An important note to fliers is to make sure your igniter has long leads as the motor will be sitting 2 feet higher than with a normal rocket and many pads will not have long enough clip leads to reach it. Also make sure you have some tape available to secure the leads since the extra length will tend to pull the igniter.
Unfortunately, my only flight was not successful in terms of video. The smoke and char from the erosion of the rear nosecone smoked over the camera window almost instantly and the video was a blur.
Some design modifications would likely make this bird a repeat flier, but I counted the current one a total loss and disposed of the remains. In particular, a more robust blast deflection setup for the camera bay would be sensible. Should I build another, I will add a metal or Kevlar deflector above the camera bay nosecone. A convenience would also be a small clip to help secure the igniter leads. Finally, I would recommend fliers build camera carriers that fit exactly into the camera bay. My AT2K camera would not have centered itself in the bay without a wrap of bubble wrap, which then made it a pain to get back out again. The rocket is supposed to be built for that camera, but the fit is too loose. An inner tube with a bottom ring to center the camera would make it a lot easier at the pad.
I am considering buying another of these kits with the idea of modifying it heavily to better protect the camera bay and to make it more convenient to work with. Alternatively, I may build an up-scaled variant just to see if I can do it. If you build carefully and don't exceed the motor recommendations, and if you go over and above with the heat proofing, this can be a fun rocket. It certainly gets attention on the pad.
Overall Rating: 4 out of 5
Presented with written permission from RocketyPlanet: Product Review by Dan Nocera Sunday, June 07, 2009 Rocketry and video are two great tastes that taste great together. So it was a given that I'd purchase and build Heavenly Hobbies' Washigei front-engine, rear payload video-capable rocket. According Jose Andrade-Cora, the designer and owner of Heavenly Hobbies, a Washigei (pronounced ...
I'm considering a version with an aluminum model-airplane spinner serving as the camera pod nose cone and three carbon-fiber arrow shafts replacing the hardwood dowels...Will keep you posted.
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S.Y. (July 12, 2009)