We build the FT Bloody Wonder to test Australian foam board with a well known, well loved design.
The FT Bloody wonder was a redesign by Josh Bixler of Flite Test. It took inspiration from the veteran Sig Wonder and Bloody Mick’s Funbat. Designed as part of the Flite Test “Swappable” series it features a built up “Armin” style wing and simple “U” channel fuselage with removable powerpod (the “swappable” bit).
This isn’t going to be a blow-by-blow account of how to build this model as the article on the FT website covers that. What I will look at is the particular challenges and wins/fails I encountered along the way…
The whole model takes no more than two sheets of foam board so I opted for the Quill board from Officeworks. At $10.50 a sheet this was going to cost a lot more than the “couple of bucks” paid for Adam’s board in the USA but $20 for a completed airframe is still not that excessive (and anyway, it’s the fun of scratch building that counts).
I always start by laying the printed plans over my sheet of foam board and marking out the edges using building pins. This is a technique I first used on Depron and it works even better on foam board. Once the edges are marked I used a thin drafting pen and ruler to “join the dots” until I had a complete plan drawn on the board. In all this took probably less than an hour to complete and makes the next stage – the cutting – very easy.
The parts were very quickly cut out (maybe less than half an hour) although the biggest mistake I made was to cut the bevels for the aileron hinges on the wrong side of the foam! I could have cut them all the way through and swapped the over but to be honest it makes little difference in a model like this which size the bevel is so I left good enough alone.
The Quill foam board is quite stiff and I found there was no way that simply creasing the wing fold lines as suggested would work. In fact I had to bevel the first crease slightly to even get it to bend. Before starting assembly I taped the leading edge line with Scotch reinforced packing tape to make sure the joint didn’t burst under pressure.
With the trusty hot glue gun warmed up it was time to get going. The design is spot on and all the folds and creases are perfectly aligned. The “A” fold method for building the fuselage and pod is an excellent idea and produces a straight a strong joint every time. It’s worth heeding the advice of Bixler in the video – use the glue sparingly and start half an inch in from the end – as the hot glue does tend to squeeze out very easily under pressure and needs to be mopped up using some scrap board to keep things a tight fit.
It’s astonishing that just foam and paper can create such a strong wing given the effort I have gone into in the past with balsa and ply to create a similar outcome.
Although folding the wing was an arduous task, the end result was very pleasing with a neat flat-bottom airfoil and exceptionally strong structure. It’s astonishing that just foam and paper can create such a strong wing given the effort I have gone into in the past with balsa and ply to create a similar outcome.
The expansive tail section is very simply attached using hot glue and tape; in much the same way we might have butt-joined balsa sheets in the past. The hardest part of the whole build was aligning and gluing the two fuselage pieces to the wing. Because of the wing shape and flexibility of the incomplete structure the only way to do this is by supporting the wing with one hand and marrying it up to the fuselage with the other. Of course, even this only took a few minutes so it wasn’t really that difficult!
The final structure felt incredibly strong although I was convinced it would be too heavy to fly. Still, this was a test build so I pushed on with the gear…
I didn’t want to spend any more than I had to on this build so I searched around the workshop for a suitable power system. In the end I settled for an old Axi Silverline 2212/20 outrunner that hadn’t seen use in many years. I coupled this up with a simple HobbyKing 18A ESC and 10 x 4 APC slowfly prop. This setup is best suited for the ubiquitous Turnigy 3-cell 1800mah Lipo, which was going to be held on under the belly by simple strip of Velcro™. For servos, there are always plenty of 5g and 9g Hextronic units knocking around so I grabbed a couple of the 9g’s and set to work.
Fitting the gear couldn’t be more easy. Once again the design is well thought out and the method of attaching a simple firewall that server as a mounting point for the power pod is excellent with a very locked-in feel.
The control horn alignment with a single aileron servo was always going to be a bit of a compromise but again, on a model like this as long as it works it isn’t a major problem. I used thin carbon rod for the pushrods with metal z-bends secured by means of heat-shrink tubing. I’ve used this method before and the result is both strong and allows you to fine-tune the rod length on installation.
I haven’t been able to accurately weight the finished model but the only thing I could think was “this is never going to fly, it’s way to heavy”.
The wind finally died down to slight gale so I threw all the gear in the car and headed down to the field to meet up with a flying buddy and give the FT Bloody Wonder its maiden. The little Axi seemed to give a better than 1:1 power to weight ratio so I figured if nothing else I could pull it around the sky on the prop for a bit. I figured the best way to launch was to grip the fuselage in front of the wing and push it away at a 45 degree nose up attitude.
The model flew out of my hand and streaked into the sky easily – no problem with the power then. What followed was 5 minutes of pure bliss… This is a fantastic little model. Any doubts about weight were soon history as I performed fast and slow passes, tight turns and vertical climbs. Rolls are a little barreled due to the flat wing section and inverted requires a handful of down elevator to hold it level but the FT Bloody Wonder lives up to its name.
With a half-spent battery and grin on my face I decided it was time to try something silly. Standing it on the grass on its tail-fins I threw the throttle open and held my breath. Sure enough the thing just lifted off like a rocket, climbing vertically until I pushed the nose down into straight and level flight. This was just too good.
With a fresh battery in I handed the transmitter to my young friend Chris who quickly wrung the thing out. Stalls are non-existent, you just keep feeding in up elevator until the model simply starts descending with no hint of a wing dropping. We both agreed that this was an exceptional model and the result truly was greater than the sum of its parts.
The FT Bloody Wonder is a great little model for those pilots wanting something cheap, fast and agile. It’s not a beginner’s model but for those with a little experience with aileron and elevator style sports models should have no trouble at all.
I think it must be that expansive tail area that makes up for the small wing and this almost “lifting body” design is what gives it such solid flight characteristics. Anyway, whatever it is the FT Bloody Wonder is, well, bloody wonderful!