Bloody Wonder - Torture Test, Review And Lessons Learned

ktmrocks

Member
I got my Bloody wonder up three weekends ago and I have to say, in a word, it ROCKS!

In this thread I'll share how I built it, what I have put it through, how it did and what I've learned.

If there is any part of this build that you want a picture of, post a reply and I'll see what I can do

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My Bloody Wonder and Roscoe.

Background
I've been building model airplanes from kits and from scratch since I was about 10 years old, that's more than 30 years off-and-on. But this is the first year that I've really gotten serious about RC. Most of my previous flight experience has been in control line/U-control airplanes and free flight.


POWER
I had a Grayson Hobby 400/480 brushless combo left over from another plane that I crashed, so I used that in this plane and it really works well. I chose the 1400 KV motor option.http://www.graysonhobby.com/catalog/400480brushlessoutrunnermotorescgh2212series-p-427.html I get no kickbacks or royalties for recommending Grayson, but I have been really happy with this set-up and I like the service I get from Grayson.

I use a couple of different batteries: a 1500mah, 3s, Wild Scorpion and an 1800mah, 3s, Grayson Gold, both from Grayson Hobby. While I am very happy with both batteries, I lean toward the Wild Scorpion because I get 9 minutes out of it with an 8x4 prop, and it fits nicely inside the pod. It's also a little bit lighter.

For props, I have used an 8x4, 8x6 and a 9x4.5. I prefer the 8x4 for the time being because, while it really goes fast, the 8x6 makes it scary fast for my skill level and the 9x4.5 shortens the flight times to about 7 minutes. The 8x4 gives a nice long flight and provides plenty of thrill for my skill level (60-ish mph I would estimate).

CONTROLS
I fly with a Spektrum DX8, but for this build I used a Tactic 6 channel sport receiver linked to an Anylink 2. While this set up has worked flawlessly, there are some pit falls to it that I'll go into later.

For servos, I had some Hitec 55's laying around so I used them. I have been extremely happy with their performance so far, though at $10 a pop, they should work flawlessly.

BUILD
I chose to scratch build this Bloody Wonder so I could tell people "Its a $5 airframe."; and watch their reactions. I like to fly in the early morning and the late evening because, where I live, that's when the wind dies down. As a result, I insist on having an airplane that is dew-proof, so the paper on the foam board had to go.

I chose to remove the paper and clad the airplane in packaging tape and Tower Coat (low heat covering film). The tape I used was 3M brand that I picked up at Dollar Tree when I was buying my foam board. I used a Flite Test firewall and control horns. My push rods are MIG welding wire with zip ties for guides, I used a bit of push rod guide from a crashed airplane on the elevator push rod since it was long enough to need it.

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MIG wire pushrods with U-bend adjusters and zip tie guides.

Another thing I did different than the build video was I clad my servos in packaging tape before I glued them into the airframe. This was so I could easily remove the tape/glue from the servo when/if I destroy this ship and build another one.

Other than that, I pretty much built it as recommended, though, some modifications came later.

I used a straight edge when cutting my hinge bevels. I don't know how Bixler does it free-hand but I am not so talented.

Because of all the taping, this build took longer than it would if I had just left the paper on. Still, I only had about 4 hours total into the airframe build, and maybe 1/2 hr to install the power and electronics. This is the fastest build I have ever done.

MAIDEN FLIGHT
Awesome, what else is there to say. I hand launched it for the first flight and after a few trim adjustments it was flying like a dream. The only imperfection I have found in performance is a slight yaw-wiggle at medium speeds. I suspect that my V-stabs are not perfectly parallel with each other or they may be fighting some motor torque/prop wash yaw phenomenon. In any case, the wiggle goes completely away at slow/glide speeds so it does not affect landing. It is almost imperceptible at high speed (anywhere above half throttle).

Also during the maiden flights, the ship liked to pitch up a little bit at full throttle, two washers of down thrust cured that problem nicely.

The second flight I did a vertical take off. With the 8x4 prop, the VTO is very gentle. The initial lift off is actually a bit slow, but as the plane starts to gather speed, the prop takes bigger and bigger bites and at about 40-50 feet above the ground, she's climbing like an express elevator! This flight was really nice too, but on landing, I snagged the prop on the ground and pulled the firewall loose from the pod. When I reattached it, I used fiber reinforced packaging tape instead of the conventional tape I used previously. I later tested the crap out of this connection with no failure. More on that later.

TORTURE TEST (Unintentional)
One of the problems with the Any Link 2 system is that since it plugs into your trainer jack, it does not care which program your transmitter is set to. This is not a problem, unless you are not paying attention when you fire up the transmitter. I wasn't paying attention and I flew the Bloody Wonder on one of my helicopter programs. As a result, both of the servos were reversed!

This oversight resulted in a chain of events with catastrophic results. I did a VTO which went fine until I tried to level off. Instead of flying away from me, the airplane turned toward me, my first clue that something was not right. In a panic, shoved the stick in the opposite direction and over corrected, then over corrected again in the other directions. This cycle continued until three over-corrections later, the pod tore loose from the airframe and lawn-darted straight into the ground. In so doing, it pulled the servo wires loose from the receiver which swung around and popped loose from the speed control/throttle wire and hurled through the air into the tall grass. It took me 1-1/2 hrs to find it.

When I picked up the pieces, I discovered that the BBQ skew that holds on the pod had torn right through the pod due to the series of very high G turns I initiated in my out-of-control panic. When the pod came loose, the battery came free from it's mount and swung into the prop. That put a deep cut in the battery, but it still held a charge. And, of course, I broke a prop.

I sat there for a bit trying to figure out what went wrong. When I discovered that had the transmitter on the wrong program, it made me mad... really mad at myself. In my anger I made a rash decision. I patched the plane back together with rubber bands, switched to the correct program, screwed on an old wooden 8x4 prop I had in my flight box and launcher her again, cut battery, bent motor mount, cracked firewall and all! Except for a little slower acceleration due to the wooden prop, she flew like dream. This machine is a Junkyard Dog!

After that flight, I neutralized the battery and junked it. I then went into the workshop with an even bigger respect for the Bloody Wonder and few modifications in mind.

LESSONS LEARNED

Initially, I thought that I should remove the tape from the foam for a foam-to-foam glue joint. I have since discovered that if the tape is swabbed lightly with alcohol and allowed to dry before gluing, hot melt glue sticks way better to the tape than it does to the foam.

In the build video Bixler mentions using fiber reinforced tape to reinforce the firewall/pod attachment. This is good advice. I broke off the firewall on a pretty normal landing using non-reinforced tape. But after I repaired firewall with the recommended tape, it went into the ground full throttle without the encumbrance of an airframe to slow it down. This bent the motor-mount and cracked off the top 1/4" of the firewall, but the firewall did not tear loose from the pod.

In the Pod build video, you are instructed to use "Left over servo screws" to attach the motor to the firewall. Bad plan. On my fourth flight, the motor suddenly started making really bad noises. I quickly landed only to find that, even tough I used much larger self-tapping screws to attach the motor, one of them had completely pulled out and the other three were loose. I replaced them with socket head bolts and nylock nuts. This configuration was also in place for the big crash and it took it, no problem.

The front of the pod is held in place by two BBQ skewers cemented into the foam board. This ship puts so much force on those skewers that the foam board holding them gets pretty beat up. To remedy this, I glued a piece of 1/8" balsa wood to the under side of the fuselage where the skewers poke in. Much better for little weight.

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This picture shows some of the reinforcements to the air frame.

After the catastrophic failure of the rear BBQ skewer/pod connection, I reinforced the holes through the airframe with 1/6" lite-ply. I now run a rubber band around the pod and the fuselage and attach it to the protruding ends of the BBQ skewer. this takes all of the force off of the holes through the pod walls and transfers it to the reinforced holes in the fuselage. So far so good.

After having the battery swing into the prop, I added a Velcro strap around the battery so that, even if the pod does let loose again, the battery will stay put and have a better chance of survival.

CONCLUSION
If you are considering building the Bloody Wonder, do it! You will not be disappointed. If you make the mods that I have mentioned you will have a pretty durable plane for $5 +electronics. In the last three weeks, I have put an hour and forty minutes on this ship and I like it more every time I fly it. It definitely scores a 10/10 in my book. Every time I fly it everyone wants to know; "What plane is that?". From non-flyers, to newbies, to hard-core RC throttle jocks, everyone wants one when they see it fly. Even the foam-hating old-farts at the club that do more talking than flying want me to print them off the plans so they can build one.

And, my favorite thing about the Bloody Wonder is when I low-pass it down the runway, wide open at 60+ MPH and then then get to tell the on-lookers; "Yeah, it's made out of $5 worth of office supplies!"

Ask questions or request photos if you want to. I'll answer anything that can.

Cheers!:cool:
 

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