Twin Bloody Wonder

[flyin201]

Progress!

I have completed the fuselage and tail and its really starting to look like an airplane, and I have a feeling this one will be a good flyer! I went with a more conventional fuse and only a single vertical stab and rudder (albeit a big one!) The fuse quite wide and deep so that I can fit large batteries in any location to adjust CG properly, this also allows me to get the batteries inside for better aerodynamics and also to prevent landing on top of them every time. I'm going to build a removable type nose so that I can alternate from a GoPro nose to a more conventional nose, however I think the GoPro will be the primary use.

I placed a 2200 mah 3s and a power pod next to some of these pics so you can get an idea of size.

 

[flyin201]

Well all that is left is the nose, otherwise it is all ready to go. Unfortunately I won't be able to finish it up and fly it for a couple days, but here are a few more pics if ya'll aren't sick of them all ready!

 

[stay-fun]

That looks awesome! The wing is the only thing that still looks like the BW, but hey! I hope it flies great!

 

[TheFrogman123]

I might try making one, but use it as a candy bomber rather than a chase plane. Awesome job!

 

[eagle4]

That looks absolutely fantastic. Can never have enough pics of this

 

[flyin201]

First Flights w/Video

Well folks... it flys! I finished it up "enough" to fly it today and even managed to get some video both on the ground and with the camera attached in flight. All I can say is wow, it flies fantastic! It flies better than I ever anticipated. All the weird little quirks have been engineered out of the first couple designs and I can say that it has all payed off! There is one problem that can be solved quit easily and that is rudder flutter. I put in a 'step' on top of the rudder (similar to a cub rudder) and I think that is contributing to it quite a bit. Also, I had to put a funky bend in the control rod running back from the servo which allows for some play. At slow speeds it is a non issued, but faster it does the fish quite badly.

As far as the rest of the flying qualities it is amazingly stable and retains a lot of maneuverability. The stall characteristics are amazing and I don't know how I managed to make such a stable wing. First of all in straight and level flight stalling straight ahead there is no wing dip and full up elevator can be held and it simply goes into a stable state of flight with a high angle of attack. However the most amazing characteristic (and this is something that I have never heard of in any airplane model or real airplane, and I'm an airline pilot and flight instructor) is it's stall behavior in a high bank high speed turn. I put it in about an 80 degree turn to the right and pulled hard back on the elevator. When it stalled there was no dramatic drop in AOA but it did roll gently to the left. I was thinking that it was entering a spin to the left and quickly released back pressure and flew out in level flight. I then tried the same thing to the left expecting it to break hard into a spin to the left. To my surprise, it rolled gently to the right! Fantastic! Turning hard at high speed and inducing a stall only causes the airplane to roll back to level flight?!?! Unbelievable. I must admit that in no way was I attempting to create this type of flying characteristic. All I was trying to do was create a wing that stalled at a slower speed and didn't have any bad wing drops during a stall, never did I expect this type of characteristic!

I also created two separate noses that can be interchanged easily via two BBQ skewers. I'll post some pics of this as well, basically one for the GoPro and the for flying with no camera.

These flights were flown with the batteries attached under the swappable pods just like the bloody wonder. I am still waiting for some electrical chord on order from Hobby King to allow the batteries to be installed in the fuselage. If you wanted to use the fuselage for payload (candy bomber etc.) there would be a huge amount of space inside with the batteries out under the pods.

Next up: Redesigning the vertical stab and rudder, and engineering and building the mini nerf football bomber drops to be mounted between the fuselage and power pods on either side under the wing...

Now for the pics and video you've been waiting for. I'll post the pre flight pics with the two nose configurations followed by the videos. On the maiden flight at about 2:30 you will see some stall testing, at 4:30 and 6:40 you will see some of the rudder flutter. It was late in the evening with an overcast sky so its a little hard to see an all white airplane. Once the rudder flutter is fixed and it is in its final configuration paint will be in order!

 

[flyin201]

Before I forget, this has the same electronics as before, for these flights I was using 1600 mah 3 cells. The plan is to run it on a single 3000 mah 4 cell (on order) which should give me sufficient flight times and plenty of power. All the flights in the videos were run at half throttle so power is not an issue now, but I do need to keep up with a Mig 15 if you'll remember from previous posts. Also on order are some 8X6 props, currently running 8X4's.

 

[eagle4]

absolutely fantastic mate. What sized motors are you using? it looks like it flies great. I wonder how much payload you can get it to carry.

 

[flyin201]

New vertical stab and rudder installed and works great, all of the previous rudder flutter has been eliminated. I also min waxed it and painted it, going for a fire bomber type theme but mainly I just want something that is highly visible. Now I'm just waiting on some components so that I can mount the battery inside, still running it with two batteries mounted underneath the power pods, which almost created a disaster today. While doing a tight loop, the battery on the right motor popped off! I was lucky for 2 reasons, 1) it was the right motor, had it been the left motor I would have lost power to the receiver and that would have been all she wrote, and 2) because the batteries are out on the power pods, once I lost that battery cutting power to that motor, I inherintly lost the weight on that side as well causing it to be lighter on that side. To my shocking amazement the airplane was still controllable and I quickly set up an approach to landing and made a nice gently touch down completely shocked and amazed that the airplane had not met it's untimely demise. It also seemed to have plenty of power on one engine, I could have climbed back up if I had wanted to! The battery however shot in the ground like a lawn dart and is quite bent up. Not sure if it's still useable or not, maybe some of you guys might have some insight on that? Unfortunately I forgot my headband for the GoPro so I didn't capture it on video, however I did get some inflight video so I will post those once I get them uploaded. Overall very pleased, couldn't be happier!



This picture shows it with the flaperons down. With the under camber plus the flapperon it really allows it to slow down nicely.

 

[flyin201]

absolutely fantastic mate. What sized motors are you using? it looks like it flies great. I wonder how much payload you can get it to carry.

NTM 28-26 1200 kv motors, same as recommended for the Bloody Wonder.

Anybody think this batter is still safe to use? A little crunched up but otherwise intact, unsure how the inside is though. Definitely hesitant to do anything with it.

 

[flyin201]

Alright folks, here are the videos. Going to try some new angles when I get a chance, maybe later today. The third video is mostly full throttle acro haha, enjoy!

 

[flyin201]

Last two, a little different perspective this time.

 

[flyin201]

I finally had a chance to chase one of my brother's ducted fan jets at my parent's house for the holidays and it performed beautifully! Only trouble was once we were getting used to flying together and matching speeds the F-86 crashed. Oh well, I continued to fly on and made up my own fun, dive bombing the back yard!

 

[flyin201]

Here are some basic "plans" I drew up in Cad Touch on my tablet. Really its more just dimensions than actual plans, but I figure if you've built dtfb airplanes, just pictures and these very basic plans will be enough. I plan on building another one and documenting it better along the way so I can publish an article here on FT. My current one crashed and will need to be rebuilt all due to a receiver lock out, however I did manage some good video prior to the incident.

 

[ClearSkiesCalmWinds]

Very interesting plane. Hmmm. Hope to see more of it as it develops.

 

[flyin201]

A few snapshots from the footage before the crash chasing two Bloody Wonders and an F-86 EDF. I couldn't be happier with the flying qualities of this plane, however it is very hard to keep other aircraft in frame without any FPV gear. That will probably be next. I should note in this final configuration I am using a single, 4s 3000 mah battery mounted inside the fuselage rather that the two smaller batteries mounted under the pods as the previous versions had.

 

[flyin201]

And of course here are its final 3 flights, the first video is chasing one Bloody Wonder, the second two Bloody Wonder's, the 3rd is chasing an F-86 (and ultimately its crash) and the final video is a frame by frame video I made of the F-86 doing a roll and a very close head to head pass with a Bloody Wonder. Enjoy!

https://www.youtube.com/watch?v=AnrJrDp17ks

https://www.youtube.com/watch?v=DAd0TAZKh28

https://www.youtube.com/watch?v=dZvocNlNp7Q

https://www.youtube.com/watch?v=HCHrSJrKZCo

 

[ClearSkiesCalmWinds]

Very cool footage! Skills.