TB1100 hot wire cut FPV Plane

Some time ago I crashed my Radian FPV due to range problems with the EZUHF. At that very moment I decided that I needed another plane to do FPV flights with other than my beautiful Radian. Flying through trees and getting caught in branches might give a kick and an adrenaline rush but I didn't think the radian was worth it.

So I sat down at the pieces and started thinking

1. I broke the spinner and had to order a new one. Also, when the prop is spinning it ruins your image. My new plane had to be a pusher

2. I like to search for and fly through holes and gaps between trees. The plane needed to be small enough to do so. At least with a wingspan smaller than 120cm (47.24inch)

3. One of the problems with the radian is that there is not alot of space to put your stuff. This had to be improved with a bigger fuselage.

4. I wanted to try out the magical A-tail. To do so I needed a plane with two booms going back. "Hey, a twin boomer would do the job"

5. I also wanted to improve my hotwire technique so it would be mostly a hotwire cut plane.

With these ideas in mind I started building and soon had a prototype finished. 

 My exitement didn't last long because as soon as I went out to test it, it didn't even get off the ground. When I picked it up and throwed it, I had to maintain full throttle to even let it keep it's altitude. It was either to heavy or the fuselage was too wide. After ripping off the landing gear I tried to fly it again and eventually was able to persuade it to climb a few meters. But it just didn't have the power I needed. I came to the conclusion that the fuselage was too wide. There was only about 2inches of the 10 inch propellor sticking out on the sides and I simply knew that this was the problem. The elevator and rudder feel weren't to my liking so I diched my idea of an A-tail and went with a normal tail (one horizontal and two vertical stabilizers) So I narrowed the fuselage and hung it underneath the original wing since it was alot of work to redo and the wing was still in presteen conditions (for my standards) 

 This one flew much better and soon turned from being a prototype into my finished plane. I named her Felicia  because I like to give my planes nicknames.

flight video:

because she flew so good I kept on flying her and soon she wasn't as pretty as she was before and started to weigh consideraly more due to gluing her back together after countless crashes. I wanted a new plane to fly around and also change some of the things I didn't like so much about the version1. So I fired up my hotwire bow and started cutting.

First of all the nose. I cut off a piece of 8cm thick insulation foam ment for floors. A little longer than the 8cm I needed for the nose. After cutting it I started to make the front and the back perpendicular to one of the sides. I used two metal 90° measuring tools to do so, I drew a line perpendicular to the straight side and fastened the two tools alongside of this line.

Then I took the bow and cut it off.

I did the same on the other side and cut out the rest of the nose, no piture here for reasons you will see later on in the article.

Next in line was the fuselage. I cut off a piece of the same insulation foam, a little longer than the 60cm I needed for the fuselage and repeated the above to make the sides perpendicular and in the process cut the foam to the 60cm length I needed. then I took the templates I used for the V1 because the fuselage on that one was just perfect. I put them on both sides of the foam and started cutting. Starting in the middle going to the side and then downwards to cut the rest of the fuselage and a second time starting in the middle, going to the side and going up. the outside is quite easy so I didn't take a photo of the process.

Taking out the finished fuselage

Time to sand

I didn't throw the center piece away because it is usefull to center the wing on the fuselage (it has the exact same shape as the inside of the fuselage.) So I glued the pieces together and layed them aside.

Now it was time for the wing. I really liked the way the version1 flew so I re-used the templates of the original wing and cut the center piece of the wing out of foam. It is about 60cm wide, mine turned out to be a little shorter because I forgot to make the sides perpendicular to the bottom before I cut it to size. 

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First of all I used toothpicks to hold down the templates

tThen I started cutting

Doing one side at a time, this way there will be a seam but I thought to make this seem in a place where I could sand it away fairly easy. Be carefull not to go to fast otherwise the bow will cause the wing to be less wide in the center of the wing.

seem sanded away, wing looking nice.

Then it was time to make the wingtips, I cut out another 60cm wide wing and cut it in half, I then cut it to a shape much like the Bix3 wing since this shape tends to be self-stabilising (as I heard) 

Then I glued the wingtips to the center piece of the wing, It appears to be a nice looking wing, I'm very happy with the way it came out.

Then it was time to start turning it into a twin boomer, I went to the hardware store and bought myself a piece of 1cm by 1cm square rod with a length of 210cm. I then cut this rod into pieces of 70cm to make 3 pieces so I had one rod as a spare.

After pickiing out the ones that looked the nicest, I measured the middle of the wing and glued the two booms underneath it with about 30cm of separation. This allowes me to fit a bigger prop if I needed to.

 After this it was time for the horizontal stabilizer. I took a piece of 6mm depron and cut out a piece measuring 32 (30+2*1) by 11cm.

And glued it to the back of the booms. I also cut the elevator out so I didn't have to hassle with cutting it afterwards.

to give the sabilizer a little more ridgidity, I added a piece of small wood I had laying around to the front.

 Now for the vertical stabilizer. The original plane had some tracking issues, after adding a piece of depron in front of the original stabilizers this problem was solved. 

Knowing this I did the same on the new plane, only cutting it out of a single piece instaed of two to make it look a bit better. I also increased the height of the stabilizer and gave it a more sleek look. 

 After gluing the servo's in, making my connections and testing eeverything it was time for the maiden. I put a SD-card in my pilot-HD pressed record and threw it into the air. Notice the camera sticking out a bit at the front? Remember that.

The plane flew very good and I soon got familiar with it. Maybe a little too familiar because as I came over to do a low pass alongside a tree, the left wing hit the tree, causing my freshly build plane to spin nose first into the gravel of the road I always stand on to fly. The nose exploded and my video link went straight to black. When I arrived at the crash scene I found my plane in pieces. And worse, my nice Pilot-HD camera had broken. Remember the lens sticking out?

The connectors got ripped out of the pcb-board taking a little bit of the boad with it. I'ts a shame that this happened, if it were just the connectors that broke I could have fixed it. The biggest issue was that because the camera had broken, there was nothing on the SD-card but a corrupted file. 

But no time to waste, I saw this as an opportunity to upgrade from a CMOS to a CCD camera and ordered one from aliexpress, 12bucks with free shipping, cheap as beans. http://www.aliexpress.com/item/Free-Shipping-1-3-700TVL-PAL-3-6mm-Mini-CCD-FPV-Camera-for-RC-Quadcopter-Drone/32288608584.html

As I waited for this camera to arrive, I started repairing the plane. Basically all that broke was the nose piece. So I started building a new nose. Again, starting with a piece of foam that I straightened. But I used different templates this time. The new nose was going to be longer and less round, but still a little narrower in the front. So I made some new templates and started cutting. 

Nose cut out and reeady for sanding.

I integrated about an 7° downward angle in the process to angle the camera down ever so slightly.

 After sanding, the nose was ready to be fitted.

 I also added a piece of foam in the front with a hole in the middle for the lens to go through.

Then it was time to add the top plate. I used a piece of 6mm depron which I glued onto the part of the previous plate that wasn't destroyed.

I also added a bbq scewer for extra strength and some magnets to hold it down.

After this I turned the fuselage around and cut the edges flush. 

As I like to give my planes names I asked my gilfriend to say the first name that came into her mind. After coming up with the name "Gizmo" it was time to give it a paint job.

Isn't he a goodlooking fella?

The flight video is not in the same quality as the video of the V1 because I have to use a little keychain camera now since I lost my Pilot-HD in the crash. But still, it is better than nothing, enjoy. Filmed from the front is one of the first flights I did with this plane. Filmed from the rear is one of the flights I had when I had more experience with the airframe. 

 I noticed that because of the shape of the V2's wings it seemed a little less stable. Not that I mind it because I rarely fly straight but I guess I'll stick with the straight edges instead of the new shape just for an easier build. Instead of cutting one of the wingpanels in half and shaping them I can simply glue two winghalves together and be done with it. 

Plans with the exact dimensions: Plans TB1100