tenacious101010

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I am posting this to help others and hopefully learn from others about in-flight video techniques.
I have been working with a video camera mounted on my planes for a while. My son and I were invited to fly at the MacDill AFB Open house a few years ago. We decided to fly our Great Planes P-6E Hawk. It is,or was powered by a Zenoah G-38 at the time. I made a foam box for the medium sized video camera and put it between the top wing and the top of the cowl. The vibration was terrible, such a shame since we were making strafing runs on the Blue Angels sitting on the ramp. This began my quest for getting good video so if we were afforded the opportunity again, we would be ready. Here is the attempt that I described earlier.
Denny

http://www.youtube.com/watch?v=rnlhcE2okdo

tenacious101010

My Feedback: (97)

It became obvious that mounting a video camera on an airplane with gas or glow motor was not going to be very easy. I came to the conclusion that the less contact the video camera had with the vibrating airplane, the better the video would be. I began looking at a lightweight rod sticking out from the back of the plane to mount the video camera on. One rod would not work, it took three to keep the camera from swaying on the end of the single rod. Luckily I discovered the small key cams. The carbon fiber rods were visible in the video and it was not easy attaching the rods to the plane. I finally came to the conclusion that I wanted a towed camera using fish line or similar. I found a Stryker replacement body at a swap meet and based my towed video vehicle on that. I added elevons, vertical stabs without rudders, a reciever, battery and a servo operated tow line release mechanism. I mounted the key cam on the stryker and set the CG the same as a powered stryker. We finally had a decent way to not only get video of the place we were flying, but also we got great video of out aircraft from behind too. Heres the first event we took the video platform to. The sun was way too low to get good video quality, but we proved the concept.

http://www.youtube.com/watch?v=2AfxvijRYUg

tenacious101010

My Feedback: (97)

More experimenting and it was obvious that the faster the plane, the tougher it was to keep the Stryker stable behind the towing aircraft. Giant scale %1s and such did not work so well. It took a lot of work for the person flying the Stryker to keep the towing aircraft in sight. We found that the Stryker was much more stable when a lot of up trim was set and we would get a lot less slack in the line. We were invited to fly at MacDills Open House again and were ready this time. By this time I had converted the Hawk to electric power, vibration was no longer an issue so I made a camera mount that could be controlled with a separate controller. The following is the video of that event.

http://www.youtube.com/watch?v=0suYE...3HHjGbotzidNAQ

http://www.youtube.com/watch?v=skRUR...layer_embedded

tenacious101010

My Feedback: (97)

The next time we tried the Stryker was with a 1/4 scale Fokker DR-1, during this flight, which was a lot slower than any of the other aircraft we had towed with. About halfway thru the flight we gave teh stryker even more up-trim and it tracked the next three passes around the field with no operator input to the Stryker. We proved it was possible to tow a erelatively stable uncontrolled video platform. Here is the video of that flight.

http://www.youtube.com/watch?v=jRhdC...layer_embedded

tenacious101010

My Feedback: (97)

Since this flight I have made several more towed vidoe platforms and will be testing them hopefully tomorrow. I will post the results. If anyone has any experience towing anything like this, please share what you have learned.
Denny

tenacious101010

My Feedback: (97)

I will be using a much thinner tow line so it wont be so visible. The foam plane beefed up with carbon fiber rods is an attempt to get the camera higher, away from the tow line. I am thinking if it is not so close and so parallell, the line wont be as visible. Thje last picture is a wide angle 120 degree video camera, tomorrow will be the first time I will get to test it out. Being wide angle, I think it will be easier to keep the tow plane in sight and will just make for better video. The beauty if the foam pool noodles is that the camera is well protected. Here are some pictures of the vehicles I have made to test. Anyone wanna bet which ones will work the best?

thailazer

Interesting concept! Have you thought of just making a drogue chute with the camera in the middle. That seems to be the most stable design for aerial refueling of fighters from a tanker. You could put a weighted skeg on the bottom to keep it upright and a fishing swivel to avoid line torsion.

bogbeagle

Some fascinating ideas.

A drogue might be very good ... maybe a "windsock" design?

I fancy having a go at this.

thailazer

I would think there is a fair bit of research into these things! I will try to attach a pdf.....

tenacious101010

My Feedback: (97)

The drouge chute method could work. I spent 20 years in the Air Force as an Aircraft Weapons guy, there was a towed target that was used for shooting at with other aircraft. They were towed aloft attached securely under the wing, then released and the cable reeled out to the proper distance. They looked like big silver darts. I am not sure how stable they were longitudinally. The bigggest issue with the drouge is the very high drag, releasing or bringing the unit back and I believe longitudinal stability. I am sure these could be overcome with some experimentation.Based on my experience, I have pursued two types of towed vehicle.
Type 1, lifting surface, this type has a large wing area and flies high above the towed plane with the video looking down on the tow plane. I like this video the best as compared to looking up at the towed plane. For the most part so far to achieve longitudinal stability, the towed platform has had to be controlled ( with reciever and live control surfaces). So far, I have balanced these vehicles and set the CG so they will glide back to earth. So far, this type releases itself from the tow plane and tow line, leaving the tow line trailing behind the tow aircraft. Landing with this type is difficult thusfar because the lifting property of the vehicle wants to lift the tail of the landing plane. Even with the big hawk, this has happened the two times we tried to land connected. The goal for me is to have this towed vehicle stop flying just before the towed vehicle does so it will not cause the nose overs and yet still keep the tow line taught and land stably behind the tow plane. My goal is to build a large lifting surface vehicle that is not controlled, that way one person can do the flying.
Type 2. The trailing type has very little lifting (wing) area and trails below the towing aircraft. This type so far has been very simple in that I have not used "Live" control surfaces. Longitudinal stability is an issue, but not as bad as the larger winged vehicles. The CG is not so critical on these types so far, but as I get a better compromise between a winged lifting type and a trailing type, I believe the Cg will be more important.Thusfar, this type is towed and still attached at landing with the trailing vehicle touching down on the runway and losing lift before the towing plane does. The last test, I installed a release mechanism on the tow vehicle to release the tow line in case of emergency and to see if I could get the trailing vehicle to land softly enough to prevent damage to the vehicle and video camera. The trailing types are also much easier to build. Using the foam pool noodle, the camera slides nice and snugly into the hole and the foam protects the video camera.
One critical design consideration is the location of the tow line connection to the towed vehicle in the vertical. Connecting it too low makes too high of an angle of attack for the lifting surfaces, somewhere just at center or slightly lower seems to be the best location.
Denny

tenacious101010

My Feedback: (97)

We had planned on using our Nexstar to do the test towing but as the throttle was advanced to take off, smoke poured from the ESC. We used another, but much faster flying plane to tow with. I started out with the small flying wing and it did so well, we didnt even try anything else. The video camera that was on the vehicle was not a working camera so we didnt get video. The second flight, we put a functioning vodeo camera on board. Upon review the working video camera didnt live up to its name, we got audio only. It was amazingly stable at various speeds. I was thrilled with its flying characeristics and plan on makeing a few more of these with slight modifications. One thing it did was fly lower than the tow plane so I will be working to get it to fly higher.
Denny