Chase Cam construction thoughts

[leshoman]

Here are some pictures of the best chase cam so far.  I is made from polyproplene cardboard, sign board from local office supply 19"x15" x .3 mm sheet, 3/4" x 1/16" alum strip from local hardware store, a 1/4" x 6" eye bolt and GOOP.   never used goop before but it works for this project. Made the vane part as large as possible from the 19"x15" sheet.  General rule is to keep everything as light as possible.  Camera will drop about 45 degrees from where attached and longer tow rope more it will drop. I use a 1/8" cord and a 5/32" cord.  Needs to be stretchy, not something that will not stretch like braided fishing twine. Nylon cord seems to work and parachute cord. installed small safety wire from top of eye bolt to cone to help strengthen.  The ones i made out of 4mm polyproplene cardboard were to heavy but i was using 3/4" x 1/8" alum. strip also.  It can be to large and too short on the alum strip.

[Bob S.]

I have seen it is important to know how high above the mounts you pull from...
Eyebolt looks to be about 6"??

[stevejahr]

That is crude... but seems to work reasonably well based on your results.

The raising of the tow line attach is an interesting twist.  This would not have been my first thought but I can see that it may have the advantage of moving the tow line out of the camera field of vision.  Use of a tube body rather than the strip would of course reduce weight and increase stiffness and eliminate the need for the extra cable reinforcement.

The tow line angle of 45* matches expectations as the tow line is doing all the lifting here.  It will angle back will be based on the balance between weight and drag.

My thought here is using a lifting vehicle (ie airplane) to carry the camera would be more efficient and cause less drag (and thus yaw) on the host airframe.  You could still use the displaced tow line attachment, so long as you get the right distance/height for the displacement.  The tow line should make a straight line to the CG of the camera platform at cruise.

[Bob S.]

There will always be those who propose improvements without putting any effort...

[ParQld]

Les this is a very clever invention, your videos are excellent using the equipment you have developed, very inspirational to  all. Keep the videos coming they are great fun to watch and very informative. I look for ward to my regular geography leasons of your region.

cheers Paul

[Sam Buchanan]

Les, that is one clever little rig. You have put in a tremendous amount of research/time and the results are the proof.

I have no suggestions for improvements and defer to your knowledge of The Chase Cam, you know far more about how to trail a camera from your plane than any of us.    

[leshoman]

My ideas are not original. In 2012 i was at Oshkosh down in the Ultralight area and saw a powered parachute take off with, I did no what it was at the time, a chase cam behind it with a gopro camera.  I had just bought my first gopro and thought to myself i could do that behind my eagle.  As i thought about it i decided the prop turbulence and drag would be a real problem.  This year at Oshkosh i met and was talking to Dan Grunloh, from Experimenter Magazine, We talked for some time and towards end of conversation, i do not remember how we got there i mentioned the idea of a chase cam but did not think one would work behind a airplane.  Dan said he knew just the person to answer my questions, John Vinning fly's a powered parachute that has lots of experience with them behind his rig.  Turns out John was the one i saw in 2012.  Talked to John and he showed me his chase cam.  He thought because of our increased speed it may need to be smaller than his.  Now if you don't know it is very dangerous to let me see something that i am  interested in or it is a remote possibility of being used in or on something i am trying to do. My first attempt mirrored what John had done.  It did not work very well but started the ball rolling.  I started the first one out the truck window at speeds we fly.  Moved to the eagle and found out about the drag forces, effect on flying and effect of flying machine on chase cam.  Moved it inboard, very concerned about prop wash, so far so good.  Have added wing mount.  The Chase cam i am flying is model 12, modification A.  It seems to be best so far and in calm conditions does well.  I am working on model 14, notice no 13, i am like Leonard, skip 13 for luck, And should have it flying in next week or two. it has ailerons and a stabilizer to keep it level during gusty conditions.  Has a way to turn stabilizer off on on, during flight so it i can have it follow my turns.   
  Problem with any type of lifting body is speed changes. lift near stall versus lift near red line would vary unless someone knows something i don't.  The only way i know to get it to follow directly behind is to go full controls and then have guidance system that targets spot on eagle and keeps it there.  Have done some investigating on this and it is possible but i do not have the time or resources to make it happen now.  
  If you have ever flow formation or reasonably close formation you know during non calm weather the machines do not go up and down at same time, due to wind currents, and that is two machines of similar weight. When you have one machine that is a small fraction of weight and size of other, movements, even when they are in close proximity to each other, are not the same.  Most people buy beer, go to the movies, buy another log for the fire, i get ideas and spend it on weird stuff, chase cams and components to make another one, not that there are not a few more things floating around in the shop and hanger.

[Dan_]

 The only way i know to get it to follow directly behind is to go full controls and then have guidance system that targets spot on eagle and keeps it there. Have done some investigating on this and it is possible but i do not have the time or resources to make it happen now. I

Les,

Have you seen these..?  

http://www.hobbyking.com/hobbyking/store/__38543__OrangeRX_RX3S_3_Axis_Flight_Stabilizer_V2_V2_1_firmware_V_tail_Delta_AUX_.html


I don't think lift is what you need, just enough surfaces to stabilize.  They would prolly be big enough to give you ample buoyancy in flight.



It does behoove that a tube for the main structure would be much less flexible...

[Bob S.]

I am of the opinion (Like A$$#oles, EVERYBODY has an opinion) adding electronics to a chase cam is totally unnecessary. All it does is make it heavier and adds drag. Two things an Eagle doesn't need! Les, your videos are excellent and shows your Eagle very nicely! But if you try, I hope you document your experiment for others to see! 
I seem to have misplaced the YouTube that documents another Chase Cam that I am using for my experiment.. It is much like yours using a triangle lifting surface but mine is on a larger base plate...for additional lift.... We shall see. 
As soon as the WX here allows, I will get out to the field and give it a flight test.

[leshoman]

Paul
My next model with ailerons has the triangle but also has a larger base plate for the ailerons.  I tried using large coke bottle tops turned backwards to cause drag above the chase cam to raise the unit. it somewhat worked but the tow rope takes a lot of eagle related movements out of the camera set up and with the added drag it added new movements in.  I did not find any success there.