General

A place for discussions about anything

A new type of suspension

Hello KAPpers!,
I am new to this forum, having only been involved with KAP for the past year or so. My interests are combining images from KAP with ground-based geophysical survey to evaluate archaeological sites, as well as having fun! I enjoy designing and making equipment for KAP using engineering design software, 3D printing and electronics. Along the way I have developed a new type of suspension which is simpler than the classical Picavet: it incorporates only two bearings, is lightweight and folds up small, with no lines to tangle. This suspension maintains a constant angle of the camera with respect to the taut kite line. It incorporates two adapters: a tapered jamming socket at the top where I currently fit an altimeter, and another adapter flange at the bottom for attaching a camera or a panning camera unit.
I have just launched a website with descriptions of these gadgets and my first modest attempts at aerial photography and aerial video:
Go to www.aeronaut.org.uk


Comments

  • Extremely interesting suspension Mark - and lots of other interesting stuff on your website! Welcome aboard!

  • interesting design. You have some nice pictures on your website. You wrote ' this new type of suspension uses a twin-pulley arrangement to ensure that the camera maintains a fixed angle with respect to the kite line; a taut line generally being a stable reference against which a camera can be aligned. ' A kite-line is not allways taut, the angle of the line can vary too, due to changes in wind speed. That is why conventional suspensions rely on gravity to keep the camera horizontal. What are the advantages of your system?

  • The kite line may not always be taut but, as regards the Picavet, be aware that the apparent gravitational vector is not always vertical either. As the line moves from side to side and accelerates up/down the Picavet platform will deviate from being horizontal because other forces will add to the gravity vector. When a kite is flying in 'clean' air at sufficient altitude the line angle is pretty stable and is sufficiently taut to provide a good basis against which my suspension remains stable. In addition, this new kit folds up and deploys quickly without a bundle of lines to get tangled as with the Picavet.

    I have also explored three methods for stabilising the suspension against rolling around the line axis against which, of course, neither the Picavet nor my design has any compensation. I plan to describe these ideas and field experiments at some point.

  • Am I right in thinking that the legal limit for kite-flying in the UK is 200 feet (60m)? If so, it might be prudent to avoid advertising the height to which you have been flying! Maybe things are different on the IOM or maybe you have permission to soar high. 200 feet does seem ridiculously low.

  • Thanks NZflier for the warning!
    Yes, I have only recently become aware of these regulations. I will be visiting the people at Air Traffic control to discuss kite flying on the IOM and possibly to seek a NOTAM permit to go above the 60m limit. I understand that this is what you must do.

  • 'First modest attempts' - too modest!!
    That's a seriously interesting piece of kit you've made.

  • Mark - 60 metres is definitely the limit though not often enforced. Some years ago I wrote a document about KAP and UK Law - no longer pointed to by the KAP Forum but you can find it here: https://zenoshrdlu.com/kapstuff/KAPUKLaw.html
    It's still largely accurate - not sure if the CAA permit document it mentions is still correct though. Back then you could get permission to fly at a certain place for 6 months at a height of up to 500' fairly easily (as long as it wasn't close to an airport or helicopter flight paths).

  • I have emailed the Isle of Man's Civil Aviation Authority to enquire about statutory limits on kite flying and to seek permission to vary these limits. Looking at the NOTAM map of Britain you can see that it is splattered with NOTAM alerts to the extent that pilots must feel like a fly trying to avoid a spider's web. We will see what the Air Police say, but in the meantime I see so many British KAP images on Facebook and elsewhere that must easily be above 60m, while doubting whether any applied for a NOTAM. Nevertheless, I want to be viewed as the good boy that smiles out from the picture of me on my Home Page.

    In the meantime, why don't we start a thread with Forum members listing the limits (if any) that apply in their own countries? I'll start with Austria which a friend in Vienna advises has a limit of 150m. However, their rules do state that you have to wear Lederhosen while flying.

  • edited October 25

    The current UK CAA Form for permission to fly above 60 metres is here https://caa.co.uk/uploadedFiles/CAA/Content/Standard_Content/General_aviation_and_events/Displays,_events_and_activities/PERMISSION%20Request%20KITE%20V3_fillable.pdf
    For me 60 metres is fine - I find low-level photos more interesting - they show details that high-level photos don't capture.
    Many of the aerial photos on the web are taken using drones which have a 400' limit in the UK - though the restrictions on where you can fly if you don't have a license mean no flying in towns or villages at all. I haven't flown my DJI drone since 2015 for that reason.

  • Admin,
    Thank you for the two links setting out flying regulations and for the limits on operating drones. I have spoken to our CAA people this morning and will report back later on the outcome of our discussion. It seems that I will not be heading for the prison after all!

  • I'm sure someone started a wiki years ago that included kite ceilings. Hans(elpedia) maybe?

  • Here in New Zealand the limit is 400 feet (120m), with the usual ban on flying within 5 km of an airport. But I have known people flying at much lower levels and outside the 5 km limit to receive a visit from the police because air traffic control has complained that they are flying too close to a flightpath (I am in Christchurch, and our international airport is just on the edge of the city).

  • The wiki page you are looking for can be found here.

  • indeed a very interesting and useful type of suspension ... you think it would work for heavier cameras?

  • edited October 26

    Love the KAP rig. I assume 3D printing is part of this fine work!

    Per kite regulations.... in the US....
    The US FAA regulations on kites can be found here: C14 FR PART 101 - MOORED BALLOONS, KITES, AMATEUR ROCKETS, AND UNMANNED FREE BALLOONS - https://www.ecfr.gov/current/title-14/part-101
    The regulations state: 14 CFR § 101.13 Operating limitations.
    **(a) Except as provided in paragraph (b) of this section, no person may operate a moored balloon or kite - **
    (1) Less than 500 feet from the base of any cloud;
    (2) More than 500 feet above the surface of the earth;
    (3) From an area where the ground visibility is less than three miles; or
    (4) Within five miles of the boundary of any airport.

    Seems simple... 500 feet....but....the scope or applicability for the regulations state:
    § 101.1 Applicability.
    (a) This part prescribes rules governing the operation in the United States, of the following:
    (2) Except as provided for in § 101.7, any kite that** weighs more than 5 pounds** and is intended to be flown at the end of a rope or cable.

    ....of the many kites that I own and fly....none weigh more than 5 pounds....most weigh less than 1 pound.... So my kites are excluded from this regulation on height .... but .... there is another reg.... 14 CFR 101.7 (a)....

    § 101.7 Hazardous operations.
    (a) No person may operate any moored balloon, kite, amateur rocket, or unmanned free balloon in a manner that creates a hazard to other persons, or their property. This the FAA catch all safety regulations..... in discussions with FAA (I have had a few) they acknowledge my kites are less than the 5 pound limit...but they point to 14 CFR 101.7 (a).

    So basically if you are flying your less than 5 pound kite at ANY altitude you can be cited as in violation of this regulations if your kite causes a hazard. Example - you are flying your kite at 150 feet (well below 500 feet and more than 5 miles away from any airport....you are still liable if a low flying manned aircraft hits your kite or kite line. (think helicopters and small planes).

    Helicopters can mess with your kite line....I know....see story and pictures (on flickr) here: http://kapforum.org/discussion/discussion/comment/16544#Comment_16544

    You can search this KAP forum and find lots of information under "safety", "safety box".
    WW

    Kite and KAP Rig Meet Helicopter - Helicopter Wins

  • As Jim (Wind Watcher) says, and as I mentioned in the NZ situation, you can be in trouble at almost any height if the authorities so decide. I believe, too, that some national parks and nature reserves ban kite-flying altogether as they seem to think it will scare away the local birdlife or whatever. This also applies to some recreation parks where the local council has decided that flying is undesirable, and I believe even some beaches in the UK now ban kite-flying. I'm not sure if this extends to small children with their little diamonds and deltas, but it seems a bit excessive if so.

  • There seems to be huge disparity in how formal regulations are configured worldwide and how local authorities actually implement them. For example in the UK 60m is the limit (thanks NZflier) rising to 300m in Finland (thanks Peter_L). I have submitted a carefully worded two page proposal to the Isle of Man Civil Aviation Authority and hope to hear from them next week with an answer.

    In Britain the Air Police are most focused on the drone nuisance. Early models had no altitude lock in their firmware, although I am sure that savvy owners can hack out this restriction. Drones became a problem here with them flying over the TT Races and have now been banned (the drones, not the bikes!).

    Yes, KAPjasa, my suspension can be used for a much heavier camera provided the bearings are suitable. In the current version the two spindles are polished 3mm brass rods, one end of each threaded M3 for captive nuts, the other end has a brass cap soldered on. The result is a very low friction PLA-brass bearing. With 100% print density I am sure it could support (and stabilise) a 1/2 kg camera. For heavier loads the suspension bar should be lengthened to better conform to the line angle. Also for very heavy cameras I suggest replacing the spindles with two 3mm I.D. ball bearings which are inexpensive. A revised 3D model and print file would of course be needed.

    My website will be including another project where I have investigated three methods for reducing roll of the suspension around the line - something that remains uncorrected in either the Picavet or my own design at present. There is so much fun to be had with this activity!

  • Attached are some pictures of a simple type of damper that reduces roll around the line. It fits into the TriTaper socket at the top of my suspension and comprises a pair of 10 cm polystyrene balls at each end of a 1 metre long, 4 mm carbon fibre tube. My first prototype was simply the two balls mounted on a single spar, but to my surprise the balls oscillated violently up and down at about 5Hz due to cyclic eddy shedding in the lee of each ball. Incidentally, this 'flutter' was found to be the cause of wing failure in early monoplanes when the change was made from the more strongly braced biplanes that they replaced. Anyway, I digress!

    In the current version flutter is prevented by bracing and bending the spar with monofilament line tensioned between four short struts that raise the balls above the line by about 20cm. The whole structure weighs 56.6 grams. Damping occurs by two effects: first, simple aerodynamic drag on the balls should the structure roll even when the line is stationary; secondly, as the line accelerates left-right across the line the aerodynamic torque on the (raised) balls opposes the inertial torque on the hanging camera assembly.

    In tests I found that the damping was too small and so larger balls are on order. Incidentally, egg-shaped polystyrene balls in many sizes can be found on the InterWeb and these would be more streamlined than simple balls.

    In the pictures my altimeter is

    stacked on top of the roll damper via a second TriTaper adapter.

  • Very interesting trials and ideas,
    I suggest to take a look also at some old discussions https://research-benton.ced.berkeley.edu/discuss2/index.php?p=/discussion/2129/self-adjusting-first-person-camera-rig FIRST PERSON key...
    and videos :
    KAP RIGS are an interesting matter where it is possible to try in several different ways; after MANY trials I'm returning back to minimum... at final balance we have to follow the wind, not to try to compete...
    trials with longer pendulum are in direction of more stable conditions in good conditions but when a sudden change occurs the swinging goes-on for too long time.... and putting weights at remote distance is increasing the energy when disturbed from original position...
    but for sure trials are also fun and this is needed for life good feeling

    wish you all the best possible
    SMAC from Italy

  • Thanks SMAC for highlighting your idea for a type of rig which is another type of parallelogram stabiliser, which is the same basis as mine.

    As you say inventing things is "needed for life good feeling" and indeed creativity is the greatest source of wealth. Comparing your and my suspension I am reminded of something an electronics friend of mine once said "There is no such thing as new ideas, only new applications of old ideas". Very true!

    Best wishes from a wet Isle of Man

  • Here is another idea for a type of roll stabiliser. It comprises a beam with weights at the ends to form an inertial body reference. Owing to this inertia, the beam tries not to move and when the suspension rolls it drives a differential gearbox to twist ailerons that bring the suspension back to vertical. It was attached to the top of one of my early camera suspensions.

    I have only done a very preliminary flight test which showed some tentative promise. However, it needs a larger inertia beam (longer and/or with more mass) and ailerons placed further out for it

    to work better. The three bevel gears were made by 3D printing.

Sign In or Register to comment.