Showing posts with label ITW 9ft Levitation Delta. Show all posts
Showing posts with label ITW 9ft Levitation Delta. Show all posts

Friday, March 29, 2013

Rapid Bay South Australia


Rapid Bay jetty on the Fleurieu Peninsula South Australia is the best dive spot to find Leafy Seadragons. These bizarre fish are related to seahorses and are only found in South Australia, nowhere else in the world.

We planned a 4 day trip to dive flat out and photograph seadragons but the weather had other ideas. The trip became a KAP trip due to strong winds ruining the diving.
A new jetty has been built to allow access to the crumbling old jetty where the seadragons live. Depth up to 10m but 6m mostly.

Second Valley jetty 10min up the road from Rapid Bay. We stayed in a holiday rental house here with a very short steep driveway. Had to be pulled out by 4WD after getting bogged in deep dust. Very embarrassing but the neighbour said it happens regularly.







Cape Jervis where the Kangaroo Island ferry docks.











Leafy Seadragon - we did get in for one dive and found 3 leafies making the trip worthwhile.











4 min video of our one dive

Monday, January 28, 2013

Line-pull ratios

After recording line-pull with 4 KAP kites in Bft 1 to 5 (2 to 18kn) I have worked out a rough estimate of line-pull ratios. The ratios are expressed as line-pull (lb) to wind strength (kn)

Line-pull Ratios (lb:kn)
7ft Pirate Rok              1:1
ITW Levitation Delta    1:2
Peter Lynn 2m2 Pilot   2:5
PFK Nighthawk            1:3


Which means the line-pull (in pounds) of the Rok roughly equals the wind strength (in knots). The Levi delta pulls half as much as the Rok and the PFK one third as much.

For example: In 12kn the Rok pulls at 12lb, the Levi pulls at 6lb, the PL pilot pulls at 5lb and the PFK pulls at 4lb. 


Rok and PFK in Bft 1-2. Insufficient wind for the Levi delta and PL 2m2 Pilot.

Four kites in Bft 3 

Tuesday, January 22, 2013

Line-pull measurements

The amount of pull on the line dictates which KAP rig can be used. I have started recording line-pull using an electronic luggage scale ($9 on ebay) to help with kite selection.

I have found that line-pull of about 3 times the rig weight is enough to safely lift the rig. So I need 7lb pull to lift my 1.1kg SLR rig. (Apologies for the mixed units, must start measuring pull in kg!)

Here is a clever interactive lift/pull calculator from Kaper e-zine. Plug in rig weights and see line pull and angles.

Of course line angle also matters. Deltas can fly almost directly overhead. At times the delta and rig can be in perfect balance leaving next to no tension on the line in your hand and zero movement of the rig. Perfect for sharp KAP shots. It's a magical moment, hard to believe it's possible.

My intention is to build up data for each kite in a range of wind strengths.
It's early days but it seems with the 7ft Rokkaku line-pull in pounds is pretty close to wind strength in knots. For example I would expect line-pull of 7lb in a 7kn breeze.

Here are two video compilations of kites compared in Bft 4 and Bft 2.
I'll do Bft 3 and Bft 5 when the conditions permit. I have tried Bft 1-2 but the Rok was the only kite capable of staying up.
Three kites compared in Bft 2

Four kites compared in Bft 4

Eventually I'll put together videos and publish a line-pull table for each kite separately in the full range of wind strengths.

Beaufort Wind Scale
Bft 1     1-2kn          Calm - Not enough to fly. Go diving
Bft 2     3-6kn          Light breeze - Rok will fly, others maybe.
Bft 3     7-10kn        Nice breeze - All kites will fly. Need to match kite to rig.
Bft 4     11-15kn      Decent breeze - All kites will lift rigs easily. Upper range for the Rok.
Bft 5     16-20kn      Strong wind - Too much for the Rok and Levi
Bft 6     21-26kn      Howling - Only the PFK will survive.

Thursday, January 10, 2013

Nikon D80 SLR manual rig

I recently upgraded to a Nikon D7000 for underwater photography so my original SLR, a Nikon D80, doesn't get much use these days. To reward the D80 for reliable long service and paying for itself many times over I thought it might like to go flying.

It's not the ideal KAP camera being quite heavy (672g body + 202g 18-55mm lens = 874g all up)
and it doesn't have an intervalometer but that didn't stop me. James Gentles makes a lovely little device called GentLED-AUTO which is an IR remote intervalometer weighing just 20g. I just happened to have one sitting around so it was time to give SLR KAP a try.

First step was to make a basic manual rig just to see if my kites could lift it.
I bent up some aluminium to make a rig similar to the vertical style Aurico autoKAP rig for the Canon S100. But this design, a single vertical support with an L bracket to mount the camera, was way too flexible for the heavier SLR. The spring like flexing would have had the camera bouncing up and down continuously.

Nikon D80 manual rig - 1090g

So I had to revert to the tried and tested double U style. This allows a light and stiff rig to be built using the minimum of material, but it means I needed to balance the camera in the bottom tray carefully following James Gentles guide, which I find much trickier than building the vertical style rig.

The bottom U tray needs to be wide enough, front to back, to accommodate the camera mounting bolt and the pivot holes on each side which are at the centre of gravity for the camera. With this camera/lens combo the centre of gravity is 24mm forward of the camera mount hole. The bottom U needed to be 40mm wide. The top U only needed to be 30mm wide to be stiff enough.




Amazingly the wind was perfect for a test fly on the day I made this rig. Sunny with a smooth onshore 12kn and the Levitation Delta had no problem lifting it all as shown in this video.

I was really pleased with the image quality compared to the Canon S100 partly because the heavier rig isn't blown around by the wind as much.

I have begun to realise that lighter rigs suffer from blow back resulting in angled horizons or more/less tilt than expected. I'll talk more about blow back soon.

Here are KAP shots using the D80



Saturday, December 1, 2012

First you need a kite.

To lift a camera you need a big kite with lots of pull. It also needs to be a steady flier and there are a few designs renowned for their KAP-ability.

PFK Nighthawk
The Paul's Fishing Kite (PFK) Nighthawk delta is designed to fly in winds as strong as 30kn. Most other kites would be looping and crashing by then. It has large trailing edge flaps, strong flexible fibreglass spars and a hardwood spreader. The KAP community has adopted the PFK as the strong wind specialist, but it will also lift lighter rigs in normal wind strengths.
This is my favourite kite, it just wants to fly and keep on flying no matter how strong. Tail usually not required but may calm it down a bit in strong winds and reduce overflying.

Lifting range
480g RC rig in 12kn - 30kn+
270g GoPro rig in 6kn+
NZ$140 from Paul's Fishing Kites - New Zealand




ITW 9ft Levitation Delta
For lighter winds 5kn -17kn, this big delta from In-to-the-Wind is my choice and a favourite of many KAPers world wide. It has more pull than the PFK but also starts to fly to the side and do power loops in wind speeds above it's range.
Flies at a very high angle and even over-flies in light puffy wind and hot days. Adding a tail reduces overflying and gives steadier flight. I use a 3m long tube tail.

Lifting range
480g RC rig in 8kn - 17kn
270g GoPro rig in 5kn+
US$75 from Into the Wind - Boulder Colarado




PL Pilot 2m2
This 2.0 square metre parafoil is made in New Zealand by Peter Lynn Kites. Peter Lynn is famous for making some of the world's largest kites.
Parafoils have no spars and pack up into a small stuff bag. They have strong pull but fly at a lower line angle like 50ยบ
Flies well without a tail but everyone else says they use one. May calm down side to side swaying.

Lifting range
480g RC rig in 10kn+
270g GoPro rig in 6kn+
NZ$96 from Peter Lynn Kites - New Zealand




Cody Box Kite
This was the first kite I bought for KAP and it was not all that suitable. Above about 16kn it flies out to one side and power loops. It has a narrower wind range than the above kites and take more assembly time but does have good pull. KAP range 8kn - 15kn
However it is an interesting kite in the sky and attracts attention. It flies well enough within its wind range.

A$79 from Kite Power - Geelong



UPDATES
18th Jan 2013: New kite added to the quiver.
Skydog 7ft Pirate Rokkaku

Feb 2013: Made a 2m white rokkaku

May 2013: Made a 1.7m yellow rokkaku