[ARP]

Joe,

On the latest splitwing design the intention was to use seatbelt type webbing instead of a cable for the leading edge. An external Mylar sheet is wrapped around the L/E and held in place with Velcro. When removed the Mylar rolls up to fit in the 2m bag. In a way I have used nature's own method of wing construction as feathers are held together in the same way.

[ARP]

Attached picture shows wing at rest and top rigging under tension.

[Bob Kuczewski]

Thanks for the pictures Tony. They make it much clearer for those of us who've never seen one in person.

[ARP]

The attached picture shows that the Split-Wing main sail could be adjusted by the ties on the trailing edge to the rear rigging cable. The Porta-Wing uses a similar rear rigging cable which might allow for the same arrangement? However the amount of sail billow would make it difficult to get the correct alignment.

[Bob Kuczewski]

Great photo Tony!!!     

It makes me wonder ... when will one appear at Dockweiler?

[ARP]

Hi Bob,

The wing design is based on sailboat rigs and could easily be duplicated if someone wants to build it at Dockweiler. It flies very slowly with an L/D or around 10/1 . Complete novices were able to fly it without much instruction. If you can get two sets of sailboat sails (Jib & Mainsail) and build a simple cruciform airframe and add a control frame it could be flying in no time.

I will send sketches if anyone wants to try.

Tony

[Frank Colver]

Hi Bob,

The wing design is based on sailboat rigs and could easily be duplicated if someone wants to build it at Dockweiler. It flies very slowly with an L/D or around 10/1 . Complete novices were able to fly it without much instruction. If you can get two sets of sailboat sails (Jib & Mainsail) and build a simple cruciform airframe and add a control frame it could be flying in no time.

I will send sketches if anyone wants to try.

Tony

I will pay for the materials if someone wants to make a serious project to build it and fly it. Especially if it is in Southern California so that I can physically help with the project (ideas and parts machining etc.) and also possibly fly.

Frank Colver

[ARP]

Frank,

Here is a modified plan view showing the addition of battens in both main and jib. I used 2" o.d. 16guage aluminium HT30TF (drawn). !7guage should be OK and allows telescoping of tubes for sleeving and reinforcement. If you use HG tubing as close to the sizes as shown it should be fine.

Span is 30' and keel is 17'6".

As I will have no control over build or materials used no liability is accepted by me or guarantees offered to its suitability for flight, etc.

[KaiMartin]

The attached picture shows that the Split-Wing main sail could be adjusted by the ties on the trailing edge to the rear rigging cable. The Porta-Wing uses a similar rear rigging cable which might allow for the same arrangement? However the amount of sail billow would make it difficult to get the correct alignment.

The configuration of sails at the split-wing differs significantly from the way they are arranged on a sail boat. The jib of a dinghy does not align with the main sail. While both sails are set to about the same angle of attack, they are shifted down wind. The clew of a jib tends to be fixed about half the sails a cord downwind of the mast. Most modern designs pull the aft of the head sail even further to the stern and fly a genua. See the rig of a flying dutchman:

As you can see, this arrangement results in a biplane configuration with the two sails stacked above each other rather than down wind. The flow field of the sails is closely coupled. As a result the pair can be operated at higher angles of attack than separated sails.

If a split wing is intended to benefit from the same aerodynamic effects as the main sail/genua combo it should probably go for a more stacked position of the wings. I am not sure how this would affect pitch stability. Thorough analysis and model testing would be mandatory.

---<)kaimartin(>---

[ARP]

Kai,

Yes various positions for the jib/Genoa were tried and they all worked. The latest design I am working on does overlap by quite a bit. The jib/Genoa are near full span but the Mk3 is about half span but uses tube rather than cable L/E. The Mk1 sails were not on the same alignment, as the keel angle provided the biplane separation, which still provided a close coupling, enabling high angle of attack without stalling.

Mk 2 attatched:-