Knight's Trebuchet - a simple, quick, Scout trebuchet

I designed this simple trebuchet  as a more stable, robust small trebuchet. The two opposite side frames are braced against each other so it doesn't need guy lines, which is the main problem with the older trebuchet design on Ropes and Poles. The Troop Scouters of the recent Gauteng Scout Wood Badge course at Arrowe Park tested it out and verified that it works (two of the patrols promptly ganged up on the third to send a shower of over-ripe tomatoes across to them). The theme of the Wood Badge weekend was 'the Knights of Gauteng' so this is the Knight's Trebuchet.

Two patrols used a traction rope as per the drawing below, while the third patrol used a rubber tube, pictured above. All three worked successfully.

Here are the sequence drawings for assembling this trebuchet:

1. Build one 'A frame'- make sure there is enough space at the top for the throwing arm to rest.

2. Tie the base lashings of the second (yellow) 'A frame'/triangle and attach it to the first A frame

3. Lash the top of the yellow A-frame, making sure the crossing lines up with the green A-frame

4. Lash the two base poles on to the two frames.

5. Attach the throwing arm, which is lashed onto it's axle. Rest the axle in the forks on the top of the a frames, and 'mouse' the top of the fork to prevent the arm jumping out.




This trebuchet was tested with and without a sling.

The SketchUp model is available for download HERE.

Lightweight rafts - Kon Tiki Chairman's Challenge 2011

 

The annual Kon Tiki Chairman's Challenge was held all across Gauteng province recently. The top ten teams from Kon Tiki in March were challenged to participate. Rather than the normal race down the Vaal river, the challenge this year consisted of building a raft and completing a mobility challenge at four different lakes across the province, starting in the East at Arrowe Park, then on to the old quarry at Eastleigh Sea Scouts, then Emmarentia Dam and ending at in the West at Gilwell in Florida.

The rafts were all lightweight and designed to be quick to assemble, because this would have to be done four times. Points were also given for  advertising Scouting on the vehicles used to transport the rafts between the four lakes. Two groups, 1st Kengray BK and 1st Kempton Park,  built rafts with light plumbing pipe outriggers, pictured above. Most other troops built very light 6 barrel rafts as shown above left. The competition was won by First River Trail Scouts.

More photographs are available on the Kon Tiki Facebook page.

Robin Hills Portcullis Gateway

Robin Hills Scout troop built this portcullis gateway for their campsite at Kontiki 2011. Two A-frames support a gate that slides up along the slope of the front legs. This gate is a much bigger and sturdier portcullis than the one I blogged about back in 2006. The SketchUp model is available for download here.

Here is the gate closed at left, and open on the right.

A photograph of the gateway. Robin Hills went on to win Kontiki

JOTA JOTI Towers - 2010

This weekend sees the 54th Jamboree on the Air and 15th Jamboree on the Internet (also the sixth year of Ropes and Poles). Here are some photographs of Radio masts and towers built last year by various troops. You can sign up at Jotajoti.org to post pictures and a report of your own JOTI JOTA event, and also to see other groups' pictures as they are posted. Our camp at Arrowe Park will be posting pics and updates there, as well as on Twitter as @arrowepark .I'll also be on IRC during the weekend as RopesnpolesZA.

Giant box kite

A few years ago, our group held a joint event between the Cubs and Scouts, where we flew kites. The Cubs completed the requirements for the Cub Kites interest badge, while the Scout patrols held a competition to see whose kite would fly highest.

The biggest kite on the day was this box kite built by our Group Scouter and his son. It used cane from our Scout grounds for the frame, sisal lashings for the joints, and plastic rubbish bags for the flight surfaces. Because Benoni is 1600m (7000ft) above sea level, the wind needs to be fairly strong before a kite will fly well, but this one did get into the air a few times.

Box kites were invented in the 1890s, and were an important step on the way to the invention of heavier than air aircraft. NASA has a page with a good explanation of the aerodynamics of box kites.

Scoutmaster podcast #86: Kontiki and World Jamboree interview

Clarke Green from Pennsylvania runs a fantastic resource for adult leaders at Scoutmastercg.com. I recently spoke to him about my trip to the World Jamboree, as well as Scouting here in South Africa, concentrating on Kontiki. You can listen to the podcast, which is out today and available here.

Here are links to some of the things discussed on the podcast:

South Africa:  9th Benoni is my home group. Phoenix Rover Crew has a website here. Here is the blog of Joy Hutchinson, our Cub Pack's Akela. This is the South African Scout Association website (and Twitter account) with a special section on South Africa's contribution to world Scouting.

Kontiki: this is my raft category at Ropes and Poles, and this is the official Gauteng Kontiki website (here is the Western Cape one).

22nd World Scout Jamboree in Sweden: here is the official site. I kept a blog for the Drakensberg troop here, and the South African Contingent Management Team had a blog here.

Finally, if you're a new visitor to this site, welcome, and you can subscribe for email updates here, or to the RSS feed here. Likewise, if Clarke's blog is new to you, you can subscribe to email digests here, the podcast here, and the RSS feed here.

Dutch / Flemish method for round Lashing

Round lashings seem to be tied with many different methods. According to the Dutch Scout wiki, this is how the Dutch speaking Scouts do it - with turns that run around the poles in both directions and are bound with a reef knot. Earlier this year I posted about the German round lashing, which uses a simple-lashing-like binding to join two poles, and this is yet another variation. The lashing itself is explained like this (please excuse my rough and ready translation):

• In the Netherlands it's customary to begin with a clove hitch around both poles. In the Flemish Region, the middle of the ropes is just laid over both poles.
• Take one of the ends (a) once around both poles, after that, take the other end (b) over the end and around until it comes out next to the other end (at c).
• After this, continue alternating between the two ends.
• Arrange the ends so that the crossings happen between the poles (on the 'flat side') and there are only single ropes (with no crossings) on the side
• 6 to 8 turns are used
• End with a reef knot tied with the two ends, on the side of the two poles

Sourced from the Dutch scoutwiki (English Google translation here)