We converted from UHMW to wheels - all 38 of them. This sounded like a simple effort, but it turned out
to be a major task. I couldn't find wheels that would stand up to the pressures we were experiencing so
I built them on a lathe. Being new to metal lathing, I found it a challenge to get the wheels true, but after
a while - I got the hang of it. Our first throw at our house turned out to be promising – same height as
last year – distance went from 828 to 1,056 feet. We ran out of room so we moved Merlin to Harry
Browns farm - 570 acres. Our testing went slowly. As we raised the carriage, the distances were not
what we predicted. We found a few things that needed fixing, but nothing dramatic. We are still looking
for fixes. New video >>>
Our best throw was at the WCPC -1589 feet
2007 Prep for Chunk
We have all the collapse and raising of the superstructure working great. It is very impressive. It's too
bad I can't show this at the chunk - we have too much post raising to do like setting up the support legs,
hanging the TA (throwing arm) and the carriage and connecting the two (TA and Carriage). We can set
up the machine in about 4 hours which includes leveling.
Our first throw was breath taking - it surpassed our wildest dreams. It went 750 feet.
1) Merlin is very quiet
2) Smooth throw
3) Great trajectory
4) Good whip at the end
5) Trailer hardly moved
This design has never been done - so we are forging new ground. In our testing - we found binding
going on when raising the carriage. We still don't understand the source of this binding. Also we found
with the UHMW that we are using as a bearing surface on the boggies that run on the J trace and the
Carriage on the Tower has more drag than we anticipated. We intend to change these to rollers.
To give you all an impression of the type of people you run into at the chunk - I was overcome by the
help and assistance we received from our friends and competitors. The folks from Fibonacci and from
"Feets don't fail me now" gave us sample of wheels we should consider. Yankee Siege and Pumpkin
Hammer teams both offered advice and assistance. All I can say is WOW........ We broke our machine
on the second throw - Bill Sharp, the Safety Officer from the chunk, was on the task and got us an expert
welder to help out. Again - WOW...... This is very cool. There are some very smart people at this chunk
and I certainly appreciate their help.
All in all - everyone seemed to like Merlin. It is unique. The design started with changes I wanted to
make on the FAT type Trebuchet - after 80 or so versions - it became Merlin. Jim Riley from Pumpkin
Hammer (one of the great guys) reminded me that we talked about the design of Merlin 5 years ago. I
looked at my old files and darned if he wasn't right on. The functional spec was completed in late 2004
and the first AutoCAD drawings was in 2005 - so the Merlin build has taken us 3 years.
In 2004 and 2005 – Yankee Siege was the world Champ – King Arthur came in third behind Pumpkin
This will not do.
I had a choice to make. Either make King Arthur bigger or come up with a new design. The safe route
was to enhance King Arthur. It has known qualities and we understand the design. But, the interesting
path is to energize the creative juices and go for a new design.
Well, you know what I did. Pulled out the modeling tool and spent hours and hours trying new plans
and strategies. After hundreds of designs, I finally came up with a winner. Unlike King Arthur, the team
needed some significant engineering help. This machine is a lot bigger, and the forces are
proportionately bigger. We found help in the “Man Killer” team. These guys are a lot of fun, and they
are engineers. We have known them since 2000. After the King Arthur team met with them in
Philadelphia, they became hooked. We finalized the functional design , and named the machine
Merlin. Read the details of how we developed the functional spec -> Merlin Design Process
2006 - Mid summer
We have completed the functional design phase of Merlin. We are in the midst of completing the stress
analysis. We will then complete the detailed design and build a parts list. Then we can start
construction of the truck (the device that holds the CW, the boggies, and the TA) and the tracks. We
have a 30 foot reinforced trailer built with a power plant, a hydraulic pump, stabilization bars and
hydraulic cylinders. So the infrastructure is completed. One of the design points of Merlin is the
machine is to be able to be run by two people.
We have been working on Merlin. Today we got the machine fully set up and erected. It took my breath
away. All I could think of was "What have I done now"?
Next - we need to finish work on the supports and the carriage - then we will be throwing.
Merlin infrastructure - Generator, Hydrulic
Pump, support structure and first cylinders.
And it works! (so far)
Added an video clip that shows Merlin transforming from traveling position to firing position. It's sped
up a bit to make the file size a lot smaller - but you'll get the point. The first time we raised it and I
looked up - all I could think was "OMG - what have I done now.............."
|What a show - when a pumpkin hits the cross bar on