Welcome to Boomtown!

aLAcrity Boomerangs is a group of boomerang enthusiasts from Los Angeles. At the moment, it is comprised of three people: Manny (a.k.a. v12aero), phnxhawk and Charles (a.k.a. hey_kuya).

Manny and I (phnxhawk) started this blog to share our interest in boomerangs--throwing and tuning, making our own rangs, as well as unraveling the science behind them. As we continue our journey into the world of boomerangs, we hope to make new friends and to expand our horizons. In this blog, we will post such things as videos from our regular throwing sessions, musings and lessons learned from throwing, and thoughts on making our own rangs.

Manny and I started throwing boomerangs since Spring 2009. It has been a long road as we developed a semblance of technique for throwing 'rangs. Nevertheless, after many a bruised hand or windy day, our fascination with these returning throwing sticks remains undimmed. We most certainly have more to learn about boomerangs, but we'll keep at it as long as we continue to have many happy returns.


Sunday, February 3, 2013

Carver's Corner #3 - Five by Five

Long looked-for, I'm sure: behold, my post about the boomerangs I carved during my brief escape from the work place in December.  By the by...I expect that my situation on the work front will persist well into 2013, but I'll post commentary, pictures and video when I can.

The Boomerangs

Anyway, as it turns out, carving boomerangs is becoming one of those activities in which I indulge whenever I take a few days off from work.  So, how could I resist carving a few more during the winter shutdown?

After the last run, I had it in mind to make a second Diabolino (in particular, one that is a little closer to the 2010 model that Manny has) replica using the smaller, 5/16 in diameter brass weights in lieu of the 1/2 in diameter ones.

Manny also put in a request for a replica of his Tiger by Roger Perry.  As he has expressed in the past, he is not especially fond of the feel of the Tiger in hand.  I liken it to my distaste for certain kinds of golf grips.  Certainly, they're functional, but the feel in hand just bugs me.  I bumped it to the top of the queue to make this a holiday gift for him, as well.

In addition to those two, I opted to make replicas of three other models: Bellen, Kilimanjaro and Cryderman Small Hook.  Since the Bellen model was apparently used as a juggling pair, I've always wanted to have a matched pair of my own.  With that type so difficult to track down these days, I decided to simply make a pair for myself.

The choice to make a couple hook type boomerangs was motivated, in part, to see what challenges the hook planform might provide.  I wanted to have two hooks on hand to see if any problems encountered with one were unique to the way I made it or were more characteristic of the type.  I was also curious to see whether the way I create the airfoils would help the Kilimanjaro retain enough spin to make it easier to coax a return during low wind conditions.  My previous creations seemed to have good spin retention, almost to the point at which I have been considering applying some form of standard, modular drag device to my future boomerangs.

In addition, Manny acquired a double weighted Cryderman Small Hook a couple years back, and he finds it to be challenging to throw and obtain the circular flight pattern he loves so much.  (This was during his "I want everything extra weighted for more distance and power" phase.)  This was yet another good opportunity to make a replica of a boomerang that had, in the past, challenged us.

So, there you have it.  Five boomerangs made in three days.

New Tools

After my previous experience cutting holes for weights by eyeballing circular shapes while using the Dremel rotary tool, I decided to acquire a cheap power drill.  Aside from these RC aircraft and boomerang projects, I don't currently have much other use around the house for a power drill.  Accordingly, I was keen on balancing performance and cost to obtain what would be a good "value" for me at this time.  I opted to pick up this Ryobi 12V cordless drill from my local hardware store for $50.  (Without getting into a discussion about the merits of shopping around for better prices,) I found this to be a good compromise choice.  It does the job pretty well, and I found that the holes I cut during this go 'round were much cleaner and a better fit for the weights.

I also added a couple sanding sponges like this one to my array of tools.  I picked up a couple different grits, 60 and 100, to try out.  Charles suggested this type of sanding tool to help me smooth out some of the contour lines on the boomerangs.  Overall, I'd say I like it, especially when I am working over a broad, curved surface or when I start moving into the finishing sanding.  In particular, I like that they are easier and lighter to grip for long periods, but I still prefer to use my sanding block for removing material by hand.

The Result

I'm reasonably pleased with how the boomerangs turned out.  Everything worked like a charm.  Since I was not rushing the work (compared to the last set, anyway), the airfoiling work turned out better (I think) or at least more consistent.

This run of boomerangs was also the first for which I did not create contour maps from crude CAD models.  I simply did not have enough time to do this for all the boomerangs in the time allotted.  However, I had an idea of how they would look based on how I usually model the surfaces.

The pictures of the finished boomerangs are here, but the following are the main ones to give you the overview:

From Carver's Corner #3

From Carver's Corner #3

From Carver's Corner #3

From Carver's Corner #3

From Carver's Corner #3

Verification and Acceptance Testing

I had a chance to take the boomerangs out for a spin a few days before Christmas.  Overall, I encountered no show-stoppers with the flight tests.  I had a chance to capture some video before my batteries cut out that first day of testing.

The Diabolino, Tiger and Bellens flew pretty decently "out of the box," so to speak.  Although I did add some tuning tweaks to them, they were nothing major.

The "lighter" Diabolino matches the weight of the 2010 model pretty closely and is some 20 grams lighter than the first replica I carved.  So, a hard throw and a stiff breeze are not required to achieve a nice flight and return with the new version.  I also noticed, while out testing, that I dropped the brass weight into the wrong hole on the trailing arm.  Although it's cosmetically annoying, I have not noticed any significant negative impact on the way it flies.

The two Bellens will need some additional attention to improve them as a matched pair, but they fly pretty similarly as is. The Tiger, meanwhile, attained Manny's seal of approval in a subsequent throwing session.  Comparing the two, the Finnish birch version feels more "solid," but thanks to my airfoiling, it does not drop quite as quickly on the return, as compared to the original.

The hooks were a little more problematic.  I found with both of them that they tended to roll "shut" very quickly, transitioning to a more vertical attitude after release and knifing into the ground on the way toward the apex of the turn.  I countered this with a healthy amount of dihedral, after which the hooks would tend to stay airborne, but not necessarily in a pretty way, dipping toward the ground past the apex, but climbing slightly toward the end of the flight.

The hooks also needed to be thrown a fair amount off-wind compared to my other boomerangs. This is a problem I have yet to solve, although I wonder whether it may only be an issue of some twisting of the wings, which the boomerangs, probably owing to how they were oriented on the plywood sheet when I cut them, tend to resist.  These issues were particularly pronounced in the Cryderman hook replica. 

Well, that's all for which I have time today, folks.  Look forward to some future updates so that you may keep up with what we've been throwing during the winter season!

"Putting my spin on boomerangs..."