Boomilever for 2013

[LKN]

(If there is a 1/4 inch cross section rule)

For boom all members need to meet the 1/4 inch cross section requirement. I understand the base is excluded from the 1/4 inch cross section limit, but what about gussets? Aia's booms have a distal end connection that looks larger than just 1/4 inch, and I don't see how it is feasible for the critical connections if you are limited to a quarter inch.

[Aia]

(If there is a 1/4 inch cross section rule)

For boom all members need to meet the 1/4 inch cross section requirement. I understand the base is excluded from the 1/4 inch cross section limit, but what about gussets? Aia's booms have a distal end connection that looks larger than just 1/4 inch, and I don't see how it is feasible for the critical connections if you are limited to a quarter inch.

Actually, I never used wood that was wider than 1/4". If you go to my guide under "Distal End", you'll see a pretty good picture of my gusset. I used 1/4" by 1/16" balsa (if I recall correctly, it's been awhile), laminated over the top of the connection, and sanded down the excess wood. At that point, the wood was definitely just a hair below 1/4" wide. The angle between the compression and the tension is small enough that the 1/4" by 1/16" balsa covered the connection perfectly well.

Admittedly, the diagram in that section of the guide is not the best-- my paint skills made the lamination look larger and more square than it actually was.

[retired1]

Ala, Did you use any particular height on the bass triangles that you CA glued to the tension member at the base.
Was this your idea or was it borrowed? I have been looking for a method to "pin" the member to the base. This certainly does that.

[Aia]

Ala, Did you use any particular height on the bass triangles that you CA glued to the tension member at the base.
Was this your idea or was it borrowed? I have been looking for a method to "pin" the member to the base. This certainly does that.

I believe those triangles were cut from 3/32" square bass. I determined how long I wanted the triangle, and then used my exactoknife to cut along the would-be hypotenuse. If you do it correctly, you should end up with two near identical triangles. I usually cut out 8 or so triangles, picked the best four, and moved on from there. I did not ever experiment with a different size for those triangles, so there may be a better height choice out there.

This idea is mostly my own. I watched my predecessor in the boomilever event try many different types of bases in 2007. When it was my turn in 2008 to build, I knew which ideas were and weren't working for him. I then redesigned the base, improved it as I went along, and eventually arrived at what you see on my guide.

[_HenryHscioly_]

is there another way to cut wood into sticks from sheets other than using straight edge + razor blade?
My problem is that I often end up cutting in at an angle.

I want to buy sheets instead of sticks this year since it is cheaper, easier to view the grain, and easier examine the wood density across a sheet of wood than examining a bunch of sticks, but I dont think it's worth it if I cant cut properly.
I'm actually okay with cutting thin balsa(1/16" or 1/32"), but any thicker balsa sheets or any bass sheets, I always mess up.

[retired1]

Lots of people cut their own sticks last year for towers. I would not try to slit 1/4 balsa sheet. It is not that much more expensive to buy those as sticks. If you are at a hobby shop, you can be picky if they have any quantity of balsa.
A Harlan Slitter is a very good one. There is another one, I think it is a Johnson. You can find info on this at A2Z. Xacto used to sell one that used #11 blades. I do not find them sharp enough to do a good job. They have not changed this in 50 years. For a home built one, google " Curt Stevens Old Fashioned Rubber Stripper. You might be able to modify this to something useable.

When I used a metal ruler and any blade, I normally got it off angle near the fingers holding the ruler and got a parallelogram vs a rectangle. I have great days and poor days with my Harlan.

I really like American Line "Extra Keen Single Edge Blades" They are sharp! A box of 100 is not all that bad priced for superior blades, especially if you or your school are going to compete for more than one year. Take a look at tailspin models or aviation or something like that.

[iwonder]

Just to clarify...

Ray Harlan sells a balsa stripper on his website(something like indoor specialties), almost anything I've seen by him is very good quality, but I've never had the cash to buy it... (carbide anvils don't come cheap )

A2Z sells a couple different models, one of them is a Jim jones stripper that's cnc machined aluminium with laser etched plastic guides. All in all, a nice balsa stripper like that runs in the $60-$70 range, you're honestly probably better off continuing to do it by hand.

With the blades, when you strip thicker pieces, do it in multiple passes, that way you don't crush the wood as much, just be very careful about repeatition, you have to cut the same line every time. With this method most people use normal xacto blades just fine, just make sure you take care of them, etc, and you will have to change blades more often in this configuration.

I know it's all pretty basic stuff up there... I don't mean to insult anyone's intelligence. As a note I'll probably edit this whole thing up in 5 or so hours(to remove anything stupid) because I just got off a plane and it's 3 am over here... My brain is almost dead :/

[illusionist]

Actually, I've gotten my balsa stripper for about $8 if I can remember correctly. It's definitely not as high quality as some of the others, but it certainly gets the job done. I'll try to look up the website and post it here.

Edit: Here's a link to Amazon with the product. It's called the Master Airscrew balsa stripper. Great little tool, comes with a warranty too (which is useful, as the plastic threads do tend to wear out over time). http://goo.gl/YkL4v

[_HenryHscioly_]

http://www.hippocketaeronautics.com/hpa ... pic=5658.0
The 6th post has a simple way to strip sticks of wood.
I am going to try this method :], except I dont have blocks of wood...yet

[retired1]

Henry sent me this site. Lots of options. I copied the whole thing for a permanent reference. I like Olbill's. It is a poor mans Harlan. Chose the bottom wood carefully as the Fir on my Harlan would send the blade off with the very hard grain. When the blade was set to just barely go below the surface of the cutting board, the problem mostly went away. The test is to move the blade block block side ways. If it hangs up or scratches too loud, it is too deep.