Search found 91 matches

by jma
April 11th, 2014, 2:47 am
Forum: 2014 Build Events
Topic: Boomilever B/C
Replies: 690
Views: 98238

Re: Boomilever B/C

chinesesushi wrote:Look back, I asked this exact question a while ago. It was suggested that the loading block's center should be above the point between the top and bottom.
Thanks :D
by jma
April 10th, 2014, 5:29 pm
Forum: 2014 Build Events
Topic: Boomilever B/C
Replies: 690
Views: 98238

Re: Boomilever B/C

For a tower crane boomilever, should I have the loading block (1.) align with where the tension members are connected to the compression members at the bottom of compression member or (2.) in between the two points where the tension arm connects with the top and bottom compression members? I tried b...
by jma
February 10th, 2014, 8:15 pm
Forum: 2014 Build Events
Topic: Boomilever B/C
Replies: 690
Views: 98238

Re: Boomilever B/C

Thanks, Iwonder. I usually apply the glue directly from the bottle. To keep the glue from drying before I reach the other end, I usually pour more glue than needed, so my beams are always heavy. But still sometimes I don't have enough time and I end up throwing away the pieces. So when I used the ap...
by jma
February 10th, 2014, 5:52 pm
Forum: 2014 Build Events
Topic: Boomilever B/C
Replies: 690
Views: 98238

Re: Boomilever B/C

Is there a strength difference between medium glue and ultra-thin glue? The boomilever that I built using ultra-thin glue failed at the compression members (the side wall of the box beam just peeled off) early in the testing. I used the glue applicator as instructed in Jander14indoor's post. I appli...
by jma
February 4th, 2014, 6:31 pm
Forum: 2014 Build Events
Topic: Boomilever B/C
Replies: 690
Views: 98238

Re: Boomilever B/C

Someone mentioned that their compression members are 3cm apart. How does the loading block stay on the compression members without interfering with the tension members?
by jma
January 6th, 2014, 6:48 pm
Forum: 2014 Build Events
Topic: Boomilever B/C
Replies: 690
Views: 98238

Re: Boomilever B/C

nxtscholar wrote:Ahh, tomorrow is my regions. :(

Any last minute advice on how I should transport the boom to ensure maximum safety, or anything else I should bring?
I would bring some extra wood, glue, I meant level (not balance), a ruler, goggles, and this year's rules. Good luck tomorrow.
by jma
January 6th, 2014, 2:59 pm
Forum: 2014 Build Events
Topic: Boomilever B/C
Replies: 690
Views: 98238

Re: Boomilever B/C

That's true for me, too. My retangular base keeps failing and it takes me way too long (2 to 3 hrs) to connect the T, C, and base together. I've decided to buy a 5/8" dowel. I contacted Specialized Balsa and since it's a special order, there'll be a $30 set up charge :o . Are there other place...
by jma
January 4th, 2014, 10:54 pm
Forum: 2014 Build Events
Topic: Boomilever B/C
Replies: 690
Views: 98238

Re: Boomilever B/C

It's crunch time in New Jersey. My regions is just 5 days away :( So jma, I built that rectangular compression beam using the 1/32 side panels and 1/20 for my top and bottom; it weighed 10.5 grams, rather heavy considering what you and I were going for. I had an efficiency of 700. Now, the actual c...
by jma
December 31st, 2013, 5:04 pm
Forum: 2014 Build Events
Topic: Boomilever B/C
Replies: 690
Views: 98238

Re: Boomilever B/C

jma, are you pretensioning your compression cross-bracings? If that's the case, then when the compression member is unloaded it'll bend. I'm not sure how to go about gluing the tension members onto a compression member like that, perhaps if you could glue the tension members on the compression memb...
by jma
December 31st, 2013, 4:47 pm
Forum: 2014 Build Events
Topic: Boomilever B/C
Replies: 690
Views: 98238

Re: Boomilever B/C

fanjiatian wrote:Can you give some more details on pulling the bracings? Does that help the glue connection? I'm having trouble visualizing it
I mean that I might have stretched the bracings too much when I glued them on. I just wanted to make sure the bracings were completely straightened out.

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