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Re: Building Materials, Excluding Covering
Posted: October 20th, 2011, 9:44 pm
by chalker
illusionist wrote:Lol. Hmm... would I get penalized for using an unethical material on my copter? =P
Nah.. go ahead and use all the blood diamonds, elephant ivory, whale blubber, exotic rainforest woods, mink fur, and child sweatshop fabric you want! I'm sure it'll result in a very high performance device;)
Re: Building Materials, Excluding Covering
Posted: October 21st, 2011, 5:51 am
by jander14indoor
Frogger4907 wrote:Mr. Anderson,
What would be your recommendations as far as bearings go? Any favorites? Certain ones better than others? etc.
edit: If you were doing this event and you had to choose a bearing which one and why?
Thanks.
Whatever I had on hand that was reasonably suitable. Not much magic in the bearings other than straight and low friction.
Hmmm, on hand I have home-made Al prop hangers similar to penny-plane bearings like this:
http://www.a2zcorp.us/store/ProductDeta ... uctID=4338 I'd probably use these as it is easy to change rotors and try different things.
I have the materials to make wire pigtail bearings. Like this:
http://www.indoorduration.com/INAVHobbyShopper3.htm But since I have the others handy, I probably wouldn't take the time.
To reduce friction I'd use brass or teflon washers like these:
http://www.a2zcorp.us/store/ProductDeta ... uctID=1202 I always put two on the prop wire between the rotor and the prop hanger.
The key is low friction, the rotor shouldn't hang up at all, and low weight.
Jeff Anderson
Livonia, MI
Re: Building Materials, Excluding Covering
Posted: October 21st, 2011, 6:36 am
by Frogger4907
Thank you sir! Your input is always appreciated!
Re: Building Materials, Excluding Covering
Posted: November 13th, 2011, 7:14 pm
by theandrew
Does anyone know of a material stronger but yet lighter than balsa? I've looked at carbon fiber, but I'm not convinced it's worth the time and energy. The reason I ask is for the new chinook style incentive. I have some designs, but keeping the weight low is a HUGE issue.
Thanks
Re: Building Materials, Excluding Covering
Posted: November 13th, 2011, 7:19 pm
by Frogger4907
theandrew wrote:Does anyone know of a material stronger but yet lighter than balsa? I've looked at carbon fiber, but I'm not convinced it's worth the time and energy. The reason I ask is for the new chinook style incentive. I have some designs, but keeping the weight low is a HUGE issue.
Thanks
I already made a Chinook style helicopter to 4.1 grams, a few tweaking and my scores could get ridiculous

Re: Building Materials, Excluding Covering
Posted: November 13th, 2011, 7:23 pm
by Lily Essence
I've been looking around as well (aluminum, plastics, carbon, kelvar, etc) and have found that things weigh alot more than balsa in terms of g/ft... Honestly, I don't think my helicopter would use the strength that carbon fiber offers; balsa's strength does just fine, and weighs less...
Am I looking at the wrong things, or not being specific enough? Is there a site or store that sells helicopter sized pieces of light weight material? I'll keep searching for something lighter and as strong as balsa, but any nod in the right direction would be appreciated!
Re: Building Materials, Excluding Covering
Posted: November 13th, 2011, 7:25 pm
by theandrew
Frogger4907 wrote:theandrew wrote:Does anyone know of a material stronger but yet lighter than balsa? I've looked at carbon fiber, but I'm not convinced it's worth the time and energy. The reason I ask is for the new chinook style incentive. I have some designs, but keeping the weight low is a HUGE issue.
Thanks
I already made a Chinook style helicopter to 4.1 grams, a few tweaking and my scores could get ridiculous

Out of balsa? You didn't fly it at Southland, did you?
Re: Building Materials, Excluding Covering
Posted: November 13th, 2011, 7:46 pm
by chalker7
theandrew wrote:Does anyone know of a material stronger but yet lighter than balsa? I've looked at carbon fiber, but I'm not convinced it's worth the time and energy. The reason I ask is for the new chinook style incentive. I have some designs, but keeping the weight low is a HUGE issue.
Thanks
Balsa is really your best bet. Carbon fiber is actually very dense and it is difficult to use a small enough amount to get down to weight. However, the good news is that since balsa is a natural material there is a huge variability in the weight of different sheets and sticks. What I would recommend is to choose the lightest and stiffest balsa wood available while being very careful with your construction (wood dimensions, glue use, covering, etc) to get down to weight. Browse through some of the archived forums on this site for Helicopter and Wright Stuff (and even towers/bridges) for some more detailed descriptions of reducing weight (in particular, search through jander14indoor's posts)
Re: Building Materials, Excluding Covering
Posted: November 13th, 2011, 7:52 pm
by chalker7
Lily Essence wrote:I've been looking around as well (aluminum, plastics, carbon, kelvar, etc) and have found that things weigh alot more than balsa in terms of g/ft... Honestly, I don't think my helicopter would use the strength that carbon fiber offers; balsa's strength does just fine, and weighs less...
Am I looking at the wrong things, or not being specific enough? Is there a site or store that sells helicopter sized pieces of light weight material? I'll keep searching for something lighter and as strong as balsa, but any nod in the right direction would be appreciated!
Wood selection is really tough. You can get by at your normal hobby shop if you literally weigh every single stick/sheet before buying it, but this can be hit or miss and take quite awhile. You can buy preselected light balsa wood from places like lonestar balsa, but it is more expensive. Here's a link for their 4-6 lb/cubic foot stock (the light stuff) if you're interested.
http://www.lonestar-balsa.com/Ordering/Order.php?PROD=2&
A2Z corp also carries indoor grade wood, but that is even more expensive. Here's a link for them.
http://www.a2zcorp.us/store/Category.as ... ood+Indoor
Re: Building Materials, Excluding Covering
Posted: November 13th, 2011, 8:37 pm
by Lily Essence
chalker7 wrote:You can buy preselected light balsa wood from places like lonestar balsa, but it is more expensive. Here's a link for their 4-6 lb/cubic foot stock (the light stuff) if you're interested.
http://www.lonestar-balsa.com/Ordering/ ... hp?PROD=2&
I'm eyeing the wood there, and 4-6 lbs seems a lot better than the stuff I've been buying at my local hobby shop, but Lonestar requires orders of at least 25 dollars + 12.50 for shipping (And then 8.25% tax on that since I live in Texas).
Have you ordered from Lonestar before? Are they dependable and the wood accurate to its description? I don't want to fork over almost 40 dollars for wood that isn't what I was expecting. Thanks for the help!
EDIT: Also, what do they mean by "Grain selection is $.20 per sheet. Weight selection is an additional 25% of the cost of the sheet when available." (0.o) Does this mean I should add $0.20 to every sheet I'm ordering? or 25% since I'm looking at 4-6 lb wood? Confusing site... (=.=)
Second EDIT: What does AAA mean? I know what A(B,C) Grain is, but is AAA some sort of more specific way of saying "A Grain"?