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Author Topic: What balsa for different bits?  (Read 2007 times)

Offline Electric George

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What balsa for different bits?
« on: April 05, 2022, 02:35:40 AM »
I found the balsa density calculator which is great. I have weighed my balsa and know what density it is. Now I need to know is there some rule of thumb for what density for different bits.
Example: Model shop sent me a 1/2" sheet that is nearly 13lb density. is this too heavy for a 35 size profile fuselage? What density range for solid tail feathers on this size? What density for ribs? So real control line beginners balsa selection stuff.
Done a few searches on here and tried google but not found what I was looking for.

Any thoughts or links to where I can find out this stuff would be greatly appreciated.

Many thanks.

Online Craig Beswick

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Re: What balsa for different bits?
« Reply #1 on: April 05, 2022, 03:18:06 AM »
George,
you are looking for the best and lightest balsa you can get!

The best guys are looking for, "Contest Balsa", which is 4lb- 6lb. They, I guess, would prefer it to be under 5lb!

I am fortunate that contest balsa is still available here in Australia.

Good luck.
Craig
Ps. 13lb is probably too heavy for your fuselage. There are other ways of stiffening a profile fuselage than heavy wood.
AUS 87123
"The Ninja"

Offline Electric George

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Re: What balsa for different bits?
« Reply #2 on: April 06, 2022, 01:41:07 AM »
Thanks for the replies,
Craig - yes, that makes sense and is a good rule of thumb. No Contest balsa here but, when the opportunity presents itself, I can carefully select the best available balsa.

Ty- I was surprised at just how heavy that sheet of wood felt in my hand! This is what got me thinking, I have already consigned the sheet to the 'other things wood pile' and have already thought of a couple of uses so at least it will not be straight to the bin; thankfully it was purchased just before the rising balsa prices so not too painful on the wallet!

Online Dan McEntee

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Re: What balsa for different bits?
« Reply #3 on: April 06, 2022, 08:58:19 AM »
I found the balsa density calculator which is great. I have weighed my balsa and know what density it is. Now I need to know is there some rule of thumb for what density for different bits.
Example: Model shop sent me a 1/2" sheet that is nearly 13lb density. is this too heavy for a 35 size profile fuselage? What density range for solid tail feathers on this size? What density for ribs? So real control line beginners balsa selection stuff.
Done a few searches on here and tried google but not found what I was looking for.

Any thoughts or links to where I can find out this stuff would be greatly appreciated.

Many thanks.

    I don't think that 13 pounds is completely unusable in 1/2" thickness. For a profile fuselage, a lot of that is going to be cut away when you cut the outline and then shape it. There are some designs out there that have a minimum side area like the Excalibur and Trophy Trainer and that stiffer wood may just be the ticket for those models. You have to look at the big picture for the model you want and for the parts for that model. The fuselage for some profile models can even be composite construction, where you use that 13 pound wood for the nose section and then build on an open structure for the tail end, and you can get several nose sections out of a 36" sheet. Read and re-read Mr. Hunt's post and follow the old saying, " If you make use of what you have got, then you won't need what you have not!"
   Type at you later,
    Dan McEntee
AMA 28784
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AMA 480405 (American Motorcyclist Association)

Online Ken Culbertson

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Re: What balsa for different bits?
« Reply #4 on: April 06, 2022, 09:18:15 AM »
Except for a couple of small orders, I have been building with "Hobby Lobby" grade balsa for a couple of years now.  When they get in a new shipment, I go through it and grab anything that looks reasonable.  Much of it turns out to be 6-8 lb and their recent stock has been pretty good. Fortunately for me, the other scavenger hunters are closer to other stores, so I usually get first pick.  Far cry from calling up MAL back in the day but what is - is.

I use 1/16 where I used to use 3/32 and cut out a lot more of non-critical balsa, hollow thinner, replace blocks with molded, etc.  My planes are coming out at 60-65 for a full size PA.  Not light but not heavy either.  The biggest savings however comes where most would question my sanity (some do that anyway).   The Finish.  For all but a handful of us those extra 4 or 5 points to go from a 14-15 to a 19-20 just aren't worth the weight.  I try, not always successfully,  to keep the workmanship clean but piling on the clear is just not going to happen anymore.  That is just me and I don't prescribe it for anyone else.

Ken
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If it is not broke you are not trying hard enough.
USAF 1968-1974 TAC

Offline Electric George

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Re: What balsa for different bits?
« Reply #5 on: April 07, 2022, 05:05:23 AM »
Thanks all for your replies.

There's some great information for me here to absorb into my growing knowledge.   


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