bBalsa Densityyb

[Sandy Wood]

An open question to everyone but I guess the electric gurus of nigel and tony.
As Balsa density is important Just what density should we be looking for?. My local model shop owner is very good and lets me go through his balsa stock using digital scales (yes i know its a bit anora...!!!)but trying to get the weights suggested by nigel hawes for his great designs is a real pain. Soo... what density are we looking for for soft balsa?
Ditto med balsa
Ditto hard balsa
I have found trying to select balsa by eye and feel dire.
Many thanks in advance
Sandy

[Adrian Jones]

Try these links:

http://pldaniels.com/flying/balsa/howtos/calculate-balsa-density/


http://www.pelaero.com.au/Density%20chart.htm

[Mike Rolls]

It's not at all 'anorak' - it's essential. You will fond that vaious people do tend to vary in their categorisation. FWIW mine is:
Light under 6 lbs cu/ft
Medium 6-10
Hard over 10, with small section high stressed items such as wing spars looking to 14-16.
Grain is also important - for spars and longerins make sure that the grain is as stright as possible. For rolled sheet decking, LE sheeting and the like flat sawn - bends easily across the grain - is a boon. For ribs and formers quarter sawn - has a sort of 'speckled' appearance to to - is best.

HTH

Mike

[Sandy Wood]

Hi Mike,
Thanks for the reply.
With luck I can get Balsa under 6 lbs cuft perhaps 1 in 10 sheets out of sheets already selected by eye.
Getting hard balsa is easy ie 9 out of 10.
What I very rarely see is the sort of Balsa which Nigel ALWAYS seems to have for his solid sheet wings ie the creamy white stuff which you just know weighs next to nothing!!!

[Sandy Wood]

Hi Adrian,
Thanks for the reply,
I use a balsa density spreadsheet which I wrote in Excel.
Pelaero balsa is available from Mike Woodhouse at Freeflight Supplies but he can only post 18" lengths aaargh!!
Cheers Sandy

[Mike Rolls]

Sandy
I know what you mean! I no longer have a model shop anywhere near (i.e. under 50 miles!) so I get my wood from Balsa Cabin who are very good at sending what you ask for, although they reckon soft as being up to around 7 lb.

Many people fail to realise just how variable balsa wood is, and how important careful selection is. I have had 1/32 wood at under 4 lb which was virtually as rigid as 1mm ply - lightest piece I had of that sort of weight was 3.2 lb - used for tail ribs for open rubber models. I've also had wood of around 4 lb which was about as structurally useful as marshmallow!
Mike

[Sandy Wood]

Hi Mike,
Thanks for the reply. It has been suggested that I use Balsa Cabin by the guys producing the replica Frog rubber powered models. Seeing the quality of the upper nose block material they supply and your recommendation seals it, I will give Balsa Cabin call.
Many thanks
Sandy
ps I am lucky because my local shop Wycombe Models do try very hard (and succeed) to provide an excellent service.

[Christopher John]

Hi Sandy, balsa cabin is a good suppier but you need to order a minimum of £25 worth of wood.

[Sandy Wood]

Hi Christopher,
Thanks for the reply. Balsa Cabin have been suggested by various people so I will give them a good try. Sad news that richard at Wycombe Models is closing down so I can no longer sneak down claiming that I am going to B&Q. Stike another one to the internet/chinese.