peanut scale rules???? free body tubes


Well-Known Member
Jan 4, 2004
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Hi does anyone know the rules for peanut scale?
I'm lookin in Sport rocketry Nov/Dec 2003 issue and it says qoute
peanut scale requires that models be small either under 30cm tall,or under 2 cm in diameter.

Can I build a model that is 28mm's in diameter as long as the finished product is less than 300mm's ?

A tips for anyone needing free body tubes :D

I've found that the tubes from sanding discs from autobody shops are a perfect fit for a 24mm engine and strong in construction.
Just walk in to your local bodyshop and ask for tubes they have lots from masking paper to sand paper rolls:)


Micro Craftman/ClusterNut
TRF Supporter
Jan 18, 2009
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Washington DC
You are correct the rule is 30cm (300mm) in length, OR 2cm (20mm) in diameter. So yes you could build a model 28mm dia x 300mm long but you better be darn sure you are not 301mm long or the model will be DQ'ed. Personsally I always try to keep the model as small as practical for the detail I'm planning. I've also found it is helpful to stick with BT-20 (18mm) tubeing or smallers just to stay on the safe size. Also the 2cm dia. is for the main airframe like the payload section on the DeltaIII excluding the booster motor clusters, Shuttle models are a bit differrent, I think I heard last year that the ET was considered the "Main diameter" but don't quote me on that, If you have a specific prototype in mind drop Tom Lyon a message, he can make a determination on your specific request.
Hope this helps a little.