Re: [RCSE] 1/3 ASW-20 by Dream Catcher/Mark Smith Info Needed

[Lee Estingoy]

Frank,   Sounds like you are taking on a project that may be a bit beyond your experience.  No problem, just make sure you are getting good advice -- make sure that person has been there and done that.    When you move from the usual stuff, like TD or smaller sailplanes to larger scale ships, especially 1/3 scale, the forces involved and therefore the building techniques are different.   I have built several larger scale ships.  I've made a lot of mistakes for you.  I have articles here.   www.kcse.us, look under articles section....   To answer your question, no, regular US Obechi is not sufficient BY ITSELF as a skin for 1/3 wings IF the skin is your sole support for the wing.  If you build a foam core wing with a spar system, then YES, US thickness obechi will work IF you also use some glass or carbon fiber beneath it as part of your composite construction.   I have used, and recommend Avia sport pultruded carbon strips for the spar.  It is part of a box spar that has been discussed and detailed by Dr. Drela.  You can scale it up easily to your model's size using the Excel spreadsheet also availble at the site above.   Good luck,   any more questions, do not hesitate to contact me.   Lee ----- Original Message ----- From: George Voss To: 'Frank Deichsel' ; 'RCSE posting' Sent: Tuesday, December 27, 2005 12:10 PM Subject: RE: [RCSE] 1/3 ASW-20 by Dream Catcher/Mark Smith Info Needed Frank, I’m not familiar with this particular plane but I’d agree with you.  The obechi we get here in the US is going to be pretty thin on a 5M wing unless you have a substantial spar system.  Have you thought of using 2 layers of the thin obechi?   George   From: Frank Deichsel [mailto:[EMAIL PROTECTED] Sent: Monday, December 26, 2005 9:15 PM To: RCSE posting Subject: [RCSE] 1/3 ASW-20 by Dream Catcher/Mark Smith Info Needed   Hi,   I got a good deal on a 1/3 scale ASW-20 kit made by Mark Smith/Dream Catcher Hobby. Unfortunately there are no plans included and I need to know what thickness obechi the wing cores are cut for. I did some research but no success. The common thickness for sheeting seems to be 1/42 here, but from what I found that seems to be too thin for a 5 meter wing. There is a wing made by Mueller in Germany in the same size which is sheeted with 1.2 mm which is roughly twice as thick.   Any info would be appreciated!   Frank