Can someone post or send me the shroud equation from Tim Van Milligan's first "Design & Construction of Model Rockets"? It's the one with a green cover & one rocket blasting off. I own the book, but that page fell out. Thanks. -- Richard "my Team America kids need it" Hickok
will this work:
Wow, just looked at that mess and someone needs to take a refresher course in how to reduce algebraic equations.
I use, using the same nomenclature: R1=inner radius of shroud R2=outer radius of shroud H= length of shroud D2= large Diameter D1=small diameter P=angle between R1 and R2
R1=D1*H/(D2-D1) R2=R1+H P=180*D2/R2
Kooch
snipped-for-privacy@ix.netcom.com (Kevin Kuczek) wrote in news: snipped-for-privacy@posting.google.com:
Sorry, it ain't that simple.
len.
It's actually pretty easy t derive from scratch...
Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!
Take a look in the Handbook of Model Rocketry. I'm not sure which version because I don't have access to it right now but, there was a formula in there for making reducing cones and it worked well. It was also a whole lot simpler than that stinker listed in an earlier post.
since we're posting code now:
Private Sub ShroudCalc(Dia1 As Single, Dia2 As Single, Length As Single, Rad1 As Single, Rad2 As Single, Arc As Single, taper As Single) Dim SmallDia As Single, LargeDia As Single Dim D As Single, E As Single
If Dia1 = Dia2 Or Length = 0 Then Exit Sub
If Dia1 > Dia2 Then LargeDia = Dia1 SmallDia = Dia2 Else LargeDia = Dia2 SmallDia = Dia1 End If 'Despite their slightly different form, these three sets of equations give 'identical results for Rad1, Rad2, and Arc. The intermediate 'E' is 'different, but that makes no practical difference.
'Van Milligan ' D = (LargeDia - SmallDia) / 2 ' E = Sqr(Length ^ 2 + D ^ 2) ' Rad1 = E * SmallDia / (LargeDia - SmallDia) ' Rad2 = E * LargeDia / (LargeDia - SmallDia) ' Arc = 180 * LargeDia / Rad2 'degrees 'Stine Handbook of MR ' D = (LargeDia - SmallDia) / 2 ' E = 1 / Sqr((Length / D) ^ 2 + 1) ' Rad1 = SmallDia / (2 * E) ' Rad2 = LargeDia / (2 * E) ' Arc = 360 * E 'degrees
D = LargeDia - SmallDia E = Sqr(Length * Length + D * D / 2) Rad1 = E * SmallDia / D Rad2 = Rad1 + E Arc = PI * LargeDia / Rad2 'radians 'Arc = DegtoRad(Arc) 'convert Arc to radians (Stine or Milligan) taper = Atn(D / Length) * 180 / PI End Sub (__ (__ (_____ (______ TM (__ (__ (__ (__ (__ (__ (__ (__ (__ (__ (__ (__ (__ (__ (________ V1.64 (__ (__ (__ (__ (_____ (____ (__ (__ Freeware CP/CG Calculator (____ (______ (__ (c)1996 Gary A. Crowell Sr. snipped-for-privacy@cableone.net
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