JAL3
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- Jan 17, 2009
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I need some help.
I signed up for a contest to be held in March by DARS, the Dallas rocket club. It will be my first contest aside from the informal "make it up as you go along" afairs my club sometimes has.
I already have my C egglofter built. I will be using George Gassaway's 2 minute egg plan. It has flown once in an eggloft competition my club held. The high winds did not help and I am glad the egg was in a balloon!
For the C Rocket glider, I have chosen the XP-2c plan on the NAR site. It was designed by Al Nienast. From what I have read, it will probably not be all that competitive in this day and age but I am intrigued by the swing wings and want to give it a try. I tried rounding up some of the material I did not have at the LHS today but I have some questions about the design I do not understand. I am hoping y'all will clue me in.
I have attached the PDF so you can see what I refer to.
1. Span: the plan says 30". I assume that is from wingtip to wingtip. Is it measured along the actual wing or is it the flat projection of th dihedral angle?
2. It says: "each wing swivels on a balsa axel sandwiched between two 1/16" balsa wing brackets." On the next page, the brackets are shown to be 1/8". WHich is correct?
3. The launch lug is sandwiched between the boom and and separator strut. The instructions say "5.32" I.D. alum. tube" That sounds like I could make this an L3 project by shoving a 98mm casing in the launch lug! I bought some alum. tubing that would fit over a 1/8" rod. Is that OK or am I missing something?
4. The rear "horizontal" stabilizers are shown at the bottom of page 1. What does the vertical line between "1/2 stabilizer" and "- 1/16" balsa" represent? does the tail have a dihedral also?
5. What is meant by (airfoiled on bottom)? That text appear just below the text mentioned in 4
6. Does this thing have a vertical stab.? Wouldn't it need something in that axis? If so, is it just a copy of the horizontal?
7. page 2 indicates that the pivots are TT5. Is that just another way of saying BT5?
8. Is a TT5/TT20 adapter ring the same as a centering ring for BT5 tube in a BT20 airframe?
I am not going to be disappointed if I do not win or place. I just want to take part and do the best I can. Can you offer any help?
View attachment xp-2c.pdf
I signed up for a contest to be held in March by DARS, the Dallas rocket club. It will be my first contest aside from the informal "make it up as you go along" afairs my club sometimes has.
I already have my C egglofter built. I will be using George Gassaway's 2 minute egg plan. It has flown once in an eggloft competition my club held. The high winds did not help and I am glad the egg was in a balloon!
For the C Rocket glider, I have chosen the XP-2c plan on the NAR site. It was designed by Al Nienast. From what I have read, it will probably not be all that competitive in this day and age but I am intrigued by the swing wings and want to give it a try. I tried rounding up some of the material I did not have at the LHS today but I have some questions about the design I do not understand. I am hoping y'all will clue me in.
I have attached the PDF so you can see what I refer to.
1. Span: the plan says 30". I assume that is from wingtip to wingtip. Is it measured along the actual wing or is it the flat projection of th dihedral angle?
2. It says: "each wing swivels on a balsa axel sandwiched between two 1/16" balsa wing brackets." On the next page, the brackets are shown to be 1/8". WHich is correct?
3. The launch lug is sandwiched between the boom and and separator strut. The instructions say "5.32" I.D. alum. tube" That sounds like I could make this an L3 project by shoving a 98mm casing in the launch lug! I bought some alum. tubing that would fit over a 1/8" rod. Is that OK or am I missing something?
4. The rear "horizontal" stabilizers are shown at the bottom of page 1. What does the vertical line between "1/2 stabilizer" and "- 1/16" balsa" represent? does the tail have a dihedral also?
5. What is meant by (airfoiled on bottom)? That text appear just below the text mentioned in 4
6. Does this thing have a vertical stab.? Wouldn't it need something in that axis? If so, is it just a copy of the horizontal?
7. page 2 indicates that the pivots are TT5. Is that just another way of saying BT5?
8. Is a TT5/TT20 adapter ring the same as a centering ring for BT5 tube in a BT20 airframe?
I am not going to be disappointed if I do not win or place. I just want to take part and do the best I can. Can you offer any help?
View attachment xp-2c.pdf