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  #31  
Old 12-16-2008, 03:31 PM
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Mark II Mark II is offline
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The instructions for the Estes K-51 Sandhawk are available here at JimZ's website. Click on the little gray botton just above the launch pad to see a full PDF of the plans.

When was that liftoff photo taken, Dave? I love seeing that rocket fly (that's why I'm building one - and if I get through this build, it won't be my last Sandhawk). The Estes Sandhawk came out at just about the time that I was putting away my rockets "for a little while" . If I had only known...

Music wire would have been the stuff to use for the antennae (as they are for every scale size of this model). For the 1/10 scale Estes version, you would have needed 0.030" music wire (or 1 mm would have been close enough). You would need to come up with a way to securely anchor them to something inside the tube, such as a bulkhead; you wouldn't want to surface mount them. Mine will use 0.052". I am not concerned about them breaking off in flight, but rather in transport, so I am working out a mounting scheme that would allow me to screw them onto the rocket for flight, and then remove them for transport.

BTW, in some photos of the Sandhawk, such as one or two at Silverleaf's site, you can see little red balls (I call them "berries") attached to the ends of the antennae. These were put on to protect the antennae (and the launch personnel) during preparation for the launch, and then removed when they were ready to send it up. I may actually get some styrofoam or foam rubber balls and color them red to put on my model when I take it out to the pad. They would be just as functional for me as the originals were for the real launch crew!

Mark \\.
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  #32  
Old 12-16-2008, 04:51 PM
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Quote:
Originally Posted by Mark II
When was that liftoff photo taken, Dave? I love seeing that rocket fly (that's why I'm building one - and if I get through this build, it won't be my last Sandhawk). The Estes Sandhawk came out at just about the time that I was putting away my rockets "for a little while" . If I had only known...


That pic was taken Jan 2004 -- I was still using film then!

Quote:

Music wire would have been the stuff to use for the antennae (as they are for every scale size of this model). For the 1/10 scale Estes version, you would have needed 0.030" music wire (or 1 mm would have been close enough). You would need to come up with a way to securely anchor them to something inside the tube, such as a bulkhead; you wouldn't want to surface mount them. Mine will use 0.052". I am not concerned about them breaking off in flight, but rather in transport, so I am working out a mounting scheme that would allow me to screw them onto the rocket for flight, and then remove them for transport.

Mark \\.


Yeah, like I said I was lazy hence my remark I didn't do the model justice. One of these days I am going to build that 2nd one, and do it right (w/ music wire)
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  #33  
Old 12-16-2008, 06:45 PM
jetlag jetlag is offline
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Quote:
Originally Posted by rocketguy101
That pic was taken Jan 2004 -- I was still using film then!



Yeah, like I said I was lazy hence my remark I didn't do the model justice. One of these days I am going to build that 2nd one, and do it right (w/ music wire)



The Sandhawk is indeed a favorite.
When I built my Estes version (rebuilt-it is old, after all), for my mount for the antennae, I just built up the area with some fiberglass and basswood inside the plastic payload section right where the antennae would stick through to give it thickness, probably between 1/16 and 1/8 inch in a thin 'belt' inside. Then I used an index card cut at the proper angle to drill the 6 holes for the wires. I used epoxy to secure them (you can even bend the end that sticks through at a rt. angle to keep it from ever falling out). I cut and bent the wires according to the Estes patterns (three sizes). Works extremely well; only problem is if and when you bend one, when you bend it back some paint may flake off. Of course, that is easily fixable.
You could use little squares of carbon fiber, also; quite strong.
Allen

Honey, where is that d--- camera?!!!
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  #34  
Old 12-16-2008, 09:36 PM
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Quote:
Originally Posted by jetlag
The Sandhawk is indeed a favorite.
When I built my Estes version (rebuilt-it is old, after all), for my mount for the antennae, I just built up the area with some fiberglass and basswood inside the plastic payload section right where the antennae would stick through to give it thickness, probably between 1/16 and 1/8 inch in a thin 'belt' inside. Then I used an index card cut at the proper angle to drill the 6 holes for the wires. I used epoxy to secure them (you can even bend the end that sticks through at a rt. angle to keep it from ever falling out). I cut and bent the wires according to the Estes patterns (three sizes). Works extremely well; only problem is if and when you bend one, when you bend it back some paint may flake off. Of course, that is easily fixable.
You could use little squares of carbon fiber, also; quite strong.
Allen

Honey, where is that d--- camera?!!!

I have never seen the Estes kit "in the wild", either built or still in the bag, so I don't know if this would work. I was thinking that the builder could use a balsa bulkhead, cut in two (upper and lower halves), or two thick pieces of basswood, that would be held together with a small bolt and blind nut or threaded insert (something in 4-40, for example) through the center. On each of the two surfaces that meet when the two halves are bolted together would be a layer of thin foam sheeting. (You would only need, and would only want, the thin stuff. You can get it at craft stores.) The two halves would meet at the level of the antennas' entry holes. One of the halves (probably the bottom one) would be glued in, and the other would be able to come loose when the central bolt is loosened. You would construct the antennas with long "stems" (the part that is inserted into the model) that almost meet at the bolt in the center of the bulkhead. You would insert the stems into the airframe, sandwich them between the two halves of the bulkhead, and tighten down the bolt. If you subsequently bent an antenna and wanted to replace it, or if you wanted to remove all of the antennas for transport or shipping, you would just loosen the bulkhead bolt and pull one or all of them out. Does that sound like something that would work?

Mark \\.
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  #35  
Old 12-16-2008, 09:45 PM
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Quote:
Originally Posted by Mark II
I have never seen the Estes kit "in the wild", either built or still in the bag, so I don't know if this would work. I was thinking that the builder could use a balsa bulkhead, cut in two (upper and lower halves), or two thick pieces of basswood, that would be held together with a small bolt and blind nut or threaded insert (something in 4-40, for example) through the center. On each of the two surfaces that meet when the two halves are bolted together would be a layer of thin foam sheeting. (You would only need, and would only want, the thin stuff. You can get it at craft stores.) The two halves would meet at the level of the antennas' entry holes. One of the halves (probably the bottom one) would be glued in, and the other would be able to come loose when the central bolt is loosened. You would construct the antennas with long "stems" (the part that is inserted into the model) that almost meet at the bolt in the center of the bulkhead. You would insert the stems into the airframe, sandwich them between the two halves of the bulkhead, and tighten down the bolt. If you subsequently bent an antenna and wanted to replace it, or if you wanted to remove all of the antennas for transport or shipping, you would just loosen the bulkhead bolt and pull one or all of them out. Does that sound like something that would work?

Mark \\.


I know for my FSI 1/8 scale Black Brant - II, there's a nice, sturdy balsa bulkhead in the
payload body tube (just below the nose cone) that helps secure the wire antennas securely.
I drilled a pinhead size hole at each location and then used CA squirted into the hole before
I inserted the antenna. In each of the flights were there was a successful recovery, the
wire antennas were in excellent shape (can't say that about the second flight - see my
EMRR OOP product review for details ).
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  #36  
Old 12-19-2008, 04:12 AM
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As I continue on with the CAD model of the Sandhawk, I have hit a snag with the launch lugs. The drawings in the NARTS Scale Pak have left out some dimensions on the front lug, and there is a duplicate of a dimension on the rear lug that confuses me. Also, I don't see where these lugs are placed on the rocket in relation to the antennas. The end-on views showing the antennas don't show the lugs, or the split in the fin shroud -- at least it isn't clear to me.

Anybody have better details of these items?

BTW I have posted my illustrations and a higher resolultion version of the brochure on the Yahoo Scaleroc group.
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  #37  
Old 12-23-2008, 10:19 AM
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OK, to sorta bring this thread back full circle, I used the FS 31302 color from the NARTS ScalePak, looked it up on this website http://www.fed-std-595.com/FS-595-Paint-Spec.html and came up with the color hex code of D32200.

I then found this converter http://www.321webmaster.com/hex-to-rgb.php to get the RGB color of R 211; G 34; B 0 and used that in SolidWorks on my Sandhawk model. The attached are where I am at now.

As stated above, I need a couple dimensions that are missing in the NARTS documentation to finish out the launch lugs. I have made some guesses, along with the location of the antennas from the front edge of the antenna section and fin shroud. I have posted a pdf of my drawing along with the SolidWorks model on the scaleroc group for those interested.

If anybody has the details I am missing, I will update the model and drawing.
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