Sandia Sandhawk - suggestions on the red/orange color

[blankjorge]

Hi Doc,
I'm working up a somewhat sport scale of a Sandia Sandhawk. As you know, the body is supposed to be painted in a red/orange color. Any guesses on a canned spraypaint that's close to the appropriate color? I don't have any compressor based spray paint or airbrush equipment.

The base kit is a Yank 3" Sandhawk. The tube is now glassed and I have modified the original to support dual deploy. The goal is to learn DD with this rocket, but I'd like the finish to look good for at least the first flight.

Thanks!

[Mark II]

Hi Doc,
I'm working up a somewhat sport scale of a Sandia Sandhawk. As you know, the body is supposed to be painted in a red/orange color. Any guesses on a canned spraypaint that's close to the appropriate color? I don't have any compressor based spray paint or airbrush equipment.

The base kit is a Yank 3" Sandhawk. The tube is now glassed and I have modified the original to support dual deploy. The goal is to learn DD with this rocket, but I'd like the finish to look good for at least the first flight.

Thanks!
Krylon Red-Orange Fluorescent paint. Or any other bright red-orange, for that matter.

As you may already know, there is no officially documented shade of red that was used on the rounds that were painted that color. The Sandhawks were all painted white at the factory, and I do recall seeing a photo somewhere on the web of a white Sandhawk mounted on its launcher. The engineers at the launch sites decided that all-white Sandhawks would be difficult to visually track, though. So, at least in the case of flight 281-3, the third single-stage flight, launched from Hawaii (which is the one that most builders try to model), either the scientists or the launch personnel went out and bought cans of spray paint and used them to paint the Sandhawk a bright color before its flight! The color was whatever shade of red that they could get their hands on. Since there have been slight color shifts in the prints and reproductions of the few photos that are available for that flight, the exact shade of red that was used has never been definitively established. In most photos, though, it appears to be a bright shade of red-orange. Krylon Red-Orange Fuorescent happens to be what I plan on using on the 2-inch sort-of-scale Sandhawk that I am building, when I finally get to the painting stage, but I make no pretense of claiming that this is the one-and-only "right" color. And I may switch it if, in the meantime, I see another version that I like better.

Some have suggested using Allis-Chalmers (a k a Persian) Orange, which is available as a spray paint from Rusto-Leum, but, to me, it looks too orange. It works fine on a scale Jayhawk, but not on a Sandhawk, at least to my eye. If you decide to go with the Krylon, be aware that they make two different shades of fluorescent red spray paint: Red-Orange, and another shade called Cerise Red. The Cerise contains no orange at all, and comes out looking just a couple of shades darker than hot pink, so I don't think that it would work at all on a Sandhawk. I haven't done a whole lot of research into what other red-oranges are available in spray cans, so if you find something else, let us know. I'll be interested in seeing what you use.

Mark \\.

[Mark II]

I just thought of another shade of red that I have used in other projects that might work for the Sandhawk - Duplicolor Radiant Fire (EDSCC382). It is automobile spray paint, and I bought it at Advanced Auto. It is absolutely one of the most fiery non-fluorescent reds that I have ever seen come out of a spray can.

Mark \\.

[blankjorge]

Goodness, thanks for the details. I had done some "google" research on the Sandhawk but clearly never scratch the surface....thanks!

I'm going with the Duplicolor Radient Fire because I have encountered an interesting "fading" issue with the Krylon paint. In direct sunlight, I experience a situation where the Krylon dayglow took on the shadows of objects held above the paint. I might have been the particular bottle I used, but biased towards Duplicolor because of it's ease of use.

Thanks again for your information and suggestions. If I can figure out how to post pictures, I'll include a picture once the building is done...and before I lawndart the poor beastie.

[Mark II]

Here's (http://scale-rocketry.tripod.com/id4.htm) a good site for data (photos) for the Sandhawk.

Also, I got a truly amazing amount of information (including the background info I posted before) from the NARTS (https://blastzone.com/nar/narts/store.asp?groupid=92400111757284) Sandhawk Scale Pack, written by Matt Steele and Craig Beyers.

Mark \\.

[rocketguy101]

Here's (http://scale-rocketry.tripod.com/id4.htm) a good site for data (photos) for the Sandhawk.

Also, I got a truly amazing amount of information (including the background info I posted before) from the NARTS (https://blastzone.com/nar/narts/store.asp?groupid=92400111757284) Sandhawk Scale Pack, written by Matt Steele and Craig Beyers.

Mark \\.

I scanned a photo I got from Thiokol back in the 70s which is the same as one of the photos from the site you listed. My photo doesn't appear to have the color-shift. Here is the link
http://www.geocities.com/rocketguy_101/images/sandhawk.JPG

edit: if that direct link won't work try going to my photo page (http://www.geocities.com/rocketguy_101/strib_rocpic_4.html) and get the hi-res from there.

[blankjorge]

Thank you for the photo. The color is great....but the placement of the screws on the fins and aft section is priceless! The color on the payload section matches duplicolor anodized green. I'm cook'in with gas!
What I like best about rocketry -- the people

[Royatl]

I scanned a photo I got from Thiokol back in the 70s which is the same as one of the photos from the site you listed. My photo doesn't appear to have the color-shift. Here is the link
http://www.geocities.com/rocketguy_101/images/sandhawk.JPG

edit: if that direct link won't work try going to my photo page (http://www.geocities.com/rocketguy_101/strib_rocpic_4.html) and get the hi-res from there.


However, remember that color photo emulsions can not accurately record a flourescent paint, simply because 1) they aren't sensitive to the UV range, and 2) the dyes in a print or slide are not meant to accurately reproduce a flourescent or iridescent color (doesn't mean they can't come close, sometimes).

You *might* be able to assume that the color would be brighter than that on the photograph, but you would never be able to know for sure.

[Mark II]

Thank you for the photo. The color is great....but the placement of the screws on the fins and aft section is priceless! The color on the payload section matches duplicolor anodized green. I'm cook'in with gas!
What I like best about rocketry -- the people
I have a copy of that photo, too. It is a much sharper print than the print of the identical photo that was in my scale pack. Some of the things that show up in this image are the somewhat mottled appearance of the red paint job on the Sandhawk, and the white spots on a couple of places. Those spots are where the supports were that the Sandhawk was resting on when it was in its cradle. The quick spray paint job was done while the rocket was resting it its shipping cradle, and those are spots that didn't get painted.

Also, if you zoom in close on the fins, you will notice a vertical stripe on the fin on the left (the one that is projecting out toward the viewer). It is darker on its upper part, on the fin's beveled edge, and is a lighter gray as it extends almost halfway down the side of the fin. This is not an artifact of the photo, nor is it a shadow - it is really there on the fin. It is some sort of paint overspray, either done at the factory or at the launch site. IOW, it is a paint masking error! :D

Finally, also notice that in addition to the antennae extending out from the payload section up near the top of the rocket, there is another antenna extending out from the fin shroud in between the two fins that are visible in the photo. Until I obtained this very sharp version of the photo, I never knew that the bottom antenna was even there; the print that came with my scale pack is not sharp enough to show it.

Now here is where I am looking for some help. One of the things that is really hanging me up on my scratch-build is trying to visualize what those fin brackets look like in 3 dimensions. I have seen some good line drawings of them, and there is a very excellent one in my scale pack, but I am still a bit mystified regarding what parts along the brackets' outer faces (where the bolt heads are) curve in, and what parts curve out (if any). I am going to need to fabricate these brackets, and even though my model will be a sport scale, I would like to get details such as these at least grossly correct. Does any one have any idea, or, better yet, could anyone post a photo, taken at an oblique angle, of a correctly detailed fin bracket?

Mark \\.

[Mark II]

Also, one other detail from the photo: if you look at the bottom of the rocket, below the white fin shroud, you will notice a few inches of the aft end of the rocket motor extending downward below the fins. This part on the Sandhawk was not painted, it was left in its natural metallic color. You could use any kind of Steel or Bronze-Steel paint (depending on how it looks to you in the photo) to paint that section.

Mark \\.

[rocketguy101]

Here's (http://scale-rocketry.tripod.com/id4.htm) a good site for data (photos) for the Sandhawk.

Also, I got a truly amazing amount of information (including the background info I posted before) from the NARTS (https://blastzone.com/nar/narts/store.asp?groupid=92400111757284) Sandhawk Scale Pack, written by Matt Steele and Craig Beyers.

Mark \\.
The NARTS scale pak says the red color is close to "lusterless red" FS # 31302 (Federal Standard color) which would look like this (http://www.colorserver.net/showcolor.asp?fs=31302) according to a website I found when I googled FS-595. Found this site (http://www.fed-std-595.com/FS-595-Paint-Spec.html) too, which is pretty interesting.

[Mark II]

The NARTS scale pak says the red color is close to "lusterless red" FS # 31302 (Federal Standard color) which would look like this (http://www.colorserver.net/showcolor.asp?fs=31302) according to a website I found when I googled FS-595. Found this site (http://www.fed-std-595.com/FS-595-Paint-Spec.html) too, which is pretty interesting.
Yeah, I saw that in my scale pack, too, but I didn't think to do a web search to find out what that color actually was. The main message that I got from the scale pack was what I had previously stated, along with the practical advice that if you are entering your Sandhawk in a scale competition, make sure that your paint color matches the color in the photo that you include in your documentation pack, whatever that shade happens to be!

What I read the scale pack to say was that there is a bit of leeway regarding what is acceptable as an accurate shade of red for the Sandhawk.

The reason that I like Krylon Red-Orange Fluorescent so much was because I used it on the only other Sandhawk that I have built so far, the ASP Micro Sandhawk, and I liked the way it came out. To my eyes, anyway, it seems to match up pretty well with the swatch of FS 31302 shown on that website. (Of course, since my model is a micro, there isn't a lot of surface area on it, and the total amount of painted surface area can affect how well a particular paint color plays.) Also remember that just because we can all view the same reference color swatch on the web, it doesn't mean that we all see the same color. Different brands of computer monitors, differences in settings on individual monitors, differences in web browsers and even differences in operating systems can all lead to greater or lesser variations in the way that each person sees that reference color. These differences may not be very great, but they will occur.

Anyway, I'm a bit open-minded on this issue, especially if we are not talking about a scale contest entry. Probably any fiery red-orange color will work. I'll make up swatches of Krylon ROF and Duplicolor Radiant Fire and post photos of them to show if either one looks like a suitable color to anyone else.

Mark \\.

[rocketguy101]

Now here is where I am looking for some help. One of the things that is really hanging me up on my scratch-build is trying to visualize what those fin brackets look like in 3 dimensions. I have seen some good line drawings of them, and there is a very excellent one in my scale pack, but I am still a bit mystified regarding what parts along the brackets' outer faces (where the bolt heads are) curve in, and what parts curve out (if any). I am going to need to fabricate these brackets, and even though my model will be a sport scale, I would like to get details such as these at least grossly correct. Does any one have any idea, or, better yet, could anyone post a photo, taken at an oblique angle, of a correctly detailed fin bracket?

Mark \\.
Here is my take, using SolidWorks, from the NARTS Pak drawings. A couple details are missing, so this may not be 100% It appears from the NARTS drawing that the shroud is split into two 180 degree segment?!? I am showing it as a single piece. Also I had a tough time getting the leading edge taper on the fin modeled--I may play with it some more.

edit: the first view of the fin assy is the "front" and the second is the "right", showing the different bolt patterns at the top and bottom of the shroud. there are 3 bolts between the fins on two sides, and 4 bolts on the others.

[Mark II]

Here is my take, using SolidWorks, from the NARTS Pak drawings. A couple details are missing, so this may not be 100% It appears from the NARTS drawing that the shroud is split into two 180 degree segment?!? I am showing it as a single piece. Also I had a tough time getting the leading edge taper on the fin modeled--I may play with it some more.

edit: the first view of the fin assy is the "front" and the second is the "right", showing the different bolt patterns at the top and bottom of the shroud. there are 3 bolts between the fins on two sides, and 4 bolts on the others.
Thanks a million, Dave! Your drawings have finally cleared up that mystery for me!

To answer your question about the fin shroud: yes, it consisted of two halves. My computer drafting skills are not nearly as good as yours; when I took drafting in high school, it was done on a piece of paper mounted on a board, and was accomplished with the aid of a T-square, a compass, a protractor, a pair of triangles, 2 or 3 lead holders, a lead pointer and a gum eraser! Anyway, I'll try to make a simple drawing in GIMP to illustrate how the two halves are laid out. But if you were to peel them off the Sandhawk and laid them out flat, next to each other, the pattern would be:

|-+--+--Fin-+-+-+-Fin--+--+-||-+--+--Fin-+-+-+-Fin--+--+-|







|-+--+--Fin-+-+-+-Fin--+--+-||-+--+--Fin-+-+-+-Fin--+--+-|


The "+" 's are the bolts
The "-" 's are just placeholders in the diagram
The double line "||" in the middle of each row in the diagram represents the space between the two half-shrouds.

The space between the two fins on each shroud has a 3-bolt pattern. The space between each of the fins and the edge of the shroud has a 2-bolt pattern. When the two shrouds are wrapped around the rocket, the 2-bolt pattern on the outside edge of one shroud adjoins the 2-bolt pattern on the outside edge of the other shroud, resulting in a 4-bolt pattern between pairs of fins on opposite sides of the rocket. Get it?

Mark \\.

[rocketguy101]

Like So? Now that I have taken a close look at my Estes Sandhawk, I see the split line -- I thought that was part of the plastic molding process.

The NARTs drawing makes it appear the shoud wall thickness goes from about 3" under the fins (basing on the length callout of the Heli-coils) to (I am guessing) about 1" at the ends. This is based on the section views showing the bolt patterns. I modeled it that way which is why it may look a little different than the earlier post.

Yeah, I spent plenty of time with paper, T-square, triangles, etc. When I first went to work ('79) we had tilt-table drafting boards with those drafting machines -- a big arm with swivels and a head that had two rulers attached at 90 degrees that could pivot to draw angles. I thought I was hot stuff with an electric eraser! We started using CAD on a mainframe system (2D) in the mid 80s. I mainly use CAD to draw models for finite element analyis or CFD work.

[barone]

.......when I took drafting in high school, it was done on a piece of paper mounted on a board, and was accomplished with the aid of a T-square, a compass, a protractor, a pair of triangles, 2 or 3 lead holders, a lead pointer and a gum eraser!.....
Oh...and don't forget the scum bag..... :chuckle:

[Mark II]

Oh...and don't forget the scum bag..... :chuckle:
:confused: :confused: :confused:

Mark \\.

[Mark II]

Like So? Now that I have taken a close look at my Estes Sandhawk, I see the split line -- I thought that was part of the plastic molding process.
Yup - you got it.

The NARTs drawing makes it appear the shoud wall thickness goes from about 3" under the fins (basing on the length callout of the Heli-coils) to (I am guessing) about 1" at the ends. This is based on the section views showing the bolt patterns. I modeled it that way which is why it may look a little different than the earlier post.
I haven't actually looked at that issue yet, even though I have spent many hours studying the drawings in the scale pack. But I have mainly focused on adding surface details to my project, rather than trying to build a finely-scaled model from the inside out.

One other question: are those really "flats" on the fin can/shroud where the fins and brackets attach?

Yeah, I spent plenty of time with paper, T-square, triangles, etc. When I first went to work ('79) we had tilt-table drafting boards with those drafting machines -- a big arm with swivels and a head that had two rulers attached at 90 degrees that could pivot to draw angles. I thought I was hot stuff with an electric eraser! We started using CAD on a mainframe system (2D) in the mid 80s. I mainly use CAD to draw models for finite element analyis or CFD work.
Part of me really likes the idea of CAD, even though I have never had the opportunity to try designing with it. I'm certainly no Luddite. But another part of me feels incredibly limited and awkward when I try to draw with a mouse. I just want to get my hands on the drawing, and manipulate real lines on real media, rather than moving pixels around on a screen. About 5 years ago, I actually went out and bought a drawing board, a T-square, triangles, leads, lead holders, a lead pointer, a compass, two scales and a French curve just so that I could work out design and construction issues with my rockets. I had not touched any of that stuff since the end of 9th grade, back in 1968! I just wish I could still remember some of the stuff that I knew from back then, like how to draw an isometric projection using just those tools. I have never used a real CAD program; I have done most of my digital drawing in GIMP.

Mark \\.

[rocketguy101]

:confused: :confused: :confused:

Mark \\.

I think he means a cleaning pad
http://www.draftingsteals.com/catalog-pencil-sharpeners---erasing-supplies-draftman-s-cleaning-pads.html

[rocketguy101]

One other question: are those really "flats" on the fin can/shroud where the fins and brackets attach?Mark \\.

That is what it looks like to me. I think the fin brackets fit onto the flats, with the boss (the round "knob" sticking out of the bottom of the bracket) going into the center hole of the flat area. The slotted holes in the fin bracket allow for adjustment of the fin angle to either add spin or to make up for manufacturing tolerances. After all the bolts are tightened down the fin is good to go!

[Mark II]

I think he means a cleaning pad
http://www.draftingsteals.com/catalog-pencil-sharpeners---erasing-supplies-draftman-s-cleaning-pads.html
Aahh, OK. I have never seen that particular item before.

Mark \\.

[Mark II]

That is what it looks like to me. I think the fin brackets fit onto the flats, with the boss (the round "knob" sticking out of the bottom of the bracket) going into the center hole of the flat area. The slotted holes in the fin bracket allow for adjustment of the fin angle to either add spin or to make up for manufacturing tolerances. After all the bolts are tightened down the fin is good to go!
And then there was the fin adjusting band, up above the shroud. Perhaps this was kept loose while the brackets were being adjusted, and then tightened down to anchor and stabilize the upper part of the fin?

Speaking of the fins, you had mentioned that these were hard to draw in SolidWorks, but they are also really hard to model in the real world. Along with the brackets, this part of the construction has kept me scratching my head for almost a year and a half. The hollow built-up method, using styrene for the skin, that is outlined in the NARTS pack would probably work well for a model of, say, BT-60 size, and you could use a stronger material to make the skin in large models, but I feel that my 2" model is stuck in no-man's land between these two scale ranges. It's too large to use styrene, and too small to use something tougher and thicker.

The problem is that not only does the Sandhawk fin have a symmetrical knife-edge bevel on the leading edge, it also tapers in thickness from the root edge out to the tip edge. The fins on the real Sandhawks were quite thin to to begin with (only 1.017" thick at the root), so when you try to scale them down... Well, you run into an issue with material - finding something that is the right thickness, that can be tapered and beveled, and yet will have sufficient strength. Also, because the root edges will be pretty thin, there may not be enough surface area on them to bond well to the surface of the airframe, so you are looking at TTW construction. For my 1/6 (approx.) scale Sandhawk, the 7.125" root edge of the fins need to be 0.17" thick (a little less than 3/16ths of an inch), and then they need to taper down to 0.086" (slightly over 2mm) thick at the tip edge, which is approx. 3.3" away! :eek: I have tentatively come up with a plan to use a lamination of alternating layers of two different types of wood with two different thicknesses, with a sculpted knife-edge bevel. If that doesn't prove to be strong enough, then it is back to the drawing board (no pun intended). You have to see my prototype to appreciate how really thin these scale fins are.

Mark \\.

[barone]

I think he means a cleaning pad
http://www.draftingsteals.com/catalog-pencil-sharpeners---erasing-supplies-draftman-s-cleaning-pads.html
That's them.....scum bags..... :D

[rocketguy101]

Mark those fins will be tough to make! Will plywood work? What are you flying this on? I built a semi-scale using 2" plotter paper core tube, but opted to make constant-thickness fins from balsa, covered w/ 110# card stock to form the sharp leading edge. A coat of CA made them pretty strong, but I am flying on an "F".

I dug out a Thiokol brochure on the Sandhawk motor (TE-M-473) and scanned it into a pdf. I had to de-res a little to fit the size limit on this forum. I think I see now why the fin shroud is split, to fit over the motor nozzle (see pg 2). The bell of the nozzle forms that metal ring at the base of the rocket.

[dwmzmm]

I've been following this thread with a keen eye; I have the vintage Estes Sandia Sandhawk
(Kit # K-51) still "in-the-bag" I've been wanting to build (if I can ever get to it). The links
to the scale data will help considerably. Thanks again and keep up the great dialog. :)

[rocketguy101]

This bird is deceptive...it looks fairly simple as a 4FN model, but that fin shroud/bracket assembly and the antennas can drive you nuts, not to mention the fin planform as Mark has already pointed out. It has always been one of my favorites. I have two vintage Estes kits from the 70s...one I built several years ago and didn't do it justice. The other is in the bag (but opened).

I look forward to you posting pictures of your Sandhawk if/when you build it -- I always enjoy seeing your models here and over at the NSF forum!

[dwmzmm]

This bird is deceptive...it looks fairly simple as a 4FN model, but that fin shroud/bracket assembly and the antennas can drive you nuts, not to mention the fin planform as Mark has already pointed out. It has always been one of my favorites. I have two vintage Estes kits from the 70s...one I built several years ago and didn't do it justice. The other is in the bag (but opened).

I look forward to you posting pictures of your Sandhawk if/when you build it -- I always enjoy seeing your models here and over at the NSF forum!

Are you saying the Estes K-51 kit is fairly difficult to assemble? It's suppose to be a Skill Level - 2 build (at least, that's what the catalogs say). I'll have to go find it (the kit) in my
stash in the several large boxes I have and maybe pull the instructions out and study it.
I was thinking it (the Sandhawk) would be somewhat similar to the re-released D - Region
Tomahawk (which I also have, but haven't assembled yet).

[Mark II]

Mark those fins will be tough to make! Will plywood work? What are you flying this on? I built a semi-scale using 2" plotter paper core tube, but opted to make constant-thickness fins from balsa, covered w/ 110# card stock to form the sharp leading edge. A coat of CA made them pretty strong, but I am flying on an "F".

I dug out a Thiokol brochure on the Sandhawk motor (TE-M-473) and scanned it into a pdf. I had to de-res a little to fit the size limit on this forum. I think I see now why the fin shroud is split, to fit over the motor nozzle (see pg 2). The bell of the nozzle forms that metal ring at the base of the rocket.



A 1/64" plywood core layer, in the shape of the whole fin,
sandwiched between two layers of 1/16" basswood, in the shape of the fin, minus the knife-edge.
each piece of the basswood layer is sanded, on its upper side, in a smooth slope from 1/16" at the root edge to 0.5mm at the tip edge.
the flat, unsanded side of each basswood layer is epoxied to opposite sides of the core layer. The portion of the core layer that will be under the knife-edge bevel is left uncovered.
Bondo is applied to the uncovered core over the knife-edge layer on one side and is scraped and sanded to match the desired bevel for that side. When the Bondo on the first side has cured, the fin is flipped over and the process is repeated on the other side.
a skin consisting of another layer of 1/64" plywood is bonded to the top layer on both sides of the fin. A piece corresponding to the outline of the fin minus the bevel is bonded on each side first, and then another piece to cover the bevel is bonded onto each side. The inner edges of the bevel pieces are themselves beveled where they will meet at the leading edge of the fin so that they maintain a sharp edge when they are bonded together. Aeropoxy 6209 will be used for the bonding, and the lamination will be subjected to constant pressure (firm, but not crushing) until the epoxy cures. The Aeropoxy will be used in order to give the laminated layers the strongest bond that I can reasonably accomplish.
The total lamination will be 11/64" thick at the root edge, or 0.171875", close enough to the target thickness of 0.17". At the tip edge, it will consist of the three layers of 1/64" plywood (the core plus the two top skins), combined with the half-millimeter edges of the two basswood layers. The sum of 3/64" plus 1mm equals 0.086245", close enough to the target thickness of 0.086".

The unresolved question is whether the resulting fin will be stiff enough.

This is one of the ideas that I had for constructing the fins, anyway.

The attached photos are of a stack of the unlaminated layers for one of the fins, before they are bonded together and before the Bondo is added. This is the "prototype" that I mentioned before. The stack includes the top "skin" layer, but only the part that covers the flat part of the fin. The first photo is a shot of the root edge, the second is a shot of the tip edge, and the third is a shot of the overall fin. In the second shot, the layers aren't too tightly held together. If I were to get them tighter, the clamps that I would need to put on would block the camera's view of the edge. The root edge of the fin is a little over 7" long, and the chord is approx. 3-5/16". What is missing from this prototype is the TTW tab on the root edge; I forgot to add it when I traced and cut out the layers.

Mark \\.

[rocketguy101]

Are you saying the Estes K-51 kit is fairly difficult to assemble? It's suppose to be a Skill Level - 2 build (at least, that's what the catalogs say). I'll have to go find it (the kit) in my
stash in the several large boxes I have and maybe pull the instructions out and study it.
I was thinking it (the Sandhawk) would be somewhat similar to the re-released D - Region
Tomahawk (which I also have, but haven't assembled yet).
No, no! Sorry thats what I get for posting at midnight--the 51 yr old brain wants to be in bed by 10:30 ;)

No the Estes model is pretty straight forward, with a lot of great detailing molded-in. I did not install the antennas, because I figured they would break off after the first flight. Somewhere I had read (perhaps Model Rocketry magazine?) someone suggested replacing the plastic antennas with music wire--I was lazy. There were some blemishes in the plastic parts, especially the nose cone that I had to fill in with Testors putty. But the K-51 is a great kit and is really impressive-- here is a shot of mine at lift off.

When I wrote the above, I was thinking of scratch built models.

http://www.geocities.com/rocketguy_101/images/SandhawkFly.jpg

[dwmzmm]

No, no! Sorry thats what I get for posting at midnight--the 51 yr old brain wants to be in bed by 10:30 ;)

No the Estes model is pretty straight forward, with a lot of great detailing molded-in. I did not install the antennas, because I figured they would break off after the first flight. Somewhere I had read (perhaps Model Rocketry magazine?) someone suggested replacing the plastic antennas with music wire--I was lazy. There were some blemishes in the plastic parts, especially the nose cone that I had to fill in with Testors putty. But the K-51 is a great kit and is really impressive-- here is a shot of mine at lift off.

When I wrote the above, I was thinking of scratch built models.

http://www.geocities.com/rocketguy_101/images/SandhawkFly.jpg

Nice lift off picture! That's what I like about the Sandhawk; the colors really make it standout.

[Mark II]

The instructions for the Estes K-51 Sandhawk are available here (http://www.dars.org/jimz/k-51.htm) 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" :rolleyes: . 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! :chuckle:

Mark \\.

[rocketguy101]

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" :rolleyes: . If I had only known...


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



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)

[jetlag]

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?!!!

[Mark II]

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 \\.

[dwmzmm]

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 :( ).

[rocketguy101]

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.

[rocketguy101]

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 (http://groups.yahoo.com/group/scaleroc/?yguid=170333412) for those interested.

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