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Estes Astron Skydart II from Arkansas

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Crawf56

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Built this a couple of years ago; didn't see much on this model, so decided to post a thread. :)

m_IMG_0578.jpg m_IMG_0581.jpg

...and we're done.

(Just kidding...:wink: )
 

Crawf56

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The Skydart has a center section that is ejected at altitude, allowing the main body (glider) to glide back down.

So, here is the glider:

m_IMG_0584.jpg m_IMG_0582.jpg
 

Crawf56

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Note that there is a good on-line build on Youtube:

[video=youtube;CrbnO6jHNcM]https://www.youtube.com/watch?v=CrbnO6jHNcM[/video]
 

Crawf56

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Note that the Skydart has an Elevator (at the back of the wing) that must deploy:

m_IMG_0579.jpg m_IMG_0580.jpg

There is stretchy, rubberband-like chord that pulls the Elevator up into position after the core tube has been ejected. There is also a small plastic screw just under the rudder that helps adjust the 'stop' position of the Elevator, so you can get the best glide.
 

aerostadt

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Another nice thing about a "pop-pod" is that in some models lead weight can be attached to the forward end of the pop-pod. This brings the c.g. forward during the boost phase. When the pod is ejected to activate the elevons the extra head-end is also removed from the glider model along with the dead-weight of the burnt-out motor. Since the motor is ejected, the model is classified as a boost-glider. If the rocket motor stays with the model and another is ejected, the model is classified as a rocket-glider.
 
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Crawf56

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Another nice thing about a "pop-pod" is that in some models lead weight can be attached to the forward end of the pop-pod. This brings the c.g. forward during the boost phase. When the pod is ejected to activate the elevons the extra head-end is also removed from the glider model along with the dead-weight of the burnt-out motor. Since the motor is ejected, the model is classified as a boost-glider. If the rocket motor stays with the model and another is ejected, the model is classified as a rocket-glider.
Yup! Here is the "pop-pod" [I like that term]:

m_IMG_0587.jpg m_IMG_0585.jpg m_IMG_0586.jpg

The middle picture shows a close-up of the weights [washers] at the nose section. Also shows the engine hook and the tab which holds the Elevator down during launch.
 

Crawf56

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And the pop-pod going into the Skydart:

m_IMG_0588.jpg m_IMG_0589.jpg m_IMG_0590.jpg

You have to REALLY be careful loading the parachute, and in the left pic I have actually done it wrong. Rather than folding the chute as with a standard rocket, with the Skydart simply 'roll up' the parachute around the tube of the pop-pod.

Note how the wooden tab on the pop-pod is holding down the Elevator.
 

Crawf56

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Note that this Skydart was built about two years ago. It stayed in a cool, somewhat damp environment.

Consequently, some of the tape is coming up, a little:

m_IMG_0591.jpg

I trimmed the raised piece that I am pointing at, and the glide test went well. But I had issues in flight that might have been caused by the age of the tape holding the Elevator.
 

Crawf56

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Alright let's LAUNCH:

m_IMG_0618 (2).jpg m_IMG_0619 (2).jpg

I used an Estes B6-2 motor for the first flight, per the instructions.

Overall, the flight went well. Wind was less than 10 mph; the Skydart went fairly straight up (underside of the wing was facing the wind direction).

The pop-pod came out fine, parachuted down to within 30 yards of the launch pad. [I have a center hole in the pop-pod parachute to reduce drift.]

For about 2/3 of the way down, the Skydart flew great; in a big circle (50 yard diameter?), turning slowly to the left. However, it tipped to the left more as it got closer to the ground. It landed right-side up, but I am concerned that the Elevator hinging needs to be replaced.
 
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ascastil

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Dug this out of the build pile and working on it now. Pretty excited to try out a little glider.
 

Crawf56

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Dug this out of the build pile and working on it now. Pretty excited to try out a little glider.
Be sure to do your glide test before flight. Pretty good little glider.

I hope to attempt an RC version, soon (mid-2017).
 

georgegassaway

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The Skydart is one of my favorite glider kits. Maybe my #1 favorite. I liked the looks, and it was pretty reliable

I hope to attempt an RC version, soon (mid-2017).
Years ago I did a 2X Scale-up using mixed elevons. Worked nicely, but was a bit tricky due to the engine propellant mass being burned off. So if it was trimmed for the right glide CG, then it was tail-heavy at liftoff and trickier to keep the boost under control. If I moved the boost CG a bit more forward to make the boost easier, then it was nose-heavy for glide. If I did it over again, i'd probably use the water ballast trick, some water in the nose at liftoff, that drained the water during boost, so the glide CG was good and the boost CG was good. I used that method on a couple of models, my old X-1 and the booster for the Orbital Skydart Project.

The wing on the 2X model was .55" thick blue foam. With slightly rounded edges, being that thick the glide was not as good as it could have been if i'd used something thinner to make the wing, like say 1/4" balsa. Or use Depron Foam as Frank Burke does on so many great models, and add some fiberglass cloth to the leading edge for ding resistance (or simply inset some balsa for the first 1/2"-1" or so of the leading edge, the rest as Depron.

Also if i made another, I'd probably make it smaller than 2X. Such as 1.6X using a BT-60, or maybe a bit smaller if I wanted to only fly it on 18mm C6 power (probably 1.3x to 1.4X using BT-55). Although, 2X was about right for D12 power, as far as D12 boost velocity, at a glide mass of about 11 ounces. But that was a bit overweight for D7 and E6 reloads. So, on second thought, if i did a new one, smaller would mean committing to at most C6 power (Could consider D7 and E6 loads, but the cost these days..... sizing for C6 is very attractive).

Might be possible to do with an internal pop-pod, put all the radio gear (the smallest and lightest practical) into a blow-molded nose cone, including one rudder servo (but would have to add a lot of tailweight to balance it out). Or, maybe put R/C inside the cardboard side air scoops that I never have bothered to use.....but that could indeed be the way to go for R/C and still use an internal pop-pod. Yeah. Never thought of that until now.

I did make up a BT-50 sized test model using just rudder-only to steer it, and rudder-only worked. But the radio gear and servo were inside of the BT-50, so the only way I flew it was piggybacked on a D12 powered rocket. Actually what I really wanted to do was two BT-50 Skydarts of different colors, on both sides of that booster, so after ejection there would be two R/C Skydarts flying back, with a 2nd pilot flying the other one.

2X Skydart info: https://georgesrockets.com/GRP/GLIDERS/skydart/skydart.htm




OSP info: https://georgesrockets.com/GRP/GLIDERS/OSP/OSP.htm






Rudder only BT-50 model for "Skydart Twins": https://georgesrockets.com/GRP/GLIDERS/Twingliders.htm



 
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Crawf56

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George, be aware that when I follow your links (posted above), I can get in your website articles.

But when I come from your main page, I can't get your website headings to take me to your articles. All I get is error messages.

I tried Chrome, Explorer, and Firefox. For example, if I click on "Twin Gliders", I get an error message ("page not found").
 

georgegassaway

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Yeah, something got screwed up when my website got reinstalled a few years ago, folder in the wrong place or something.

Have not gotten around to fixing the issue.
 

Crawf56

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Yeah, something got screwed up when my website got reinstalled a few years ago, folder in the wrong place or something.

Have not gotten around to fixing the issue.
Please fix your website! There is a tremendous amount of good information. :cool:
 

Crawf56

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Back to the Skydart....

While looking in the hobby/craft/sewing section of Wal-mart, found some possible replacement chord for the "elastic string" used to hold up the elevator on the Skydart.

m_IMG_1333.jpg
 

Faroutspacenut

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Great thread - sorry to jump on a year later.

I'm just finishing up the build on this same kit (started almost a year ago) I've noticed that the booster tube is VERY snug inside the glider airframe. It goes in ok but hard on the way out. Is this going to be a problem? I stiffened the forward green paper ring with CA and sanded it down, but I think the washers may be the culprit. Should I attempt sanding/grinding those down some for a smoother fit?

Also, I can't find the pin no the elastic that holds up the elevator during the glide phase. Any suggestions on replacements? I'd love to see a close-up picture of how that setup works - it's not clear at all in the instructions. Will look for elastic as suggested in the previous post.

This is my first boosted glider, so have a lot to learn.
 

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Skydarts are cool. A rocketeer named Buzz Nau came up with a modified elevon actuator mechanism using a small bent wire hook, two straight pins, and a rubber band. Removable and easily replaceable.

You can see one of the straight pins and the hook on my old Sky Dart clone.

005.jpg


Buzz's blog has a few pictures as well.

https://www.cv41.org/personal/gallery3/index.php/bnmr/collection/estes/sky_darts/skydart


Some notes on this mod on Chris Michielssen's blog.

https://modelrocketbuilding.blogspot.com/2017/03/buzz-naus-skydart.html
 

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Nice thread! Always fun to check out things I know nothing about, like gliders.
 

Crawf56

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Having trouble getting stuff uploaded. Will keep posting pics in a rather arcane fashion.
 

Crawf56

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Great thread - sorry to jump on a year later.

I'm just finishing up the build on this same kit (started almost a year ago) I've noticed that the booster tube is VERY snug inside the glider airframe. It goes in ok but hard on the way out. Is this going to be a problem? I stiffened the forward green paper ring with CA and sanded it down, but I think the washers may be the culprit. Should I attempt sanding/grinding those down some for a smoother fit?

Also, I can't find the pin no the elastic that holds up the elevator during the glide phase. Any suggestions on replacements? I'd love to see a close-up picture of how that setup works - it's not clear at all in the instructions. Will look for elastic as suggested in the previous post.

This is my first boosted glider, so have a lot to learn.
SNUG BOOSTER TUBE (or "pop-pod") - Yes, I also have had this problem with a recent Skydart. Sand, sand, sand is what I did. The tube should come out with a "light or medium" tug. The tube should not fall out.

There is a tab on the Tube that holds the Elevator DOWN in flight (actually, level with wing). When the tube/pop-pod ejects, it "frees" the Elevator, and the elastic (or rubber band) pulls the Elevator up.
 
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