Double Shuttle has double cato

[aerostadt]

The Double Shuttle opened just about at apogee, perhaps going up a bit, which looked cool. I caught some pictures of the gliders circling. My half-shell gliders tend to fly naturally in circles and are fairly robust. In other words they are aerostadt-proof. The elevons on this model are set by paper-clips and they were set fairly high. For some reason one of the gliders tends to dive a little bit towards the end of the flight. I need to go back and inspect the gliders and weight them.

 

[Cl(VII)]

Congrats on what looks to be a very nice (high degree of difficulty) flight.

 

[burkefj]

That was a very nice flight and one of the gliders was perfectly trimmed I'm glad I got to see that in person. They did a sort of bomb burst at apogee that looked really neat

 

[aerostadt]

I got some terrific lift-off pictures from Jim Wilkerson/Tahoma Photography.

 

[aerostadt]

Nadine(Photos by Nadine) caught one picture of the Double Shuttle from the side showing both motors firing.

 

[aerostadt]

Braden at rocketvlogs has a terrific LDRS-39 video for sale. Here is the video of the Double Shuttle. You can see the Double Shuttle spinning a little bit on the way up. I am going to back through the timing in this video and look at the ejection charges. The ejection charge went off a little bit early and think, because I drilled down one of the delay charges. I think I see a sign of the other ejection charge firing way later. As Frank pointed out (the trim) and my daughter noted a few years ago that one of the gliders does not glide very well. I think I have figured out the culprit. Unbelievably, both gliders have the same red/blue coloring on the wing tip fins. However, I have found that the glider with the red stripe on top has the vent tubes and the other glider with the blue stripe on top has vent holes. Both gliders identically weigh 12.5 oz and the c.g. on both gliders is nearly identical. So who is the culprit? I put the each glider on top of a 2"x4" along the long axis. The red-stripe glider balances fine for "roll". However, the blue-stripe glider definitely rolls toward the side with the launch lugs. I don't know if the launch lugs are the prime problem, but the blue-stripe glider is the leading suspect. If you look at the video, it looks like the bad glider is perhaps rolling slowly so the that the wing cannot no longer provide lift for gliding. If you have the LDRS-39 video, you can see the flight between time 20:43 and 21:34 .

 

[aerostadt]

The launch lugs are on the left side of the blue-stripe glider, so I put rail buttons on the opposite side. I checked the glider on top of the 2"x4" and the roll moment is gone. I find it hard to believe that this slight adjustment really changed things, but I not planning any more changes before the next flight.

I bought some more F24's and the time delay is listed as 4 seconds. I think I drilled down the delay on one of the F24's on the last flight. It looks like gliders separated about 3 or 4 seconds after ignition. I can see a puff of smoke from the good glider at about 7 or 8 seconds. This is telling me that there can be quite a difference in the time delay for the ejection charge. I will have to fly the Double Shuttle again. Hopefully, I can this at one of the rocket meets in the Fall.

 

[burkefj]

It looked to me like one was more nose heavy and/or slightly less up elevon when watching, not just a roll issue.

The launch lugs are on the left side of the blue-stripe glider, so I put rail buttons on the opposite side. I checked the glider on top of the 2"x4" and the roll moment is gone. I find it hard to believe that this slight adjustment really changed things, but I not planning any more changes before the next flight.

I bought some more F24's and the time delay is listed as 4 seconds. I think I drilled down the delay on one of the F24's on the last flight. It looks like gliders separated about 3 or 4 seconds after ignition. I can see a puff of smoke from the good glider at about 7 or 8 seconds. This is telling me that there can be quite a difference in the time delay for the ejection charge. I will have to fly the Double Shuttle again. Hopefully, I can this at one of the rocket meets in the Fall.

 

[aerostadt]

It looked to me like one was more nose heavy and/or slightly less up elevon when watching, not just a roll issue.

Yes, this is food for thought. I guess there are at least 3 candidates for the problem. Weight or c.g., elevon position, and roll. On the previous page of this thread, post #103, my daughter shows a video of a bad DS crash. (The red glider goes straight in, but the blue glider behaves maybe a little bit like the blue glider did at LDRS39.) My red (stripe) glider shows signs of the repair that was done in post #108. In that post I stated that 1.84 oz was removed from the nose cone. However, maybe some of that weight was added back on during the reattachment of the nose cone. In the latest LDRS39 flight the red glider does well, which implies that the lobotomy on the nose cone in post #108 may have worked. I just checked the glider weights again. I get 12.5 oz for the red stripe glider and 12.8 oz for the blue stripe glider, so only 0.3 oz difference. The c.g. location looks about the same to me for both gliders. It took a lot of re-work for the red (stripe) glider nose cone. At the moment I am not sure that I want to do this for the blue glider. I am wondering if the early separation of the DS at LDRS39 maybe forced the elevons down on the blue glider.

 

[aerostadt]

I have found a loose hinge on the left elevon of the blue glider. I will definitely repair that.