12 posts • joined 20 Feb 2012
Area 51 is old news
I enjoyed reading a book on the subject two years ago. There were plenty of anecdotes and personal accounts. One was about using Area 51 to test the radar profile of a prototype spy plane. They were careful to hide the plane whenever Russian spy birds flew over, but the Russians took an IR afterimage of the shadow that the model had cast on the desert floor. They sent a copy to the US Army, just to rub it in.
Another chapter was about how the U-2 test flights started so many UFO rumors. They were calibrating the camera platform, and they would fly huge patterns over much of the ConUS. Nobody tried to debunk the UFO stories, because those distracted so many people from the true source of the sightings.
Area 51: An Uncensored History of America's Top Secret Military Base
By: Annie Jacobsen
Sold By: Hachette Book Group
Have you checked your GPS receiver for accuracy at altitude? The last time I used a Garmin through the window of an international flight it was under-reporting altitude by almost 10% as compared to the jet's navi display. I don't think they anticipated their gear being used at 30,000'.
Re: Rods are out. Rails are in.
Too much spin or side wind on the wings in the lower altitudes will batter the craft and try to rip the launch bearings off of their mounts. I think it would be worth an ounce or two of paper streamer to keep everything pointed into the wind.
Rods are out. Rails are in.
For heavy rockets, those in the biz use a square Aluminium C rail. That rail could replace the apex of your beam. So, the flat side of the beam faces up, and the apex points down. Then a pair of Delrin rail buttons* are screwed to the top of the plane, and they slot into the open end of the rail. The bottom end of the rail just needs a thru-bolt to stop the buttons from sliding all the way through. That also eliminates the need for a plate and bumper at the back of the plane.
Hang a drogue (sea anchor style or just a paper streamer) off of the bottom end of the beam so that it always points into the wind, and then you shouldn't have trouble with the plane twisting and binding in the channel. Any pilot knows you take off into the wind.
*For example, see: http://stores.whatsuphobby.com/-strse-Components-cln-Railbuttons/Categories.bok
Re: Ice issues on the launch Rod ...
Don't forget the batteries. LiPo has a fantastic weight/energy ratio, but they might set your truss on fire if the current limiting isn't worked out right.
Another congressman publicly admits he can't distinguish between fantasy and reality.
And he’s got a two year deadline. Meanwhile, we’re still waiting for the first flying car that everyone was supposed to be driving by 2000. It’s only taken 50 years for the Dick Tracy watch to go on the market. Getting a fingerprint scanner to 99.9% reliability on both accept and reject in a split second shouldn’t take more than twice that.
And, he’s talking like the NRA is dragging its’ heels on gun safety. Doesn’t the NRA already outspend the feds when it comes to gun safety programs?
It doesn't matter. The whole execution of the concept is a joke
First, you have to get 150 signatures before the petition becomes searchable. That means you have to publicize your petition somewhere else to get things rolling. It also means that they get parallel petitions going, because you can't check before you create one to see if someone has already started the ball rolling. This dilutes support by spreading it across several petitions.
Second, if you bookmark the petition you signed, then, when you go back to check for the response, they don't link to it. You have to search a different area for responses.
Third, the responses get taken down after a few weeks. You can build up signatures for a month, but they can't keep a couple paragraphs of response around for half a year?
Re: Wind and Spin
Stop repeating yourself and go look at the launch of Vulture or a half dozen other balloons with a camera in the payload. The images are dizzying. If a few ounces of paper streamer will stop that, then I say, "Why not?" It certainly can't hurt.
Wow. Thanks for the mention in the article. Here's something I thought of after I hit Submit the last time.
The launch has two phases. In the balloon ascent phase you are mostly worried about spin and wind buffeting the conjoined craft. In the launch phase I gather that you want the rocket plane to point up to gain additional altitude. That's smart, because you won't get any lift from those small wings until the craft is back down to ~10km. Anyway, there's a pretty lightweight solution to this: Mount an R/C servo in the beam.
If you shorten the back lines so the beam is almost horizontal, then the wings and body present less surface area to the wind. You would even get some lift from the wings if you put a streamer tail on the beam to point everything into the wind. Once you get above the jet stream, then unwind the rear lines to lower the beam into launch position for the rocket plane.
This can be accomplished many ways. Most of them are fairly simple and foolproof. A straight timer solution would only take a few 556 chips. One to generate the PWM signals (10/90 for ascent, 90/10 for launch) to the servo. Another to trigger the first one into switchover after ~45 minutes.
Servos are also easy to modify for continuous winding if you need more than 270 degrees of rotation to get into position. Then just tie a bead to the end of the line and have it drop off the pulley so it doesn't wind back up.
Also, my aviation experience is limited, but, as far as it goes, ice buildup is a problem when flying through thunderheads (rain or snow clouds). If you are launching on a clear day, then any ice would sublimate as fast as it lands. Private planes fly all day long in clear skies without wing heaters.
I'm too lazy to downvote all the sonar/ultrasonic rangefinder commentards
In case you missed it: This is a LAWNMOWER we are discussing. How is an ultrasonic transducer going to hear the echo of a tic-tic-tic over the din of a barely muffled single cylinder engine and the rattles generated by a slightly out-of-balance whirling blade?
Pulsed IR Beacons in the corners of the garden and a detector mounted on a goniometer FTW. You don't need to make the beacons transmit unique codes. You just need to strobe them so you can overdrive the power for extra brilliance at a low enough duty cycle to keep from smoking the junction. It also gives you noise rejection from steady-state sunlight glinting off of the prized glass garden orb.
The mower will start at a known location, and constantly update it's position from there. If you map the location of the beacons, then you should be able to quickly servo to one side of where you expect each beacon to be, Then do a slower scan to precisely locate that beacon. Then move on to the next one. Calculate your updated position while the sensor whirls back to start.
That's sorted, then. Oh, the weather was too nice for a coat, today. I'll just leave, then.
The model I saw earlier had a V tail. This is ideal for using Delrin LOW DRAG Rail Buttons on the top of the rocket plane body and hang it on a Standard Launch Rail that runs along the bottom of the truss.
You can't perch a plane of any weight on top of a hanging truss. Long before it reached launch altitude it would simply flip over, fall off and auger into the ground. Keep the center of gravity low and hang the plane under the truss, out of the way of the suspension lines.
Rockoons were developed 60 years ago
Check the history books for what worked then. A single balloon launches the rocket at an angle to miss the balloon. See http://en.wikipedia.org/wiki/Rockoon, for starters.
You could hang the rocket on a rail running along the lowest apex of the truss, with the instrument deck looking down at it. You could also nest the rocket inside the truss -- that's been done before, too.
Also, hang a streamer from the bottom end of the truss. It might keep the truss from spinning madly, and keep the rocket pointed into the wind during launch. The solid instrument deck could act as a sail to catch the wind and start things spinning. I don't know how much wind acts on the truss. Wind should push the balloon downwind almost as fast as it is blowing, but all the camera footage I've seen from prior launches seemed to feature an incredible amount of wind noise on the soundtrack.