rocket launched rogallo glider

I am under pressure now!

I have changed the colour of the wing to give better visibility. Changed the nose cone from home made to machined and modified it to take the 808 keychain camera. Also altered the tail mounting which had been held on by filament tape after a rough test glide landing. Currently we are in the midst of the fire season and there are wildfires burning in various states. Probably a good idea to wait a couple of months until the cooler weather as the launch area is covered with waist deep grass.

I am putting together an updated version of the glider. Here is a photo of the carbon fibre frame roughly assembled with filament tape at this point. I am waiting on some more carbon fibre, hinges and servos to complete it. The idea is to have room for electronics such as an autopilot around the glider CG so I have extended the ebay back well back behind the CG to where the slider for the wing push rods stops(the bulk head is situated just in front of the slider). The wing spars are mounted on Dynabolt eye bolts which are held in position by screws secured to a section of polypropylene??(an old kitchen chopping board)
The Vtail from the first glider can be unscrewed so I can transfer it to this one but this glider may have to be longer than the original to accomodate a larger slider for the wing push rods which are pulled forward by elastic bands.
I have been looking at the info for the APM2.5 autopilot but it seems more complex than necessary for what I am trying to do.

Has anyone tried any other autopilots? In this application it would simply be required to activate on deployment from the booster and control 2 servos in a return to launch scenario. APM2.5 has capabilities well beyond that so I wonder is there anything simpler and cheaper around?

I have an APM 1 and an APM 2.5. I'm unimpressed with their ground station software. Programming a mission, even something as simple as "glide to this point and circle it until you get to 50' AGL, then fly a straight line on a bearing" is beyond my programming ability, and I am a software engineer by trade with a graduate degree in cognitive science. Flight stabilization does work remarkably well on my Bixler--I can fly it in wind that would otherwise be beyond my piloting ability. 3DR do publish a "parameters file" for the Bixler, which means I don't need to tune them for that airframe.

Tuning PID parameters for a particular airframe (on any autopilot) may take a lot of trial and error, especially with an airframe that violates some assumptions the AP makes. You may want to first get to a point where you're comfortable flying it manually. If nothing else, you may like the ability to take over control if the AP starts doing something funny. APM, for instance, occasionally tires to fly East-Southeast from here: if a coordinate parameter is missing or invalid, it likes to interpret it as 0ºN 0ºW, a place in the middle of Gulf of Guinea.

Ari.

iter said:

I have an APM 1 and an APM 2.5. I'm unimpressed with their ground station software. Programming a mission, even something as simple as "glide to this point and circle it until you get to 50' AGL, then fly a straight line on a bearing" is beyond my programming ability, and I am a software engineer by trade with a graduate degree in cognitive science. Ari.

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It sounds daunting Ari given my knowledge of programming and software is absolutely minimal. If I was to purchase an APM2.5 I would probably have to buy an electric v-tail glider as well to test it out before launching with the rocket glider. Sounds like quite a bit of money.

philip said:

I would probably have to buy an electric v-tail glider as well to test it out before launching with the rocket glider. .

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Or I could put a balsa v-tail on my Easystar.

philip said:

Or I could put a balsa v-tail on my Easystar.

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I modified the Easystar to a v-tail and tried it out today flying in a strong gusty wind at the launch site. It was much less stable in the roll direction and it took quite a bit of work to keep it horizontal. But if I buy an autopilot for the v-tail glider this will give me something to test it in.

I have bought an APM2.5 autopilot and am getting close to having that ready it looks like it will fit in the glider ebay which I have slightly enlarged. Trying to sort out a couple of glitches but it looks promising. It can be switched between "manual", "stabilise" and "return to launch." During boost it would have to be set to manual so that the glider isn't fighting to level out while enclosed in the booster. Then at glider deployment it could be switched to either RTL or stabilise. This would require flicking a switch on the RC transmitter when the glider slides out of the booster(and not before as the servos would be damaged). The APM has GPS and a transmitter which can send data to a ground station. If the rocket is out of sight then I would be relying on the data from that to know when to switch from manual control. Question is whether the GPS would remain locked during boost so that altitude data can be sent back to the base station?

MarkII said:

Warning: I brake for invisible squirrels

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What do you do for the visible ones?

:wink:

philip said:

Here is the video of the glider. Unfortunately the flight is over pretty quickly, but the glider and booster both came down intact. I should have applied some left rudder to pull the glider out of the spiral and prolong the flight. The question is how to improve the design and get more altitude? It was launched with a G80-4t (cost around $60)and got to 616ft so that is a lot of money for a short flight. Obviously I need to look at trimming down the weight and streamlining the deign but an RC rogallo glider is always going to be a reasonably heavy payload. [video=youtube;B_B3rSx0-bQ]https://www.youtube.com/watch?v=B_B3rSx0-bQ&feature=youtu.be[/video]

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Where are you getting your G80s? That's pretty pricey... I've typically seen them in the $25-30 range.

If you're going to fly this a lot you could consider AeroTech hobbyline reloads. The G76G should be about what you need for $15 each @ Sirius Rocketry and no HAZMAT fee. The one downside is you might want to toss in an extra bag of igniters- AT Mojave Green motors are famously hard to light.

This is a cool project- I can't wait to see onboard video!

A lot of things are pricey when you have to ship them across the Pacific.

kj