There is a heated discussion below about quadcopter vs. fixed wings for agricultural applications and I mentioned I would write up how Agribotix selected the RV Jet as an airframe.
Briefly, a fixed wing is roughly five times more efficient than a quadcopter for a given weight and configuration (approximated by the glide ratio and validated through our experimentation). Since farmers typically work in quarter and half sections throughout the Midwest, this means the airframe should be capable of surveying 320 acres, which is practically possible only with a fixed wing.
However, all fixed wings are not equal. A flying wing is much more durable than a traditional airframe, in addition to packing smaller and being easier to set up and tear down. We experimented with a number of different flying wings, but found the best overall characteristics to lie with the RV Jet. If you're interested in more details, take a look at our blog post over at http://agribotix.com/blog/2014/5/26/the-agribotix-journey-towards-selecting-an-airframe
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Thanks, for the good wishes, and good info!
That is very interesting to many of us, thank you.
You are being a bit unfair to the Penguin as with a few mods (Magnets for the cabin, clips for attaching the wings, stiffening of the tail before gluing it, protections at the front / bottom), it would take only 30 seconds to mount on the field, and an APM stabilize mode guarantees safe landings if you take your hands off the RC 10 meters before landing :-)
Hand launching is super easy too, and there is an abundance of space and payload. But I agree that protecting the front / bottom is not a quick mod, it takes time and competences.
About the long wings RVjet : did you have to go through a few mods also ? Like swapping the acrylic nose for something more durable, make a whole for the camera to shoot south, etc ??? How easy was the hand-launching ?
Cheers
The post was definitely not intended to disparage the Penguin. It's a great airframe, but our experience led us to a flying wing. The Penguin also requires tools to assemble and tear down, which was a serious drawback in the field.
We use a foam nose on the RV Jet and bored a hole for the camera to shoot directly downward.
We found that hand launches were never as consistent as we would have liked, so we moved to a bungee launch before the start of this season. Our bungee system is extremely easy to use with the RV Jet and has had a 100% success rate over hundreds of flights so far.
:-) You are very clear in your argumentation, which makes you highly credible.
Because of you, I am getting curious about the RVjet.
About the whole you drilled, which I guess is about 2 inches or 5 cm large... Isn't it disturbing the central landing skid / rigidity ?
Also, I want the easiest system available for my students, and there is maybe even easier than the Penguin, except launching, but if you say now that bungee launching is fine then...
Would there be a way to have a link for the bungee you are using ?
And last question, would you say the RVjet is for absolute beginners ? Or rather intermediate level ?
The bore hole is around 2 inches in diameter just left of the landing skid. We mounted a window over the hole to protect the camera lens, but, even without that element, I don't believe we affected the structural integrity.
Our bungee launch system is incredibly simple. We tied a piece of 8 mm elastic cord to a string that loops around the hook on the landing skid on one side and around a stake in the ground on the other. The user then place tension on the cord and the mission begins once an acceleration threshold is reached. We've trained around a dozen users this season and never had any problems with the launch.
We essentially only fly autonomously, but the Penguin is much easier to handle in manual mode, if that's what you're asking.
All right, I have now to find an RVjet for sale in Europe...
Thx again Daniel, good luck in your autonomous training :-)
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