Hello, my team and I at Purdue University are planning to build a UAV that will be able to guide itself with GPS and a digital compass to way points. None of us have experience with R/C planes. Initially we were planning to use an Easy Star because it seems very crash safe. However, I recently learned about the Super Cub. The extra space inside is a great improvement over the Easy Star, but the front mounted prop is disconcerting. Is it even reasonable to choose a foam plane? I am worried about crashes due to our inexperience and figured that foam would be more resilient than balsa.We will probably be using an HP R707 digital camera with its cover removed for photography, it weighs 4.7oz. I suspect that the additional electronics will weigh about 4oz. Conservatively, estimate 10oz of extra stuff beyond flight essentials. Which plane would you recommend? Perhaps there is another option worth looking into?We are also thinking that a LiPo + brushless upgrade would be needed to handle the additional weight as we would like to see at least 30min of flight time. What suggestions do you have in this area?Would a foam plane without ailerons be stable enough to turn by just using the rudder as well as be able take decent quality photos? I noticed the GeoCrawler projects use a thermopile sensor to maintain level flight would we need that as well? We are assuming that the elevation reading from the WAAS enable GPS module will be accurate enough (~5m) for the plane to maintain its elevation. Do we also need to include a barometric altimeter?We would like to spend <$800 total as we are paying out of pocket. Cheap but not flimsy is what we are going for. We are designing a custom PCB for the course that will control the plane. It is based around a Freescale 9S12A64 microcontroller. Interfacing isn’t really a concern for us as we have experience with a wide range of devices. The plane, its additional parts, and the autopilot program are what we anxious about.Thank you for all of your help.David
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Hi guys,
This plane (I already own one for playing ;)) ). Could be good platform for simple UAV. But I see there 2 constraints.
First it's one engine plane - so you cold experience stability problems as well reliability issue.
Second is that because it's quite low cost plane you have limited possibilities for battery replacement.
So for this playing probably be better R/C plane refered as simply "Cargo". Which has two engines and is able to carry 0,5 kg of additional weight!. I recommend to upgrade engines for some more efficient A/C engines and also add some battery and of course your control unit.
There is youtube video with it... https://www.youtube.com/watch?v=ilbB72jBYT8 (think RAIDENTECH used to have it on theirs store)
Or this one - but it should be to costy for you because of need of engines etc.
Joshua -
Please clarify/retract/reword your note about needing FAA flight plan simply for using a camera, before that comment takes on a life of it's own around the forums!
I'm pretty sure a two-axis digital compass won't work on an uneven surface (i.e. any aircraft thats tilted). I think you can just use the GPS receiver's bearing output, since it would be more or less reliable enough for navigation.
--I've never worked with the SuperCub, but if your camera is pointed down the front prop shouldn't be a problem for photography. However, some HobbyZone planes use cheap five-wire servos that are incompatible with all of our autopilots (indeed, I think they're incompatible with any autopilot ever made). Check that out before buying it.
--I've also never worked with regular foam. The EasyStar uses Elastapor, which is a very tough kind of foam and is actually tougher than balsa. I don't know what kind of foam the SuperCub uses, but I suspect it's not as good.
--LiPo plus brushless is always a good idea if you can afford it. Huge weight savings and power improvements.
--Just so I understand, are you planning to have no stabilization at all, and just fly by GPS? If so, let me save you some time and money on that: you're going to crash. Also, there's no easy way to combine an FMA-copilot and GPS navigation on just one channel (the rudder). I suggest that you move to a four-channel plane, so you can put the co-pilot on ailerons and the autopilot on rudder and elevator.
-Speaking of which, it is possible (just) to do altitude hold with GPS. But it's best to use a 5Hz GPS module for that; the standard 1HZ modules don't update often enough to allow you to average data over several readings (to avoid noise) and still control the plane.
Bottom line: the choice of the SuperCub and no stabilization would complicate the project and probably won't work at all. There are loads of more appropriate platforms out there and for your budget ($800) you can do better.
Replies
This plane (I already own one for playing ;)) ). Could be good platform for simple UAV. But I see there 2 constraints.
First it's one engine plane - so you cold experience stability problems as well reliability issue.
Second is that because it's quite low cost plane you have limited possibilities for battery replacement.
So for this playing probably be better R/C plane refered as simply "Cargo". Which has two engines and is able to carry 0,5 kg of additional weight!. I recommend to upgrade engines for some more efficient A/C engines and also add some battery and of course your control unit.
There is youtube video with it... https://www.youtube.com/watch?v=ilbB72jBYT8 (think RAIDENTECH used to have it on theirs store)
Or this one - but it should be to costy for you because of need of engines etc.
Please clarify/retract/reword your note about needing FAA flight plan simply for using a camera, before that comment takes on a life of it's own around the forums!
A few quick responses:
--I've never worked with the SuperCub, but if your camera is pointed down the front prop shouldn't be a problem for photography. However, some HobbyZone planes use cheap five-wire servos that are incompatible with all of our autopilots (indeed, I think they're incompatible with any autopilot ever made). Check that out before buying it.
--I've also never worked with regular foam. The EasyStar uses Elastapor, which is a very tough kind of foam and is actually tougher than balsa. I don't know what kind of foam the SuperCub uses, but I suspect it's not as good.
--LiPo plus brushless is always a good idea if you can afford it. Huge weight savings and power improvements.
--Just so I understand, are you planning to have no stabilization at all, and just fly by GPS? If so, let me save you some time and money on that: you're going to crash. Also, there's no easy way to combine an FMA-copilot and GPS navigation on just one channel (the rudder). I suggest that you move to a four-channel plane, so you can put the co-pilot on ailerons and the autopilot on rudder and elevator.
-Speaking of which, it is possible (just) to do altitude hold with GPS. But it's best to use a 5Hz GPS module for that; the standard 1HZ modules don't update often enough to allow you to average data over several readings (to avoid noise) and still control the plane.
Bottom line: the choice of the SuperCub and no stabilization would complicate the project and probably won't work at all. There are loads of more appropriate platforms out there and for your budget ($800) you can do better.