A Dream UAV Project Becoming A Reality USER FEEDBACK NEEDED -:PLEASE LOOK:-

[ninja21m]

I will start out by thanking everyone on this forum for their wonderful advise, comments, experiences, and knowledge. I like many others have am embarking on a UAV project that will combine the best of all aspects of the hobby, while trying to accomplish the task on a non commercial budget.

After much research and looking at the different airframes available and tested by everyone out there I have decided to go the way of the military and build a scaled down Predator Drone. It seems that this design is good for longevity, payload carrying ability, and if it is good enough for the military then why can't it be good enough for me. The question still remains, " If this airframe is so good why are more modelers not using it?" If anyone has any comments on this I beg you to tell me as we have started designing the plans but are not to the point of no return on airframe design.

Our end goal is to build a UAV that has the potential for long range, 200+ miles away from base station. Have live video and telemetry sent back to our ground station so that we can monitor and have a model that is durable enough so that we can add functionality to it in the future if we decide to.
Our chosen power plant is a Zenoah G45, We feel that this engine has plenty of power so that it can fly the model at 1/4 throttle with a hope that we can get good fuel economy, and meet our goal of doing some pretty long runs without the need to dock with our model refueling station ( just joking we do not have one of these).

For telemetry we have pretty much narrowed it down to a few companies that offer the ability to overlay your flight info on top of your video using GPS information for the source of the data.
When it comes to the video downlink we have looked at all the bands, 900mhz, 2.4ghz, 5 ghz,cell phones, and I believe 1.7 ham UHF bands. There are plusses and minuses to all the different bands and I think HAM is the way to go with cost being low, range being high, and power consumption being all but nothing. A technical license is required but let that be the least of our worries.
As far as auto pilots go we are still undecided. We have looked at the picopilot models and note that they have some good features but also carry a heavy price tag. We have looked high and low for a Microsoft windows based system flight controller as a small micro ITX computer could run everything in one box but I have not found a controller that someone has made to suit this purpose. I am hoping that this post will bring some recommendations on the best type of auto pilot we should be using for our project.

I have a pretty good idea that with all the collective knowledge on this forum each question will open up a new area that sprout a forest of questions and details that a project like this requires. I plan on documenting the entire project on a website and also on this forum for the purpose that knowledge should be free and if someone can learn something from what I have done, then I will sleep well that night.


Here's to a project that will hopefully be fun and successful.


James



Let the questions and advise begin !!!

[macboffin]

The Predator is effectively a large powered glider, the long wings,(High Aspect Ratio) resulting in low cruise drag and thus endurance on modest fuel amount. Stability will be an issue, especially in pitch, since the higher the aspect ratio the narrower the band of usable angle of attack, ie the higher the AR, the easier to stall.They do not roll/turn too well either, due to the inertia of that long wing. Which will be heavier than a shorter broader wing since you have a shallower main spar extending further from the root.
One advantage of a high aspect ratio large area wing is altitude ability, you will see if you research that high altitude aircraft have high aspect ratios, unless like the "Blackbird" they are squirting along quick enough to stay up there in very thin air.Of course you will presumably not be operating at altitude if you are in the States.Das ist verboten! Which leads to the question, what area are you proposing to fly in? Somewhere remote with no other air traffic? As to frequency, you will need a fair bit of bandwidth.
I could go on for a long while but I guess others will also be commenting on various aspects of your project.Wish you luck!

[ninja21m]

The Predator is effectively a large powered glider, the long wings,(High Aspect Ratio) resulting in low cruise drag and thus endurance on modest fuel amount. Stability will be an issue, especially in pitch, since the higher the aspect ratio the narrower the band of usable angle of attack, ie the higher the AR, the easier to stall.They do not roll/turn too well either, due to the inertia of that long wing. Which will be heavier than a shorter broader wing since you have a shallower main spar extending further from the root.
One advantage of a high aspect ratio large area wing is altitude ability, you will see if you research that high altitude aircraft have high aspect ratios, unless like the "Blackbird" they are squirting along quick enough to stay up there in very thin air.Of course you will presumably not be operating at altitude if you are in the States.Das ist verboten! Which leads to the question, what area are you proposing to fly in? Somewhere remote with no other air traffic? As to frequency, you will need a fair bit of bandwidth.
I could go on for a long while but I guess others will also be commenting on various aspects of your project.Wish you luck!


Thank you for your input, feel free to go on and on and on as I think a lot of people will be using this post as source of projects they might wish to build. I understand what are talking about as per the high aspect with, but due to the fact that we are not going to be flying it for fun doing loops and such do you think this airframe will do what it needs to do? My goal was to have a wing that could lift the payload with out needing constant power thus depleting fuel reserves.

And yes at first it will be flown at a R/C field to test the airframe, but what it goes on autopilot it will be flown in a very vacant land until we can put a transponder in it and file flight plans.
You are correct that we will need bandwidth, I just wish satellite was available as it is for the real predator. Oh well I will make due.

Thanks again.

James