Hello all,
Where to start... Well, My name is Justin, and aviation is my life. I grew up in a family with aviation in our heart and blood. Everyone in my family has been in some sort of aviation, whether it is Full scale helis, prop jobs, jets/airliners, hang gliders, or even home built aircraft. I solo'd at 18 yrs old with only 9 instructor hours, and continue to enjoy every aspect of aviation. I am currently serving in the USAF as an aircraft electrician, in order to finish my Aerospace engineering degree. (Which is not far from being complete!)
Onto the project!
The albatross UAV project came to me one night while laying in bed (so original isn't it?!). My goal was to provide a high grade, inexpensive UAV platform with unrivaled performance.
My goals?
A standard 4-6kg+ MTOW
Plenty of room for sensors, batteries, and equipment
Easy 1 hour flight times, and up to 4 hours (which is the goal... of course we can't be sure to initial flight tests)
Breakdown, and transportation ease!
Wide flight envelope
Sexy and appealing looks
Last but certainly not least, EFFICIENCY!
Airframe introduction.
The wing: The wing will have a wingspan of 3000mm, and wing area of 68.38dm^2 (in other words, 118" span, and 1060in^2). It consist of an optimized foil, and a forward swept planform. The foil is designed to ensure low stall speed, while maintaining a high max efficiency, and large cruise window. The wing planform Utilizes this foil nicely. It is a relatively high aspect wing with a ratio of 13.2. I have found that this moderate aspect ratio is preferred at RC Reynolds numbers for numerous reasons. an Aspect ratio of 12-15 allows for easier, and stronger wing structure, it allows for slightly higher Reynolds numbers, allowing airfoil's to work properly, over a wider speed range, and allows for easier built in retract, and or component bays. Obviously, we want to achieve all of the above, with minimal impact on performance. Of course a Higher AR wing would be more efficient, but at a significant cost (both in actual price, and giving up benefits.) The wing will be built with built in component bays, allowing for RC rx install in one wing, and Vtx install in the other. Not only does this allow for more room in the aircraft, but it allows for proper separation between Vtx and RC rx. The wing is forward swept, which helps minimize the chance of tip stalling while on approach with your UAV, which may as we all know, be overloaded. (there is nothing as horrible as losing your beloved UAV platform and equipment!). The downturned style tips aren't just for sex appeal, they actually reduce drag and tip vorticites, as well as decrease stall, while improving stability!
The Fuselage: The fuselage is designed around the user. It is designed to have plenty of usable storage space. Whats this mean? Well why would you have a tall narrow fuse? This not only makes is a huge PITA to work in, yet it limits how YOU want to lay out your components! The fuselage is approximately 740mm long, 150mm deep and 200mm wide. To avoid excessive fuselage/wing intersection drag and interference the fuselage is built in a slight trapezoidal shape, only to an extent that wouldn't hinder storage capacity to much. This translates into a fuselage with more usable space than the popular SkyHunter. I haven't mentioned efficiency yet. Lets not forget about that! The fuselage is actually a very efficient shape, minimizing the drag left behind. (even though it will only get chewed up by a prop...). It is also efficient in cooling. It will be designed with a NACA duct in the nose, which is a high pressure region. It will consist of an exhaust right above the motor, which is the lowest pressure region. think suck and blow. While creating a pressure differential it actually pulls air through the airframe keeping necessary components nice and cool.
Tail/s: The tail is an Inverted V design. Why? Simple really, an Inverted V improves efficiency while decreasing drag. It is also naturally more stable in a banked, and coordinated turn. The Inverted V allows for twin tail boom design, allowing for a large diameter prop. It also raises the ground clearance of the tail on landing and takeoff.
Breakdown and transportation: The number 1 reason for keeping airframes small is due to transportation and storage. The Albatross is designed to fit into a box no larger than .35m X .5m X 1m. In reality the case could be much smaller. How does it do this? The fuselage is 740mm X 200mm X 150mm, needless to say, it was designed within the required specifications. The wing is 3m long! However, it simply breaks into 3 1m long sections. The twin carbon-fiber tailbooms are 700mm each. The tail will be hinged at the center, and consist of two 440mm halves, allowing it to fold into one 440mm piece. Not only does this make it easy for the end user, but it reduce's shipping costs to your door. No more paying as much as 50% of your aircraft on shipping alone!
Goals:
My Short Term goal is to finish analysis and development. I am planning on starting a kickstarter to fund the initial molds and production costs. The current Design consists of a fiberglass fuselage, twin carbon fiber booms, and either a foam core/obeche covered wing, or an all built up wood wing. It will come with optional fuselage formers/inserts. These will be laser cut, allowing the builder the option of using them or not. These peices will consist of a retract mount (offset similar to an A-10c aircraft nose wheel, to allow for minimal effect on usable space) as well as numerous mounts and shalves for components and or batteries. Of course, as mentioned this will be up to the customer whether or not he/she will choose to install them. It also allows for some open source design in case anyone wants to improved upon, or create their own after market laser cut parts. This airframe would be available at a goal price of around $500 usd. This may or may not be achieved, but it is my GOAL. I consider this a reasonable goal considering similar aircraft such as Hobbykings UAV-3000 are capable of being produced around $300. I hope that my few added features are not enough to out-reach my goal.
Specs:
Albatross:
Wingspan; 3000mm
Wing Area; 68.38 dm^2
Root Chord; 300mm
Tip Chord; 160mm
Fuse Length; 740mm
Fuse (max) Width; 190mm
My Long Term Goal is a Albatross Pro version. The Albatross Pro will have a slightly enlarged fuselage, more wing area, higher MTOW, change in airfoil, fully molded wings and tail, and more precise construction. These changes would increase MTOW, and cruise speed/efficiency to a more specified range. It would also consist of a few ease of operation features such as built in Cannon-plug style connections for easy quick-disconnect assembly. This means that when you take off the wing, there is no servo connection to fumble with. It would also consist of some ease of assembly mods such as quick disconnect wings, booms, and tail, requiring no tools to use. (Think, Crutch/cane style push button. This would be located under the flaps.)
Specs:
Albatross Pro:
Wingspan; 3000mm
Wing Area; 75.216 dm^2
Root Chord; 330mm
Tip Chord; 185mm
Fuse Length; 890mm
Fuse (max) Width; 230mm
Here is a more in-depth design log on my RCG account. The wing planform, and laminar foil research was originally from a previous project, before I realized its potential in FPV/UAV. Although the introduction of my UAV/FPV platform is fairly new, a lot (many years worth) of prior personally research has been incorporated.
I am currently in communication with a few different OEM manufacturers for an initial Hobby version, and a long term Pro Version. If you know of, or you are another OEM manufacturer feel free to contact me! It would be much appreciated!
Please, feel free to comment, discuss, and provide constructive criticism! After all, this is my first post on DIY Drones, so please be nice!
Comments
You can illustrate your market niche by comparing your design with the competitors in a chart. I guess the most important two criteria for your airframe are price and size. You can graphically position your design and your competitors in a two dimensional chart with one axis being the price and the other being the MTOW. Then you can distinguish yourself from larger, smaller and more expensive airframes at a glance. For the airframes of similar price and size you can add another chart with the next two important criteria. You could choose efficiency, transport size or speed envelope. Like this you can make sure your airframe really falls into its own category and what distinguishes it from competitors.
Some airframes to compare with:
I am sure there are more. Keep in mind:
I like your project and hope my input helps.
It might also incorporate some laminar foils I have spent quite a bit of time developing. They are excellent in performance, however they tend to cater towards the professional side of things, higher cruise speed, longer range, etc. I find that the majority of hobby UAV enthusiasts prefer to cruise between 55km/h and 75km/h. Laminar foils are very inefficient at these speeds, however much faster and they start becoming much more efficient.
The main differences between the pro and hobby will be the following, as of now (however more changes are to come). The pro will have significantly more room in the pod, and be of complete composite construction, including wings and tails. It will incorporate complete, no tool assembly and disassembly. Rather than servo connectors it would have built in harness with cannon plug style connectors at all intersections. The wing has been increased by approximately 7dm^2. As of right now there are no plans for integrated electronics as this is not exactly my forte. However the existence of the Pro version depends on the success of the hobby version. If all goes well I will eventually some day try to source out some sort of retractable camera dome. However in my research I have found that the majority of UAV users have their own priority when it comes to components, so most likely, if anything is provided it will be minimal.
awesome well I will be supporting the project no problem. the pro version what is going to be different have you thought about fitting in a hydrogen power source or integrated electronics to set it apart by miles. could be a cool thing to do, its definitely an interesting project that looks the part
Thank you very much Jon. I have gotten a lot of support on the project, and feel it really fits a niche that hasn't been touched yet. I am hoping to build enough of a support group to fund a kick starter and get these bad boys on the market. As mentioned, the production flow chart would start with finishing the Albatross design process (it only has a few minor details left, like designing the internal braces, etc.). This would be the Hobby version. After this model is up and running, I will use these earnings to start producing the slightly larger, more capable Pro version, if the interest is still there.
This project looks like the muts nuts to me. I would love to design my own airframe. keep up the good work and keep us posted about manufacturing these ''little'' bad boys, I want one :)
Hello Reto, thanks for your reply. I am well aware of the Penguin and its price tag. This Airframe has an entirely different market. Being that my skills are not in electronic programming, I am not trying to revolutionize the world of autonomous flight, I'll leave that to the geniuses behind the computers! Instead the goal of the Albatross is to supply an affordable, and efficient airframe. An airframe that does not limit the end user in performance, or flight characteristics. This is designed for the Hobbyist in all of us. With an entry level price of <$500 for the "hobby" airframe, it will allow the masses the access to an easy to use, and efficient airframe. There are many people, including myself, that would like an efficient airframe without spending $9700 for a bare airframe (like the penguin). Also, many of us would prefer to land and take off from dirt strips, and/or normal RC fields without investing in car mounted launch systems/and or exepnsive catapults. In reailty the Penguin, Aerosonde, and other airframe's aren't anywhere near the same market I am aiming for. The hobby version will most closely fall in the same category and user base as the Techpod, however many of us prefer solid wood, or composite airframes. Also of course, being able to break down for transportation is a HUGE plus. The Pro version would fall into its own category as well. Although more expensive than the hobby version, it is still a fraction of the price of the penguin. It may not have the same MTOW, however for the price of the penguin, you can to afford to purchase multiple Albatross Pro airframes, and theoretically fly two or three of them and get the job done quicker.
To say the airframe is not important seems conterintuitive to the premesis of UAV's in the first place. The idea is to be efficient. If we quit designing efficient, airframes that meet a specific mission, then we might as well all fly dollar tree foam airframes and load them up with fancy electronics.
This particular airframe was designed to carry more than the Skyhunter, with a larger speed envelope, and more efficient cruise. It is designed to fit in a prius, to cut down on shipping and production costs of a composite/wood hybrid model, all without the expensve of efficiency. The Techpod is a seemingly great airframe, however I have no use for an airframe that takes up more room, and carries less. This is why the Albatross, in a way, falls into its own category.
As mentioned, the goal will be to roll out the Hobby version. If this version proceeds as I hope, I will eventually invest in the full molded, and slightly improved Pro airframe. It will initially come as bare airframe, or ARF aircraft (including servos, motor, esc, etc...), however It will not be supplied with any autonomous systems, as I find that the majority of people have their own preforance.
Great project. You can learn a lot designing your own airframe.
Many of your thoughts are spot on correct. Some of them are not clear to a wide range aviation enthusiats, e.g. the advantages of an inverted V-tail. The designers of Aerosonde and the Penguin found the same solution. We designed a similar airframe from scratch, the Y-UAV. Our colleagues nearby designed the UMARS.
We designed the Y-UAV for the UAV Outback Challenge. At the end we had a nice airframe but not enough time to concentrate on the more crucial parts of an UAV, like the autopilot or the long range radio link and for system integration. We did not have enough time on the field for testing, training and optimization. In the hindsight the nice airframe was not worth the effort.
The airframe is not the crucial part of an UAS. I recommend to buy it off-the-shelf whenever possible. There must be very special requirements to make a custom design pay. Think about the unique selling propositions of your airframe compared to an Aerosonde, Penguin, TechPod or AWK-21.
This type of tail is a was introduced by a polish designer, by the way! :)
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