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
Are you thinking red flash anti-collision light plus white strobe?
I'd ramp the red up and down rather than strobe it, helps with visual tracking, and then the white strobe covers "I'm here dummy".
(Hope to get my PPL this year).
Your link is broken for some reason
Fixed your link
Their website is fairly vague and I am not sure if that is the unit size, excluding fuel (gaseous hydrogen, or their chemical mixture). This is also why I responded to Reto saying I think it will fit. I am still waiting for a reply from the company. I do however agree that unless the fuel is much larger than the unit, it should fit. Although, I am confused, cause once again we can compare This 200watt system, with the Aeropak, aircraft specific system, and they are drastically different dimensions....
Once again, I am waiting for a response email before making a final verdict.
Why not use the Aerostack 200w instead...?
http://www.horizonfuelcell.com/#!aerostacks-200w-1kw/c10tm
Time for a bit of news.... Still waiting for a reply from Horizon Fuel Cell, however I am in current contact with company who is willing to cooperate on designing an Albatross specific mapping gimbal (flat/low profile). I am also in contact with an LED strobe manufacturer. I am trying to source a 400 lumen or brighter, adjustable timing strobe. With 400 lumens it should be visible from at least 1/2 mile away over a populated city, or 1 mile plus over less populated areas.
Since day one, a lighting system was on my mind. As a private pilot I feel that fullscale pilot safety should be #1 above all. Most, including this airframe, are generally too small to benefit from red and green nav lights. So I would like to keep the airframe visible at a reasonable distance.
Granted, a strobe system would only benefit night time operations, however Search and rescue, as well as agriculture may (someday) benefit from dawn, or night time operation.
We are also speaking too a couple investors. This is why the Kickstarter is on hold. Depending on the response from these investors, I may not go through with public funding... However, It is ready to publish at a moments notice. In other words, Stay tuned!
-Justin
Andrew, Already wrote to them regarding hydrogen cylinder use. It would best suit dual smaller tank solution.
On another note, as well as contacting Horizon Fuel Cell, I am also in contact with a flat 2-axis mapping gymbal manufacturer. This would allow a flat system capable of mounting an NEX with zoom capabilities.. With this option it is also possible to allow airframe doors to seal the airframe too and from the target.
Here's the Aeropak envelope as Reto describes it. It's a big thing and probably not leaving much space for any other payload. I'd say you'd need to scale the Albatross to 3.5-4m wingspan for such a device to be useable. Of course, if you went for the H2 cylinder, you'd have a better chance of stuffing it in the quasi-cylindrical fuselage. It might fit reasonably well with the cylinder facing rearwards and placed pretty much on the CoG, but I can't find any details on their website of dimensions - perhaps I'll write to them and ask for an envelope model.
Not to mention, Gaseous hydrogen is more easily obtainable than their special compound. Gaseous Hydrogen can be bought at most welding supply stores. I know for a fact that Praxair sells Hydrogen, as I have bought it from them by mistake once when I meant to fill Nitrogen tanks. Praxair stores are located all over the US.
Reto, thanks for bringing this to my attention! I didn't know about the Aeropak. Do you have any idea of the costs? If affordable I would like to test one in the prototype.
I assume you are talking about the 3 piece chemical pack right? Being that the chemical pack its self is the variable weight section, it would be the most important to remain under CG. This being said I think it will fit, however just off of dimensions alone, it may be tight. It would be one of those real world "lets try it and see" kind of deals. On the bright side, now that I know of these fuel cells, If I raise enough for the prototype, I will surely be trying one in this airframe as well.
Some thoughts (which I will now be emailing the company to find out); How much does it differ in weight from full to empty. I could see the chemical composition as a significant difference, but I don't think the gaseous Hydrogen will differ too much. (depending on tank pressure... Of course if they took this all the way down to liquid hydrogen, then it could differ by a lot, however the canisters would also be heavier due to the need for a vacuum separation between inner and outer container. This is common in any cryogenics.) This being said, it might be okay to mount the battery out of CG range, if it isn't changing in mass by too much. Also, the option of gaseous Hydrogen not only allows for a higher density, but I assume you could have a T fitting and run two smaller piggy-back style bottles. With an arrangement of bottles you could tailor the fit inside the airframe, as well as essentially upping your capacity.
On a side note, when the Pro model gets a little further along, and depending on financial aspects such as investors, I was planning on integrating systems and components. One of those ideas was finding a Hydrogen Fuel Cell company to work with (this was before finding out about the Aeropak). On the bright side, the Pro model has a slightly wider, and longer fuselage. Also, because it isn't fully designed yet, I still have room and time to integrate a fuel cell into the picture.
A fuel cell would be a nice alternative to LiPos or LiIons. The AEROPAK delivers 200W for many hours, which would be just fine for the Albatross. It has the dimensions of ca. 320x130x120mm. Will an AEROPAK fit in the fuselage having the variable weight (fuel) underneath the wing?
In the WanderB that concept works just fine. Note that the WanderB has a split v-tail. The UMARS changed to that design as well. The reason is to avoid conflicts with the landing parachute. With no parachute a standard inverted v-tail like the Albatross has is still preferred.
-
1
-
2
-
3
-
4
-
5
of 13 Next