For the antenna, how about in the gear doors? When extended and on the ground, better for landing and taking off. When up, better for signals at altitude. Just a thought since the whole plane is a ground plane for the antenna.
I rarely jump on a video this quickly! You guys rock and truly make me want to get a license so I can build and fly the DarkAero 1! Thanks for sharing the whole build process - I have binged the whole library.
I installed an Airmaster prop years ago and it was very simple to integrated it. Couple of power wires to the controller and then to the prop. Made flying with a Rotax 914 very relaxed. Pick the right flight regime and off you go, simple as that. Manifold pressure is then you main indication of power.
At McDonnell Douglas, we embedded antennas in the DC-9 like this as far back as the early 1960's for VHF and low freq ADF. aka CONFORMAL antennas in the vertical and WBF and the tailcone.
Multiple antennas have always required about 2 ft. of separation to avoid interference and cross talk. I hope that new antenna works out. Please provide a link for the paper.
I love your work! Two thoughts on the antenna. First, that design looks like it could work fine, but the meter isn't telling you the performance. It's telling you the impedance, which is how it loads the radio. That's important, but it doesn't tell you how well it works as an antenna. You'll want a field strength meter for that, or even a simple test where you transmit with that compared with a standard antenna, listening from a distance, preferably with some sort of meter. But maybe more important - if that antenna is going to be connected to a full size radio, and it's on the canopy, it may be way too close to the passenger's head. On a traditional metal plane, the skin protects the occupants from high RF. With a composite, you need to move the antenna farther away from people, especially their heads. With a 1W handheld, maybe not a big deal, but with a 25 Watt radio, it's kind of a big deal. Best of luck!
The antenna design itself might not be a problem... but considering the whole composite carbon fiber body will be coated with metallic painting for discharging when flying. The flat antenna might have certain interference.
Excellent video and more great progress. I think you guys deserve extra credit for this one. Go ahead and add another three green bars to your progress tracking spreadsheet.
Hoping to see a performance comparison at some point between the Airmaster and a fixed or ground adjustable prop. I have no doubt the Airmaster will be at least slightly higher performance, but it would be cool to see exactly how much of a difference it makes, especially given the cost and weight difference between the two (30ish lbs and ~$9k vs 8ish lbs and ~$3k).
On a nice cold crisp day it should work amazingly well. Especially if there is ducting. It also depends of your PRF. The we have Lobbing, Ranging and Aspect Dependency. I used to be an Electronic Warfare Operator on P-3C Orion's in the Navy for two years. And I was an Air Traffic Controller for 9 years. (I got airsick a lot so I had to change Rates).
@@DarkAeroInc They also don't necessarily like the word "ham." You will probably find something interesting in the ARRL Antenna Handbook. www.arrl.org/arrl-handbook-2020 there is another publication called "Antenna Book," too. Can't hurt.
I'm very interested in your Airmaster Propellor installation, as it may apply to my UL520iS in my Cozy Mk. IV project. I have contacted Airmaster, and they do have a controller/propeller package for my engine and plane combination. That makes me happy! I look forward to further updates your project!
Antenna design is chock full of entertaining and unexpected failure modes. Not sure I'd want to spend valuable time on that. What might help with space is re-using parts of the CF or the alu honeycomb as a ground plane for a regular antenna. Also lining parts of the cockpit with some thin sheets of alu coated mylar or similar to provide an RF shield so the antenna doesnt radiate into headsets and the like. Also using differential signalling and scattering some RF chokes between any electrical components will stop RF energy coupling into important stuff.
As far as I know, radio waves used in aviation are polarized to avoid interference most commonly between COM and NAV frequencies, thus the orientation of the antenna counts a lot. At 2:45 you are saying that this antenna is designed for COM frequencies, but for me it seams that it is aligned with the NAV frequency polarization. I'm not an expert on EM, so please correct me if I'm wrong.
The com radio frequencies are vertically polarized, which was a big part of the challenge with this antenna since we have limited vertical space in the turtleback of the airframe for the antenna to "see" out of. The antenna is slightly curved so there is some component of it in the horizontal axis but the majority of it is in the vertical axis. More real-world testing will be needed to see whether or not this antenna solution will work, but we'll report back how this goes.
@@DarkAeroInc I am actually in a home building project myself, and I am planning to embed the COM antenna into the vertical fin, and make it possible to install NAV antennas into the horizontal fin. Your team and your videojournal is really inspiring. I would love to here your thoughts on this idea.
That's an awesome setup, I flew it on the Sling TSI... one option has Beta instead of Feather, how cool would that be? yeah, Feather is for safety but Beta is cooler
Sherif, the radio we interface with the antenna is designed for the civil air traffic control frequency band (118.000 to 136.975 MHz), which limits the antenna to this bandwidth. The Garmin radio requires that our antenna hit what is called a Voltage Standing Wave Ratio of 3:1, but ideally 2:1 for this frequency band. The vector network analyzer being used in the video allows us to check this performance metric to see what we can do to achieve this ratio before using it with the radio in flight.
Love the plane can’t wait to see her fly!! Also think it’s cool y’all are from Wisconsin. But one question on my plane I’m building I’m planning to run airmaster prop But I can’t get ahold of anyone. Is there a dealer near here to order one? I’m two hours north of you.
Airmaster propellor is in New Zealand. I got a quick e-mail response from them by using the Contact page on their web site. www.propellor.com/ContactUs
You mentioned in a previous video that you were using Onshape for your CAD work. I noticed Fusion 360 for the milling work. Are you using Fusion 360 just for CAM?
The radios have a lot of output power (16W!). Needs to be far away from you and other electronic equipment. If they radiate into the cabin you will get feedback because they will couple into the mic of the headset.
The mismatch between vert and horizontal polarization is about 3db. That much "bend" shouldn't cause a problem. The FCC has come out with new RF exposure limits. With the antenna so close to the crew compartment you may want to look into projected field strength, before you finalize the design. Also consider putting one antenna on the top, and one on the bottom. Use the top one on the ground, for ground, tower, atis. Use the bottom one in flight.
@@linuxranch The loss is cos^2 of the angle. At 90 degree mismatch, no energy is transferred. Which formula shows only 3 db loss at total mismatch of polarization?
OK, you show a pic of the com antenna but fail to explain the custom antenna design which you claim is a lot of work. There are a number of designs that will work, you design, build, install and then check the resonant frequency which will end up being different from the design formula due to the dielectric constant of your carbon fiber. You the work backwards to find a correction and apply that to the original design.
Thanks for the request. We just updated the description of the video to have the link, but the source for the research can be found here: www.jpier.org/PIERM/pierm78/11.18102701.pdf
Have you guys thought about putting out a publicly traded stock? I feel like thatd add some nice funding and us av geeks a good way to make money when this company blows up in a good way!
Great avgeek stuff!! Thanks for posting.
Thank you and thanks for watching!
Oh man, I hope you are the test pilot for this program... and document it, and publish it!! :)
You should do a collab with Mike Patey!!!, it would be really cool and would bring many more people your way!!!
That would be epic!!!
I can tell you who NOT to do a collab with - something about a raptor. I still think that guy may end up killing himself.
For the antenna, how about in the gear doors? When extended and on the ground, better for landing and taking off. When up, better for signals at altitude. Just a thought since the whole plane is a ground plane for the antenna.
I rarely jump on a video this quickly! You guys rock and truly make me want to get a license so I can build and fly the DarkAero 1! Thanks for sharing the whole build process - I have binged the whole library.
Mads, thanks for following along! We'll keep the updates coming.
I installed an Airmaster prop years ago and it was very simple to integrated it. Couple of power wires to the controller and then to the prop. Made flying with a Rotax 914 very relaxed. Pick the right flight regime and off you go, simple as that. Manifold pressure is then you main indication of power.
At McDonnell Douglas, we embedded antennas in the DC-9 like this as far back as the early 1960's for VHF and low freq ADF. aka CONFORMAL antennas in the vertical and WBF and the tailcone.
Multiple antennas have always required about 2 ft. of separation to avoid interference and cross talk. I hope that new antenna works out. Please provide a link for the paper.
I love your work! Two thoughts on the antenna. First, that design looks like it could work fine, but the meter isn't telling you the performance. It's telling you the impedance, which is how it loads the radio. That's important, but it doesn't tell you how well it works as an antenna. You'll want a field strength meter for that, or even a simple test where you transmit with that compared with a standard antenna, listening from a distance, preferably with some sort of meter. But maybe more important - if that antenna is going to be connected to a full size radio, and it's on the canopy, it may be way too close to the passenger's head. On a traditional metal plane, the skin protects the occupants from high RF. With a composite, you need to move the antenna farther away from people, especially their heads. With a 1W handheld, maybe not a big deal, but with a 25 Watt radio, it's kind of a big deal. Best of luck!
I've been addicted to your videos for the last few days: If Bitcoin really pops off in the next couple years you can put me on your customer list!
The antenna design itself might not be a problem... but considering the whole composite carbon fiber body will be coated with metallic painting for discharging when flying. The flat antenna might have certain interference.
Alec Wild used the same prop hub(s) & control(s) on his DoubleEnder. You could check with him for insights. Keep up the good work!
Excellent video and more great progress. I think you guys deserve extra credit for this one. Go ahead and add another three green bars to your progress tracking spreadsheet.
Hoping to see a performance comparison at some point between the Airmaster and a fixed or ground adjustable prop. I have no doubt the Airmaster will be at least slightly higher performance, but it would be cool to see exactly how much of a difference it makes, especially given the cost and weight difference between the two (30ish lbs and ~$9k vs 8ish lbs and ~$3k).
On a nice cold crisp day it should work amazingly well. Especially if there is ducting. It also depends of your PRF. The we have Lobbing, Ranging and Aspect Dependency. I used to be an Electronic Warfare Operator on P-3C Orion's in the Navy for two years. And I was an Air Traffic Controller for 9 years. (I got airsick a lot so I had to change Rates).
You know what looks really good on an VNA?
A well constructed dummy-load
Reach out to the local ham radio community. Those guys love to help out and they have spent years in the dark art of antenna design.
Jay, thank you for watching and the suggestion! We will check them out.
@@DarkAeroInc or Mike Patey ha ha, damn sure he'll love what you guys are doing!
@@DarkAeroInc They also don't necessarily like the word "ham." You will probably find something interesting in the ARRL Antenna Handbook. www.arrl.org/arrl-handbook-2020 there is another publication called "Antenna Book," too. Can't hurt.
What field of view do you want in your comm antennas? Also do you have a link for the VNA you are using for the antenna testing?
I'm very interested in your Airmaster Propellor installation, as it may apply to my UL520iS in my Cozy Mk. IV project. I have contacted Airmaster, and they do have a controller/propeller package for my engine and plane combination. That makes me happy! I look forward to further updates your project!
Antenna design is chock full of entertaining and unexpected failure modes. Not sure I'd want to spend valuable time on that. What might help with space is re-using parts of the CF or the alu honeycomb as a ground plane for a regular antenna. Also lining parts of the cockpit with some thin sheets of alu coated mylar or similar to provide an RF shield so the antenna doesnt radiate into headsets and the like. Also using differential signalling and scattering some RF chokes between any electrical components will stop RF energy coupling into important stuff.
As far as I know, radio waves used in aviation are polarized to avoid interference most commonly between COM and NAV frequencies, thus the orientation of the antenna counts a lot. At 2:45 you are saying that this antenna is designed for COM frequencies, but for me it seams that it is aligned with the NAV frequency polarization. I'm not an expert on EM, so please correct me if I'm wrong.
The com radio frequencies are vertically polarized, which was a big part of the challenge with this antenna since we have limited vertical space in the turtleback of the airframe for the antenna to "see" out of. The antenna is slightly curved so there is some component of it in the horizontal axis but the majority of it is in the vertical axis. More real-world testing will be needed to see whether or not this antenna solution will work, but we'll report back how this goes.
@@DarkAeroInc I am actually in a home building project myself, and I am planning to embed the COM antenna into the vertical fin, and make it possible to install NAV antennas into the horizontal fin. Your team and your videojournal is really inspiring. I would love to here your thoughts on this idea.
That's an awesome setup, I flew it on the Sling TSI... one option has Beta instead of Feather, how cool would that be? yeah, Feather is for safety but Beta is cooler
Looks really well thought out. Are you doing any fatigue tests on the wing or are they unnecessary?
most probably unnecessary as carbon is very good also in dynamic loads. Check out the Wöhler curve for carbon..
tuned in for the antenna info. Not enough juice for the squeeze there.
i have enjoyed other videos though.
Did you use the deflection testing to verify that pushrods have adequate clearance and are free from binding at max anticipated loads?
Hello, the link to the antenna paper is broken, if you could please post a new one? Thanks!
Awesome update, do you guys have to get FCC certifications if you use a custom antenna? How do you work with the radio manufacturer to approve it?
Sherif, the radio we interface with the antenna is designed for the civil air traffic control frequency band (118.000 to 136.975 MHz), which limits the antenna to this bandwidth. The Garmin radio requires that our antenna hit what is called a Voltage Standing Wave Ratio of 3:1, but ideally 2:1 for this frequency band. The vector network analyzer being used in the video allows us to check this performance metric to see what we can do to achieve this ratio before using it with the radio in flight.
You don’t require FCC certification for an antenna. However the transceiver and total EIRP has to meet both FCC and FAA rules.
Love the plane can’t wait to see her fly!! Also think it’s cool y’all are from Wisconsin. But one question on my plane I’m building I’m planning to run airmaster prop
But I can’t get ahold of anyone. Is there a dealer near here to order one? I’m two hours north of you.
Airmaster propellor is in New Zealand. I got a quick e-mail response from them by using the Contact page on their web site. www.propellor.com/ContactUs
What's the purpose of painting the test fixture?
You mentioned in a previous video that you were using Onshape for your CAD work. I noticed Fusion 360 for the milling work. Are you using Fusion 360 just for CAM?
That's correct. We use Onshape for all of our design work. Fusion 360 is our current CAM tool.
You have talked a lot about design choices. How about side by side seating opposed to inline seating for speed?
The radios have a lot of output power (16W!). Needs to be far away from you and other electronic equipment. If they radiate into the cabin you will get feedback because they will couple into the mic of the headset.
Also, the antenna needs to be vertical (for the correct polarization) otherwise you will loose a lot of RF energy both for Rx and Tx.
The mismatch between vert and horizontal polarization is about 3db. That much "bend" shouldn't cause a problem.
The FCC has come out with new RF exposure limits. With the antenna so close to the crew compartment you may want to look into projected field strength, before you finalize the design.
Also consider putting one antenna on the top, and one on the bottom.
Use the top one on the ground, for ground, tower, atis. Use the bottom one in flight.
@@linuxranch The loss is cos^2 of the angle. At 90 degree mismatch, no energy is transferred. Which formula shows only 3 db loss at total mismatch of polarization?
this sys looks like a whirlwind propeller from san diego callifornia, 👍
Why doesn't Aviation like yourselves use concentric twisting in your wiring harnesses?
OK, you show a pic of the com antenna but fail to explain the custom antenna design which you claim is a lot of work. There are a number of designs that will work, you design, build, install and then check the resonant frequency which will end up being different from the design formula due to the dielectric constant of your carbon fiber. You the work backwards to find a correction and apply that to the original design.
What vector network analyzer did you use?
The NanoVNA: nanovna.com/
Any progress with your custom antenna?
If lightning strikes, won’t that evaporate the copperfoil antenna?
It's hard to say what might happen to the antenna in the event of a lightning strike as we have not collected data on this.
Can you share the link to the paper with the design for the antenna?
Thanks for the request. We just updated the description of the video to have the link, but the source for the research can be found here: www.jpier.org/PIERM/pierm78/11.18102701.pdf
The most out of place object in your lab is that DIN module box with a so typically european cabling inside :)
Adel clamps=P-clip
They really need to use aviation lingo for those. No such thing as a P-clip.
You all guys looks same .
Have you guys thought about putting out a publicly traded stock? I feel like thatd add some nice funding and us av geeks a good way to make money when this company blows up in a good way!
WTH is this
No faith in electric prop controllers. I'm sure you'll come back to a historically tried and true real aircraft prop during your flight testing.