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Old Feb 20, 2013, 09:43 PM
Registered User
United States, CA, Laguna Hills
Joined Feb 2013
13 Posts
Help!
Predator DIY build!!!

Good afternoon everyone!

I'm new to the forum so Ill give an introduction first.
I'm Brandon and located in sunny So Cal. I'm a retired Marine and I own my own business. I have been interested in RC my entire life. I have been flying for about 2 years and in the last 6 month I fly every morning depending on weather for appx 2-3 hrs.

I have had the opportunity to dabble in FPV and some large scale models and loved it!

I preface this with I have NO CAD experience.

Im in the process of designing a Predator inspired model. Not a scale model, just inspiration.

Goal of this model:
Long range FPV.
Used for HD photography and in general fun. Will be flown from a command station.
Range of appx 3-4 Hrs of flight, 40-50 miles (UHF 10W antenna thoughts? What are the laws on long range FPV?) capable of being fully fueled and still hold 15 pounds or so of electronics and video gear and have good climb rate.
Gas model. And from there open to any and all suggestions.

I will attach my current CAD design (its bad again I have no CAD experience) for you to take a look at. (It is to scale to the nearest 1/8in") I built the model with Sketchup Pro.
Wing span of 96 in.
Cord of 23in give or take. Original airfoil used was a AG35 but I made some tweaks to the underside to give better lift characteristics 5 degree AOA.

My math of a 96in wing span at 35 MPH give me appx 450Lbs. of lift. Is that right?
I was looking at 50 LBs of gas at 6lbs a gal. Would it be possible to get a 80LB plane to 35mph? Could we have a launch speed of 15mph maybe even lower? Are my numbers unrealistic.

Looking for any and all options of my project. Looking to have all pieces laser cut and most pieces covered in 1/8in Balsa for strength and durability. This is a solid basic design. I will go in as I get closer to the build date, add in retracts, flaps (looking at 3.5in flaps and ailerons?)

Sorry its very scattered I've done a lot of research however depending on where you look numbers and % chance. Thank you all for any and all help and comments!!
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Old Feb 21, 2013, 08:34 AM
The Prez....... again
kenh3497's Avatar
United States, IA, Rockwell
Joined Jul 2011
4,091 Posts
The FAA, Homeland Security and I assume several other Government entities are trying to regulate UAV operations. At this point I would do nothing. The AMA states, not an exact quote, you must have a spotter that can maintain visual contact with the aircraft at all times. Right now UAV operation is on a pretty slippery slope for us modelers.

Check out the AMA web site for more info on these proposed rulings.

Ken
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Old Feb 21, 2013, 10:38 AM
AMA 910957
EJWash1's Avatar
United States, WA, Hoodsport
Joined Mar 2008
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Quote:
Originally Posted by kenh3497 View Post
The FAA, Homeland Security and I assume several other Government entities are trying to regulate UAV operations. At this point I would do nothing. The AMA states, not an exact quote, you must have a spotter that can maintain visual contact with the aircraft at all times. Right now UAV operation is on a pretty slippery slope for us modelers.

Check out the AMA web site for more info on these proposed rulings.

Ken
VERY sound advice here Ken.

TFRs (Temporary Flight Restrictions) These areas are no-fly zones, and are being used by the Fed more and more. As you point-out, the Fed is watching, and WILL take the usual "shut it all down" approach if enough F-16s/F-18s have to be dispatched to chase FPV UAVs.

It's the sign-of-the-times, my friends.

EJWash
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Old Feb 21, 2013, 03:06 PM
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United States, UT, Farmington
Joined Aug 2011
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If you want to do this "right" you need to contact your local FAA FSDO (Flight Standards District Office). While the sUAS NPRM (Notice of Proposed Rule-Making) is not even available yet, the local FSDO will be a good contact on what you can and can't do.

You will be well outside AMA recommendations for FPV with your model. There is nothing intrinsically wrong with that AT ALL...you just need to be aware of that and interface directly with the FAA to keep it on the up and up. I'm not sure what the FSDO will ask of you. It could be anything from "not on your life" to "just send us a note when you are flying so we can issue a NOTAM (Notice to Airmen) and let other NAS users know".
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Old Feb 21, 2013, 03:19 PM
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United States, CA, Laguna Hills
Joined Feb 2013
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Thanks for the heads up I looked into the AMA pubs and found that as long as the plane is kept within VLOS Im good to fly. With proper markings LOS can be at appx 10 miles. Also the plane would be considered a large scale mole due to its weight. The amount of rules and regs. on a 55+ LB plane is intense to say the least.

With that being said the only thing AMA goes off of was weight. If I can have a fully fueled and loaded weight of less than 55Lbs the only thing I would need to do is keep a VLOS.

Ill do a partial balsa covering on the wings and go film. That would cut a few oz. Move the range down to keep it within a 5-10 mile VLOS (Can the spotter be mobile? Th) That would cut fuel to about 6lbs to give me half an hour to an hour of flight. After electronics 10lbs that leaves plenty of weight for the plane.

Im glad for the heads up on the AMA rules I could of completed this and never thought to take a look! Any other advice? What about flight design? what should be the ideal fuselage length and elevator and rudder size? With a high grane antenna could 2.4Ghz get a 10 mile range? I read on DIYDrones that its possible with the correct equipment.
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Old Feb 21, 2013, 03:30 PM
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United States, CA, Laguna Hills
Joined Feb 2013
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Quote:
Originally Posted by sirzeppu View Post
If you want to do this "right" you need to contact your local FAA FSDO (Flight Standards District Office). While the sUAS NPRM (Notice of Proposed Rule-Making) is not even available yet, the local FSDO will be a good contact on what you can and can't do.

You will be well outside AMA recommendations for FPV with your model. There is nothing intrinsically wrong with that AT ALL...you just need to be aware of that and interface directly with the FAA to keep it on the up and up. I'm not sure what the FSDO will ask of you. It could be anything from "not on your life" to "just send us a note when you are flying so we can issue a NOTAM (Notice to Airmen) and let other NAS users know".
Wow had no clue! Ill be doing some more HW on these rules If I follow AMA will I be good with FAA or should I double check FAA as well?
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Old Feb 21, 2013, 04:30 PM
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United States, WA, Hoodsport
Joined Mar 2008
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espinobj,

Just to be clear, the AMA (Academy of Model Aeronautics) is a non-profit association of/for modelers. An advocacy group for model aircraft hobbyist. Look at it as saying, "practice/operate within the rules of the Association, and if something goes wrong, we will *determine* if we can help you." They do not exist as branch of the Fed. They are our collective voice to the Fed. That's all.

As far as the FAA, sure, you can (and should) seek information from their Field Standard District Office (FSDO) but I'd bet dollars to donuts they'll have to "get back" to you.

Not trying to discourage you, just don't want to see you get into a situation that can get balled-up in a big hurry.

EJWash
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Old Feb 21, 2013, 04:42 PM
rtibbetts
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Central Florida
Joined Mar 2008
286 Posts
Go to the AMA website and read documents #550 and #560 . These spell out the AMA's position regarding FPV & Failsafe, Stabilization and Autopilot Systems.
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Old Feb 21, 2013, 04:51 PM
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United States, UT, Farmington
Joined Aug 2011
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Here's a link to your local Flight Standards District Office:

http://www.faa.gov/about/office_org/field_offices/fsdo/

EJWash is probably right...the FSDOs are understaffed and overworked. Some have better personalities than others (and are therefore easier to deal with)...but they are all extremely busy. I really wish you luck...your project sounds amazing.

One thing you may be able to do is call the faa UAS office directly:

http://www.faa.gov/about/initiatives...o_contacts.pdf
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Old Feb 21, 2013, 09:13 PM
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United States, CA, Laguna Hills
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Nice! I took a look at both and will be sure to stay well within regulations, they seem to be ok as long as you keep your weight down. I called the FSDO in Long Beach and was basically told as long as I dont have a person in it, Im not within 2 miles of an airport and I dont plan to use an airport they are ok with it. The only exception was is I planned to go above 15,000 Ft which I dont.

I have intentions to use the new APM auto pilot system, I have the old system and love it. I will fly by FPV full time and if the FPV fails we will revert to LOS flight and if comm is lost we will fail-safe to a RTL. But all that is down the road a bit. I need to finish the design before I start with the electronics. I might have a finished CAD design this weekend. Ill upload it when I finish. Its the first rough draft. Still looking for any opinions on the first design. Any takers? Im think skinned I can take it!!
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Old Feb 22, 2013, 11:55 AM
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kenh3497's Avatar
United States, IA, Rockwell
Joined Jul 2011
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I would just Google some photos of UAV's. That will give you all kinds of ideas about design.

Best of luck on your project!

Ken
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Old Feb 23, 2013, 04:55 PM
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United States, CA, Laguna Hills
Joined Feb 2013
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I think you misunderstood what I was looking for. I know what I want it to look like. However making a sturdy flight worthy plane is a different story. Ive taken a look at several other builds and I think Im on track for a good first build.
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Old Feb 23, 2013, 09:51 PM
The Prez....... again
kenh3497's Avatar
United States, IA, Rockwell
Joined Jul 2011
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Quote:
Originally Posted by espinobj View Post
I think you misunderstood what I was looking for. I know what I want it to look like. However making a sturdy flight worthy plane is a different story. Ive taken a look at several other builds and I think Im on track for a good first build.
Yup, just follow proven techniques for building model aircraft and you should be good to go.

Ken
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