Saw a link to this on the RC Advisor web site (awesome site with tons of RC info) and checked it out.

I see these two gentlemen are planning a heck of a trip with an RC airplane. I applaud their enthusiasm and willingness to take on a challenge. Reminds me of myself back on 2008.

Anyway, two problems I see with this.

1. There is no way they are going to keep their plane under AUW of 5 lbs with a target speed of 70 MPH and a flight duration of 1.5 hours.

2. I don't think they can make this plane from only foam like they want to.

Have a look and see what you think. Please let's not get into the safety thing. We can debate that for weeks on end. Let's focus on the technical aspect of this electric powered airplane. Be interesting to hear your thoughts on it.

http://www.mygeekshow.com/usatrip/

Frank

1. I can build a plane that will stay up over an hour and I can build one that will go over 70 mph, but I don't think I can get one to go over 70 mph for an hour.

2. I think this can be done. A lot can be accomplished with foam, carbon fiber and maybe a bit of spruce.

I think what they are going to need is to use a GPS auto-pilot to get the plane to a destination point where they can take over and land with LOS. They will have to designate at least 50 landing sites and hope the plane and the pilots get to each one on time. A daunting task indeed!

Took a look, didn't see any reference to keeping weight under 5 lbs or using foam, but maybe I missed it. All I saw was "cut through a hundred miles of air in less than an hour and a half", which would result in an minimum average ground speed of about 67 MPH.

Anyway, sounds ambitious, I wish them luck.

I don't think this is possible with current COTS, but with a special fuel cell I was being sold last week, it might be. Not possible with electric unless they up the weight limit.

Originally Posted by foamflyer

Took a look, didn't see any reference to keeping weight under 5 lbs or using foam, but maybe I missed it. All I saw was "cut through a hundred miles of air in less than an hour and a half", which would result in an minimum average ground speed of about 67 MPH.

Anyway, sounds ambitious, I wish them luck.

In the video, he says under 5 pounds and built from foam. And it will have two motors.

Frank

"1. There is no way they are going to keep their plane under AUW of 5 lbs with a target speed of 70 MPH and a flight duration of 1.5 hours."

Um, I have a plane made of sticks and fabric that is heavier than 5 lbs, faster than 70 MPH, and flies longer than 1.5 hours. It also carries two people and requires no license to operate. A foam plane could do this better. Although they would have to sacrifice some money for fuel, I would recommend a nice small turbine to reach their flight goals-anything electric won't cut it. Last, forget the AMA for this-cost too much (hundreds annually) given how useful it would be for them (not useful).

FWIW
under AUW of 5 lbs

How about a picture of your plane?

I was under the impression while flying RC, you must maintain visual sight of the aforementioned aircraft. I see no mention of this in their blog.

Originally Posted by Mr. foambuilder

I was under the impression while flying RC, you must maintain visual sight of the aforementioned aircraft. I see no mention of this in their blog.

Did you watch the video? They are planning to use FPV and the pilot will be a passenger in a car so VLOS is out of the question.

Getting back on topic, is their objective possble? And how can they do what they want to do with what is available today? I am thinking it is just not possible with today's technology.

I'll email Trent and link this thread so they see our thoughts and ideas.

Anyone else?

Frank

I was under the impression while flying RC, you must maintain visual sight of the aforementioned aircraft. I see no mention of this in their blog.

In keeping with the AMA's rules, yes... But I doubt the AMA would want anything to do with this operation, so these guys have nothing to worry about there. Remember that TONS of people are already flying FPV way outside LOS; it's nothing new and so far it's perfectly legal.

Like Frank said when he started this thread, though, it would be cool if a thread like this could focus on the technical aspects of the project without being hampered by safety or legal whistle-blowing.

As for the goal of flying for 1.5 hours at 70mph under five pounds.... Let's see.

We're probably looking at a carefully custom-made airframe, so no off-the-shelf EasyStars, Zephyrs, or other popular FPV planes. If we assume that this plane will require, say, 300W into the motor in flight to maintain 70mph level, then we're looking at 450Wh of usable energy in the flight batteries. That's like eleven 5000mAh 3S packs once we factor in capacity usage limits and servo/equipment draws.

At this early stage, it looks like lipos would be out of the question. 55,000mAh is a LOT of lithium, and the cruise power would still be limited to those 300W.

I think that what we are seeing is a "dream sheet" from a couple of newbies. They said as much, with one video being called newbie to expert, and it is easy to see that they were unfamiliar with a lot of equipment. It would be interesting to see what they think of the feasibility of hitting all of the targets now that they have had a year or so of research.
My personal feeling, though admittedly without much research yet, is that we are looking at a "high endurance, fast, light... pick any two" situation. Also, if they are just interested in designing a plane that can meet the 5 pound, 70 mph, 1.5 hour target then "foam only" might be a viable option. However, if they are planning on actually flying it for 3000 miles then I think they really need to go with composite.

Proton exchange membrane fuel cell
http://en.wikipedia.org/wiki/Proton_...rane_fuel_cell

The aircraft is powered by an electric hybrid system comprising of a 20KW PEM fuel cell and a 20KW Li-Po battery.
http://www.ecofriend.com/enfica-fc-s...e-records.html

I could see doing it with a 4 stroke gas engine with an alternator installed and an AUW around 12-15 lbs.

Originally Posted by Eli Lipschitz

Last, forget the AMA for this-cost too much (hundreds annually) given how useful it would be for them (not useful).

Why do you think the AMA costs "hundreds" (assuming dollars)???

Hundreds of pennies, yes.

Andy

I think the 70 mph requirement is a bit out there. For the duration they will need they should design something like the Rutan Model 76 Voyager.