Just thinking out loud here a bit, but as I was reading through the LEAP thread and catching up on Ifly's "challenge" and V-22's digital project I was reminded of an old saying we had when I was in the aviation business.  Most of my 31+ years was in Quality and we used to have a saying that went something like this...

"Quality, Cost, Schedule.  Pick two, cuz you can't have all three."  The point being you could achieve any two of the objectives but all three was really, really tough.  That led me to this rather crazy idea.  For the sake of argument stay with me here, even if my numbers are off as I'm just using them to get the principal of the idea out there.  

In Ifly's thread his challenge includes three objectives:

1. AUW of <250 grams
2. Flight time of 30-31 minutes
3. Flight Distance of 10Km total.  (LEAP is 20Km.)



Given these restrictions I kept on thinking that getting two of them might be possible but all three???....Tough stuff!  But then I kept coming back to power.  Battery power.  With enough battery you can get 30+ minutes of flight time.  With enough battery you can get 10Km or more.  But that third piece...ouch.  How do you get that kind of time and distance and still be under 250g?  That is the primary piece of technology that might not quite be there just yet.  

But what if you could start out with a quad that is wired with two batteries on a switch of sorts, such that only one battery is "active" at a time.  That first battery, powering the quad with both batteries attached, can get you say 40% of your distance goal due to the additional weight.  

Then as you approach the 40% you hit a switch that does two things.  One, it switches power to the fresh battery and two it releases (ejects?) the first battery.  The first battery falls to the ground via a simple light weight parachute (maybe with a tiny gps tracker?) while the second battery, now with a lot less weight to provide power for, can do 60% of the distance goal.  

I know it sounds outlandish and you'd still have to account for the extra weight of a 2nd battery, as well as the switch and ejection system.  Both of which would challenge the 250g limit, but it's not unlike the original solution for getting a man to the moon.  You consider the first battery to be the "booster-rocket".  The intent would be to eject and recover it which offers it's own challenges, but again I'm just trying to think outside the box a bit.

Would it be considered "cheating" to use something like this?

Ive thought a little about this concept too. My take is:

If the ejected battery is done in a controlled manner and recovered I'd consider it an execution of a planned flight and not cheating.

If it's a controlled ejection but not recovered I'd consider that a failed flight.

If it's not a controlled ejection or recoverable I'd consider that failed planning. Id think this scenario is cheating and generally not an acceptable practice.

Hi Skavage,

Quote from your post:
__________________________________________________________________________________________________
"Quality, Cost, Schedule.  Pick two, cuz you can't have all three."  The point being you could achieve any two of the objectives but all three was really, really tough.  That led me to this rather crazy idea.  For the sake of argument stay with me here, even if my numbers are off as I'm just using them to get the principal of the idea out there.  

In Ifly's thread his challenge includes three objectives:

1. AUW of <250 grams
2. Flight time of 30-31 minutes
3. Flight Distance of 10Km total.  (LEAP is 20Km.)
__________________________________________________________________________________________________

Here is the thing. It has already been done commercially:  DJI Mini2 at DJI,    DJI Mavic 2 Best Drone for Beginners

The challenge is NOT whether it can be done ; 
The challenge is to see if one of us can build a quad that matches the DJI Mavic Mini 2 performance metrics. 

The criteria was take precisely from the operational DJI Mavic Mini. 

In fact, that is precisely what V-22 had in mind with his 3" 250g 10km DJI Digital Build. The rest of us just sort of jumped on the band wagon. For me, it is in line where where I have always been except for the 10k distance. 

That said, I totally agree that any 2 out of the 3 is quite workable. Actually, once you hit the 30 minute Fly Time, then you already have a good chance at making the 10K. By using just enough throttle to maintain about 20mph you should make it; at least theoretically. 

With my Phantom-X, I have already had a flight that lasted over 21 minutes  using 2S 18650 3000 mAh batteries with an AUW of 226 grams, but this was untuned and not even checking for LVC or any other lower battery limiting elements. However, this build was not set up for long range...so...now, I am upgrading her with GPS, R9MM receiver, and watching the weight while re-assembling. 

The Quest250-LR, on the other hand, is being designed from the ground up to meet this challenge.

Any one else want to join the "challenge"     If so, start a Build thread and let me know. I will add it to the list. 

I think double battery is great idea.
Especially if first one is used to gain kinetic and pitential energy (height).

But if its just straight line.. why not focus on making frame aerodynamic. Maybe even turn arms into little wings. I can easily imagine +20% flight distance.

Booster battery with secondary onboard??  Now this is getting interesting!!  You guys are awesome!!  Liked and subscribed!!  

(27-Jan-2021, 06:27 PM)romangpro Wrote: I think double battery is great idea.
Especially if first one is used to gain kinetic and pitential energy (height).

But if its just straight line.. why not focus on making frame aerodynamic. Maybe even turn arms into little wings. I can easily imagine +20% flight distance.

Hi Roman,

Why not just build a wing?  Or a VTOL craft where 2 of the motors swiveled to a horizontal plane for forward thrust?

While these are all very interesting concepts, keep in mind this is a sub-250 gram quad. At the very least you will need some type of servo or maybe two. How much is all the extra stuff going to weigh    Nothing is free.
Another minor consideration is how much battery energy will be need to effectively disconnect and eject one of the batteries 

The issue that I see with ejecting a battery is that the connectors are pretty strong and it would take some force to disconnect. On the other hand, a very "loose" connector could be used, but then you have an electrical connection that could be flakey. Or maybe an electromagnetic connector, but that would take energy from the battery to maintain the connection.
The devil is in the details.

However, the "Mission is Yours" should you choose to accept it 

Check this out:

@Ifly - I think I better understand now where the challenge came from. That's precisely why I posed the question asking if this was "cheating". While it may or may not, in my mind things like this are always a matter intent and I think you explained that intent well.

The only thing I am left wondering is why is it so difficult for the likes of us, if DJI has already done it? Wouldn't it simply be a matter of copying their configuration in terms of components? Or do we simply not have the same things available to us? Again, I'm asking only because I don't know the background/history. Looking at the DJI spec sheet you posted I am almost inclined to think I need to go find someone's broken (i.e. - cheap) used Mavic and do a teardown of it.

I almost have to wonder if they simply did what we used to to eons ago in fixed wing. We built out of balsawood mostly and you either built your plane to fly (light) or you built it to crash (heavy/sturdy). Fly was way more fun for aero but you'd be more apt to watch a spar break and fold a wing than the guys that built theirs like tanks.

All that said, I still kind of like the thought of carrying extra battery power and ejecting after it's spent. Not so much as part of the challenge but as another new thing to do to turn shorter flight time/distance into longer ones. It's probably already been done, but it sure would be different than the norm.

I posted some thoughts on the Mini 2 here: https://intofpv.com/t-new-to-intofpv?pid...#pid124637

It should actually be fairly straightforward to match that performance with a 4"-5" build on 2S. My calculations for a 4" build are here: https://intofpv.com/t-new-to-intofpv?pid...#pid124669

I decided to try a 3" build with a heavier digital system for the added challenge. The downside is the major hit in efficiency you get going from a 4" prop to a 3" prop, and because of that it almost certainly has to be 3S, which makes things even heavier.

Good stuff V-22! Going to go read through the rest of the post.

(27-Jan-2021, 11:01 PM)Skavage Wrote: @Ifly - I think I better understand now where the challenge came from.  That's precisely why I posed the question asking if this was "cheating".  While it may or may not, in my mind things like this are always a matter intent and I think you explained that intent well.  

In my opinion, ejecting a battery is NOT cheating.  As long as the AUW on take off is less than 250 grams, it flies for 30 minutes, and will travel 10k total distance; it doesn't matter if you eject a battery or not. For this challenge, there is no specification as to distance from the transmitter, it is just total distance traveled. Flying in a big circle demonstrates the same thing. On the other hand, that won't get you a Long Distance badge because that is different; has to be 5K away from the transmitter. Hopefully, you can get it back, but that also is NOT a requirement for the badge.

The only thing I am left wondering is why is it so difficult for the likes of us, if DJI has already done it?  Wouldn't it simply be a matter of copying their configuration in terms of components?  Or do we simply not have the same things available to us?  Again, I'm asking only because I don't know the background/history.  Looking at the DJI spec sheet you posted I am almost inclined to think I need to go find someone's broken (i.e. - cheap) used Mavic and do a teardown of it.  

I have just reviewed the DJI Mavic Mini 2 specifications and watched several teardown and repair videos. I have also researched buying spare parts. Here is my take on it. First, we do NOT have the same parts {unless we buy DJI Mavic Mini 2 spare parts}. All of the housing components such as the fuselage body and arms appear to be very thing, light weight, molded plastic. Next, the motors and props look like special light weight units. In fact, the motors look a little small to spin the 4.7 inch {yeah, almost 5 inch} props. The FC board is a very small, compact, AIO board. Finally, the battery may, in fact, be custom manufactured just for them.

Although, I do believe it would be cheating to just by a set of DJI Mavic Mini 2 arms complete with motors and props, maybe their battery, and attach this to a fabricated plastic frame. That would just be making a Mini2 from spare parts. Yeah, THAT Would be Cheating. 

I almost have to wonder if they simply did what we used to to eons ago in fixed wing.  We built out of balsawood mostly and you either built your plane to fly (light) or you built it to crash (heavy/sturdy).  Fly was way more fun for aero but you'd be more apt to watch a spar break and fold a wing than the guys that built theirs like tanks.

Here is the thing. DJI built the craft to fly and NOT be able to crash. This thing has stabilizers, object avoidance, operator restriction, and almost autopilot. From what I have seen, you can turn loose of the controller and the thing still will not crash; it just holds its position until you take over control. I think their software is designed to get the quad down safely unless, of course, you have a total battery failure at altitude and drop onto hard pavement. In this case you repair it, have it repaired, or just cry. 

In fact, it might just be one of the best, all round, drones for pilots who just want to cruise around and take excellent video. No fuss, No muss, just 450 US dollars for the drone; about 630 dollars for a complete kit. It just doesn't do Acro or give you that adrenaline rush.
NO Balls-To-The-Wall flying. 

All that said, I still kind of like the thought of carrying extra battery power and ejecting after it's spent.  Not so much as part of the challenge but as another new thing to do to turn shorter flight time/distance into longer ones.  It's probably already been done, but it sure would be different than the norm.

Hi Skavage, 

So, if you want to build something that meets the criteria and ejects a battery; I say GO FOR IT  

Also, I have never seen it done before. Not to say it hasn't, just saying I can't find it anywhere. You would be breaking new ground.

One reason that I am going to try 5 inch props is because the DJI Mavic Mini 2 props are 4.7 inches which is closer to 5 inch than 4 inch.
Yeah, it looks like they are spinning them with smallish light weight motors. I believe this is where they cut out a lot of weight.

Anyway... jump on in.  See what you can do.  Eject a battery if you want to. Personally, that would be interesting.   

If there is anyone who want to get into the challenge or has a build that is similar, PLEASE add it to this thread and I will put it in the list.

(29-Jan-2021, 05:06 PM)iFly4rotors Wrote: If there is anyone who want to get into the challenge or has a build that is similar, PLEASE add it to this thread and I will put it in the list.

Hey ifly, what exactly is the “challenge”??
1) Is it to get the 5k badge?
2) Is it to beat the maverick mini? (Sub 250 and 31 minutes)
3) Is it to go the longest time (or in our case distance)??
4) or to do everything (+5k distance, +30 minute and sub 250)
Is sub 250 a requirement??
I’m interested... (I’m sorry I didn’t know... )

(29-Jan-2021, 05:20 PM)Joshua_A Wrote:  Hey ifly, what exactly is the “challenge”??
1) Is it to get the 5k badge?
2) Is it to beat the maverick mini? (Sub 250 and 31 minutes)
3) Is it to go the longest time (or in our case distance)??
4) or to do everything (+5k distance, +30 minute and sub 250)
Is sub 250 a requirement??
I’m interested... (I’m sorry I didn’t know... )

Hi Joshua,

Yes, the goal is to meet the DJI Mavic Mini 2 reported performance metrics:

1) Sub 250 gram AUW take off weight including the battery.
2) 30 minute Fly Time.
3) 10K Total Distance.

There is NO size criteria and NO specific performance metrics except the two listed.
Although the reality is that a 2 inch probably doesn't have the thrust and a 7 inch will just weigh too much.
So, it will likely be somewhere in between. My guess is 4 inch, but it could be a 3 inch or 5 inch. 

Sorry that there is not a badge. This is more of an informal challenge just to see if we can do it.

On the other hand, if you fly 5K away from the transmitter {launch location} and hopefully back, you will get an IntoFPV Long Range, 5K, badge. Just be sure that you have video to prove it. 

By the way, I have already listed your LEAP 4" Long Range Project as being in the challenge since your criteria matches except that you want to get 20K total distance. If you meet your criteria, then you will meet the challenge criteria. You have the quad, now it is about flying, testing, and getting video to support your progress and success. 

You are in the Game.       

If anything, this is a testament to DJI tech. I can't stand DJI ... but man, their tech is Tony Stark level 100 stuff.

(29-Jan-2021, 06:30 PM)the.ronin Wrote: If anything, this is a testament to DJI tech.  I can't stand DJI ... but man, their tech is Tony Stark level 100 stuff.

Hi Ronin,

Yes, I agree, this is definitely a testament to DJI technology; from what I can tell, they have designed and engineered ultra light components for the amount of power and features. Plus, they stuff all that into a light weight molded plastic shell. Whether we like it or not, the DJI Mavic Mini 2 is very likely the best all round quad on the market for cruising around and taking good video; especially if you are not into building, but rather just flying. 

Sure, it won't do Acro stunts and such...and... we say it costs a lot. Well it is on the high side, sort of, compared to what we build, but then we are not building the same thing exactly. Plus, if you are going to buy the parts and build it, why not just buy it and be done. I did think that the compact, complete all in one controller is pretty slick. It seems to everything on one board. {here's a thought, why not just buy that board rather than a "canned" DJI Air unit}. Furthermore, I don't think we can buy just the motors and props; you have to buy whole arms.

Anyway, just sayin' 

Buy the way, I have listed your Diatone Roma F4 LR build as being in the "Challenge" since it appears to fit; hope that is OK. If not, let me know and I will move it to the similar builds list.