Just a note; the Flywoo Explorer only has an AUW less than 250g with the smaller 4s 650mAh batteries; very much larger battery pack pushes the AUW over 250 grams. That 4s 18650 pack alone weighs about 185 grams (or more). So, with the Explorer's dry weight of about 163g, the AUW with the 4s 18650 pack is about 348 grams.

So, I will try a 3s 18650 setup (( yeah, it will then be over 250g, but let's see what it does. )).

{the dry weight of the Phantom-X with the 2s 18650 holder attached is 133 grams}

{2020-09-01}

Well...I decided to use a 3 cell 18650 holder instead of an "add on" to the 2 cell. This arrangement actually worked out quite well and was likely faster to put together; simply solder the wires, drill two holes, mount it, and DONE 

Aerodynamics never was a concern with multi-rotors...

{2020-09-02}  about 12:30 pm

I got to take the Phantom-X out today with the 3s 18650 battery setup. Although the flight lasted 17 minutes and 20 seconds, that was a disappointment for me. I was expecting this 3s setup to outperform the previously installed 2s 18650 setup which ran for over 21 minutes. My guess is that it took more to pull the extra weight of the 3rd battery. For me, this is the point of diminishing returns. I will try one more flight with the 3s setup, but will likely go back using LiPo batteries and try to better the 21 minute time set by the 2s 18650 pack.

found out something interesting (to me) today....the dji mavic mini uses 2s 2400mah battery and gets 30min of flight time. it's also 249g

found a teardown here https://www.rcgeeks.co.uk/blogs/news/dji...ats-inside

So your 21min isn't bad at all

(12-Sep-2020, 11:37 PM)TStroFPV Wrote: found out something interesting (to me) today....the dji mavic mini uses 2s 2400mah battery and gets 30min of flight time. it's also 249g

found a teardown here https://www.rcgeeks.co.uk/blogs/news/dji...ats-inside

So your 21min isn't bad at all

Thanks for the link.   

I enjoy seeing the tear down. 

Given that I use the Phantom-X as a test platform and it is a little "heavy" for the size, I think that I could build a lighter weight 4 inch that might get a few more minutes out of the batteries. 

{2020-10-17}

Before making another major change, I have decided to try the Phantom-X with prop guards; so I added a set of GEPRC Propeller Guard for CineRun 3 inch (set of 4) with AVAN Mini 3 inch props; these ones are pretty much the big brother of the AVAN Rush 2.5 inch props.

I want to test the "guarded" 3 inch running the 1303 5000kv FPV Cycle motors. Yeah, they have 2mm shafts, so I had to drill out the center hole to fit them on the motors; not really an issue since I bolt on the props. 

The hover test was performed in the house. Since the hovering went OK and my didn't seem to object, I flew it around the house for a bit. Even though it is quit a bit larger than my "tiny" whoops, the prop guards and fact that it was extremely stable in flight, alleviated any concerns about flying it in the house. But now, I need to take it to the field. 

More later... stay tuned...

{Update}  

I took the Phantom-X out today. Even though it was quite windy, the quad flew really well; I was impressed. The flight was stable and had no problems handling the wind; very smooth and easy to handle. 

Although I wasn't expecting very long Fly Time, she flew for over 7 minutes before the video went out and still had 11.4 volts on the pack  {3.80 volts per cell} which would have flown for quite a bit longer. The video was sketchy even from lift off...sometimes it would clear up, then get a little fuzzy, back and forth until it finally just gave out. Back home, I did some testing and the video range was awful. It did not even come close to my GEPRC Phantom on the 25mW setting. Time to upgrade...I really wanted to swap out the electronics anyway. Now this is my excuse. 

Really great series of posts iFly4rotors! I'm working on a long range <250g 2.5" or 3" build as well (https://intofpv.com/t-fun-with-ecalc) and could've saved myself some time if I found your posts first! If you have time, I'd love to get your feedback.

BTW, eCalc now has a number of smaller motors available (and also gives you the option of fully defining motors, batteries, etc without having to rely on presets), and appears to be much better at modeling smaller quads now than in the past.

(04-Jan-2021, 06:35 AM)V-22 Wrote: Really great series of posts iFly4rotors! I'm working on a long range <250g 2.5" or 3" build as well (https://intofpv.com/t-fun-with-ecalc) and could've saved myself some time if I found your posts first! If you have time, I'd love to get your feedback.

BTW, eCalc now has a number of smaller motors available (and also gives you the option of fully defining motors, batteries, etc without having to rely on presets), and appears to be much better at modeling smaller quads now than in the past.

Hi V-22,

Thanks. 

If you look through My Journal, you know that my quest and primary objective is to get as much Fly Time as possible form a sub 250 gram quad. As an adjunct, I would now like to get my 5K badge; so now it is Time and Distance. You will also find information that transcends multiple builds, general findings, and my journey through FPV. I also have a downloadable Parts Guide that is very useful.

When I first researched eCalc, it just didn't seem to be an effective tool for me; great for the larger quads, but they didn't seem to cater to the smaller builds. I will have to take another look at it; might be useful. 

You might be interested in some of my thoughts. Check out Post #101 in My Journal. 

2021-01-19        Time for an upgrade.

I have disassembled Phantom-X for some upgrades; I now want to set him up for Long Range use. 

While apart, I am also shortening the arm extensions. Recall, in the original build, the frame is a 2.5 inch GEPRC Phantom with Micro Alien 3 inch arms used as extensions for the base plate; set to accommodate 4 inch arms.  I used these arms because I just happen to have them in the parts bin; so why not. Since these are actual arms they are drilled to accept motors. All I had to do was mount them...just as they are; OK, I had to drill mount holes. These arms were then bolted to the Phantom frame's motor mount locations using 2 bolts.

When I used this approach, there was some concern about stress on the original frame, but I have had no problems with the setup. The quad has been flown a lot; yeah crashed a lot, too. So, now I am confident that the methodology is sound, although I did not think of this ...I saw some similar extensions somewhere else.

Here are the details of the changes. The Micro Alien Arms were marked, removed, cut down, and then bolted them back on; one at a time. 

The weight of the entire assembled frame package with 1303 motors and 4 inch props is 62 grams.

About 2 months ago, I purchased a Flywoo GOKU F4 35A STACK V2.1  16x16 complete include the VTX625 {directly from Flywoo} 
The FC and ESC stack weighs 7 grams without the VTX.

Since I didn't have any other specific use for it, I have decided to use this stack for the Phantom-X upgrade.  

WOW    This Stack is SWEET  

Even though it has an F411 processor which has only 2 hard UARTS, the FC board has 2 pads, TX6-RX6, that are dedicated for use with SOFTSERIAL which is already set up in Betaflight 4.2.0. Moreover, these are already set up for the VTX. Hard UART2 is already set up for the GPS. 

In fact, it looks like this stack had been set up for a Flywoo Explorer because everything is set up including the GPS Rescue Mode, the VTX table, and the OSD screen. WOW, they put everything on that screen    It is the first time that I have seen this; mostly there is nothing on it.

Now, I am thinking that I like this. I will give Flywoo 2 thumbs up   

{UPDATE}  

Yes, it also has 8 MB on-board Blackbox memory.

{2021-02-19 UPDATE}

Added wiring diagram for the GOKU F4 13A 16x16 stack with GPS.

Reaching out to V-22,

Will you run eCalc metrics on my Phantom-X with the following specs:

FPV Cycle 1303 5000kv
4 inch Gemfan Hurricane 4024 props
Dry Weight of 110 Grams

AUW with 3S 1100 mAh GNB battery = 176 grams
Fly Time = 17 minutes, 20 seconds

AUW with 2S 18650 3000 mAh cells in a plastic holder = 226 grams
Fly Time = 21 minutes, 20 seconds

Also...

GEPRC Phantom - All stock - No mods - No changes.
GEPRC GR-1103 8000 KV
2.5 inch push on props; I think HQProp, the stock ones that it comes with.
Dry Weight of 58 grams

AUW with 3S 1100 mAh GNB battery = 124 grams
Fly Time =  17 minutes, 26 seconds

AUW with 3S 650 mAh GNB battery = 105 grams
Fly Time = 12 minutes, 44 seconds

Thanks, I really appreciate it. 

Unfortunately neither of those motors have published specifications as far as I can find, so these numbers will be approximate using the closest motor I can find.

(31-Jan-2021, 08:31 PM)iFly4rotors Wrote: Reaching out to V-22,

Will you run eCalc metrics on my Phantom-X with the following specs:

FPV Cycle 1303 5000kv
4 inch Gemfan Hurricane 4024 props
Dry Weight of 110 Grams

AUW with 3S 1100 mAh GNB battery = 176 grams
Fly Time = 17 minutes, 20 seconds

AUW with 2S 18650 3000 mAh cells in a plastic holder = 226 grams
Fly Time = 21 minutes, 20 seconds

GNB 3S:
   

2S 18650:
   

(31-Jan-2021, 08:31 PM)iFly4rotors Wrote: GEPRC Phantom - All stock - No mods - No changes.
GEPRC GR-1103 8000 KV
2.5 inch push on props; I think HQProp, the stock ones that it comes with.
Dry Weight of 58 grams

AUW with 3S 1100 mAh GNB battery = 124 grams
Fly Time =  17 minutes, 26 seconds

AUW with 3S 650 mAh GNB battery = 105 grams
Fly Time = 12 minutes, 44 seconds

Thanks, I really appreciate it. 

GNB 3S 1100:
   

GNB 3S 650:
   

Hi V-22,

Thank You Very Much           
I REALLY appreciate it    

It looks like the eCalc results support my actual Fly Times which is good. Since I fly easy, it doesn't take much throttle. (you can see my style of flying from the videos in My Journal). So, it is realistic that my actual Fly Times are within, but a little less than, the eCalc estimated hover time. 

You know, that little 2.5 inch GEPRC Phantom flies for 17 minutes on a 3S 1100 mAh GNB battery. Some have wondered how I get 17 minutes from a 2.5 inch quad, but eCalc supports that Fly Time with an estimated hover time of 21.6 minutes. When you consider my flying style, that seems to be right in line. Anyone should be able to duplicate that if they fly like I do since this quad is ALL STOCK {Ok, I might have added a self powered ViFly buzzer, but that is it}. That said, I believe the 3S 1100 mAh GNB battery to be about as big as it gets.

You know, I never let conventional wisdom or established norms get in my way; I don't mind playing "Outside The Box". 

It looks like eCalc has come a long way since I took a look at it. Also, you paid to get all of the features, I did not. I am actually impressed by how close it is; not bad considering we don't really have all of, nor necessarily accurate, input variables. Depending on where my journey leads me, I might reconsider whether it is worth paying for. 

Thanks Again  

Surprised someone doesn't make slotted arm extensions for various frames in order to lengthen or shorten the arms.

That would be a more refined way of doing what OP did. But I'm digging the idea. Ohh the versatility!