2020-12-28

Since I am taking a short break from the 7 inch builds, I want to put together something that I can fly in the house.

One of the builds will be a straight forward {I Hope} 2 inch (85mm frame) tiny whoop {waiting on some parts}.

NOW, are you ready for another one of my Frankenbuilds    

I just happen to have 
a set of Taycan 2.5 inch ducts, 
some assorted frame base plates, 
motors, 
flight controllers, 
etc. in the parts bin,

...so... think I will 

throw some stuff in the mix, 
shake well, 
blow some magic dust on it, 
and see what I come up with. 

   FrankenFly-2-4  

You can fly the 7" in the house..............

(28-Dec-2020, 07:54 PM)kaitylynn Wrote: You can fly the 7" in the house..............

Hi Kaity,

That's funny     Normally, when I do a short, low altitude, hover test in the house, my wife    is OK with it, but, when I tried to fly the 5 inch, she said that it was too big,  NOT in the House. So, I kind of got my wings clipped for the larger drones. In fact, I don't even fire up the 4 inchers anymore. Fortunately, she is Ok with ducted quads; they appear to be safer to her.   

The BEAST was being a little bit challenging, so I was ready for a break ... before I construct an external circuit for the CAM feed {having ripped off a PAD. My fault, not any issue with the FC}. That is the primary reason that I got a Digital Microscope for Christmas.

The Katarms-LR7x was coming along, but I decided to use a different FC that I didn't yet own, the JHEMCU F722 AIO 30x30 single board flight controller. Since I am fabricating the central frame plates, I can drill it any way that I want, so I thought I would try this new board.

Now, the.ronin just finished a build using the Diatone Taycan 3 inch frame; NICE. Then, Bill just bought a Diatone Taycan 2.5 inch BNF. Ok, so now I want to build one. Thing is, I a have been contemplating a pusher for some time, just hadn't gotten around to it. Yeah, several months ago, I bought a set of Diatone Taycan 2.5 inch ducts; No frame kit, just the ducts. Wondering what I had in the parts bin, I found an Armattan Gecko 4 inch base plate, a set of Flywoo NIN 1404 4850 kv Dave_C FPV motors,...and... I will use the JHEMCU GHF-420 AIO (20x20) single board FC that I was going to use in the Katarms-LR7x. WOW, I have everything that I need for the build without actually buying anything; AMAZING    Being a project of hodge-podge parts, I am calling it FrankenFly-2-4    I think that the name fits. Yeah, I will need to fabricate at least one bottom frame plate; maybe use plexiglass   

     

2020-01-02

FrankenFly-2-4  Is ALIVE      

I got him finished late yesterday, fired him up, lift off, hover around for bit, and land. SUCCESS  

After flying around the living room, my darling Wife   says that he is too big to fly in the house; got to respect that 

This quad is putting out a lot of thrust and blows around everything that is not tied down. 

We have other plans, so I won't get to a fly field until tomorrow {maybe}.

So, if I am going to fly inside the house, I will need to put together the 2 inch tiny whoop.   
This one should be pretty simple, so I might go ahead and get it done.



FrankenFly-2-4 build thread.

How cool is that! Great build, really unique and look forward to following your flights!

Hi Kaity,

Thanks. 

I will get a flight in as soon as I can get to the field. I am really excited about this build. Even though it is heavy {186 grams dry weight} for a 2.5 inch, it seems to have more power than I was expecting. The Flywoo NIN 1404 4850kv motors have a little higher kv than I had been using, but that might be a good thing. I am really interested to see what kind of Fly Times I get with him. Even though the 3s 1100 mAh GNB battery pushes the AUW to 255 grams, that is where I will start my testing. Since I fly everything with this battery, I will be able to tell how it compares right up front. 

Following wllmlutz's Shocker build thread, it seems that 1000kv goes a long way with these small motors.

3S with those motors will likely be peppy. I fly the 3750's and on 3S they are adequate, but they are just at a point where 4S is perfect. Higher KV with the lower voltage will allow you to keep the throttle better constrained. I get six minutes on "fun flights" with just 650's on the leaf. Would guess cruising, you will likely net 8 to 10 minutes.

Yeah, I would be happy with that; especially since FrankenFly-2-4 was more of a concept build than an endurance build.

Ronin's Diatone Taycan ducted pusher build was my first real inspiration; 
Then Bill got a Diatone Taycan 2.5 inch BNF.

Now, I knew I had a set of Taycan 2.5 inch ducts laying in the parts bin, so...here we go...let's just build one. 

Yeah, mine is little different because it was built with parts I just happen to have in the parts bin; didn't buy anything. 
It was pretty much a Frankenstein build; hence the name.

2021-01-04     As we bring in the new year, let me start with some of my thoughts and direction.

As you may know, my primary object and quest is to get the most Fly Time that I can from a sub 250 gram quad and stay "under the radar"; that is to say fly in the recreational only "exemption" category as defined by the FAA. With that in mind, my focus is on the lightweight endurance quads. On the other hand, I do have two 7 inch builds that will likely be outside that range, but I got to try. These may well be my last over 250 gram craft and might be wall ornaments in the future. 

As an adjunct to getting the most Fly Time, I am now also working on distance; I want to get my 5K badge. In order to accomplish this, I have pretty much resigned to the fact that such a craft will likely have an All Up Weight (AUW) including battery and payload that is greater than 250 grams. So this is now one of my goals which I need to accomplish before the new FAA regulations take full effect. 

Since I am an easy cruiser {no racing, no acro, no punch outs}, I focus more on efficiency and endurance than raw performance. 

To this end, I may push established norms or think outside the box. I tend to over prop the motors a bit and I will modify or fabricate light weight components. That said, I will sometimes put a quad together just to see how it works or if it can be done successfully. Consequently, my builds are always subject to modification and experimentation. For this reason, I use a lot connectors on the components instead of direct soldering. I realize that this methodology does add a little weight, but if I get a build that I want to keep that way or really want to eek out the absolute lightest weight, then I will just remove the connectors and solder directly to the FC. 

On builds that are fitted with a GPS unit, I am now using an external 5V BEC to power the GPS. I picked this up from one of TMac's videos as a method for fast satellite acquisition. The weight of the BEC is insignificant and, in my opinion, well worth the effort.  

Even though I have always had a focus for extended Fly Times, the concept of going the distance and getting my 5K badge adds a new dimension. Since distance is a function of both Fly Time and Speed, just getting the Fly Time is not sufficient and when you factor in speed the battery drain changes. {more on this topic later}.

Fly it like you stole it; This is how I fly:

1) Prepare the quad(s) at home; strap on the battery and get ready for the flight.
2) Drive to a fly location {yeah, I can't really fly at home}.
3) Get ready as quickly as possible; Turn on transmitter and goggles.
4) Set a quad on the launch pad.
5) Lift off and Fly.
6) Repeat steps #4 and #5 for remaining quads.
7) Don't stay at the location longer than 30 minutes
8) Pack up and Leave.

I don't change batteries or work on my quads in the field. 
If anything goes wrong with a quad, it is packed up and diagnosed on the bench. 

So here we go; let's Build, Fly, Crash, Repeat.... 

Sound plan, Harry! This is actually how I plan on dealing with the rules as well.

Now, my opinions regarding sub 250 gram long range quads.

As I understand, the DJI Mavic Mini comes in at 249 grams with a 2s 2400 mAh battery and is said to get 30 minutes of Fly Time. On the other hand, at what speed and how far will it go    Will it make 5K out and back 

So, this might be considered a benchmark or "target" for a build. Can we do this with 2.5 inch, 3 inch, 4 inch 

So far, the 4 inch seems to be the most likely prospect.

Regarding the current flock of 4 inch long range quads, they come in under 250 grams with a relatively light weight battery. On the other hand, they are only getting those extended {25-30 minute} Fly Times with a heavy {200 gram} 4s 18650 3000 mAh Li-Ion battery pack which pushes the All Up Weight well over the 250 gram mark and beyond the FAA recreational exemption. So, in my mind, we run the line here. So, anything that I can fly with an AUW less than 250 grams is considered to be a sub 250 gram craft even if it only flies for a few minutes with a smallish  battery. So, you pick a battery that will meet this criteria for the classification of the craft, then you put that big battery on for a long range run.    

At first, it seems that all you need is time. If you get enough time in the air, the distance should be no problem. Well, sort of. I believe the reality to be a bit different. Let's say, for example, that you are getting 20 minutes of Fly Time from a specific quad {this is quite in line, I have done this before} so you think that will be sufficient. But wait, what was your air speed? Don't know, well, add a GPS unit **. So, now you know your air speed and discover that the air speed is like 10 mph or maybe 15 mph. At 15 mph, you will cover the 3.1 miles {5K} in about 12 minutes. Now, the return trip is also 12 minutes which means you need more than 20 minutes of fly time.  At 30 mph you will get to 3 miles in about 6 minutes. Now we are talking. Out and back in about 12 minutes and maybe have a few minutes to spare. So, you kick the speed up to about 30 mph, now you find that the battery drains much quicker and you still don't make it. Do you see where this is going? Here's the thing, the bigger the prop, the more efficient, but also it takes more motor to pull bigger props. So, the trick is to get the largest propped quad that is still under 250 grams. At this point the 4 inch is coming in as the most likely size.

Now let's talk weight. That 2.5 inch and 3 inch will just not pull the weight that a 4 inch will pull at least not with small motors. Here's the thing, you need the power to pull that battery. Oh yeah, the sub 250 gram FAA exemption is All Up Weight which includes the battery and any payload such as a GoPro. That said, you won't get those Fly Times with small batteries. Now, a 4s 18650 pack {that you see the reviewers using to get those long fly times} weighs about 200 grams. So the minute you strap on that pack, you just blew the sub 250 gram mark right out of the water. 
 
How about slight of hand. You build a 4 inch sub-250 quad that you call Long Range. With a battery that will keep the AUW under 250 grams, it will fly, but NOT fly a long range distance. Ok, maybe out there, but not back. So, maybe a Point-To-Point run.

For the most part, you must use a substantial battery that pushes the AUW well over the 250 gram mark for true long range.
 
** Regarding the GPS, most FC boards in the 2.5 and 3 inch quad have F411 chips don't have 
     enough UARTS to support a GPS without using soft serial. For this reason, I have moved up 
     to FCs that use chips that have extra hardwired UARTS and TX-RX pad sets. 

Although I believe the 4 inch platform will prevail, I still work with the 3 inch quads to see how much Fly Time and distance that I can get from them. Plus, the smaller quads are just plain fun to fly.

(04-Jan-2021, 03:51 PM)kaitylynn Wrote: Sound plan, Harry!  This is actually how I plan on dealing with the rules as well.

Hi Kaity,

Yeah, we may also see a sort of different approach to long range flying for FPV pilots: Point-To-Point. 

The concept is not really new, my wife suggested it some time ago for my attempt at 5K runs. 
In my wife's    scenario, I would drop her off at a local establishment where she would have a beverage and wait, I would drive out 5K, launch the quad, fly to the establishment, land, and she would pick it up. Yeah, we would likely maintain an open phone line during the flight. Then I would drive to the establishment where we would have beverages together. SWEET. Yeah, I know it is a one way ride, but hey. 

Now, let's apply that to what we might consider any long range run. First, you pick the destination; Obviously, somewhere that you could retrieve the quad. You fly to the destination, keeping a watchful eye, then land. In the best scenario, you have a partner waiting. If alone, you drive close, but not up to the landing zone. Wait, relax, watch. After a certain amount of time, you go get your quad. 

If your partner picks up the drone and gets hassled by anyone, they say "Hey, Look what I found". If it gets confiscated, you lost a drone, but no fines. Of course, your partner would call you and let you know the status. 

(04-Jan-2021, 03:59 PM)iFly4rotors Wrote: Now, my opinions regarding sub 250 gram long range quads.

As I understand, the DJI Mavic Mini comes in at 249 grams with a 2s 2400 mAh battery and is said to get 30 minutes of Fly Time. On the other hand, at what speed and how far will it go    Will it make 5K out and back 

So, this might be considered a benchmark or "target" for a build. Can we do this with 2.5 inch, 3 inch, 4 inch 

So far, the 4 inch seems to be the most likely prospect.

Regarding the current flock of 4 inch long range quads, they come in under 250 grams with a relatively light weight battery. On the other hand, they are only getting those extended {25-30 minute} Fly Times with a heavy {200 gram} 4s 18650 3000 mAh Li-Ion battery pack which pushes the All Up Weight well over the 250 gram mark and beyond the FAA recreational exemption. So, in my mind, we run the line here. So, anything that I can fly with an AUW less than 250 grams is considered to be a sub 250 gram craft even if it only flies for a few minutes with a smallish  battery. So, you pick a battery that will meet this criteria for the classification of the craft, then you put that big battery on for a long range run.    

At first, it seems that all you need is time. If you get enough time in the air, the distance should be no problem. Well, sort of. I believe the reality to be a bit different. Let's say, for example, that you are getting 20 minutes of Fly Time from a specific quad {this is quite in line, I have done this before} so you think that will be sufficient. But wait, what was your air speed? Don't know, well, add a GPS unit **. So, now you know your air speed and discover that the air speed is like 10 mph or maybe 15 mph. At 15 mph, you will cover the 3.1 miles {5K} in about 12 minutes. Now, the return trip is also 12 minutes which means you need more than 20 minutes of fly time.  At 30 mph you will get to 3 miles in about 6 minutes. Now we are talking. Out and back in about 12 minutes and maybe have a few minutes to spare. So, you kick the speed up to about 30 mph, now you find that the battery drains much quicker and you still don't make it. Do you see where this is going? Here's the thing, the bigger the prop, the more efficient, but also it takes more motor to pull bigger props. So, the trick is to get the largest propped quad that is still under 250 grams. At this point the 4 inch is coming in as the most likely size.

Now let's talk weight. That 2.5 inch and 3 inch will just not pull the weight that a 4 inch will pull at least not with small motors. Here's the thing, you need the power to pull that battery. Oh yeah, the sub 250 gram FAA exemption is All Up Weight which includes the battery and any payload such as a GoPro. That said, you won't get those Fly Times with small batteries. Now, a 4s 18650 pack {that you see the reviewers using to get those long fly times} weighs about 200 grams. So the minute you strap on that pack, you just blew the sub 250 gram mark right out of the water. 
 
How about slight of hand. You build a 4 inch sub-250 quad that you call Long Range. With a battery that will keep the AUW under 250 grams, it will fly, but NOT fly a long range distance. Ok, maybe out there, but not back. So, maybe a Point-To-Point run.

For the most part, you must use a substantial battery that pushes the AUW well over the 250 gram mark for true long range.
 
** Regarding the GPS, most FC boards in the 2.5 and 3 inch quad have F411 chips don't have 
     enough UARTS to support a GPS without using soft serial. For this reason, I have moved up 
     to FCs that use chips that have extra hardwired UARTS and TX-RX pad sets. 

Although I believe the 4 inch platform will prevail, I still work with the 3 inch quads to see how much Fly Time and distance that I can get from them. Plus, the smaller quads are just plain fun to fly.

Yes! I fully agree with all of this.

Using the Mavic Mini 2 as a benchmark is a great idea, since it was designed and engineered from the ground up to be <250g AUW with maximum flight time. People have managed 10km flights with it, so it's possible.

The major points from their design are:
2s power - Like you said, 4s is a non-starter due to weight, and 3s would only leave about 100g for everything else. They seem to be using a custom 2250mAh 2s pack that weighs about 86g! I'm sure this size and weight were carefully selected, and it's amazing they can achieve 10km on that capacity.

4.7" props - They are also using custom 4.7" x 2.6" lightweight props. I assume this was also an engineering decision as the best compromise between efficiency (larger prop size) and weight (due to longer arms/ larger frame). 4.7" gives you significantly more disc area than a 4" prop, which leads to higher efficiency.

One cool feature of eCalc is it gives you a flight time and range graph as a function of ground speed, both assuming no drag and assuming a standard drag coefficient of 1.3. The true range will likely be in between, but it does give you an idea of the relationship between speed and range.

Every motor/prop combination is going to have a throttle position/current draw at which it is operating at maximum efficiency. Your best range is going to be operating at this speed.

Lastly, I think due to the increasing popularity of sub 250g builds, there are a huge number of F7 (and even H7) based micro and whoop size FC/ESCs being released. No shortage of UARTs on those! Only downside is price, but they'll drop eventually.

Keep up the good work! I'll document my build as well, let's see if we can crack this!

Hi V-22,

Thanks for all of that very useful information. I think my next build will be based on those numbers. My guess is that they are using Li-Ion batteries that are smaller than the 18650 packs that are normally used. I have looked at small ones myself such as the 3.7 volt 14500 3150mAh.
Yes, the battery is the key.

Interestingly, I am working on a 7 inch build using the new iFlight BEAST 55A whoop format AIO which uses the H7 processor. 

Yeah, let's see if we can get a true AUW sub 250 that will actually go long range.  

I think 4" will definitely be easier than 3". What is the lightest weight 4" frame we can use as a base?

I'll run some numbers and see if we can do it on 2s!