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Pumpkin drop event

ZOHD Talon Rebel GT aka the Galleon DT(FB)

CapnBry

Well-known member
#23
Sorry if you covered it but how many sheets does the fuselage take?
Yeah the PDF is sized to a sheet of DTFB, so the whole fuse takes one sheet. That doesn't include the nose cover, which on mine I just put it nose-down on a piece of scrap foam and cut it to size. I still need to make a camera holder nose but I'm procrastinating because it may be hard.

I've got iNAV installed inside now and got it all set up last night. I took it out for a test flight and oops, got my orientation wrong so it immediately goes into a roll of death when you turn on stabilization. About to head out this morning and give it another go.
 
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mayan

Well-known member
#24
Yeah the PDF is sized to a sheet of DTFB, so the whole fuse takes one sheet. That doesn't include the nose cover, which on mine I just put it nose-down on a piece of scrap foam and it to size. I still need to make a camera holder nose but I'm procrastinating because it may be hard.

I've got iNAV installed inside now and got it all set up last night. I took it out for a test flight and oops, got my orientation wrong so it immediately goes into a roll of death when you turn on stabilization. About to head out this morning and give it another go.
Good luck!
 

CapnBry

Well-known member
#25
We dooed it! I had plans of putting the VTX in the wing like you see on so many builds, but ugh, then I'd have to make a cable and dig out chunks of foam from my pretty wing and who has the motivation for that? I just cut a hole in the side of the fuselage and trapped the VTX between two layers of tape. I got a little carried away on cutting so the hole is a little big but nothing life-threatening.
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I also made a quick insert for the cameras. I had a real problem here since I planned to insert it from the front and then use something to lock the camera unit with the action camera and the FPV camera in place. I didn't really think it through because the nose comes to a point in the vertical axis so it can't take in something wider than the orifice. No problem, I'll just come in from behind and the vertical slopes will lock it in that way! Nope, the body tapers so the canopy opening is too narrow to fit anything that would fit snugly in front of it. Oh well, I just cut down the block a little until it fit in through the canopy area. It slides all the way forward and there's a magnet on the roof that prevents it from sliding back.
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You can see it is a little "gappy" up there. Everything is just press fit into place. The right side of the action camera (left in photo) inserts into a hole in the camera pod, and the same with the FPV camera. The two are just the right width that they wedge against each other. There's a hole in the top of the pod to allow me to press the buttons to start recording, so I just push it from the front to disengage the magnet, press the button then push it back in. Very simple single step.

But enough of this chit-chat, yak-yak and flim-flam. Just refrain from hibernating and we'll all enjoy the show. (Youtube is taking its sweet time processing this, it should be up soon)

You can tell when I'm in ANGLE mode, since the autotune procedure made the pitch bounce up and down. Just need to dial down some of the PIFF gains there. The V-Tail has the 60/40 elevator/rudder mix I had before and it feels like it isn't enough in manual mode so I might try 60/50. It takes like a year to rudder turn this baby around. Other than that, this build is done apart from some minor tweaks of the iNav settings. New equipment:
  • Omnibus F4 Pro v2 Flight Controller
  • Beitian BN-180 GPS
  • Akaso V50 Pro Action Camera
  • FrSky R-XSR receiver
  • 18A T-Motor ESC
  • AKK X2M VTX (maxes out at ~300mW despite claims, not recommended)
  • Foxeer Monster mini FPV camera
  • 655g weight with everything on board, 125g is battery
 

mayan

Well-known member
#26
We dooed it! I had plans of putting the VTX in the wing like you see on so many builds, but ugh, then I'd have to make a cable and dig out chunks of foam from my pretty wing and who has the motivation for that? I just cut a hole in the side of the fuselage and trapped the VTX between two layers of tape. I got a little carried away on cutting so the hole is a little big but nothing life-threatening.
View attachment 132336

I also made a quick insert for the cameras. I had a real problem here since I planned to insert it from the front and then use something to lock the camera unit with the action camera and the FPV camera in place. I didn't really think it through because the nose comes to a point in the vertical axis so it can't take in something wider than the orifice. No problem, I'll just come in from behind and the vertical slopes will lock it in that way! Nope, the body tapers so the canopy opening is too narrow to fit anything that would fit snugly in front of it. Oh well, I just cut down the block a little until it fit in through the canopy area. It slides all the way forward and there's a magnet on the roof that prevents it from sliding back.
View attachment 132337
View attachment 132338

You can see it is a little "gappy" up there. Everything is just press fit into place. The right side of the action camera (left in photo) inserts into a hole in the camera pod, and the same with the FPV camera. The two are just the right width that they wedge against each other. There's a hole in the top of the pod to allow me to press the buttons to start recording, so I just push it from the front to disengage the magnet, press the button then push it back in. Very simple single step.

But enough of this chit-chat, yak-yak and flim-flam. Just refrain from hibernating and we'll all enjoy the show. (Youtube is taking its sweet time processing this, it should be up soon)

You can tell when I'm in ANGLE mode, since the autotune procedure made the pitch bounce up and down. Just need to dial down some of the PIFF gains there. The V-Tail has the 60/40 elevator/rudder mix I had before and it feels like it isn't enough in manual mode so I might try 60/50. It takes like a year to rudder turn this baby around. Other than that, this build is done apart from some minor tweaks of the iNav settings. New equipment:
  • Omnibus F4 Pro v2 Flight Controller
  • Beitian BN-180 GPS
  • Akaso V50 Pro Action Camera
  • FrSky R-XSR receiver
  • 18A T-Motor ESC
  • AKK X2M VTX (maxes out at ~300mW despite claims, not recommended)
  • Foxeer Monster mini FPV camera
  • 655g weight with everything on board, 125g is battery
Very nice man! i am going to build one too some time :).
 
#27
Finally to experiment with that horrible tip stall problem, I 3D printed a 256mm wide x 8% chord (14mm) x 2mm tall strip of vortex generators at a 12 degree angle and a 21.2774mm spacing (2 * 10 * vg_h * vg_d * 0.75 / (PI * PI * vg_h)). They are installed to end at 14% chord, so they start 11mm back from the leading edge.
Where does that formula come from? I've wanted to experiment with VGs, but wanted to try something more methodical than "put some bumps on the wing and see what happens".
 

CapnBry

Well-known member
#28
Where does that formula come from? I've wanted to experiment with VGs, but wanted to try something more methodical than "put some bumps on the wing and see what happens".
I got them from the FliteTest article of course!
Radius of Vortex = 10 * planform size * Cl / (pi^2 * height)

I'm not sure where that formula comes from, since the only other formula I have seen is in polar coordinates for the vorticity vector tangental to the circumference of the vortex (you might think that because I typed that, I understand how they get there, but I am just repeating what I have read). I looked at photos of full scale versions then did some rough math to see that the formula is at least in the ballpark. I also double it since it is the radius and we want a diameter spacing to prevent them from interacting with each other. I find it very weird that the radius of the vortex isn't dependent on Reynolds number or at least wind speed, but maybe the Cl takes that into account.

EDIT: After flying a few times now, the motor/prop/battery combination is fine in this setup. I cruise on 3S around 5 amps which is about 40kph. That's just ~60W for a 1.452lb (660g) model and surprisingly efficient for a such a flying brick. Right at the end I don't have enough power to do big loops or anything, but it is enough to go sightseeing. The FliteTest Radial 2212 is just under 10% more efficient as well, so that would be even better with this SF prop. That and a set of 4S1P 18650 cells will probably fly for 30-40 minutes.
 
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CapnBry

Well-known member
#29
Someone asked about how my cameras were mounted so here's a bit more detail. To make the carrier, I just used the plans for the sides, top, and bottom and just reduced them by one foam thickness so it would fit inside. I had to trim some of the back off since it didn't fit in through the canopy hatch hole. All the foam is hot glued in typical A or B fold fashion, then reinforced with packing tape. The inside bits I just cut to fit, then cut holes for the cameras to fit into. There's holes to access the camera buttons on the top, and a magnet mates with one in the fuselage nose just to keep it from sliding backward. This wasn't what I had planned originally, but the fit is perfect such that the two cameras wedge in just right so they don't fall out in flight. This carrier has also been in one major crash with no major damage to it-- it pretty much got thrown clear of the nose splitting open.
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I've been out of town for two weeks and look forward to flying the Galleon again. I'd gotten so confident in my flying that I was all "Landing downwind? Ech who cares" except I flared way too hard and fast so the nose popped up and stalled, I lost control and maxed the throttle... just as the nose went STRAIGHT down.
20190530_111711.MOV_snapshot_04.03_[2019.06.13_08.50.56].jpg

The nose split along the skewer reinforcements and popped open but some hot glue and it was back in business. Or I assume, I haven't flown it since and it is pouring rain now. This crash was almost a worst case scenario. I could have been going faster, but a steeper dive could not be achieved. The wings, v-tail assembly, canopy, and the fuselage from the canopy hole back are fine, you'd never know they were in a crash.
 

CapnBry

Well-known member
#30
I put an 8x6 APC Electric prop on in place of the 8x4.5SF and I got more power and a little more efficiency. At 4.25A I was cruising around at 50kph. I could tell right when I took off that I was tailheavy since the plane was eager to climb but I wasn't planning on flying long so I just ignored it and added some down elevator. Five minutes in and was just circling the field one last time before landing with the throttle real low, 2.5A / 27kph. The nose still wanted to bob up so I cut the power completely to see what would happen... huge tip stall at 98m! I rolled upside down, recovered, stalled full nose down again, and lost 60m of altitude in under 4 seconds. I tried flipping into stabilized ANGLE mode to let iNav do some magic, but I was too late: impact velocity was -25.83m/s or 93kph and over 12Gs of deceleration.
2019-06-15-2.jpg

The fuselage is toast. Even the 3D formed center support was ripped to shreds. The flight controller ripped loose and went flying. The MMCX antenna snapped off the VTX, which then burned itself out. Both V-tail fins snapped off. Even the GPS module, glued in its tiny protective area came loose and its wires sliced through the DTFB. The bbq skewers in the nose were exploded into woodchips. The AKASO V50 Pro action camera still works, but its LCD is shattered and just displays random pixels now so that's a loss. The Foxeer Monster FPV camera still works but there's a big scratch on the lens. So about $150 worth of electronics broken.

The wing is a real success story though, there were a couple tufts of grass stuck to it, and part of the paper covering chipped in one place, but it is 100% strong, unbent, and even the control surfaces are still solid. I'd say I'd build a new fuselage and get right back to flying, but it is a bit expensive to replace all the camera gear so the project will have to wait. I also think the lack of washout in the design helped contribute to the disaster so I'd probably want to do a new wing anyway which is a shame because this wing is so dang strong.

Galleon adventure OVER.
 

SquirrelTail

Well-known member
#31
I put an 8x6 APC Electric prop on in place of the 8x4.5SF and I got more power and a little more efficiency. At 4.25A I was cruising around at 50kph. I could tell right when I took off that I was tailheavy since the plane was eager to climb but I wasn't planning on flying long so I just ignored it and added some down elevator. Five minutes in and was just circling the field one last time before landing with the throttle real low, 2.5A / 27kph. The nose still wanted to bob up so I cut the power completely to see what would happen... huge tip stall at 98m! I rolled upside down, recovered, stalled full nose down again, and lost 60m of altitude in under 4 seconds. I tried flipping into stabilized ANGLE mode to let iNav do some magic, but I was too late: impact velocity was -25.83m/s or 93kph and over 12Gs of deceleration.
View attachment 133766

The fuselage is toast. Even the 3D formed center support was ripped to shreds. The flight controller ripped loose and went flying. The MMCX antenna snapped off the VTX, which then burned itself out. Both V-tail fins snapped off. Even the GPS module, glued in its tiny protective area came loose and its wires sliced through the DTFB. The bbq skewers in the nose were exploded into woodchips. The AKASO V50 Pro action camera still works, but its LCD is shattered and just displays random pixels now so that's a loss. The Foxeer Monster FPV camera still works but there's a big scratch on the lens. So about $150 worth of electronics broken.

The wing is a real success story though, there were a couple tufts of grass stuck to it, and part of the paper covering chipped in one place, but it is 100% strong, unbent, and even the control surfaces are still solid. I'd say I'd build a new fuselage and get right back to flying, but it is a bit expensive to replace all the camera gear so the project will have to wait. I also think the lack of washout in the design helped contribute to the disaster so I'd probably want to do a new wing anyway which is a shame because this wing is so dang strong.

Galleon adventure OVER.
That sucks! Though the project was a success!
 

Arcfyre

Well-known member
#32
Man that's a bummer. This thing was sleek as heck, I was a huge fan.

I know how it feels to lose a bunch of electronics at once too. It's heartbreaking. The maiden flight of my "camera ship" (modded blunt nose versa) ended in the pond. The impact was so strong it ripped the camera mount off of the fuselage and it sank. In one swoop I lost a $70 camera, $30 ESC, and $24 RX. Brutal day.
 

CapnBry

Well-known member
#33
In one swoop I lost a $70 camera, $30 ESC, and $24 RX. Brutal day.
Oof we share that feeling. This is actually the first recovered crash where there was damage to any of my parts, so my disappointment was spread across various highs and lows. I crashed. But it crashed on open ground so I don't have to fish it out of a tree! Oh the fuselage is busted up. But all everything is right here! X is broken. But X is only mostly broken!

The model itself wasn't a huge loss. A new fuselage could be built in a couple of hours at the most since there are plans. The V-tails could actually be reassembled with a little glue-- they came apart cleanly along the 45 degree bends. The scratch on the FPV camera turned out to just be stuck on Earth juice and cleaned off, looks 100% or close enough to it. The VTX I spent 30 minutes trying to extract the half of MMCX connector inside of it but eventually just desoldered the connector and soldered the antenna directly to the VTX. Seems to be working fine in pit mode now on the bench. The flight controller just had a connector pull up from the PCB and break off, and I happened to have something with the right size connector to sacrifice, so that seems to be working as well. The receiver was fine too once it got power.

So when I get down to it, really the only loss is the nice new 4K camera. It still records and the image looks fine! Without the touchscreen LCD, it will be impossible to change any settings from now on, but I guess that could be worse. If I can figure out how to turn on the wifi, I think the app lets you change settings remotely so that could be a work around. So I didn't end up losing much at all, just the plane. Everything else works much worse than it used to, but isn't that just how life goes? :-D

I took the time while everything was in pieces to thrust test the new 8x6 propeller. The 8x4.5SF puts out 15-20% more thrust across the throttle range and almost exactly the same power and marginally higher RPM. Since the 8x6 has 30% more pitch, it does generate more speed at any throttle position, but I think the lower thrust is what got me into trouble. I must have hit that point where the speed was close to the stall point I was used to, but since I was generating 20% less thrust and was tail heavy, everything just fell apart faster than I could figure it all out. I really wish I was recording because now it feels like a waste of a crash! Blackbox logs just aren't as satisfying as video.
 

CapnBry

Well-known member
#35
I made a new one using my plans. Conclusion: Don't use my plans! The plans are pretty close to right, with only one thing needing any real change, but I'll post new plans soon.
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From the first picture to having everything cut out and the main fuselage box glued up was under two hours, so pretty quick. I didn't like how the tail fit on so I redesigned it and built an new one and didn't like that one either. The third one I decided was good enough and finished it up. I've made a list of notes of other minor things to clean up in the plans. One major thing is I designed it for 24x30" DTFB and DTFB is 20x30 so I'm not sure how my brain failed on that one. Going to see if I can rearrange everything to fit on a single sheet as it should be.

Just the airframe with servos and rubber bands is sitting at 306g (with the dummy nose cover) and still super tailheavy with nothing on board. Correction to earlier measurements, the wingspan is actually 43" (1092mm) and 175mm in chord. I still need to hit the fuselage with some minwax, but I can't get to it in my garage for the next couple of weeks since it is full of solar panels and construction material while my roof is getting redone. It has been raining non-stop for 2 days though so I'm not sure I'd be able to fly it anyway. Florida!

In my signature style, 3 of my 4 BBQ skewers are in noticeably crooked. I do measure to try to get them straight every time but I think I'm just going to start jamming sticks in from now on since it clearly makes no difference in the final straightness.

EDIT: Forgot to say that my V-Tail in this design is slightly toed out now so it matches the fuselage angle. This might be a mistake. It definitely will cause more drag but we'll have to see if it is detrimental to the flight characteristics.
 
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mayan

Well-known member
#36
Happy to see you got back at it. I think this project if able to get it to fly good could be a great platform for air to air and air to ground footage and will definitely go on my build list.
 

CapnBry

Well-known member
#37
Finally had some reasonable weather! I forgot to add a switch to set the trims in iNav so the first flight was very nose-down. Normally that wouldn't be an issue but I was pretty nervous and really stuck the landing. By that I mean I threw it into the ground at over 50kph (30mph) groundspeed and turned it into a yard sale. Relatively minor damage although the whole fuselage looks like it has weakened a bit since it has creases on it now. Only needed to glue the top of the nose back on. Another landing went much more smoothly once everything was properly centered.

Not on film: The flight in between the two where I floated at chest height across the entire field with no power saying "ok land. land. land please. LAND. LAAAAND! (hits tree at the end of the field and snaps the wing in half)"

Still need to finish updating the plans but maybe one more PID adjustment flight and then we'll load up the FPV gear finally. I've been flying the whole time with the 8x6E prop on 3S. It's great at about 5A and going 60-70kph but drop below 4A and flying in manual gets a little dicey since thing takes a lot of altitude to recover from a bad stall. At 3A, don't even try anything but the mildest of maneuvers. The problem is that all that is in the 55-65% throttle range. I ended up adding a curve on the QX7 to compress most of the <50% throttle down below 20% of stick movement.
 
#38
I have been working on a version of this myself actually. Flew it for the first few times this weekend.

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I found the same issue with the aft end as you did during the build as I was referencing original product photos as well as your plans and build thread. Its even more pronounced in my case as all the hardware is what I had on hand so I'm running a 2306 1750kv with a 6x4 and there is literally millimeters of clearance at the tail and propeller tip. Im going to print a spacer/mount and give myself a couple 6mm more length just to be safe and maybe quiet the thing down a tad.

Flies for well over 25 minutes on a 2650mah 4s at about 50%-55% throttle. As you said it doesn't like to go slow, this thing is a barn burner for sure and once it gets down on the deck for a landing it just goes and goes and goes... Eventually you just have to shove it down onto the ground it seems.

Working on an edit of my last tuning/distance test and will post a link when it's up. Managed to hit 2.25 miles on 5.8ghz and not even very good conditions.

(Edit to include link)
iNav UAV Tuning Session

Glad to see you getting back into this project and am looking forward to seeing how it progresses from here.

-Clay
 
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#39
I have been working on a version of this myself actually. Flew it for the first few times this weekend.

View attachment 137435
View attachment 137436
View attachment 137437

I found the same issue with the aft end as you did during the build as I was referencing original product photos as well as your plans and build thread. Its even more pronounced in my case as all the hardware is what I had on hand so I'm running a 2306 1750kv with a 6x4 and there is literally millimeters of clearance at the tail and propeller tip. Im going to print a spacer/mount and give myself a couple 6mm more length just to be safe and maybe quiet the thing down a tad.

Flies for well over 25 minutes on a 2650mah 4s at about 50%-55% throttle. As you said it doesn't like to go slow, this thing is a barn burner for sure and once it gets down on the deck for a landing it just goes and goes and goes... Eventually you just have to shove it down onto the ground it seems.

Working on an edit of my last tuning/distance test and will post a link when it's up. Managed to hit 2.25 miles on 5.8ghz and not even very good conditions.

(Edit to include link)
iNav UAV Tuning Session

Glad to see you getting back into this project and am looking forward to seeing how it progresses from here.

-Clay
Do you have plans available for this? Looks great!
 
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CapnBry

Well-known member
#40
I have been working on a version of this myself actually. Flew it for the first few times this weekend.
iNav UAV Tuning Session
Wow that looks incredible! Looks like it flies great in the video too. Did you build that from my sketchy plans, because that would be a miracle.

I had the same issue with the PID gains being way too high and overshooting after Autotune. There was a whole lot of bob up and down especially, roll wasn't terrific, but yaw was ok. Now that build #2 has properly sized control surfaces I've been dialing it in a bit better. Here's what I'm running currently although I'm sure there can be a lot of variation due to where we put our control linkages.
roll -> roll_rate=20, fw_p_roll=12, fw_i_roll=10, fw_ff_roll=42
pitch -> pitch_rate=16, fw_p_pitch=10, fw_i_pitch=16, fw_ff_pitch=55
yaw -> yaw_rate=8, fw_p_yaw=20, fw_i_yaw=35, fw_ff_yaw=120