*Unofficial* FT Dart
- Thread starter SP0NZ
- Start date
Morgan
Active member
Yea I think we all deal with that!! ☺
Enos Shenk
New member
Well, I killed mine. The person I was flying with wanted to see it go full speed. It did go max throttle, but pitch oscillation killed me. Impressively it bounced about 5 feet up from the ground.
It didn't look so bad walking up, but one of the wings completely split off, only hanging on by the bottom paper and a bit of foam. One motor nacelle was flopping around a bit as well. So naturally I tossed it back into the air. I mean, if it's already damaged why not damage it more and see if it would still fly?
It flew bad, obviously. But I did keep control of it, one of the props was a bit bent and the somewhat flappy wing caused some trouble. But I got it into the headwind and cut power, and it still glided like an absolute champ.
So one thing I did notice. There's a lot of adverse pitch when throttling up, I'm guessing the under-slung motors being offset from the CG causing the plane to pitch up when throttled higher. On mine I didn't build the wood nacelle supports. I built it from plans, and those parts aren't really feasible to scratch build. I wonder if the slight added weight of those parts would help with the thrust issues.
I did add in a bit of mix on my Taranis to blend in the throttle into the elevator mix, so as you throttle up it lessens the amount of reflex on the elevons. It helped, but didn't entirely cure the problem. Also at higher throttle the pitch gets very squirrely, I imagine more mix trickery could be used to lower the rates as the throttle increases.
I've already started cutting another one, going to get this one going butter smooth.
It didn't look so bad walking up, but one of the wings completely split off, only hanging on by the bottom paper and a bit of foam. One motor nacelle was flopping around a bit as well. So naturally I tossed it back into the air. I mean, if it's already damaged why not damage it more and see if it would still fly?
It flew bad, obviously. But I did keep control of it, one of the props was a bit bent and the somewhat flappy wing caused some trouble. But I got it into the headwind and cut power, and it still glided like an absolute champ.
So one thing I did notice. There's a lot of adverse pitch when throttling up, I'm guessing the under-slung motors being offset from the CG causing the plane to pitch up when throttled higher. On mine I didn't build the wood nacelle supports. I built it from plans, and those parts aren't really feasible to scratch build. I wonder if the slight added weight of those parts would help with the thrust issues.
I did add in a bit of mix on my Taranis to blend in the throttle into the elevator mix, so as you throttle up it lessens the amount of reflex on the elevons. It helped, but didn't entirely cure the problem. Also at higher throttle the pitch gets very squirrely, I imagine more mix trickery could be used to lower the rates as the throttle increases.
I've already started cutting another one, going to get this one going butter smooth.
mrjdstewart
Legendary member
yes!!! stephen just sent me my new VX-4 dart skins.
cant wait to print and build. probably start tomorrow.
on a side note, anyone got info on how to tone down the differential? i followed Josh's lead on the set-up but it's pretty much off or on. any way to control the amount allowed? i'd like to set it up just like my low/med/high rates. little bit leading into a lot.
flying a spektrum.
thanks,
me
cant wait to print and build. probably start tomorrow.
on a side note, anyone got info on how to tone down the differential? i followed Josh's lead on the set-up but it's pretty much off or on. any way to control the amount allowed? i'd like to set it up just like my low/med/high rates. little bit leading into a lot.
flying a spektrum.
thanks,
me
nevenelestate
No Agenda FPV
Have you made any progress on this build? I built my Dart with a Spectrum receiver and never really got it flying. I then bought an x9D radio so was going to swap out the receiver for FrSky one. I was looking on RMRC today and stumbled onto this TinyFish FC with built in receiver for $22 so I plan to try it out. I have done custom servo mixes in iNav and looking at the BF github stuff it appears to be the same so once I get mine in later in the week I will share my servo mixes once I get it sorted out.
Using this FC https://www.readymaderc.com/products/details/tiny-fish-f3-frsky-rx-2s
I plan to power the servos from the PDB that came in the Dart Power Pack.
**5/31 update - I had another nano FC in my spares and was trying to get it working yesterday. I flashed it with the newest BF and setup the configuration and ports and all, but couldn't get the servos to move. I ended up breaking the receiver's 5V wire off the board and didn't have a soldering iron handy so gave up on trying. Since my new FC should arrive today I decided to look into it a little more. This link should be handy https://github.com/betaflight/betaflight/wiki/Setup-for-a-Fixed-Wing-Aircraft
When I get it sorted out I will definitely share here and I will share the BF setup info here too.
Using this FC https://www.readymaderc.com/products/details/tiny-fish-f3-frsky-rx-2s
I plan to power the servos from the PDB that came in the Dart Power Pack.
**5/31 update - I had another nano FC in my spares and was trying to get it working yesterday. I flashed it with the newest BF and setup the configuration and ports and all, but couldn't get the servos to move. I ended up breaking the receiver's 5V wire off the board and didn't have a soldering iron handy so gave up on trying. Since my new FC should arrive today I decided to look into it a little more. This link should be handy https://github.com/betaflight/betaflight/wiki/Setup-for-a-Fixed-Wing-Aircraft
When I get it sorted out I will definitely share here and I will share the BF setup info here too.
Last edited:
mrjdstewart
Legendary member
skins printed, plans cut out. will spray tac them together tomorrow and let sit for a day.
don't mind the few "Bunny" P-51's parts thrown in, got 2 pot's on the burner.
pretty happy so far.
laters,
me
don't mind the few "Bunny" P-51's parts thrown in, got 2 pot's on the burner.
pretty happy so far.
laters,
me
nevenelestate
No Agenda FPV
I got my TinyFish F3 FC with FrSky receiver built in today from RMRC. I had already built up some pin headers that I could plug in 3pin servo leads to and had single wires coming off for the 4 channels. I soldered up the 4 wires then went into BF and setup the configuration for "Custom Airplane." I chose this over "Flying Wing" because BF only has a single motor output for Flying wing so I had to go in and manually setup the 2 motors. All of the motor and servo mixing info is at https://github.com/martinbudden/betaflight/blob/master/docs/Mixer.md . I set up the 2 motors and added in a yaw variable for differential thrust. since I will only use diff thrust for flat spins I set it to 1 or full, I then setup a switch on my Taranis radio that overrides the yaw stick so that I will only give BF yaw commands and get diff when I want it.
For the servos you need to do some mapping. You need to go into the CLI and get the list of resources, which for this board was very short. Note the addresses for M3 and M4, A03 and A02 for this FC. Then reassign them to "resource servo 1 a03" and "resource servo 2 a02." Then you need to setup some smix rules to give the servos the roll and pitch commands. There are several videos on YT about how to do it, but I found this one particularly helpful (yes it is for iNav, but the mixes are the same in both)
Hope to maiden her tomorrow, although the weather might say otherwise
Here is the FC with the wires and pin headers
And here is is installed in the Dart, I used the servo lead that was giving power from PDB to receiver to power the FC with 5V. I also turned it 90deg to have the USB port accessible for programming.
These are screenshots of the BetaFlight screens after I had it all setup.
This is the CLI Diff info, all the things in the code that I changed. This is a good starting point if you get the same FC, but be sure to verify all the servos and motors work properly with your specific setup.
20180531 BF FT Dart DIFF.txt
If you have any questions please post them here so others can get the info also.
For the servos you need to do some mapping. You need to go into the CLI and get the list of resources, which for this board was very short. Note the addresses for M3 and M4, A03 and A02 for this FC. Then reassign them to "resource servo 1 a03" and "resource servo 2 a02." Then you need to setup some smix rules to give the servos the roll and pitch commands. There are several videos on YT about how to do it, but I found this one particularly helpful (yes it is for iNav, but the mixes are the same in both)
Hope to maiden her tomorrow, although the weather might say otherwise
Here is the FC with the wires and pin headers
And here is is installed in the Dart, I used the servo lead that was giving power from PDB to receiver to power the FC with 5V. I also turned it 90deg to have the USB port accessible for programming.
These are screenshots of the BetaFlight screens after I had it all setup.
This is the CLI Diff info, all the things in the code that I changed. This is a good starting point if you get the same FC, but be sure to verify all the servos and motors work properly with your specific setup.
20180531 BF FT Dart DIFF.txt
If you have any questions please post them here so others can get the info also.
mrjdstewart
Legendary member
sorry, lot's of pots on the stove lately.
as you may know i asked Stephen to make me a custom skin for the dart. the first was jaw dropping beautiful (black bunny), but totally not what i was looking for. so, he graciously took another swing at it.couldn't be happier so far.
so may i present the HIGH visibility VX-4 Dart...
the bottom...
my 3D printed pods (not my design)
supposed to actually rain here in Tucson, imagine that, so prob no maiden until sunday.
laters,
me
as you may know i asked Stephen to make me a custom skin for the dart. the first was jaw dropping beautiful (black bunny), but totally not what i was looking for. so, he graciously took another swing at it.couldn't be happier so far.
so may i present the HIGH visibility VX-4 Dart...
the bottom...
my 3D printed pods (not my design)
supposed to actually rain here in Tucson, imagine that, so prob no maiden until sunday.
laters,
me
mrjdstewart
Legendary member
little bummed. hoped to maiden tomorrow but something is out of whack. since i installed the pack in the wing the right motor has stopped spinning up like it should. i can get it to go at high throttles and full rudder input for differential. but i cannot get it to run consistently with the other motor in normal mode. i even inhibited all the mixes for differential and just plugged both motor esc's into a y-plug. same issue. i have checked and verified the mix setting with the video but i still think it is a programing/Tx issue.
what could i be doing wrong?
thanks,
me
what could i be doing wrong?
thanks,
me
mrjdstewart
Legendary member
it's all programing. still haven't solved it but it's definitely in the transmitter.
i messed with the offset for the mix on the Aux1 and now i can get the right motor to spin up but it still isn't consistent with the left.
will keep digging.
me
i messed with the offset for the mix on the Aux1 and now i can get the right motor to spin up but it still isn't consistent with the left.
will keep digging.
me
mrjdstewart
Legendary member
ok. kinda bummed and need some input. not sure what is going on.
symptoms...
wing binds normal, has all control surface movement correct, problem is the motors and not spinning up even.
the left motor works as should will spin up normal and responds to rudder mixing properly. the right motor however will not respond to throttle until over 50% or 50% rudder.
i have verified the differential mixing, i have since used the exact mix on 2 diff planes without issues, so i know its not the "mixing."
i thought it may be an old setting from my first dart so i deleted the model, rebuilt it, and re-programed the mixing just to be safe. no change at all.
i thought it may be a throttle range issue, so i tried to set throttle range but had all sorts of issues with the right motor and esc. the left side worked as usual, throttle at full on tx, plug in battery, wait for 2 beeps, then close throttle to zero, then the esc sings it's little song and all is good. when i try that on the right side, i don't get the 2 beeps and the motor just goes instantly to full throttle. when i throttle back to zero, it just stops, no esc beeping, and i have full surface area control.
i also thought maybe throttle timing but since this esc has 1 wire missing, my programing card will not work.
any ideas guys?
gonna be really bummed if i have to scrap another custom skinned Dart.
thanks,
me
symptoms...
wing binds normal, has all control surface movement correct, problem is the motors and not spinning up even.
the left motor works as should will spin up normal and responds to rudder mixing properly. the right motor however will not respond to throttle until over 50% or 50% rudder.
i have verified the differential mixing, i have since used the exact mix on 2 diff planes without issues, so i know its not the "mixing."
i thought it may be an old setting from my first dart so i deleted the model, rebuilt it, and re-programed the mixing just to be safe. no change at all.
i thought it may be a throttle range issue, so i tried to set throttle range but had all sorts of issues with the right motor and esc. the left side worked as usual, throttle at full on tx, plug in battery, wait for 2 beeps, then close throttle to zero, then the esc sings it's little song and all is good. when i try that on the right side, i don't get the 2 beeps and the motor just goes instantly to full throttle. when i throttle back to zero, it just stops, no esc beeping, and i have full surface area control.
i also thought maybe throttle timing but since this esc has 1 wire missing, my programing card will not work.
any ideas guys?
gonna be really bummed if i have to scrap another custom skinned Dart.
thanks,
me
Morgan
Active member
so I had this hapen to me and i found out you use the off set on the mix with the throttle as master and aux 6 as slave , I believe you offset it to -48%. hope this helps.ok. kinda bummed and need some input. not sure what is going on.
symptoms...
wing binds normal, has all control surface movement correct, problem is the motors and not spinning up even.
the left motor works as should will spin up normal and responds to rudder mixing properly. the right motor however will not respond to throttle until over 50% or 50% rudder.
i have verified the differential mixing, i have since used the exact mix on 2 diff planes without issues, so i know its not the "mixing."
i thought it may be an old setting from my first dart so i deleted the model, rebuilt it, and re-programed the mixing just to be safe. no change at all.
i thought it may be a throttle range issue, so i tried to set throttle range but had all sorts of issues with the right motor and esc. the left side worked as usual, throttle at full on tx, plug in battery, wait for 2 beeps, then close throttle to zero, then the esc sings it's little song and all is good. when i try that on the right side, i don't get the 2 beeps and the motor just goes instantly to full throttle. when i throttle back to zero, it just stops, no esc beeping, and i have full surface area control.
i also thought maybe throttle timing but since this esc has 1 wire missing, my programing card will not work.
any ideas guys?
gonna be really bummed if i have to scrap another custom skinned Dart.
thanks,
me
mrjdstewart
Legendary member
ok. thank for the input. i had messed with offset a little but figured i shouldn't need anything considering, 1) Josh didn't show any during build video, 2) i have been successful using this exact mix on 2 other planes without issues.
not sure why this one is having problems.
anyways, if i dial in -82% offset on my throttle/aux1 mix, i get both motors spinning up as close as i can get them. the issue is now, when i use differential the right motor spins up much fast than the left with the same amount of rudder input.
guess i need to add another offset to the rudder mix?
i will keep playing with it. at least i can now fly it hopefully. i think i will put the diff thrust on a switch so i can fly with and without.
laters,
me
not sure why this one is having problems.
anyways, if i dial in -82% offset on my throttle/aux1 mix, i get both motors spinning up as close as i can get them. the issue is now, when i use differential the right motor spins up much fast than the left with the same amount of rudder input.
guess i need to add another offset to the rudder mix?
i will keep playing with it. at least i can now fly it hopefully. i think i will put the diff thrust on a switch so i can fly with and without.
laters,
me
mrjdstewart
Legendary member
dx8 Gen2
thanks, but for some reason i doubt it will be the same. everything about this screams goofy. but i will try.
i plan to fly it tomorrow and see what we have. by tomorrow mid-morning it may no longer be an issue....
we will see in the morning.
thanks,
me
thanks, but for some reason i doubt it will be the same. everything about this screams goofy. but i will try.
i plan to fly it tomorrow and see what we have. by tomorrow mid-morning it may no longer be an issue....
we will see in the morning.
thanks,
me
mrjdstewart
Legendary member
nope. epic fail. didn't even try and put it in the air. it was immediatly obvious on spin up that the motors weren't even close. back to step 1 and no clue as to where to go next. i guess i will just keep playing with until either it works or i get frustrated and rip the plane apart.
laters,
me
laters,
me
mrjdstewart
Legendary member
ok, so i'm a little closer. i re-set the throttle range on both ESC's again and that seems to have solved the timing issue. both motors spin up as expected on pure throttle. but.....when i throw rudder into the mix. the left motor is 3x's as powerful in it's response to input. if i spin up the left motor is is powerful and you can hear the motor working and it wants to twist our of my had. this is with minimal rudder input. when i switch to the other direction, the right motor spins up but has nothing in comparison thrust wise and this is with full rudder input. seems like it's hardly spinning.
thoughts?
thanks,
me
thoughts?
thanks,
me
JGplanes
Active member
I made pusher version. Didn't fly
I LOL'd when I saw the wrenches on the front! I guess I'm not the only one who uses tools for extra weight. Strips of nail gun nails are my personal favorite.
JG
