SR-72 DarkStar, 1:20 Scale, design by FoamyDM
- Thread starter FoamyDM
- Start date
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- skunk works sr-72 top gun
Quick update: OK... are all these FC far so difficult to wire up?
I soldered in the pins, thinking I could just use some servo connectors and be done... It feels as if I was wrong.
After figuring out about updating the board firmware (and Inav Confugurator) to the latest version. I started wiring up things.
GPS: the NZ GPS is... the wrong format?
Reciever: the Rx won't work (PWM is not supported any more) I was planning to user FS-IA6B, as it has PPM PWM but the IBUS is... weird,
FPV: the Video Signal is Fuzzy. the VTX is not functioning. It keeps rebooting, possibly a fix for it but it would be better for me to look for a spare).
so Now I need to think, Should try and find a replacement or just do it the old fashioned way.
In the meantime I need to focus on landing gear and servo installation
https://www.thingiverse.com/thing:3013977
FC advantages. - LED controls. (you can do some Fun stuff
Flight Stabilization. (better chance of making it home
FPV with HUD WAY cooler than just FPV.
GPS - Some nice Failsafe features.
I soldered in the pins, thinking I could just use some servo connectors and be done... It feels as if I was wrong.
After figuring out about updating the board firmware (and Inav Confugurator) to the latest version. I started wiring up things.
GPS: the NZ GPS is... the wrong format?
Reciever: the Rx won't work (PWM is not supported any more) I was planning to user FS-IA6B, as it has PPM PWM but the IBUS is... weird,
FPV: the Video Signal is Fuzzy. the VTX is not functioning. It keeps rebooting, possibly a fix for it but it would be better for me to look for a spare).
so Now I need to think, Should try and find a replacement or just do it the old fashioned way.
In the meantime I need to focus on landing gear and servo installation
https://www.thingiverse.com/thing:3013977
Last edited:
Baron VonHelton
Elite member
The real question is would you trust me with a soldering gun?
Con-FUG-erator?
Is that FUG in G minor? (Musician's joke)
If this doesn't work... I might switch to the Radiolink Byme A stabilizer. The link shows how to set it up through Open Tx.
Another example of how the module works.
Squirrel Moment:
Squirrel Moment:
Matthew Sanders
Elite member
I finished mine! About to go try it! Hopefully it works! Will update!
Matthew Sanders
Elite member
Oh and by the way, it has fixed landing gear now. I totally expect it to rip off on landing but then again I just need it to take off.
Matthew Sanders
Elite member
<sigh>
It’s in a tree.
A literal tree.
And it’s still there, destined to remain up there for the night, if not longer.
How did it get there you ask? Well, sit back, and enjoy the post, cause it’s gonna be a long one!
It has fixed landing gear, and before you ask, this is true fixed gear, with no steerable nose wheel. I meant it to be a hand launch/belly landing jet anyway, so the gear was an afterthought. I couldn’t make the servo fit, so I just lined the gear up and prayed it would go straight for the duration of the takeoff run.
Oh boy, did it do just that. It went straight for the takeoff run, all 5 feet of it.
Ok, ok, that’s an exaggeration. It was probably more like 10 feet, but waaaay less than what I expected for an experimental aircraft, that doubled as my first twin EDF running on a 3300 4s.
@FoamyDM I have some info for yours. The pitch rates are insane, and, so are the roll rates, so just beware of that. Set a really extreme low rate for the triple rates. Like, 40% DR, 45-60% expo. If it’s too low, set up your others how you’d like.
Anyway, it flew ok for about 10 seconds, before the bad characteristics reared their ugly heads. From T+ 10 seconds up until about 30-45 seconds after takeoff, I was fighting it to get into a landing pattern. A couple of times, I thought I had it, but then it’d do some crazy stuff. I swear, CG was good. It flew straight and level on the takeoff climb, after leveling out after the near vertical I pulled after rotation (approximately 80 degrees AOA). Unfortunately, my —— phone lost the takeoff and about 20 or so seconds of video, so all I have is the last 13 seconds of flight before it hit the tree.
How’d it hit?
well, after flying towards peoples houses (I fly at a golf course with houses surrounding it, I don’t fly over them intentionally) I fought to get it turned around towards me, acknowledging that this flight will most likely end with an intentional nose dive into the ground to avoid landing on personal property or in a lethal gator pond. I did get it away from the houses before it entered a flat spin (!) THATS right, a FLAT SPIN, folks.
I know what you’re thinking:
Just like the one that killed goose! Here’s the thing, both EDFs were producing thrust, I didn’t have differential thrust, and my rudders are fixed. So how in the heck did it enter a flat spin??? Either way, I had no way to bail out of it. I must admit, I panicked and added power to try to get the receding side to have thrust to get it out. That’s all I could do. I was too low above the trees, so I knew in a split second I was done.
Tango Down.
After 2 hours of trying to throttle it out of the tree, throw a rope to pull it out, SHAKE the tree, and use a ladder and pole to poke it out, it got dark. So, it will remain up there. For now, at least. Battery still connected.
Oh and by the way, if the battery runs down to 0 percent tonight, do I have to discard it? (Assuming I get it back)
So, that’s my story. Unfortunately, I only have a tiny amount of video (which in my opinion is the biggest loss, since now none of you will get to see my awesome STOL High-Hypersonic Technology Demonstrator.
Electronics MIA:
E-Flite F-15 Eagle 64mm EDF— EDF unit
E-Flite F-16 64mm EDF— EDF unit #2
E-Flite EC-1500 cargo plane— 2X 40A ESC + motor wire extensions + 5a UBEC
Spektrum AR620
2x FT servos.
1x 3300 4s 80C!!!
$6 WORTH OF DTFB
So, you’ve made it to the end. I’ll update on the damage if i get it back.
To be continued.
It’s in a tree.
A literal tree.
And it’s still there, destined to remain up there for the night, if not longer.
How did it get there you ask? Well, sit back, and enjoy the post, cause it’s gonna be a long one!
It has fixed landing gear, and before you ask, this is true fixed gear, with no steerable nose wheel. I meant it to be a hand launch/belly landing jet anyway, so the gear was an afterthought. I couldn’t make the servo fit, so I just lined the gear up and prayed it would go straight for the duration of the takeoff run.
Oh boy, did it do just that. It went straight for the takeoff run, all 5 feet of it.
Ok, ok, that’s an exaggeration. It was probably more like 10 feet, but waaaay less than what I expected for an experimental aircraft, that doubled as my first twin EDF running on a 3300 4s.
@FoamyDM I have some info for yours. The pitch rates are insane, and, so are the roll rates, so just beware of that. Set a really extreme low rate for the triple rates. Like, 40% DR, 45-60% expo. If it’s too low, set up your others how you’d like.
Anyway, it flew ok for about 10 seconds, before the bad characteristics reared their ugly heads. From T+ 10 seconds up until about 30-45 seconds after takeoff, I was fighting it to get into a landing pattern. A couple of times, I thought I had it, but then it’d do some crazy stuff. I swear, CG was good. It flew straight and level on the takeoff climb, after leveling out after the near vertical I pulled after rotation (approximately 80 degrees AOA). Unfortunately, my —— phone lost the takeoff and about 20 or so seconds of video, so all I have is the last 13 seconds of flight before it hit the tree.
How’d it hit?
well, after flying towards peoples houses (I fly at a golf course with houses surrounding it, I don’t fly over them intentionally) I fought to get it turned around towards me, acknowledging that this flight will most likely end with an intentional nose dive into the ground to avoid landing on personal property or in a lethal gator pond. I did get it away from the houses before it entered a flat spin (!) THATS right, a FLAT SPIN, folks.
I know what you’re thinking:
Just like the one that killed goose! Here’s the thing, both EDFs were producing thrust, I didn’t have differential thrust, and my rudders are fixed. So how in the heck did it enter a flat spin??? Either way, I had no way to bail out of it. I must admit, I panicked and added power to try to get the receding side to have thrust to get it out. That’s all I could do. I was too low above the trees, so I knew in a split second I was done.
Tango Down.
After 2 hours of trying to throttle it out of the tree, throw a rope to pull it out, SHAKE the tree, and use a ladder and pole to poke it out, it got dark. So, it will remain up there. For now, at least. Battery still connected.
Oh and by the way, if the battery runs down to 0 percent tonight, do I have to discard it? (Assuming I get it back)
So, that’s my story. Unfortunately, I only have a tiny amount of video (which in my opinion is the biggest loss, since now none of you will get to see my awesome STOL High-Hypersonic Technology Demonstrator.
Electronics MIA:
E-Flite F-15 Eagle 64mm EDF— EDF unit
E-Flite F-16 64mm EDF— EDF unit #2
E-Flite EC-1500 cargo plane— 2X 40A ESC + motor wire extensions + 5a UBEC
Spektrum AR620
2x FT servos.
1x 3300 4s 80C!!!
$6 WORTH OF DTFB
So, you’ve made it to the end. I’ll update on the damage if i get it back.
To be continued.
Last edited:
Baron VonHelton
Elite member
Provided you were high enough in the air, why didn't you CUT the power & let the plane right itself? Also, the fact that these aircraft do this in REAL LIFE has me concerned for our pilots.
Matthew Sanders
Elite member
Well, as I said I panicked, but also I don’t think it was high enough for a recovery. Also, I did google spin recovery procedure, and some results seemed to suggest that full power should be applied, as well as down elevator and in turn ailerons (and opposite rudder, although I had no yaw control on mine) all of which I did in my attempt to fly out of it.Provided you were high enough in the air, why didn't you CUT the power & let the plane right itself? Also, the fact that these aircraft do this in REAL LIFE has me concerned for our pilots.
Burnhard
Well-known member
I thought these aircraft are mostly flown by computers? The F117 maiden was with the flight stabilization turned off and they quickly learned that its rather hard to fly these without the computer.Provided you were high enough in the air, why didn't you CUT the power & let the plane right itself? Also, the fact that these aircraft do this in REAL LIFE has me concerned for our pilots.
Matthew Sanders
Elite member
Uhhh yeah. I found out it’s aerodynamically unstable in certain flight modes. But it shouldn’t have gotten into a flat spin. Anyway, it’s still stuck in the tree, looks like I’ll have to cut it down.
Still, the biggest blow of this whole fiasco is that I lost half of my flight footage.
Looks really GOOD! I have some videos coming.
You'll have to post pictures in https://forum.flitetest.com/index.php?threads/still-up-a-tree.68321/
Let's keep the tradition alive!
Matthew Sanders
Elite member
I will do that. I must say though, it’s hard to see a dark triangle shaped plane in a tree with dark green leaves, so I’ll probably have to mess with some filters to make it stand out!
Tench745
Master member
So, where can we find the half you didn't lose? Inquiring minds want to know.
Spins happen when there is a yawing moment of some kind and a wing stalls. GA aircraft are usually designed so that they are relatively spin resistant and some will not spin at all depending on their CG. In something like a Cessna typical stall recovery is: power to idle, ailerons neutral, opposite rudder to stop the spin, then proceed with a normal stall recovery. Flats spins are dangerous because you can lose all meaningful airflow over the rudder and elevator, so depending on the aircraft, they may be impossible to recover from without something else to stop the yaw of the spin, like differential thrust.
A stunning example of the effects of power on spins
Matthew Sanders
Elite member
You’ll have to watch the video when it gets uploaded. I’ll link it here. Yeah, I have no yaw control on this model whatsoever. Fixed vertical stabs, no differential thrust. To be honest, I didn’t expect it to be as unstable as it was. It entered a spin by not performing the commanded maneuver. In a left hand bank, right roll input pitched the aircraft like a “yank” from a bank n yank) weird, since it flew normal for the first portion of the flight. After the anomaly, it violently pitched up (I tried once again to level the wings) and it performed a low throttle 360 degree loop, before entering a left hand flat spin. I could do nothing about it.
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Here is a quick something from this weekend at FF'22 for the project, I saw some wonderful successes, and some mild failures. All of which informed me about this plane's capabilities for flight, and enjoyable flight at that.
2 Big Notes:
1. the C.G. on the 84" model is were the wing Leading Edge meets with the nacelle top, just in front of the nacelle bottoms at the center.
2. based on the chart below for the motors I used in the model, I was only able to bring throttl to the 50% PWM Signal. (in the top line) you will note at 50% throttle value, the motors were pulling 6.22A and only producing a hair over 1/3 of the rated top thrust value (515g/1410g) which is a thrust ratio of about 0.66:1
2 Big Notes:
1. the C.G. on the 84" model is were the wing Leading Edge meets with the nacelle top, just in front of the nacelle bottoms at the center.
2. based on the chart below for the motors I used in the model, I was only able to bring throttl to the 50% PWM Signal. (in the top line) you will note at 50% throttle value, the motors were pulling 6.22A and only producing a hair over 1/3 of the rated top thrust value (515g/1410g) which is a thrust ratio of about 0.66:1
Matthew Sanders
Elite member
I’m glad yours flew enjoyably. Mine was a handful. Maybe because the Top Gun version was purely designed to look cool, and didn’t actually go through any wind tunnel testing to see if it would be unstable.
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