I am just building fx79 with Ardupilot. First flight I used CG on those bumps and it flew OK except it would climb under power. Next flight I used the screws to set cg, so a cm or so forward of those bumps, and I had the death spiral you show in the video - managed to recover in manual mode. 3rd flight I wasn't so lucky I was in cruise mode when it started uncontrollably diving, and I didn't manage to recover. 80mph into the ground. You can imagine the outcome, starting with the liion pack ejecting itself via the nose of the plane. I actually managed to repair it, and on spotting your video, I have just ordered some cf tube to stiffen the wings. Good shout!
I fitted 10mm cf tubes as you suggested and I put the CG back to the rear of the CG bumps in the foam, and it now flies perfectly. No diving at all. Makes me think the issue is cg related. Andrew Newton recommended 100mm back along wing join line which is 10mm rear of design bumps. I would tend to agree with him.
God I just loved the part about striking the switches while quickly trying to precisely put your finger on the down elevator... I have done that SO MANY TIMES! 😂. Chris, you are an absolute genius.
Chris, wind will make zero difference. Once the aircraft is in the air it is completely unaware that there is any wind at all. There is no sudden increase in airspeed when turning into wind while flying downwind. This is a pilot-induced effect bought about by people flying models who try to maintain a constant groundspeed when flying in wind.
Great info/tips Chris... The only thing I wouldn't do is put any electrical or magnetic item on top or close to the Mini Pix. Still waiting for my Carbon Fiber rods for the wing tips. BTW I have an RC landing strip behind my home and I installed tricycle landing gear on my FX-79. Makes it a bit heavier but I think it should work OK.
I just mentioned that because you said you needed yo disable a Compass to get rid of an intermittent Compass error. Yeah I'd like to see it in action as well. It is -2 deg C today and it snowed a bit last night and the winds are gusting to ~50Kph. Will post some Video of the 1st flight if it ever warms up here.
Yes that's true, and I don't know which one I disabled :) But it has been ok like that so far. RTH can still function reasonably well without a compass.
Love the video, man! I'm setting up my own FX79 and I reinforced the outboard wing sections with the spars from a crashed Opterra much as you did because it looks so weak. Greetings from Kentucky, USA!
Interesting and well narrated vid . I discovered the TS832 vtx's several years ago and use them on all my planes . 10kms + is easy for them and having the inbuilt mic is great hey!
Well as one increase the weight, the need for a bit more reinforcements become evident, My largest FPV Wing have the entire leading edge cover with a paper thin coat of fiber glass... an "Spine Type of reinforce, nose to mid fuselage..(that it have the hook for a bungee cord) finally I use a ramp... lifter and separate from the prop as it take off... I have lost much of my youthful strength... and rather thrust a bungee than my own power... "Good idea, Rather loose ten minutes of flight than to get stock in the spin of death after one stall the aircraft.. my planes always nose dive than to start to spin... Finally a guy with a Cat... is always a signal of a good pilot!! I have two.. ;-)
The consistent patten is probably the effect of the Fresnel Zone where multipath propagation (ground bounce) successively adds to and subtracts from the level of the received signal. This is more pronounced at close range because the power of the reflection is stronger.
Have you ever thought about fabricating a kind of automatic launch rail (a little like the ones used in the V2 rockets)? You could perhaps have a dolly which accelerates it along. I'm sure this would be thoroughly entertaining....
Assuming you're not joking, how exactly would you define performance? Payload capacity? Top speed? Turning radius? Climb rate? Flight time? Distance covered per watt? Stability in wind? As for range, I think you'll find in general a larger plane can manage better range than a smaller one unless the larger one is somehow very inefficient, but this and the Z-84 are basically the same design.
Chris: You should try the autoLaunch, maybe on another plane (if you're nervous about trying it on this one), I think you would be happy with it. To do INAV autolaunch, turn on the autolaunch switch first, then the Arm switch, then adjust the throttle (I use about 3/4, prop Won't spin), then just throw it nice and level like in your video, the prop won't start until it's out of your hand, it's a great feature of INAV and works well.
Yeah, a pretty nice plane. Just don't push it too fast, unless you've done something about the softish wingtips. They're quite tough, having a such a big lump of foam along the front: th-cam.com/video/jBKlqqLYMRc/w-d-xo.html
I've put all the mods onto my wing and first flight great, the only thing it comes in like a bat out of hell, I've read that fitting the flaps up can make it dive down to quick, any info you can give me would be great.
nice vid. *que a much longer winded explanation* Had a suggestion related to my comment on the other video i think the control characteristics you are still seeing are still related to the problem i mentioned. if you look at your elevons they are tapered where they meet the vertical stabilizer but not on the wing tip section which is thinner and flexs more and since it is constrained on one side it will flex back in an ark tucking that sharp corner of the tip section(red section) into the elevon and either just pinching which the stiffening you did probably reduces the force it pinches so that the servo can over power it in level flight or minor corrections but if you or the ardupilot makes a large correction you can kinda see it happening in the video where the tip of the elevon gets stuck up or down untill the wingtip flexes back out from under or over the elevon. Easiest correction i can see that is probably a five minute fix would be to taper that gap between the wingtip and the elevon even just 4-5 degrees will probably fix the problem. If i'm right about the cause of your problems you would probably feel it as even now the controls being sluggish, when you make a turn or bank it feels slow to come out of it even for the large frame and relatively slow flying speeds. Then in the extreme cases it would feel like the controls are locked until it slows down enough to release and then it is fully controllable again. when i tried to explain in the other video i don't think i was saying what i meant well enough.
I'm not sure if I'm following what you're saying, but if you mean the bending of the wingtip would cause the elevon to bend down, yes that's something I considered. The new spar should prevent that though, and it doesn't explain why the nose down starts (only why it persists once started).
Basically the tip section can't go straight back it will go back and in towards the center. This drives the sharp corner where it meets the elevon into the elevon and forces that end of the elevon either up or down. And restricts the movement till the flex releases the elevon. It would make more sense if I could draw it I may try to message a diagram but basically to stop it you would have to taper the elevon on the outside edge or the tip section where it meets the elevon
Well as you say the gap there is extremely small, so I'll cut it a bit wider. But it seems to me that it would take a huge amount of bend across a very short distance for it to bind up.
Let me know how it goes it should take away the last of your control characteristics. The flex doesn't have to be much and that far from the servo it has huge advantage .
Anthony Williams after reading your discussion here with Chris, you've convinced me of an issue that I thought may have been happening with a couple of my foam models recently. It has totally justified the similar fix I applied to one of them, by increasing the gap between the elevon and the trailing edge of the tip section that holds the winglets. Because of this binding causing the elevon to lock in an abnormal position either up or down therefore it lost roll control, especially when large aerodynamic side loads were placed on the winglets. The other model which spun in on it's maiden, I believe may of had a similar issue due to wing flex in foam and because of its small scale size and knife slice cuts seperating aileron and tip, afforded no relief and bound the aileron into an uncontrollable constant roll leading to it flipping over and crashing from low altitude. Furthermore I must thank Chris for a very insightful video he has made here and yourself for confirming that this is a very real issue pertaining to foam more than other types of build materials.
Very informative! But what happened to your ASW28? Never saw follow-ups on this. Would this not be a platform for the MiniPix too, at least as flight assist system?
Not quite sure what you are expecting, but I did post a couple more videos after the first one: th-cam.com/video/-rKZYawqRuU/w-d-xo.html th-cam.com/video/umCMVPi8cNg/w-d-xo.html
Regarding the components getting too hot while inside: Has anyone tried sticking a strip of "aluminium tape" to the hot component with a thermal glue or pad, and then running the other end of the tape along the plane's outer skin? It might be a workable way of passively cooling stuff.
ON FULL THROTLE YOU HAVE ELEVON DOWN ''MOSTLY'' BECAUSE OF 1.6KG WEAK ANALOG ''EMAX'' SERVOS USE THE 12.5G DIGITAL M/G SERVOS ''EMAX'' 2.4/2.8KG PUT ONE CARBON SPARE ALSO.HOPE I HELP!!
Depends how much whisky I had before breakfast. hah, seriously though, I had to look up what that means. I don't think so, but sometimes when I'm focusing on doing something carefully, usually soldering, I can get a shake going - very annoying. My left hand got pretty crushed in a motorbike crash once, the little finger had a fracture and the nail was completely torn out. Even now it feels a bit odd to hold my left hand in certain precise positions.
I got it from Banggood: goo.gl/X9xCdp You'll still need servos, ESC, motor etc. I mentioned a bit about what I used in the first video I made about this plane here: th-cam.com/video/z2rgomjhUdk/w-d-xo.html
![[DRIP] ‘BILLIONAIRE’ PREVIEW](http://i.ytimg.com/vi/m0eXQD0gIeE/mqdefault.jpg)
I forgot to mention about CG position, I have it about 1cm forward of those little bumps that mark the 'official' position.
I am just building fx79 with Ardupilot. First flight I used CG on those bumps and it flew OK except it would climb under power. Next flight I used the screws to set cg, so a cm or so forward of those bumps, and I had the death spiral you show in the video - managed to recover in manual mode. 3rd flight I wasn't so lucky I was in cruise mode when it started uncontrollably diving, and I didn't manage to recover. 80mph into the ground. You can imagine the outcome, starting with the liion pack ejecting itself via the nose of the plane.
I actually managed to repair it, and on spotting your video, I have just ordered some cf tube to stiffen the wings. Good shout!
I fitted 10mm cf tubes as you suggested and I put the CG back to the rear of the CG bumps in the foam, and it now flies perfectly. No diving at all. Makes me think the issue is cg related. Andrew Newton recommended 100mm back along wing join line which is 10mm rear of design bumps. I would tend to agree with him.
God I just loved the part about striking the switches while quickly trying to precisely put your finger on the down elevator... I have done that SO MANY TIMES! 😂. Chris, you are an absolute genius.
Chris, wind will make zero difference. Once the aircraft is in the air it is completely unaware that there is any wind at all. There is no sudden increase in airspeed when turning into wind while flying downwind. This is a pilot-induced effect bought about by people flying models who try to maintain a constant groundspeed when flying in wind.
If the autopilot is trying to maintain a constant groundspeed would it not be the same though?
Good video, thanks! I'm getting ready to get this wing, so your tips will come in very handy.
Great info/tips Chris...
The only thing I wouldn't do is put any electrical or magnetic item on top or close to the Mini Pix. Still waiting for my Carbon Fiber rods for the wing tips.
BTW I have an RC landing strip behind my home and I installed tricycle landing gear on my FX-79.
Makes it a bit heavier but I think it should work OK.
There is a compass in the GPS bit if that's what you're worried about. It would be cool to see a video of your landing gear in action sometime :)
I just mentioned that because you said you needed yo disable a Compass to get rid of an intermittent Compass error.
Yeah I'd like to see it in action as well. It is -2 deg C today and it snowed a bit last night and the winds are gusting to ~50Kph.
Will post some Video of the 1st flight if it ever warms up here.
Yes that's true, and I don't know which one I disabled :) But it has been ok like that so far. RTH can still function reasonably well without a compass.
If I have the same Compass errors I'll disable one as well.
Love the video, man! I'm setting up my own FX79 and I reinforced the outboard wing sections with the spars from a crashed Opterra much as you did because it looks so weak. Greetings from Kentucky, USA!
I did all your tips, it flies great, stopping is another matter, it has the ground effect, so I fitted airbrakes I can get it down easy now.
Interesting and well narrated vid . I discovered the TS832 vtx's several years ago and use them on all my planes . 10kms + is easy for them and having the inbuilt mic is great hey!
Running an airspeed sensor would help the autopilot not to overspeed in head winds
Well as one increase the weight, the need for a bit more reinforcements become evident, My largest FPV Wing have the entire leading edge cover with a paper thin coat of fiber glass... an "Spine Type of reinforce, nose to mid fuselage..(that it have the hook for a bungee cord) finally I use a ramp... lifter and separate from the prop as it take off... I have lost much of my youthful strength... and rather thrust a bungee than my own power... "Good idea, Rather loose ten minutes of flight than to get stock in the spin of death after one stall the aircraft.. my planes always nose dive than to start to spin... Finally a guy with a Cat... is always a signal of a good pilot!! I have two.. ;-)
The consistent patten is probably the effect of the Fresnel Zone where multipath propagation (ground bounce) successively adds to and subtracts from the level of the received signal. This is more pronounced at close range because the power of the reflection is stronger.
Have you ever thought about fabricating a kind of automatic launch rail (a little like the ones used in the V2 rockets)? You could perhaps have a dolly which accelerates it along. I'm sure this would be thoroughly entertaining....
I think Z-84 has better performance and range that this wing. Thanks for your video, very informative!
Assuming you're not joking, how exactly would you define performance? Payload capacity? Top speed? Turning radius? Climb rate? Flight time? Distance covered per watt? Stability in wind? As for range, I think you'll find in general a larger plane can manage better range than a smaller one unless the larger one is somehow very inefficient, but this and the Z-84 are basically the same design.
Chris: You should try the autoLaunch, maybe on another plane (if you're nervous about trying it on this one), I think you would be happy with it. To do INAV autolaunch, turn on the autolaunch switch first, then the Arm switch, then adjust the throttle (I use about 3/4, prop Won't spin), then just throw it nice and level like in your video, the prop won't start until it's out of your hand, it's a great feature of INAV and works well.
Yes, I tried it on my 1.2m wing: th-cam.com/video/3SAh0EvRgRg/w-d-xo.html
I forgot about that video- it worked great.
Hi,
Nice mods and tips - thanks!
Can you still recommend the FX79 ?
I'm thinking of buying one myself :)
Yeah, a pretty nice plane. Just don't push it too fast, unless you've done something about the softish wingtips. They're quite tough, having a such a big lump of foam along the front: th-cam.com/video/jBKlqqLYMRc/w-d-xo.html
Thank you for the launch tips. Will be trying them next time
I've put all the mods onto my wing and first flight great, the only thing it comes in like a bat out of hell, I've read that fitting the flaps up can make it dive down to quick, any info you can give me would be great.
nice vid. *que a much longer winded explanation* Had a suggestion related to my comment on the other video i think the control characteristics you are still seeing are still related to the problem i mentioned. if you look at your elevons they are tapered where they meet the vertical stabilizer but not on the wing tip section which is thinner and flexs more and since it is constrained on one side it will flex back in an ark tucking that sharp corner of the tip section(red section) into the elevon and either just pinching which the stiffening you did probably reduces the force it pinches so that the servo can over power it in level flight or minor corrections but if you or the ardupilot makes a large correction you can kinda see it happening in the video where the tip of the elevon gets stuck up or down untill the wingtip flexes back out from under or over the elevon. Easiest correction i can see that is probably a five minute fix would be to taper that gap between the wingtip and the elevon even just 4-5 degrees will probably fix the problem. If i'm right about the cause of your problems you would probably feel it as even now the controls being sluggish, when you make a turn or bank it feels slow to come out of it even for the large frame and relatively slow flying speeds. Then in the extreme cases it would feel like the controls are locked until it slows down enough to release and then it is fully controllable again. when i tried to explain in the other video i don't think i was saying what i meant well enough.
I'm not sure if I'm following what you're saying, but if you mean the bending of the wingtip would cause the elevon to bend down, yes that's something I considered. The new spar should prevent that though, and it doesn't explain why the nose down starts (only why it persists once started).
Basically the tip section can't go straight back it will go back and in towards the center. This drives the sharp corner where it meets the elevon into the elevon and forces that end of the elevon either up or down. And restricts the movement till the flex releases the elevon. It would make more sense if I could draw it I may try to message a diagram but basically to stop it you would have to taper the elevon on the outside edge or the tip section where it meets the elevon
Well as you say the gap there is extremely small, so I'll cut it a bit wider. But it seems to me that it would take a huge amount of bend across a very short distance for it to bind up.
Let me know how it goes it should take away the last of your control characteristics. The flex doesn't have to be much and that far from the servo it has huge advantage .
Anthony Williams after reading your discussion here with Chris, you've convinced me of an issue that I thought may have been happening with a couple of my foam models recently.
It has totally justified the similar fix I applied to one of them, by increasing the gap between the elevon and the trailing edge of the tip section that holds the winglets. Because of this binding causing the elevon to lock in an abnormal position either up or down therefore it lost roll control, especially when large aerodynamic side loads were placed on the winglets.
The other model which spun in on it's maiden, I believe may of had a similar issue due to wing flex in foam and because of its small scale size and knife slice cuts seperating aileron and tip, afforded no relief and bound the aileron into an uncontrollable constant roll leading to it flipping over and crashing from low altitude.
Furthermore I must thank Chris for a very insightful video he has made here and yourself for confirming that this is a very real issue pertaining to foam more than other types of build materials.
Great Video, not many big bird setups around these times...
Very informative!
But what happened to your ASW28? Never saw follow-ups on this.
Would this not be a platform for the MiniPix too, at least as flight assist system?
Not quite sure what you are expecting, but I did post a couple more videos after the first one:
th-cam.com/video/-rKZYawqRuU/w-d-xo.html
th-cam.com/video/umCMVPi8cNg/w-d-xo.html
Yea, you should definitely keep those minim osds cool, I've had a couple break on me because of them over heating.
What software tool/methods did you use to create that stitched together image? do you have a vid on that cheers
Excellent video.
Love your cat!
Regarding the components getting too hot while inside:
Has anyone tried sticking a strip of "aluminium tape" to the hot component with a thermal glue or pad, and then running the other end of the tape along the plane's outer skin? It might be a workable way of passively cooling stuff.
ON FULL THROTLE YOU HAVE ELEVON DOWN ''MOSTLY'' BECAUSE OF 1.6KG WEAK ANALOG ''EMAX'' SERVOS USE THE 12.5G DIGITAL M/G SERVOS ''EMAX'' 2.4/2.8KG PUT ONE CARBON SPARE ALSO.HOPE I HELP!!
Thanks for the informative videos as always :) , will you try bungee launchers at some point ?
I was thinking about it, but now that I have a reasonably reliable hand-launch, probably not.
Have you tried auto takeoff on your wing?
Not on this one, but yes th-cam.com/video/3SAh0EvRgRg/w-d-xo.html
22:48 I mentioned here why I don't use it...
EXCELENTE!!!
Do you have essential tremors?
Depends how much whisky I had before breakfast.
hah, seriously though, I had to look up what that means. I don't think so, but sometimes when I'm focusing on doing something carefully, usually soldering, I can get a shake going - very annoying. My left hand got pretty crushed in a motorbike crash once, the little finger had a fracture and the nail was completely torn out. Even now it feels a bit odd to hold my left hand in certain precise positions.
2:01 What was that?! the other wing?!
The lid/cover piece.
Oh right. What cause it to suddenly roll like that then? Or was that you trying to bail out?
It's pitching not rolling, the cameras are mounted in the middle looking out toward the wingtips.
Link to this wing please.
I got it from Banggood: goo.gl/X9xCdp
You'll still need servos, ESC, motor etc. I mentioned a bit about what I used in the first video I made about this plane here: th-cam.com/video/z2rgomjhUdk/w-d-xo.html
You do not know what you want (need) !