FTFC19 Tron Legacy One-Man Light Jet by DamoRC
- Thread starter DamoRC
- Start date
Damage report:
Left battery pod totally off - I must remember to return that divot to the field.
There is a crack in the left pylon at the v-tail.
Right pylon totally off, just held on with the wires.
All of this is repairable I think.
Here is a gif of the second launch
Looking at this in slow-mo I am beginning to thing that this is just a lack of power problem (oh, and I could have tried a little harder, the throw seems a little timid).
Yep - although I like to maiden nose heavy, I may have overdone it this time. On the thrust angle, this is a profile pic marking the supposed thrust line from the EDF (horizontal line) and the CG position, which is essentially where I am gripping the model for launch. I would not expect to be able to feel "push over" from the EDF with this setup which I why I suspect that the EDF and thrust tube could be off, with the thrust exiting the tube pointing downward, creating a torque around the CG. But looking at the vid of the second launch, I may be imagining this because the plane didn't look like it was nosing down significantly.
Yep - this could be a good option - lack of launch speed is probably killing any attempt to get her up. Only concern is that once up, if I am still significantly underpowered, then I just come down again.
Given that I have no idea if this shape / configuration will fly but I do know that it is significantly underpowered, and the fact that I can't really change the former, but can do a lot with the latter, I think the next step is to add gobs of thrust. Options for this are:
(a) Add 2 x NTM2826 1200Kv motors wearing 8x4.5 props to the front of the battery pods - these can run off the same 4S supply as the EDF and provide 5 lbs (!) of extra thrust
(b) Remove the EDF and add the motors described in (a)
(c) Remove the EDF and add a single pusher to the rear ( the E-Flite Motor 10 that I run on the Tigercat will give me just under 4.5 lbs thrust on 3S with a 12x4 prop).
It also might be worth my while, if I pull the EDF, to do some glide testing.
Left battery pod totally off - I must remember to return that divot to the field.
There is a crack in the left pylon at the v-tail.
Right pylon totally off, just held on with the wires.
All of this is repairable I think.
Here is a gif of the second launch
Looking at this in slow-mo I am beginning to thing that this is just a lack of power problem (oh, and I could have tried a little harder, the throw seems a little timid).
Yep - although I like to maiden nose heavy, I may have overdone it this time. On the thrust angle, this is a profile pic marking the supposed thrust line from the EDF (horizontal line) and the CG position, which is essentially where I am gripping the model for launch. I would not expect to be able to feel "push over" from the EDF with this setup which I why I suspect that the EDF and thrust tube could be off, with the thrust exiting the tube pointing downward, creating a torque around the CG. But looking at the vid of the second launch, I may be imagining this because the plane didn't look like it was nosing down significantly.
Yep - this could be a good option - lack of launch speed is probably killing any attempt to get her up. Only concern is that once up, if I am still significantly underpowered, then I just come down again.
Given that I have no idea if this shape / configuration will fly but I do know that it is significantly underpowered, and the fact that I can't really change the former, but can do a lot with the latter, I think the next step is to add gobs of thrust. Options for this are:
(a) Add 2 x NTM2826 1200Kv motors wearing 8x4.5 props to the front of the battery pods - these can run off the same 4S supply as the EDF and provide 5 lbs (!) of extra thrust
(b) Remove the EDF and add the motors described in (a)
(c) Remove the EDF and add a single pusher to the rear ( the E-Flite Motor 10 that I run on the Tigercat will give me just under 4.5 lbs thrust on 3S with a 12x4 prop).
It also might be worth my while, if I pull the EDF, to do some glide testing.
jfaleo1
Junior Member
Add the two motors and go for it. What is there to lose😀
About the pushover. I had the same feel on launching the Quinjet but it turned out to be of no consequence. On that model my EDFs are above center line a lot and are still zero thrust angle, so I did expect it but it did not nose over at all. I don’t think that looks like an issue for you either. Seems to me a ground/bungee start to get airspeed, or more power is needed. A higher lift airfoil may help or possibly flaps to increase camber until you are up to speed.
About the pushover. I had the same feel on launching the Quinjet but it turned out to be of no consequence. On that model my EDFs are above center line a lot and are still zero thrust angle, so I did expect it but it did not nose over at all. I don’t think that looks like an issue for you either. Seems to me a ground/bungee start to get airspeed, or more power is needed. A higher lift airfoil may help or possibly flaps to increase camber until you are up to speed.
Namactual
Elite member
That is a sound plan. Same with the prop power.
Looking at the launch, it looked like it may have yaw'd a bit from the toss. I agree that it does not look to be a thrust angle nose down, I would say the issue is the awkwardness of the grip. I also agree that having a better T2WR, it probably would have powered out of that.
Not a bad toss, just not enough thrust combined with an awkward grip.
Build post is complete (what a job that was, its a bit of a slog to read through, sorry).
Haven't made much progress with the plane. I did pull the EDF because the next version will be prop powered. Not overly happy with this option as I think the props will not really fit the look of the plane. One option is twin props at the front of the battery pods - this might give me the option to mount the battery in the fuse instead of in the pods and, if I can keep it to 1 x 2200mAh 4S, this will save 1/2 pound. Second option is a single powerful pusher. I have the motors and props for this, but I might have trouble getting the plane to balance if I hang a large motor on the rear end. I'll do some mockups once I fix the airframe.
Haven't made much progress with the plane. I did pull the EDF because the next version will be prop powered. Not overly happy with this option as I think the props will not really fit the look of the plane. One option is twin props at the front of the battery pods - this might give me the option to mount the battery in the fuse instead of in the pods and, if I can keep it to 1 x 2200mAh 4S, this will save 1/2 pound. Second option is a single powerful pusher. I have the motors and props for this, but I might have trouble getting the plane to balance if I hang a large motor on the rear end. I'll do some mockups once I fix the airframe.
Quick update
The repairs are pretty much done. She's a little rough (and probably a little fragile) but good to go I think. With the airframe back together I did some mockups of a pusher configuration (I really want to avoid twin motors at the front from an aesthetics viewpoint). Looks like I can get the E-Flite Power 15 950Kv motor ("borrowed" from the Gee Bee R3) hung on the back and get her balanced with the twin 4S batts in the front. With this setup she'll be a tad over 4 pounds. On the Gee Bee, this motor wears a 9x9 prop for speed. But for the Light Jet, all I care about is raw thrust so I put the motor on the thrust stand and tested a few props on 4S. Used 2 x 2200mAh 4S in parallel to mimic the available power and ran tests to cover 50%, 75%, and 100% throttle. Increased the prop size (limited by what I have on hand) until I started to hit 40A-ish
Results at 100% Throttle
So the 11 x 6 is really tempting at almost 5.5 pounds but I am going to have to check what the prop overhang at the back will be. I think she will still be a handful to launch and if I can avoid ripping my knuckles to shreds with the pusher prop that would be nice. Also considering a couple of fins attached to the underside of the tail that would hit the back of my hand before the prop does.
The repairs are pretty much done. She's a little rough (and probably a little fragile) but good to go I think. With the airframe back together I did some mockups of a pusher configuration (I really want to avoid twin motors at the front from an aesthetics viewpoint). Looks like I can get the E-Flite Power 15 950Kv motor ("borrowed" from the Gee Bee R3) hung on the back and get her balanced with the twin 4S batts in the front. With this setup she'll be a tad over 4 pounds. On the Gee Bee, this motor wears a 9x9 prop for speed. But for the Light Jet, all I care about is raw thrust so I put the motor on the thrust stand and tested a few props on 4S. Used 2 x 2200mAh 4S in parallel to mimic the available power and ran tests to cover 50%, 75%, and 100% throttle. Increased the prop size (limited by what I have on hand) until I started to hit 40A-ish
Results at 100% Throttle
Prop | Thrust (lbs) | Current (A) | Power Input (W) | RPM |
9 x 9 | 3.35 | 43.4 | 651 | 10684 |
9 x 6 | 3.83 | 31.2 | 477 | 12000 |
10 x 6 | 4.51 | 32.4 | 486 (est) | 11830 |
11 x 6 | 5.49 | 39.6 | 590 | 11029 |
So the 11 x 6 is really tempting at almost 5.5 pounds but I am going to have to check what the prop overhang at the back will be. I think she will still be a handful to launch and if I can avoid ripping my knuckles to shreds with the pusher prop that would be nice. Also considering a couple of fins attached to the underside of the tail that would hit the back of my hand before the prop does.
So, maiden flight - take 3 this weekend?
That's the plan.
Is it a bird? Is it a plane? Is it a Tron Legacy Light Jet flying?
Well, actually, no, its not.
If you put 5 pounds of thrust on a 4 pound plane and launch it at 45 degrees it has very little choice in the matter of whether it gets propelled upwards or not. Flying - kinda sorta - but not really. Shortly after this pic she pitched up hard, banked hard to the left and headed towards terra firma. I applied the appropriate control input by nearly ripping my elevator stick out of the transmitter, and one of the pylon joints failed, folding the wings which were apparently needed for sustained flight. Note the dihedral angle has increased significantly in this next pic....
So there it is. She's done. I will not attempt to fix this but I have learned a lot and think that I can still build a viable model of this plane - this time cutting down many carbon fiber trees to use the branches in the build. There will be a tragic montage video (design, build, crash, crash again) but beyond that I believe that this entry is complete. @rockyboy - if its okay with you, I will not be finalizing and posting the plans for this for the entry as I couldn't in good conscience encourage anyone to try this version. Maybe the next one.
DamoRC
Well, actually, no, its not.
If you put 5 pounds of thrust on a 4 pound plane and launch it at 45 degrees it has very little choice in the matter of whether it gets propelled upwards or not. Flying - kinda sorta - but not really. Shortly after this pic she pitched up hard, banked hard to the left and headed towards terra firma. I applied the appropriate control input by nearly ripping my elevator stick out of the transmitter, and one of the pylon joints failed, folding the wings which were apparently needed for sustained flight. Note the dihedral angle has increased significantly in this next pic....
So there it is. She's done. I will not attempt to fix this but I have learned a lot and think that I can still build a viable model of this plane - this time cutting down many carbon fiber trees to use the branches in the build. There will be a tragic montage video (design, build, crash, crash again) but beyond that I believe that this entry is complete. @rockyboy - if its okay with you, I will not be finalizing and posting the plans for this for the entry as I couldn't in good conscience encourage anyone to try this version. Maybe the next one.
DamoRC
Is it a bird? Is it a plane? Is it a Tron Legacy Light Jet flying?
View attachment 124664
Well, actually, no, its not.
If you put 5 pounds of thrust on a 4 pound plane and launch it at 45 degrees it has very little choice in the matter of whether it gets propelled upwards or not. Flying - kinda sorta - but not really. Shortly after this pic she pitched up hard, banked hard to the left and headed towards terra firma. I applied the appropriate control input by nearly ripping my elevator stick out of the transmitter, and one of the pylon joints failed, folding the wings which were apparently needed for sustained flight. Note the dihedral angle has increased significantly in this next pic....
View attachment 124666
So there it is. She's done. I will not attempt to fix this but I have learned a lot and think that I can still build a viable model of this plane - this time cutting down many carbon fiber trees to use the branches in the build. There will be a tragic montage video (design, build, crash, crash again) but beyond that I believe that this entry is complete. @rockyboy - if its okay with you, I will not be finalizing and posting the plans for this for the entry as I couldn't in good conscience encourage anyone to try this version. Maybe the next one.
DamoRC
That first picture is awesome! She looks so majestic in the air!
Too bad she doesn't want to stay there
Completely understand not wanting to post plans for a complicated lawn dart (too soon?)
Seriously though - great looking build and a whole lot of learning - well done sir!
That first picture is awesome! She looks so majestic in the air!
Too bad she doesn't want to stay there
Completely understand not wanting to post plans for a complicated lawn dart (too soon?)
Seriously though - great looking build and a whole lot of learning - well done sir!
Thanks Man!
I think I will skip finalizing the video production given that its mostly designing and building a plane that never flew. Instead, I post this gif as my "proof of flight" video.
TheSFReader
Member
Ditto ! Great build !
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