Easy fix. Lots of fun though. Drove the nighthawks absolutely nuts.
*Unofficial* FT Goblin
- Thread starter SP0NZ
- Start date
Fun build, can't wait to maiden it. 2205 2300 or 2600kv, can't Remember. 20a esc, balances with a 2200 3s.
The cg is very finicky tho, move the battery like an inch and it goes from tail heavy to nose heavy. Definitely gotta mark the battery position.
The cg is very finicky tho, move the battery like an inch and it goes from tail heavy to nose heavy. Definitely gotta mark the battery position.
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A 6045 prop works great for 3s with that motor, or the regular f pack and has no problem fitting between the vstabs.
jpot1
Elite member
I try to build all of my FT planes as swappable as I only have a few motors/escs even if it means tweaking the design. It looks like 0 thrust angle so do you think there would be any problem cutting out a bit of the wing (would be hidden in the fuse anyway) so a mini power pod could be used. It looks like the rear opening would accommodate it. Thoughts?
kilroy07
Legendary member
"Maybe" a mini would fit without too much trouble (such as from the sparrow?)
There are fusalage doublers and the wing makes that area pretty tight... though.
I might suggest using the bottom piece and setting it up as a flap/door (by just gluing the front end.)
That way you could just use an Allen wrench to unscrew the motor to swap it out... have to fish around with the esc I guess...
Either way might work... I would build the fuselage bits first if I were you so you can play around with the fit of the pod.
(In the flight/intro video they indicated that where the thrust line was pretty critical it how it flew.)
This just might end up a dedicated build...
Good Luck!
basslord1124
Master member
Just watched the video for this one. Man they are starting to crank out some designs again...cool!
jpot1
Elite member
"Maybe" a mini would fit without too much trouble (such as from the sparrow?)
There are fusalage doublers and the wing makes that area pretty tight... though.
I might suggest using the bottom piece and setting it up as a flap/door (by just gluing the front end.)
That way you could just use an Allen wrench to unscrew the motor to swap it out... have to fish around with the esc I guess...
Either way might work... I would build the fuselage bits first if I were you so you can play around with the fit of the pod.
(In the flight/intro video they indicated that where the thrust line was pretty critical it how it flew.)
This just might end up a dedicated build...
Good Luck!
Thanks kilroy7, for grins pulled the internal fuse section into Inkscape and it measures out at 1.27" which should be perfect for the mini pod associated with my FT arrow which measures 1.22".
Forgot to post last night. Flew with the 2306 2400kv, a Dalprop 5045 Blunt nose Triblade, and a 2200mah 3 cell battery for exactly 15 minutes last night. I flew a mix of throttle settings, kinda like the first video posted. Some full throttle chasing the hawks and cars.
Final voltage was 3.75 per cell, so a bit lower than I typically like to go. I'd say 12 minutes is probably a good time to land with this combo.
Final voltage was 3.75 per cell, so a bit lower than I typically like to go. I'd say 12 minutes is probably a good time to land with this combo.
jaredstrees
Well-known member
Finished her up last night. Just need to put a little color on the wings for orientation and we are good to go. Oh and a prop! Very easy build. From plans to plane one of the easiest most intuitive designs yet. Hope she flies as easy as she built!
Hai-Lee
Old and Bold RC PILOT
My question is to seep clarification of your pitch authority comment. Is it that you have too much authority or too little.
As the design is stall resistant it is possible to maintain full up elevator in level flight if you are trying to land too slowly. So if you are running out of elevator then either land a little faster or fly with the balance point slightly forward of the stated CG, (very marginally only). This will cause the nose of the plane to bounce up and down at stall and give you a visible indication that you are flying too slowly.
Secondly with a large balance weight, (battery) far forward the upwards forces applied by the elevator are somewhat limited as very little aerodynamic forces will be required to dip the nose but considerable forces will be required to lift it. as the speed is reduced this asymmetry can become very noticeable. Normally I ensure that I use a good amount of elevon differential and it behaves better.
Just things I discovered with my TTW version which is extremely similar.
Have fun!
mrjdstewart
Legendary member
whats happening? not enough elevator movement? not enough servo torque to use movement? or just too short of a plane, making it pitchy to start with?
i have the plans and need to take into inkscape. i figured i'd do it as a lesson for my students so it may be a few weeks before i can work it in, but i really want to build/fly this one. i think it has good potential for combat as well as just stupid speed, which i'm always a fan of.
laters,
me
kilroy07
Legendary member
Sorry, I should have provided more info.
I put a 2200 3s in the nose and it balanced just fine (it does go from nose to tail in about a half an inch however.)
When I tossed her into the air, she leveled out then slowly sank to the ground under full power.
I added some up trim and launched again, while she flew I was using almost all back pressure to keep her level. I made the mistake of getting her in a nose up attitude, she looped then did not come out of the dive...
I watched the build video again to see if the elevons should be set with some up incidence (is that called reflex?) but they state to build with them level (inline) with the wings...
So I am a bit perplexed... was just wondering if anyone has had issues or, if it were just me (it's probably me...)
Third time's the charm, right?
I put a 2200 3s in the nose and it balanced just fine (it does go from nose to tail in about a half an inch however.)
When I tossed her into the air, she leveled out then slowly sank to the ground under full power.
I added some up trim and launched again, while she flew I was using almost all back pressure to keep her level. I made the mistake of getting her in a nose up attitude, she looped then did not come out of the dive...
I watched the build video again to see if the elevons should be set with some up incidence (is that called reflex?) but they state to build with them level (inline) with the wings...
So I am a bit perplexed... was just wondering if anyone has had issues or, if it were just me (it's probably me...)
Third time's the charm, right?
Hai-Lee
Old and Bold RC PILOT
May I ask what the AUW was? With the motor specified it should almost explode out of your hand in acceleration and flying should be no problem.Sorry, I should have provided more info.
I put a 2200 3s in the nose and it balanced just fine (it does go from nose to tail in about a half an inch however.)
When I tossed her into the air, she leveled out then slowly sank to the ground under full power.
I added some up trim and launched again, while she flew I was using almost all back pressure to keep her level. I made the mistake of getting her in a nose up attitude, she looped then did not come out of the dive...
I watched the build video again to see if the elevons should be set with some up incidence (is that called reflex?) but they state to build with them level (inline) with the wings...
So I am a bit perplexed... was just wondering if anyone has had issues or, if it were just me (it's probably me...)
Third time's the charm, right?
I also wonder if when you put it into a climb if the battery slipped and upset the balance and hence lost control response.
When you get it flying, (or your next version), try to get it up to reasonable height and try to stall it. If it wanders around and then drops a wing it is too tail heavy and if it bounces it nose up and down severely it is too nose heavy!
Have fun!
Sorry, I should have provided more info.
I put a 2200 3s in the nose and it balanced just fine (it does go from nose to tail in about a half an inch however.)
When I tossed her into the air, she leveled out then slowly sank to the ground under full power.
I added some up trim and launched again, while she flew I was using almost all back pressure to keep her level. I made the mistake of getting her in a nose up attitude, she looped then did not come out of the dive...
I watched the build video again to see if the elevons should be set with some up incidence (is that called reflex?) but they state to build with them level (inline) with the wings...
So I am a bit perplexed... was just wondering if anyone has had issues or, if it were just me (it's probably me...)
Third time's the charm, right?
You don't have your prop on backwards do you?
As for reflex, yes it does need some. After building mine, I asked Andres about reflex, and he said to give it about a foamboards thickness worth. I believe that's what Dan put into the plans.
I started out with about that much, but discovered it needed a bit more for level flight at cruising speed. I've attached a picture of my current reflex amount.
You'll also probably want to increase the elevator throws. This plane is far more roll than pitch sensitive for the same amount of travel. I set pitch rates around 30% higher than roll.
I haven't watched the build video, but if they forgot to mention it, the video probably needs to be tweaked, or have a note added. A flying wing with this style airfoil is not going to work without reflex.
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kilroy07
Legendary member
Not THIS time!I bet the issue is reflex!
I've built both the arrow and spear and they both had some reflex, I thought I was odd the Goblin did not.
Ah, yes I see that now, Thanks!!
The video is wrong however 15:35.
I'll build the third one tonight and try again.
Thanks everyone for the help!
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