1 Sheet Plane
- Thread starter Mad_Mechanic
- Start date
CapnBry
Elite member
Looks great, @Mad_Mechanic! I build things really fast but make up for it by spending three times as long as everyone else putting in the servos, horns, and pushrods. I really want to get some of those smaller servos now though. I had so much fun flying your plane that I wonder why I build so many bigger models.
I'm not sure you'd want to push the wing back further, since it would shorten the tail moment and reduce the control and stability effectiveness. On the beta plans there's 25mm between the fuse and the horizontal stabilizer, so why not just add 20mm to the nose and shift it all up? My balance problems might just be due to using heavier servos and the smaller battery (your 1300mAh easily weighs the 10g needed more than my 950mAh). If my math checks out, the moment of adding the 10g to the nose would be eliminated if I could just move the motor, battery, 12A EMAX ESC, and receiver forward by 15mm. Hey, I've got an idea, I might just add on a short 15mm bit to give it a try.
I'm not sure you'd want to push the wing back further, since it would shorten the tail moment and reduce the control and stability effectiveness. On the beta plans there's 25mm between the fuse and the horizontal stabilizer, so why not just add 20mm to the nose and shift it all up? My balance problems might just be due to using heavier servos and the smaller battery (your 1300mAh easily weighs the 10g needed more than my 950mAh). If my math checks out, the moment of adding the 10g to the nose would be eliminated if I could just move the motor, battery, 12A EMAX ESC, and receiver forward by 15mm. Hey, I've got an idea, I might just add on a short 15mm bit to give it a try.
Mad_Mechanic
Well-known member
This is the best time for experimentation. If we can tweak things to turn this plane into something that is more new flyer friendly and easier to balance all the better!
CapnBry
Elite member
I think with the rudder you could just extend the front of the v-stab forward 5mm, and extend the line until it gets to the same point the old one did like this:
That increases the whole v-stab, but it makes the control surface area about 15% bigger without requiring any other changes-- the tab just extends over the fuselage slightly. That should be enough. It's pretty close now, but you see when I go vertical and go full rudder it doesn't quite have the authority to flip around. The 15% should make up that difference.
That increases the whole v-stab, but it makes the control surface area about 15% bigger without requiring any other changes-- the tab just extends over the fuselage slightly. That should be enough. It's pretty close now, but you see when I go vertical and go full rudder it doesn't quite have the authority to flip around. The 15% should make up that difference.
Mad_Mechanic
Well-known member
Simple enough modification, should not be an issue.
Mad_Mechanic
Well-known member
Tweaked the Rudder, here is what is looks like on the foamboard layout compared to the original.
Mad_Mechanic
Well-known member
CapnBry
Elite member
I happened to have a strip of scrap that was 20.1mm so I used that instead of 15mm. Model now balances at 32-33mm without the 10g up front, perfect! I'd hold off on making that change until you've got your setup all balanced and can tell that my setup isn't just way off. I took it out and flew it real quick (I don't know what I'd do if I didn't have a park just half a mile down the road). Flies just as good, but now with 5% more thrust to weight. You can tell by my nose that I definitely need more thrust right? Someone's gotta show the ground who's boss.
The rudder I just sort of faked by adding a 14mm strip to the top of my rudder. Now when I go full rudder I can see the back of the plane kick out so it is working good. I even tried to do some knife edge, but 1) I can't 2) not quite the model for knife edges. It does better than a tiny tranier though. Overall I'd say this is a great easy design that costs very little and the build is super easy. All straight lines makes it easy to cut and the low part count means only a few cuts. It's definitely much more aerobatic than a tiny trainer but doesn't go quite as slow, although this feels more maneuverable on its low end.
Don't forget, I also cut ~1.77mm off the right side of the nose then angled the top/bottom to link the sides to give it ~2 degrees of right thrust. I think it would yaw left a bit without it but that could also be fixed with some rudder trim.
The rudder I just sort of faked by adding a 14mm strip to the top of my rudder. Now when I go full rudder I can see the back of the plane kick out so it is working good. I even tried to do some knife edge, but 1) I can't 2) not quite the model for knife edges. It does better than a tiny tranier though. Overall I'd say this is a great easy design that costs very little and the build is super easy. All straight lines makes it easy to cut and the low part count means only a few cuts. It's definitely much more aerobatic than a tiny trainer but doesn't go quite as slow, although this feels more maneuverable on its low end.
Don't forget, I also cut ~1.77mm off the right side of the nose then angled the top/bottom to link the sides to give it ~2 degrees of right thrust. I think it would yaw left a bit without it but that could also be fixed with some rudder trim.
Mad_Mechanic
Well-known member
When my dad and I flew control line many years ago we had a saying:
"Maintain thine airspeed velocity, lest the earth rise up and smite thee."
That being said, I've been re-watching your 2nd maiden video and I still love how you nosed the plane in and then you just picked it up, straightened the prop and sent it back up. That's some decent crash resilience.
BATTLEAXE
Legendary member
I like where this is going, I just finished the airframe sans electronics myself and it did go together quick and easy. All straight lines and not the complications of the TT to mess with any alignment, and as CapnBry has proven it is resilient as well. I did make some changes to it just on the building aspect cuz that's what i do. Tell me what you think:
On the wing I found that you used a sandwich C fold style spar which is something that I quickly folded on my TT, given the TT has a longer wingspan thus increasing leverage on the split in the dihedral. So I made up a box spar to utilize the on edge strength of the FB, it will also help with running servo wires into the fuse instead of opening up the space that the spar indexes into the fuse to make room for the wires, and wont take up any more space on the one sheet of FB. One thing I was thinking of doing was to cut a few inches off the lower wing panel from the wing tips to create the usual under camber for tip stall, but when i thought of this i had already cut the double bevel in the LE. Could also cut down on weight and make room on the FB sheet for improvements. I did notice that because the spar is short of even half the wing that it will be tough for a beginner to maintain a consistent wing chord profile from root to tip. I noticed this after i completely glued the wing that the tips ended up with a flatter profile then the root.
These pics show how where the wing can index into the fuse flush to the bottom creating better contact throughout the mating surfaces. Capnbry did mention earlier how there could be a paper section to transition the fuse to the LE of the wing. Here is a way of doing it by omitting one thickness of redundant FB and again saving on weight of the piece I cut out. If the box spar is used, it makes a direct pathway in the open area to run wires into the fuse again whether the spar is placed with the opening up or down. I also took a page from nerdnics book of tricks and frenched in some bbq skewers for the rim of the fuse that surrounds the top hatch for strength and wear and tear on replacing batteries and getting to the electronics. If you look closely I extended the skewers all the way to where the firewall glues into the front face for impact protection. All said and done it turned out pretty straight and square, again super easy to build:
The top hatch fits in so snug with the skewers on either side of the door. I used a section of tape for the hatch pull instead of the hole in the original plan for durability, and lastly i cut in the naca duct for airflow down the length of the fuse. I really like this design and I will continue on it later, gonna nail down the one servo for ailerons thing and balance for the F Pack with 850mah 3s
This is what I got so far and I can't wait to fly it, maybe tomorrow. Thx for reading
On the wing I found that you used a sandwich C fold style spar which is something that I quickly folded on my TT, given the TT has a longer wingspan thus increasing leverage on the split in the dihedral. So I made up a box spar to utilize the on edge strength of the FB, it will also help with running servo wires into the fuse instead of opening up the space that the spar indexes into the fuse to make room for the wires, and wont take up any more space on the one sheet of FB. One thing I was thinking of doing was to cut a few inches off the lower wing panel from the wing tips to create the usual under camber for tip stall, but when i thought of this i had already cut the double bevel in the LE. Could also cut down on weight and make room on the FB sheet for improvements. I did notice that because the spar is short of even half the wing that it will be tough for a beginner to maintain a consistent wing chord profile from root to tip. I noticed this after i completely glued the wing that the tips ended up with a flatter profile then the root.
These pics show how where the wing can index into the fuse flush to the bottom creating better contact throughout the mating surfaces. Capnbry did mention earlier how there could be a paper section to transition the fuse to the LE of the wing. Here is a way of doing it by omitting one thickness of redundant FB and again saving on weight of the piece I cut out. If the box spar is used, it makes a direct pathway in the open area to run wires into the fuse again whether the spar is placed with the opening up or down. I also took a page from nerdnics book of tricks and frenched in some bbq skewers for the rim of the fuse that surrounds the top hatch for strength and wear and tear on replacing batteries and getting to the electronics. If you look closely I extended the skewers all the way to where the firewall glues into the front face for impact protection. All said and done it turned out pretty straight and square, again super easy to build:
The top hatch fits in so snug with the skewers on either side of the door. I used a section of tape for the hatch pull instead of the hole in the original plan for durability, and lastly i cut in the naca duct for airflow down the length of the fuse. I really like this design and I will continue on it later, gonna nail down the one servo for ailerons thing and balance for the F Pack with 850mah 3s
This is what I got so far and I can't wait to fly it, maybe tomorrow. Thx for reading
Mad_Mechanic
Well-known member
@BATTLEAXE - I toyed with the idea of cutting out a larger portion of the bottom fuselage to recess the wing as you had done but I was concerned that removing that much material would invite issues with folding and maintaining alignment of the fuselage itself. It would make for a smoother airframe though.
Interesting choice going with a box spar. I did the C-fold spar because I had done those building my FT Explorer and new they were simple.
One way to help new builders get the wing shape correct could be to add additional spacers or spar sections to the wing out beyond the aileron servos, but this adds weight and we would need to find adequate real-estate on the foam board sheet.
Overall though I love how people are already starting to build this design and are playing with modifications. It makes it more of a community design that will hopefully be a very good plane.
That trick with the 'frenched in' BBQ skewers is pretty slick, it would also help add a little nose weight.
Interesting choice going with a box spar. I did the C-fold spar because I had done those building my FT Explorer and new they were simple.
One way to help new builders get the wing shape correct could be to add additional spacers or spar sections to the wing out beyond the aileron servos, but this adds weight and we would need to find adequate real-estate on the foam board sheet.
Overall though I love how people are already starting to build this design and are playing with modifications. It makes it more of a community design that will hopefully be a very good plane.
That trick with the 'frenched in' BBQ skewers is pretty slick, it would also help add a little nose weight.
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BATTLEAXE
Legendary member
Actullay "using the table as your friend" made it super simple to fold up. I have seen smaller sections less then a quarter that size go together just as easy.
And if i get this one servo aileron control to work out as hidden into the fuse as possible just like the baby blender or the bloody wonder the linakages wouldnt hang down off the plane any further then the wing mounted ones would. Saving weight and adding simplicity.
Just playin around with it is fun. Ill fly it and see what happens. Ill video the maiden and post and you can make references from there. Thx for reading tho
Mad_Mechanic
Well-known member
Right now I'm honestly just thrilled that people are liking the design enough to build it and experiment with it in it's current form. It tells me that the base design is solid enough to be messed with.
I appreciate all the feedback, hopefully we can combine many of the suggestions for a Prototype Version 2 release here soon.
I appreciate all the feedback, hopefully we can combine many of the suggestions for a Prototype Version 2 release here soon.
CapnBry
Elite member
Yeah that's looking awesome @BATTLEAXE, I like the bigger cutout so everything sits flush, the skewers, box spars, all great ideas! It's such an elegant simple design that it is easy to customize and try new ideas. If things go horribly wrong, then you're just out of the game for a couple of hours while you build a whole new plane.
I wouldn't worry about extending the spar past the servos. The wing is short enough that it is pretty easy to fold accurately-- and this is coming from someone who always ends up with one wing a slightly different size than the other.
I wouldn't worry about extending the spar past the servos. The wing is short enough that it is pretty easy to fold accurately-- and this is coming from someone who always ends up with one wing a slightly different size than the other.
BATTLEAXE
Legendary member
Im thinking that if there was a few inches off the lower wing panel at the tips it would take bound up stress from the LE fold and let the wing stay in a more consistent shape, be easier to fly at slower speeds for beginners (the people that would really find this plane appealing), and save on weight and FB.
I do really like how adaptable this plane is to other designs as well. Like mayan did to his TT by making a Spitfire version of it. Or how buzzbomb and I made biplanes from the Mini Scout and Speedster. Even yesterday I was looking at it as I was building it and thought of what it would look like with a canopy and landing gear lol. Such a great idea on this one Mad_Mechanic. I have the servos in and now its down to installing the powertrain and she will be up in the air today.
Quick question... where should i be looking for CG, mid spar?
Mad_Mechanic
Well-known member
Approximately mid spar is where I had intended cg in Solid works, but you my need to play a little from there to get desirable flight characteristics.
I'll mess with removing some of the underwing like you suggest in SolidWorks today and post up some revision images for review.
I'll mess with removing some of the underwing like you suggest in SolidWorks today and post up some revision images for review.
BATTLEAXE
Legendary member
Aerodynamically should the CG be where the wing creates the majority of its lift in flight or is it more complicated then that?... and where on the airfoil is that lift majority created? I'm actually wondering cuz i don't know how that works exactly. Most models are mid spar, some with a swept wing will be behind the spar at the root of the wing which all makes sense if my theory is correct, but it feels like i am missing something. Do you have anything to help shed some light on this for me?
Hey you already built your wing right? Did you notice the wing profile root to tip issue as well or did servos in the wing help keep it consistent? If it did stay consistent for you I probably should have extended the spar an inch on either side to make up for the lack of servos... it's a thinker.
Thx for the reply
Mad_Mechanic
Well-known member
Yup my first wing is done, I formed it without the servos installed but noticed no issues with wing form from root to tip. Maybe I just got lucky.
I'm not sure I have the best answer for you on this. There are many resources you can read about online (I've read some of them) and there can be a lot of math involved. When I do at least the rough layout/design work for a plane with a straight (non-swept) wing, I use the general rules of thumb that Josh Bixler has suggested in a couple of Flite Test videos. First, for CG I look to have it approximately 1/4 to 1/3 behind the leading edge. This also tends to be where I try to place my spar.
From there I try to use the 'rule of thumb' where my elevator width is approximately 1/3 of the wingspan and the rudder height is approximately 1/2 the width of the elevator.
I hope this helps.
Mad_Mechanic
Well-known member
Is this what you are thinking? This is with 2-in (~50mm) removed from both sides of the lower wing panels.
*There is no science to the 2-in here at the moment
Weight savings as shown is as follows (calculated via solidworks and does not account for weight of glue)
Version 1 prototype wing design: ~66.5 grams
Version 2 prototype proposal (shown) wing design: ~63.2 grams
Theoretical weight savings: 3.3 grams
That sounds fairly negligible, but when you figure that my plan calls for 4x servos that weigh ~6g a piece, that 3.3 grams is about half a servo in weight. It does all add up.
Mad_Mechanic
Well-known member
@CapnBry @BATTLEAXE - Here is where I'm at on fuselage changes.
For reference, here is the flat pattern for the initial prototype design release.
For prototype version 2 (work in progress) I've changed the wing cutout as per what BATTLEAXE suggested. This was an idea that I had considered during the initial prototype design but abandoned it thinking it would add more cuts and reduce fuselage strength. However, thinking about it again, it does reduce a little weight and once you glue the wing in place, you will gain back any lost fuselage strength.
I also added tabs at the back where the elevator mounts which will correspond with slots to be cut into the elevator. This should also help the fuselage hold it's shape, add some strength and does not add additional weight (the weight added to the fuselage is removed from the elevator, thus net-zero).
Lastly, I went ahead and added some length to the nose section as-per CapnBry's suggestion. I maintained the distance from the tail end of the fuselage to the front of the wing (also as per CapnBry). The amount added is ~5/8-in (~16mm). Here is the v1 compared to v2 so you can see the length difference.
As shown, the fuselage weight (without glue) is as follows:
Version 1 Prototype: 20.7 grams
Version 2 (WIP) Prototype: 20.2 grams
Not much weight savings on it's own (~0.5g), but as I said in the wing modification post, it all adds up.
For reference, here is the flat pattern for the initial prototype design release.
For prototype version 2 (work in progress) I've changed the wing cutout as per what BATTLEAXE suggested. This was an idea that I had considered during the initial prototype design but abandoned it thinking it would add more cuts and reduce fuselage strength. However, thinking about it again, it does reduce a little weight and once you glue the wing in place, you will gain back any lost fuselage strength.
I also added tabs at the back where the elevator mounts which will correspond with slots to be cut into the elevator. This should also help the fuselage hold it's shape, add some strength and does not add additional weight (the weight added to the fuselage is removed from the elevator, thus net-zero).
Lastly, I went ahead and added some length to the nose section as-per CapnBry's suggestion. I maintained the distance from the tail end of the fuselage to the front of the wing (also as per CapnBry). The amount added is ~5/8-in (~16mm). Here is the v1 compared to v2 so you can see the length difference.
As shown, the fuselage weight (without glue) is as follows:
Version 1 Prototype: 20.7 grams
Version 2 (WIP) Prototype: 20.2 grams
Not much weight savings on it's own (~0.5g), but as I said in the wing modification post, it all adds up.
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