BATTLEAXE
Legendary member
If your thinkin just for tryin out this plane, glue BBQ skewers to the length of the control rod to stiffen it up and let her rip bro
1 Sheet Plane
- Thread starter Mad_Mechanic
- Start date
Mad_Mechanic
Well-known member
That's an interesting idea that I've not seen suggested before, I might just have to do that.
bracesport
Legendary member
@Mad_Mechanic - maybe you would benefit from small guides made of the nylon sleeves at intervals to control the wire but not restrict movement - also How did you get on with the spars including dihedral? I was suspicious whether the strength would be there at the dihedral? You could always shape a popsicle stick with an appropriate dihedral to bolster the FB? The attached image is one I made for a bigger wing using CA glue (you would only need two sticks)! 
Mad_Mechanic
Well-known member
Didn't think about smaller sections of the nylon sleeve spaces out. That might work for the tail surfaces but might not for the aileron servos.
The wing spar with included dihedral is only a design concept for version 2 at this time. I'm still building my planes as per version 1 plans for the time being before finalizing and releasing the version 2 files.
I'm hoping to compile the feedback from @BATTLEAXE and @CapnBry for the version 2 prototype design.
The wing spar with included dihedral is only a design concept for version 2 at this time. I'm still building my planes as per version 1 plans for the time being before finalizing and releasing the version 2 files.
I'm hoping to compile the feedback from @BATTLEAXE and @CapnBry for the version 2 prototype design.
Mad_Mechanic
Well-known member
I welcome and appreciate any and all design feedback, I noted battleaxe and capnbry because I know they have already built the plane and flew them.
I encourage anyone who is interested to build the plane and help with testing!
I encourage anyone who is interested to build the plane and help with testing!
bracesport
Legendary member
@Mad_Mechanic - for the ailerons, you can make a standoff from the wing with a section of a popsicle stick and add a small section of the tube on top to guide the wire - I did that on my Versa!
Mad_Mechanic
Well-known member
@Mad_Mechanic - for the ailerons you can make a standoff from the wing with a section of a popsicle stick and add a small section of the tube on top to guide the wire!
I actually tried just that, I'll have to post a picture.
CapnBry
Elite member
I can't believe how many tricks I've picked up in this thread alone. Tubes on standoffs, stiffening a rod with a skewer, those posterboard undercamber reinforcers. I think I've picked up more build tricks in this thread than any other.
Stinks about the weather turning your maiden into a Search and Rescue, @BATTLEAXE, I hope you're able to find it. I don't mind busting up a perfectly good model in a crash but it makes my heart sink a bit when I lose one entirely. The planes may cost only a couple bucks in materials, but all those electronics bits really add up. My Dad just lost a UMX Timber yesterday at his field and had a whole crew of people who saw it go down-- it has just vanished. Hopefully, yours didn't go to the Land of Wind and Ghosts.
Stinks about the weather turning your maiden into a Search and Rescue, @BATTLEAXE, I hope you're able to find it. I don't mind busting up a perfectly good model in a crash but it makes my heart sink a bit when I lose one entirely. The planes may cost only a couple bucks in materials, but all those electronics bits really add up. My Dad just lost a UMX Timber yesterday at his field and had a whole crew of people who saw it go down-- it has just vanished. Hopefully, yours didn't go to the Land of Wind and Ghosts.
BATTLEAXE
Legendary member
I've done this same idea many times with the zip tie trick that Chad had on the FT build vids. Actually I had to use it with the 1 sheet plane and the mini scout for the elevator control rod:@Mad_Mechanic - for the ailerons, you can make a standoff from the wing with a section of a popsicle stick and add a small section of the tube on top to guide the wire - I did that on my Versa!
View attachment 139421 View attachment 139422
The popsicle stick/tubing standoff is a cleaner look for sure. Thx @bracesport for the insight on that one.
Yea I totally agree @CapnBry this thread has been a serious learning experience for me to, I would work on any project with you guys any time. There is a various amount of great experience with the three of us between the design, building and flying that it makes a killer trifecta.
Thanks for the concern about the lost plane to man, I am in the same boat as far as the electronics. I am not exactly a disposable income kinda guy right now so getting those components back are important. That's why i build FB planes though, crash and trash the plane is fine as long as the components survive. which is why I am goin back out today with the Quad and do another aerial search. It's gotta be there. Last time i lost a plane in a field of wheat and i searched for 3 hours by walking in a grid pattern while the Quad was flying over. I didn't find it till the next day and did a 10 minute walk and I found it 20 feet from my furthest point I was the day before. I'll keep you posted. In the meantime @Mad_Mechanic get your plane built and fly it.
Mad_Mechanic
Well-known member
Ok, so here are pictures from my pushrod woes over the last 2 nights.
I'm rather ashamed to even admit that this was my first attempt at tail control pushrods. The elevator doesn't look too terrible per-say, except for that rather extreme slope from the servo to the sleeve. The rudder control is just...well...I don't know what I was thinking other than I had hoped with just how flexible this pushrod stock is it would be ok. It wasn't. The servos here did not like this at all and would bind up and whine.
I attempted to fix this by adding foamboard standoffs for the sleeves:
This helped a lot, but I still have some issues with buckling.
Here is the aileron, Initially I was trying to not use the sleeve. When I built my FT explorer sport wing and used the FT speed build kit provided pushrod stock it was larger diameter and stiff enough that I could run it from the aileron servos to the control surface without a guide sleeve, I had hoped I could do the same here with this pushrod stock but again it's just too thin and too prone to buckling. So I tried to use a section of sleeve and a standoff made from foamboard.
The issue here is that now the system is too stiff and the servo binds up and whines.
I'm actually considering completely re-orienting the servo within the wing and laying it on it's side instead of poking out like I currently have it mounted. It means a bit of wing surgery but hey, this is prototype stage and now is the time to figure this stuff out.
The reason I had envisioned mounting the aileron servos like this in the first place is because this is how they are done in the FT Explorer sport wing and it makes the hole in the wing very simple.
Laying the aileron servo flat on it's side for mounting means taking 1 of 2 possible design routes. If we keep the full underwing (no undercamber) then we have to have a larger cutout in the underside of the wing to accommodate a servo laid flat. However, if one builds a wing with an aggressive undercamber cut the servo can be mounted flat and nested inside the wing with the control horn screw easily accessible.
I'll mock up what I'm trying to say in SolidWorks later today to better explain.
I'm rather ashamed to even admit that this was my first attempt at tail control pushrods. The elevator doesn't look too terrible per-say, except for that rather extreme slope from the servo to the sleeve. The rudder control is just...well...I don't know what I was thinking other than I had hoped with just how flexible this pushrod stock is it would be ok. It wasn't. The servos here did not like this at all and would bind up and whine.
I attempted to fix this by adding foamboard standoffs for the sleeves:
This helped a lot, but I still have some issues with buckling.
Here is the aileron, Initially I was trying to not use the sleeve. When I built my FT explorer sport wing and used the FT speed build kit provided pushrod stock it was larger diameter and stiff enough that I could run it from the aileron servos to the control surface without a guide sleeve, I had hoped I could do the same here with this pushrod stock but again it's just too thin and too prone to buckling. So I tried to use a section of sleeve and a standoff made from foamboard.
The issue here is that now the system is too stiff and the servo binds up and whines.
I'm actually considering completely re-orienting the servo within the wing and laying it on it's side instead of poking out like I currently have it mounted. It means a bit of wing surgery but hey, this is prototype stage and now is the time to figure this stuff out.
The reason I had envisioned mounting the aileron servos like this in the first place is because this is how they are done in the FT Explorer sport wing and it makes the hole in the wing very simple.
Laying the aileron servo flat on it's side for mounting means taking 1 of 2 possible design routes. If we keep the full underwing (no undercamber) then we have to have a larger cutout in the underside of the wing to accommodate a servo laid flat. However, if one builds a wing with an aggressive undercamber cut the servo can be mounted flat and nested inside the wing with the control horn screw easily accessible.
I'll mock up what I'm trying to say in SolidWorks later today to better explain.
BATTLEAXE
Legendary member
I like how you think @Mad_Mechanic. You seem to be a strong designer in CAD and in need of some tutelage on the build side. It's entertaining and kinda cute actually, I got ya bro. Check this out:
These are pics of my Spitfire build, (flew it the other night, what a sweet experience with my first warbird), anyway, and how there are a couple of principles you need to follow for a consistent control surface actuation. 1/ The servo in relation to the control horn should be as linear as possible meaning, the pivot point on the servo should try to match the pivot point on the control surface. This point, if you keep it in mind the whole way in designing this stuff, should keep you safe on many levels. In the first pic you can see how the control rod is a straight shot from the servo to the control rod in relation to where the control rod connects to each component on both ends. This is because the distance between the screw hole in the servo to the hole on the servo control horn is the same as the distance from the hinge point of the control surface to the hole in the control horn, (wow it's harder to explain by typing then by showing someone in person or by video). you will see the same point in the second pic except the servo is flipped 180 degrees to actuate from the opposite side of the pivot point... make sense? 2/ Mounting your control horn so the hole lines up directly over the hinge point of the control surface eliminates pretty much all the binding because just like in the first point the actuation becomes mechanically linear, the slave side of the control rod moves exactly like the master side. I bet that most of the flex in your pushrods is due to the offset of the control horns in relation to the servo horns, even if your pushrod stock is flexy to begin with. You could've still used the same pushrod stock and glued bbq skewers running the length of the pushrod to stiffen it up, as long as your linear geometry is right and efficiently actuates with the least amount of binding you will be good to go.
Now as far as the placement of your aileron servos i totally agree with the change of laying them flat. I was actually going to mention it the other day but I didn't want to dominate your design with a crap ton of my own improvisions, (is that even a word, I don't think so, spell check says "no" lol). With or without the under camber this works so well. not only would a 5g servo fit with a 3/8" thick spar, (or double thick), but 9g servos work with minimal effort and they get installed in the wing before you fold it over and close it off. you can see how much cleaner the placement of the servo is within the under camber of the wing is in the first pic, but check this out. These next pics are from my Shrubsmacker that Grifflyer designed and I built, I love flying this plane too, but take a look:
This is what the full "no under camber" install would look like. Cut slit in the wing is just for the servo arm and not the whole ugly servo. Now this technique is a bit more complicated then just your basic build techniques but it sure looks sharp. All it takes is to score cut the servo shape in the inside of the wing lower panel and empty the cavity of foam so the servo completely indexes inside the cuts, then completely cut through for the servo arm so it extends past the paper and works the control rod. Its easy to do once you understand it and i think it's a clean efficient design
Here is a better example of the servo placement for the elevator on the Shrubsmacker. Illustrates better geometry. Does this help at all? Let me know what you think
Mad_Mechanic
Well-known member
I appreciate your tact in trying to "not dominate the design process". It's true that I have very well developed CAD skills (almost 10 years with SolidWorks and about 5 years with AutoCAD prior to that), but my actual build experience is...lacking in some respects.
Intuitively I knew that laying the aileron servos flat would be better functionally. Just visualizing how the two connection points for the pushrod have to pivot. Anyway, I was hoping the version 1 aileron servo orientation would work alright because it's how it's done on the FT Explorer sport wing. Live and learn I guess.
The hesitation I have with completely burying the aileron servo in the wing before folding comes down to servicing/adjusting the servo later. This stems from my desire as an mechanical engineer (my day job), I like to design things with serviceability in mind.
Perhaps this is a compromise that has to be made, recognizing how cheap this airframe is perhaps it's not worth worrying about.
Something else I've thought about is moving the tail surface servos back on the fuselage. This would shorten the pushrod runs, however I would have to see how the overall CG changes when doing that. Thankfully that's where SolidWorks comes in VERY handy as I can experiment with changes and see how they affect the theoretical CG.
I have an idea on the tail surfaces too that I'm going to mess with over my lunch and post up fresh concepts to see what people think.
The one thing I want to be careful of at this point is that I don't want to mess up an already good thing. From CapnBry's feedback, the plane flies really well as per the version 1 design, so I don't want to make changes that are a detriment.
Intuitively I knew that laying the aileron servos flat would be better functionally. Just visualizing how the two connection points for the pushrod have to pivot. Anyway, I was hoping the version 1 aileron servo orientation would work alright because it's how it's done on the FT Explorer sport wing. Live and learn I guess.
The hesitation I have with completely burying the aileron servo in the wing before folding comes down to servicing/adjusting the servo later. This stems from my desire as an mechanical engineer (my day job), I like to design things with serviceability in mind.
Perhaps this is a compromise that has to be made, recognizing how cheap this airframe is perhaps it's not worth worrying about.
Something else I've thought about is moving the tail surface servos back on the fuselage. This would shorten the pushrod runs, however I would have to see how the overall CG changes when doing that. Thankfully that's where SolidWorks comes in VERY handy as I can experiment with changes and see how they affect the theoretical CG.
I have an idea on the tail surfaces too that I'm going to mess with over my lunch and post up fresh concepts to see what people think.
The one thing I want to be careful of at this point is that I don't want to mess up an already good thing. From CapnBry's feedback, the plane flies really well as per the version 1 design, so I don't want to make changes that are a detriment.
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BATTLEAXE
Legendary member
Just like anything else that has been designed in any sense of the word there is always a version 1, and granted @CapnBry is a better pilot by far then the both of us probably put together, there is always room for improvements not only on the flying side but on the ease of build side as well. Its a simple plane that need to be simple to build, and if it's complicated to build no beginner will want to build it. Vicious circle lol. Point being is there is always room for improvement. And to be candid for example sake, Would you rather fly the plane that @CapnBry built or the plane you have spent the past 2 nights on?... Not to be an a#$hole here but you do have to appreciate that everyone will take your base plan and make it their own in some way or another not only to improve as pilots but to enhance building skills as well. And each individual plane will fly different, even 2 planes built by the same person to some degree or another. It's a great design and I think it has a lot of potential as it sits in version 1, and the great thing is that you have a full forum of people to help make improvements to take a good thing and make it great.
My self i suck at any CAD operations, beyond typing this message i am pretty much computer illiterate lol. I'm more of a pencil to paper kinda guy. So i am so grateful their are people such as yourself to offer those kinda skills that push any project into fruition. And then there is @CapnBry who has the hand/eye coordination and muscle memory to take any design and fly it and give you respectable feedback as a seasoned pilot. Killer trifecta my friend. Keep pluggin away and take her up. See what happens and report back bro
Mad_Mechanic
Well-known member
No offense taken! So far I love how two people have taken the version 1 design and attacked the single-servo aileron idea from two different approaches. What that showed me is that I managed to design something from the start that is simple and highly adaptable.
That's a 'feature' I would very much like to retain moving forward. I think the vision here is to release a set of plans that are simple to build for a novice but provides a base design that anyone can experiment with. That being said, I want the base design to be stable enough for a novice pilot to not be scared to fly. To that end, if we can improve the plans low-speed flight characteristics, I think that's a good design goal to have.
I'm nearly done with my tail surface concept and I'll have screenshots up shortly for review and feedback, I have no idea if this is a good idea (I don't think it's a bad one).
Mad_Mechanic
Well-known member
Alright! Here we go!
@CapnBry @BATTLEAXE - here is a round of brainstorming I messed with over my lunch break.
Here is a list of proposed changes in this concept. Again this is just concept proposals and nothing has been officially changed on the design yet.
Perhaps the biggest change you might notice is that I moved the elevator down on the fuselage. This could be a problematic or controversial change but I saw some benefits in doing this. For one, it buys just a little bit more rudder control surface.
I also moved the tail control servos back on the fuselage, thankfully it looks like this didn't affect the nominal CG point too badly. the goal here is to allow for shorter pushrod lengths.
The next change is the wing with mounting the aileron servos flat and cutting for undercamber. I recognize this is a bit of a debated design move by having undercamber so this might still go back and forth a bit. I also increased the length of the ailerons a little, about 1-in (~25mm) on each side.
Obviously, one could still make the aileron full wing length easily if they so desire but for now I'm hesitant to do this on the base design.
Ok, so there are my proposals for today. I open this up to the forum to chime in and critique.
@CapnBry @BATTLEAXE - here is a round of brainstorming I messed with over my lunch break.
Here is a list of proposed changes in this concept. Again this is just concept proposals and nothing has been officially changed on the design yet.
Perhaps the biggest change you might notice is that I moved the elevator down on the fuselage. This could be a problematic or controversial change but I saw some benefits in doing this. For one, it buys just a little bit more rudder control surface.
I also moved the tail control servos back on the fuselage, thankfully it looks like this didn't affect the nominal CG point too badly. the goal here is to allow for shorter pushrod lengths.
The next change is the wing with mounting the aileron servos flat and cutting for undercamber. I recognize this is a bit of a debated design move by having undercamber so this might still go back and forth a bit. I also increased the length of the ailerons a little, about 1-in (~25mm) on each side.
Obviously, one could still make the aileron full wing length easily if they so desire but for now I'm hesitant to do this on the base design.
Ok, so there are my proposals for today. I open this up to the forum to chime in and critique.
bracesport
Legendary member
@Mad_Mechanic - my two cents...
If you look at @BATTLEAXE 's pushrod images and possibly my Versa images, what's common is that you need some space from a guide to both the servo arm and the control arm. This is to allow movement of the rod without binding with the guides (given both the servo arm and the control arms move in a curve, which in turn, slightly changes the path of the rod).
My preference is for 0.8mm wire, but that's just me.
FYI - I think @BATTLEAXE 's pictures are a great reference for any build!
If you look at @BATTLEAXE 's pushrod images and possibly my Versa images, what's common is that you need some space from a guide to both the servo arm and the control arm. This is to allow movement of the rod without binding with the guides (given both the servo arm and the control arms move in a curve, which in turn, slightly changes the path of the rod).
My preference is for 0.8mm wire, but that's just me.
FYI - I think @BATTLEAXE 's pictures are a great reference for any build!
Mad_Mechanic
Well-known member
Just another quick thought, why not mount the aileron servos in the fuselage like this?
This would mean you eliminate any possible need for servo lead extensions for the aileron servos. However, it could interfere with options for where to place the battery for balance.
This would mean you eliminate any possible need for servo lead extensions for the aileron servos. However, it could interfere with options for where to place the battery for balance.
bracesport
Legendary member
@Mad_Mechanic - no reason why not - I have the aileron servos in the fuse for my DLG and that has a 1.5m wing with full-span ailerons!
Mad_Mechanic
Well-known member
@Mad_Mechanic - no reason why not - I have the aileron servos in the fuse for my DLG and that has a 1.5m wing with full-span ailerons!
This is a perfect example of how I start on a design project with one mental image or vision and then don't fully explore other options.
Engineer's tunnel vision 😅
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