|Nov 19, 2012, 03:46 AM|
MIBO Terminator Build
New to the forum. Going to put together a new MiBo Terminator that I ordered from David/Esprit. WIll post my build as I have many questions as I start to put it together set everything up. Only got everything spread out now, bits and pieces on order, waiting for my Hacker B40 10S and focusing on getting servos, wiring and control linkages installed.
I got back in the RC hobby a year ago or so. I have a little bit of experience in the hobby, so I'm not a complete newbie. Trying to learn how to fly a TREX 700e now (not sure if I've got the stuff for the helis), got a eFlite Carbon Z, a 3DHS 38 Slick Foamie. As a kid, I flew .40 size planes and "gliders" back in the mid 70's in Spain. Dad was a Wing Commander In Zaragoza. Dad said it was too expensive a hobby until a couple of Master Sergeants told my Dad that I'd be cooped up in my model room on weekends instead of hanging out with other kids smoking hash. They were right and o'l Dad quickly changed his mind.
Sorta got back in the hobby back in the early 90's with some sailplanes. Flew an Airtronics Legend then.
Have always loved the look and grace of a sailplane flying. Want to eventually move into large scale sailplanes too.
So, I spent the day today making up some HS-5125 mounts for my wings. Didn't want to glue the servos in, without being able to get them out. Read where some people shrink wrap and glue them in. I figured that this SP could have huge control surfaces loads (maybe not, deflection may be minimal for flight maneuvers) or a hard landing will pop the servos loose. Pics below.
Here are my first questions about ail/flap control horns, and servo arm positions:
1. I've seen photos of another MIBO T on this site (Phil Davy) with the control horns mounted on top of the flaps and ailerons with the linkages coming up from inside the bottom of the wing out near the top trailing edge to the horns. Photos of the MIBO T on Esprit's web site has the horns mounted on the bottom. Can anyone give me any insight as to what is the best way to rig up the aileron and flap horns/linkages. Why top vs. bottom?
2. I believe the ail. horns are inline with the hinge line. Flap horns are supposed to be offset. Forward or in back of the hinge line? How far to offset?
3. What angle/position of the servo arms supposed to be in with the ail at neutral stick? Same goes for the arm for the flap servos, I guess when the throttle stick is all the way forward?
4. The control horns are thin fiberglass. These seem really weak. Lots of slop when linkages connected. Should I replace them, With want? I looked at some 3-4 mm brass pin aftermarket things.
Thanks. Will enjoy talking with everyone.Attachment 5313881
|Dec 30, 2012, 05:06 AM|
Mibo Terminator build continues
Been pretty busy over the holidays with the Terminator build and other related projects. Mostly been used to bind-&-flys and quick ARF builds. After some heavy reading on the many different types of RC sailplanes and their builds, I thought, whoa, gotta seriously plan this out in much more detail and get everything working both mechanically and electrically before I start glueing and installing.
Continue to concentrate on the flaps/aileron mechanics and electrical. I may need to redo my control links and use one diameter smaller carbon rods. My wings are really thin and the HiTec HS5125MG's are just barely going to fit. Needed to cut down my servo arms and drill a new hole in each one to get them to fit under the included hatch covers.
|Dec 30, 2012, 06:00 AM|
Wing Servo Bay Covers
Well, in this trial fitting everything before I glue a thing together, I just found out one of my aileron servo bay covers is the wrong size. The wings are so thin outboard with the aileron servos that there is a distinctly larger "Bubble" cover to mount over the aileron servos/linkage arms (you can see the difference of the 4 hatch covers sitting on top of the foam in the picture below). There is no way I'm going to get the "extra" flap cover to work over the aileron bay.
I think Mibo is a Czech kit. No way I'm going to be able to get someone on the phone to send a new one. I'm very happy with the fit and finish of the kit. First class sailplane. But what to do?
Smaller servos? No. Fiberglass molds? Too difficult of a process to master? Couldn't find some off-the-shelf ones that would work. My covers have a raised "peak" in the back towards the wing trailing edge where the rear of the servos stick up a bit above the top surface of the wings.
While trying to source new ones, I stumbled onto people making a simple vacuum forming box. So I made one. Figured it would come in handy making some small covers for my top drive linkages too.
Got it all together, but have been waiting for some thin lexan that I ordered online to try it out. Was out picking up groceries for Christmas morning brunch and walked by the paper plate and cups section. Saw some PINK!!!! plastic plates that are obviously commercially vacuum formed. Don't know what kind of plastic it is but, I figured if it was vacuum formed I could use some as a test to vacuum form again.
It works great! I may sand down my molds a little bit more for a smaller profile. ABS and styrine comes in black to match my flap covers (which are really fiberglass layups). Lexan only comes in clear. I may see what clear covers look like. I kind of like the idea of being able to see inside the servo bays from time to time to check for any potential mishaps.
|Dec 31, 2012, 01:44 AM|
Outstanding workmanship and kudos for taking your time on the build.
Love the vac former.
As for flap horns; angle them towards the servo 15 degrees from vertical or thereabouts.
As the flap deflects down to 60-70-80 degrees you need the clevis to clear the lower skin and angling them forwards would give you that.
If the flaps are bottom hinged, top-drive them; there's better mechanical advantage that way.
My Sunbird build recently might help:
Aileron servo arm set to vertical. Flap servo arm angled away from the flap; again 15 degrees should do it. It's done for mechanical advantage
at large deflections; the flaps go a up a little for reflex and also when mixed with ailerons but go down a long way for braking.
As for throttle stick aka flap stick I fly with mine all the way forward and only pull it back for landing / braking.
Replace horns with PCB with the copper sanded off.
There's a Mibo Terminator review in Aufwind and the verdict is it's a rocket !
Looking forward to your road test of this ship,
|Dec 31, 2012, 06:22 AM|
Flap + Aileron Horns
Thanks for the advice. I had already made the decision to use these brass pins for the aileron and flap horns instead of PCB/carbon horns. Thought they would be stronger. Little did I know how hard it was going to be trying to figure out how to mount them since Mibo didn't include these in the moulding of their wings.
When I finally got the nerve to cut into the beautiful wings to figure out how to mount the pins, I found out what I've read about hollow core wings. They really are hollow. Not much to mount to. So after days of trying different bases to mount the pins into the wings I've settled on the aluminum horns that I made up in the following photos.
I finally got the flap horns working perfectly, the horn holes are directly over the hinge line (or slightly forward), angled forward about 15 deg, etc. My control link rods are straight with no bends needed and no binding or rubbing. I still need to tape the servos in the wings and mock/hook up a battery/RX and double check how they work mechanically before I glue them in.
However, in reading you comments about the aileron horns, you said to mount the horns vertically. I've seen pictures of pins mounted straight up, but that seems really weak and the pics of these horns seem to be behind the hinge lines. I've also seen pictures of the ail. horns mounted at an angle like the flaps, low profile, almost buried into the trailing edge of the wings.
In the pictures below, I made up another set of horns just like my flap horns. The pin arms are tilted forward about the same 15 deg, etc. This is the only way I could figure out how to get the horn holes over the hinge line. I made these horns long/to cut deep into the flaps and ail so they would sort of act like a lever and spread out the mechanical forces a little bit rather than the pins sticking straight down into my control surfaces like a gear shift in a car.
I was planning on working all day on the Ail. horns today. Will the horns work the way I have them set up?
I'm also worried about servo/mechanical resolution with these sailplanes. I'm used to big 3D electric planes from 3DHS - connect the linkage further out on the servo arms and connect the control rod to the control surface horns inner hole for big throws.
These sailplane wings are different - you must use the inner most hole on the servo arm to fit in the wings and the control link attaches to the "inner hole" of the control surface horn to get them down close to the wings to avoid drag, and problems of binding of the rods going from the bottom of the wing to the top drive. This seems screwy to me and I can't get my head around it until I can get things hooked up and working to see what happens.
|Dec 31, 2012, 09:30 AM|
You are doing a great job and are much neater than my own less tidy workmanship .
However I thought a picture of the aileron install on my Surprise 16 (2 metre 5kW powered glider) might give you confidence that your set up won't fail on load.
The surface horn is just 1.5mm glass/epoxy board epoxied into a slot in the hollow ailerons - no problems yet in a couple of years use at speeds up to 150 mph..
The picture shows the bottom of the wing and the ailerons are top hinged. Note that the servo horn is angled about 15 degrees away from the control surface, as I need the ailerons to go up about 45 degrees as spoilers for landing.
The flap install is similar but the flaps come down for landing so the horn is angled towards the surface.
The servo is a 9mm thick Hyperion DS09 which is about the thickest that will fit in the wing at that point, and even that needs a slight bulge in the wing.
You are doing OK - take your time and you will soon get your head around the control linkage geometry
|Jan 04, 2013, 09:44 PM|
Good Lord! I'm still messing with the flaps for the last 3 weeks!
Thanks Dick. I've gone through the Surprise 16 thread and have picked up a number of comments/pics that have been a big help.
I'm pulling my hair out. I'm still been messing with my flaps for the last 3 weeks, trying to make sure they are right and at the same time, thinking about the ailerons since the install/setup is just about similar, except the ailerons don't have to move any more than 8-10mm both up and down. Making progress, but more questions have popped up.
I've got one flap horn, flap servo tray installed. I hope I didn't screw up and position my flap horn to low. The bottom of the hole in the flap horn is level with the top surface of the flap control surface skin. SoI hat makes the center of the hole about 1/32 above the skin surface. In taping together/temporarily mounting the servo, control link and horn, I found this was the best position for the flap horn hole to give me a straight control link and 70-80% of down flap. Positioning the flap horn hole slightly higher dramatically dropped off the flaps from being able to drop 70%.
Now, I've been thinking about the aileron horn install. Trying to figure out if I need to make the position of the hole in the horn a little higher above the control surface skin so I can get more total servo throw for better resolution and get as much mechanical advantage/servo power as possible. My head is spinning reading forums about link geometry, servo throws, servo steps, resolution and mechanical advantage.
So here are some more photos of the progress. Hopefully, all this will help future newbies learn some of my build techniques get through their first 6 servo full house sailplane set up.
|Jan 05, 2013, 01:14 AM|
Servo + Control Surface Mock-Up
Still haven't gotten my head around all of the servo resolution, geometry and mechanical advantage stuff. SO I made up this little mock up of a servo and control surface thing to see what happens when I change the position of the rod in different holes in both the servo and horn and the geometry of the control rod.
This mock up has been set up to be real close to the mechanics of my Mibo wing. Servo horn distance and angles of the servo horn/control linkage to the horn are as close as I could get it to match.
I've also shot a little video of this working which i'll try to see how to upload in a few. I think I've got my mechanicals set up right for the flap until it drops down to about 65-80%. Everything is real tight and no slop. But when the flap drops to 70% to brake for landing, the flap can be pushed back about a .25" or so by wind pressure and is loosey-goosey-sloppy.
Can anyone tell me how to fix this for the flap?
This little mock up tells me my ailerons will be mechanically right – tight and no slop. But raises the question that I'll only need to move my TX stick a 1/4" to get the recommended full throws of 8-10mm - i.e., the servo arm only has to move a little bit. I've been reading about how you want your servos to move through as much as full throws as possible to get the best resolution. And you don't want to turn your D/R on to far or adjust your ATV/servo end points to compensate. All this should be adjusted mechanically as much as possible. All of the TX functions are to be used for fine tuning only???
Am I correct in this assessment? How do you do this with a top drive sailplane aileron? With the control link connected to the inner most hole, you don't want a control horn that is .75" to 1.25" long sticking up on top of the wing? (I actually drilled a new, closer hole to the center spline of my servo horns to get them to fit in my servo wing bays).
|Jan 06, 2013, 08:30 PM|
Like the mock-up.
Speaking generally, flap servo geometry is not a perfect system by a long shot.
Assuming you haven't seen this from Mike Evans, it could help:
There's a goldmine of helpful info there although it doesn't show exactly where the flap horns sit relative to the hinge line.
I could also suggest Tom Copp's helpful article on this:
See image below from Tom's site; the bottom-most example A1.2.
That's a good indication of where the horn needs to be relative to the hinge line...assuming the hinge line is slightly in front
of the flap subspar. Ultimately the clevis hole needs to be in front of the hinge line. As the servo rotates for down flap
the flap horn trends to vertical and not past vertical.
|Jan 07, 2013, 02:09 AM|
Man-o-man Dr. Frag, wish I had both of the above articles to go by as I was trying to figure everything out. Good stuff. I've read dozens and dozens of similar articles in many forums. Tom's article would have been particularly helpful in the beginning.
Well, I went ahead and installed all of my horns for both the ailerons and flaps. They're epoxied in now. I couldn't figure out how to eliminate the little bit of slop in the flaps when they are dropped down to about 70 deg. My flap horn clevis holes are slightly forward of the hinge line (about 1/2mm). Now that I've read Tom's article, maybe I should have moved the horn clevis holes forward about another 2-4mm. Maybe that would have tightened up my flaps when dropped all the way. I'll have to test it out on my little servo/control surface test stand. It doesn't seem like it would make much of a difference though. I can see visually on my test stand that it is and control arm angle/geometry problem.
Both the aileron's and flaps are rock solid up or down about 35mm. Basically only need ±10mm on the ailerons. Less for the flaps until it's time to come in to land. I sat back and kind of thought how I'm going to fly the Mibo Terminator. I live in Texas. No mountains or much in the way of any hills for that matter anywhere near here. SO I won;t be doing any slope flying (there is a landfill manmade mountain area that I've heard about that some people have been flying at. I'll be flying at my local AMA field, doing high speed passes, vertical climbs, aerobatics, etc. and may look into some of the F5 task timed events.
My big worry is how fast this thing is going to go, if I'm going to be able to handle it and how am I going to get it down to land. I was kind of going to add some camber to slow here down, run the motor at 1/2 to 3/4 speed on my first flights to get everything trimmed out/cg set up etc. And work up from there for speed. When landing, I kind of thought I'm not going to really need a lot of massive flap to stop her in mid air. I just want to get her slowed down enough to maintain controlable flight a land as gently as I can so not to tear it up when she slides across the grass.
Sometimes I think I should have chosen a different sailplane, something a lot bigger (3-4m) with a lot less wing loading so It can thermal a little better. I've been using reader glasses for the last 4-5 years. My distance vision has gone to hell and I just got my first pair of fancy blended bifocals prescription glasses and there is no way I'm going to be able to use them for anything or get used to them. I gotta call and find out if you can just get a pair of glasses to correct for my distance vision only as I get older. This vision thing sucks.
Here are some more pics of the build.
|Jan 07, 2013, 02:18 AM|
Dr. Frag,, I'm usually pretty good with my Geography, but I had to stop and think what county Tasmania was in.... thought it was near Australia. I was close, had to look it up.
Always wanted to visit down under. It's on my bucket list.
|Jan 07, 2013, 02:29 AM|
Tricked out Spektrum DX18
On another note, I have been learning how to use a small CNC milling machine.
Been tricking out my new Spektrum DX18 TX. Also been having a hard time learning how to fly my Trex 700e V2. ALways feel uncomfortable holding my TX and noticed a lot of Europeans use TX trays. So I designed and milled my own. Note quite done with it yet. Still need to design and mill a stand and finish anodizing some of the parts to protect the raw aluminum.
I was surprised how solid the TX feels when mounted in the tray. This may be a winner. Although, I'm beginning to think it's my distance vision going out that is causing me having a hard time to learn how to fly my hell. I'm not able to see the subtle attitude shifts and movements and seem to be always behind correcting.
Just made a mental note to search the forums to see if there are some threads that talk about what other people are doing for glasses in the RC Hobby.
|Jan 07, 2013, 03:54 AM|
Impressive work; love the recessed lip around the red wrist rests (say that fast!).
It gives it a more unified look.
As for having reservations about this ship you might be right. It'll be quick and it's small so will test your eyesight.
The Nan Models Orion is 2.4m and might be an even better fit. I've never flown one but heard good reports. It's on my list.
I can also heartily recommend the Xperience Pro. I had the thermal x-tail version and it's still my favourite glider despite owning / flying quite a few now. Slippery section and insane roll rate thanks to light tips. Only 3.32m / 131" though so loses out to the bigger ships on area only.
Tweaking your elevator compensation for landing flap is pretty important however and that's something that takes a few goes to get right. All of them in the air ;0)
As for flap "blow-back" or " loosey-goosey-sloppy" on landing if you can get even 45 deg flap it'll slow it down a lot. Just maintain your angle of attack constant (using elevator compensation) and a tad of up aileron to keep them "flying" and reduce chances of tip-stall.
|Jan 10, 2013, 11:59 PM|
Red Wrist Rest
Red wrist rest, red wrist rist, red rid rid, red wrist rid....haha.
Chris, I'm in the process of maybe buying some land, designing my retirement home which will be about 45 minutes west of here on a lake. My local flying field 10 minutes from where I live now is going to be too small to fly the Mibo Terminator at. Solid tree lines on 3 sides and no fly zone behind.
There is another AMA club that will be 10 minutes near my new home that has wide open spaces for as far as the eye can see. I was planning on visiting this club to maiden the Terminator, get used to how it flys, etc. before I attempt to fly at my local field.
I may shelve the terminator for a year and I've been looking at the some of the larger Nan Xplorers. I think the Xplorers are geared specifically for F3J competition, extreme light/fragile ships that are good for a year if flying competitivly before you'd want a newer/newest thing, maximized thermal duration, maybe some of the task events I guess. I'd have to go back and look again if any of the Exploers are also designed and available electrics/F5 stuff. I looked at all of your posts/pictures you have posted. You obviously have been a serious flyer for a long time and know quite a bit about whats what.
I may call Soaring USA tomorrow to talk to them about the Xperience Pro to build/fly to get me used to all of the programming/setting everything up and then transition back to the Terminator when I have more time under my belt. Plus, I know I would be comfortable slowing this one down to land at my current flying field. I think the XP may be quite a bit more zippy that the larger Xploeres, well rounded glider for high speed runs, good thermeling, aerobatics, etc.
What motor would you use or have used in yours? If I wanted a motor for extreme vertical climbs, what motor would you upgrade to? Same goes for the ESC. I'm used to e-flte and Phoenix/ICE ESCs in my other models. Don't know much about any foreign brands like Jett, etc.
What size of lipos to use? Pair two 3s or 4s together or one single 6s or what. I seem to have every damn size of lipo in pairs for each of my models and helis and non have ever been able to be used in another ship.
What servos would you recommend for the Rud/Elevator ... Ailerons and flaps. I've since read all kinds of reviews about Hitecs 5125mg, Hyperions, Futabas, etc. and my head is clouded on what is the best reliable, return to center servos, etc.
|Jan 11, 2013, 12:49 AM|
Xplorer is a wise choice
The house on the lake sounds like a great project.
Xplorers are more popular than the Xpro meaning there are spares readily available if you need them. Xplorer has better hang time (L/D)
The new Xplorer 2 has a more slippery wing and lighter layups (spread-tow fabrics). It's on my wish list.
My 2010 X3.5 full-carbon is a delight to fly. Roll rate not as agile as the Xpro but more than makes up for it with outstanding thermal performance.
I've only ever flown winched / slope gliders so you might have to ask someone else regarding electrickery.
As a pure glider they're amazing and as an electric I expect just as good. Bob at SUSA will sort you out.
As for servos, my Xplorer runs JR3421 elevator and flaps, JR 362 (368bb) rudder and ailerons.
It's a pretty flawless combo. and they all fit under the servo cover without an unsightly bulge.
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