waltr
Well-Known Member
Is there any incidence between the canard and main wing?
Maybe make fuselage longer, sticking behind wing so less weight needed.
Maybe make fuselage longer, sticking behind wing so less weight needed.
Edmonds Aerospace CiCi build
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Canard wing is preset at negative 3° relative to the main wing. I didn't want to mess with increasing the canard angle and risk it looping into the ground. That said, I've cranked up the angle with BG canards and get around the looping problems by adjusting the booster pod length and/or weighting the nose cone so that the launch CG falls right over the canard wing.
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Had an ideal flying opportunity today – clear skies, winds 5mph, 53°F – and took it. Despite the Cici’s relatively hefty size/weight ratio, it put in a decent flight on a B4-2, with no unexpected surprises. Due to the amount of counterweighting necessary on the aft end, its altitude and flight duration were, as expected, low and short, its flight fairly docile if not a bit wobbly after transition.
Because it exhibited a bit of initial stalling, I think removing a small amount of tail weight might prove beneficial. It finally settled into a smooth gliding decent right back to the pad.
I like that it’s an easy-to-build, great small-field flyer that’s not likely to get lost on some errant thermal…unless you send it aloft on a C6-3; in which case you do stand a chance of losing it to a hungry tree.
On a stroke of good luck (and due to @TigerHawk 's kind heads-up about someone on YORF selling some Edmonds Aerospace models), I was able to get an original unopened Cici kit. It’ll be interesting to see if the kit Cici has the same nose-heavy condition. Or if not, why not?
Because it exhibited a bit of initial stalling, I think removing a small amount of tail weight might prove beneficial. It finally settled into a smooth gliding decent right back to the pad.
I like that it’s an easy-to-build, great small-field flyer that’s not likely to get lost on some errant thermal…unless you send it aloft on a C6-3; in which case you do stand a chance of losing it to a hungry tree.
On a stroke of good luck (and due to @TigerHawk 's kind heads-up about someone on YORF selling some Edmonds Aerospace models), I was able to get an original unopened Cici kit. It’ll be interesting to see if the kit Cici has the same nose-heavy condition. Or if not, why not?
...to be continued
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waltr
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Ok on 3° incidence, sounds about right. Couldn't see if there was any from the photos.
Good to hear it flew well.
Good to hear it flew well.
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Package unsealed, this should go together pretty quickly.
Squashed motor tube was the only casualty so far. No problem, just replaced it with another from my stash.
Squashed motor tube was the only casualty so far. No problem, just replaced it with another from my stash.
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Again, 2 vent holes are punched 180° apart to minimize the fuselage-snapping problem.
Followed my usual practice of punching pinholes in the areas where balsa parts are joined. Helps the wood glue or CA to penetrate better.
Followed my usual practice of punching pinholes in the areas where balsa parts are joined. Helps the wood glue or CA to penetrate better.
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Main wing cemented and filleted to fuselage.
Since I build primarily gliders, one of the “gotchas” I always run into is getting the motor pod glued on straight using only the eyeball app (prone to a finicky accuracy rate). I finally got around to fabricating a ridiculously simple jig that I can use for all my RG builds. Should’ve done it sooner and saved a lot of time and exasperation.
I’ve decided to initially keep things completely “stock” (i.e., no rounding of wing or canard edges, no tissuing, no airfoiling, no doping surfaces etc.) just to see what the weight, CG location, and flight characteristics are compared to my existing Cici.
Some interesting differences discovered between this initial version and the later “second gen” version:
> Both the canard and rudders are not 1/16” balsa but actually 3/32”
> The motor tube is 2” in length, not 2.5”.
> The nose cone is actually 2” in length, not 1.75” in length.
(I was relying on dimensions for the above from penciled in notes on a Cici instruction sheet I downloaded. These were probably estimates handwritten by the builder who submitted the instruction sheet. Fortunately I have an original kit so I was able to accurately measure every part).
> The Wingspan is less than on the “second gen” later version (by a significant 3 1/4”).
> The other most obvious change is that the motor pod is mounted to the side of the fuselage front atop the canard wing, so it’s actually offset to the glider’s centerline. This was probably done to ameliorate the tendency of the ejection charge to snap the fuse, as the pylon and fuse are now effectively doubled in thickness.
> This earlier version has the main wing mounted under the fuselage, whereas the later version’s main wing is above the fuselage. (Probably has no impact on the CG location and weight distribution).
It’ll be interesting to see if these things have an impact on this Cici’s final weight distribution (CG point after trimming).
Since I build primarily gliders, one of the “gotchas” I always run into is getting the motor pod glued on straight using only the eyeball app (prone to a finicky accuracy rate). I finally got around to fabricating a ridiculously simple jig that I can use for all my RG builds. Should’ve done it sooner and saved a lot of time and exasperation.
I’ve decided to initially keep things completely “stock” (i.e., no rounding of wing or canard edges, no tissuing, no airfoiling, no doping surfaces etc.) just to see what the weight, CG location, and flight characteristics are compared to my existing Cici.
Some interesting differences discovered between this initial version and the later “second gen” version:
> Both the canard and rudders are not 1/16” balsa but actually 3/32”
> The motor tube is 2” in length, not 2.5”.
> The nose cone is actually 2” in length, not 1.75” in length.
(I was relying on dimensions for the above from penciled in notes on a Cici instruction sheet I downloaded. These were probably estimates handwritten by the builder who submitted the instruction sheet. Fortunately I have an original kit so I was able to accurately measure every part).
> The Wingspan is less than on the “second gen” later version (by a significant 3 1/4”).
> The other most obvious change is that the motor pod is mounted to the side of the fuselage front atop the canard wing, so it’s actually offset to the glider’s centerline. This was probably done to ameliorate the tendency of the ejection charge to snap the fuse, as the pylon and fuse are now effectively doubled in thickness.
> This earlier version has the main wing mounted under the fuselage, whereas the later version’s main wing is above the fuselage. (Probably has no impact on the CG location and weight distribution).
It’ll be interesting to see if these things have an impact on this Cici’s final weight distribution (CG point after trimming).
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Just finalizing a few things. Balsa nose cone had a pre-drilled shoulder for a dowel to anchor the shock cord in, so I decided to seal and protect the end from the ejection charge with a thin piece of epoxied-in aluminum.
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Had an opportunity to do some trimming when a low-wind opportunity came up unexpectedly.
Original version Cici CG point: 5/16” in front of leading apex of main wing.
Second gen Cici CG point: at forward apex of main wing.
Weight, bare balsa original Cici (this kit): 19.54g including 2.91g of tail weight.
Weight, “second gen” Cici: 31.77g including 4.88g of tail weight.
…to be continued.
Original version Cici CG point: 5/16” in front of leading apex of main wing.
Second gen Cici CG point: at forward apex of main wing.
Weight, bare balsa original Cici (this kit): 19.54g including 2.91g of tail weight.
Weight, “second gen” Cici: 31.77g including 4.88g of tail weight.
…to be continued.
waltr
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Wow, that is a pretty big difference in the weight.
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Probably mostly due to the extra 3 1/4" of wingspan and reinforced pylon on the "2nd gen" Cici which was released later.
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Original and 2nd gen Cicis. The most obvious difference is the larger wingspan on the later model, as mentioned earlier.
The one thing they have in common is a nose-heavy condition that requires tail weight. I find it odd that old reviews never mention this condition, much less the need for trimming. Maybe I’m too picky about having a smooth and shallow glide path, so I’m guessing that an untrimmed Cici will glide, though its descent would probably be far steeper and much more rapid, and its time aloft correspondingly shorter.
To be fair though, I’m going to remove the tail weight I attached during my trimming session and launch it as soon as weather conditions permit to see how it behaves box-stock. (With hurricane Nicole approaching as well as winter, it may be awhile).
…to be continued.
The one thing they have in common is a nose-heavy condition that requires tail weight. I find it odd that old reviews never mention this condition, much less the need for trimming. Maybe I’m too picky about having a smooth and shallow glide path, so I’m guessing that an untrimmed Cici will glide, though its descent would probably be far steeper and much more rapid, and its time aloft correspondingly shorter.
To be fair though, I’m going to remove the tail weight I attached during my trimming session and launch it as soon as weather conditions permit to see how it behaves box-stock. (With hurricane Nicole approaching as well as winter, it may be awhile).
…to be continued.
waltr
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Just a thought...
Would moving the pod rearward a bit avoid needing tail weight?
I would think that even with pod back an inch it will still launch straight.
Would moving the pod rearward a bit avoid needing tail weight?
I would think that even with pod back an inch it will still launch straight.
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Probably would. Too late now though, the pod's epoxied on and trying to remove it now would likely destroy or damage the pod and pylon/fuselage. Anyway I'm curious to see how the Cici will perform completely unchanged as sold.
waltr
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Yep, not on this one but maybe next one.
Currently waiting for your test flight video.....
Currently waiting for your test flight video.....
I built and flew many CiCis and all the other Edmonds kits. I don't remember any nose heavy needs rail weight, they all balanced exquisitely well.
But I do remember he was very particular about the grade and consistency of balsa, it was a little lighter than the densest stuff.
Others have noted similar things in their efforts to clone some designs, like Ecee Thunder.
But I do remember he was very particular about the grade and consistency of balsa, it was a little lighter than the densest stuff.
Others have noted similar things in their efforts to clone some designs, like Ecee Thunder.
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hard to fix once built.
seems like an ”a priori” solution would be to start with a longer body tube (nose cone further forward) when you build it, so it is likely to be effectively “nose” heavy, although ACTUAL additional mass is simply tubing, the CG is affected mainly by the LENGTH rather than the weight.
trimming in this case (since it is going to be nose heavy) would involve actual ”trimming”, cutting off forwar slips of body tube (BEFORE gluing in cone) until you get the right CG for a good glide. Could even use a tight external tape wrap to actual test fly it before finally gluing the cone in.
seems like an ”a priori” solution would be to start with a longer body tube (nose cone further forward) when you build it, so it is likely to be effectively “nose” heavy, although ACTUAL additional mass is simply tubing, the CG is affected mainly by the LENGTH rather than the weight.
trimming in this case (since it is going to be nose heavy) would involve actual ”trimming”, cutting off forwar slips of body tube (BEFORE gluing in cone) until you get the right CG for a good glide. Could even use a tight external tape wrap to actual test fly it before finally gluing the cone in.
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Huh? Sounds counterintuitive (unless I’m misunderstanding). CG is dependent on center of mass, determined by weight distribution along it's longitudinal axis once in glide mode, so the longer the motor tube, the further forward will be the glider's overall CG, which is the primary problem I'm confronted with.
The motor tube is already a pretty minimal 2.0", so maybe substituting a lighter plastic NC like Apogee's hollow vacu-formed styrene cone might help.
At any rate, I'm going to fly it completely "stock" (i.e., no rear ballast, completely unmodified) to see how it flies straight out of an original kit bag. As mentioned earlier, my assumption is that it will glide stably, though probably not as well as a trimmed version.
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You got me. I am thinking backwards. If you are having to add tail weight, then the bird is nose heavy and lengthening it is the LAST thing you want. Can you make it SHORTER? That might affect boost stability negatively as it will move motor back. My bad.
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Update:
Had a chance to do a test flight of the totally stock vintage kit 1st gen Cici on a B4-2, and as I suspected, it glides stably, but with a short-duration, nose-down descent. You can tell from the video’s time stamp (6 second – 20 seconds) that it was only aloft for 14 seconds before I started to walk over to retrieve it. It definitely would benefit from that 2.91 grams of tail weight to keep its nose from pitching down so much.
That said, it’s still an easy to build, sturdy, reliable and fun small-field flyer that I would have no concerns about launching on a C6-3.
Had a chance to do a test flight of the totally stock vintage kit 1st gen Cici on a B4-2, and as I suspected, it glides stably, but with a short-duration, nose-down descent. You can tell from the video’s time stamp (6 second – 20 seconds) that it was only aloft for 14 seconds before I started to walk over to retrieve it. It definitely would benefit from that 2.91 grams of tail weight to keep its nose from pitching down so much.
That said, it’s still an easy to build, sturdy, reliable and fun small-field flyer that I would have no concerns about launching on a C6-3.
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