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Feb 09, 2019, 03:00 PM
I Look, Listen, and Learn
Timbo383's Avatar
Quote:
Originally Posted by springer
Sounds like a reasonable position, since we don't really know how it will perform (if at all!)
Personally I think it'll fly good, I have more confidence since I played around with the cg some more with the chuck glider. I added more weight to the front and it glides even better now...go figure. A nice steady drop as it loses momentum.
Got my simpler version cut out and ready to glue on/in the bamboo and cf strips to stiffen the floppy dtf foam. I have some of that crappy stiffer foam I purchased from hobby king( half as good as mpf, but a tad better than dtf) that I got on sale at one time with no delivery charge, that I'll use on the next one if this works out after I've crashed it too many times to repair.
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Feb 09, 2019, 05:01 PM
treefinder
springer's Avatar
Thread OP
As I was working on mine today, I got to the elevator hookup, and discovered that it is a bear! I put the servo under the canard wing, and effectively blocked access. Fortunately I had not glued the wing/struts/canard unit to the fuse yet, so sized the wire length and hoped it would be ok after glueup. So far it looks to be. Probably should put that servo aft of elevator and battery in nose.

Also, did a hand toss (ailerons were both a bit up, not connected yet) and got just a tiny bit of up in the glide. This thing may fly! The struts are single thick st moment. Gonna need either :spars or double thickness, I think.
Last edited by springer; Feb 09, 2019 at 05:40 PM.
Feb 09, 2019, 07:15 PM
I Look, Listen, and Learn
Timbo383's Avatar
Here's a crude drawing of how I'm gonna "attempt" to hook up my elevator. Cut a slit for the push rod and horn in the fuse down elevator area and mount the servo in front under the canard. Don't know the specifics yet, and never done this but I think I can figure it out.
Feb 09, 2019, 11:32 PM
I Look, Listen, and Learn
Timbo383's Avatar
And here's the actual build, gonna be a short rod, thats for sure. Anyone know if it will or won't work? The battery door will be on the bottom and extend to the servo area in case I need to get to it for adjustments . Made sure to do that after Springer's oops. Thanks Mike...
Edit: after looking at it some more I relized the horn needs to be at the pivot of the elevator, may have to rethink this. Maybe turn the servo facing more up towards the pivot. Brain hurts, going to bed now.
Last edited by Timbo383; Feb 09, 2019 at 11:40 PM.
Feb 09, 2019, 11:55 PM
treefinder
springer's Avatar
Thread OP
Great minds. . . What you show is seriously close to what I did. The only real difference is that my servo is parallel to the wing surface. I got it all together, and found that the elevator took all its trim to get parallel to wing. I apparently moved the servo while installing the horn. Had to cut a 1" square hole in wing to get access and reset the horn. The better way for access would be to put servo behind the wing/elevator, but I found I needed it fwd for CG. Always a tradeoff. Battery (350-400mah) is about where you show yours, also for CG. Mine is all together. Glide test onto the bed is straight and gentle. Hopefully no wind early tomorrow and I'll try outside.
Feb 10, 2019, 12:31 AM
skumgummi dave
Feb 10, 2019, 07:36 AM
I Look, Listen, and Learn
Timbo383's Avatar
No mater how I moved my servo I can't get it to where I can access it...just like you...so I think I'll just mount it on top for simplicity. Also I think that sharp cut behind the elevator might give some turbulence, so I smoothed that out. May play with the servo some more to still hide the horn later when I get some time to it.

Edit: hmmm, I think I can mount it up front there in the battery tray area. The extra weight way up front means I don't need the battery all the foward.
Last edited by Timbo383; Feb 10, 2019 at 07:51 AM.
Feb 10, 2019, 09:02 AM
treefinder
springer's Avatar
Thread OP
Well, winds were low, temp not quite "bitter", and maiden not quite successful. She wanted to swing left into a diving turn before I could get fingers to stick. I did get one 2 second or so "flight" before the wing snapped mid air about 1/2 " from fuse. I had been concerned about strength of the struts, but they are un-damaged after several cartwheels and the wing is the failure point. Seems like lack of yaw stability, wierd, given the dihedral and sweep. I may try some tip fins this afternoon.
Feb 10, 2019, 11:20 AM
I Look, Listen, and Learn
Timbo383's Avatar
Bummer, that is weird considering you put in dihedral. Giving me doubts now about my flat wing. But good news for me. I got my servo and horn underneath afterall and thanks to your comment I installed a trap door for the servo before mounting the canard, so I should have an easier servo/horn connection than you had.
Feb 10, 2019, 12:18 PM
I Look, Listen, and Learn
Timbo383's Avatar
I'm gonna sound like I know what I'm talking about now.
With that large frontal area and no vertical stab I think that may be the problem. The tips would probably need to be a little on the large size to help, maybe just one stab in the middle on the fuse would be enough unless you don't want that kind of look for your plane. The large fins on the outside of my chuck glider must be what is keeping it stable in flight, so I'm going to raise mine up a little more on my plane then I had planned on just in case.

BTW you got it all together AND flown already....you win.
Last edited by Timbo383; Feb 10, 2019 at 02:38 PM.
Feb 10, 2019, 01:44 PM
treefinder
springer's Avatar
Thread OP
Not much of a win, when the end result is repairs!

The v stab might be a requirement, although I am running a 7x3.5 prop, so torque reaction may be an issue as well. More stuff to tinker with. . .
Feb 11, 2019, 04:36 AM
Registered User
agfrag's Avatar

Blended Wing Wing


My goodness, this design of yours has sure started a plethora of variant ideas!

Here's my latest, the Blended Wing Wing. I've got it about 90% built, and it may make it to this weeks indoor fly at Ultimate tomorrow...
using a K4 airfoil, and the center layer has a 1 by 3mm carbon strip bowed and embedded in a slot about 1/2 inch aft of the leading edge. Servo's will be close to the elevons, may have to use servo extensions.
Feb 11, 2019, 11:00 AM
treefinder
springer's Avatar
Thread OP
Fun and games!
Feb 12, 2019, 05:31 PM
treefinder
springer's Avatar
Thread OP
Agfrag, your wing flys a treat at USA today!

My canard, on the other hand "flew" short and goofy flights. I tried different props to see if motor torque was causing the yaw left into spin behavior. They had no effect. Took out all reflex from ailerons, helped a bit, but only in keeping nose level before the spins. I finally added 7 gram weight to nose, and that seemed to help, although I still spun it in after a 30 ft straight and level flight. Broke one strut and wing root again which ended tests for the day.

So, move CG fwd, probably reduce dihedral (which sort of defeats the blended wing idea), maybe make fuse longer. Back to drawing board. . .
Feb 13, 2019, 06:41 AM
I Look, Listen, and Learn
Timbo383's Avatar
Mike, have you thought about maybe decreasing the width of the struts? I'm just guessing because of my lack of aviation knowledge but could they be performing like front verticals? I'm not sure how much of an angle you have on yours but because mine is a flat wing mine are pretty steep.


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