RCU Forums - View Single Post - what is the correct setting for the bot tail.

11-12-2012 | 11:24 AM

skylark-flier

Joined: Sep 2002

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From: VA, Luray

RE: what is the correct setting for the bot tail.

Quote:

ORIGINAL: tobydogs

thanks for the input guys. dave,i to would consider increasing the slot but it seems so close to the edge already. what does occure to me now but to late to change would be to redrill the rear pivot hole a little lower. i don't want to change the design as the stabalizer and wingalignement thatmust be set for optimum performance.

i spent some time studying the pictures i took and hope to attain some more down elevator with a little triming. the slot in the vertical fin i need to cut is done at the very top of the cutout,this is shown on the drawing.so i figure there really isn't that much movement needed. i most deffinantly will be putting spoilers in the wing and i am very glad you stated the 1" x3 bays as being enough to assit in bring the bot in for a landing. i have the wings built and am going with the 2 pc designe.....now i'm wishing i hadn't used the metal joining rod that has a little play. i may try several coats of paint to snug its fit.

dave ,do you use any bands to hold your wing halves together other than the ones holding down to the fuse. i read some folk use a screw on each half on the underside thats hidden in the fuse and join them together with "o" rings like used on prop savers. seems like a great and easy way to go.

must say though, i was hoping more builders of the bot would share their experience setting trims for the bot in flight....do you set the elevator to be horizontial with the bottom of the fuse or is it set differently for getting level flight.[example:it has up elevator dialed in for level flight]any further discription of how it shoul look will be helpful, thanks gang,stu

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fficedocumentsettings></xml><![endif]>Hey Stu! Yeah, the slot’s close but not to worry. When I did my throw increase I simply cut out what I needed (which DID cut the LE almost in half) and then used CA on the LE, inside and outside, to re-strengthen it. Worked like a charm, no weakness anywhere. I had considered exactly what you said, re-drill the holes and move the whole thing back a bit, but decided to try it first with the stock settings. Glad I did. The structure of the whole vertical fin helps a lot in this regard – being solid sheeted. The sheeting actually gives the fin much of its strength, and you’re only cutting a tiny bit out of the sheeting comparatively. CA’ing the LE pretty much puts everything back to the strength it originally had.BTW, sorry this is so late (my reply). I’d typed the whole thing out, TWICE, and hit the wrong button, TWICE, erasing everything. Had to sit back for a couple days until I cooled down a bit from my own stupidity.TRIM – actually, there’s not a whole lot to trim on this bird. I found that I DO push the trim forward from “flying center” for launch, and it helps further, but once you’ve got the bird trimmed to ‘flying center’, you’ll use the trims very little. During normal flight I hardly have to touch the elevator controls to get a large amount of up/down response on the plane. That’s pretty much a normal thing with full-flying control surfaces – very high efficiency with little input. I once had (and still wish I had) an Airtronics Aquila that had full flying tail, rudder and elevator. The 100” wing on that critter was fabulous, the full-flying tail even better. She could literally turn on her wingtip and 15’ loops were quite normal. My BoT can do roughly 25’ loops, but the wing bends a bit much on the tighter maneuvers like that – makes me distinctly “jittery” watching the flex.Ah, yes – the spoilers. Just be sure to use the outside 3 bays. Mine are on the inside bays and it interferes with the elevators if I extend them too far. Doesn’t happen with the outside 3 bays. Have heard that from several other BoT fliers, as well as others who fly other planes with spoilers. Hadn’t thought about it when I built my bird. Wish I had though.Not sure what you’re talking about with the wing 2-piece design. If you’re referring to the ARF’s version with the solid (1 piece) center and the outer tips being plugged-in, you definitely wouldn’t want to do that. The added weight, especially being so far out on the wing, would make her rather hard to maneuver due to momentum factors. She’s hard enough to turn as it is.Not to worry about the “play” on the steel rods, either main wing or tail – never really becomes much of a factor in anything. After a rather short time, the rods get a slight layer of rust on them (you can hardly see it but it’s there) and that provides great holding ability. My own bird has a tendency to loosen the left side of the elevator during a whole days flying but it’s never been more than about a ¼” slip and all I ever have to do is push them back together a bit. That’s after flying ALL DAY!!Nope, no bands on my bird. I use 4 nylon bolts (2 in each wing), always have for my gliders. Doesn’t take much to do it, just a piece of ply epoxied inside the wing (front and rear) for the bolts to go through does it nicey. Got a decent pic of the set-up at http://www.wanderings-ds.com/images/...e/100_0382.jpg - - front bolts are actually inside the wing, rears are flush with the surface. In the pic they’re still white but I’ve since painted them to match the wing.Your idea of the “O” rings is a good one. If you finally decide to go with bands, that would be the only way to go. My own Butterfly is held on with bands and I use a hook & screw to hold them together – very similar to your “O” rings.There are several BoT threads on RCU that you might take a look-see at. One of the better ones is the “Big Wing Buildalong” at http://www.rcuniverse.com/forum/m_93...tm.htm#9347511 - - the guys there gave me a lot of help when I built my BoT.For initial flight testing, I’d just dial in the center of the original slot for the elevator. That’s awful close to where she should be for flight. I know my own BoT stays there about 95% of the time.Guamflyer is 100% correct on his numbers. Rudder MUST be set for max deflection. You’re gonna need it. I’d be interested in seeing the set-up for the rudder/spoilers too – sounds very interesting.One other item, and probably most critical with the BoT is balance. Make sure you’re not tail-heavy. My own BoT is the GP kit and no matter how much I sanded I ended up tail-heavy. Had to eventually add 6 oz to the nose – ABOVE AND BEYOND what was already there when I built her. That was in the form of 12 bullet weights under the battery pack, epoxied into the bottom after I hollowed it out from the outside. If I ever build another, I plan to add to the length of the nose to help compensate for that little item – probably about 2” or so.One more item, and I’m the only person I know that’s ever done it – a bit of a “chin” under the nose. The tow hook sticks out the bottom a fair amount and I’ve got the darnest luck at breaking them when landing. Seems that if there’s a rock anywhere in a field, I’m going to find it. While building my bird, I added a bit of a chin under her nose and increased the length of her tail-skid (actually doubled it) to get her hook clear of the ground. Seems to have worked, as I haven’t broken a hook yet. Pics of the chin are at http://www.wanderings-ds.com/images/...e/100_0426.jpg and http://www.wanderings-ds.com/images/.../100_0401a.jpgHook placement: I may be unique in this item, but I found that the stock hook set-up (location) just doesn’t do for my bird. If I use the front hole I have to “horse” her up. Second hole puts her into a vertical climb so steep she actually comes off the hook. I added a hole between them and it seems to be just fine that way. Like I said, I may be the only one around with this issue.She’s a good bird, great soarer, quite majestic in the air. You’re gonna enjoy her a lot. Just be sure to keep us up-to-date.Dave

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