> Just purchased a 2M Chrysalis from the DJ Aerotech booth at the Toledo > Expo, and am curious if anyone here has built one, and what your > construction experience was. Just finished my Chrysalis 2M. It's a very well documented and complete kit; an easy build; mine looks fabulous (and it's the first kit I've built since I was a kid). First flight tomorrow, if the weather holds up. Had one small problem with the control linkages which Don Stackhouse helped me resolve by email. I'm taking the liberty of reproducing Don's message below; it shows how helpful and professional these guys are. ------------------------------------------------------------- Gordon Braun-Woodbury asks: >I'm having a small problem in completing my Chrysalis 2M kit. I installed the nylon pushrod guides as shown in the plan, exiting the fuse at the rear. I drilled holes for the guides at a shallow angle through the fuse. Now, when I insert the pushrods through the guides, they appear to bind where the guides exit the fuse. They will slide in the guides, but only with considerable effort. Can you suggest a fix? I don't want to burn out my servos. < This is an excellent question. Fortunately there's a good answer for it. (even I get lucky sometimes!) The key to cause of your problem is in the change we made a while back in the pushrod material. The original Chrysalis 2-meter used flexible steel cable pushrods, which would handle the situation you describe with no trouble. Unfortunately, that same flexibility would allow them to flex too much if there was even the tiniest bit too much unsupported cable between the end of the guide tube and the servo or control horn. The resulting flex in the control linkages was a major cause of control surface flutter. This could be fixed by tinning the cable in the unsupported section, stiffening it in that specific trouble spot. However, this too was a somewhat tricky operation that could cause trouble for beginners as well. We decided that the best fix was to switch to music wire instead of flex cable. It cost us a HUGE amount of money to buy a special-length batch of music wire (normally it only comes in lengths of 36") that was long nough for the Chrysalis 2-meter fuselage. We now have enough of this special-length wire to last us a VERY long time! The naturally stiff music wire fixed the flutter and flexibility problem, but this same stiffness made it less cooperative when the cable had to go around a curve, such as in the tail of your model, or in the spoiler linkages. Fortunately the fix is fairly simple. The fundamental problem is that the STRAIGHT wire is being forced to go through a CURVED tube. It takes force against the insides of the tube to flex the wire into the curved shape, and that force is creating the friction. All you have to do is to first pre-curve the music wire into approximately the same shape as the tube you're running it through. Pull the wire out of the tube and hold it against the outside of the fuselage, so that the aft end is about even with where it will couple to the control horn (if the wire has a Z-bend in the end of it, make sure the Z-bend is pointing the same direction it will be when the Z-bend is installed in the control horn). Visualize the curved shape of the tube inside the fuselage and identify which section of the pushrod wire needs to be curved to match it. Hold the wire in your hand, like the way you would hold a knife or a spoon, but with your thumb pulled back so that the ball of your thumb rests on the wire about midway between your first and second fingers. The ball of your thumb should be located at the forward end of the section of the wire you want to curve. Now, squeeze (don't squeeze too hard on this first try, it's easier to curve the wire some more than it is to straighten it once it's curved!) with your thumb and fingers so that they wrap the wire into a curve around the ball of your thumb, and slide your hand along the wire till the ball of your thumb reaches the other end of the section of the wire you want to pre-curve. Look at the wire. Is it curved a little, or is it still straight? If it's still straight, try it again, only squeeze a LITTLE harder this time. Keep trying till you get a little curve in the wire, then continue using about that same amount of squeeze and additional passes through your hand until you get the curve you want. As you do this it's also a good idea to periodically slide the wire back into its position in the tube to check the friction. It will be even more difficult at first to push the wire through the tube, but as the curved part of the wire reaches the curved part of the tube, it will suddenly get MUCH easier. Keep experimenting with additional pre-curve till the wire slides sufficiently freely in the tube. You may find that the wire runs freely but now exits the tube at a weird angle, and binds in the tube exit when you flex it back to align with the hole in the control horn. Just pre-curve the wire between the end of the tube and the horn (leaving a little room between the end of the tube and the start of the pre-curved, to allow for the back-and-forth motion of the pushrod), so that it naturally holds that curve, instead of having to be sprung into that shape by force. Properly done, the resulting friction can be nearly as low as with a perfectly straight pushrod and tube, but without the flex and buckling problems of a flexible cable. Don Don Stackhouse @ DJ Aerotech [EMAIL PROTECTED] http://www.bright.net/~djwerks/ ----- Original Message ----- From: JIM MARTIN <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Saturday, April 08, 2000 7:20 PM Subject: [RCSE] 2M Chysallis build history > Just purchased a 2M Chrysallis from the DJ Aerotech booth at the Toledo > Expo, and am curious if anyone here has built one, and what your > construction experience was. > > BTW, I have to agree with Marc Gellart ( a fellow L.O.F.T. member, and > president of this outstanding club !!), the Toledo show was a terrific > experience for me, and the amount of technology and information available > was just simply overwhelming !! What a great way to spend a day. > > Jim Martin > New Haven, Indiana > > RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
