[RCSE] Re: large servos on full flying stab
On a larger model like the ICON, guys have been using the JR DS 3421 on the stab, another nice digital servo from JR. I was always puzzled a little by recommendations to use a mighty servo on the full flying stab. I totally understand the need for precision here (digital servos), but why use a very powerfull servo? If the stab pivots around its aerodynamic center and has a symmetric airfoil (both are true in 99.9% cases, including ICON I assume), then the control moments on the stab are near zero. The loads on the stab servo are miniscule compared to those of a flap servo. Am I wrong here? Oleg. RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED]
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Re: [RCSE] Interesting fact about New Volz Micro Maxx X series
In a message dated 7/16/02 2:28:55 PM Central Daylight Time, [EMAIL PROTECTED] writes: May I asked how you do that? Are you moving the control surfaces with your hand and then looking for what?? I dont think mild/ slow activation of a servo to hear the gears do that unified clicking hurts anything. And,just making sure that the servo is still rigidly mounted and that the arm looks to be in one piece. I blew a spline partially on a servo arm after a mid air at the F3J team select last year. There was no way finding that problem until the arm decided to stay in its own positions after launch and during the next landing.. Richard RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED]
Re: [RCSE] Interesting fact about New Volz Micro Maxx Xseries
Tony, You are right you should never man-handle a servo by manipulating the surface. I gently move the surface to look for gear problems. If you apply a quick rotation or quickly change direction you may damage the nylon gear used as a fuse in a metal gear servo. Never push a Flap to full deflection=over center, and then manually try to return the flap.What I do is feel the sevos mesh looking for smooth operation. If you suspect a damaged gear move the surface away from center and turn your radio on. Move the surface you suspect by radio command. A damged servo will usally grind and or respond with a jerky motion and gradually lose its ability to hold center. Best wishes Larry RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED]
Re: [RCSE] Re: large servos on full flying stab
What are the forces on a stab during a zoom or F3J launch? Are there other forces in action here? The force that cause tail booms to break. Probably the most damaging, a dork landing, many a elevator servos give up there. On Tue, 16 Jul 2002 15:42:40 -0400 (EDT) Oleg Golovidov [EMAIL PROTECTED] wrote: On a larger model like the ICON, guys have been using the JR DS 3421 on the stab, another nice digital servo from JR. I was always puzzled a little by recommendations to use a mighty servo on the full flying stab. I totally understand the need for precision here (digital servos), but why use a very powerfull servo? If the stab pivots around its aerodynamic center and has a symmetric airfoil (both are true in 99.9% cases, including ICON I assume), then the control moments on the stab are near zero. The loads on the stab servo are miniscule compared to those of a flap servo. RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED]
[RCSE] RE: Soaring V1 #576
Just Take off the Prop, or better yet leave it on. Slopes just great w/o power. Jeff F Date: Mon, 15 Jul 2002 17:41:06 -0300 From: mariano nunez [EMAIL PROTECTED] To: RCSE [EMAIL PROTECTED] Subject: zagi question. Message-ID: 010301c22c3f$f1a242e0$[EMAIL PROTECTED] Have you got some experience flying the zagi 400 in slope? Not with the motor off, without the motor and the 8cell pack -but with a standard 4cell pack... ;o) I have to change the CG? May be add some ballast? TIA. MARIANO NUNEZ [EMAIL PROTECTED] RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED]
RE: [RCSE] New Hitec Wing servos (and Volz Wing Maxx)
Hello Everyone, May I start by thanking Adam Till for his subsequent messages explaining in more detail the reported failure of the 5125. We at Hitec (and I suspect the whole soaring community) will be watching for any failure trend that develops concerning this product. As for the 5125 in question, can we have sent back to our service department for evaluation? I will see that a new one is forwarded to the owner. We do track all the failure points of every returned product, so we can spot any chronic flaws. Glen Merritt Marketing Director Hitec USA Phone # 858-748-6948 x310 Fax # 858-748-1767 -Original Message- From: Simon Van Leeuwen [mailto:[EMAIL PROTECTED]] Sent: Tuesday, July 16, 2002 10:12 AM To: Adam Kenneth Till Cc: Glen; 'Ben Diss'; 'plenard'; 'RCSE' Subject: Re: [RCSE] New Hitec Wing servos (and Volz Wing Maxx) HITEC Indeed a 5125 did start to melt the servo cover this last weekend, but to say that the servo in question caused the crash would be erroneous and misleading. In fact, a crash had occurred that caused enough of a bind on this particular servo's control surface to cause it to overheat. Given the digital electronics and associated update-rate, and low (thermal) mass of the servo itself, and the fact it was running on two 5-cell packs (redundancy), it's no wonder it complained (loudly). Under normal flying loads, these servos operate satisfactory. Any (digital) servo subject to undo loads as a result of a crash (or otherwise) could be expected to react in the very same manner. In other words...don't doodle on the way to the crash site if you use digital servos. VOLZ Indeed early versions of the Wing Maxx exhibited centering issues, and through testing showed temperature-specific drift in the amp design. This made for constant re-centering on most trips to the field. Although not widely known, a higher quality ceramic capacitor was offered as a fix, but required SMT-level soldering skills. Installing this, and the results, were less than stellar however. The PCB has since been updated. As predicted, Michael will be releasing a digital versions of their servo line-up, which might bring them up to on-par performance with their counterparts. As always, we will have to wait and see. Adam Kenneth Till wrote: Nope, not the case I meant. This was in the outboard aileron of a 4m Salto. The airplane didn't quite make it back to the airfield after an aborted aerotow, and put down (relatively hard) in a farmers field. The aileron didn't have anything to do with the forced landing...gravity did. The Salto was found resting with one tip on a pile of dirt, and smoke was pouring from the tip. The servo motor had burned through the case of the servo AND the case of the mount. This isn't exactly an inappropriate application...and I resent having been dismissed as a gossip-monger. Cheers, Adam It's a big mistake to allow any mechanical object to realize that you are in a hurry. The trouble with doing something right the first time is that nobody appreciates how difficult it was. - On Mon, 15 Jul 2002, Glen wrote: Hi Guys, How about the rest of the story. We at Hitec are aware of a HS-5125MG failing in flight in the manor described by Mr. Till while being used as the elevator servo on a 15-17 pound turbine powered jet model. Would Mr. Till be willing to confirm this is the case to which he is referring to? If this is the failure in question, I would have the modeling public know the application of the 5125MG was inappropriate. Digital circuitry in a servo rated at 49oz/in does not make the servo magical and thus capable of over coming the very strict and unyielding laws of physics. There is an old saying use the right tool for the job, it is clear the 5125MG was not the correct servo for the elevator of that heavy plane. Ladies and Gentleman please learn from this mistake so it is not replicated elsewhere. It is regrettable anytime a expensive plane goes in for a mechanical reasons, it is further regrettable a good, solid product such as the Hitec 5125MG is defamed through gossip on the internet. Glen Merritt Marketing Director Hitec USA Phone # 858-748-6948 x310 Fax # 858-748-1767 -Original Message- From: Adam Kenneth Till [mailto:[EMAIL PROTECTED]] Sent: Sunday, July 14, 2002 6:44 PM To: Ben Diss Cc: plenard; RCSE Subject: Re: [RCSE] New Hitec Wing servos (125MG and 5125MG-Digital) Having recently seen one burn a hole through it's case and cover after a surface was jammed, I wouldn't touch them with a 10 foot pole. I think they have current draw issues. Cheers, Adam Till It's a big mistake to allow any mechanical object to realize
RE: [RCSE] Re: large servos on full flying stab
Oleg, Your AC assumptions are correct, but the powerful servo is really required when the plane is under high load, IE: on tow and during high G maneuvers. Under those conditions the loads on the stabs are immense and cause binding and friction in the stab pivot mechanism. Plus it's the only control surface on the plane that if it fails you're assured of crashing. (No redundancy) Go set a few pounds of weight on each side of the stab on your open class ship and see how well the elev servo pivots it. Norm PBSS -Original Message- From: Oleg Golovidov [mailto:[EMAIL PROTECTED]] Sent: Tuesday, July 16, 2002 12:43 PM To: [EMAIL PROTECTED] Subject: [RCSE] Re: large servos on full flying stab On a larger model like the ICON, guys have been using the JR DS 3421 on the stab, another nice digital servo from JR. I was always puzzled a little by recommendations to use a mighty servo on the full flying stab. I totally understand the need for precision here (digital servos), but why use a very powerfull servo? If the stab pivots around its aerodynamic center and has a symmetric airfoil (both are true in 99.9% cases, including ICON I assume), then the control moments on the stab are near zero. The loads on the stab servo are miniscule compared to those of a flap servo. Am I wrong here? Oleg. 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]
Re: [RCSE] large servos on full flying stab
I understand your point. Yes, at the aerodynamic center of the stab the forces are ideally zero. However, the realities of daily life are also present. While level flight is somewhat static, much of the time the plane is in a much more dynamic mode. Whether due to a wind gust or inputs from the pilot, the tail is often trying to change the AOA of the wing. Additionally the tail is nearly always countering the pitching moment of the wing which varies with flight condition. All the above results in average loads and peak loads on the tail, and thus the servo, which can be significant. This along with the devastating effects of elevator failure leads pilots to be excessively concerned about their choice of elevator servo. Bill Swingle [EMAIL PROTECTED] Janesville, CA RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED]
[RCSE] Re: Aluminum joiner material
In a message dated 7/16/02 10:24:48 AM, [EMAIL PROTECTED] writes: Date: Tue, 16 Jul 2002 05:52:43 -0700 (PDT) From: Jeb Bushell [EMAIL PROTECTED] To: RCSE [EMAIL PROTECTED] Subject: Which Aluminum For Wing Rod? Message-ID: [EMAIL PROTECTED] I need to make a set of wing joiners for a 3-piece wing. These need to be 0.5 OD aluminum tube, like the originally supplied set. Aircraft Spruce has aluminum tube in 5052-0 , 6061-0 and 6061T6. Which of these will take a 5 degree bend and a little filing and make the best joiner? Many thanks, Jeb Bushell. Jeb, I would go for the 6061 T6. It will take the 5 degree bend fine (form it around a radius rather than a vise jaw) and be stiff enough without further treatment. Wall thickness is important here also. I would want at least .065 wall. Regards, Walt Dimick I.R.F. Machine Works * Have you checked out I.R.F. Machine Works' precision and heavy duty ac cessories for rotary flap and aileron drivers? The components for this totally clean and hidden system for moving control surfaces are now available premanufactured. Get the scoop for your next building project at our RDS web site: http://www.irfmachineworks.com/rds **I.R.F. also builds the Little Big Winch, a complete, personal launching system for RC sailplanes up to 3.5 meters. http://www.irfmachineworks.com/lbwinch * RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED]
Re: [RCSE] New Hitec Wing servos (and Volz Wing Maxx)
Gotta jump in on this one. Last year I flew my brand new 1/3 scale Duo Discus for the first time at the Triple Tree Aerotow, in Greenville SC. Nothing like doing the first flight in front of a crowd. Well this crowd included Peter Goldsmith (I think he even towed me up), who is a muckey muck with Horizon. They are the good people who bring JR products to us. Very quickly after release from the tug, I figured something was really wrong with the plane. I had vague control. I managed to get it back along a path over the runway with the hope of landing out at the top end of the sloping runway. As it went by at about 40 feet over our heads we could all see the elevator waggling to beat the band. That was a very pricey JR 8411 servo in there. I eventually got it down in a rather abrupt manner near the crest of the sloping runway. Abrupt is a kind description for the belly flop that occurred. Upon arrival at the site, I had already decided that the JR product was my point of failure and I was letting it be known to all. Once I got to the plane, the gears in that servo were clearly goners. As I carried the plane back along the line I really made an ass of myself by shouting at Peter to come figure out what had failed. He was waaay cool. He asked, Did you range check this before you flew it? No, was about the best I could do. Why don't we check that out was Peter's suggestion. I only got about 10 paces away from the ship with my transmitter before the plane started that sickly jittering. I had simply grabbed a RX off the workbench and stuck it in the plane in my haste to finish the project. I really to this day can't say if it was on the workbench because it had been removed for cause from it's prior home. Even after my behavior, Peter was incredibly kind to replace the stripped 8411 so that I could fly again the next day. I can't say enough about Peter's representation of his product. Same applies to the people at Hitec to whom I have returned lots of fried out, stripped, or otherwise mangled gear and from whom I get repaired/replaced items in no time. No questions asked. After a crash, I am always disappointed. It is very easy to blame the products that seem to have gotten in the way. But most of the time, the company will be very professional and back their product, whether or not it was at fault. JR and Hitec certainly do. Now those blue things are another story. Cottage industry stuff with a cottage industry support system (in the past, don't know what they have set up today) is an invitation to disappointment. Yeah, they sent me the shafts after mine failed. Would have been really nice to have gotten the word before I committed a $750 plane to them. I seem to be saying this a lot lately, but here goes again. The truth may often be stranger than fiction, but it will never hurt your reputation like a cover up. If quality is the true mantra of the blue guys, like their web site and evangelists say it is, why don't they indicate a recall or safety directive on these servos? Will my servos be swapped out for new if I send them back? Or will I be told that the problems just couldn't be, like I was told, in person, when I presented the problem to the factory rep? I feel better now. :) Lee Estingoy Overland Park, KS - Original Message - From: Glen [EMAIL PROTECTED] To: [EMAIL PROTECTED]; 'Adam Kenneth Till' [EMAIL PROTECTED] Cc: 'Ben Diss' [EMAIL PROTECTED]; 'plenard' [EMAIL PROTECTED]; 'RCSE' [EMAIL PROTECTED] Sent: Tuesday, July 16, 2002 12:43 PM Subject: RE: [RCSE] New Hitec Wing servos (and Volz Wing Maxx) Hello Everyone, May I start by thanking Adam Till for his subsequent messages explaining in more detail the reported failure of the 5125. We at Hitec (and I suspect the whole soaring community) will be watching for any failure trend that develops concerning this product. As for the 5125 in question, can we have sent back to our service department for evaluation? I will see that a new one is forwarded to the owner. We do track all the failure points of every returned product, so we can spot any chronic flaws. Glen Merritt Marketing Director Hitec USA Phone # 858-748-6948 x310 Fax # 858-748-1767 -Original Message- From: Simon Van Leeuwen [mailto:[EMAIL PROTECTED]] Sent: Tuesday, July 16, 2002 10:12 AM To: Adam Kenneth Till Cc: Glen; 'Ben Diss'; 'plenard'; 'RCSE' Subject: Re: [RCSE] New Hitec Wing servos (and Volz Wing Maxx) HITEC Indeed a 5125 did start to melt the servo cover this last weekend, but to say that the servo in question caused the crash would be erroneous and misleading. In fact, a crash had occurred that caused enough of a bind on this particular servo's control surface to cause it to overheat. Given the digital electronics and associated update-rate, and low (thermal) mass of the servo itself, and the fact it was running on two 5-cell packs (redundancy), it's no wonder it complained (loudly). Under normal
[RCSE] Planes for Sale
The following are for sale: 1. Artemis KC, blue/white. Includes 6 Volz MicroMaxx set up for Airtronics. Minor repair to nose, only in canopy area; no other damage or repairs. Includes custom made nose skeg and BagLady bag for fuse and covers for V-tail. $900 plus shipping. 2. F3B Diamond, red/white. Includes 5 Volz MicroMaxx (Ailerons, flaps, rudder) set up for Airtronics; stab servo not included. Minor hanger rash to one wingtip, no other damage. $700 plus shipping. Please contact me offline at [EMAIL PROTECTED] or (916) 984-5123. Jim Thomas RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED]
Re: [RCSE] Interesting fact about New Volz Micro Maxx Xseries
Thanks Larry, That tip could have probably saved my McV2. Steve On Tue, 16 Jul 2002 16:19:14 -0400 [EMAIL PROTECTED] wrote: Tony, You are right you should never man-handle a servo by manipulating the surface. I gently move the surface to look for gear problems. If you apply a quick rotation or quickly change direction you may damage the nylon gear used as a fuse in a metal gear servo. Never push a Flap to full deflection=over center, and then manually try to return the flap.What I do is feel the sevos mesh looking for smooth operation. If you suspect a damaged gear move the surface away from center and turn your radio on. Move the surface you suspect by radio command. A damged servo will usally grind and or respond with a jerky motion and gradually lose its ability to hold center. Best wishes Larry 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]
[RCSE] Dodgson Windsong
My boss has offered to sell me a Windsong kit his wife bought for him in Dec of '86. It's in mint condition with never even a stick having been removed from the box. What would be a fair price to offer him. Thanks, Bill RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED]
[RCSE] Glider performance at extrem high altitude.
John Ellias published some really good performance data for the RNR SB-XC ttp://www.xcsoaring.com/xcsoaring/articles/sbxctest.htm How would this performance change at extreme high altitude? 30,000ft, 60,000 ft etc It is my understanding that the indicated Air speed would remain constant, but true air speed would increase. Would the minimum sink speed scale by the same factor? Paul RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED]
[RCSE] Re: Control Slop on DLG's
To add to Rob's comment, I like to tear down the control system on my DLGs every couple hundred or so launches. I didn't do this in the past, but the more I fly, the pickier I get about it. I find that as time goes on, launch height and crispness of control on launch goes away sometimes slowly and imperceptibly. If you get to the point of flutter, you have WAY too much play. Any play will rob you of launch height and especially camber effectiveness way before the flutter is noticed. Pushrods can get fatigued also. They're cheap and fairly easy to change, so why not swap them out when things get a bit sloppy? It beats the heck out of replacing a $400 DLG that blew up on launch. If you launch hard, check for delams often around hingelines and don't tolerate any control slop. It will eventually ruin your day. Tom Siler Columbus, OH --- In [EMAIL PROTECTED], [EMAIL PROTECTED] wrote: Can flutter cause reduced launch height? Yes, it will. Not only can, but definitely will. Flutter uses up a huge amount of energy. Do the speed and forces of the DLG launch tend to pull the hinging apart? Certainly could. Check the hinges on any plane occasionally for slop. happy trails - Rob Glover I noticed the first item on Oleg's HLG seminar at Mid-south was having a tight control system. He went as far as suggestioning better quality servos. I had noticed the rudder on my DLG was not centering because of slop between wire and too large a hole in servo arm. I used Dave Darling's suggestion and closed up hole with CA. Also noticed that the glass on the vertical fin was pulling away from the balsa causing further slop in the surface. My questions are: Could flutter caused by excess slop reduce the launch height? It seemed like I got better height after fixing this. Do the speed and forces of the DLG launch tend to pull the hinging apart? Thanks for any replies, Bill Kuhl 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]
