RE: Merlin 2016 GloBee Style Plugs
[quote]Where are you buying Merlin Plugs? [/quote] [link=http://www.darrolcady.com]Darrol Cady Racing Supplies and Info[/link]
Posted on: 12/19/2009 9:07 AM by Author "StanDouglas" in the forum "Q-500 Racing"
http://www.rcuniverse.com/forum/fb.asp?m=9343050

RE: Bench running a TT40
The problem with the muffler bolt is an on going one. It is an expansion problem and users tend to over tighten the bolt which causes it to fail. Replacing it is a good idea. I use the magnum XLS 61 muffler bolt. Part # 120616 they're around $3.00. I bought several the last time I ordered. Another potential problem is the coil spring in the carburetor. The black retaining screw for the barrel sometimes works loose and when it does the barrel comes out allowing the spring to be ingested into the crank shaft ruining the engine It goes from +16K to 0K in 1/2 revolution! The fix is to remove the spring. It makes no difference in the engine performance. The retaining screw should also be secured with Loctite. In a pinch I have added a rubber band around the carb so as to hold the barrel in should the screw fall out. Rumors still persist about bearing failures, but of the 7 engines I have all but 1 have the original bearings and none have failed. On the 1 engine I replaced the bearings as an experiment with expensive precision bearings. I tacked the engine before and after and there was absolutely no detectable performance gain. Finally, it's always a good idea to tear your engine partially down and look for fillings, machining errors etc. before the first run. Should you find a machining problem I wouldn't mess with it return it to your source. I have had good experiences with ACE Hobby, Inc. They replaced one of my engines that had a connecting rod fail during a race. Stan D.
Posted on: 11/13/2009 10:10 AM by Author "StanDouglas" in the forum "Club 40"
http://www.rcuniverse.com/forum/fb.asp?m=9250732

RE: Club 40, AMA424,-USRA Sundowner Race in Austin, Texas RESCHEDULED!
It was a fun weekend and for once I was able to race as well as run the light system. We'll get the results posted soon. At this race the Paul Herman matrix program wasn't used going for pen and quill instead. So I don't have the results on a computer yet. Both the Club 40 and AMA 424 went off without a hitch and very little carnage. We had one hit the pylon after finishing the race, bummer. One mid air and take off collision, me, where the lane next to me launched on the wrong flag. In the 424 we even had turn lights using Fred French's wireless system that consists of an inexpensive Spectrum radio, DC motor controllers turning Sears 12V LED lanterns on and off. Worked great with no delay! We had lots of help from friends and were not hurting for officials which made it really nice. Lots of chairs available for spectators under a canopy for shade too. On Sunday we ran the Sun Downer event with in-air starts, like Warbird racing. This was a learning event for every one. The course set up was 1000' two pole. Due to attrition prior to actually racing we wound up with only 3 flyable airplanes. So 6 pilots shared the 3 airplanes! Amazingly after the end all three aircraft were intact. When there's a heat that's close it is really exciting and the drone of the engines is music. None of that high pitched whine of 22,000 rpm. I can't wait to see a fully populated Sun Downer race with 4 of those aircraft with their realistic sound droning around the course. At one point we had a dead stick at the far end of the course and the Sun Downer went into a pasture with horses. The horses started scattering before it landed. After it was retrieved they all came back and lined up at the fence and continued to watch the race. I thought on 1000' course it would be a bit boring, but it wasn't, they were turning around 12 seconds per lap and when those large airplanes swap positions in the air it's something to watch. The turn lights were positioned at the pylon for the 600' course and the officials at the 1000' pylon which worked out nicely. Just thought I'd post some thoughts and observations. Next up Fred's thinking of hosting a Giant Scale event in the fall. Stan
Posted on: 7/21/2009 9:53 AM by Author "StanDouglas" in the forum "General Racing Discussion"
http://www.rcuniverse.com/forum/fb.asp?m=8951484

RE: Club 40, AMA424,-USRA Sundowner Race in Austin, Texas RESCHEDULED!
I'll be checking out the lap lights this week and I am looking forward to seeing Fred's new turn lights. Guess I better dust off my Raider and Quik-V's. SD
Posted on: 5/31/2009 4:26 PM by Author "StanDouglas" in the forum "General Racing Discussion"
http://www.rcuniverse.com/forum/fb.asp?m=8814025

RE: 2008 Season C40 CHAMPIONSHIP-Nov1, 2008, AUSTIN, TX
The light system I built was designed and supplied by Hank Kauffmann. The actual display boards were supplied to me by Jim Allen who has been working closely with Hank to develop a race management system. The "Brain" of the system was also designed and built by Hank. The Brain takes the information from the the computer and converts it into data for a RS232 cable. At the light panel end there is an RS232 receiver chip that converts the data to control the logic there. So far I am able to control the lights from as far as 150'. This is more than enough for 2 pole racing. The Brain can be modified to use a wireless modem at some future time and to add wireless input from lap counters and cut judges. Currently the Brain only sends data to the light panels. It does not receive data from any stations. The Brain is however capable of sending information to the computer as does the NATS system. So it can be expanded to be fully wireless. I have taken a Logitek programmable game controller hacked it, soldered external connections, and mounted it in an enclosure with push buttons and phonojacks to allow lap counters to input laps. It will also accept cuts for all pylons. The Judgeman program has hooks in it to recognize the Logitek controller and substitute that for input from the Brain. The lap counters all have 6' cables that go to the Logitek controller. When cuts occur they must be radioed to a cut judge who inputs them through the controller buttons. The program then signals through the Brain to the light logic. There is more detail on the NMPRA website including pictures of some of the work I did on the Logitek controller. The RS232 cabled version is a low cost solution for those who don't need a full blown 3 pole race system. Although this cabled system might also work for three pole racing. I don't know what the limits are on the length of cable yet. The RS232 specs are something like 80', but we're not driving the RS232 very fast and as I said it works fine with 150' cable now. Cheers, Stan
Posted on: 10/23/2008 5:07 PM by Author "StanDouglas" in the forum "Club 40"
http://www.rcuniverse.com/forum/fb.asp?m=8078231

RE: 2008 Nats Updates
The NATS final results are posted on the NMPRA website: [link=http://www.nmpra.org/event_results/NATS-2008_combined_Results.htm]NATS 2008 Final Results 428 and 422[/link] Stan D.
Posted on: 7/20/2008 10:48 AM by Author "StanDouglas" in the forum "General Racing Discussion"
http://www.rcuniverse.com/forum/fb.asp?m=7751266

NATS Final Results
The NATS final results are posted on the NMPRA website: [link=http://www.nmpra.org/event_results/NATS-2008_combined_Results.htm]NATS 2008 Final Results 428 and 422[/link] Stan D.
Posted on: 7/20/2008 10:46 AM by Author "StanDouglas" in the forum "General Racing Discussion"
http://www.rcuniverse.com/forum/fb.asp?m=7751258

RE: Q40 Foam wing
In the Lyle Larson video, F1 No Secrets, he uses bass wood for the spar. He was taking those inexpensive yard sticks that hardware stores give away or sell for very little and planning them down as a spar with a Black & Decker planner to 1/16" thick. He cut them in 1/2 for 18" spar in each wing half, glued with Tite-Bond. He did not use carbon fiber and thought it added nothing to the strength over his less expensive techniques. The skins were set to the cores using Tite-Bond, no epoxy. The wing balsa skins are covered top and bottom with fiber glass using polyester resin. About the only real reason to go to molded wings over foam ones is the gain in consistency with a mold. Foam wing airfoils will vary from one to another due to many factors and a slight difference in the airfoil of even 1/128" at any point will change the various coefficients making some wings do better than others even though the cores are cut from the same templates. Doing a wing from foam cores reminds me of the surf board shaping masters; there were a lot of surf board makers, but only a few of them made really great custom boards. Lyle should resurrect his video. It had a lot of good building tips that were applicable to model building in general as well as Q40. Stan D. [color=#006600][b]"Whether you believe you can or you can't, either way you are right." [/b]Henry Ford[/color]
Posted on: 7/18/2008 12:12 PM by Author "StanDouglas" in the forum "Q-40 Racing"
http://www.rcuniverse.com/forum/fb.asp?m=7744449

RE: 2008 Nats Updates
The big NATS news is that there is a party tonight after the final with big steaks and lots to drink! Oh, and there are a least 4 guys who advanced to the final. Wow how underwhelming[:o]
Posted on: 7/17/2008 9:48 AM by Author "StanDouglas" in the forum "General Racing Discussion"
http://www.rcuniverse.com/forum/fb.asp?m=7740442

RE: Q500 aileron torque rods
I use 1/8" welding rod. Which I copied from the Neme-Q. I thread the ends 6-32 to accept the large horn brackets. The rod is heavy, but my Q500's come out under 3 1/2 lbs. I would suggest you need to look elsewhere to save weight. The Quik-V (Jim Allen design) starts the aileron at 5" from the center. Welding rod is relatively inexpensive. For bearings I use Dave Norman's method of epoxy and Crisco. You can see this method in his write up on the NMPRA.org website under Techniques/Skinned Hinges. While you're there take a look at the V-tail hinges by Bill Vargas. [link=http://www.nmpra.org/Documents/Skinned-hinges/Hinges.htm]Skinned Hinges Minnesota Style[/link] [link=http://www.nmpra.org/Documents/Skinned-hinges/Vargus/v-tail-hinges.html]V-Tail Skinned Hinges[/link] Stan D.
Posted on: 7/17/2008 9:38 AM by Author "StanDouglas" in the forum "Q-500 Racing"
http://www.rcuniverse.com/forum/fb.asp?m=7740409

RE: Making the change from 3 pole to 2 pole
The Judgeman program works very well for 2 pole racing. You simply don't use the cuts for pylon 3. And by locating the computer with the lap counters it makes it easy to set up without the expensive wire-less modems or long cable runs. RS232 doesn't work well over 80' to 100'. [quote]We have not tried a flying start except on my field using a 3 pole course. And that was just to get everyone in the air at their own pace. We started to go to an air start on Saturday, but we didn't have a count down mechanism.[/quote] I put an audio count down in the Judgeman program to support Warbird racing. Paul Herman supplied me with the actual audio. The audio works better than a visual count down because the pilots need not take their eyes off the aircraft. Paul also uses the same audio with a tape player. The only problem with it right now is I don't have a mechanism to hold the audio count. So you have to restart it from 60 seconds. When I find the time I plan to break the audio file into segments so that you can either reset to 60 seconds or hold at some lesser count. Stan D.
Posted on: 7/15/2008 9:11 AM by Author "StanDouglas" in the forum "Club 40"
http://www.rcuniverse.com/forum/fb.asp?m=7732954

RE: Making the change from 3 pole to 2 pole
Don, Instead of reinventing the wheel, why don't you take a look at what Hank Kauffmann and I have done with the Judgeman program and Hank's wire-less modems. I am using RS232 cables in my system to keep the cost down. Hank has developed boards that display the laps and cuts for each lane with LEDs bright enough for the starter and pilots/callers to see in the direct sun. These boards can be wired in parallel. Our system in Austin will have two sets of boards. One set for the pilot station and the other for the lap counters and interested spectators. Both sets will display the same info. There is a simple circuit/box that replaces the wire-less modems and if we ever decide to go wire-less all our displays will work by replacing the RS232 box (same boards as at the NATS and Speedworld.) The timing program records every lap for every lane as well as cuts and at which pylon in an ini file. At the end of a heat the heat can be printed out for examination by the officials for errors and finalizing. The program determines the finish order, but can be over ridden by the operator. Between heats you go go backwards and review previous heats by clicking a back arrow. At the end of the race you have the lap by lap record of every heat. There is an audio 60 second count down option that can be fed into a PA system for in-air starts, configurable lane color assignments and lots more. The software has been evolving for several years now and is being used at some of the major races including the second year at the NATS. For my RS232 version we are using a $19 Logitek USB programmable controller mounted in a box with phono jacks for the lane laps and pylon station cuts. I had to do this because the wire-less version controls these functions from various judging stations on the field. We still radio in cuts, but it would be pretty simple to run cables to the cut judges and have simple relays for amplifiers. I will run an RS232 cable 70' to pilot station. By using the Judgeman program I think you can contribute to making it even better. Plus if everyone has similar displays we can swap or borrow for various races. If our displays are the same there could be a spare at a contest or another display set up some where for the spectators etc. Did I mention the displays will also do the count down? There is also some talk about sensors in aircraft to do the laps and cuts with out humans and some effort has been expended and prototyped. Something to think about anyway. The program is down loadable from the NMPRA site. Jim Allen is currently working on a manual, but I can assist you in getting started. It has a manual mode that allows you run it with the mouse. Stan D
Posted on: 7/14/2008 5:35 PM by Author "StanDouglas" in the forum "Club 40"
http://www.rcuniverse.com/forum/fb.asp?m=7730555

RE: South Texas Club 40 HCAM Race Results?
The Hill Country Aero Modelers Club 40 race, Saturday July 12th are here: [link=http://www.nmpra.org/event_results/HCAM-July-2008.html]HCAM Club 40 Results July 12, 2008[/link] Ciao, Stan D.
Posted on: 7/14/2008 10:10 AM by Author "StanDouglas" in the forum "Club 40"
http://www.rcuniverse.com/forum/fb.asp?m=7729011

RE: Spinner or Prop Nut?
Prop nut is my choice
Posted on: 6/23/2008 10:42 AM by Author "StanDouglas" in the forum "Club 40"
http://www.rcuniverse.com/forum/fb.asp?m=7640950

RE: Ninja 500
I see Darrol Cady at www.darrolcady.com or [link=http://www.darrolcady.com]Darrol Cady Racing[/link] is also carrying the Ninja and has them in stock. He has one there that he painted the trim with a rattle can. He has a description of the assembly and paint effort. Looks good. SD
Posted on: 6/16/2008 9:31 AM by Author "StanDouglas" in the forum "Q-500 Racing"
http://www.rcuniverse.com/forum/fb.asp?m=7618818

RE: Q25 vs. Club 40 Challenge...
The light panels are getting closer to being implemented for the So. Texas racing. I should be receiving the boards to populate with electronics soon. The plan is to have two duplicate sets of displays. One will be located for the convenience of the starter, callers and pilots on a small A-frame stand. This will mainly allow the [b]starter and callers [/b]to be able to tell what the status of the race is at. No longer will you fly 15 laps and then find out you had a cut. The other display panel will be mostly for the benefit of the lap counters, but should also be visible by spectators and interested pilots who are not currently racing. In addition to indicating the laps and cut information the displays count down for the start as well. In my last race (before I had radio problems) in my second heat a pilot and caller walked off the start line as the count was almost finished completely blocking me from seeing it; this will eliminate that problem as well. The two displays have identical information during the race. [quote]In my view there needs to be an audible (announced in some way) on cuts for the pilots. [/quote] The lights fix the problem of communicating to the pilots by giving the starter/caller the information visually to relay to the pilots verbally. Simply doing an audio communication via a radio or PA doesn't work because you have no idea if the communication was successful so you don't know if it needs to be repeated. Talkie radios are problematic for the same reasons and communication on them needs to be kept to a minimum so that cuts can be radioed to the lap officials. With the light panels the information is posted until it gets reset at the beginning of the next heat. Many years, input from racers and hundreds of hours have gone into developing this system and it has under gone the fire of several national races as well as last years NATS. The light panels we will have are identical to the NATS system and are interchangeable. This means 1) They can be plugged into any other system using Hank Kauffmann's system, like at the NATS or Speedworld. 2) We can add to the system; i.e., we could change at a later time to a wireless system and have the ability for cut judges to input to the system from their stations at the pylons [current implementation is via RS232 serial cables to keep costs down]. Or we could add on the very large displays that reside physically at pylon 1 in AMA three pole racing. 3) The system can be used for 2 or 3 pole racing as all the cut information is available for either. 4) When and if a transponder system becomes available, our equipment will be compatible. 5) We can sell them to some other club as spare parts if interest in racing wanes. Stan Douglas
Posted on: 6/10/2008 11:30 AM by Author "StanDouglas" in the forum "Club 40"
http://www.rcuniverse.com/forum/fb.asp?m=7602879

RE: X jet scratch build
This has been a great thread. I enjoyed it and will be trying some of your techniques. Just a couple of thoughts, since I'm relatively cheap, I've been using filament strapping tape running span wise around the wing core instead of carbon fiber. I usually use two complete wraps. On a large wing three. It takes some planning as you don't want to cut the tape when you install servos. To further describe it, I run tape top and bottom around the wing from the center-top, around a wing tip, back on the bottom to the other wing tip then back to the start. I do this in two or three places then skin the wing. Seems to be plenty strong enough for Q500's. Originally I saw this used on the "Gremlin" combat wing years ago. On that wing you did the tape and then just covered the foam with low temp covering, no balsa skin. I've also been embedding kevlar strips under the top skins along the aileron hinge lines for gap less hinges. As described in Phil Barnes video "Vacuum Bagging Made Easy". After skinning the wing you cut out a narrow section of the aileron on the bottom skin, then melt the foam from the bottom to the kevlar on the top skin. On the top skin you carefully score the balsa to the kevlar. I use a small thin jewelers file. It makes an extremely strong flexible flutter free hinge that is almost invisible. I located the video you mentioned here and I plan to order it: [link=http://www.airbornemedia.com/store/rv-index.htm]Airborne Media[/link] The Phil Barnes video is here: [link=http://home.paonline.com/hayman/PAGE2.htm]Vacuum Bagging Made Easy[/link] I like Phil's video because of all the other techniques you can pick up beside just making wings. For instance he uses 1.5" square aluminum tubes from Home Depot filled with lead shot for weights. You can make them any length you like, very cool. Ciao, Stan
Posted on: 6/6/2008 11:24 AM by Author "StanDouglas" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=7587627

RE: Next Texas Club 40 race!
Hey that Georgetown Aviation Weather website is great. Thanks for sharing that. I was a little worried about the winds, but from the looks of the forecast it's not a problem. Cloudy too, so little sun to deal with. See ya there, Stan
Posted on: 6/5/2008 6:06 PM by Author "StanDouglas" in the forum "Club 40"
http://www.rcuniverse.com/forum/fb.asp?m=7584874

RE: Computer program for racing heats
I tried to check the link to see if you had anything going there, but the link attempts to load some funky java applet and what with all the viruses I choose to not load it. OK I bit the bullet and allowed the applet to load. The GUI is great. I entered in a test race and it seemed to generate a good matrix. I haven't tested the actual scoring etc. I did enter 16 pilots with two of them having frequency conflicts and all seemed to work well. It would be nice to have a dummy race so one could explore the possibilities of the applet. How do you intend for someone to use this? Most races don't have an internet connection and installing an applet to run stand alone will be a task beyond most RC pylon racers expertise I think. Making it an EXE program would allow others to use it i.e., C++ or Visual Basic. Anyway I like the look and feel, what algorithm is used to generate the matrix? Thanks for making the effort. It would be really nice to have an alternative program to use at races. Good job! Stan D. PS: Contact me about suggestions. I have been working races for many years and have quite a bit of experience with Paul Herman's program as well as having written the timing program on the NMPRA website. There are also some unique requirements for Club 40 style racing involving the generation of the "Mains" after the normal rounds are flown.
Posted on: 4/23/2008 9:27 AM by Author "StanDouglas" in the forum "General Racing Discussion"
http://www.rcuniverse.com/forum/fb.asp?m=7408803

RE: 428 pylon and foam wings
I'm on a budget (poor retired guy). I have been using three strips of carbon fiber tow on the top and four on the bottom. [sm=thumbs_up.gif]But I've been thinking about trying filament strapping tape wrapped around the wing core in a couple of places. I suspect we are over building our wings, but I don't want to be the one to find the lower limit! I used to make a flying wing based on the Gremlin for combat and that's what we used on those wings. I wrapped the tape around in one continuous band and then skinned the wing by bagging it. I never had a wing fail. Anybody try something like that? In my next batch of wings I'm going to make one that way. I'm sure it would be more than adequate for 424 I just don't know about as a 428. Just an idea CF and Kevlar are getting out of hand. I have a Kevlar car cover my wife almost sold at a garage sale last month. It must be worth a couple of thousand now, bought it for $250 several years ago. I too use 1/16 top and bottom and I always have. I've never had a wing fold, but I have had the skin separate due to being too stingy on the epoxy and or not cleaning the core adequately. My wing core templates are set up for 1/16" skins to give me exactly 1-3/16" before covering. SD
Posted on: 4/16/2008 6:27 PM by Author "StanDouglas" in the forum "Q-500 Racing"
http://www.rcuniverse.com/forum/fb.asp?m=7383175

RE: This the plugs for my new Q/500
Great looking molds Kevin. Wish I had the expertise. I'm still cranking out balsa and foam wing Q500's. [quote]No I'm going to make it V Tail. Just a lot easer to layup flat. [/quote] Your V-tail will also have less drag. Especially if the 110 deg angle is at the top of the airframe and doesn't fit in the middle; i.e., on top, forming 3 angles 125/110/125 with the fuse. Verses junctions further down the fuse forming angles of 125/55 and on the other side 55/125. \ / .| Three angles 125/110/125 (the .| represents the fuse. I had to put the period in to force the formating) .| \ / V-tail further down. 125/55/block of wood/55/125. The two 55 degree angles create more drag than the 110. .| .| \|/ V-tail at the bottom, more drag than at the top, 55/55/250 degrees. And then there's __|__ ugh! Very draggy... [:D]
Posted on: 4/16/2008 6:03 PM by Author "StanDouglas" in the forum "Q-500 Racing"
http://www.rcuniverse.com/forum/fb.asp?m=7383101

RE: Incidence Questions
[quote]I would think you want more than "zero lift" at speed, as you need enough lift to keep the airplane flying (unless you're airplanes have no mass to be lifted into the air?). I would also think the "ideal" angle of attack would depend on the given segment of flight (IE..in the straights, turns, ect). [/quote] Gary in the above is absolutely aerodynamically correct. In order to fly straight and level with a 3.75 lb airplane you better have 3.75 lb of lift. If if it's zero you have an RC car at best! The incidence is difficult to calculate because you must factor in the actual airfoil data, the speed, the mass and the low Reynold numbers involved. Most of the faster current airfoils are symmetrical and therefore have a no lift at 0.0 deg. incidence, not like the older MH17 airfoil. When I was messing with Q500 airfoils I used Xfoil for analysis. I never looked too much at Martin's MH series as the NACA 65012 and modifications of it had less drag at Q500 speeds and Reynolds numbers. By the way the MH17 also has a more negative pitching moment that you must over come with the horizontal stab which translates to more drag. But never the less my conclusion was that you needed a smidgen of positive AOA in the wing. If you set up at zero wing and tail you would need to carry a slight amount of up elevator in order to force the AOA for the lift required. One might argue what's the difference in carrying a little up or having incidence in the wing or negative incidence in the tail? I would guess not much except maybe cleaner airflow over the tail if the elevators not deflected all the time. Plus if you force the entire airframe to move with the elevator you're also changing the thrust line of the engine as well as the wing. It would be interesting to find the actual AOA of a Q500 pulling through a hard turn at pylon one. It would be tough because of the rate of change in relative air flow. It obviously doesn't go past around 12 deg. or it would snap when the wing stalled. But it sounds like you are well into solving your issues. By the way, from the photos above it's a great looking airplane. SD
Posted on: 4/16/2008 5:36 PM by Author "StanDouglas" in the forum "Q-500 Racing"
http://www.rcuniverse.com/forum/fb.asp?m=7382957

RE: Incidence Questions
Every once in a while I build one that has pitch problems even though I use templates, a router and cut the wings from the same templates and a Feathercut system. When it has happened I simply loosen the wing bolts and place 1/32" shims under the front bolts (given I want to give it more positive incidence) tighten the bolts and fly. If it''s better, but not great, land and add another shim and so on until it''s right. Of course if its getting worse we may need shims under the trailing edge bolts. Once I''m happy, I re-pot the wing saddle with epoxy and filler with the shims in place. The shims become part of the saddle. Your going to find that getting the incidence to within .04 deg is a little precise. And anyway the actual incidence required will be slightly different depending on how well you cut the wing core; wire lag, sanding the skin, incidence of the tail and all the rest. Depending on all the variables you might actually need to alter the engine thrust line as well. Usually Q500''s work well with 0 engine incidence. But some actually require a different set up. You can do all the usual things like for a pattern plane. It''s actually an art form, so it may help to get a local artist help out! Ciao
Posted on: 4/15/2008 11:35 AM by Author "StanDouglas" in the forum "Q-500 Racing"
http://www.rcuniverse.com/forum/fb.asp?m=7376660

RE: Austin, TX Season Opener - April 5, 2008
Our thanks to Power Master who supplied the fuel and to Round Rock Hobbies who supplied awards: Click on the link below for the complete results: [link=http://www.nmpra.org/event_results/ARCA-April-2008.html]ARCA Season Opener[/link] Chuck Esh supplied lazer cut coasters as awards for all the classes, the race director and fast time. Super momentos! Enjoy Stan
Posted on: 4/8/2008 10:26 AM by Author "StanDouglas" in the forum "Club 40"
http://www.rcuniverse.com/forum/fb.asp?m=7340839

RE: Viper Pitch issue
About the Viper, has anyone written about their trim experience? That is, with a Viper out of the box, after trimming for hands off, in knife edge with neutral controls does it tuck to the wheels, hold it's line or nose to the wing? When you pull vertical and cut the throttle does it pull either to the left or right or towards or away from the wheels. From straight and level and you chop the throttle does it continue in a straight line? In a 90 degree knife edge, pulling hard up does it pitch towards the ground or to the sky? The really good pilots actually don't just have better thumbs than most of us do they don't work as hard to fly the course because they have set up their airplanes to fly with a minimum of thumb input. Stan
Posted on: 3/17/2008 11:01 AM by Author "StanDouglas" in the forum "Q-500 Racing"
http://www.rcuniverse.com/forum/fb.asp?m=7238066

RE: Viper Pitch issue
Hunting is a somewhat common problem with fast symmetric airfoils. Hunting; The Q500 settles so you feed a little up and it starts to climb so you feed a little down and it starts to settle again and so on. Very unsettling if your actually trying to race with this behavior! Another pitch issue with these airfoils can be changes in pitch from throttle changes; i.e., cut the throttle to land and it either balloons or starts sinking or vise versa. I at one time built a batch of somewhere around 15 Q500's for various people and they were all made from fuse templates and foam wings cut from the same foam cutter jig. The CG, incidence and etc were all set up the same and out of all of those one had a hunting problem. In my case, since the tail was an integral part of the fuse (linkages inside the fuse out of the air stream) the final solution (after fiddling with the CG and much consulting) was to shim the leading edge of the wing for a positive AOL. I still have that particular Q500 and the next time I'm setting up some V-tails I'll check what incidence I wound up with. At the time I was told one of the things that can cause this problem is too sharp of a wing leading edge. This can also cause snapping in high AOL situations. The hunting apparently has something to do with large changes in the airflow over the wing with slight changes in AOL. When you think about it, if you set up a Q500 absolutely perfect with every thing a 0 incidence; i.e., 0-0-0, you must carry some slight up elevator in order to give the symmetrical airfoil to develop lift of 3.5 lbs. Otherwise the airplane will not fly. Symmetrical wing at zero incidence has zero lift. I once calculated the AOL for a NACA 65-0012 on a Q500 flying at 150MPH and generating 3.5 lbs of lift. It actually came out to less than 1/2 degree of positive AOL as I recall. I did try building that into one of my planes, but it wasn't worth messing around with. At 1/2 degree I had to shim it the other way. I don't know this for a fact, but my gut feel is that setting the entire V-tail by shimming it would create less drag than carrying up elevator. Although the whole tail section in the area of the linkages and junctions at the fuse of the Viper are terribly draggy anyway. It would be interesting to me to know what incidence, in degrees, you all are actually winding up with when you shim the V-tail. By the way I arrived at getting my hunter to stop hunting by progressively raising the wing leading edge by placing 1/32" with plywood shims under the front wing bolts and flying. Once I had the incidence that worked I made up a slurry of epoxy and filler on the fuse wing saddle putting Seran Wrap on the wing and bolting it down with the shims until it cured. On a Viper you would probably need to remove any covering in the saddle area so the epoxy would bond with the balsa. There is obviously a difference between carrying some up trim in the elevator and shimming the entire tail or wing. Other wise one could simply dial in some up elevator and be done with it. Maybe someone with a better understanding of the complexities airfoils and airflows can enlighten us. Even though you build Q500's using the same templates etc. there will be variations from one to another due to wire lag on the foam cutter, balsa variations, differences in sanding the sheeting and a lot of other things. The most consistent you can get is to make composites using molds. Stan
Posted on: 3/17/2008 10:36 AM by Author "StanDouglas" in the forum "Q-500 Racing"
http://www.rcuniverse.com/forum/fb.asp?m=7237932

Different kind of plug?
I'm just about out of K&B 1L plugs. Anyone know a good source for K&B 1L's? I would like to get a whole card of them. How about Thunderbolt plugs? I hear they make an excellent 4-stroke plug #115490, but I can't locate a dealer. Ciao Stan D.
Posted on: 3/12/2008 5:27 PM by Author "StanDouglas" in the forum "Q-500 Racing"
http://www.rcuniverse.com/forum/fb.asp?m=7214587

RE: C-40
Chris, I'm interested in what problem you are having completing your NMPRA registration. I show you as being registered, but not activated. Your user name is ChrisAttebery. Did you not receive the Email to complete the registration? I went ahead and made the account "Active" so you should be able to access the forum. But I would appreciate it if you would let me know what the problem you experienced with completing it. Regards, Stan Douglas NMPRA webmaster
Posted on: 2/22/2008 10:03 AM by Author "StanDouglas" in the forum "Club 40"
http://www.rcuniverse.com/forum/fb.asp?m=7117861

RE: OS MAX .10 FP tricked out
I just stumbled on this thread and it's been a while since anyone posted here, but haven't you tried boring out the carb? I don't know how the OS .10 compares to the OS FP .20 but years ago there was a writeup on the .20 by Mark McCool: -------------------------------------------------------------------------------------------------------- After disassembling the carb and noting the needle valve position in the venturi, The next step requires a ¼" carbide drill bit for the .20 FP carburetor and a 3/16" carbide drill bit for the .15 FP carb respectively. Clamp the carburetor body into the drill press (or mill) fixture upright and 90 degrees to the table. With plenty of cutting oil and the sharp drill bit at LOW speed, drill the venturi completely through from the top to the bottom of the carb body (GO SLOW and use plenty of oil). Clean and debur all edges across which the bit has passed with a half-round needle file and/or emery cloth. Run the carburetor retaining screws that were removed in disassembly in and out of their holes in the bottom of the carb body to rethread the inside of the larger opening. Remove all metal flakes and thoroughly clean the carburetor body with brake cleaner then lube it with WD-40. Test fit the carburetor into the front case, adjust the carb accordingly (if necessary), clean it, and remove it. The carburetor barrel is made from a strange grade of tempered steel and requires special treatment because the metals tend to mushroom and flake (this process is not for the faint-hearted which is why I suggest a machine shop). For those well-equipped brave souls…With torch and vise-grips, heat the carburetor barrel red-hot to take the temper out of the material. After it is slowly cooled, clamp the carburetor barrel into the drill press (or mill) fixture with the throat upright and 90 degrees to the table. IMPORTANT—The next step requires a ¼" carbide ream for the .20 FP carburetor and the 3/16" carbide ream for the .15 FP carb respectively! With plenty of cutting oil and the sharp carbide REAM at HIGH speed, ream the throat HALF WAY through from the top. Turn the carb barrel over in the fixture and repeat the process from the bottom, this time reaming all the way through. (REMEMBER--GO SLOW and use plenty of oil). Clean and debur all edges across which the ream has passed with a half-round needle file and/or emery cloth. Reinstall the plastic throttle arm and retaining screwinto the end of the carburetor barrel. -------------------------------------------------------------- Next there was a tuning method to move the needle assembly as far out of the venturi as possible to allow for more flow through it. -------------------------------------------------------------- With the exception of the needle assembly, reassemble the carburetor and recheck, adjust, and clean it for a snug fit and smooth operation. Return the low-speed idle screw to its original setting. Assuming you are ready to run the engine, reinstall the needle valve so that the outlet is only half as deep into the venturi. The purpose of this exercise is to maximize the airflow through the venturi by removing all obstructions. Reinstall the carburetor onto the front case. The carburetor is finished! Now its time to tweak your .20 FP! If you tach the engine now, you’ll be very pleased with the results. Test the idle reliability and if not satisfactory, adjust the low-speed screw accordingly. Once idle reliability is achieved and high speed is satisfactory, turn the engine off, loosen the needle assembly and back it out, splitting the difference between where the needle outlet was in the venturi and the edge of the venturi. Tighten the needle assembly, run the engine, and repeat the tweaking of adjusting the high-speed needle, testing and adjusting the low-speed for reliable idle. The farther out you back the needle outlet, there seems to be a tradeoff with reliable idle, so the purpose of this exercise is to find the optimum point so you achieve maximum RPM at high speed without sacrificing satisfactory idle. -------------------------------------------------------------- Don't know if any of this applies to what your doing or not. Regards, Stan Douglas
Posted on: 2/3/2008 3:21 PM by Author "StanDouglas" in the forum ""1/2 A" & "1/8 A" airplanes"
http://www.rcuniverse.com/forum/fb.asp?m=7018295

RE: Matrix / Scoring
I have everything in a box and working. I had a slight problem in that I broke an land on the board and it took a while to find it. In the process I have gained a better understanding of how the board actually works. There are some commons on the board. There are 4 of them for the digital inputs. I am ignoring the analog inputs. Each digital input is paired through diodes. There are actually 18 digital inputs on the board. #17 sets the mode and #18 is what I'm calling a spare as it isn't used (no button to it). 1, 11, 12, 14 are common, as are 2, spare, mode, 15 and 3, 4, 10, 13, 16 and 5, 6, 7, 8, 9. These lines are given a pulse depending on the diode pair of which there ar a total of 19 diode pairs. I haven't put a scope on the board yet. What this all means is that there's an easier way to wire this thing up. Attached is a shot of my box with out labels. Each button is wired in parallel with a phono jack to provide external push buttons. I have buttons for laps, the lower set, cuts at pylon 1 the upper set and cuts for pylon 2. There is also a row of phono jacks with out buttons pylon 3 cuts should I need it for 3 pole racing. Since there is little interest here on this forum, I'll move this project to the NMPRA website for all future posts as well as the simplified box wiring. SD
Posted on: 12/4/2007 1:31 PM by Author "StanDouglas" in the forum "General Racing Discussion"
http://www.rcuniverse.com/forum/fb.asp?m=6712662