RE: Contra Rotating Propeller Drive for f3a 2m Pattern Planes
Hi Arch, I cut the nose off of a Spark Dynamic, I’m not sure if that would be required for the Spark Evo. The spinner on the Dynamic is 64mm but the contra is 82mm, if the spinner for the Evo is around 82mm then I doubt Robert would want to remove a portion of the nose. Robert could build a new rudder, I’ve done several sets of built-up rudder parts by hand but they did not have a flare at the trailing edge just a thickened trailing edge. I’ve attached a plan and several pictures of what I did for a built up Xigris rudder, since it was all straight cuts it was easy to get the rudder parts and jigs at the same time. Dave Snow
Posted on: 8/2/2012 12:59 PM by Author "Dsnow" in the forum "Electric Pattern Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=11178762

RE: Contra Rotating Propeller Drive for f3a 2m Pattern Planes
Hi Vincent, the wing Brenner has is not the elliptical wing but a modified Spark Dynamic wing, it looks hard to build but with the jigs and interlocking spars/ribs it’s not too difficult to build, if you've built a foam wing you can build this wing. I've never sent a built wing/stab international but if I assume a box 35"x20"x6" FedEx is $344 for 3 days, USPS Global Express (3 days) is $190 and Express Mail® International (3 to 5 days) is $75. With any of these shipping options I am concerned about the wings being damaged and unusable after you receive them that's why I think the kits would be a better option for you, do you know someone that can build for you in France? If you have any questions about the wings or kits please email me. Dave Snow
Posted on: 4/9/2012 12:08 PM by Author "Dsnow" in the forum "Electric Pattern Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=11034722

RE: Contra Rotating Propeller Drive for f3a 2m Pattern Planes
Hi Vincent, fitting the parts to the Integral is no problem, shipping is. I built the wing and stab panels Brenner is flying and basically hand delivered the parts to him so no shipping was involved, but to France built components would be very costly. I do have kits for the wings and stabs that I’ve sent internationally without too many problems. Here is a build thread showing how they go together, http://www.rcuniverse.com/forum/m_10841584/tm.htm . The wing you will save the most weight, typical weight ready to fly 14 oz but with very good wood – 3/32� wing sheeting 14 to 15 grams each – we have built several Spark Evo wings at 12 oz. Dave Snow
Posted on: 4/7/2012 2:33 PM by Author "Dsnow" in the forum "Electric Pattern Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=11032137

RE: Contra Rotating Propeller Drive for f3a 2m Pattern Planes
Hi Dick, was the rudder throw taken at the top or bottom of the rudder? Without the rudder chord I cannot calculate the deflection. Thanks, Dave Snow
Posted on: 3/20/2012 8:01 PM by Author "Dsnow" in the forum "Electric Pattern Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=11009044

RE: Contra Rotating Propeller Drive for f3a 2m Pattern Planes
Hi Peter, so far the rudder throws are grouped in three ranges, less than 5 deg, between 10 and 15 deg and more than 25 deg. From the test report I post earlier and their conclusions I believe the best initial rudder throw should be around 13 deg or maybe equal to the elevator throw for the plane, I did not compare the elevator and rudder throws but I think most elevator throws are in the 10 to 13 deg range. I’m still waiting for a few pilots to help out but I did ask one of the high rudder throw fliers to try reducing his throw, he went from 25 deg to 14 deg, and he said it worked great. The less than 5 deg group was two biplanes, so if anyone is planning on using a biplane this would be a good starting point. Also from the test report we could use slightly weaker rudder servos since it takes less force to move the rudder but it should have great centering and zero backlash and no play in the linkage. This would help reduce the chances of the plane from initiating the yaw instability with small yaw angles. One other change that we could make, I only have one data point on this, is to reduce the chord of the rudder to make it smaller. From the information posted here over the last few months I think most of the yaw instability issues we have seen last year could be self-induced and not so much the design of the plane if we are using too large of rudder throw and have too much play/poor centering of the rudder. I hope several of the high rudder throw guys would try the reduced throw and give us a report if the yaw instability issues are solved or reduced any. Hi Greg, I think almost any current design will work very well with the contra. Dave Snow
Posted on: 3/20/2012 6:19 AM by Author "Dsnow" in the forum "Electric Pattern Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=11008123

RE: Contra Rotating Propeller Drive for f3a 2m Pattern Planes
Contra fliers, if you could help me please I’m looking for the rudder throw that you are using for your normal flying condition in either degrees or deflection (in. or mm ok) and the width of the rudder where the deflection is taken. Please pm or email me through RCU, I’ve contacted a few fliers directly and thanks for the info. I was just wondering after a year of flying have most fliers migrated to similar deflections and what that is; it could be helpful for new fliers with their initial setups or it may give existing fliers an idea what others are using. Hopefully the numbers will be meaningful. Thanks, David Snow
Posted on: 3/10/2012 12:47 PM by Author "Dsnow" in the forum "Electric Pattern Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10994378

RE: Contra Rotating Propeller Drive for f3a 2m Pattern Planes
After reading what Dean and Tony have said about the destabilizing effects of the prop I was curious about the aerodynamics behind this effect so I emailed Dean for some help. Several emails were sent back and forth, thanks Dean for being patient with me, with his reference material and I found some reports and articles on the net that helped to make things more clear. Below is some of the info I found helpful: several articles by George Hicks and two reports made in the 1940’s. George’s articles can be found here: http://jrradios.com/Articles/Article.aspx?ArticleID=1101&Page=2 One of the reports can be found here: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930093328_1993093328.pdf And the other report here: http://naca.central.cranfield.ac.uk/reports/1945/naca-report-820.pdf Both reports are lengthy, the first one mostly graphs and the second one very technical, but below are the conclusions from the first report listed. Dave Snow [i][b]Conclusions[/b] The results presented lead to the following conclusions with regard to the yaw characteristics of the single-engine airplane model with a single-rotating and a dual-rotating propeller: 1/.. The most noticeable differences shown were the large directional trim changes with the singe-rotating propeller and the negligible trim changes with the dual-rotating propeller. With the single rotation-rotating propeller, large rudder deflections and forces were required to trim (Cn = O) at zero yaw in the low-speed, high-thrust conditions, whereas with dual rotation, only sma11 deflections and forces were required. 2/.. The model with dual-rotating propellers was directionally stable with rudder fixed throughout the trim range for all conditions. Beyond the trim range, reversals of the yawing moment curves occurred in the approach condition; these reversals might produce instability if the rudder range were increased sufficiently. With single rotation, rudder fixed, the model was unstable at large angles of left yaw in the approach (flaps-down) condition and exhibited a tendency to be unstable in the climb (flaps-up) condition. The instability in the approach condition also occurred with rudder free and in a manner termed “rudder lock�; that is, as the increasingly unstable yawing moment yaws the airplane to the left, the hinge moment forces the rudder continually harder against the stop. 3/.. Although of secondary importance for the model tested, a greater degree of rudder-fixed stability was generally shown with single-rotation than with dual-rotation at small to moderate angles of yaw. At zero yaw, the slopes of the yawing-moment curves were about 15 percent more stable with single rotation in the approach, climb, and high-speed conditions than with dual rotation. 4/.. The rudder-control effectiveness d(psi)/d(sigma) in the high-speed condition was about 10 percent greater with dual-rotation than with single-rotation. In the climb condition, angles of yaw maintained by +/-20 deg of rudder were +/- 21 deg with dual-rotation, and 2 deg and 23deg with single-rotation. In the approach condition, the angles of yaw were +/-11 deg with dual-rotation, and 2 deg and -23 deg with single-rotation. 5/.. The rudder-control forces per degree of yaw were two to three times as great for single rotation as for dual rotation in the low-speed high-thrust conditions.[/i]
Posted on: 3/4/2012 8:37 PM by Author "Dsnow" in the forum "Electric Pattern Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10986781

RE: Contra Rotating Propeller Drive for f3a 2m Pattern Planes
Any of the mounting systems work well, I’ve used all three types of mounts but prefer the Hyde mount, my second choice is the carbon plate with Budd isolators and lastly is the lord mounts. Dave Snow
Posted on: 2/23/2012 8:29 PM by Author "Dsnow" in the forum "Electric Pattern Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10973248

RE: Contra Rotating Propeller Drive for f3a 2m Pattern Planes
Hi, I would not recommend hanging the Neu motor and contra drive; the components are very expensive, the weight of the motor and drive combined will mask any gyroscopic effects of the drive when operating and you would be adding a third unaccounted gyro – the Neu motor – into the test that’s not present in the test setup in the previous post. From the research and tests that I’ve done I see no reason to make any modifications to the test setup as was suggested, cancelation of the gyroscopic forces and the elimination of any gyroscopic stability effects is clearly seen with the setup as is. As Tony mentioned earlier the test setup does not represent the contra unit as installed in the plane but it should be an accurate representation of the contra drive itself. The setup and drive have two rotating masses with their axis of rotation parallel to each other. One test to see if the support point effects the gyroscopic effects is by running the setup with one motor turning and supported behind the rotating mass and then run both motors turning in the same direction with the support between the two motors; both test runs had very similar results as described in my earlier post. Another example is the video I posted back in January, here’s the YouTube link http://www.youtube.com/watch?v=bzbVwiIeM0M , that shows two gyros side by side, their results are similar to the tests that where described above when they are run in the same direction and opposite directions. From these observations the location of the axis point or the position of the gyros does not have an influence on the gyroscopic effects but the shafts of the rotating masses need to be aligned to see the cancelation of the gyroscopic forces when the masses are rotated in opposite directions. I know that there have been tests conducted with the contra unit in the plane and it appears that the gyroscopic effects are removed except for gyroscopic stability, I believe these test are mostly flawed. There are several forces that could easily be mistaken for gyroscopic stability. When the contra drive is operating there is a massive amount of air flow over the fuse and flying surfaces stabilizing the plane. Also there is the mass of the plane that must be rotated and this will be adding a force to resist rotation when initiating the movement. My test setup has no aerodynamic forces similar to the plane and the setup is balanced to eliminate the effects that the weight will cause. One item that could be adding gyroscopic stability to the test with the plane is the motor that’s driving the contra and this could be what is felt by the tester. I do not know what this force is but it’s not addressed in my test setup since I was more interested in the contra drive itself. I’m also making an assumption, correctly or incorrectly, that this force is relatively small compared to the gyro effects of the props in the contra system. I know that there will be disagreements with much of what is described in the earlier post and this one and I wait for any comments but until some new information is made available I believe this to be accurate. Dave Snow
Posted on: 2/18/2012 7:55 PM by Author "Dsnow" in the forum "Electric Pattern Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10965301

RE: Contra Rotating Propeller Drive for f3a 2m Pattern Planes
Hi Brenner, back in January there was discussion about the contra system and gyroscopic stability and I decided to make a test rig up to avoid all the math and eliminate any aerodynamic forces. Finally the parts for the test setup came this week and attached are several pictures of the setup. I received two D4023-850 outrunner motors, two 6460 Hobbyking SS Series 25-30A esc’s, one ZIPPY Flightmax 1000mAh 3S1P 15C battery and one 17143 Simple Servo Tester all from Hobby King. The motors have pedestals that are attached back to back and then the esc’s and battery are strapped together. The motors weigh about 105 grams, they are rated at 850kv and are 41mm in diameter, with the speed and mass of the motors the gyroscopic effects can be easily seen but still safe to hold by hand. After trying several arrangements for testing it seemed best to suspend the motors from the six motor/controller wires, this provides a good mix of flexibility and stiffness. Following are my observations with the motors off, motors on spinning in the same direction and motors on spinning in the opposite direction. When the motors are off, hung from the wires vertically and a twisting motion is made at the top of the wires the motors and wires move as a single unit with no resistance to the twist. If this twisting motion is increased to a faster back and forth twists the motors twists back and forth faster and no twist is seen in the wires. When the motors are swung from the wires along the axis of the motor shafts the motors swing with no twisting or rotation of the motors – the motors follow the arc of the swing. When the motors are on and spinning in the same direction, the same effects are seen when only one motor is on, hung from the wires vertically and a slow twisting motion is made at the top of the wires the motors resist this motion. The wires can be seen to twist and the shaft of the motors make a motion following an arc mostly in a vertical direction. If this twisting motion is increased to a faster back and forth twists the motors remain stationary and the wires twist. When the motors are swung from the wires along the axis of the motor shafts the motors twist the wires and the shafts follow an arcing motion mostly to the left and right. When the motors are on and spinning in opposite directions the test rig reacted to all the motions of the wire as if the motors were off, I felt and saw no resting force to stabilize the system. It appears to me that all forces are cancelled and there is no gyroscopic stability present when the motors are spinning in opposite directions. This is the most basic setup that I can think of with the twisting motion simulating yawing of the plane while the swinging of the motors in an arc should simulate pitching of the plane. If anyone can think of modifications to the tests please let me know. I plan to have lunch tomorrow with the pattern gang in this area and I will bring the test rig with me so they can play with it, maybe if one of them has a video phone we can get something posted. A short video would be much better than me trying to explain what I saw and felt. Dave Snow
Posted on: 2/17/2012 1:18 PM by Author "Dsnow" in the forum "Electric Pattern Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10963484

RE: New Krill Spark Evo I- Build Thread.....
Hi Rune, I have carbon canopy wt = 183g and plastic canopy wt = 220g for Spark Dynamics, the carbon canopy is from the first batch of planes so Krill may have improved on fabrication since then. Dave
Posted on: 1/15/2012 5:14 PM by Author "Dsnow" in the forum "Electric Pattern Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10910581

RE: Contra Rotating Propeller Drive for f3a 2m Pattern Planes
Hi Greg, Chip had a nice report in post #338 on page 14 and flew the Visa with and without the rudder split, must be nice to have that option. Dave
Posted on: 1/10/2012 3:32 PM by Author "Dsnow" in the forum "Electric Pattern Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10902332

RE: Builtup stabs for Integral
Hi AC, the wing kit is almost an identical copy to an original Passport wing but with increased dihedral and no wing tips, your existing ones should fit. I only have one stab kit and it's based off the Spark Dynamic, the stab will not save too much weight from the orginal. If you're looking to save some weight the wing kit would be the way to go if your panels are over about 16 oz each ready to fly, new ones with good wood should weigh around 13 oz each ready to fly. The kits are relatively easy to assemble. Dave
Posted on: 1/3/2012 11:50 AM by Author "Dsnow" in the forum "Electric Pattern Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10889698

RE: Builtup stabs for Integral
Hi Gerrie, I also did a build thread http://www.rcuniverse.com/forum/m_10841584/tm.htm that shows how I've been building both a stab and a wing kit. The stab kit can be built with anhedral or flat, I have several wing kits: Spark Dynamic AJ, Spark Evo AJ, PassPort/Visa, Onas and the wing on the build thread that has not flown yet. You can email mail me at rcparts@att.net and I will try and answer any questions you may have. Do you think there is an interest in a Integral replacement wing kit? Are people still buying this model? I could do the Integral wing or the Xigris if there is interest in wing kits, let me know. Dave Snow
Posted on: 1/3/2012 5:58 AM by Author "Dsnow" in the forum "Electric Pattern Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10889171

RE: Building a built-up pattern stab and wing
I’ve mentioned paper sockets before and here are some pictures of a paper socket being made for the next wing I'm starting. I use a coated paper but any paper should be ok. The mfg socket in the last picture is the same length as the paper sockets but for a 7/8" dia tube, the paper socket being made is for 25mm wing tube. Dave
Posted on: 12/31/2011 8:03 AM by Author "Dsnow" in the forum "RC Pattern Flying"
http://www.rcuniverse.com/forum/fb.asp?m=10884404

RE: Contra Rotating Propeller Drive for f3a 2m Pattern Planes
Hi Jim/Brian, I’m going to keep this short since I am not up on all the math but here’s a video with two gyros in a rigid frame showing the effects when spinning in same direction and then in opposite directions. http://www.youtube.com/watch?v=bzbVwiIeM0M What do you think? This was the best example I could find on counter, not contra, rotating gyros and shows the forces canceling out. Does the gyro alignment make any difference? At this time I do not think so since it's in a closed system, it would be great if someone could find another video showing different results. Question: if having two contra rotating gyros cancel out the precession but maintains or adds gyroscopic stability why aren't some mechanical gyros built this way? One gyroscope that has been left out of the talk for the contra system is the motor itself. Is the motor gyroscopic effects small or large, I do not know but maybe someone can do the math and then compare these forces to the gyroscopic forces from a single prop. I would hope that the motor forces are small and the prop is large because then with the use of the contra gyroscopic forces would be reduced. Assuming the gyroscopic force of the props is relatively large, compared to the motor, and are canceled this loss of gyroscopic stability could explain why the elevator and rudder are more sensitive. This should be good news, now this is one more force/load out of the system that the plane does not have to be designed to fight but at the potential loss of some stability. Any thoughts? Dave
Posted on: 12/29/2011 1:13 PM by Author "Dsnow" in the forum "Electric Pattern Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10881573

RE: Contra Rotating Propeller Drive for f3a 2m Pattern Planes
Hi Malcolm, would it be easier to get the Blade CX helicopter than some cheap gyros; it already has contra rotating blades. I’ve not flown one but from what I’ve heard they are so stable anyone can fly them. http://www.blade-cp-pro.com/blade-cx.htm Hi Tony, I think you've stated several times that the propeller causes yaw instability with the single prop setup when in front of the cg and by adding a second prop the instability is increased, am I stating your thoughts correctly? I found some info here http://history.nasa.gov/SP-367/chapt9.htm#f143 that seems to indicate that the contra prop system is a solution to this issue. This may be due to the elimination of “sidewash�, what do you think? “A tractor propeller of a typical airplane is a destabilizing influence on the directional stability, and it also imparts a rotational velocity to the slipstream. As shown in figure 143 it produces a sidewash angle at the tail that reduces the static stability effectiveness of the tail. This effect can be very pronounced in aircraft with large engines. The Grumman F8F Bearcat, a carrier plane, would require a certain degree of rudder offset by the pilot to counteract the yaw induced by the sidewash during high powered take-offs. Contrarotating propellers are a solution to this problem.� Thanks, Dave
Posted on: 12/27/2011 12:44 PM by Author "Dsnow" in the forum "Electric Pattern Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10878316

RE: Contra Rotating Propeller Drive for f3a 2m Pattern Planes
Hi Everette, thanks for the kind words but I have no desire to design a plane and without that it would be pointless to start. I do find the talk interesting about what everyone thinks is needed for the contra to work and what causes the instability. As mentioned much earlier in the thread by someone I’m in the camp of thought about the plane being preloaded – torque and prop swill counteracted by right thrust and the rudder. With the contra essentially removing both these items the back of the plane does not know what to do until enough airspeed is gained to hold the tail in the proper location. I think the thickened rudder trailing edge is adding this preload force back into the system. With a rudder trailing edge thicker than the hinge line there can be equal and opposite forces on each side of the rudder by unmasking or letting the rudder “see� the airflow at low speeds. There may other or better ways to add the preload force back into the system but this seems to be the easiest to do. Personally I do not like the method of adding triangle stock or aileron stock to the rudder trailing edge to make it thicker. I believe that this method can cause an excessive amount of drag and may also cause a pitching moment into the system. With the triangles there are two locations that are causing drag, the trailing edge of the rudder and the leading edge of the applied triangle. I think the better solution is to make the rudder flat/straight from the rudder hinge line to the trailing edge, this removes one of the causes of drag with the thickened trailing edge. I agree with others that the fuse shape has a major role in how these loads/forces are resolved; more fuse area forward/larger or blunter canopy = slower overall plane speed and more preload required, less fuse area forward/sleeker canopy/larger fin = faster overall plane speed and less preload required. After the NATS I spent most of my time and contests flying a Wind S Pro with the contra and the first thing I noticed was how much faster the plane was than the Spark with the same prop and gearset. In stock configuration the Wind and I were not getting along but I had a chance to fly the fuse with two other wings and I was surprised the overall speed of the plane did not drastically change, this makes me think that the fuse has a larger role in plane speed than the wing size/shape/airfoil that is typically used for the current pattern designs. At the end of last year we did some testing to find some solution for the instability issue, a portion of the email is attached here and some may find it humorous or interesting. Dave Snow
Posted on: 12/25/2011 12:46 PM by Author "Dsnow" in the forum "Electric Pattern Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10875776

RE: Building a built-up pattern stab and wing
Thanks guys, the bad news is my wing panels are 3 grams different - going to need more stickers on one side. Dave
Posted on: 12/14/2011 4:55 PM by Author "Dsnow" in the forum "RC Pattern Flying"
http://www.rcuniverse.com/forum/fb.asp?m=10859803

RE: Building a built-up pattern stab and wing
My part of the build is finished, sorry Mike I could not get you panels as lite as mine and I messed up somewhere in matching weights. Here is the finished wing on the messy table and the finished panels weights. Dave
Posted on: 12/14/2011 1:41 PM by Author "Dsnow" in the forum "RC Pattern Flying"
http://www.rcuniverse.com/forum/fb.asp?m=10859490

RE: Building a built-up pattern stab and wing
More
Posted on: 12/14/2011 1:38 PM by Author "Dsnow" in the forum "RC Pattern Flying"
http://www.rcuniverse.com/forum/fb.asp?m=10859482

RE: Building a built-up pattern stab and wing
Hinging, shaping leading edge of aileron, cutting aileron servo box open, installing hard point. Dave
Posted on: 12/14/2011 1:36 PM by Author "Dsnow" in the forum "RC Pattern Flying"
http://www.rcuniverse.com/forum/fb.asp?m=10859475

RE: Contra Rotating Propeller Drive for f3a 2m Pattern Planes
Looks like the pins on the planet gear carrier are much larger too, that should prevent any wobble of the planet gears. Looks great. Did the planet gears get any thicker from the new bearings? Dave
Posted on: 12/13/2011 8:13 PM by Author "Dsnow" in the forum "Electric Pattern Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10858509

RE: Building a built-up pattern stab and wing
More
Posted on: 12/13/2011 8:05 PM by Author "Dsnow" in the forum "RC Pattern Flying"
http://www.rcuniverse.com/forum/fb.asp?m=10858500

RE: Building a built-up pattern stab and wing
Yes, a small messy shop. Tip rough shape, rounding leading edge and tip, cutting aileron off / sanding and gluing aileron leading edge. Dave
Posted on: 12/13/2011 8:03 PM by Author "Dsnow" in the forum "RC Pattern Flying"
http://www.rcuniverse.com/forum/fb.asp?m=10858499

RE: Building a built-up pattern stab and wing
I wish you luck Ken, it should be a blast to fly when done. Thanks Dean, I think some of the fliers used a similar or that method around here in the early 90's, it worked really well. The nice thing about the laser cut parts is the repeatability and for lazy people like me no cutting of ribs or trying to cut foam. Dave
Posted on: 12/13/2011 12:29 PM by Author "Dsnow" in the forum "RC Pattern Flying"
http://www.rcuniverse.com/forum/fb.asp?m=10857724

RE: Building a built-up pattern stab and wing
Leading edge rough shape, centerline and tip blocks glued on. Dave
Posted on: 12/13/2011 8:48 AM by Author "Dsnow" in the forum "RC Pattern Flying"
http://www.rcuniverse.com/forum/fb.asp?m=10857418

RE: Building a built-up pattern stab and wing
Mike, it should be a good plane after it gets all trimmed out. I had other things going today but was able to sand the leading edge and tip, match the panels and glue the leading edge balsa on. Dave
Posted on: 12/12/2011 8:04 PM by Author "Dsnow" in the forum "RC Pattern Flying"
http://www.rcuniverse.com/forum/fb.asp?m=10856743

RE: Building a built-up pattern stab and wing
More
Posted on: 12/11/2011 7:15 PM by Author "Dsnow" in the forum "RC Pattern Flying"
http://www.rcuniverse.com/forum/fb.asp?m=10855001

RE: Building a built-up pattern stab and wing
Both bottom skins glued on, trimming leading edge, installing aileron hinge doublers, installing servo box, installing solid balsa blocking for aileron stud and applying glue to attach top skin. Dave
Posted on: 12/11/2011 7:14 PM by Author "Dsnow" in the forum "RC Pattern Flying"
http://www.rcuniverse.com/forum/fb.asp?m=10854998