RE: Nitro proof paint
I contacted WarBirdColors twice recently inquiring about ordering some paint, and I never received an answer. The website is sill on, but mentions supply problems. Has anybody ordered successfully from WBC in the recent past? If so, how? Thank you
Posted on: 9/9/2012 11:05 AM by Author "ululi1970" in the forum "RC Warbirds and Warplanes"
http://www.rcuniverse.com/forum/fb.asp?m=11222827

RE: How many wing bolts?
It looks like that jury is split between one and two. I can see good points made for either one. Safety in the air vs. limiting damage on the ground... For the record, it is a Pica Kit, NOT an ARF. The wing has two dowels (well, actually horizontal plywood tabs that fit into slots in the fuse) and it is a single piece. I will start replacing the bolts on my other planes regularly, just to be safe... Alberto
Posted on: 9/5/2012 3:50 AM by Author "ululi1970" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11218040

RE: How many wing bolts?
I agree that the bolts are meant to break on impact to limit the damage to the wing/fuse. In fact, I saw it in action not too long ago. I will go with the design. Thank you Alberto
Posted on: 9/4/2012 7:44 AM by Author "ululi1970" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11216866

How many wing bolts?
I am finishing a .60 warbird. The plan calls for just one 1/4-20 nylon wing bolt and I am wondering if this is enough. Or Should I use two bolts, maybe smaller (say #10)? Thank you Alberto
Posted on: 9/4/2012 6:34 AM by Author "ululi1970" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11216788

RE: HOw much paint do I need?
After looking at his web site, and reading the glowing endorsement by Tom Pierce, I'll give WarBird Paint a try. Than you for your help. Alberto
Posted on: 9/4/2012 4:49 AM by Author "ululi1970" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11216700

RE: HOw much paint do I need?
[quote]ORIGINAL: Platinum Go have a look at :http://web2.murraystate.edu/andy.batts/ps/powersupply.htm [/quote] Not sure that is the correct webpage... Alberto
Posted on: 8/29/2012 5:45 PM by Author "ululi1970" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11210875

RE: HOw much paint do I need?
Thank you. I fly with the FLying Tigers of Jordan Lake, off Jordan Lake, of course. Alberto
Posted on: 8/29/2012 12:23 PM by Author "ululi1970" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11210512

RE: What is the
[quote]ORIGINAL: Rubbernecker [quote]ORIGINAL: RCPAUL [size=3]I never wondered what the lite ply was in GP kits. I wanted to know how you could tell the ply from the balsa since they both felt and weighed the same! Paul[/size] [/quote] LOL. I'm in the process of building a PT 20 to teach my daughter to fly and I don't know how a 20 is going to fly it. Weighs a ton and all the ribs did feel like ply. As a matter of fact, lite ply would have weighed less. [:D] John [/quote] My first plane was a PT20 that I built from a GP kit. I learned to fly on it. I used a Norvel .25 with a 9'' prop. Takes a bit of runway to take off, especially if the grass has not been mowed in a while, but in the air it is fine, and very economical. I used ~ 1oz of glow fuel every 6 minutes of flight. I suggest oversizing the wheels if you fly off grass, and do not put anything smaller than a .25. I have been using it recently to improve my skills (I think it is always a good thing to go back to a trainer once in a while), and I think a .35 may be better once you get your wings. But is it a tough plane, I think you can almost walk on the wing. Perfect for those rough first landings... Alberto
Posted on: 8/29/2012 11:23 AM by Author "ululi1970" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11210455

HOw much paint do I need?
I am in the process of finishing my first warbird, a 1/8th Corsair built from a Pica kit. The plane is glassed and ready to be painted. I'd like to use water based paints with a HVLP paint gun and I am wondering How much paint I need to order, and if you have suggestions as to where get it. The plane is to be glow powered, so the whole thing has to be fuel proof to ~ 15%nitro. Thank you Alberto
Posted on: 8/29/2012 11:14 AM by Author "ululi1970" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11210442

RE: ys 91 ac question
Well, it took much longer for the store to get the parts, but at last I got them. At this point, I have replaced the valve cover and gasket, together with the carb and plenum gaskets. Also, replaced the plunger/spring assembly. Unfortunately, things did not change when run. At WOT I can get ~ 3 PSI in the tank, and still no more than 7500 RPM with 15% nitro. Basically, nothing changed, including fuel misting out of the carb during transition. Best performance is obtained with the HSN ~ 3/4 out, and the LSN about 3 turns out. At this point, I am inclined to try to list the engine for parts, and get something new... Alberto
Posted on: 8/4/2012 6:40 PM by Author "ululi1970" in the forum "YS Engines Support"
http://www.rcuniverse.com/forum/fb.asp?m=11181060

A new way to launch a Sig Wonder
A few weeks ago we had a discussion at the flying field on how we could "improve" the launching of my Sig Wonder. I took up the challenge and this video [youtube]http://www.youtube.com/watch?v=s9z67L3Xngw[/youtube] shows the result... I guess I'll go back to hand launch [;)]
Posted on: 6/17/2012 5:20 PM by Author "ululi1970" in the forum "Sport Flying"
http://www.rcuniverse.com/forum/fb.asp?m=11121684

RE: ys 91 ac question
Ok, the manual states to set the mark on the drive washer with the mark on the engine case. I did notice that at this point the piston is not quite at TDC. I guess this is what tande alluded to. Then check the dot on the camshaft. As Four Stroke mentioned, the difference between true TDC and the marks aligned does not amount to a whole tooth off on the camshaft. At this point, I'd stick with the manual. I will set the valve clearance so that the intake is at the low end of the recommended range (~0.002'') and the exhaust at the high end (~0.004''), to account for the higher temperature the exhaust valve is subject to, unless your experience suggests otherwise. With any luck, I should have the valve cover here by Saturday... Alberto
Posted on: 6/13/2012 6:22 AM by Author "ululi1970" in the forum "YS Engines Support"
http://www.rcuniverse.com/forum/fb.asp?m=11116618

RE: ys 91 ac question
Well, I think I am onto something. I noticed a hissing sound coming from the top of the engine when it was being turned slowly. It turns out that the valve cover has a small crack near one of the screw holes, and air escapes off it. As it happens, the seller mentioned a crack that had been taken care of. In fact, it has been epoxyed (or JB welded), but clearly it did not stand the conditions during run. Fortunately, a new cover should not be too expensive. Since I am after parts, anything else I should order just in case? I was thinking about the regulator spring, a new diaphragm and a gasket set... Also, I read somewhere to slightly roughen the bottom of the valve cover to ensure a good fit with the gasket. Is this a good suggestion. One more thing. Is it normal that, without glow plug and turning the prop slowly by hand the regulator opens only every other revolution of the prop? My understanding is that the pressure to open the regulator is controlled by a small opening on the crankshaft, hence my confusion... Hopefully, I will be able to get the cover in a few days, and I'll get back to you with some good news. I thank everybody who contributed. I learned a lot... Alberto
Posted on: 6/12/2012 6:35 PM by Author "ululi1970" in the forum "YS Engines Support"
http://www.rcuniverse.com/forum/fb.asp?m=11115976

RE: ys 91 ac question
Here's what I found so far: 1) The valve clearance is about 0.05mm, so within specs. 2) at TDC, the timing mark on the camshaft is at the top. Based on the manual, that is where it is supposed to be. BTW, to inspect the timing I removed the cover to the camshaft and rotate the cranckshaft. Can the timing be accidentally changed without taking the camshaft out? I do not hink so, and I checked before closing the cover, but just in case. I will do Four Stroke trick as soon as I can get a pressure gauge from the lab... Alberto
Posted on: 6/12/2012 12:20 PM by Author "ululi1970" in the forum "YS Engines Support"
http://www.rcuniverse.com/forum/fb.asp?m=11115786

RE: ys 91 ac question
I am surely gratedul for all the help I can get. I get the best RPM with the HSN ~ 3/4 out, and the LSN ~ 4 1/8 out. I set the HSN by starting at 1 1/2 out as per manual and slowly leaning while checking speed with a tach. The tach btw works, as it gives be 3600 when I point it to a flurescent light in the shop. The regulator screw is slightly out, but I did not see much difference with it flush or even a bit in. The guy who sold it to me said that it had a new ring in it, new diaphragm, bearings, gasket set and needle valve assembly. I will try Four Stroker test to make sure the regulator closes as it is supposed to. Though last time I ran it, I did pull the line from the regulator to the carb with the tank still pressurized, and I did not see any fuel coming out. I may also be able to jury rig a pressure gauge to the tank, to make sure I get enough pressure in the tank. Not sure though, depends what we have in the lab... Alberto
Posted on: 6/11/2012 5:35 PM by Author "ululi1970" in the forum "YS Engines Support"
http://www.rcuniverse.com/forum/fb.asp?m=11114955

RE: ys 91 ac question
I do not have a way to measure pressure in the tank. However, after shutting off the engine, when I disconnect the vent line I hear a hiss for about a second. So there is some pressure in the tank, though I do not know if it is enough. Fuel spews out of the carb intake. I am fairly certain of that. The air chamber is clean, while there is fuel dripping from the bottom of the carb assembly. Not sure if there are other leaks besides the fuel that comes out of the carb intake. Alberto
Posted on: 6/10/2012 12:11 PM by Author "ululi1970" in the forum "YS Engines Support"
http://www.rcuniverse.com/forum/fb.asp?m=11113392

RE: ys 91 ac question
I started thinking that if the regulator does not close properly, it should affect the low end as well, should it not? Yet it idles very well without any tendency to slow down. Also, when I took the glow plug, the element was a nice gray. I would not expect that from an engine that runs rich. So what else could it cause loss of power at high rpm? A worn out ring? Compression seems good, though this being my first ring engine I do not have a baseline to compare to. Also, when it is warm it starts as well as when it is cold. In my experience with automotive engines, warn pistons/rings loose compression as the engine warms up and the cylinders expands, making them harder to start... Also, could it be the 15% nitro is too low? I will try to get a jug of 20/20 for comparison... Alberto
Posted on: 6/10/2012 7:08 AM by Author "ululi1970" in the forum "YS Engines Support"
http://www.rcuniverse.com/forum/fb.asp?m=11113123

RE: ys 91 ac question
One more thing. I remember now that when I took apart the regulator, the crankcase side of the diaphragm was full of fuel (or oil, hard to tell). Is this normal? The engine was stored upside down... IF not, what parts do I need to rebuild the regulator? My understanding is that the pressure applied on the crankcase side pushes the diaphragm against the plunger, and when that happens fuel under pressure from the tank is allowed into the carb. Is that so? Thanks for your help. Alberto
Posted on: 6/9/2012 6:24 PM by Author "ululi1970" in the forum "YS Engines Support"
http://www.rcuniverse.com/forum/fb.asp?m=11112527

RE: ys 91 ac question
I disassembled the regulator, and flush it with fresh fuel. Everything seemed fine. Tried again. Working on both the regulator screw as well as the HSN I was able to get it to spin at 7700 RPM, with some misting coming out of the carb, especially during transition. We are not talking loads of fuel, just small droplets. It holds idle well at 2000... What else could be wrong? Alberto
Posted on: 6/9/2012 11:26 AM by Author "ululi1970" in the forum "YS Engines Support"
http://www.rcuniverse.com/forum/fb.asp?m=11112439

ys 91 ac question
I am starting to get myself acquainted with a 91 ac that I got used a while ago. I am running a 15x8 MA prop, on 15% nitro. It starts without too much fussing. Transitions reasonably smooth. However, I cannot get it to run past 7500rpm. Is this ok, or should I get something more with this prop? Also, I noticed fuel coming out of the carb barrel, especially at mid range. By the end of the run, there is quite some fuel all over the carb. Again, since I am new to 4-stroke engines, not sure if this is normal. Any help is appreciated... Alberto
Posted on: 6/7/2012 2:17 PM by Author "ululi1970" in the forum "YS Engines Support"
http://www.rcuniverse.com/forum/fb.asp?m=11110376

RE: GP F-86 micro edf
Maiden it today.with stock elevator. According to our test pilot it is a nice flyer. Only issues was not being able.to fly inverted due to lack of down elevator. Likely due to very conservative settings on dual rates. 3 minutes on stock battery At wot left the battery at about 3.75 V per cell.
Posted on: 4/29/2012 4:58 PM by Author "ululi1970" in the forum "Electric RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11061683

RE: GP F-86 micro edf
Nice work. I agree with the design flaw idea. I will keep it in mind the first time I'll have to poke around the innards. Have not flown yet, due to bad weather last weekend.
Posted on: 4/27/2012 8:27 PM by Author "ululi1970" in the forum "Electric RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11059659

RE: Glasing question
Ok, it seems that if I do not apply the hairspray liberally the warping occurs after applying the WBPU, while if I apply the hairspray liberally warping occurs right away. Either way, no good. Probably the harispray is not the right one. Pacoflyer suggested a lacquer based one. Will look into it. At this point, if I can't find it I am inclined to go with the DEFT sealer and make sure I do not leave the ship in a hot car... Alberto
Posted on: 4/27/2012 7:02 AM by Author "ululi1970" in the forum "Tips & Techniques"
http://www.rcuniverse.com/forum/fb.asp?m=11058889

RE: Glasing question
I did some experiments with alcohol based hairspray. 2 coats of hairspray, 6 coats of WBPU + fiberglass cloth. Baked at 150F for 1/2 hour, no bubbles/blisters. I did noticed though some warping at the end. Not sure when it started. It may have been there from the beginning, though I noticed only after a couple of coats of WBPU. So now I am doing a final experiment with just a sheet of 1/6'' balsa (no frame). So far the first coat of hairspray went on without warping. The second is drying right now. Will then do the usual WBPU. I reckon that if warping occurs, a plain sheet of balsa should show it. Will check after each coat. My only gripe is that the only hairspray I could find that is alcohol based is scented. What happened to the old cheap hairspray? Alberto
Posted on: 4/26/2012 11:12 AM by Author "ululi1970" in the forum "Tips & Techniques"
http://www.rcuniverse.com/forum/fb.asp?m=11057736

RE: GP F-86 micro edf
There is a long and informative thread on rcgroups about this plane. Lots of people report noticing the problem with the elevator, but also they say that it does not affect flying. So at the moment I am inclined towards leaving it alone. What you say about the CG is absolutely true. Again, the rcgroups thread discusses the issue at length. The consensus seems to be 67-70 mm from the leading edge as it crosses the fuse at the bottom. When you say hand launch mishap, do you mean it went straight up and then straight down? Alberto
Posted on: 4/25/2012 10:28 AM by Author "ululi1970" in the forum "Electric RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11056266

GP F-86 micro edf
I am new to EDF, so before I get on the phone with Tower I thought about asking the experts first. I just received a GP F-86 micro edf today. Everything checks fine, except I noticed that the split elevators do not move the same amount. At maximum deflection (up or down), the right side elevator moves about 1/8', the left side about 1/4' . The manual gives 1/4' for the elevator throw. My feeling is that someone goofed up hooking up the control surfaces to the servo, but I wonder if this differential displacement is in fact needed to counteract engine torque or whatever. As I said, I am new to EDF. Thanks Alberto
Posted on: 4/18/2012 6:16 PM by Author "ululi1970" in the forum "Electric RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11047832

RE: Glasing question
Paul, It is not just discussion. As I mentioned in post 22 above, using deft under poly resulted in blisters forming when heated to 150F. You may argue that 150F is extreme, but it is not unheard of in a car in direct sunlight. Once I left a heli canopy in the car. It basically melted down... Alberto
Posted on: 4/3/2012 11:27 AM by Author "ululi1970" in the forum "Tips & Techniques"
http://www.rcuniverse.com/forum/fb.asp?m=11026845

RE: Glasing question
Ken, I have read about people suggesting the same thing (using the poly as a sealer). I am concerned about the water soaking into the wood and causing warping issues. I think that is the reason it is recommended to use a non water based sealer as a first layer. Of course, I could use a lacquer based polyurethane, which would not require a sealer, but I'd like to avoid dealing with fumes, plus I like being able to clean up stuff with water. I got a can of hairspray and will experiment with that. BTW, there were several types to choose from, most of them listed water as the first ingredient, so I stayed away from them. I picked one that has alcohol as first ingredient and no water at all. I will build another panel and experiment with hairspray+water based poly and report back the results. Alberto
Posted on: 4/3/2012 7:07 AM by Author "ululi1970" in the forum "Tips & Techniques"
http://www.rcuniverse.com/forum/fb.asp?m=11026465

RE: Glasing question
[quote]ORIGINAL: pacoflyer I've used Final Net hairspray for years before I do any glassing. It seems to cut down on the absorption of the resin into the bare wood. paul [/quote] Is this the non-aerosol (no propellant)? Alberto
Posted on: 4/2/2012 10:37 AM by Author "ululi1970" in the forum "Tips & Techniques"
http://www.rcuniverse.com/forum/fb.asp?m=11025174

RE: Glasing question
This has been a most interesting thread to read, and I thank you all for providing expertise. Earlier I mentioned that I was going to experiment on a small panel. The panel was made sheeting on both side a 6''x6'' stick frame with 1/16 balsa. I applied 2 coats of DEFT sandable sealer, sanded after the second coat, 6 coats of minwax polycrylic over .7 oz glass cloth, sanding between each coat after the second, followed by two coats of primer/filler sanded down plus a final coat. I waited 6 days after the last application of sansable sealer before applying the glass/polycrylic. The latter was applied over a period of a week. Up to the primer, everything went well. I was surprised how easy it was to work with this stuff, and how good it looked by the end. HOWEVER, I decided to make a last test, and after waiting for the primer to dry over several days, I placed the panel in a convection over set at 150F. The idea was to simulate the inside of a car left in the sun on a hot summer day (I live in North Carolina). After about 1/2 hour in the oven, blisters started to develop! They appeared randomly over both sides. This problem has been reported in other posts, and my test confirms it. The working hypothesis, is that there are adhesion problems between minwax polycrylic and te lacquer based sealer that show up when the temperature goes up. Some people suggested it is due to solvent in the lacquer being trapped under the polycrylic. Note that I waited 6 days for the sealer to dry, during which the max daily temp reached ~80F and the min ~55F. So beware, if you operate in warm climates... I want to make an experiment mow using hairspray as a sealer. Any suggestion on brands?
Posted on: 4/2/2012 9:15 AM by Author "ululi1970" in the forum "Tips & Techniques"
http://www.rcuniverse.com/forum/fb.asp?m=11025075