RE: Some technical Cox 049 questions
[quote]ORIGINAL: BMatthews You CAN run that combo but due to the limitations of the reed style intake and the extra length of the choke tube style intake you will likely not see any RPM gain over the more simple two bypass flute style cylinder. The increased compression may or may not work out. You'd need to try it. If the increase in compression combined with the less than true "small prop" Tee Dee style RPM results in firing too early you'll simply beat up the engine and not see a gain in RPM. For example even with a Tee Dee the high comp head needs a fairly free running prop. The one time I ran my own Tee Dee for a lot of runs on a model using a 5x3 prop it ran like crud for the first few flights. Eventually it darn near stopped. Seems I'd been getting so early ignition that I busted the seal on the plug. I replaced it with a regular straight cone style plug and it ran much stronger and smoother immediately. Never looked back and have not seen a need to try another high comp head for the sort of flying I do. Oh, I tend to run at LEAST 25% nitro for my 1/2A engines all the time other than on my Tecaco models where it's 5%. [/quote] Mr. Matthews, I hope you don't mind but I passed this along to another Cox engine user at coxengineforum.com. He had a problem that I thought your post might help him to solve. Thanks for sharing your insights, Bob
Posted on: 9/5/2012 10:57 AM by Author "fit90" in the forum ""1/2 A" & "1/8 A" airplanes"
http://www.rcuniverse.com/forum/fb.asp?m=11218406

RE: Some technical Cox 049 questions
[quote]ORIGINAL: TampaRC Can the stock piston/cylinder/glowplug on the choke tube engine be replaced with the TD piston/cylinder and hi comp plug ? With positive results? What about adding Bernies Killer Bee back plate on top of that? Then where will I be performance wise? Q #2 Lets say I have a TD .051 with a worn cylinder and piston. Can I install an .049 TD cyl/piston? [/quote] Yes, you can use both a Tee Dee piston/cylinder and a Killer Bee backplate on a Sure Start. Both should yield a mild increase in performance. But, all Cox engines respond to different parts differently so running the engine after the changes will be the only way to tell. I suggest making only one change at atime so you can quantify your results. Yes, an .051 piston/cylinder can be replaced with an .049
Posted on: 9/4/2012 4:22 PM by Author "fit90" in the forum ""1/2 A" & "1/8 A" airplanes"
http://www.rcuniverse.com/forum/fb.asp?m=11217549

RE: How does bottom-hinged aileron affect flying?
Mr. Matthews is absolutely correct. I apologize for the misinformation. Top hinging can be a very good part of differential ailerons though. By making the trailing edge of the wing perpendicular to its chord line and puting a receding angle on the front of an aileron (meaning the top part of the aileron leading edge is closer to the wing's trailing edge than the bottom part) then when differential occurs via control actuators ( usually via a difference between the angle of stick to bell crank and angle of bell crank to control surface) then the more the aileron is deflected downward the smaller the gap between the bottom of the wing and aileron gets while using the aileron hinge effectively as a gap seal between the wing's upper trailing edge and the aileron. I hoe this wordy explanation helps and not hurts. Bob
Posted on: 8/11/2012 4:09 PM by Author "fit90" in the forum ""1/2 A" & "1/8 A" airplanes"
http://www.rcuniverse.com/forum/fb.asp?m=11189701

RE: How does bottom-hinged aileron affect flying?
Many full size planes have the ailerons hinged "on the top" so that the aileron can move farther in the up direction that in the down direction. This can be desirable because when the aileron moves down it creates lift and also induced drag. This creates more drag on the downward moving aileron side of the plane causing the plane to yaw in that direction. To counter this, the up moving ailereon is often moved approximately twice as far up as the downward moving aileron goes down. This causes the upward moving aileron to create parasite drag which counters the induced drag eliminating the yaw.
Posted on: 8/10/2012 5:56 AM by Author "fit90" in the forum ""1/2 A" & "1/8 A" airplanes"
http://www.rcuniverse.com/forum/fb.asp?m=11188005

RE: A GLH for 2012
[quote]ORIGINAL: combatpigg [quote]ORIGINAL: hllywdb [quote]Our local field is total fuddy-duddy stuff only. [/quote] Do you want me to stop by and help you ruin the neighborhood? [/quote] The people who bought land East of the field would probably use their "Medic Alert 911" dialers if you showed up there with your GLH. The farmer to the South of the field would blame your plane for sour milk and has taken shots at planes that over fly his corn field. So yah..come on out here and we'll go on a drunken rampage with our 1/2A speedsters..! [/quote] If you guys do that please video it. It would be hilarious! Bob
Posted on: 8/2/2012 6:24 PM by Author "fit90" in the forum ""1/2 A" & "1/8 A" airplanes"
http://www.rcuniverse.com/forum/fb.asp?m=11179131

RE: A GLH for 2012
How big a prop are you turning? My Norvel .061 AME likes one shim on a Galbreath head/Nelson plug combo too, but I only use 25% and the prop is never any bigger than an APC 5.7 X 3 cut down to 5 X 3.. Everything is steady as clockwork with this set up. I live in Naples so I would think we are flying under pretty much the same conditions. The plane looks great. Your picture with the plane next to the radio made it clear how much thinner the airfoil is and how much shorter the fuse is. Glad to hear the maiden went so well. I hope you have a lot of fun with this one. Bob
Posted on: 7/31/2012 6:29 PM by Author "fit90" in the forum ""1/2 A" & "1/8 A" airplanes"
http://www.rcuniverse.com/forum/fb.asp?m=11176570

RE: A GLH for 2012
I use pressure to help with fuel draw with enlarged intake holes and to help get a staedier needle valve setting through out the engine run. It also makes fuel tank location less critical. Pretty much all the same reasons as with a Tee Dee or Norvel. Plus, it's just fun to play with the little engines and to get them to turn so fast. Sorry for the hijack 7700 Bob
Posted on: 7/17/2012 5:24 PM by Author "fit90" in the forum ""1/2 A" & "1/8 A" airplanes"
http://www.rcuniverse.com/forum/fb.asp?m=11159246

RE: A GLH for 2012
The picture doesn't explain squat. I definitely prefer the machined cases over the die cast cases. I like to drill through the side of the crank case in one of the spots where it is rounded on the corner for the backplate mounting screw hole. The hole should come through to the crankshaft groove on the inside of the case. Then I take some brass fuel tubing filled with solder and press it into the hole. Drill a #75 hole through the solder and you are good to go.
Posted on: 7/17/2012 4:58 PM by Author "fit90" in the forum ""1/2 A" & "1/8 A" airplanes"
http://www.rcuniverse.com/forum/fb.asp?m=11159197

RE: A GLH for 2012
Glad I waited. My computer does not like this site.
Posted on: 7/17/2012 4:52 PM by Author "fit90" in the forum ""1/2 A" & "1/8 A" airplanes"
http://www.rcuniverse.com/forum/fb.asp?m=11159189

RE: A GLH for 2012
I will post an explanation after I see if the pictures are worth while.
Posted on: 7/17/2012 4:48 PM by Author "fit90" in the forum ""1/2 A" & "1/8 A" airplanes"
http://www.rcuniverse.com/forum/fb.asp?m=11159180

RE: A GLH for 2012
No performance benefit. The check valve allows the pressure line to be used as the overflow for filling the tank without also filling the crankcase. I have found that some engines are a little more user friendly with a check valve, usually Cox reedies, though.
Posted on: 7/17/2012 3:53 PM by Author "fit90" in the forum ""1/2 A" & "1/8 A" airplanes"
http://www.rcuniverse.com/forum/fb.asp?m=11159105

RE: A GLH for 2012
It's a Perry check valve. I got it from Tower Hobbies. Kavan also makes an aluminum check valve that is usually available through Hobby Lobby. Your GLH is really looking great. I am anxious to read the flight report. Bob
Posted on: 7/16/2012 3:58 PM by Author "fit90" in the forum ""1/2 A" & "1/8 A" airplanes"
http://www.rcuniverse.com/forum/fb.asp?m=11157779

RE: A GLH for 2012
Hope the picture works, Bob
Posted on: 7/15/2012 2:26 PM by Author "fit90" in the forum ""1/2 A" & "1/8 A" airplanes"
http://www.rcuniverse.com/forum/fb.asp?m=11156312

RE: A GLH for 2012
I like to run the pressure line directly back through the fire wall with a one way check valve then a tee fitting then to the fuel tank. I use the line from the tee fitting for overflow and the check valve keeps it from flooding the engine crank case. There is a pic in post #47. I like to cap the over flow line with a solid aircraft rivet.
Posted on: 7/15/2012 2:24 PM by Author "fit90" in the forum ""1/2 A" & "1/8 A" airplanes"
http://www.rcuniverse.com/forum/fb.asp?m=11156310

RE: A GLH for 2012
I have used the Texas Timer radial mount back plate for a Cox Tee Dee and put about 1/8" of J B Weld in it and then drilled and tapped it for a 4-40 pressure nipple. I J B Welded the nipple in place. I am trying to load a picture but am not having any luck. Bob
Posted on: 7/14/2012 11:57 AM by Author "fit90" in the forum ""1/2 A" & "1/8 A" airplanes"
http://www.rcuniverse.com/forum/fb.asp?m=11155074

RE: A GLH for 2012
[quote]ORIGINAL: hllywdb That's the stuff you never see show up in a surplus store! There was a guy down here in FL a few years back that had an old river gun boat that he was using for a treasure/dive boat. He took the gas turbine water jet drives out and put in a couple of disels. Had a big metal plate bolted down where the gun turret was on the front. Said it was real stable offshore. Me, I'd just be happy with an old F4 Phantom. Don't even care what color, I can paint. To me they encompass what a fighter jet should look like. Plus I grew up on Quanssett Point watching the Blue Angels fly them in the 60's. Forget small and nimble fighters, watching those F4's put on a show was the original "Shock and Awe." Awe crap, I hijacked my own thread again! [/quote] Do you know what kind of boat it was? Was it about 21' long with a fiberglass coated balsa hull? In the late 80's/early 90's the Navy was getting out of the PBR (patrol boat, riverine) game. We were overhauling our boat to give to Belize. At the time it had a pair of Detroit 250's. I was told that it was used in the Vietnam war and was outfitted with a pair of Chevy 427's back then. The engines each drove a Jacuzzi "jet" pump. It had a pair of M-2's up front. It was a fun boat, probably because of the great guys as much as the boat. It would be cool to know at least one came back to the U. S. Bob
Posted on: 7/13/2012 5:23 PM by Author "fit90" in the forum ""1/2 A" & "1/8 A" airplanes"
http://www.rcuniverse.com/forum/fb.asp?m=11154326

RE: Scalpel Flight Video
Looked pretty fast to me. I hope you can get the piston lightened again. It also looked like the engine was really starting to loosen up. All in all, it looks like a great flying plane. I will probably get one when I see them up on the select hobbies website. If I do I will be sure to include a note saying I saw it here but I am sure this post will suffice as that note.
Posted on: 7/3/2012 3:20 PM by Author "fit90" in the forum ""1/2 A" & "1/8 A" airplanes"
http://www.rcuniverse.com/forum/fb.asp?m=11141762

RE: Kadetito
It looks great! Let us know how it flies.
Posted on: 6/3/2012 4:17 PM by Author "fit90" in the forum ""1/2 A" & "1/8 A" airplanes"
http://www.rcuniverse.com/forum/fb.asp?m=11105090

RE: Minnie Mambo
Looks great! The wheels add a lot of personality.
Posted on: 3/6/2012 5:11 AM by Author "fit90" in the forum ""1/2 A" & "1/8 A" airplanes"
http://www.rcuniverse.com/forum/fb.asp?m=10988456

RE: Flight Pack with Micro JST Connectors
Horizon Hobby also sells an adapter. I am using it on an ESC with a JR connector on a Spektrum 6300 rx.
Posted on: 3/5/2012 6:19 AM by Author "fit90" in the forum ""1/2 A" & "1/8 A" airplanes"
http://www.rcuniverse.com/forum/fb.asp?m=10987171

RE: Mini F-16 vintage project consideration
The tap on the plastic venturi body is supposedly the best method, something to do with it being timed to crankshaft rotation,timing I think. The backplate tap is just simple. It stays on better without modification and the pressure nipple is not so fragile. Plumbing depends on your set up.
Posted on: 3/2/2012 12:14 PM by Author "fit90" in the forum ""1/2 A" & "1/8 A" airplanes"
http://www.rcuniverse.com/forum/fb.asp?m=10984057

RE: Mini F-16 vintage project consideration
If you decide to use the pressure tapped backplate then some people like to put the check valve between the backplate and the fuel tank. This keeps the crank case from flooding when fueling, especially if you do not have access to the line from the backplate to the tank.
Posted on: 3/2/2012 8:47 AM by Author "fit90" in the forum ""1/2 A" & "1/8 A" airplanes"
http://www.rcuniverse.com/forum/fb.asp?m=10983863

RE: 100 MPH GLH ASP .12...???
I am glad to learn the hole in the pressure fitting is not critical. I can't tell you how many #65 and smaller bits I have broken trying to keep thst stupid hole small. Thanks for the heads up, much appreciated. Bob
Posted on: 2/14/2012 10:38 AM by Author "fit90" in the forum ""1/2 A" & "1/8 A" airplanes"
http://www.rcuniverse.com/forum/fb.asp?m=10958662

RE: Scalpel Build
That looks great! I can't wait to hear how well it flies. I like the machined aluminum spinner too. I think it compliments the nice machine work and anodizing of the engine. Great job, Bob
Posted on: 2/8/2012 5:04 PM by Author "fit90" in the forum ""1/2 A" & "1/8 A" airplanes"
http://www.rcuniverse.com/forum/fb.asp?m=10950393

RE: Scalpel Build
Tee Bee, Looking really good. Nice and clean. Never worry about the building pace. Life always seems to come first and the planes almost always seem to get done. In the next few weeks I hope to finish up a two channel DNU I have been working on for at least six months. I would take it out from under the bed every once in a while just to blow the dust off it and look at it. I have enjoyed the build thread and am looking forward to hearing how it goes on the maiden. By the way, I understand the all show and not too much go on the engines. I have some Valentine 1/2a's that are really beautiful but don not turn up anywhere near what I had hoped for. They sure are pretty, though. Bob
Posted on: 2/4/2012 4:52 PM by Author "fit90" in the forum ""1/2 A" & "1/8 A" airplanes"
http://www.rcuniverse.com/forum/fb.asp?m=10944046

RE: .074 MARAUDER !!!
[quote]ORIGINAL: skaliwag Times are tough .. but a "Hand Launch" shouldn't cost that much .. No? [/quote] It all sounds like simple supply and demand economics to me. You better suppy what she wants as soon as she demands it.
Posted on: 1/14/2012 7:24 AM by Author "fit90" in the forum ""1/2 A" & "1/8 A" airplanes"
http://www.rcuniverse.com/forum/fb.asp?m=10908243

RE: How to clone a Cox Venom
I thought the original Venom had a tapered cylinder. I am not positive, though. Bernie, When you make the Venom II will it use standard height, lightened pistons? If so, will you also sell them seperately or with cylinders? I bet a lot of tinkerers would go nuts for those. Bob
Posted on: 11/6/2011 10:00 AM by Author "fit90" in the forum ""1/2 A" & "1/8 A" airplanes"
http://www.rcuniverse.com/forum/fb.asp?m=10799374

RE: Super Tigre X.11
That thing looks like it will be blazing fast!
Posted on: 11/4/2011 4:51 PM by Author "fit90" in the forum ""1/2 A" & "1/8 A" airplanes"
http://www.rcuniverse.com/forum/fb.asp?m=10797182

RE: 051 Tee Dee Cloning to a .050 Tee Dee R/C
First pic was taken about where I turn base to final, second was taken from about where I stand when flying-looking at the area where I turn base to final.
Posted on: 9/18/2011 3:49 PM by Author "fit90" in the forum ""1/2 A" & "1/8 A" airplanes"
http://www.rcuniverse.com/forum/fb.asp?m=10722963

RE: 051 Tee Dee Cloning to a .050 Tee Dee R/C
Mr. Cox, You are aabsolutely right. However, I occasionally fly out of my front yard and it is heavily wooded with thick and tall pines, palms and oaks. My landing area is narrow, short and closely surrounded by trees. I normally fly electrics at home just so I can kill the power completely to make it in but sometimes I just need to put up a plane with a heart and soul (wet powered) and it breaks my heart when the planes end up spending several nights out in the trees because of my dumb thumbs. You are right about the large sacrafice on the top end RPM though. This same engine with a #4 cylinder and a Galbreath head and Nelson plug would run beautifully from about 6,000 RPM to about 18-19,000 RPM with this prop and fuel. This would be a great power range for most planes. Besides, I also wanted to see how low I could make this baby idle just for kicks. I wlll try to get a pic of my front yard up soon so you can see what I mean. Also, the sound of a whining Cox still draws lots of attention from the neighborhood kids. Bob
Posted on: 9/18/2011 3:12 PM by Author "fit90" in the forum ""1/2 A" & "1/8 A" airplanes"
http://www.rcuniverse.com/forum/fb.asp?m=10722915