Club FOX!
01-20-2014, 08:33 PM
#3251
Around 25 years ago, one of our club members decided to try an Eagle II, even though he thought it was one ugly brute. Also in spite of a number of Fox haters. He put it into a Midwest Mach 1, about 8.5 pounds. Although he was pleased with the flying, he converted to Fox engines when a large oak tree jumped in front of his plane while doing a low altitude high speed pass (actually, receiver went bad-maybe). When he pulled the engine out of the tree, where it actually penetrated like an arrow head, all he needed to do was replace prop, needles, plane, and radio. The engine was the only part that survived. He was still using that engine 10 years later when he moved to California. And he had several more Fox engines as well. Major complaint I have with one of my eagles, using lots of castor, this engine took at least 10 years with 20 or more flights a year to break in to the point where I could start on the first try of the day with a starter instead of a hefty chicken stick, and run out a full tank. I think it will outlive me.
01-21-2014, 06:29 AM
#3252
Join Date: Aug 2010
Location: calgary, AB, CANADA
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I have a fox 40 standard BB engine that I bought nearly 25 years ago, used to have it in a Falcon 56. I put it away nearly 20 years ago and haven't run it since. On sunday I got it out the box, turned it over a few times, it was a bit stiff from the after run oil. The carb rotor was stuck so had to free it up as well. I put it on my test stand and it fired up right away. Needle settings were off some but it ran really strong 12,600 rpm with a 10-6 prop and I still had it running rich. Was very pleased with the way it performed. Will have to get it up in the air again this summer.
01-21-2014, 07:42 AM
#3253
Over time there have been several methods used to try to reduce the oil being pushed out of the front bearing area on the model engines. The crankcase pressure pulses in a two stroke engine are quite strong and can push fuel and oil out of the front end of the engine.
Early on the model engines all used a bushed front end for the crankshaft. You really needed to have a thin layer of oil there to prevent the crankshaft from touching the bushing in the front end. There was also a fine balance needed so that there was a appropriate gap or space to allow the oil to flow through but not so close as to increase drag too much or be loo loose and allow for too much play on the crankshaft or even for air leaks to occur. The problem for performance was drag with higher performance. The drag was the interaction between the oil film and the crankshaft inside the front end would limit the RPMs. Later someone started putting in needle bearing and or ball bearings and getting more RPMs out of the engines and that set off the arms race, so to speak then.
At first the engines used a single bearing at the rear, either needle or ball bearings were used. This tended to help prevent wear on the rear of the crankshaft from the power strokes in the engine causing the bushing to become oval shaped which hurts performance of course. One issue is the compression goes down slightly and wear on the connecting rod increases. Using a ball bearing or needle bearing helps prevent that and also reduces drag some yielding more RPMS or power of course.
Then the dual bearings started being used at both ends of the crankshaft. One performance technique was to open up the gap evwer so slightly between the crankshaft and the front end in between the bearings to reduce the slight drag that was there from the oil film. But if you went to far, you caused a air leak to occur. The engines still oozed oil out of the front end at this time.
Then the world started to change, newer modellers or hobbyists using the engines in airplanes were being annoyed by the excess oil being deposited on their planes. Prior to this time, people didn't really care, they were all used to it as all the engines were messy anyway. But newer people noticed it and were somewhat annoyed by the excess oil residue on the planes.
I think OS was the first to take notice of this change and they started coming up with ways to reduce the oil messiness of the model engines. Also the glow fuel companies started reducing the oil content in glow fuels. But this was more to do with oil costs though. It still had a effect on reducing oil residue though.
One method was to use a shielded or sealed front bearing. This had the effect of blocking off the front end from being able to ooze oil out of the front. They also close up the gap between the crankshaft and the front end behind the front bearing more to help keep the pressure pulses from weakening the seal and causing it to leak. But the problem winds up being that the oil or grease in the bearing tends to migrate out over time and the bearing dries out and or the seal weakens allowing the oil to leak out too. So the bearings have a limited life like that.
Then someone started using a short shallow groove from the front bearing to the intake port on the engine. The bearing may or may not have both seals or shields on both sides in this case. The short shallow groove is open on the intake suction stroke and it helps suck oil away from the front bearing. Normally this works fine, but the groove depth is critical and if the front bearing seals start to leak and let air in, then a air leak develops causing all sorts of odd problems when trying to adjust or tune the engine. You usually saw problems like with is the cheapie low cost engines, the major brand names usually didn't have a problem unless the engine had become old and sat around a lot between uses allowing the front bearing seals to deteriorate over time. The oil actually helps preserve the seals in the bearing.
The next more subtle technique was instead of a groove was to drill a tiny hole there where one would put in a groove. The hole served the same purpose as the groove did. It allowed the engine to suck excess oil away from the front bearing. The hole was angled so that it could suck oil from the inner base of the the seal on the bearing. You could not normally see it unless you removed the front bearing. This method works Ok, unless the front bearing seals go bad over time too. If the engine sat around for a long time the tiny hole tended to get stopped up with congealed castor oil or old bearing seal debris. The positioning of the hole has to be done correctly, which wasn't the case with the el'cheapo engines though.
Another technique was to use a shallow spiral groove cut into the crankshaft. The spiral was cut so that the groove would pull oil away from the front end. They did this on both bushed and ball bearing engines. Depending on how the grooves were cut one could allow for some oil or no oil to migrate forwards.
But one problem people usually don't think about is the ball bearing specifications themselves. There is a whole art and science involved into which bearings to use for what purpose. Model airplane engines have both axial and radial loads applied to the bearings. Unfortunately some engine companies, especially the cheapie engine companies tend to ignore that and use the cheapest bearings they can get. Some other companies may use the wrong bearing type as it reduces cost and with early bearing failues they can sell more new engines of course. Some companies still specify the proper ball bearings to use and those bearings tend to wear well and not wear out fast. The other issue is the materials used to make the bearings with, whether it is lower quality steel alloys or higher quality stuff.
This is probably more information that most people are interested in but here is one reference to it http://nhbb.com/files/catalog_pages/HiTech_Catalog.pdf
It also seems that over the years the throw away engine concept has developed. I think the accountants at the engine companies really like this as it sells more engines. Thus instead of making a really high quality product, make something that tends to work OK, and if it quits working or something, throw it away and get another one. Not having spare parts or limiting spare parts available or making the parts very expensive tends to play right into this type of thinking too. Not having engines last a long time and no spares really does reduce costs and increase profits too. Whether a company passes the cost savings along or not is debatable though.
Early on the model engines all used a bushed front end for the crankshaft. You really needed to have a thin layer of oil there to prevent the crankshaft from touching the bushing in the front end. There was also a fine balance needed so that there was a appropriate gap or space to allow the oil to flow through but not so close as to increase drag too much or be loo loose and allow for too much play on the crankshaft or even for air leaks to occur. The problem for performance was drag with higher performance. The drag was the interaction between the oil film and the crankshaft inside the front end would limit the RPMs. Later someone started putting in needle bearing and or ball bearings and getting more RPMs out of the engines and that set off the arms race, so to speak then.
At first the engines used a single bearing at the rear, either needle or ball bearings were used. This tended to help prevent wear on the rear of the crankshaft from the power strokes in the engine causing the bushing to become oval shaped which hurts performance of course. One issue is the compression goes down slightly and wear on the connecting rod increases. Using a ball bearing or needle bearing helps prevent that and also reduces drag some yielding more RPMS or power of course.
Then the dual bearings started being used at both ends of the crankshaft. One performance technique was to open up the gap evwer so slightly between the crankshaft and the front end in between the bearings to reduce the slight drag that was there from the oil film. But if you went to far, you caused a air leak to occur. The engines still oozed oil out of the front end at this time.
Then the world started to change, newer modellers or hobbyists using the engines in airplanes were being annoyed by the excess oil being deposited on their planes. Prior to this time, people didn't really care, they were all used to it as all the engines were messy anyway. But newer people noticed it and were somewhat annoyed by the excess oil residue on the planes.
I think OS was the first to take notice of this change and they started coming up with ways to reduce the oil messiness of the model engines. Also the glow fuel companies started reducing the oil content in glow fuels. But this was more to do with oil costs though. It still had a effect on reducing oil residue though.
One method was to use a shielded or sealed front bearing. This had the effect of blocking off the front end from being able to ooze oil out of the front. They also close up the gap between the crankshaft and the front end behind the front bearing more to help keep the pressure pulses from weakening the seal and causing it to leak. But the problem winds up being that the oil or grease in the bearing tends to migrate out over time and the bearing dries out and or the seal weakens allowing the oil to leak out too. So the bearings have a limited life like that.
Then someone started using a short shallow groove from the front bearing to the intake port on the engine. The bearing may or may not have both seals or shields on both sides in this case. The short shallow groove is open on the intake suction stroke and it helps suck oil away from the front bearing. Normally this works fine, but the groove depth is critical and if the front bearing seals start to leak and let air in, then a air leak develops causing all sorts of odd problems when trying to adjust or tune the engine. You usually saw problems like with is the cheapie low cost engines, the major brand names usually didn't have a problem unless the engine had become old and sat around a lot between uses allowing the front bearing seals to deteriorate over time. The oil actually helps preserve the seals in the bearing.
The next more subtle technique was instead of a groove was to drill a tiny hole there where one would put in a groove. The hole served the same purpose as the groove did. It allowed the engine to suck excess oil away from the front bearing. The hole was angled so that it could suck oil from the inner base of the the seal on the bearing. You could not normally see it unless you removed the front bearing. This method works Ok, unless the front bearing seals go bad over time too. If the engine sat around for a long time the tiny hole tended to get stopped up with congealed castor oil or old bearing seal debris. The positioning of the hole has to be done correctly, which wasn't the case with the el'cheapo engines though.
Another technique was to use a shallow spiral groove cut into the crankshaft. The spiral was cut so that the groove would pull oil away from the front end. They did this on both bushed and ball bearing engines. Depending on how the grooves were cut one could allow for some oil or no oil to migrate forwards.
But one problem people usually don't think about is the ball bearing specifications themselves. There is a whole art and science involved into which bearings to use for what purpose. Model airplane engines have both axial and radial loads applied to the bearings. Unfortunately some engine companies, especially the cheapie engine companies tend to ignore that and use the cheapest bearings they can get. Some other companies may use the wrong bearing type as it reduces cost and with early bearing failues they can sell more new engines of course. Some companies still specify the proper ball bearings to use and those bearings tend to wear well and not wear out fast. The other issue is the materials used to make the bearings with, whether it is lower quality steel alloys or higher quality stuff.
This is probably more information that most people are interested in but here is one reference to it http://nhbb.com/files/catalog_pages/HiTech_Catalog.pdf
It also seems that over the years the throw away engine concept has developed. I think the accountants at the engine companies really like this as it sells more engines. Thus instead of making a really high quality product, make something that tends to work OK, and if it quits working or something, throw it away and get another one. Not having spare parts or limiting spare parts available or making the parts very expensive tends to play right into this type of thinking too. Not having engines last a long time and no spares really does reduce costs and increase profits too. Whether a company passes the cost savings along or not is debatable though.
Last edited by earlwb; 01-21-2014 at 07:48 AM. Reason: add more info
01-21-2014, 11:45 AM
#3256
Does anybody have a picture of the Fox 40 RC Sport, the small bushing version? The Fox website picture is not clear and I would like to find out more about them. Are those still iron piston and lapped steel cylinder?
01-21-2014, 03:16 PM
#3258
Join Date: Jun 2012
Location: Hervey Bay, AUSTRALIA
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G'day Gent's thanks very much for your help, it's very much appreciated.
I was basically given that eng and muff, as I say I had no idea about it or it's size. I'll soak it in some light machine oil when I get a chance and then look at putting it on a stand and running it, I'll probably be getting back to you asking about settings etc when I get to that stage
Cheers and once again thanks very much
I was basically given that eng and muff, as I say I had no idea about it or it's size. I'll soak it in some light machine oil when I get a chance and then look at putting it on a stand and running it, I'll probably be getting back to you asking about settings etc when I get to that stage
Cheers and once again thanks very much
01-21-2014, 04:14 PM
#3259
G'day Gent's thanks very much for your help, it's very much appreciated.
I was basically given that eng and muff, as I say I had no idea about it or it's size. I'll soak it in some light machine oil when I get a chance and then look at putting it on a stand and running it, I'll probably be getting back to you asking about settings etc when I get to that stage
Cheers and once again thanks very much
I was basically given that eng and muff, as I say I had no idea about it or it's size. I'll soak it in some light machine oil when I get a chance and then look at putting it on a stand and running it, I'll probably be getting back to you asking about settings etc when I get to that stage
Cheers and once again thanks very much
01-21-2014, 05:45 PM
#3260
My Feedback: (13)
Join Date: Jun 2010
Location: baton rouge 70811,
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I guest I will join to I have 36 x rear muffler 4 old styles 40s 5 new styles 40s 1 46 3old styles 45s 2 50s 1 60 eagle 1 bushing 40 and the all run like a top. on the motor that run on a prime and stop you can take a tip cleaner after you take the needle valves off the carb.and push it tthrogh the carb .you can check your needle valves to . I ben flying fox engines for over 30 years,
01-21-2014, 07:13 PM
#3261
yes the small frame .40 is a lapped piston steel sleeved engine. They actually are not much larger than a big .25 through .36 engine actually. so one could use them as a performance upgrade for a .25 size plane. The engine is slightly more wide, but not by much though. The carb has a square base that fits into a square hole in the crankcase intake. The engines were originally .29x and .36x combat CL engines thus the square hole in them. They are Schnuerle ported too.
ref http://www.fayettevillercclub.com/id59.html
Fox did make some with a ABC piston and cylinder, but he did have trouble getting it to work right though.
ref post 2655 here http://www.rcuniverse.com/forum/glow...b-fox-107.html
ref http://www.fayettevillercclub.com/id59.html
Fox did make some with a ABC piston and cylinder, but he did have trouble getting it to work right though.
ref post 2655 here http://www.rcuniverse.com/forum/glow...b-fox-107.html
01-22-2014, 07:17 AM
#3263
The Fox website mentions that a BB or bushed version is available for the 40 Sport. Any experience with either? What fuel blend does it take, all castor, how much nitro? Thanks.
01-22-2014, 08:17 AM
#3264
I suspect it is to use 20% castor oil fuel with about 10% nitro. Or seems I have seen some such here. But why don't you call. I have found them slow to respond by e-mail, but very helpful when you give them a call.
01-22-2014, 08:29 AM
#3265
I've been thinking of calling them soon after I make a list of questions to ask. I have talked to them direct in the past and they were always helpful. I was just trying to decide whether I want the bushing 40 or the bigger 45BB. Too many choices. I might want to sell an old engine first.
01-22-2014, 09:11 AM
#3266
The larger case .45 is probably the better engine as I believe it has a stronger rod. Davis makes or used to make a diesel head for the large case .45 where they didn't for the small C case engines because of the rod strength. That's not to say the small case engines don't perform well. You just have to figure a .40 displacement in a .25 case would usually mean the ports are shallower and thus more restrictive port flow. I don't know if this is the case with Fox engines though so I'm merely speculating.
01-22-2014, 09:30 AM
#3267
The larger case .45 is probably the better engine as I believe it has a stronger rod. Davis makes or used to make a diesel head for the large case .45 where they didn't for the small C case engines because of the rod strength. That's not to say the small case engines don't perform well. You just have to figure a .40 displacement in a .25 case would usually mean the ports are shallower and thus more restrictive port flow. I don't know if this is the case with Fox engines though so I'm merely speculating.
01-22-2014, 11:03 AM
#3269
They are all still listed. However, I don't know of availability yet since I have not called Fox yet. Anyway, I am not in a hurry, I will just buy it whenever it becomes available.
I also don't know which carb they come with now. I really would like to have the newer 2-needle version.
I also don't know which carb they come with now. I really would like to have the newer 2-needle version.
01-22-2014, 12:34 PM
#3270
The Fox Quickie engine is a all out racing engine. The engine has very aggressive porting for racing and a larger bore carb. So fuel draw can be a bit weak. Thus the fuel tank location can be more critical with it. That was the main problem folks had racing them was the fuel draw caused problems, it would tend to lean out in the high Gee turns. Make sure the muffler pressure is there or maybe use something to increase pressure to the fuel tank. Also the carburetor on a racing engine is there to primarily kill the engine, usually the carb is full throttle or kill the engine, there isn't a lot of throttling involved, since everyone goes full throttle and turn left. I remember some guys getting frustrated as the engine would not idle. You can get them to slow down some with the carb, but they are not going to idle very slow at all with the radical port timing. It is analogous to trying to drive a nitro supercharged dragster in downtown traffic during rush hour.
But since they don't really use them much for racing nowadays, one could put on a stock carburetor to improve fuel draw. You only lose a little off the top end like that. You could also use crankcase pressure. One could use a bladder tank as well. Using a fuel pump ought to work, but I haven't tried it. Using crankcase pressure offers the cheapest bang for the buck though. One could use a Cline Regulator and crankcase pressure too. But if you are running full throttle you may not need the regulator unless the needle valve becomes too sensitive to adjust.
Here is the engine review I posted about the engine a while back here http://www.rcuniverse.com/forum/glow...l#post10999716
But since they don't really use them much for racing nowadays, one could put on a stock carburetor to improve fuel draw. You only lose a little off the top end like that. You could also use crankcase pressure. One could use a bladder tank as well. Using a fuel pump ought to work, but I haven't tried it. Using crankcase pressure offers the cheapest bang for the buck though. One could use a Cline Regulator and crankcase pressure too. But if you are running full throttle you may not need the regulator unless the needle valve becomes too sensitive to adjust.
Here is the engine review I posted about the engine a while back here http://www.rcuniverse.com/forum/glow...l#post10999716
Last edited by earlwb; 01-22-2014 at 12:37 PM. Reason: add more information
01-22-2014, 05:43 PM
#3271
My Feedback: (2)
I'm building a Sig Wonder and thinking of a Fox .15 for it. I have a few questions that maybe you gents can help me with...
-Is the current production Fox .15 a problem free engine? No carb or head button issues for me to deal with?
-What kind of engine is it? Lapped iron piston / steel sleeve, ABC, ringed? Sleeve or ball bearings?
-How loud is the stock muffler? My field has a sound limit.
Thanks!
-Is the current production Fox .15 a problem free engine? No carb or head button issues for me to deal with?
-What kind of engine is it? Lapped iron piston / steel sleeve, ABC, ringed? Sleeve or ball bearings?
-How loud is the stock muffler? My field has a sound limit.
Thanks!
01-22-2014, 06:19 PM
#3272
There are no problems with the Fox .15 engines. You do have to run them in some first though. The engines use a lapped piston and steel sleeve though. No ABC.
I never measured the noise levels though, so I cannot comment on that.
I never measured the noise levels though, so I cannot comment on that.
01-22-2014, 10:27 PM
#3273
My first .15 Schnuerle engine was kind of a bear the first couple days. It was so tight, I used a heavy plastic screwdriver handle as a chicken stick. With Red Max Castor.Synthetic blend, 10% nitro, the first 5 or 6 starts got me a single revolution of the prop. After about a week, I was turning an 8-4 wood prop at near 15K. Had about a 1600 idle. Small engines usually don't idle as well as the bigger engines. That engine, always running about 15 to 20% castor in the fuel, is the one that got me over 3000 flights. And, probably because of the castor, when it spent about a week in a puddle filled with acidic drippings from an oak tree, all I had to do was flush it, mount it on a new plane with a new prop and needles, and it was good to go.
Hsukaria, instead of selling that old engine, you might check with Fox. They have, or had, a trade in policy giving up to half off on the price of a Fox engine.
I think that shortly before he died, Duke Fox started stating in the engine instructions that the use of some synthetic oil in the fuel was acceptable, as long as it was still at least 50% castor.
Hsukaria, instead of selling that old engine, you might check with Fox. They have, or had, a trade in policy giving up to half off on the price of a Fox engine.
I think that shortly before he died, Duke Fox started stating in the engine instructions that the use of some synthetic oil in the fuel was acceptable, as long as it was still at least 50% castor.
01-23-2014, 05:39 AM
#3274
You can use all synthetic oil in the Fox ringed engine, though I would recomend some castor oil. My Fox .50 runs fine with 5% Morgans Omega. But the ABC engines need castor, and the lapped engines should use 100% castor. You can get away with a castor synthetic blend in the lapped engines. But it won't have as good of a compression seal, and I suspect they won't last as long. When you lose compression from synthetic oil the blow by will heat the engine and it will run crappy. With a CL plane it will run just enough to stay in the air and any attempt to land will end with a crash landing. But it you wait for it to run out it will be super hot.
01-23-2014, 06:59 AM
#3275
50+, I wasn't planning on selling my Fox engine, I was considering a new 40 size for the future. But the engine I was considering for sale was a Super Tigre G51, but talking to some guys in that forum convinced me to keep it and try to modify it a bit. So, I will keep the Fox 40 in my mind for the future.