Club FOX!
09-30-2016, 10:27 AM
#4801
Most modern .15 engines will spin an 8x4 at around 15000rpm, and that is also what Fox promises that the engine should do.
As a comparison, a Cox Conquest RC (with stock muffler) will spin the same prop at around 16600rpm
As a comparison, a Cox Conquest RC (with stock muffler) will spin the same prop at around 16600rpm
09-30-2016, 12:01 PM
#4802
But isn't the Cox Conquest a heavy engine compared to most 15 size engines? How does a Fox 15 compare to an average 15 size engine?
09-30-2016, 12:44 PM
#4803
Here are some engine weights of ballbearing .15 RC engines (without mufflers for a fair comparison of the engines themselves) ;
Norvel .15 BB; 152g
ASP .15XLS; 168g
MDS .18 BB; 172g
Fox .15 BB; 180g
Cox Conquest; 180g
Norvel .15 BB; 152g
ASP .15XLS; 168g
MDS .18 BB; 172g
Fox .15 BB; 180g
Cox Conquest; 180g
Last edited by Mr Cox; 09-30-2016 at 12:49 PM.
09-30-2016, 01:12 PM
#4804
I have the Norvel engine both BBC and bushing. Have not used them yet, but their mufflers are relatively large. They look like they are tuned mufflers for enhanced performance.
09-30-2016, 07:36 PM
#4806
Senior Member
Ihave bb norvel .15 and .25 idont like it, not any good revs.
My latest combat engine is fora.21 from ukraina apc 9x4 10% nitro 15400rpm
Icant test fly it because ihave hand injury
My latest combat engine is fora.21 from ukraina apc 9x4 10% nitro 15400rpm
Icant test fly it because ihave hand injury
09-30-2016, 07:55 PM
#4807
I have 4 Enya 15IV engines (old baffled Meehanite piston).. Last one I ran did 15,900rpm on a 7x5 MA Scimitar on 10% nitro. They really come alive on 15-20% nitro though.
09-30-2016, 09:11 PM
#4808
Sorry about your finger, by the way, it looks gruesome.
09-30-2016, 10:35 PM
#4809
The Norvel .15BB is a hidden treasure... 
The stock carbs a little restrictive, that gives a very low and stable idle (around 2500rpm) but limits the high end a little. The remedy is to put in an MVVS .15 carb instead (a direct drop in) these engines will then do 15800rpm on the APC 8x4 (and 10% nitro). Together with their low weight and low fuel consumption it is truly a great engine.
The stock carbs a little restrictive, that gives a very low and stable idle (around 2500rpm) but limits the high end a little. The remedy is to put in an MVVS .15 carb instead (a direct drop in) these engines will then do 15800rpm on the APC 8x4 (and 10% nitro). Together with their low weight and low fuel consumption it is truly a great engine.
09-30-2016, 10:38 PM
#4810
I have one ASP .15XLS (blue head) that was a little stiff in the bearings at first but it now makes about 15000rpm on an APC 8x4 and 18500rpm on an APC 7x5. A usual nowdays(?) the problem lies in the quality controll rather than in the inherent design. A second engine leaked between the liner and crankcase...
Last edited by Mr Cox; 09-30-2016 at 10:41 PM.
10-01-2016, 04:09 AM
#4811
I also have a new AP Yellow Jacket 15 that I have to break in. It is weaker than the average 15 but smaller and lighter. Quite inexpensive, but cute.
I suppose all these small engines require some castor in the fuel?
I suppose all these small engines require some castor in the fuel?
10-01-2016, 08:12 AM
#4813
I disagree most will spin 15,000 my TT only spins about 14,000 and I think the LA is the only current engine and it spins the same as TT.
10-01-2016, 06:14 PM
#4814
I tested a whole bunch of .15s, and found the T Tiger about the bottom of the pack, the LA in the high middle, and the blue head ASP about the same. I used a 7-5 MA prop, 10% and no muffler to be fair. The Norvels were very good with a bigger carb, and the muffler is not really tuned AFAIK. It has a small outlet, and a big baffle (which I removed) I have a BB one and a sleeved Big Mig. The Fox BB .15 was a bit under the middle of the pack but pretty good overall. I think an 8-4 may be a bit slower than a 7-5, but mine were mostly in the 17,000 range with the Fora, Taipan and Conquest over 20,000. The blue head ASP is up there too with a new Turbo head. From what I remember, a bigger carb on an LA gives little gain, but opening the muffler helped a bit. No muffler is best if you can get away with it. Sorry about that finger Sarpet. A friend of mine got his arm chopped up pretty bad when it got away on him. Ouch, be careful Safety forced.
Last edited by aspeed; 10-01-2016 at 06:16 PM.
10-02-2016, 02:11 AM
#4815
Senior Member
Today irun this little engin very hard," missile mist" fuel 25% castor and 25% nitro, nice weather, no wind and sun shine.
Good sunday morning for high nitro castor fuel and exhaust gasses smells good, with synthetic oils gasses smells so bad.
Best plug with missile is normal medium, itry fox short idlebar and enya3.
China apc 8x4 14900rpm
Jxf 7x5 16700rpm
Apc 8x3.75 15900rpm
Ma 8x5 13400rpm
Ma scimitar 14500rpm
Ma8x3 17800rpm
This is very nice running engine very smooth, easy start, every start with couple flips of prop.
Good sunday morning for high nitro castor fuel and exhaust gasses smells good, with synthetic oils gasses smells so bad.
Best plug with missile is normal medium, itry fox short idlebar and enya3.
China apc 8x4 14900rpm
Jxf 7x5 16700rpm
Apc 8x3.75 15900rpm
Ma 8x5 13400rpm
Ma scimitar 14500rpm
Ma8x3 17800rpm
This is very nice running engine very smooth, easy start, every start with couple flips of prop.
10-06-2016, 01:44 PM
#4818
Anyone want a Fox .50 with some spare parts? I have a few different head buttons that can go with it. It's in decent shape albeit dirty. Turns an 11x6 MAS at 12,700 on 5/20 fuel. Has an MkX-C (.330") carb.
10-07-2016, 03:10 AM
#4820
I got it used from another guy because my other .50 crapped out. It looks like it's got some runtime on it, but it's got good compression and hand starts pretty well. If you PM me your email address, I can send you some photos. It's dirty right now, but I could clean it up for you if you're really interested.
10-07-2016, 03:46 AM
#4821
I spent some time last night putting the FrankenFox back together. I have photos and info a ways back in this thread about it. In a nutshell, this engine had a worn out liner and lost compression. I couldn't find parts for awhile, so my buddy and I had a bright idea to take two junk engines and try making one runner from the two. The donor piston and liner (ABC) came from a crashed MDS .40 with some 10-12 gallons through it. We drilled the piston out to take the Fox wristpin and made our own wristpin of the proper length and used the Fox .50 rod. My buddy didn't have a tool to cut a circlip groove, so we got "creative" and came up with our own wristpin retainer. A single coil from an extension spring. We shimmed the liner to fit the case snugly using a piece of Guinness beer can and put it together. The engine ran well but not all that powerful - a bit over 12k on a 10x6 APC and 10% nitro. The liner was too high in the case, so we milled the deck down .020". This took the head spacing from .036" down to .016" using the MDS cylinder head. The engine then ran 12,600 or so on the same 10x6 and 25% nitro fuel.
Fast forward two years... I noted the boost port in the liner was blocked by the crankcase port runner - almost half the boost port was blocked. So I ground the case to unshroud the boost port some. It's not perfect - there isn't a lot of meat in the case, so I couldn't take as much off as I wanted to without cutting through the case. I also replaced the spring coil wristpin retainer with an E-clip, and I fitted a new head button to use the Fox head clamp. Head spacing is now .011". I'll try running the engine later today to see if any of the modifications made any difference in power. FWIW, the bore is now .828" and .790" stroke making it a .425ci engine. I doubt it's gonna make much more power - my guess is it'll make less power but I'll find out later and take a video.
Some people will probably chastise me for what we did to this engine, but it was an experiment on an engine I had nothing to lose on except $55 I paid for it originally. It was a fun experiment and the engine runs AND didn't eat itself, so it's not all bad.
The purists will hate me... That's okay - I don't mind.
Fast forward two years... I noted the boost port in the liner was blocked by the crankcase port runner - almost half the boost port was blocked. So I ground the case to unshroud the boost port some. It's not perfect - there isn't a lot of meat in the case, so I couldn't take as much off as I wanted to without cutting through the case. I also replaced the spring coil wristpin retainer with an E-clip, and I fitted a new head button to use the Fox head clamp. Head spacing is now .011". I'll try running the engine later today to see if any of the modifications made any difference in power. FWIW, the bore is now .828" and .790" stroke making it a .425ci engine. I doubt it's gonna make much more power - my guess is it'll make less power but I'll find out later and take a video.
Some people will probably chastise me for what we did to this engine, but it was an experiment on an engine I had nothing to lose on except $55 I paid for it originally. It was a fun experiment and the engine runs AND didn't eat itself, so it's not all bad.
The purists will hate me... That's okay - I don't mind.
Last edited by 1QwkSport2.5r; 10-07-2016 at 03:48 AM.
10-11-2016, 04:35 PM
#4823
I spent some time last night putting the FrankenFox back together. I have photos and info a ways back in this thread about it. In a nutshell, this engine had a worn out liner and lost compression. I couldn't find parts for awhile, so my buddy and I had a bright idea to take two junk engines and try making one runner from the two. The donor piston and liner (ABC) came from a crashed MDS .40 with some 10-12 gallons through it. We drilled the piston out to take the Fox wristpin and made our own wristpin of the proper length and used the Fox .50 rod. My buddy didn't have a tool to cut a circlip groove, so we got "creative" and came up with our own wristpin retainer. A single coil from an extension spring. We shimmed the liner to fit the case snugly using a piece of Guinness beer can and put it together. The engine ran well but not all that powerful - a bit over 12k on a 10x6 APC and 10% nitro. The liner was too high in the case, so we milled the deck down .020". This took the head spacing from .036" down to .016" using the MDS cylinder head. The engine then ran 12,600 or so on the same 10x6 and 25% nitro fuel.
Fast forward two years... I noted the boost port in the liner was blocked by the crankcase port runner - almost half the boost port was blocked. So I ground the case to unshroud the boost port some. It's not perfect - there isn't a lot of meat in the case, so I couldn't take as much off as I wanted to without cutting through the case. I also replaced the spring coil wristpin retainer with an E-clip, and I fitted a new head button to use the Fox head clamp. Head spacing is now .011". I'll try running the engine later today to see if any of the modifications made any difference in power. FWIW, the bore is now .828" and .790" stroke making it a .425ci engine. I doubt it's gonna make much more power - my guess is it'll make less power but I'll find out later and take a video.
Some people will probably chastise me for what we did to this engine, but it was an experiment on an engine I had nothing to lose on except $55 I paid for it originally. It was a fun experiment and the engine runs AND didn't eat itself, so it's not all bad.
The purists will hate me... That's okay - I don't mind.
Fast forward two years... I noted the boost port in the liner was blocked by the crankcase port runner - almost half the boost port was blocked. So I ground the case to unshroud the boost port some. It's not perfect - there isn't a lot of meat in the case, so I couldn't take as much off as I wanted to without cutting through the case. I also replaced the spring coil wristpin retainer with an E-clip, and I fitted a new head button to use the Fox head clamp. Head spacing is now .011". I'll try running the engine later today to see if any of the modifications made any difference in power. FWIW, the bore is now .828" and .790" stroke making it a .425ci engine. I doubt it's gonna make much more power - my guess is it'll make less power but I'll find out later and take a video.
Some people will probably chastise me for what we did to this engine, but it was an experiment on an engine I had nothing to lose on except $55 I paid for it originally. It was a fun experiment and the engine runs AND didn't eat itself, so it's not all bad.
The purists will hate me... That's okay - I don't mind.
10-11-2016, 05:08 PM
#4824
Yeah... Epic FAIL. The muffler screw hole on the side of the case that was damaged stripped out using the MVVS muffler and I forgot where I put my Davis Soundmaster strap-on muffler, so I didn't get a good run in on it. I had a 9x6 on it and got over 13k from it before the muffler screw let loose and the rpm dropped. So I need to get it back on the stand with the Davis muffler and give it another go. I probably need to put the smaller carb on it too. A .330" carb is a bit much for a .40. I also think I need to adjust the port timing a bit - I'll need to degree it before I mess with that though. It's a solid runner despite not being super powerful. It hand starts easily and idles all day at 2,200rpm with a 9x6 and 5% nitro!
10-11-2016, 05:14 PM
#4825
My .50 Davis Diesel head is either gonna go up for sale or get milled to fit my .46. I traded my other good .50. I've sold or traded most of my ringed engines as I don't feel they run near as well as diesel conversions as ringless engines do. I've never liked my ringed engines on diesel from the get-go. My SuperTigre 45 diesel is a total rockstar and next spring when I get my K&B Sportster .45 broken in I'll have my two rockstar .45 sized diesels up and running. K&B and ST have been much more solid engines for me than any of the Foxes I've had. If I can dieselize my Fox .45, I will and I'll keep it around. For now it's gonna stay a drawer ornament..