S1 Ringmaster

Yup, as others allude, got my first Champion glow plug a year ago as part of a K&B .09 Torpedo purchase:

https://www.coxengineforum.com/t16866-kb-09-torpedo-engine

K&B .09 Torpedo, left side.

Use it or put away for display, you have a collector item bonus with your Fox .35 Stunt engine, @Onelife.

Thanks for all the info and interesting thread on the torpedo. I would like to do some homework on the champion spark plug and I’m going to clean the Fox up and I would like to fire it up without ruining it. Ken got my attention on the hot spray coming from exhaust. Then it’s on the shelf it goes. I didn’t think much about the plugs till you guys brought them up.  I don’t even know where to start to bench run it looks like I’m at the right spot thanks


I see a hemi head by Larry Foster also on eBay
https://www.ebay.com/itm/375330733390?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=yizwsyurrss&sssrc=4429486&ssuid=nKDcgMxXQC2&var=&widget_ver=artemis&media=COPY

Does it look like the connection is bad on this plug

I will say with any engine that your unsure of it's history is to remove the backplate and make certain the rod is traveling freely on the wrist pin. With a Fox this can be a pain in the rear. This engine still uses the brass end pads. I don't typically use all castor fuel in my Fox .35's but these I do because of the brass. Most feel it won't harm the steel liner but it can wear the face of the end pad away. The 50's version Fox .35's have egg shell like cases, it's very easy to distort the case if the head is improperly tightened. Use caution if you remove it. This means criss crossing the screw pattern and tightening while checking for binds. The head will flex due to the fins running fore and aft so be aware of that. There's usually the magic screw which causes the engine to bind when tightened. I've opened that one hole up with a number drill to enable a bit of clearance. Or, I tighten until it's snug and hit it with CA and kicker to retain it.

     Just for those that don't know, Greg from Kamtechnik makes a beautiful backplate for the Fox .35 which utilizes a o-ring vs a gasket. This is a machined piece vs the cast hunk of crap offered from Fox where the ears bend and break. I can't say enough good about it. https://kamtechnik.com/product-category/fox-aftermarket/

        As far as hemi-heads are concerned, I have used and own all of them. Some are good, some are ok . Some claim the hemi head offers more power. I've never found that to be the issue. It certainly changes the run and it supposedly takes away that drowning transition when the engine goes from right side up to inverted. Jim Lee purchased the tooling from Tom Muggleton who introduced the Blue Magic Hemi Head years back. Jim makes this head now and I recently purchased one which I haven't tried yet. The head is no longer blue anodized like Tom offered but rather mill finish aluminum. Some have claimed the hemi head offers more power. I don't know as to why that would be, the combustion chamber is now taller so in my opinion it's more volume and less compression. The Fox hemi head uses a head button which needs to be indexed correctly or you will break the baffle off of the piston. You have limited tolerances as to rotating the head button.

I was wondering why the clip went to a Buster Hummm Now I know , I just am not good a recognizing the different planes !?!? I do like the paint scheme pops right out at ya . Hope you can get the holes and engine placement so it will bee good to fly .

Sorry about turning this thread into a thousand different subjects but I sure do appreciate the help I receive thanks for putting up with me.
Hole placement like all the other profiles I built don’t offer much room (material) on top leg i plane on using a aluminum shim instead of directly mounting it to plane.
Ken I  will take of the back plate and hopefully the piston moves freely on the eye pin I hope. And I do try to take care when putting head back on by that alternating the screw pattern but I sure wish I had your feel and what to look for when it comes to putting them back together.
What do you feel for when checking if the engine moves better, How do you ever find that one screw ? You said something one time about tightening the head and I told myself that’s something I will remember but I forgot. It went something like tighten the head to the shims not to the body I forgot. ????I wish I had that skill. I’m sure doing it wrong could lead to some bad vibration at the lest. Ken what brass tabs are you referring too please? I love it when you guys go into detail I always learn something and I’m that much more aware when I tear a engine apart  I found out most of the time that’s the easy part putting it back together is the hard part. Thanks again

The Fox you purchased has the raised circular area with 35 cast on it on the bypass. The next generation Fox did away with the circular area and the 35 designation. At this point, Duke transitioned from using brass eyelets on the ends of the wrist pin to using circlips to retain the wrist pin. While I like having the circlips due to eliminating wear on the liner from fore and aft movement the circlips can come out. When a circlip drops out, it's game over for the Fox. I've lost at least 6 engines due to this happening. I make absolutely certain that the clip is fully engaged and I also make the center portion of the clip vertical so that any movement in the up or down direction won't disengage the clip.

When checking a engine for a bind, you must remove all oil and carbon deposits from the liner . I do this with fine steel wool and penetrating oil and thoroughly clean. The glow plug is removed from the engine when doing this. Rotate the engine and note if there's a pinch in the assembly. Generally, you can feel a pinch at or around the exhaust cutout due to the caveman like tools used to make the liner. I turn the piston upside down and use Brasso to lap this area with the bottom of the piston skirt. Clean and reinstall piston right side up and this can alleviate the pinch at that area. However if the piston gets tight up top, loosen all head screws and check again. This is where you can find that one or two screws that are problematic.

I prefer to lap the top of the liner on a piece of glass with 400 paper and oil. I also have a tool that fits into the case snugly which I glue a piece of paper on so that when I rotate the tool it trues the top of the case to the centerline of the piston. What my tool doesn't account for is if the centerline of piston is square to the crank which is anybody's guess.

I only clean up any area just enough to insure clean flat sanding marks all the way across the surface. The next thing that I sometimes have to do is sand down the bottom of the cylinder head. Around the bottom of the head are a few circular marks which are where the ejection pins removed the heads from their molds. I sand the bottom of the head to insure that the head doesn't bottom out to the case. In other words, I want to make certain I'm tightening the head to the liner and not to the case.

Now when tightening the head, I keep checking for binds and loosening one screw at a time if I discover one. There's no magic feel here, it either binds slightly or it feels smooth 360 deg through rotation. When I have the engine where I want it. I put light machine oil in it. With a prop on it, the prop should fall on it's own weight to BDC when the prop is clocked horizontally. I want to insure it's totally free on the bottom end of things.

While none of this matters to most, I've found that I can get the Fox to run very strong and continuously lean if I find the need to do so such as in racing events. The problem with doing all this is that in order for the engine to retain it's longevity is not to run it. Just run it when you need to. However, simple things can be done to one's daily runners to improve on things.

I always say this, if one really wants to find out if their Fox .35 is truly broken in, bolt it on a Bi-Slob. When prop hanging a Bi-Slob, the engine breaks lean and continues to run in this mode only if it's broken in. I have seen many do this, the engine sags and stops and the Bi-Slob crashes it's tail into the ground obliterating the plane.

Man Ken thanks like I said before your knowledge on the Fox is outstanding holy smokes Man I’m lost for words. You nailed it tighten the head to the liner not the case. I look back on all the Fox 35 I took apart and put back together and feel it was all a waste of time because I didn’t do it right but they ran afterwards I guess I can be happy with that , man I would love to have you tune a engine up in front of me that would be a treat. You mentioned about losing a circlip and game over I rarely took off the piston from wrist pin but now I’m curious on what they look like hard to see inside the piston.
I’m going to start with the basic and check on the stamp 35 on the bypass and see what I have.
What is a Bi-slob ?

I don’t see any clips or elelets must they be bought separately?

The best advice for a Fox .35 is to not take it apart unless absolutely necessary. I scribe a line on the cylinder and the case to align it prior to taking it apart. Even if your off a little, it's really not lined up like it was prior to taking it apart. Unlike a OS engine, there's no roll pin to index the cylinder in the case or to prevent it from rotating when tightening.

       As one starts flying more maneuvers and consecutive maneuvers, the demand for engine performance increases dramatically. While some will say run a 10x6 prop on a Fox.35, I WOULD NEVER recommend this today. There was a time I would but unfortunately, it taxi's the engine far too much for the style of flying I do. Even planes such as the Geiseke Nobler would recommend a 10x5 wood . The engine is in 4th gear running a 10x6, when you need to climb and the power to go up, you no longer have it once you bled off the speed. At least with a 10x5, it enables the plane to still drive even though it's struggling. My go to prop is the Master Airscrew 9.5x6 and I use this on every plane I have under a 48" wingspan. Larger planes, I go to the APC 10x5, it's weight and load works exceptionally well on the Fox .35 providing a decent load and a harmonic balance effect. To complicate things further, when you muffle the Fox .35, it just totally overheats the engine. I can do it because our field requirements demand a muffler. Without doing some of the things I do them, I'm not able to satisfactorily obtain a good consistent engine run using a muffler.

       The Bi-Slob is a biplane which has the ability to hover so to speak. Here's one video of my son flying at Brodak's https://www.youtube.com/watch?v=VtQ6m-DP7G8
I've built several, all of them with the same color scheme. Blue wings, white fuse and red rudder. Neal who is listed as one of the flyers was a 911 firefighter. All of Neal's planes are usually red. At 4 min and 29 seconds Dan is hanging his Bi-Slob. This is where you will ultimately know that your engine is broken in as these are running mufflers as well.

Bi -slob I seen RC videos of it but never new the name and that’s the first I seen CL slobbing I’m definitely going to have to find another way to tell if my engine is broken in lol.
Thanks for all the tips again Ken Thanks for sharing video.

First coat of clear

Your model is looking good, @Onelife . Curious cat reminds me of our cats 30 years ago. When we moved, we became catless. Found that my son was highly allergic to them.

Thanks yes I have 3. They all have thereown personality’s thanks again.
I ruined almost a whole qt of clear I had enough mixed up about 2 cup fulls for spray gun ahead of time because I’m using Brodak clear and Wicks thinner I wanted to see if it mixed well and
Dryer. So I went to mix more and my clear had a pink shade to it. I think I cleaned a small touch up bruse in my clear thinking it was my thunder I honestly don’t know what happened I just know I need more clear now and more money. 1 coat isn’t going to cut the cake

For that exact reason, I don't want cross contamination and I have a gun for clear only and color with the other. Generally, when I spray a clear coat, I spray it and let it tack up for 10 minutes. I come back and spray again. On my final passes, I go over all leading edges because this is what sands off the easiest and fastest when I knock it down for next coat. When spraying the leading edges of stab and wing, the excess blows over the top and doesn't offer a wet look. I don't concern myself with that. I go over every rib on the wing front to back, back to front and build up the clear on the rib top. I do this because that's where your going to sand through. Every time I coat, I go over the ribs and anywhere that generally sands off quickly. This usually equates to radius edges especially on a profile. Keep building up those areas. Don't rub these areas with folded sandpaper in your hand. You go in one direction and one clean pass otherwise your removing material that you really need to stay. Sand with fine grit paper, I usually have a wide assortment of 600-800-1000-1500. Keep this paper wet in a bucket of soapy water prior to using for at least 15 minutes. I basically have 5-6 coats when done.

Hey Ken yea thanks for the pointers , the leading edge I fine you can get a real nice glaze finish on it. I don’t know how I got red in a full can of clear. I think I must have thought it was thinner and cleaned a touch up brush in it. That’s upsetting I can still use it on sealing silkspan or the body not all wasted but I can’t finish it now. I wanted 3 coats. Have you ever tryed the 3M finishing pads ?

I never used that 3M product. I use a old sock lots of elbow grease and Brasso metal polish when I'm done. Archaic but effective.

Ok ,

I cheated on my design don’t tell anyone. I got my ideal from here
https://youtu.be/ftFZLlawDUc?si=buMlPFRdF61Pl3nt
It’s the music video (tribute to the fox 35 stunt

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Easy peazy.

Bob Geiseke's Nobler shown in this picture is currently and maybe already restored. It was discovered about a year ago and all the covering was split.

Cool trivia thanks. Love that video