Thanks for the photos, John. That is certainly a novel arrangement. I suspect there must be another spring to hold the points open, until it's overcome by the cam and coil spring. Is that a leaf spring or lever that I see in the second photo, alongside the point arm? If there wasn't a spring to keep the points open I fear they would bounce closed and open at all the wrong times.

I don't know if it's available in UK, John, but we've found a new product for cleaning old engines, and it really works! It's supposed to be for removing baked-on grease from baking dishes, pots and pans, etc., but it works wonders for old engines. You can brush it on the exterior so long as you keep it out of the intake and exhaust. It's made by Proctor and Gamble (PG), and it's called "Dawn Power Dissolver." I found a Dawn company online that makes industrial products, including soap, but that's not the right "Dawn."

It's available here in the supermarkets, on the shelf with laundry soap, etc. I had my wife pick up a spray bottle of it, but I haven't tried it yet. They say the best way is to dissemble the engine and put only the crankcase, cylinder head, muffler, etc., in a sealed plastic bag overnite, after spraying with this product. You don't even have to scrub it. Next morning it's looking like new after a rinse in tap water and dried with a clean shop cloth. I have an old Fox .40 glow engine that needs cleaning before going into a sorta-scale cabin monoplane, so I'll be trying it out soon.

Hi Gord; Most of the push mowers I've seen have two-stroke engines, similar to leaf-blowers and week-wackers. Are the four-strokes you're referring to light enough for (large) model airplane use?

No, these are vertical shaft engines with an oil sump.

I haven't seen that type, but I haven't been paying much attention to lawn mowers since I moved to Arizona (no grass!).

But you're right about a plug firing on the exhaust stroke (having no effect, since there's nothing left to ignite). That's the way modern electronic ignition systems work on four-strokes, even on two cylinder ones.

Don, did we manage to discourage you from trying gasoline?

Hi again,

I spent some time racking my brain over the issue of gasoline or methanol fuels. I had in the back of my mind that someone of modelling stature had done some work on the subject.
I have at last remembered the name, Maynard Hill (Hall of Fame etc). He set up altitude and duration records and I found a reference to an article about him.

Glow or Spark Ignition

Model Airplane News article about fuel & ignition systems for duration.

3. “Beat the Russians or Bust – Part II� MA, August 1965, p. 25, Vol. LXXII This lengthy article discusses a duration world records of 8 hours and 52 minutes set on September 18, 1964. Trade-offs about diesels, glow and spark ignition are explained. Tank systems, special glow plugs, fuel consumption measurements, reason for five failures and description of successful flights are included.

I haven't found the article itself but only the reference as mentioned above.

In a previous post I mentioned the Arden ignition engine I was given. I found it was in fact a Micro-Dyne Atom .09 circa 1944. It has no needle valve just a fixed fuel jet. The air intake is through the exhaust port via a "valve in piston" system. The mixture strength is controlled by a sleeve valve (below the c/case) that is turned to control the air volume. The more I consider it, the lass likely I am the use it in a model that I expect to fly.




old git - - - - - - -aka John L.

Here's a lengthly article from Model Aviation about Maynard Hill and his efforts with OS60FS engines on ignition.

http://www.modelaircraft.org/mag/mhill/hillindex.htm

Thanks for the link, W8YE. Back in the early '90s I assisted Jim Kelley in running a Saito 52 on gasoline, with which our team won the first and third running of the California R/C Marathon.

No doubt gasoline is the fuel to use for the best milage per unit volume. Several teams tried diesel, but none would keep running continuously for five or six hours.

Thanks for the ref for the Maynard Hill article, makes me happy I am not further down the hill into decrepitude. I was aware of the record flight but had only seen a very short article.

By the way, the motor he mentions is a VINTAGE OS FS-61. I expected to see mention of the OS FS-60, I tried to buy a magneto for one on eBay, I missed it, fell asleep but maybe I couldn't afford it anyway.To me the 61 is a new motor, not vintage. During my search I came across his "Electrostatic Autopilot" in Radio Control Manual No 5 (probably late 70s). The model was able to follow the contour of the electrostatic charge in the atmosphere. It uses Polonium sources at the wingtips and on the top of the vertical staibliser.

You may have read that a Rusian was poisoned in London using Polonium, made me think of the Maynard Hill exeriments.




old git - - - - - -aka John L.

Have any of you guys ever tried the GAS/GLOW mix on your glow engines??? a friend of mine has tried it on an O.S. 40 using 33% methanol, 66% 91 octane gasoline after mixing this combination he then made a 10% amzoil oil fuel (90% fuel mixture with 10% amzoil) and we were impressed with the the way the little engine runs, so I know it could work on bigger glow engines like the supertigre series or the mokis, I know that morgan fuels makes a special blend of glow fuel for the supertigres that only contains about 5 to 6 percent oil, so that tells me that 10% or even less oil should be enough for the GAS/GLOW fuel mix to be run on glow engines, also we need to take into consideration that gasoline has some lubricity by itself compared to methanol that has none (dry).
So give it a thought, this fuel mix is being used on weedwacker conversion engines with great results at a much lower oil concentration (3%) because they have needle bearings and can run with less oil.

I was wrong about the engine. He had the old 61's like is pointed out above and not the 60 I mentioned.

Hi Aeronut; Since gasoline produces more heat than alcohol, you need a larger percentage of oil for converted glow engines than for engines designed to run on gasoline, such as the weed-wacker derivitives, partly because, as you mentioned, the latter have roller bearings on the rod end, while glow engines have plain bearings, with the Aluminum rod turning against a steel crankpin. (Larger glow engines have a bronze bearing inserted in the rod).

Also, engines designed to run on gasoline are made heavier than glow engines, with more metal and larger fins for cooling. Be sure to allow plenty of airflow past a glow engine running on gasoline. If it's cowled, the air exit should be at least twice the area of the inlet, and three times as large is better.

We found that "regular" pump gas or Coleman stove fuel ("white" gasoline) mixed with 10 - 12% "Red Line" brand motorcycle racing oil worked best. We tried Klotz and other oils, but Red Line would leave a piston absolutely clean after four or five hours running. You can't do that with castor oil!

W8YE; That's a real pretty Aeronca "Champ" in your avetar. Is it full-scale, or smaller? I flew one of them when it was brand new. Can you guess what year that was?

If it was a 7AC the year was 1946.

We had two like this, same color and everything, full scale (the picture is from the internet) at our airport in Auburn, Alabama. I soloed one of them in 1964. To make a long story short, I later got my flight instructor's rating in a 1957 7EC Champ. Besides having a bunch of time in a 90 hp Reed Clipped Wing J-3, I really enjoyed the Champs both 65 and 95 hp.

I've been around several glow fueled four strokes both OS and Saito in recent years that had C-H ignition on them. They ran perfect and would idle really low all day.

Actually, it was 1947. My summer job in high-school was 1/2 of "the apron crew" at Marion Airport (Marion, IN). Two of us drove a Crosley-powered gas truck, with which we fueled visiting aircraft, handled parking and tie-down, chocks & props, drove a tractor to mow the (grass) runways. Nowadays a 15-yr old kid would not be allowed such a "dangerous" job. One of the perqs was, we got to fly any of the company aircraft, paying only for the fuel. In '47 we got three 7ACs to replace some aging J-3s in the flight-training program.

I did the same thing in the early 60's

Running gasoline in a glow fuel carb..... The needle is so sensitive you can never seem to get it set right?

You got that right! We tuned for full throttle and never backed off. The airplane was designed to average 50 mph at full throttle. We also tried using smaller carbs in our tests of 2-stroke glow engines burning gasoline. The 2-strokes were never as reliable as the four-strokes, and harder to tune. We used Al Diem's "Silent Spark" solid-state ignition systems in our marathon winning airplanes.

Ralph Morris,

I have been reading your posts about the Duration Event a few years ago with interest. The reason is that I am planning a 264 mile flight from the Texas-Mexican Border (McAllen, TX) to San Antonio Texas in April of 2009. We have a straight Hiway on a North-South line with just three towns that make you slow down to 30 mph. Also during the Spring there will be a tailwind from the South of 12 to 20 MPH.

Two weeks ago John Worth (AMA) e-mailed Maynard Hill's e-mail address to me and suggested I talk to Mr. Hill about his engine.fuel set up. I called and found that Maynard Hill is going blind. Also I found that there is an article in the January 2004 Model Airplane News tht has photos and text about the power unit.

Also Maynard told me he is working with a OS FS-52 4-stroke to attempt another flight in the coming months. I am guessing this one will be over land. He wanted me to read the MAN article first before we talked about the carb & engine. He said he used a carb from an O.S. 10 RC engine on his 60 4-stroke and he had a 4 inch piece of "Tygon" to attach it.

Ralph, I am asking you "How would you attach a smaller carb using Tygon to a Saito 56 4-stroke.?"

Question 2 . Where did you get your Hall's Effect unit? Any info on the senser ,etc, would be appreciated. THANKS.

You could start with CH Ignitions http://www.ch-ignitions.com/ Good Luck, Capt,n

Exporter; Thanks for reminding me of this thread, which I enjoyed reading again, also.

I believe the tygon (clear plastic tubing) was attached to the carburetor intake, to damp any turbulence before the inlet. We also tried this on the two-strokes using a smaller carb and running on gasoline.

You have to improvise the attachment of a smaller carb to the engine. We machined an adapter in one case, just a flat piece of Aluminum drilled to fit the smaller carb, with slots for the engine bolts. That was to mount the smallest Walbro carb on an OS 60 two-stroke.

NOTE: I have one used and one NIB Walbro carb, if anyone needs the smallest one they make. Best way to go for a small two-stroke on gasoline. This carb would work for .60 to 1.60 two-strokes. I also have the OS 60 two-stroke, with the head drilled and tapped for a larger spark plug. Bench run only. Also one Al Diem "Silent Spark" electronic ignition system. Make offer.

We only tried using smaller carbs on two strokes. The Saito 52 four stroke that we won the marathon with (twice!) used the standard carb. We set the mixture for full throttle and never throttled back, because that often caused the engine to quit during our bench testing.

As a result, we had to fly a circle once or twice on the downwind legs in order to avoid exceeding the 55 mph average (which we could see on the car's speedometer). We had tested the airplane/engine combo and determined that it would average just over 50 mph at full throttle. If you averaged over 55 mph between any one of the 10-mile checkpoints, you got penalized. They had a pretty elaborate timing crew who noted the exact time when the checkpoints called your number, and then calculated your average speed during the previous 10 miles. Some were penalized for going too fast, but they didn't last long enough to be competitive.

One fo my favorite engines was a Saito .56 High Cam. It was real good on fuel and ran perfect. I wish I never had sold it, I had the engine from day one. I broke it in carefull and took very good care of it. Capt,n

John; I feel your grief for allowing a fine engine like that to get away from you. One of my favorite engines is a Fox .40 that Duke Fox gave to my son, sometime in the early '80s when the MAC Show was held in Pasadena, California. It's had new bearings since then, and it still has good compression. I have an old cabin monoplane to put it in next. It flew in my Midwest "Sweet Stick" in the mid-'80s, and it's been on the shelf ever since I changed it for a Fox .50 in the Stick.

Ralph. I can see why you would want to hold on to that Fox .40. Getting it fom the "Duke" himself, is really neat in itself. Wow! I had a Fox engine gave to me, and it had super good compression. It was a rear exhaust engine and had a kinda strange muffler on it, like a elongated box! Anyway I found out with the sloppy worn out carb on it, she did not behave very well. I placed a Perry carb on it....boy did that engine come to life! We used it on a Kadet float plane for quite some time. Thats another thing...I gotta do a float plane again. I used to fly off Muskegon River which was kinda narrow for take off. With the current it was a challange! Landings was a piece of cake. Best Regards Capt,n John

Ralph Morris,
You posted this, "NOTE: I have one used and one NIB Walbro carb, if anyone needs the smallest one they make. Best way to go for a small two-stroke on gasoline. This carb would work for .60 to 1.60 two-strokes. I also have the OS 60 two-stroke, with the head drilled and tapped for a larger spark plug. Bench run only. Also one Al Diem "Silent Spark" electronic ignition system. Make offer."

You spoke of the NIB Walboro carb. You say it would work on a 0.60 to 1.60 two-stroke.
Is there a reason why the NIB Walboro carb would not work O.K. on a 0.56 4-stroke ? I can see if the carb is using crankcase pressures it would pump in fuel on the exhaust stroke - maybe that would make the mixture too rich.......is that it? But in my weed
whacker with a 25 cc Two Stroke (Homelite) the carb is a Walboro.....and it runs like a top. So I need some education.

Purchase: The NIB Walboro carb might be interesting. What it's worth is a mystery to me. I would guess that it's worth somewhere between $20 and #35.00. HOW did you mount it......can it be mounted on a piece of Tygon?

That Al Diem "Silent Spark" electronic ignition system is unknown to me. I just know some about the C & H Ignition. Tell me about the Al Diem system
My e-mail is [email protected] Maybe that would be better. Fell free to use that address.

I bought a Fox 0.40 and flew it for several months on a Midwest "Sweet Stick" ( Lotsa Phun !) Well one dau when landing a bit hot I overshot and ran into the trailer hitch mounted on a Ford Car. It sorta squashed the cylinder.....piston was really tight. Got a new cylinder and piston - re broke it in on Duke's Mixture....( the one with lots of castor oil) and flew it periodically for years... it sits here ready to go anytime. That Fox 0.40 IS a good engine!

Capt,n john here! It was not I that talked about the small Wabro carburator. The use of a Walbro carb on your 4 stoke engine may be a nitemare. I am not saying it cannot be done. Just what is the reason you want to try the Wabro? If it is to strech out the flight? Maybe a small Suoertiger Carb off a X11 would work or any .10 size glow engine. Best regards capt,n

This is not a reply...just another Idea. If I was going for a long distance run, I would place main fuel tank on C.G. Then use a small 2 oz hopper tank close to engine for consistant running. A pressure line from muffler or crankcase would pressurize main tank and shove fuel to small hopper tank. Then use a small carb off a .10 glow engine. Also it looks like Saito is going to have a smaller size ignition engine which may have great potential! Best regards, Capt,n

Interesting thread, but SAITO (both FG36 and 20 GAS engines) have the connecting rod without needle bearings, The FG 36, does not have plain bronze bushing on connecting rod at piston side. Directly the aluminium with only one oil hole, and bronze bushing on crankshaft side. No wear on con-rod at 20:1 oil (break-in) or 33:1 (after break-in).
I'm testing a 140 glow engine converted to ignition, running petrol, and also no wear on bushings at 5% oil (motul 800) after 8 liters (maybe 2 gal. ?) . Performs awesome, starts at first-second flip, idle is low and steady, ...... The major problem was the muffler pressure tap, and melted tygon tube, until i replace by neoprene tube.
I've tested a perry gas pump, but at lower pressure level it pumps too much fuel. Also i've made some minors changes to the engine in order to lower compression ratio, needles adjust , enlarge the oil holes on connecting rod, etc.


Regards