Spark Ignition Conversion

[Garf]

I want to play with a spark ignition engine on a C/L model. I have been trolling for a Madewell 49 on Ebay with little luck. I have a lot of glow engines, but I don't know if they will survive running on gasoline. What type of engine would do best on gasoline?

[Randy Ryan]

Actually you could run FAI fuel and nearly anything would be OK. SAM has approved its use, but I don't know about OTS even if there's a body that would interpret. I don't remember reading anything inthe rules about fule restrictions. The FAI fule runs cooler and gernerally starts better, just remember to use castor if you convert an iron/steel engine.

[Garf]

The idea is to use a gas/oil mix. How would an ABC engine do on that mix?

[Jim Kraft]

It would probably work OK Phil. It would not be worth any points in old time as they do not give points except for original ign. engines. Before they made this ruling, Don Hutchinson converted an OS 40 FP (I think) to spark, and as I remember it ran very well. I do not know what he was running for fuel though. If I was to convert a glow motor to run on gasoline, I would mix it with castor instead of 70 wt. oil. This works fine in most areas of the country I think. If you find that the castor does not stay mixed, just add a little glow fuel, and it should mix right up.

There are a lot of good sparkers on E-Bay right now, and some are going for very good prices for buyers. The only thing bad about that is now you have to set up a Pay Pal account to buy anything. I am glad I bought the engines I did before that change. I have purchased 3 engines from there at very low prices. The 2 Spitfires were both brand new, had never been run or mounted, and an Orwick 64 that was in super shape.

Oh! Bill Schmidt had an article in Stunt News a few years back for converting a Fox 35 to spark. He had a plan for making a timer for it using McCoy points, but I am sure you could use something else.

[Trostle]

In the original post, I know that Phil was not talking about converting glow engines to spark to use in Old Time Stunt.  However, for the record, the PAMPA OTS rules do not allow such converted engines to be eligible for the spark ignition bonus.

Please do not ask me the rationale for this because I cannot explain it.

Keith

[Randy Ryan]

The idea is to use a gas/oil mix. How would an ABC engine do on that mix?

WHy necessarily gas & oil?

[De Hill]

In the original post, I know that Phil was not talking about converting glow engines to spark to use in Old Time Stunt.  However, for the record, the PAMPA OTS rules do not allow such converted engines to be eligible for the spark ignition bonus.

Please do not ask me the rationale for this because I cannot explain it.

Keith

Hi Keith,

Perhps I can explain the rule. If a MODERN Schneurle ported or Modern baffle ported glow engine is converted to Ignition, it will run like a Glow engine. The converted engines are much more powerful and dependable than an old Authentic spark ignition engine. If you allow the converted engines to compete, you will basically make the old engines obsolete.  Very few people fly Ignition engines because they are more trouble to run than glow engines.

[Andrew Tinsley]

Hi Phil,
          Just go ahead and do it! I have a converted Merco 60 which I have run on points only, electronic ignition with magnetic and optical pickups. Its just great fun, use any fuel you like, methanol, ethanol, regular gas, use castor or 70 weight oil, its up to you and you can have a whale of a time experimenting. 70 weight oil is used in lightplane applications, so try your local airfield, (for some reason they have different definitions of viscosity, ask for 140 weight, its the same as SAE 70. If fuels won't mix, use a little toluene or even ether.
  Have patience, I have ebayed several Madewell 49's, they have been reasonably good, except they seem to wear con rods. I have made 3 replacement rods to date. Have not had the trouble with its little brother the Vivell 35. Lots of people say get an O&R 60 or 23. They do start easily but they are very cheaply made. Most of mine had to be worked on to get them acceptable to me. In control line use they wear VERY quickly, you have been warned!
  I have used the Merco in developing my microprocessor controlled ignition system, that engine has been totally reliable and easy starting.
  The only thing that I really know very little re spark ignition is the suitability of ABC engines. Guess they need the usual synthetic oil same as you would use on an ABC glow. Don't forget that petrol runs much hotter than methanol. It may be the running clearance of the piston / cylinder will be on the slack side due to the higher temperature. Now there is another topic to explore and have fun!

Drop me a PM if I can help in any way.

Andrew Tinsley

[FLOYD CARTER]

Several points and issues have been raised and answered here.  First, converting a glo motor to run on spark ignition can be done either by making a set of mechanical contact points (timer), or by installing a Hall-effect pickup.  The Hall pickup MUST operate with a transistor circuit driver for the spark coil, because the Hall I.C. on-off current is rated at less than 20 milliamperes, while the spark coil current peaks at about 4 1/2 Amperes. The transistor unit is merely a switch with current gain.

PAMPA rules no longer permit "converted" engines for competition.  But for "fun flying", such conversions are just fine.

For competition, the most successful sparkers tend to be the larger ones.  Say, .49 cu.in. or larger.

A very good fuel for spark engines is Coleman Lantern fuel (naptha) and SIG castor oil, in a 3:1 mix (25% oil).  Pump gasoline is also OK, but some gasoline will not mix well with castor oil.

Some use ordinary glo fuel in spark engines.  Not too much nitro, but 10% is usually OK.  Glo fuel consumption tends to be about twice the rate of gasoline or Coleman fuel, but as long as you plan ahead with a larger fuel tank....

I always break in a new spark engine using SIG Champion glo fuel with all-castor oil base (using spark ignition, of course). .  The castor provides superior lube for a new motor, and the increased fuel flow tends to keep the engine cooler during the break-in period.

Transistorized ignition products, coils, spark plugs, etc. are available from Larry Davidson
Samchamp@jetbroadband.com.

You will discover that modern transistorized spark ignition and NiCad or Lithium batteries almost completely eliminate the former hard starting problems often associated with spark engines.  I typically can hand start my spark engines with 2 or 3 flips every time.

If anyone is interested, I have many spark engines for sale.  Among them, an Orwick .64, a Cunningham .64 (a modified Orwick) and a Super Cyclone .65.  E-mail me for details.

Floyd Carter
Aeroplyco@aol.com

[Garf]

WHy necessarily gas & oil?

Cheap/no nitro needed. I'm looking foreward to when I retire and have little money to spare.

[Jim Kraft]

Phil; If you have a source for methonal, you can buy Bakers AA castor from Sig for $23.00 per gallon. No hazmat on castor. On the other hand, gasoline is much cheaper as it takes about half the amount for the same flight time. Most of my sparkers seem to start a little easier on glow fuel, with or without nitro. Cold weather can be tough for either one. They can be frustrating at times, but to me, worth every bit of it. I fly one in either an old free flight plane with radio, or C/L, almost every time I go to the field. Nothing like the bark of an old sparker to make you smile.

[Andrew Borgogna]

Guys
When running pump gas in my O&R .61 I used Torquo (sic) 70 weight rear end oil.  It's green in color and worked quit well.  I got the info on this from my very good friend the late C.J. Jordan.  He was a long time SAM member and had a collection of spark engines that would make anybody jealous.

As long as we are on the subject, lord have I had a bunch of trouble getting my Super Cyke running right on spark.  I have tried three coils, two spark modules, three different plugs, and both NmH batteries and alkaline batteries.  Right now I have stepped back to a basic setup of coil, condenser, and batteries.  With the electron spark modules everything looks great EXCEPT no spark.  I have cleaned the points cleaned and gaped the plugs, I really don't know.  Anyway the basic setup is now getting a good spark on the bench later I am going to try and fire it up.  It really is weird, but then that's what makes spark so much fun.
Andy

[De Hill]

What brand of spark plug are you running Andy?

That could be your problem.

[Andrew Borgogna]

I have two NGK CM-6s and one that has no label on it.  To follow up on my last posting I took the plane out and started it with the basic spark setup.  It would not hand start, it did pop, but it started quickly with a blip of the starter.  Before I get flamed for using a starter on a Super Cyke the engine is a replica and the man who made it told me it was OK to use a starter on it.  The engine ran great right up to when I tried to advance the timing and my finger had a close encounter with the prop.  Anyway I shut down the engine to tend to a bleeding finger.  I was encouraged by the fact it did start and it ran quite well.
Andy

[Robert Zambelli]

Gents - I published this a while back but it may be of benefit here.
First off, I will state that spark engines, WHEN PROPERLY SET UP, are as reliable as glow.
I have proven this with over ten years of sport and contest flying with my OK Super 60 powered Viking with only ONE non-start (I inadvertently shorted out the batteries)

Here's my simple formula:

3 parts regular gasoline, 1 part castor oil. Many ask why I do not use motor oil. Simple: It's formulated and engineered to be pumped through an engine, not to be burned in a pre-mix. It has a variety of additives like viscosity stabilizers and detergents.  These contribute greatly to fouling your plug. While castor will indeed leave carbon deposits, they are easily burned off.
Regarding the lubrication characteristics of castor, the compression is as good as it was ten years ago and the front bearing and bushing have no play whatsoever.

I use a simple automotive condenser - it's from a mid-60s Ford

I use only AC plugs - I've had terrible results with Champion

3 AAA Ni-cads

Stock points, direct triggering (many people swear by the transistorized triggering systems - they seem to work well but I refuse to mess with something that has worked perfectly for so many years)

Z-mod (epoxy fill) for the coil


I have had the same setup for over ten years and NEVER experienced a problem.
I NEVER have to clean the plug. In fact, I haven't had it out for around four years.
I have NEVER had a problem with the points (They're original). I clean them with alcohol once a year.
Keep it as simple as possible.
Those who have seen the Viking fly can attest to how well this setup works.
And here's one last trick. When I feel the engine starting to lean out at the end of the flight, I fly it very high and it leans out a bit more, usually for three or four laps. I'm convinced that this burns off any excess deposits on the plug and keeps it clean.

For what it's worth.

Bob Z.

[Andrew Tinsley]

Hi Robert,
 I think that you are 99% correct! The only thing that I would query is the use, or non use, of transistorised modules. These are both simple and totally reliable, I note that you have had terrible experience with Champion plugs. Try those same troublesome Champion plugs with a transistorised module, you will find that they suddenly work perfectly! Also plug fouling will be a thing of the past, no need to fly high when the motor leans out. Other than that I am totally in agreement with all that you say. Sparkies are actually the most reliable starters of all my engines!
  As a general aside, electronics are now so reliable that you can do very sophisticated things with an old sparky. My latest modules contain a small but sophisticated microprocessor. I have had fun in thinking up ways to use these little marvels. I can advance and retard my engines by rotating a small remote potentiometer or using a channel from a radio receiver. All this without moving the advance retard lever. I can set up an accurate engine timer for competition use. With older points systems that bounce and limit revs, I use the micro to recognise when the points bounce and ignore the spurious bounce signal So tired old Brown junior points that need an elastic band on them to get the revs up, can rev quite happily at revs way beyond the limit imposed by points bounce. How about a built in rev counter and so it goes on. Just making the point that electronics and high voltages can coexist!
  Finally a word of warning about back axle gear oil. This stuff is formulated for extreme pressures and it is full of additives to enable it to do this onerous task. Those additives are likely to cause very rapid plug fouling and have the wrong lubricating properties for our sliding and rotating requirements of a model engine. I have never risked using this type of oil and I would strongly advise people to keep clear of the stuff! If the local airfield is too far away to get the 140 weight oil (SAE 70). Then go to your local Harley Davidson dealer and get SAE 60, which I am told is used in Harleys. Better still stick to Castor, its the best all round oil for our use.

Andrew Tinsley

[Garf]

I wonder if synthetic diff. oil would work. We have a 55 gallon drum where I work.