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smallest conversion?

Old 04-14-2003, 01:22 AM
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flyinrog
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Default smallest conversion?

been awhile since I looked at all the mags but I remember seeing conversions for down to ..40 size engines to ignition and gas/oil mix is that as far as it got? is that still available? does it go down to .10?........Rog
How much is that kind of thing now a days?
Old 04-14-2003, 02:00 AM
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wvarn1957
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Default smallest conversion?

I am currently running a Magnum 52 and an OS FP 60 on ignition and gas. Probably could go smaller, depending on the configuration.
Old 04-14-2003, 08:35 AM
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flyinrog
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Default smallest conversion?

who made the ignition components, that was what I meant in my thread... thanks wvarn.. how reliable is your set up and how much $ did it run........Rog
Old 04-14-2003, 01:01 PM
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wvarn1957
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Default smallest conversion?

I am using CH Ignition systems with syncro spark. The FP 60 runs better than it ever did on glow. Neither engine developes quite as much power as they did on glow. They are about 500 rpm off the top end, but are much more reliable. The idle is dramatically improved on both engines.

The only modifications needed other than the mount for the pulse switch is a new needle for the carb. Since the air/fuel ratio for gas is about double that for methanol, the needle needs to be slightly larger in diameter and have a longer taper. Otherwise, rich to lean adjustments may be as little as half a turn. What I found worked best is a needle that has a tip cross sectional area about 30% of the orifice in the carb body. The taper length is about 1.5 times longer than for glow. This gives about two turns from too rich to too lean.

Other than the cost of the CH system ( approximately $130 ) all of the other pieces I fabricated.
Old 04-14-2003, 03:46 PM
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Default smallest conversion?

wvarn1957,

I'm not familiar with either of those engines performace figures. Could you provide the range (ballpark) before and after? Thanks.
Old 04-14-2003, 11:38 PM
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Default smallest conversion?

The Magnum 52 would normally run 10,000 to 10,500 depending on the prop. I ran it with a 12.25 X 3.75 on a fun fly and it would turn about 10,200. The OS 60 FP is a bushing engine and fairly long stroke, but it would turn about 10,100 with a 12 X 6 prop.
Old 04-15-2003, 01:45 AM
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Default smallest conversion?

wvarn1957,

Thanks. It looks as if the performance loss is not too dramatic, and the benefits of the conversion outweigh the limited drop off in RPM. I am following a similar RCUniverse thread on converting a Saito 1.80, and hopefully your success will be mirrored over there. What mixtures are you using??
Old 04-15-2003, 03:04 AM
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Default smallest conversion?

I use 15% Klotz in regular gasoline. Because of the higher temperatures running gasoline, the Magnum (4-stroke) does not seem to get as much top end lubrication as Glow. To compensate for this, I give the top end a shot of Klotz after every flying session. So far no problems. Each engine has probably 2 hours on gasoline.
Old 04-16-2003, 05:46 PM
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Default Whats the smallest...with walbro carb?

What's the smallest conversion (Or stock) gas motor with Walbro carb?

CrazyHerb
Old 04-17-2003, 02:35 AM
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Default smallest conversion?

From the research I have done, which is by no means exhaustive, it would appear that the OS 1.08 is about the smallest that you could mount a Walbro WA series carb on. Even the 1.08 would require about a 3/8" spacer behind the prop for carb clerance. Physical dimensions and configuration on any thing much smaller than that would probably preclude mounting a Walbro.
Old 04-19-2003, 07:23 PM
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Default Walbro for coverted glow 4-strokes

wvarn1957 (aka Shell Answer Man ),

Have you tried, or do you know of anyone who has tried, a Walbro on a converted (from glow) 4-stroke, and what the results were (as well as any difficulties)? Thanks.
Old 04-19-2003, 07:40 PM
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Default 4C micro gasser

Been there done that, results were untold amounts of agravation.
You have to make a new intake manifold for the Walbro carb. You have to do an oiling system for the lower end.
When you get done a 1.20 will burn about 12oz of gas per hour at 6000RPM and the oiling system uses about 2 oz per hour.
If you fly cross country then maybe, for sport flying stick with stock engines
Old 04-19-2003, 07:48 PM
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Default smallest conversion?

tkg,

The manifold issue does not present too much of a problem. I am not sure what you mean by "oiling system." Most of the discussions I have seen cover mixtures, not mechanics. What engine(s) did you convert? Thanks.
Old 04-20-2003, 01:08 AM
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Default 4c gasser

Engines were Enyas a 90 and a couple of 120s.
An oiling system is all about keeping these engines alive. Think about it, they are lubed by blow-by and use a glow fuel with 17-20%oil. When you go to gas you automatical use 1/2 the fuel and oil, even at 20% gas/oil you have about half the oil in the bottom end. If you go to 50-1 fuel you must lube the bottom end or else boom.
There is a normal style Walbro carb for 4c engines. It pumps from the intake pulse not the crank case. WT456 6.5mm venturi
Old 04-20-2003, 01:29 AM
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Default Would it be possible

TKG,
Would it be possible to run a slightly higher oil content with a super-grade synthetic oil like AMSoil....and still get some longevity from the motor?

CrazyHerb
Old 04-20-2003, 01:42 AM
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Default smallest conversion?

tkg,

I appreciate the additional information. I understand the principals involved, and the points you raise are good ones. What was the "oiling system" you used? Also, did you upgrade the bearings (assuming this is possible for the Enyas you converted). Thanks.
Old 04-20-2003, 07:33 PM
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Default Lube

Enya 90, raise up the vent in the crank case, squirt in some oil and splash lubbed.
Enya 120r GP, used the geared fuel pump to pump oil between the front bearings and a one way check valve out of the gear/cam box to the oil tank. Vent the oil tank.
Enya 120r used the system that the folks at Insitu used when they flew across the Atlantic. Oil tank and 2 one way valves one in and one out. The crankcase+- pulses move the oil.
Last engine had a custom two piece split ring to reduce oil use.
Old 04-21-2003, 01:28 PM
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Default engines

TKG: Is there a website for Insitu? Very interrsting stuff. Thanks Captinjohn
Old 04-21-2003, 07:26 PM
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Default smallest conversion?

Insitu Group Trans Atlantic flight
Old 04-23-2003, 01:08 AM
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Default Lube

Thanks tkg, I really appreciate your having taken the time to post the details of your modifications.
Old 10-21-2014, 10:19 PM
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Didn't Clarence Lee use a four stroke OS 60, one of the old original ones running on Coleman Camp Fuel and ignition to cross the Atlantic, or do I have my memories crossed up??

Also guys, the Zama carbs are a bit smaller in outer dimensions than the Walbros. That's why Keith was using them on the original BME Super Tiger .90 on gasoline conversions. I made a Walbro fit on my Super Tiger .90 gas conversion, but it took some massaging/finessing....

AV8TOR
Old 10-31-2014, 06:27 AM
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The first crossing of the Atlantic ocean was by Maynard Hill in 2003. http://www.progressiveengineer.com/p...aynardHill.htm
Old 10-31-2014, 06:56 AM
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Thanks Captain John. My memory of the event and details was correct.

AV8TOR
Old 10-31-2014, 05:45 PM
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Originally Posted by captinjohn View Post
The first crossing of the Atlantic ocean was by Maynard Hill in 2003. http://www.progressiveengineer.com/p...aynardHill.htm
Right fuel...wrong person!
Old 10-31-2014, 06:56 PM
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Whoops! You're right! Hey, at least I got the ocean right.

AV8TOR

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