No More "Ragged Runs"

[Gerald Schamp]

Well the Master, Bob Reeves fixed my "Ragged Runs" problem, along with changing to the Power Master YS 20/20 fuel, I sent him some on my manifolds for him to make the changes to that he discribes elsewhere. Got them back. Took the old manifold off the engine (Saito .40) that I had been having all the fuss over. Installed one of Bob's manifolds, set it up like he said, and WOW, what a difference. The engine came to life, very little adjustment, nice tuneable RPM range. Turning a Thinder Tiger 11.3 x 6.5 prop, 8100 to 8500. Will turn it at 9000, but no need too. I then took another of the manifolds and installed it on a second used engine I had gotten recently, set it up the same as before and exactly the same results. They run identicle, very impresssive to say the least.

I haven't had a chance to go fly the plane yet as I've kind of been fighting a cold, yes a cold in August, but as soon as I get better I'll try this puppy out. I know it will be fine, just by the way the engine runs on the test stand.

So, Mr. Reeves is "The Man" for sure when it comes to making these four strokes run right. Its especially good too, for someone like me that is not an engine person, that can make a fix for the engine run problems, send it to me, I install it, set it like he says, and presto, it works. Just like it is supposed too. 

[proparc]

This is what makes Bob contribution so significant. You don't have to be an engine man to rock with the Saitos.

[Bob Reeves]

Just wait till you fly it 

[Steve Helmick]

Joe Yau was having problems with his Saito .56 on 15% Cool Power, so I got him a jug of Wildcat YS 20/20. Has anybody run both brands? Wildcat is considered to be a good brand of fuel around here.  Steve

[Bob Reeves]

Joe Yau was having problems with his Saito .56 on 15% Cool Power, so I got him a jug of Wildcat YS 20/20. Has anybody run both brands? Wildcat is considered to be a good brand of fuel around here.  Steve

I bought 4 gallons of Riches Brew 20-20 from a guy at Brodaks for a really good price and other than the jugs leaking haven't seen any difference between it and PowerMaster 20-20. However I have not actually ran it without it being mixed with some portion of PM 20-20. I've been topping off the can on my flight box every other time with each so always have some mix of both.

Use PowerMaster 20-20 for the base line (we know it works) then run a couple tanks of the Wildcat. This will tell you if it's OK or not..

[proparc]

It is important to differentiate what YOU require, as opposed to what the ENGINE requires. If YOU require a certain nitro require, that’s fine. But don’t confuse that with what the ENGINE requires.  I have actually seen, and read about Saito’s running FAI fuel. That’s, right-0% nitro. Saw that at Sepulveda RC field in Los Angeles. In addition, I have also read about Saito’s running FAI fuel a number of times.

At the opposite end of the spectrum, I have read numerous times, about RC guys running Saito’s like a “poor mans” YS. They drop the oil content, and really jack up the nitro. 30% nitro in a Saito is not uncommon in RC. Saito’s will haul the mail if you do that but; the first thing to go in them is the bearings; next you will take out the head.

A lot of confusion about 4 strokes stems from their relationships in RC.  The YS and the Saito were every specifically designed, to serve the needs of different sectors of the RC community. YS are, and have always have been, targeted toward the dedicated RC competitor. Even their early-pumped 2 stroke motors were targeted there.

The extraordinary success of Saito motors is due to their highly focused direction at the RC sport flyer. Most RC flyers are not competitors; they are “Sunday flyers”. The Saito is the RC communities LA46.  They are without question, the least fussy, and most user friendly 4 stroke ever developed. 

It is a testament to how flexible and user friendly they are in that, they will run absolutely fine on a fuel designed SPECIFICALLY for the needs of a competition motor i.e., YS.  They will also run fine, on a range of fuels that the YS simply will not.

The ONE thing the Saito’s don’t seem to tolerate is different glow plugs. They really only seem to run well on one plug, and that is the F plug. This is virtually universal throughout the RC community. In my case, I simply could not get a steady idle on my 72 without the F plug, (yes, I set idle). The other issue is, my big block had an annoying “surge” in flight without that plug. 

This has caused Saito no end of embarrassment, and consequently, they contracted with a major plug manufacturer to duplicate and make the F plug. When you purchase a new Saito, the plug that it comes with, is basically an F plug “knock-off”.  But rumors die hard in the RC community, and guys will still automatically chuck the OEM plug, and pop in an F plug. The OEM plug, very closely duplicates the run characteristics of an F plug, but very simply, will not last as long.

By the way, I have used an F plug in an ST46 and ST51, and it ran beautifully.

[Bob Reeves]

I always chuck the stock plug after break in. Heard you should do that with any engine as the plug could get contaminated from metal bits during break in. May or may not be true but for the cost of plugs what the heck...

I'm suspecting you are getting away with 10% because 1. you are running a 72 in the same size airplane I'm running a 56 in and 2. You don't fly in Oklahoma's 100+ temps with 15 - 20 mph winds. 

[proparc]

Going forward, one of the first things I am going to experiment with when I purchase my next Saito’s will be, 0% nitro fuel.  My next 72’s will be tested for; specifically quick hand starts and steady running, in particular above 45 degrees, on no nitro fuel. Nitro is expensive, and if I can eliminate that from my 4 strokes than so much the better. If not, back to 10%.  

My 62’s will not be tested on 0% nitro. Not going to bother LOL.  The other thing I will try, is a constant run as opposed to my 4/8 break. Most of the cats in Open fly constant speed, and that is actually the 72’s normal run characteristic. Probably will up the diameter and drop pitch. Will definitely look for constant speed on the 62’s.

[Joe Yau]

Didn't see this post till now..  I've been using the Powermaster YS20/20 for atleast 2yrs with couple of Saito.56, and just last fall I thought I try some Cool Power 10%, and then 15% cause I was low on YS 20/20.  I was actually surprised it ran o.k.. with no real issues.  This was around October, so it was much cooler.  It ran fine through the winter seasons till the temperature came up in around May/June of this year.  A few signs of problem showed up. As it seems lack of power to penetrate the wind,  and it consistently sags through the sqr-8. I had to fly it soft to make it through.. which was very annoying.  I've tried it with a richer setting, and it would get slightly better, but then the run would varies from a 5.6/lap ( beginning of flight) to a 4.85 near the end.  Then I tried the PowerMaster YS 20/20 just to see if it makes any difference.  The first thing I notice was it has more torque at the same rpm.  and was more rock solid through out the whole pattern with no noticeble sagging.  Unfortunately no one sells PowerMaster Fuel up here in Canada.   Big thanks to Steve Helmick, he got me the next best alternative fuel the Wildcat YS 20/20, and brought it up to our stunt contest.  I haven't tried it yet.. but I will this weekend, and will report back on the results.  

[proparc]

Something that we are not touching on here concerning nitro is, engine setup. Quite possibly I could be doing something in my setup i.e. valves, carb etc. that eliminates the need for extra nitro. I like to think it’s the special mojo in my guitar playing hands that allows me to setup my Saito’s with extra TLC such that, it doesn’t need extra nitro. Alright, alright, that was a total bunch of crap, but you get the idea.  

Also remember, I don’t use commercial fuel. When I put in 10% nitro, I know I am getting EXACTLY 10% nitro.

[Joe Yau]

Something that we are not touching on here concerning nitro is, engine setup. Quite possibly I could be doing something in my setup i.e. valves, carb etc. that eliminates the need for extra nitro. I like to think it’s the special mojo in my guitar playing hands that allows me to setup my Saito’s with extra TLC such that, it doesn’t need extra nitro. Alright, alright, that was a total bunch of crap, but you get the idea. 

Also remember, I don’t use commercial fuel. When I put in 10% nitro, I know I am getting EXACTLY 10% nitro.

Hi Milton,

I've tried different valve adjustment from a tight .002" to a loose .003" and have tried a few different carbs, from a Tom Dixon / 1/4" choke screw, PJ carb w choke screw, R/C carb with BR choke screw mod, stock C/L carb with spray bar drilled to PA size. I also played with different mufflers to get the proper back preasure needed for the desired rpm.  I think because the .56 is near borderline pulling a 68 oz stunter, it really needs the nitro at the warmer temp.  I guess I could try a .62 and run 15% maybe. 

[proparc]

Hi Milton,

 I think because the .56 is near borderline pulling a 68 oz stunter, it really needs the nitro at the warmer temp.  I guess I could try a .62 and run 15% maybe.  

The 56 never had true 60 power. I would rate it on par with a Stalker 51-well setup. Now remember, the U.S. Nats, the Worlds and the European Championships were all won on the 56, so it's no tomato. But that said, the word in the RC community is that the Saito 62 may be the best Saito of all time.

The 72 is only for if, you want to try to get a date with Kim Kardashian.

[proparc]

Hi Milton,

I think because the .56 is near borderline pulling a 68 oz stunter, it really needs the nitro at the warmer temp.  

If I was running a 56, at 68oz,15% nitro for sure. Lets talk about valves,(not enough discussion there).

Tighter valves tend to increase rpm and decrease torque. This is critical, tighter valves don't do us justice in stunt because, the valves have less time in contact with the head, and consequently cannot transfer their heat as effectively. This makes for hotter and more inconsistant runs.

Looser valves stay in contact with the head longer and consequently, transfer heat better which makes for cooler running and more consistant runs, which is what we want in stunt. In addition, I have come to the conclusion that how you set the valves makes a big difference.

You must toss the little blue valve gauge that came with your Saito and get a professional automotive feeler gauge. Preferably Kaster brand-the best. I know that may pi#$ you off but, I very strongly feel the expense is worth it.

Just to get you straight,.002 is tight,.003 is medium, .004 is loose.

When you can get 1 to 2 flips hand start consistantly, you got gold.

[Joe Yau]

Tighter valves tend to increase rpm and decrease torque. This is critical, tighter valves don't do us justice in stunt because, the valves have less time in contact with the head, and consequently cannot transfer their heat as effectively. This makes for hotter and more inconsistant runs.

Looser valves stay in contact with the head longer and consequently, transfer heat better which makes for cooler running and more consistant runs, which is what we want in stunt. I have come to the conclusion that how you set the valves makes a big difference.

You must toss the little blue valve gauge that came with your Saito and get a professional automotive feeler gauge. Preferably Kaster brand-the best. I know that may pi#$ you off but, I very strongly feel the expense is worth it.

Just to get you straight,.002 is tight,.003 is medium, .004 is loose.

When you can get 1 to 2 flips hand start consistantly, you got gold.

Well, now you mentioned it..  I used to set it to .002" tight, meaning the feeler guage is fairly tight in the gap, but not enough to open the valve.  Usually I expect less sagging, instead it would charge out of corners, and seems to have almost too much power on the climb of verticles paths etc.  but slows down on the middle of sqr-8 & OH-8 where it needs torque.   basically more power at the wrong place..   Anyhow, It is till just recently thinking why does the valve needs to open more? or is more better or less is.   I'm at .003 mid/ loose setting on both valves.   Do you set the intake & exhaust differently?  something I haven't tried yet.   

I used to bump off the compression for starting.. usually one bump will starts when primed properly with inverted mounted set ups. But the problem is the odd times it would run backward, which sends hot exhaust out the intake and would melt the 1/4" nylon choke screw..  it's why I use the starter now. 

[proparc]

Remember .003 is not loose, it's medium-.004 is loose. I tried differential valve settings-gained nothing. Of course I can't dictate to you what valve setting you should use,(that is personal preference).

4 strokes run with a much higher BHP which is why they get such better fuel economy. They run much much hotter.

I never chase maximum power, alway-always the most consistent run. To that end, I drop nitro, and try to setup, to allow the motor to run below its max. Dave Fitzgerald does this with his 75 Merlin, and I do it with my 72 Saito.

[Joe Yau]

Remember .003 is not loose, it's medium-.004 is loose. I tried differential valve settings-gained nothing. Of course I can't dictate to you what valve setting you should use,(that is personal preference).

4 strokes run with a much higher BHP which is why they get such better fuel economy. They run much much hotter.

I never chase maximum power, alway-always the most consistent run. To that end, I drop nitro, and try to setup, to allow the motor to run below its max. Dave Fitzgerald does this with his 75 Merlin, and I do it with my 72 Saito.

What I meant by .003 mid/loose is when the .003" feeler gauge could slide through the gap somewhat easy. so it could almost be a tight .004 etc.  not sure if the .56 could be set up like the .72. As it doesn't have a lot of reserved power like the .72.  But it is performing well with the 20% nitro though.   

[proparc]

Yes the "big block" allows you to run with plenty reserve. Its cut through bad air like no engine I have ever flown.

Once, I pulled the stooge on it, and it got hung up in a plant. The plane stopped dead, and all I saw was a bunch of green mulch fly through the air, the next thing I know, it took off like a rocket. After the flight, I went back to examine the plant, and there was nothing left but a stub. My APC was covered in green.

[Joe Yau]

Joe, you didn't state what prop you were running.

I'm currently running a Beechwood Xoar 13x6 2-blade on the .56. and launch rpm is 8100-8300.

[Joe Yau]

Tighter valves tend to increase rpm and decrease torque. This is critical, tighter valves don't do us justice in stunt because, the valves have less time in contact with the head, and consequently cannot transfer their heat as effectively. This makes for hotter and more inconsistant runs.

Hi Milton,

Just out of curiosity..  what do you set the gap at on the .72?

[proparc]

Hi Milton,

Just out of curiosity..  what do you set the gap at on the .72?

Thought you would never ask. My 72 will not start at all at .002. It runs ragged at .004. It only runs on one setting. .003 I know, I know-why. I have no idea. I have set it at everything from .001-.005. I have tried differential settings. It only runs at .003.

Heres the kicker, my Saito 40A only wants to run at .002-go figure.

When I get my Saito 62-you guessed it will probably only want to run at .004 LOL.

In any event, I set them where each motor is happy and content.

[Bob Reeves]

Guess it's time to offer up my opinions on valves and fuel just to give another perspective.

Maybe I've been lucky but haven't noticed the valve settings on the engines I run (30 to 62) all that critical. I use the little feeler that comes with the engine and just make sure they are not set too tight. If anything mine end up a thousandth or two over. Have acquired a pretty good feel for how much play needs to be in the rocker arm after the valve is set and can usually tell right away if it's too loose or too tight just by feeling the rocker arm movement.

One of my theories on how to make a 4 stroke work is to make the fuel system as free flowing as possible. I believe a 4 stroke needs all the help it can get being able to suck in as much fuel as it can, remember it only sucks for 1/2 as many revolutions as a 2 stroke so lets cram in as much fuel as possible. This is the reason for using a conventionally vented clunk tank (remember uniflow has to force air through liquid in order to vent), muffler pressure and YS 20-20.

I don't say this often enough, one big reason to run PowerMaster 20-20 besides the bigger bang you get with 20% nitro is the oil in YS 20-20 is low viscosity making it easier to move through plumbing.

Sorry, but I also completely disagree with the above statement "The 56 never had true 60 power". My first forray into a larger 4 stroke was a 68 ounce Score with a 56 which I flew for two years basically cleaning house at local contests flying Advanced against Piped 60's and 61's in the same size airframes. I was running a 13-7 Rev-Up at around 8 grand. My present stunt ship also has a 56 and it leaves nothing on the table flying against piped 65's, don't tell my 56's they don't have the power of a 60 they sure don't know it yet.

[proparc]

Just so you guys know. In the RC 4 stroke forums, those guys go on for thousands of threads debating the Saito's. While Bob and I don't agree on the muscle of the 56, the one thing that can't be debated is Saito quality.  By the way, I have ships designed specifically for the Saito 56. Interesting enough, I think the 40A has amazing muscle.  My ST 46’s can’t hang with it.

I have never had any issues with Saito’s concerning fuel draw; I actually don’t notice any difference in draw between my 2 or 4 strokes. The statement that Bob made about 4 strokes fuel draw is EXACTLY the statements the RC boys make on their forum. Makes sense, but I simply never noticed any difference.  What I did notice, is that MY Saito’s won’t tolerate dirty fuel. I have had to actually strain my fuel at the field to finish my flying day.  

That said, all is not well with Saito in the RC community. A lot of RC boys are pissed that Saito makes you pay extra for their velocity stack. The velocity stacked doesn't do what it looks like. We tend to associate velocity stacks on vintage Ferrari's. Consequently, the second we see them we think-vroom!!

Velocity stacks on Saitos, simply catches extra fuel that would spill out the carb. That happens on Saitos because, of the distance from the spraybar to the top opening of the carb. It increases fuel economy. It doesn’t cost much but the RC boys see it as an irritant.
If you look at the new O.S. Max Alpha 4 strokes-because they were designed to squarely take aim at the dominant Saito’s-they come with velocity stacks and loudly proclaim it.

The other issue which, doesn’t bother me at all, is the Saito design of exhausting its lubricating oil out the side of its crankcase. The RC boys were complaining about having to clean the insides’ of their cowls because of Saito’s design. OS Max’s also, very loudly advertise their new oil recirculating design, (brilliant really) where the oil never leaves the crankcase.  

[proparc]

I have come to the conclusion that, in light of the recent series of posts by Bob and I, that maybe Bob and myself should have posted some of these things sooner. The significant differences in how Bob and I setup our 4 strokes, points to the aforementioned flexibility and adaptability of the Saito.

Partly what killed the 4 strokes in stunt, was the perception of the need to have extremely specific and custom equipment necessary to get them to perform properly in our event. Stunt flyers are EXTREMELY independent when it comes to setting up their front end. Very seldom will you see two setups exactly alike.  The perception with 4 strokes was that, this independence would be taken away from them.

I have flown my entire 4-stroke experience with the stock RC carb that came with my motor- it performs beautifully. Bob has flown, very successful, with a carb he designed and developed-it performs beautifully. The Saito’s are not rigid motors that must be setup a certain way. Saitos have flown successfully with miniature Roots type blowers that you see on top of dragster motors.

 I think that the Bradley Walker article did more to harm the use of 4 strokes in stunt than any other thing. The level of complexity and specificity outlined in that article was to me, mind-boggling. If I had to run ANY motor like that, I would quit the hobby.  The setup on my 72 is SIGNIFICANTLY simpler than the setup on my ST46.

My Saito’s have NEVER seen an electric starter, (I don’t own one). And they have NEVER needed it.  Some people can’t get them going without one. My Saito’s will actually run quite fine without an OS Max F plug. They just won’t run very long LOL.

While I applaud Horizon Hobby’s attempt to meet the needs of the Control line stunt flyer, with their Control Line dedicated Saito’s, I thought that the actual implementation itself, was half-baked, (I still do).  Just about everyone knows that one of the key elements in getting your Saito to perform properly, is the careful and specific break-in procedures outlined in their manual. The carb on the CL Saito’s, preclude you from following those guidelines.

All in all, if EVERY Control Line Saito, just very simply came with a Bob Reeves carb, just about all of the issues with 4 strokes would be over.

[proparc]

Like Bob, I came to the conclusion that, what we needed was a way to control the amount of air coming into the carb, in addition to the amount of fuel.  Bob’s carb solves both problems. 

Bob’s “variable venturi” design, gives us, the control line flyer, the same level of control over the motor that, the RC boys enjoy with the RC carb, (high and low speed setting etc.) 

This is the carb that we need, to make the Saitos viable out-of-the box Control Line stunt motors. I honestly don’t see anything more that is required.

[Claudio Chacon]

Like Bob, I came to the conclusion that, what we needed was a way to control the amount of air coming into the carb, in addition to the amount of fuel.  Bob’s carb solves both problems. 

Bob’s “variable venturi” design, gives us, the control line flyer, the same level of control over the motor that, the RC boys enjoy with the RC carb, (high and low speed setting etc.) 

This is the carb that we need, to make the Saitos viable out-of-the box Control Line stunt motors. I honestly don’t see anything more that is required.

Absolutely. Bob's mod to the the RC carb is as simple as it is brilliant. It just WORKS EVERY TIME. Rock steady runs, flight after flight after flight... Period. I bought the CL version of the Saito 72 and modified the CL carb furnished with the engine as per Bob's directions using the same barrel that comes in the CL carb, so, as an extra bonus, I didn't even had to make a new barrel. I can't me more satisfied with my 72. LOTS of usable POWER.
If you are on a low budget and want a SERIOUS stunt engine to compete at ANY level, consider Saitos with Bob's modified carb. You WONT regret it!

[Joe Yau]

Thought you would never ask. My 72 will not start at all at .002. It runs ragged at .004. It only runs on one setting. .003 I know, I know-why. I have no idea. I have set it at everything from .001-.005. I have tried differential settings. It only runs at .003.

Interesting.. so it's that critical.      The .56 always starts, and seems to runs fine from  .002 - .003.

[proparc]

Interesting.. so it's that critical.      The .56 always starts, and seems to runs fine from  .002 - .003.

Now remember, MY 72 is that critical. If you say your 56 runs from .002-.003, I believe you because, thats sounds more normal.

Attached are pictures of the Saito 72. The first picture is the 72 that will replace my current one,(yes I going to get another one LOL). The second one is the CL. If you pay close attention to the pictures, you will see that they are different motors.

The CL is based on the A model and the RC is the B model. While they are both 72's, the idea that I would have to set them up differently is quite feasible.

[Joe Yau]

I notice the newer version of the .72 r/c has a new crankcase that is suppose to be 15% lighter.  Is that the one you're referring to?

[proparc]

I notice the newer version of the .72 r/c has a new crankcase that is suppose to be 15% lighter.  Is that the one you're referring to?

Yes, and the lower crankcase on the B is narrower but, I also suspect the compression ratios may be different. They definitely used to be.

[Joe Yau]

Yes, and the lower crankcase on the B is narrower but, I also suspect the compression ratios may be different. They definitely used to be.

Are the CL ones higher or  lower in compression?

[proparc]

Are the CL ones higher or  lower in compression?

I was hoping you would tell me.

They used to be different. The last high compression "FAI" engine made by Saito was-surprise the FA72.

I will find out, thats for sure. Call me "CSI" proparc.

[Joe Yau]

the next best alternative fuel the Wildcat YS 20/20, and brought it up to our stunt contest.  I haven't tried it yet.. but I will this weekend, and will report back on the results.  

Well,  I finally got a chance to test it out the fuels today.  I started off with one flight with Powermaster YS 20/20 for base line, launched at 7700 rpm gives me around a 5:2/ lap on 68' lines c2c,  and then I tried Byron YS 20/20, the rpm seems to picked up about a 100 (7800) or so, so I turn the choke screw in a bit to 7700rpm.  It seems to have about the same power, maybe a touch more on the vertical.  and then I tried the WidCat 20/20,  right off the start the rpm went up again.. about another 150 rpm. So I turn in the choke screw more.  but it bottomed out at 7800 rpm, and my lap time was 5.0-5.1 a little faster then I like.  It definitely made more power, almost too aggressive on the exits of the maneuvers, then it ran out of fuel just after the Hourglas maneuver.   So, it burns up the fuel faster then the Powermaster & Byron fuel.. and made the most power, seems to me that's the sign of higher nitro content.  I think if they made a YS 15/20 it'll be about perfect.  In conclusion:   The Byron fuel is the closest to the Powermaster for performance wise, and the Wildcat fuel made the most power overall.  (feels like it has 25% nitro!) and all of the three fuel ran strong through out the pattern with no sagging issues.  

[Bob Reeves]

Less oil can produce the same results as adding nitro cept the engine won't be happy. Poor two ounces of each brand in tuna cans and let them sit for a couple weeks to evaporate the alcohol and nitro. Then compair how much oil is left.

One of our club members somehow ended up with a gallon of fuel that the manufacture (not Fox or PM, might have been Wildcat, can't remember) forgot to put any oil in.  Two flights on an OS 40 four stroke and the engine was toast but for a short time it ran like it was on steroids.

[Joe Yau]

Less oil can produce the same results as adding nitro cept the engine won't be happy. Poor two ounces of each brand in tuna cans and let them sit for a couple weeks to evaporate the alcohol and nitro. Then compair how much oil is left.

One of our club members somehow ended up with a gallon of fuel that the manufacture (not Fox or PM, might have been Wildcat, can't remember) forgot to put any oil in.  Two flights on an OS 40 four stroke and the engine was toast but for a short time it ran like it was on steroids.

Hi Bob,

The Powermaster fuel I've been using are the original YS20/20 and not from VP, wonder if the new stuff is any different?  I will do the oil content comparison test on the WildCat fuel next.