Jimmy Hoffa

My Feedback: (3)

I never hold full throttle for more than 5 to 10 seconds. I do a lot of 3D, but hover takes a little over half throttle.


Yes. I guess I keep it too rich. I'm always worried about running it too lean.

Thanks for a lot of good information.
Phillip

rlmcnii

My Feedback: (3)

JimmyH,

I am neither teacher nor preacher. But, if I were you, I would go back to the beginning and retune the fuel guzzler.

1. HS out 4 turns, LS about 1mm inferior to the face of the plastic throttle arm.

2. Start the engine and let it warm up. It will be very rich and probably require the glow-driver be left on.

3. WIDE-OPEN throttle and lean HS to peak rpm. As you know; adjust the HS ONLY at full-throttle.

4. Now, start on the LS. It will probably be very rich also. Turn in 1/8 of a turn at a time, let stabilize, and check the transition. You will have to go farther in than you think. Keep turning and checking. When you reach the point that it either dies or hesitates as you open the throttle you just need to back the LS off about 1/8 of a turn and you should be there. Some posters recommend the "pinch-test". I have never used it, but it must work!

5. Back to WIDE-OPEN and re-trim the HS to be 300(or so) rpms rich of peak. Re-check the throttle transition and touch up the LS if needed.

Once well-tuned it will require very little re-adjustment. Large changes in ambient barometric pressure or temperature may necessitate a little triming of the LS to maintain a nice transition.

This last thought may bring disagreement: The only power setting at which you must worry about sufficient richness is wide-open. If the LS is set too lean...the engine will not transition from idle and will die; if it isn't running, a lean mixture won't hurt it. If the HS is set too lean (that is...far too lean. Note the 300 rpms rich-of-peak!)...it wont run at full-throttle. It will pop and bang and may throw the prop. Same situation; if it isn't running, a lean mixture won't hurt it.

One last thought, compliments of more experienced posters: A little castor oil is apparently a very good thing for Saitos.

When well-tuned, I bet you will easily get 15 minutes on a ten-ounce tank. Good luck

gjeffers

thats right, i get a 9 min flight on my 100 on a 10oz tank and still have 1/4 tank left at end.

XJet

Today, while I was dripping a little oil down the pushrod tubes of my SA100 (part of my regular maintenance schedule -- i do this after every 10 liters of fuel) -- I figured "hey, if there's a path from the crankcase to the cam-box, I should be able to suck on the crankcase vent and draw the oil down the pushrod tubes -- instead of waiting for it to slowly trickle down -- right?"

Well guess what?

There appears to be absolutely *no* path from the crankcase to the pushrod tubes.

I sucked as hard as I could -- and there was no movement of the oil in the tubes.

Figuring that perhaps I'm a little old and feeble in the lung department, I rotated the engine to BDC, blocked the crankcase vent and then turned it 180 degrees -- thus creating quite a strong vacuum in the crankcase.

I would have expected this to draw the oil down the pushrod tubes, into the cam-box and then along the crankshaft towards the rear bearing.

Nope, not the slightest movement.

It would appear that either the rear bearing is a sealed unit (thus effectively blocking the flow of air or oil out of the crankcase) or the crankshaft is such a good fit in the front part of the crankcase that it effectively seals the path.

With this in mind -- I'm wondering (especially in light of the "squealing SA125" thread), whether *any* oil can make it to the camshaft area in normal engine operation?

Has dripping oil down the pushrod tubes saved *mY* engine from a horible fate?

I'm reluctant to pop the top off the cam-box and have a look (because it's running *so* sweetly right now) but as the days draw shorter, I'll do just that. In the meantime, I'd like to know if other folks observe the same lack of path from crankcase to pushrod tubes on their Saitos -- particularly those which have the vent nipple in the backplate rather than in front of the rear bearing.

jb86

My Feedback: (8)

i don't think i would put my mouth to that. use a glue syringe, and draw it.

jon b

NM2K

My Feedback: (14)

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If you tune the engine for peak rpm after it has first started running, the mixture will lean out as you burn off the fuel during the flight. If this is the situation, the engine will slow down during the flight and may eventually quit from over heating.

If you have compensated for fuel burn-off by richening the mixture that extra bit that we are all familiar with, and your engine still slows down during the flight, you may have a problem with getting sufficient cooling air to the engine.

Frankly, the 18x6W sounds a bit steep for a Saito 1.80 unless you are very careful with the initial setting and the amount of cooling air available to the engine.

I have a case of the fuel of which you speak, but haven't used it as yet. If the problem began since you started running this fuel, you might want to borrow a tank of fuel that previously ran well in your engine and try that.

As an aside, you MUST readjust the needle valves when switching prop sizes/brands, glow plug types and fuel brands/nitro percentages.

What is a Type H glow plug? Never heard of it. Sounds like a heli plug?


Ed Cregger

Hobbsy

My Feedback: (102)

ED, I have several brands of fourstroke plugs, Hangar 9 (4) stroke SuperPlugs in particular have a single H on them. Probably for hot.

RVM

On a 12oz. tank, flying IMAC and 3d, I get about 15 minutes with 25% nitro and an APC 15x4w (about 9200-9500 RPM) on my .82. I think I will be able to lean it a bit more as I fly it. The engine only has about 2.5 gallons through it. Midrange still showing quite a bit of smoke when going from idle to full. I think 16+ minutes is feasible on a 12oz tank with this setup. I'm going to try an APC 14x4w and ProZinger 14x5 and see how that goes.

Birman

Horizon Hobby is out of stacks for the 91, but I found them at Wholesale trains http://www.wholesaletrains.com/Searc...it2=++Search++

for $4.69. Now, which Bru line filter is used for the 91 stack or are the filters all the same?

Larry

PS: Found out that they want $8.95 S&H...

Jimmy Hoffa

My Feedback: (3)

Besides a leak down compression test, is there an easy way to check if the valves are sealing? How about removing the cylinder and taking the piston out, then pouring a liquid into the cylinder (with glow plug installed) to see if any fluid leaks past the valves?
Phillip

c550

My Feedback: (16)

I have 2 .30's one .82 and one 1.50, can I join?

Regards,

Dave

mstcitabria

Here is a comparitive pic of the TurboHeader with a stock Saito 1.00 muffler, it's excellent quality, machined from high quality T6 aluminum. Thanks Jim, great item for our Saito's!!
mstcitabria

eclecticant

My Feedback: (10)

HI I have found the differance between the 150 & 180. Guess what 1mm in hight.


KEN

Hobbsy

My Feedback: (102)

I just re-visited the TurboHeader and my Saito .82
Fuel WildCat 15/18%80/20 lube
Plug GloDevil 4c Special OSf equiv.
Prop==APC 14x6

RPM stock muffler 9.570
RPM TurboHeader 9,750
The optional baffle does not effect the rpm a measurable amount but makes the .82 sound like the 1.00. Without the baffle the .82 is louder than the 1.00. I must apologise to Jim, I used an appropriately sized socket to tap the baffle into back of the back half, it bottomed out one tap sooner than I expected, hence the circular marks, my bad. It goes into the muffler with the cone toward the engine. I added a 3 inch piece of Aerotrend extension to the TurboHeader, no rpm change.

I'll bring mstcitibria's audio link of the 1.00 up here for those who have not heard it. http://www.yourfilehost.com/media.ph...e=WS_10005.WMA

gjeffers

xjet, ive had my 100 apart many times and it always has oil galore in the cam area and also the rocker area.
also the rear bearing is not sealed (unless someone put one in) oil flows through very easy

Hobbsy

My Feedback: (102)

X, some guys love to cause other people to worry, me I don't worry, there is no way so many Saitos could last so long if they weren't doing it right. I just ran my 1.25 today for long full throttle runs testing the TurboHeader to see if long periods of full throttle would get it hot enough to change its sound. It didn't happen and the 1.25 makes no audible mechanical sounds. Gobs of oil on the test stand though.

az3d

My Feedback: (59)

Ed, I think you are right about the prop. I talked to a guy at BJ's model engine service where I plan on sending my motor. He thought the load on the 18x6W prop may to much causing the motor to overheat. I actually use it on a 150 not a 180. If it did not leak as much burnt fuel I would probably change props and not send it in for repair. Any recommendations for a 3D prop for this motor. BJ's recommend a 18x6 as opposed to a 18x6W. My plane weighs aprox 9.5 lbs. I wonder if there is such a thing as a 17x6W? Will an 18x6 prop be a good 3D prop?

av8rdavid

Sorry to be off topic.....
I'm re-building my Fa-65 that completely lost compression to the point where it turns over and barely feels like its causing any compression.....I can blow into the exhaust and air goes right out of the intake port without closing completely....
Can this mean i need a new set of valves and springs or are the cylinder valve seats shot to point i need a new cylinder head or both?
I replaced the piston ring and no difference was noticed.....
Any suggestions would be very helpfull...
Thanks.

Dave

av8rdavid

Sorry to be off topic.....
I'm re-building my Fa-65 that completely lost compression to the point where it turns over and barely feels like its causing any compression.....I can blow into the exhaust and air goes right out of the intake port without closing completely....
Can this mean i need a new set of valves and springs or are the cylinder valve seats shot to point i need a new cylinder head or both?
I replaced the piston ring and no difference was noticed.....
Any suggestions would be very helpfull...
Thanks.

Dave

N1EDM

My Feedback: (2)

I'm assuming that the valves are set properly. Are you certain that the timing is right? Could the cam be 180 degrees off???

Just my $.02

Bob

Hueb

Hello,
New member here.
Thanks everyone for sharing your issues, solutions, and knowledge. I have found this thread very interesting.
I currently have (2) FA 100's, (1) FA 82, and (1) FA 72
Looking forward to learning more about them.

Ernie Misner

Where's William Robinson lately? Hopefully Hueb will become a member soon.

I've been off working with the digital photography for some time....

Thanks,

Ernie

TimC

Ernie, sad to say, Bill's house burned down and he lost almost everything he owned. There is another thread started by Hobbsy concerning this.

av8rdavid

Cam has never been touched.....However, what is the correct setting for the cam?

w8ye

My Feedback: (16)

Sounds as though your exhaust valve is stuck open or the pushrod has gotten caught under the edge of the adjusting cup?

Make sure the throttle is open when you hand turn the engine for compression?
With the piston at the top the mark on the cam goes straight down.

There's a hole in the intake cam that aligns with the lifter hole when the timing mark is straight down. Use the small end of a pushrod in the lifter hole to keep the cam mark down when you install the cam. When assembling the engine, the small end of the pushrod goes towards the rocker arm.