Kmot

My Feedback: (24)

TC: got a drill press? You could make velocity stacks yourself on one. Why wait 5 months?

Thunderchild

Good point Kmot.



TC

Bipe Flyer

I have a couple of questions about velocity stacks. A velocity stack is used to smooth our airflow, right? Should it be used when you use an air filter? Is there an advantage to using it without an air filter?

Thunderchild

Bipe Flyer

Use the search function below in this thread for some very useful posts by Bill Robison "The Guru of Saito" on the subject.

Cheers,

TC

mstcitabria

TC,
Fired up my new Saito 100 for break in this past weekend, what a little jewel! Got really scared when I discovered that my air filter on the velocity stack disappeared after the motor kicked and ran backwards for a few seconds and melted the foam element out of the filter! Three tanks later I discovered that the air filter foam was missing and thought maybe the intake had injested the foam element! Be careful and check your air filter if your motor has ran backwards, my motor ran for less than two seconds backwards and the foam element was completely burnt away, would hate to get that crap caught in the valves...........................mstcitabria

jasonlacey

Thank you you all for the Welcome.The roughness on the top of the piston is more like it has been scuffed hard with a very coase grit sandpaper, and it is only in the centre of the piston top the area of the glow plug.The engine has only had about half a gallon of 15% S&W high performance fuel through it,using a OS type F glow plug.Fuel and plug good? Excellent thread.

FFOURU

Well, I got talked out of the Hanger 9 Arrow trainer, and into a Hanger 9 80" Cub arf. Using my Saito 72 on it, and had to turn the carb around. After removing the intake pipe and putting it back in, I am not sure that it feels as tight as it did before. I appears that there is quite a bit of pipe sticking past the o-ring. I really don't think I want to "wire it to the cylinder like some suggested. Do I need to worry about the "looser" feel? It doesn't seem to leak air.

And, are some servo's better as throttle servo's than others?

FFOURU

Mounting the 72 in the h-9 Cub. The angled exhaust pipe doesn't want to set up quite right for the muffler. Can anyone tell me if one of the 6" flex pipes with a pressure tap will fit the 72. If so, which one..... I guess what I am asking is what size pipe fits the 72?

Thunderchild

Good Tip mstcitabria, thanks for the heads up. We operate in a very sandy environment here in West Oz so I will persevere with air filters to protect my investments!!

blw

My Feedback: (3)

I *think* it is this one. If not, W8YE will give the right link:

http://www.horizonhobby.com/Products...dID=SAI300T74B

w8ye

My Feedback: (16)

The flexible pipe adapter that BLW gave is for the big block Saito which are 14mm dia. The 72 is 12mm dia.

http://saito-engines.info/mufflers.html

Flex pipe with pressure tap 12mm for 72
http://www.horizonhobby.com/Products...D=SAI182TD1112

Another flex pipe with tap 12mm for 72
http://www.horizonhobby.com/Products...D=SAI325R578B3

90 degree adapter 12mm for 72
http://www.horizonhobby.com/Products...rodID=SAI65140

Original exhaust manifold 12mm for 72
http://www.horizonhobby.com/Products...rodID=SAI8075A

Original style muffler 12mm for 72
http://www.horizonhobby.com/Products...rodID=SAI8074A

Solid pipe with pressure tap 12mm for 72
http://www.horizonhobby.com/Products...rodID=SAI8074A

Current all threaded manifold for cast muffler 12mm for 72
http://www.horizonhobby.com/Products...rodID=SAI8075B

Current cast muffler for 72 12mm for 72
http://www.horizonhobby.com/Products...rodID=SAI6574C

There's one other flex pipe and you would use your existing muffler on the end or some combination thereof, 12mm for 72
http://www.horizonhobby.com/Products...rodID=SAI65111

FFOURU

Thanks Guys,
The Saito Info is woofully lacking in dteal about what pipes fit what motors, and I was frustrated. Now that I know it is 12mm, I can select the right one.[8D]

Any ideas on how much flight time I should expect out of an 11 oz tank in the Cub with the 72?

Hobbsy

My Feedback: (102)

The easiest way to find that out is to set your fight timer for 10 minutes, land when it sounds off and take a peak. Somebody will post here that they get 5 minutes, somebody else 25 minutes and you still won't know.

William Robison

My Feedback: (3)

Here we go again.

As Dave said, three people, three answers. But generally speaking a Saito will burn one ounce of fuel per minute per cubic inch at full throttle when adjusted properly and matched to the plane and propellor, with 15% nitro fuel.

Chart is most popular sizes with running times for 10 ounces of 15% fuel. First column is full throttle start to finish, second column is with a 60% throttle average. Times are rounded to the nearest minute.

Engine full 60%
FA-56 17 29
FA-65 15 25
FA-72 14 23
FA-80 13 20
FA-82 12 20
FA-91 11 18
FA-100 10 16
FA-120 8 14
FA-125 8 13
FA-150 7 11
FA-180 6 9

The most common reason for excessive fuel consumption on a Saito is the LS needle too rich – at ½ throttle you are still running on the LS adjustment.

Fuel economy is also greatly improved with the use of an intake stack and a Bru-Line fine mesh air filter.

Bill.

rclement

My Feedback: (1)

I've decided to get a Saito 125 to power my Mayhem. Will I need to get a Perry pump for it?

w8ye

My Feedback: (16)

SAITO MUFFLER compatibility

The Saito mufflers have a different thread pitch than the OS and Magnum four stroke engines. A OS 52 pipe will not fit a Saito 56 because of the thread pitch issue.

Ray44

My Feedback: (4)

Greetings Everyone, Man what a tremendous amt of info here and I've been thru all the pages, just super.
I've got a problem maybe.

I just rec'd my second Saito, a 150 and bought it used, think it was first purchased in '93.
Took it out of the box and first thing I did was turn it over What A Shock!! I could spin it over with my fingers.

Not even a hint of compression. Don't know what possessed me but I went ahead and drilled/reamed a new
prop for it. Put the prop on and tightened the nuts and gave it a spin, now all kinds of compression.
So most likely a stuck valve. This situation happened one more time and now all seems fine.

I did get the engine started on a test stand, kinda hard starting but it seemed to run gud and have plenty of power and real
nice idle.

I hate to install this in my new plane and then have to take it back out.
Is this going to be a recurring problem??
Your Opinions Greatly Appreciated

Thanks,
Ray

w8ye

My Feedback: (16)

Engines that have sat around for a while typically have this problem. If it still has good compression after running it a little, it should be OK.

It is most likely the exhaust valve. If you pull the valve cover and put some penetrating oil on the valve stem and work the valve up and down some, it may help. If you open the valve by hand and not by turning the prop, the push rod will jump out of its socket on the rocker arm and cause a problem.

blw

My Feedback: (3)

Thanks Jim. I was tired and should have looked up the size for the flex pipe.....

William Robison

My Feedback: (3)

Catch up.

Page 120.

SaCCaL72

If the engine vibration while still on the plane didn’t change, then it’s improbable that you bent anything. You can pull the glow plug, sight the crank on a fixed point, then turn it slowly. Any amount of bend should be visible this way.

Jettpilot:

These engines mostly backfire only when they are being run too lean. Best prevention/cure is open the needles a bit. If you get the backfire mostly on starting then you aren’t giving the engine enough prime.

Page 121.

bfreee:

I don’t think you’re going to get good vertical running with the tank 4-5 inches behind the engine. If there is a way to move the tank closer that would probably be the way to go.

rlmcnii:

Quote:

I am no WR.

And aren’t you glad? If there were two of us the earth would crack open and we’d both be lost! Haw.

Your advice there about the backfiring is dead on.

Page 121.

Kaastrup:

The 14x10 on the FA-100 is too much pitch for sport flying, your air speed will be really high when the engine comes on. You should prop for 9500-10000 on the ground for best results. My opinion, anyway.

beausol and bfreee:

Tank height reference is always from the center line of the tank.

Page 123.

Doug:

Stuck valves are something we seldom heard of until recently, and they seem mostly on the FA-82, and usually very low time on the engine. No explanation, but a guess would say the bore of the vgalve guide might be slightly small, and it needs to run a little to get it free. As I said, just a guess.

Page 124 (current)

BipeFlyer:

When you mount an air filter you need something to mount it to, and except for the smallest Saitos there’s nothing there. You either have to cobble up some sort of nubbin to stick it on, or get an intake stack. Easier usually to get the stack. Yes, there is a definite advantage to the stack, it generally traps most of the fuel that’s normally spit back out of the carb, and increases your fuel economy. With an air filter on it even greater savings can be had.

Ffour:

The FA-72 has a nasty habit of developing an air leak at the upper end of the intake tube. If you’re sure it’s not leaking have at it. But if the engine starts acting strangely replace the o-ring and washer, then tie it down with the safety wire.

Someone aked about the length to make his own stack. Don’t remember who or where, but generally the length is from 2 to 2½ times the inside diameter. Longer does a better job of containing the fuel. And you need a flare on the end to secure the air filter body.

Rcclem:

If the tank is positioned correctly you should have no need of a pump for your FA-125.

Ray44:

It’s also possible you had the throttle shut. None of the Saito engines show much compression unless the carb is open.

I think that’s all. If I’ve missed any questions please ask again. And I’ll try not to get so far behind again.

Bill.

William Robison

My Feedback: (3)

And new members:

286 SaCCaL72
287 mcmike
288 Ghostrider FIN
289 jasonlacey
290 Pergus
291 =Mudbug=
292 Ray44

Welcome to you all.

Bill.

XJet

My SA100 took a bit of a dirt-nap today and bent the pushrods and tubes.

I"m thinking I'll straighten the bent tubes and the pushrods until the replacements arrive (I'm in NZ) but thought I'd just check to see if there was any reason why I shouldn't do this.

I haven't checked yet but I don't think the crank is bent -- it went in vertically and the only visible part of the motor was the intake manifold -- the rest being below ground level.

It still turns freely and there appears to be no other damage apart from the rods & tubes.

I'm thinking I just have to lift the cylinder to remove both? (yes, I'll keep track of which rod/tube is which and which way up they go. :-)

William Robison

My Feedback: (3)

XJ:

You can pull the push rods without lifting the cylinder, but it does have to come up to get the tubes.

Your engine uses solid steel push rods, they can be straightened - there's no need to replace them. The tubes also can be straightened, use a rod that's a close match to the inside diameter and just push them back out. Support them on a wooden block and press the rod through. A light touch with a hammer on the outside of the tube often helps, using the rod as a mandrel to buck the hammer.

Bill.

William Robison

My Feedback: (3)

XJ:

Additional - the push rods and the tubes are both "Handed," there's a top and bottom.

The bottom of the tubes is plain, the top has a ridge to keep it from going up through the rubber.

The push rod has one end normally rounded, the other is tapered to a smaller rounding. The tapered end is the top.

Bill.

rclement

My Feedback: (1)

Thanks Bill! [8D]