Hobbsy

My Feedback: (102)

Pictures duly noted, if those were in a Saito it would be a very long engine.

Kmot

My Feedback: (24)

Okay, so now you know I am a natural born smart azz!

nauticom

Hello all.
I am a confirmed Saito user; including the following: 1-100, 1-90TS, 1-170R radial. That 170R is the best engine I have every owned; its in a 76 inch WS Corsair, pulling a 16X8 3 blade. Next Saito coming is the 450R for my Ziroli Corsair.
Please add me to the Club.
Thanks,
Bob Masterson
Western PA
nauticom

William Robison

My Feedback: (3)

Bob:

#115 nauticom

Welcome.

Bill.

solafein

#70 here

I seem to be having a little difficulty with my Saito .91. After my second gallon of fuel I set the valve lash and adjusted the high speed needle to 500 RPM below peak. I noticed a slight lack of power on Monday, I have 5 gallons through it, and checked the adjustment. The wide open throttle was pretty much dead on at around 9750 RPM. I leaned it out to check where it would peak at and RPM fell off. I then richened it and it continued to drop. I peaked it at around 9500 RPM and then re-set it to 9100. All this tweaking did not foul up power too much as it will continue to climb until it just hangs there and I get bored after a second or two, I don't have the patience for hovering. I am wondering if I am over engineering this or if I need to do something about it besides "shut up and fly". More data: I set it when it was 100+ degrees outside and about 35% humidity. Recent tweaking has been at 70 degrees and high humidity as we are into the preliminary cold season here in Sunny Rural Southern California.

Kmot

My Feedback: (24)

Hi,

High humidity means there is more water vapor than normal so there is less oxygen. Less oxygen makes less power.

Cheers!

-Tom

solafein

I guess our little single cylinder dynamos are a little diffrent than my car where cool, moist and dense air adds 20 horses and five hundred RPM to my redline.

Thunderchild

Yeah, but I think what is being referred to is humidity. This affects density altitude (hence "hot and High" trials for big aircraft certification) which will bring a noticeable drop in performance.

Your staement is right though at the opposite end of the spectrum - COLD and DENSE air s good. HOT air is bad. HOTand WET air is even worse as it is LOW DENSITY.

Cheers,

TC

Kmot

My Feedback: (24)

Cold and wet is bad too. Major difference between cold, dense "dry" air and humid air.

Thunderchild

Indeed. Large aero engines (non fuel-injected) suffer from intake icing under these !QUOT!cold and wet!QUOT! conditions which is more the risk for performance loss. I do not see any reason why their little brothers in our models would not have the same problem. Fortunately in my country, the climate is not generally conducive to these icing conditions (only a couple of locations on the east coast that MAY have exposure), but you North American and European types may have seen this phenomenon. I would be interested to hear any tales of carby icing [8D]

N1EDM

My Feedback: (2)

Geeze guys,

Haven't you ever heard of Water Injection????????

Bob

Thunderchild

Water injection is an entirely different concept. What we are talking about here is induction icing. Simply put, when pressure drops (induction) so does temperature. This is what happens in the induction pipe attaching the carby to the engine. You may have even noticed water droplets accumulating on the outside of this pipe while the engine is running. This is because of the temperature drop of the charge mixture travelling from the carby to the combustion chamber inside the pipe ans is a good inication of high ambient water content.

When conditons are just right, the pressure drop allows moisture suspended in the air to come out of solution and form droplets. These droplets can then turn to freezing sludge and adhere to the inside of the carby - generally around the butterfly in large engine carbys, but any protruberance will offer a nice "grab hold" for ice to accumualte. If bad enough, the ice will eventually choke off the inlet and deprive the engine of fuel/air. We have carby heat selection in big aircraft where an alternate air source is provided by typically drawing it from a heater muff around the exhaust pipe. This preheats the air and prevents icing. The penalty if used in non-icing conditions is of course a power loss because you are now inducting hot air into the engine.

In big aeroplanes it is generally accepted that you are at risk when there is visible moisture in the air (rain or rain clouds) with the OAT at around plus 5 degrees celcius.

old-pilot

gjeffers; How do you fasten the extension (brass?) on the saito muffler?

Bill; it would be easier to mention the Saitos I don't have . It would be a shorter list.

gjeffers

old pilot, i used a piece of 1/2 in o.d. brass tubing (13mm i.d.) and it was a snug fit to begin with but i used permatex high temp red and it has been on for hundreds of flights and never come off

Kmot

My Feedback: (24)

Yes.

As I understand it, from my training as an aircraft mechanic, alcohol/water injection was invented during WWII as a means to replace the extra fuel enrichment used in large radial engines in bombers to keep the engines from detonation during WOT at takeoff with full fuel/bombs. Using fuel to cool the cylinder temps was a waste of precious fuel and shortened the range of the bombers. Water injection replaced the fuel with water and alcohol. Increasing the range of the bombers because they still had that extra bit of fuel. As a bonus, it was discovered the water and alcohol injection increased performance by around 10% @ WOT because of the cooler temps at WOT only and also reduced carbon buildup. The technology was then transferred to all Allied fighter aircraft. On the throttle quadrants, there was a setting at the very top of the travel, labeled "WEP". Across this area, copper safety wire was twisted. If the pilot was in dire straights, needing more power, then he would push the throttle into the WEP breaking the copper safety wire and engaging the alcohol/water injection system. WEP stood for War Emergency Power and the reason for the safety wire was so the mechanics would know the engine had been pushed to extremes and might need to be R&R'd.

However, "water injection" is not the same thing as high water vapor (humidity) and displacing air with water will not make more power.

-Tom

William Robison

My Feedback: (3)

And no atmospheric condition, or water injection, will raise the red line of an engine - that's a mechanical limitation.

Bill.

w8ye

My Feedback: (16)

We are getting OFF-TOPIC here. The topic is CLUB SAITO.

Lets cool it on the air density and water injection topics.....

We are only talking here about how many SAITO's you own and how you love them.

Any problems with your Saito... Start a new thread.

Jim Moderator

William Robison

My Feedback: (3)

Jim:

You are both right and wrong.

The atmospherics are off topic, but this thread is far more than "I love my Saito."

Review earlier postings, please. Maintenance and service are also being discussed here.

Bill.

w8ye

My Feedback: (16)

Bill,

I realize your point. But the thread is much too long for any solutions to be of any value in the long term. No one will ever be able to find the problem or the solution in the future.

Starting a new thread will make it easier for someone to match their problem in the future.

Enjoy,

Jim

William Robison

My Feedback: (3)

Since you put it that way, Jim, I have to agree.

Bill.

Thunderchild

Giggle Giggle....................... Speaking of which I haven't seen any comment on my using a 56 Saito in th CMPro Lancair. The aircraft will weigh around 2.5 to 2.8 kilos (5.5 lbs to 5.6 lbs) if that helps any of you who are presently operating this little gem.

I suspect I'll be okay, but I would appreciate any hard fact or experience if available.

Cheers,

TC - back on topic Jim!!

solafein

Anything?

XJet

Actually although a reduction in pressure *will* cause a reduction in temperature, the main reason we get icing is because of the latent heat absorbed by the fuel as it evaporates after being atomized in the carby.

Just pour any volatile liquid (such as methanol or gasoline) onto your hand and you'll immediately notice that as it evaporates, it makes your hand feel cold. This latent heat effect is many times stronger than the effect of the small pressure drop in the intake manifold.

The more volitile the fuel, the more likely you are to get carby icing.

This is why direct-injection engines (where the fuel is injected into the combustion chamber) don't have any real manifold icing problems.

w8ye

My Feedback: (16)

Alright you guys, this is the end of all the direct injection talk in this thread. Anymore will get ZAPPED.

Feel free to start yourself a new thread if you want to talk about it.

Enjoy,

Jim

Kmot

My Feedback: (24)

Back on topic about Saito engines:

This photograph is of my Saito 1.20 running on a test stand. The rough looking texture on the carb intake pipe is not rough cast aluminum. It is water condensing on the outside of the pipe. This is the moisture condensation on a high humidity day that was being discussed regarding the performance of a Saito engine.