ForcesR

One of the Ray English mods is machining down the diameter of the main rod crank pin to allow for the installation of a beefier bronze bushing, that is the blue bushing seen in your photo.

nswords

That looks very dry.

757jonp

My Feedback: (48)

Just my opinion.... looks like one of the slave rod clips came loose which allowed the pin to drift back into contact with the balance weight and boom! (see the mark on the balance weight) Trash flying around took out the other rod. Has the clip and washer been removed from the remaining slave pin, because I don't see it anywhere.

RAMMJETT

It's not just a matter of not exceeding Max rev's or temp in the air ,You also have to be sensible about throttle management (the amount of time you should expect to stay at full power), most of the flights I see of the saito 84-90 is like the pilots have the throttle on a on/ off switch , I just cringe when watching, waiting for the bang , you can't honestly expect any four cycle to stay together while doing a whole flight at close to maximum output (engine under maximum load). These are not simple chain saw engines . Four cycles have far greater mechanical limitations and should be respected as such .. . .A few bursts of full throttle in climbs or a burst across the field won't hurt but full flights revving like hell and diving at the field through 1/2 the circuit to gain RPM ,may sound cool but it's killing your engine . I'm actually surprised more don't blow up . Hell the real plane would blow up at the war power setting after more then a few seconds ..Quite frankly I think many are expecting the impossible .

darod07

Hi all!
I received good news from Japan... My engine was shipped to the factory there for investigation of failure ( broken piston skirt ). I got reply they will repair my engine free of charge.... This is all a know at present stage. I wonder if they share what caused such damage and if this was the only damage or maybe result of other failure. Anyway big plus for Saito 👍

RAMMJETT

Cracking and braking is normally caused by detonation, this is common knowledge in the automotive trade , One of the basics they teach so we as techs can identify failures . This is when the mixture starts to burn normally but because of, excessive heat / excessive load / poor fuel / incorrect fuel mixture / or incorrect timing or a combination of any of the those .. The mixture explodes prematurely somewhere before the end of it's normal burn . This is the knocking sound you sometimes hear when you set the engine to lean or load it to heavily with to big a prop.. Detonation is extremely damaging to a engine, . instead of a normal burn when the flame front burns across the top of the piston and pushes the piston down smoothly and evenly . Detonation is like a hammer blow that hits the piston and causes cracking and breaking of parts , I believe you have a typical detonation failure , very common . Feel lucky they are going to warranty it, but be careful not to do the same thing to the new one .. Gas engines burn fuel ,Diesels detonate fuel and there parts are 10X stronger to deal with it , when gas engines detonate they break . This is not the fault of Saito ,To make a small four cycle have enough power to fly a plane it needs to be a extremely high performance motor and will detonate easily, the problem for us is compounded because we can not always hear what the engine is doing up in the air .. Telemetry will tell you temp and RPM but will not tell you that you are detonating, that's why I say you must be very careful with these engines 'keep the RPM moderate unless doing vertical climbs and keep WOT to a minimum . . cheers

su27flanker

Does anyone know if the FG-90 will have enough power for the Toprc F4u? its not a light bird maybe 16kg+

CK1

My Feedback: (60)

Try closer to 19 or 20kg ! I weighed mine yesterday at 42.5 pounds (19kg+) dry . And yes several of the TopRC Corsairs have been flown on the FG90R3 . Keep your engine as far forward as possible as well as all your batteries and you still need 3 to 4 pounds (at least) added ballast as far forward in the fuse as it'll go

nswords

I,m flying the TF FW190 with the FG60 and it has plenty of power. The two planes are about the same weight.

nswords

I,m flying the TF FW190 with the FG60 and it has plenty of power. The two planes are about the same weight.
error

su27flanker

thats good to hear so it wont be under powered then, what prop is everyone using? 24x12 or 25x12 suitable?

nswords

22x10 on the fg60

sagibr

Does anyone know if I can use a 3 blade 24x10 on the fg90?

Tom ling

I believe the recommended prop is a 24x10 two blade, so it would definitely be “over propped” but I’m sure it would turn it well, just not in its power band.

ForcesR

The recommended prop is a 24x12, not a 24x10 for the FG90R3. Using a 24x10 will cause the engine to over rev at full throttle especially when the aircraft is descending. As mentioned by Tom ling, using a 3 blade 24x10 the engine will be over propped causing lower RPM and the result will be the engine will not reach its power band. Also using a 3 blade 24x10 prop will possibly cause over hearting of the engine which is something you do not want to happen on an expensive engine. If you really want to use a 3 blade prop then the best choice for the FG90R3 is a 22x12 3 blade, or use the 24x12 2 blade which will ensure the engine will not over rev even during a descending dive. That's what I use on my FW-190 powered by the FG90R3 fitted with a

24x12 2 bladed prop.

jeremyilj03

My Feedback: (14)

All: I have been trying to break-in my new Saito FG 90 R3 and am having some issues with smoke/oil coming from the exhaust on #3 cylinder. I have two videos to show what I am talking about. I have done the basics in terms of troubleshooting: Checked valve lashing, swapped spark plugs between cylinders (issue did not move to another cylinder), made sure boots were firmly seated, checked for loose fasteners, etc. Thus far no 'smoking gun' has been identified. I have experience with gas engines and have never seen this much oil and smoke coming from one cylinder. Thus far I have run two tanks of fuel (32 oz per tank) and have not seen much of a change. I was thinking maybe this is a break-in issue. I have even tried to vary the needle valves and it has not resulted in any change to the periodic smoke and oil issues from #3 cylinder.

If anyone has any advice or recommendations I sure would appreciate it, otherwise I guess it will need to go back to Horizon.

CK1

My Feedback: (60)

The cylinder smoking is # 3 cylinder . Check your plug wire routing #1 is at the top , #2 is counter clockwise from #1
( bottom left from front view ) , #3 is clockwise from #1(bottom right from front view)

jeremyilj03

My Feedback: (14)

I typed the incorrect cylinder number. The issue is with #3 and I have verified the plug wires are going to the correct cylinders.

ForcesR

What RPM are you getting with a 24 x 12 prop after break in with the LS & HS needles leaned for maximum RPM?

jeremyilj03

My Feedback: (14)

I'll fire it up tomorrow and take a tach to it and let you know. I do know from the sound it doesn't sound like it is anywhere near 6500 or 7000.

CK1

My Feedback: (60)

Have you check for spark on the #3 plug wire .

jeremyilj03

My Feedback: (14)

Yes, I removed the plug and rotated the prop by hand and say that the plug 'sparked' as expected. Unfortunately, this doesn't tell me if its is sending a signal for every firing when the engine is operating. I wonder if there is a loose connection or an insufficient voltage going to that plug.

CK1

My Feedback: (60)

It sounds like you've done your due diligence. You've checked spark . You've checked plug wire routing . Checked valve lash ,which also means no dislocated push rods found . You've leaned it out to no resolve . Swapped plugs . It may be time to send it to Horizon for them to check it out . If you had the tools you might check compression on all cylinders to see if they're all comparative to each other.

ForcesR

The reason I asked what the maximum RPM was at full throttle is to confirm if the LS & HS needles were leaned enough for maximum ground RPM. The # 3 cylinder is blowing smoke & oil because the needles are still set too rich. Your # 3 cylinder is doing exactly what my did during break in, it stopped blowing white smoke and oil when I leaned both needles to achieve maximum ground RPM. The maximum RPM on the ground IMHO should be 6000 - 6200 RPM using a 24x12 prop, do not try to achieve a higher RPM. Just for your info, 6500 RPM on the ground is not a good idea due to the engine will be in the danger zone for over revving in flight, especially if you select full throttle during a decent and banking maneuver. The danger zone for over revving in flight for the FG90R3 from my experience begins at 7300 RPM due to the prop unloading in the air.

RAMMJETT

From the video it sounds like one cylinder is completely dead , check the temp on it when running to see if it's lighting up , I think it's so rich that you are fouling plugs , once fouled it wont come back by leaning unless you clean the plug .. but they tell you to run it like that for the first few tanks just to seat parts in . just get some fuel through it before making it leaner . they tell you to run it so rich it's almost dying . when your ready to start leaning it out remove the plugs and clean them , you can also try to rotate the plugs to different cylinders to see if you have a bad plug .. cheers ..