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Saito FG-60R3

Old 04-08-2016, 04:15 PM
  #576  
sparky4lawndart
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Just adding on to the band wagon here...

I've just had the 5th cylinder failure (3rd on this motor) while in flight at a Scale Master event... Mid-throttle position, at least 4 minutes into the routine, 21lbs TF GS FW190, level flight...

I have two of these FG60's (originally bought from HH for a TF GS Zero and my TF GS FW190...

it's been either cylinder 2 or 3.. .no loose bolts... I check every bolt before every days flying... I run 17:1 Amzoil with 87 gas...

Folks at my flightline are convinced it's a hydro-lock issue but that's not verified... HH support told me that they don't sell enough of these motors that would force them to rectify in other way than to fix it under warranty.

As a result I feel terribly frustrated and disappointed that I invested so much into motors that will likely fail in the wrong part of the sky and potentially wreck one of my birds. I have several friends I fly with that have 84's that don't have this issue.. .

In the last two years the only issue I've heard about on 84's is that they heat to a lean setting and blow a rod or seize.
Old 04-08-2016, 11:23 PM
  #577  
the pope
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Had a friend who worked for a big model shop who had a issue with a particular servo . They would say thats the 1st they heard of a issue and would replace the servo and chuck the defect one in a box , full of other buggered ones . Just cause they say it dont make it true . Cheers
Old 04-09-2016, 07:36 AM
  #578  
BobH
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I'd like some one explain to me how a running engine can have hydra lock. If there was that much pooling of fuel in the lower cylinders surely the change in operation would be noticed.
Old 04-09-2016, 07:48 AM
  #579  
aquaskiman
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Originally Posted by BobH
I'd like some one explain to me how a running engine can have hydra lock. If there was that much pooling of fuel in the lower cylinders surely the change in operation would be noticed.
There is no way that can happen with the carb set up they have.
Old 04-09-2016, 08:10 AM
  #580  
radfordc
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I think the concern is that during a cold start, if a cylinder has excess fuel/oil, when the piston comes up on compression it might over stress the cylinder casting and create a tiny stress fracture. Later when the engine is running this stress fracture could eventually fail. Full size radials are subject to the same thing.

http://www.avweb.com/news/pilotlounge/182680-1.html
"If you detect a hydraulic lock on a radial engine the only certain way to cure it is to remove the lower cylinder spark plugs and let the oil drain out. Pulling the prop through forward WILL result in a bent connecting rod and/or expensive damage to the engine if it does not cause a catastrophic failure. Pulling the propeller through backwards only reduces the chance of a bent connecting rod; it does not eliminate the risk"

https://en.wikipedia.org/wiki/Hydrolock
Hydrolock is common on radial and inverted engines (cylinders pointing downwards) when the engine sits for a long period. Engine oil seeps down under gravity into the cylinder through various means (through the rings, valve guides, etc.) and can fill a cylinder with enough oil to hydrolock it. The seepage effect can be observed by the blue-white smoke commonly seen when a radial engine starts up. In order to prevent engine damage, it is universal practice for the ground crew or pilot to check for hydrolock during pre-flight inspection of the aircraft, typically by hand-cranking the propeller for several turns to make sure the crankshaft cycles normally through all cylinders.
Old 04-09-2016, 08:53 AM
  #581  
aquaskiman
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Originally Posted by radfordc
I think the concern is that during a cold start, if a cylinder has excess fuel/oil, when the piston comes up on compression it might over stress the cylinder casting and create a tiny stress fracture. Later when the engine is running this stress fracture could eventually fail. Full size radials are subject to the same thing.

http://www.avweb.com/news/pilotlounge/182680-1.html
"If you detect a hydraulic lock on a radial engine the only certain way to cure it is to remove the lower cylinder spark plugs and let the oil drain out. Pulling the prop through forward WILL result in a bent connecting rod and/or expensive damage to the engine if it does not cause a catastrophic failure. Pulling the propeller through backwards only reduces the chance of a bent connecting rod; it does not eliminate the risk"

https://en.wikipedia.org/wiki/Hydrolock
Hydrolock is common on radial and inverted engines (cylinders pointing downwards) when the engine sits for a long period. Engine oil seeps down under gravity into the cylinder through various means (through the rings, valve guides, etc.) and can fill a cylinder with enough oil to hydrolock it. The seepage effect can be observed by the blue-white smoke commonly seen when a radial engine starts up. In order to prevent engine damage, it is universal practice for the ground crew or pilot to check for hydrolock during pre-flight inspection of the aircraft, typically by hand-cranking the propeller for several turns to make sure the crankshaft cycles normally through all cylinders.
We are dealing with a engine that does not have a oil reservoir and gets its oil from the fuel, also a fuel system that only pumps fuel when the engine is turning over.

Last edited by aquaskiman; 04-09-2016 at 08:56 AM.
Old 04-09-2016, 09:03 AM
  #582  
BobH
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For hydra lock to be an issue for this engine one would need to turn it over using an electric starter when experiencing a flooded cylinder. Now if you pull the engine though before hand, making sure your engine is working properly you won't/ can't have hydra lock.
So clearly it is fuel related because there are no reports of #1 cylinder failing.
Repeated pre-detonation over time stressing the marginal cylinder strength? Just looking at possible issues here. Not trying to say that's the real cause.
I will use higher octane fuel just to be sure. Can't hurt.
Old 04-09-2016, 10:06 PM
  #583  
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This is rather disturbing given that we have all invested in what we believe to be a 'premier' product. I must say, this has made me wonder whether I will ever be able to fly this engine with complete confidence. Anyway, I suppose that at some point my disappointment will be minimized when it does carp itself....I would have seen it coming.
I am glad that there are enough people here to provide input on their thoughts and experiences, maybe we will be able to find a way to minimize the chance of failure, even if we cannot avoid it all together.

I thought I would chime in with some of my findings, maybe all the pieces of the puzzle will lead us to an answer that will save our investment.

I agree that the hydrolock potential is there, especially if it is in the lower cylinders all the time, but as people have said, the chances of the cylinder filling with oil, is not really a consideration. Fuel, yes, but not likely to be oil. We all know that the induction system of these engines has been a factory/design problem, and whether it is possible to redesign or create a fix, is available with many people with the skills, such as Ray English. I have not really followed up on his recommendations (if any) from him regarding this engine. I know the 84 has received a lot of upgrades to minimize failure. THis engine was supposed to have received the upgraded inlet and bushing scenario, but since I bought mine from rcjapan, I don't know whether I got these or not. Are all the failures happening on the new and the old version, or is it just one of the two?


Ok, so here are some things i have noticed on the engine, since I got it. I followed the break in procedure where I was running the engine as per the manual, with 15:1 redline oil mix. During the break in procedure, I was tilting the stand in order to get the lower cylinders rotated up, and it was clear that they only fired in the 'rich' state, when they were in the upper position. You can see clearly through the smoke coming from the pipes, and the cyl temps. After a litre of gas through it, I mounted it inverted on the stand, and did another litre that way. In order to heat cycle it, I was removing plugs alternately (probably not good for the ignition, but I would rather replace that than cylinders and internals). After the 2 litres of fuel, I mounted it in the plane, and leaned it up to good idle, transition and HS. It runs beautifully. Added the Keleo exhaust for 'that' noise. Love it.
I checked the cylinder bolts after the first two flights, and got a SLIGHT 'click' from them, just cinched them down. I did it again yesterday, and again, just a click. I am afraid to over tighten now, so will leave them for a few flights.
So, now on to engine temps......I installed a Spektrum TM1000 and put the probe on cyl 1, one fin down, directly under the exhaust port. I know it might not be the ideal place as it will be affected by EGT, but since I started there, and I have multiple flight data, it is my control and I will leave it there for now.
The engine is mounted in an El Cheapo Yak-55M as I wanted a stable platform to test it. Running in an engine on a heavy warbird is not ideal.
As you know, the Yak-55M cowl is like a big bucket, and I installed some louvres to help remove air coming into it. Before I went down this route, I flew it without the cowl for max cooling effect. I recorded temps as follows, all in Deg C.
Idling on tarmac - 110 to117
Mid Stick on tarmac - 115 to 138 (continuous for around 30 secs)
Full bore on tarmac - 125 to 147 (continuous for around 30 secs)
Its interesting to note that as soon as you back off the throttle, it takes around 8 secs before the temps drop down sharply to the idle range.

For flight, with a 22x8 Xoar wooden prop, the following
Mid to 3/4 throttle cruising: 120 - 130
Full bore continuous around the circuit 125 to 143
Full bore vertical - 145 to 155.

Its under propped for sure, there is not enough pitch speed on this prop, so will do a 22x10 on the next flight. There are a few things to consider here.
This plane will not prop hang without over-heating....any lack of airflow over the cylinders will see sharp temp rises.
The temps fluctuate a LOT and temp changes are RAPID. For example, after the vertical, up to a hang, I put her in a steep dive, and by the time I had pulled out of the dive, the temps were back at 130 Deg C. The changes are steep and quick!!

I then mounted the cowl and although there was no baffle, there were three small louvres installed behind each cyl, and I 'assumed' enough air going out, I have come to the conclusion, that assumption was wrong.

So temps were:

Idling on tarmac - 117 to 135
Mid Stick on tarmac - 125 to 140 (continuous for around 30 secs)
Full bore on tarmac - 138 to 155 (continuous for around 30 secs)

Again, temp drops were very quick

In flight we got:
Mid to 3/4 throttle cruising: 135 to 145
Full bore continuous around the circuit 145 to 150
Full bore vertical - 155 to 160 (it crossed the 160 mark briefly, and I immediately put her in a dive to cool down.)

From this I can see that regardless of where I have the temp sensor, this engine seems to have VERY rapid heat cycles from cooler to hot. I also took the time to get her to fly around for a circuit every now and again, completely inverted, to make sure those lower cyl's are seeing some action. I don't want to do too much inverted as the Keleo ring will probably fill up with oil.
I was thinking of finishing the 3 liters of fuel that I have, and then changing the ratio to 18:1 from 15. The plugs are burning a little oily, and although I am running it on what I think is a little rich, I would rather reduce the oil content and keep it rich a little, than lean the hell out of it.

I am not sure if any of this is any use but given that parts are breaking, there may be some connection between that and the big temp fluctuations that I am finding. Metal behaves very differently at different temps and these parts are seeing big variations in temps. Well, mine does anyway.

Regards to all,
Andy
Old 04-09-2016, 11:39 PM
  #584  
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Originally Posted by BobH
So clearly it is fuel related because there are no reports of #1 cylinder failing.
Repeated pre-detonation over time stressing the marginal cylinder strength?
BobH, I think you are quite close. Yesterday in the club I shared the images with our clubs experts. One of them is main importeur of various engines from far east. He told me exactly what you said. Overstress because of either advanced ignition or too much fuel in the chamber or combination of both. He has in the past certain engine models being returned with a blown cylinder head. The engine was in fact quite nice but lightly build. It would crack at the weakest spot. They have retarded the ignition for all the remaining stock and they did not hear any problems after that.
Retarding the ignition or higher octane fuel might certainly improve the situation. There will be some power loss in retarding but quite frankly, I already had it difficult to reduce the max rpm with h needle. Everytime I reduced top end a little, it would start with misfiring. So, retarding might solve that also.
Old 04-10-2016, 07:21 AM
  #585  
johnhi
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Originally Posted by scubaozy
They have retarded the ignition for all the remaining stock and they did not hear any problems after that.
Retarding the ignition or higher octane fuel might certainly help.
This all sounds plausible. Can I ask how I would retard the ignition, which direction would I need to turn the sensor?

I'm still waiting for the replacement cylinder from HobbyPlastic, here's the picture of the cracked #2 cylinder which I didn't share earlier.

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Old 04-10-2016, 07:29 AM
  #586  
aquaskiman
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Originally Posted by johnhi
This all sounds plausible. Can I ask how I would retard the ignition, which direction would I need to turn the sensor?

I'm still waiting for the replacement cylinder from HobbyPlastic, here's the picture of the cracked #2 cylinder which I didn't share earlier.

I see you have a Morris carb on it. How did that work?
Old 04-10-2016, 07:34 AM
  #587  
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Originally Posted by johnhi
This all sounds plausible. Can I ask how I would retard the ignition, which direction would I need to turn the sensor?
When you are facing the engine, moving right will advance, moving left will retard. Wow, The crack is so exactly at the same place!
Old 04-10-2016, 08:02 AM
  #588  
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Originally Posted by BobH
For hydra lock to be an issue for this engine one would need to turn it over using an electric starter when experiencing a flooded cylinder. Now if you pull the engine though before hand, making sure your engine is working properly you won't/ can't have hydra lock.
So clearly it is fuel related because there are no reports of #1 cylinder failing.
Repeated pre-detonation over time stressing the marginal cylinder strength? Just looking at possible issues here. Not trying to say that's the real cause.
I will use higher octane fuel just to be sure. Can't hurt.
I have seen and have experienced hydra lock in Saito gas engines during hand starting. On my FG36 I over choked the engine by drawing more fuel into the carburetor by doing 6 flips of the prop, instead of 4 during the first start of the day. From the time it took me to return the choke extension tool to my tool box and turning the ignition switch on, I had hydra lock. I knew it was hydra lock because the prop would not flip through the compression stroke, it bounced back in the opposite direction of prop rotation. I tried a total of 3 flips of the prop by hand, same result, the prop would not pass through the compression stroke. I began to remove the spark plug cap so I could remove the plug and clear the hydra lock. A fellow club member came over to where I was working and asked what I was doing, I said I was removing the spark plug to clear a hydra lock and explained to him what had happened. His response was, you don't have to remove the plug, all you have to do is hold the two prop blades and force the engine through the compression stroke two or more times to clear the fuel from the cylinder. I told him he didn't have a clue how to properly clear a hydra lock, and his method would more than likely cause damage to the engine.

I wonder if the FG60 owners that have experienced cylinder head failure have had hydra lock and didn't recognize it as hydra lock during hand starting when the prop would not pass through the compression stroke two or more times? Then not correctly clearing the hydra lock?
Old 04-10-2016, 08:04 AM
  #589  
johnhi
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Originally Posted by aquaskiman
I see you have a Morris carb on it. How did that work?
Much esier to tune and hand start with a proper choke.
john
Old 04-10-2016, 08:51 AM
  #590  
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I never use a starter on any of my engines. Granted I only have this engine, a DLE 30 and a DLE 55RA. If they don't start by hand flipping, there is something wrong, and a starter is unlikely to solve the problem.
Flooding 2 Strokes is not as prevalent I find, but too much choke will do it. Doing it on an inverted 4 stroke is much more achievable
Old 04-10-2016, 08:55 AM
  #591  
aquaskiman
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I am not buying the hydro lock theory. A glow motor can siphon fuel when the engine is not running if throttle is open, these engines will not put fuel into the engine unless the engine is turning over.
Old 04-10-2016, 09:41 AM
  #592  
BobH
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Of course you can have hydra lock when attempting starting. To much fuel in the cylinder. You can clear it by removing the plug or turning the engine backwards. In most cases either will work.
BUT we are not talking about starting.. we are talking about running engines. Lots different situation.
As for rapid temperature changes that's good and bad news..
The good news.. it means the cylinder is transferring heat to the fins and off the engine.
The bad news.. It also means there is relatively thin material to aid in this efficient heat transfer.
Some where there is a balance.
Old 04-10-2016, 11:09 AM
  #593  
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Originally Posted by ForcesR

I wonder if the FG60 owners that have experienced cylinder head failure have had hydra lock and didn't recognize it as hydra lock during hand starting when the prop would not pass through the compression stroke two or more times? Then not correctly clearing the hydra lock?
The cylinders fail during flight not starting.
Old 04-10-2016, 11:42 AM
  #594  
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Well...interesting to me that it appeared to happen at mid-throttle range (if I read the post properly?). I wonder if the lower cylinders are actually firing at that lower rpm, my no.3 cylinder appears to drop out at idle and chimes in with higher rpm. If the cylinder is not firing could fuel build up? Wouldn't it drain when the valves open? Perhaps not, certainly not on the compression stroke.
I guess I'm just wondering if it's an overfuelling problem on the lower cylinders at lower rpm's? At lower rpm's it can be difficult to tell if a cylinder has dropped out, other than a drop in temp on that cylinder.
Old 04-10-2016, 12:44 PM
  #595  
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Originally Posted by johnhi
The cylinders fail during flight not starting.
If you have a hydra lock during the starting procedure and force the prop through the compression stroke without clearing the hydra lock, the cylinder head is usually stressed beyond what it is engineered to handle. Over stressing a cylinder head usually results in hair line cracking. This hair line cracking will not be noticed or immediately affect the engines performance after it starts. The crack will slowly spread over time as the engine is operated due to normal combustion pressures. The crack will continue spreading throughout the cylinder head to the point where cylinder head has become so weakened due to the spreading of the crack that the cylinder head will fracture and fail, which is usually in flight. This is actually what happens in full size radial engines when a hydra lock condition is ignored and not properly cleared.
I have seen this happen many times in the 37 years I have been working in the aerospace industry. These RC radial engines are really no different than their big brother full size radials when it comes to hydra locking and cylinder head fracturing.
Old 04-10-2016, 02:22 PM
  #596  
BobH
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To our knowledge no one has reported ever having a hydra lock on this engine that they forced through.
I'm not saying that hasn't happened but why don't we hear of these issues with other radial engines? We just don't which leads me to believe that is a repeated but inaccurate cause in this case.
Old 04-10-2016, 09:05 PM
  #597  
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Could the great heat fluctuations cause the tappets to go out of adjustment? Maybe we're going to have to stay after them often?
Dan

Had mine quite a while now and still havn't run her
Old 04-11-2016, 07:28 AM
  #598  
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I've had mine about a year and have only run through about a gal.of fuel on a test stand. I bought it on sale for a future project,probably a mistake with the warranty running out.
Old 04-11-2016, 08:00 AM
  #599  
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A fellow flier took a quick video of my P-47 with the FG-60 this past weekend. Thought I would share.
https://m.youtube.com/watch?v=Ylt_7yfTzl0
Old 04-11-2016, 08:16 AM
  #600  
marksp
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Originally Posted by cathurga
... THis engine was supposed to have received the upgraded inlet and bushing scenario, but since I bought mine from rcjapan, I don't know whether I got these or not. Are all the failures happening on the new and the old version, or is it just one of the two?

...

Regards to all,
Andy
FWIW, As mentioned earlier, after engineering the fixes (inlet manifold re-design, Conrod bushing/polishing, etc.) for the FG-84R3 and FG-33R3, Ray licensed the design to Saito. Saito elected to leave 84 & 33 as is, but did in fact incorporate into the FG-60R3. Unfortunately, as implemented, the manifold on FG-60R3 is too large by volume, per Ray.

He offers a mod which corrects (reduces) this and modifies the carb to match. Again, I'm not asserting that this is the issue contributing to the failures and I'm certainly no thermal/hydro/mech engineer, and I'm not promoting anyone throw more $$$ after already buying a premium engine. Having said that, both my FG-33R3 & FG-60R3 w/RE mods seem to run fine. Morgan Cool Power mixed 15:1, 1 oz /Seafoam/gal, non-ethanol. RCExcl plugs.

Lastly, I may be wrong, but I don't think there have been any running changes on any of the FG radials, so they should all be the same irrespective of when or what channel purchased from.

Your mileage may vary....

Cheers

Last edited by marksp; 04-11-2016 at 08:25 AM.

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