O.S. GF40 4st gas
07-29-2013, 02:02 PM
#76
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Location: Toronto, ON, CANADA
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RE: O.S. GF40 4st gas
Hi,
Last weekend run my OS GF40 on the 90" wingspan plane.
4 flights over 17 min each.
I put carb settings to manufactue settings (a bit too rich).
Run it on 20:1 mixture what is left from my SAITO engines although it is recommended to use 30:1 or even 40:1 depend on oil quality.
Engine performed very well on verticals and quite good duging horizontal flight at very low RPM.
Flown with APC 18x8W. Static thrust on the ground 8.2kg (18.0 pounds).
I am planning to lean low needle a bit once brake-in finished at high RPM (in the flights).
The sound of the engine when plane is passing by is exact as from the real size Cub plane.
Quite satisfied with results.
Last weekend run my OS GF40 on the 90" wingspan plane.
4 flights over 17 min each.
I put carb settings to manufactue settings (a bit too rich).
Run it on 20:1 mixture what is left from my SAITO engines although it is recommended to use 30:1 or even 40:1 depend on oil quality.
Engine performed very well on verticals and quite good duging horizontal flight at very low RPM.
Flown with APC 18x8W. Static thrust on the ground 8.2kg (18.0 pounds).
I am planning to lean low needle a bit once brake-in finished at high RPM (in the flights).
The sound of the engine when plane is passing by is exact as from the real size Cub plane.
Quite satisfied with results.
07-29-2013, 02:21 PM
#77
RE: O.S. GF40 4st gas
ORIGINAL: akouzmit
Hi,
Last weekend run my OS GF40 on the 90'' wingspan plane.
4 flights over 17 min each.
I put carb settings to manufactue settings (a bit too rich).
Run it on 20:1 mixture what is left from my SAITO engines although it is recommended to use 30:1 or even 40:1 depend on oil quality.
Engine performed very well on verticals and quite good duging horizontal flight at very low RPM.
Flown with APC 18x8W. Static thrust on the ground 8.2kg (18.0 pounds).
I am planning to lean low needle a bit once brake-in finished at high RPM (in the flights)
The sound of the engine when plane is passing by is exact as from the real size Cub plane.
Quite satisfied with results.
Hi,
Last weekend run my OS GF40 on the 90'' wingspan plane.
4 flights over 17 min each.
I put carb settings to manufactue settings (a bit too rich).
Run it on 20:1 mixture what is left from my SAITO engines although it is recommended to use 30:1 or even 40:1 depend on oil quality.
Engine performed very well on verticals and quite good duging horizontal flight at very low RPM.
Flown with APC 18x8W. Static thrust on the ground 8.2kg (18.0 pounds).
I am planning to lean low needle a bit once brake-in finished at high RPM (in the flights)
The sound of the engine when plane is passing by is exact as from the real size Cub plane.
Quite satisfied with results.
Did you measure the thrust with a fish scale? What was the peak rpm?
07-29-2013, 06:43 PM
#78
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RE: O.S. GF40 4st gas
ORIGINAL: AeroFinn
Congrats for the maiden!
Did you measure the thrust with a fish scale? What was the peak rpm?
ORIGINAL: akouzmit
Hi,
Last weekend run my OS GF40 on the 90'' wingspan plane.
4 flights over 17 min each.
I put carb settings to manufactue settings (a bit too rich).
Run it on 20:1 mixture what is left from my SAITO engines although it is recommended to use 30:1 or even 40:1 depend on oil quality.
Engine performed very well on verticals and quite good duging horizontal flight at very low RPM.
Flown with APC 18x8W. Static thrust on the ground 8.2kg (18.0 pounds).
I am planning to lean low needle a bit once brake-in finished at high RPM (in the flights)
The sound of the engine when plane is passing by is exact as from the real size Cub plane.
Quite satisfied with results.
Hi,
Last weekend run my OS GF40 on the 90'' wingspan plane.
4 flights over 17 min each.
I put carb settings to manufactue settings (a bit too rich).
Run it on 20:1 mixture what is left from my SAITO engines although it is recommended to use 30:1 or even 40:1 depend on oil quality.
Engine performed very well on verticals and quite good duging horizontal flight at very low RPM.
Flown with APC 18x8W. Static thrust on the ground 8.2kg (18.0 pounds).
I am planning to lean low needle a bit once brake-in finished at high RPM (in the flights)
The sound of the engine when plane is passing by is exact as from the real size Cub plane.
Quite satisfied with results.
Did you measure the thrust with a fish scale? What was the peak rpm?
Yes, the static trust has been measured with electronic fish scale of up to 50 LB max.
It's provide very accurate measurement. They are available at Canadian Tire store here in Canada as well as at any fishing stores.
I do not re-call exactly the RPM, but if I remember correctly it was around 8150-8250 RPM.
The prop was wide blade APC 18x8W.
07-29-2013, 10:36 PM
#79
RE: O.S. GF40 4st gas
ORIGINAL: akouzmit
-
Yes, the static trust has been measured with electronic fish scale of up to 50 LB max.
It's provide very accurate measurement. They are available at Canadian Tire store here in Canada as well as at any fishing stores.
I do not re-call exactly the RPM, but if I remember correctly it was around 8150-8250 RPM.
The prop was wide blade APC 18x8W.
ORIGINAL: AeroFinn
Congrats for the maiden!
Did you measure the thrust with a fish scale? What was the peak rpm?
ORIGINAL: akouzmit
Hi,
Last weekend run my OS GF40 on the 90'' wingspan plane.
4 flights over 17 min each.
I put carb settings to manufactue settings (a bit too rich).
Run it on 20:1 mixture what is left from my SAITO engines although it is recommended to use 30:1 or even 40:1 depend on oil quality.
Engine performed very well on verticals and quite good duging horizontal flight at very low RPM.
Flown with APC 18x8W. Static thrust on the ground 8.2kg (18.0 pounds).
I am planning to lean low needle a bit once brake-in finished at high RPM (in the flights)
The sound of the engine when plane is passing by is exact as from the real size Cub plane.
Quite satisfied with results.
Hi,
Last weekend run my OS GF40 on the 90'' wingspan plane.
4 flights over 17 min each.
I put carb settings to manufactue settings (a bit too rich).
Run it on 20:1 mixture what is left from my SAITO engines although it is recommended to use 30:1 or even 40:1 depend on oil quality.
Engine performed very well on verticals and quite good duging horizontal flight at very low RPM.
Flown with APC 18x8W. Static thrust on the ground 8.2kg (18.0 pounds).
I am planning to lean low needle a bit once brake-in finished at high RPM (in the flights)
The sound of the engine when plane is passing by is exact as from the real size Cub plane.
Quite satisfied with results.
Did you measure the thrust with a fish scale? What was the peak rpm?
Yes, the static trust has been measured with electronic fish scale of up to 50 LB max.
It's provide very accurate measurement. They are available at Canadian Tire store here in Canada as well as at any fishing stores.
I do not re-call exactly the RPM, but if I remember correctly it was around 8150-8250 RPM.
The prop was wide blade APC 18x8W.
Have you tried, by ever chance, any 19x8 prop?
07-30-2013, 02:59 AM
#80
RE: O.S. GF40 4st gas
I have a good 6 10min flights on mine and I am using a 18x8 xoar at 1770rpm. I will lean it out after 10 flights and go to a 19x8 xoar. Then after another 10 flights I will try the 16x10 – 3 blade.
Engine is running very good now. I am putting a ball valve on the fuel line so I don’t have to pinch the line after flights.
TB
Engine is running very good now. I am putting a ball valve on the fuel line so I don’t have to pinch the line after flights.
TB
07-30-2013, 07:31 AM
#82
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RE: O.S. GF40 4st gas
Regarding usage of 19x8 !
Answer: please, notice that I am using WIDE blade prop: APC 18x8W.
This one is loading engine as 19x8 with normal width blades.
If to go for 20x7/8 then RPM is going down and engine is performing not at his best efficiency spot thus I am avoiding to go this way.
I believe APC 18x8W is the best selection for GF40 if you want to be in sweet spot of performance, engine wearing and reliablility in a long run.
For slow flying planes like Cub 20x7 is probably a good selection, but then you least likely to run engine at full throttle as you want to maintain scale behavior for your Cub.
For sport flying I feel 18x8W is the best.
I am not 3D guy, thus I do not have experience and recommendation for prop selection in this area.
Andrei.
Answer: please, notice that I am using WIDE blade prop: APC 18x8W.
This one is loading engine as 19x8 with normal width blades.
If to go for 20x7/8 then RPM is going down and engine is performing not at his best efficiency spot thus I am avoiding to go this way.
I believe APC 18x8W is the best selection for GF40 if you want to be in sweet spot of performance, engine wearing and reliablility in a long run.
For slow flying planes like Cub 20x7 is probably a good selection, but then you least likely to run engine at full throttle as you want to maintain scale behavior for your Cub.
For sport flying I feel 18x8W is the best.
I am not 3D guy, thus I do not have experience and recommendation for prop selection in this area.
Andrei.
08-11-2013, 03:28 AM
#83
I have little over a gallon threw my number one engine and it is running solid. No issues since I put the ball valve on the fuel line. I flip start it with the same ease as my DLE. I am still running the 18x8 Xoar and getting 8000 RPM, I tried the 19x10 and did not like it. I will put another gallon or so threw it then try the 3-blade. I am leaning it out very slowly. I turned the H valve in just enough to see it move.
Qestion, are you guys adjusting the valves on the head at all? On my saitos I did that after a few flights.
TB
Qestion, are you guys adjusting the valves on the head at all? On my saitos I did that after a few flights.
TB
08-11-2013, 02:39 PM
#84
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TB I see that you are using a fuel shut off. I fly nothing but gas and I always just have a throttle cut switch that completely closes the throttle to shut mine off. Can you not do that with this engine. I am thinking of putting it in a H9 30 cc p47.
08-19-2013, 06:41 PM
#85
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The good experience with GF40 didn't last long . . . .
This happened just after 1.5 hours in operation: https://vimeo.com/72599357
The rocker "bushing" wear out completely!!!
OS is offering free replacement parts, but silent on issue . . .
Anybody flown planes with GF40 for over 2 hours in total?
I am wondering if GF40 owners came across the same issue?
In the last flight I have noticed that plane is not performing well on verticals.
The acceleration from the idle to max rpm become not smooth as it was before.
I have opened rockers cover and discovered . . . surprising for OS famous quality issue.
Any comments from GF40 owners?
Thank you,
Andrei K.
This happened just after 1.5 hours in operation: https://vimeo.com/72599357
The rocker "bushing" wear out completely!!!
OS is offering free replacement parts, but silent on issue . . .
Anybody flown planes with GF40 for over 2 hours in total?
I am wondering if GF40 owners came across the same issue?
In the last flight I have noticed that plane is not performing well on verticals.
The acceleration from the idle to max rpm become not smooth as it was before.
I have opened rockers cover and discovered . . . surprising for OS famous quality issue.
Any comments from GF40 owners?
Thank you,
Andrei K.
08-20-2013, 05:50 AM
#87
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Location: Toronto, ON, CANADA
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Yes, please open and chech rockers for excess of freedom on the axle.
Att the same time you may adjust space between locker head and valve head.
Your info is telling me that I may have badly manufacturing parts, but not design flaw.
I hope replacement parts will fix issue for many hours of operation.
Att the same time you may adjust space between locker head and valve head.
Your info is telling me that I may have badly manufacturing parts, but not design flaw.
I hope replacement parts will fix issue for many hours of operation.
08-20-2013, 11:09 AM
#89
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As I mentioned in one of my first reports the area under rocker cover is VERY well lubricated. I have removed oil before taking video.
Sound you are joking regarding inverted installation :-) as engine was running fine for the first hour and was producing expected RPM and expected trust at the ground.
OS replied they do not have rockers stock at this time ...
I also found out that rockers doesn't have any bushing, but hardened rocker metal by hardened rocker axle are running against each other. The same for Saito rockers.
May be metal hardening wasn't done well for the parts in my engine.?
08-20-2013, 12:59 PM
#90
Andrei, I watched your video. Man that sucks and now I'm worried. I have two of these I want to put in my Ziroli B-25. I am test running one in my cub to see how it does and if it holds up. I may pop off the cover and look at the rocker. If it does what yours did I will send the new engine back and can them. But I'm holding hope out that they are true OS quality engines.
TB
TB
08-20-2013, 01:06 PM
#91
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Andrei, I watched your video. Man that sucks and now I'm worried. I have two of these I want to put in my Ziroli B-25. I am test running one in my cub to see how it does and if it holds up. I may pop off the cover and look at the rocker. If it does what yours did I will send the new engine back and can them. But I'm holding hope out that they are true OS quality engines.
TB
TB
OS replied they didn't see it yet from the other owners.
Believe me I handle this engine with love :-) and I know how to handle these 4-stoke gas engines.
I have good expertise on SAITO 14/21/30/36 4-stroke gas engines and this issue with OS engine quite surprised me.
08-20-2013, 07:32 PM
#93
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==================================================
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I think many people (as well as OS custom support people) do not understand that harden steel material, which wear out is actually went through the engine cylinder and piston . . . as well as all the bearings on the way as the fuel mixture is traveling through under rocker cover before entering the chamber. It is done for good rocker parts lubrication.
Due to this fact all wear material went the same way damaging cylinder, piston and some other parts . . . this is the real issue for engine.
-------------------------------------
I think many people (as well as OS custom support people) do not understand that harden steel material, which wear out is actually went through the engine cylinder and piston . . . as well as all the bearings on the way as the fuel mixture is traveling through under rocker cover before entering the chamber. It is done for good rocker parts lubrication.
Due to this fact all wear material went the same way damaging cylinder, piston and some other parts . . . this is the real issue for engine.
08-20-2013, 08:26 PM
#94
Thread Starter
Just curious, what type and how much oil were you useing in the fuel? Mine is still clean under the rocker cover, with plenty of oil. I'm running Stihl HP ultra at 30-1.
Mark.
Mark.
Last edited by MKnutson; 08-20-2013 at 08:28 PM.
08-21-2013, 04:32 AM
#95
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On all my Saito engines: 14/21/30/36 and this OS GF40 I am using 20:1 Evolution Oil.
In fact I do not see such wear on Saito engines, wich I run for much longer.
08-21-2013, 08:39 PM
#96
Thread Starter
Just opened the valve cover for a quick check, and it's very clean and oily with no slop on the rocker shafts. I've also got a Saito 57T and on that engine I worry about the LACK of oil on the cams and rockers. I can see wear in its future.
10-16-2013, 03:35 AM
#98
Update on my engine. It is running great with no issues. I did have one dead stick on take off and the only thing I can think of is that it was a very hot day, 107 and the manual says do not fly when the temp is over 104, so who knows. But it is running great and starts every time with a flip start. I sent one of my engines to Kelvin at Keleo Creations so he can make a pits style rape around muffler for it. He will be making a temple so he can offer this muffler for the OS GF40 4S. I should have it back soon.
TB
TB
10-22-2013, 03:31 AM
#99
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So far I am at 7600 with a 17x8-3 blade xoar prop with this engine but I am still thinking it is rich. I am at 1-1/2 turns out on both low and high needles.... engine has great transition but the plug is still black when checked.... oil is 32:1 lawnboy ashless regular 89 octane fuel.......... should I keep tweeking the high needle until plug is chocolate or leave it as is?
cant wait to maiden my 80" esm p-39 with this engine................ its about 20lbs rtf..............
cant wait to maiden my 80" esm p-39 with this engine................ its about 20lbs rtf..............
Last edited by indycustombikes; 10-22-2013 at 03:32 AM. Reason: spelling errors
10-22-2013, 03:47 AM
#100
I just leaned mine out yesterday and it is just under 8000 rpms with a 18-8 Xoar prop. I have over 30 flights on this engine, maybe 40, lost count a while back. Not sure on the plug thing. I would say if it is running good leave it and lean it out as you get more fuel threw it.
TB
TB