NGH 38CC 4 stroke
#1326
Senior Member
Using this STATIC THRUST CALCULATOR we get the following:
An 18" prop would be "scale" for a 1/4 scale J-3 Cub.
My suggesting would be to use an 18x6 since speed is not what you will be looking for with a J-3 Cub. IF you could turn an 18X8 at near 8.000 RPM, you would be generating 3 HP, but I think that's a bit optimistic for that engine.
#1327
Join Date: Feb 2013
Location: BlenheimMarlborough, NEW ZEALAND
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On a 18 x 8 prop you should be getting approx. 7000-7300 rpm going by the performance I have seen in my GF-38's. Other's figures may differ, but it should be somewhere near than.
#1328
I am getting 7400 RPM with a 18-6 classic prop. I noticed when i change to a good synthetic oil rpm went up.
One thing i did was add a check valve or PVC valve in the tube going to the manifold and it seems to stop oil form the crankcase entering the engine but still allows fuel to enter the crankcase for lubrication.
One thing i did was add a check valve or PVC valve in the tube going to the manifold and it seems to stop oil form the crankcase entering the engine but still allows fuel to enter the crankcase for lubrication.
#1329
Senior Member
I am getting 7400 RPM with a 18-6 classic prop. I noticed when i change to a good synthetic oil rpm went up.
One thing i did was add a check valve or PVC valve in the tube going to the manifold and it seems to stop oil form the crankcase entering the engine but still allows fuel to enter the crankcase for lubrication.
One thing i did was add a check valve or PVC valve in the tube going to the manifold and it seems to stop oil form the crankcase entering the engine but still allows fuel to enter the crankcase for lubrication.
#1330
when I was testing different props for my black horse fieseler storch I got this numbers.
bmabula 18x8 7300rpm 4.9kg
master 20x10 5700rpm 4.8kg
xoar 20a 3d 5300rpm 4.5kg
20x8 carbon 5900rpm 5.1kg
18x8 carbon 7000rpm 3.2kg
Max thrust with carbon 20x8. And with that prop the plane flies fine. The plane is 2.85m vs. and 7.9 kg
video
https://youtu.be/74Vl5FiWPXQ?t=5m33s
bmabula 18x8 7300rpm 4.9kg
master 20x10 5700rpm 4.8kg
xoar 20a 3d 5300rpm 4.5kg
20x8 carbon 5900rpm 5.1kg
18x8 carbon 7000rpm 3.2kg
Max thrust with carbon 20x8. And with that prop the plane flies fine. The plane is 2.85m vs. and 7.9 kg
video
https://youtu.be/74Vl5FiWPXQ?t=5m33s
Last edited by tyor; 11-19-2015 at 04:42 PM.
#1333
Join Date: Sep 2007
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when I was testing different props for my black horse fieseler storch I got this numbers.
bmabula 18x8 7300rpm 4.9kg
master 20x10 5700rpm 4.8kg
xoar 20a 3d 5300rpm 4.5kg
20x8 carbon 5900rpm 5.1kg
18x8 carbon 7000rpm 3.2kg
Max thrust with carbon 20x8. And with that prop the plane flies fine. The plane is 2.85m vs. and 7.9 kg
video
https://youtu.be/74Vl5FiWPXQ?t=5m33s
bmabula 18x8 7300rpm 4.9kg
master 20x10 5700rpm 4.8kg
xoar 20a 3d 5300rpm 4.5kg
20x8 carbon 5900rpm 5.1kg
18x8 carbon 7000rpm 3.2kg
Max thrust with carbon 20x8. And with that prop the plane flies fine. The plane is 2.85m vs. and 7.9 kg
video
https://youtu.be/74Vl5FiWPXQ?t=5m33s
#1334
My Feedback: (47)
Just ran my engine for the first time!
So, I jumped on the bandwagon and bought this engine during HK's cyber week sale. Reading this thread helped me get the engine set up right. Thanks to all the previous posts on these tips!!
I've added gaskets on the carb, blue lock tighted almost every bolt, and slid the timing pick up all the way CCW,FLA.
She started right up! Ran it for about 45 minutes now, and I have to say, this engine is running beautifully. It's a bit of a shaker, but hasn't quit on me yet...
I'm using a MA classic 18×6 and just after 45 minutes run time, I'm getting reliable idle down to 1700, and top end is hitting 8300! I'm using Trufuel 4 cycle, with 25:1Sthil synthetic 2 cycle oil.
If anyone is on the fence, BUY IT!
-Richie
I've added gaskets on the carb, blue lock tighted almost every bolt, and slid the timing pick up all the way CCW,FLA.
She started right up! Ran it for about 45 minutes now, and I have to say, this engine is running beautifully. It's a bit of a shaker, but hasn't quit on me yet...
I'm using a MA classic 18×6 and just after 45 minutes run time, I'm getting reliable idle down to 1700, and top end is hitting 8300! I'm using Trufuel 4 cycle, with 25:1Sthil synthetic 2 cycle oil.
If anyone is on the fence, BUY IT!
-Richie
#1335
Join Date: Jun 2011
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Try running a larger prop, something more like a 19*8. I think this engine is happier at lower revs and vibes will be less of an issue, and going by Tyor's results you will get way more pull running a 19 or 20" prop. I started with a HK beech 18*8, when the weather improves I'll be trying 19*8 and 20*8. I expect to get just as good, or better, performance and less noise.
#1340
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So, I jumped on the bandwagon and bought this engine during HK's cyber week sale. Reading this thread helped me get the engine set up right. Thanks to all the previous posts on these tips!!
I've added gaskets on the carb, blue lock tighted almost every bolt, and slid the timing pick up all the way CCW,FLA.
She started right up! Ran it for about 45 minutes now, and I have to say, this engine is running beautifully. It's a bit of a shaker, but hasn't quit on me yet...
I'm using a MA classic 18×6 and just after 45 minutes run time, I'm getting reliable idle down to 1700, and top end is hitting 8300! I'm using Trufuel 4 cycle, with 25:1Sthil synthetic 2 cycle oil.
If anyone is on the fence, BUY IT!
-Richie
I've added gaskets on the carb, blue lock tighted almost every bolt, and slid the timing pick up all the way CCW,FLA.
She started right up! Ran it for about 45 minutes now, and I have to say, this engine is running beautifully. It's a bit of a shaker, but hasn't quit on me yet...
I'm using a MA classic 18×6 and just after 45 minutes run time, I'm getting reliable idle down to 1700, and top end is hitting 8300! I'm using Trufuel 4 cycle, with 25:1Sthil synthetic 2 cycle oil.
If anyone is on the fence, BUY IT!
-Richie
I have been running this motor in a great planes Waco. I have not made any adjustments or changed any gaskets on the motor and it seems to run fine. What does adjusting the timing do for you? I am running a cf Biela 18x8 and getting about 7900 rpm with a nice idle.
Thanks,
Bob
#1341
My Feedback: (11)
GUYS, Timing adjustments now I am not sure is need it for the new engines sold I think after September.
But I am not 100% . I know that NGH may use the 40 BTDC CDI insted of the regular 30 and sensor at 40-45BTDC.
No way to know what you may have. Before you do any adjustments mark the sensor position and move it one way or another.
Adrian
But I am not 100% . I know that NGH may use the 40 BTDC CDI insted of the regular 30 and sensor at 40-45BTDC.
No way to know what you may have. Before you do any adjustments mark the sensor position and move it one way or another.
Adrian
#1342
Join Date: Jun 2011
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My engine was a nasty biter on starting before I retarded the ignition - maybe it has lost a couple of hundred RPM off the top but it made it a much nicer engine. It was bought earlier in the year though!
#1344
Senior Member
#1345
Senior Member
Richie,
I have been running this motor in a great planes Waco. I have not made any adjustments or changed any gaskets on the motor and it seems to run fine. What does adjusting the timing do for you? I am running a cf Biela 18x8 and getting about 7900 rpm with a nice idle.
Thanks,
Bob
I have been running this motor in a great planes Waco. I have not made any adjustments or changed any gaskets on the motor and it seems to run fine. What does adjusting the timing do for you? I am running a cf Biela 18x8 and getting about 7900 rpm with a nice idle.
Thanks,
Bob
#1346
Join Date: Feb 2013
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Yes, I am very interested in this module. It does seem that the original module does not operate on a performance curve that would give smooth idle and easy start and then advance to give full rpm. Some of us have sacrificed top-end rpm for a little better idle and start.
#1347
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Richie,
I have been running this motor in a great planes Waco. I have not made any adjustments or changed any gaskets on the motor and it seems to run fine. What does adjusting the timing do for you? I am running a cf Biela 18x8 and getting about 7900 rpm with a nice idle.
Thanks,
Bob
I have been running this motor in a great planes Waco. I have not made any adjustments or changed any gaskets on the motor and it seems to run fine. What does adjusting the timing do for you? I am running a cf Biela 18x8 and getting about 7900 rpm with a nice idle.
Thanks,
Bob
#1348
#1349
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#1350
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Oops rechecked at at the field yesterday and was getting 7600 approx. and the prop is 18x6 not 18x8.
I just bought another one of these motors and can not figure out what to put it in. Any ideas? It's tough because the motor is so long, like 172mm from back of motor to washer.