Redline 53H engine noise

[Suzuki_kid_1984]

Evening folks,

Took my rappy 50 out to the field today to flight trim and tune high speed needle. Had the engine sounding nice at around hover with back plate cool to touch and pinch test working (at idle).

However when dropping the stick from hover to idle the engine would stutter before settling to an idle. By stutter I mean it sounded like it was revving constantly before dropping to idle.

I thought the low end might be a bit lean (my thinking was that the engine was strugging to get fuel) but when slightly richening the low needle the idle would not keep itself consistent, and would eventually kill the engine. Before the adjustment the low needle was pretty much factory setting (flush with carb body)

Anyone else came across this?

[Tommy]

Sounds like really hot engine syndrome, get that high needle wound out

[Suzuki_kid_1984]

Thanks for the reply Tommy. Will give it a go. I thought it was running rich if anything as the heli was struggling to hover the higher the stick went, and the engine tone wasn't getting higher. Seemed to be a nice bit of smoke coming from the exhaust so thought it wasn't running lean.

I'm running on cool power 15% nitro, 17% oil. The engine manual suggested 20% oil so I wonder if that is causing the overheat?

[BASS 666]

mate if you have the old style carb on it you will never get it tuned redline made a new carb for them cause the old one draws in air and it runs lean. i shought know because i melted one of my engines. i bought a new engine and it had the sh.t carb on it again so i bought the new version carb and it runs like a clock.

[Suzuki_kid_1984]

Cheers for the heads up BASS. I just had a look on the web and people saying the new carb has a groove machined into the high needle tip. Checked mine and it has it. Is this the only way I can tell if I have the new type?

[Tommy]

Only read half your post! If the backplate was cool to touch then not sure?

If the engine requires high trim to idle then you need to wind down the idle valve and knowing TT engines some require considerable wind down, one and a half turns in some cases! Don't worry about it being flush with the body.

Then make sure the high is wound out enough.

The symptoms you describe could actually be pig rich as opposed to really lean, however usually that sounds like its way to hot. Could you notice the exhaust popping away on wind down?

[BASS 666]

mate i read all sorts of crap about the new and old and it was all crap. the only diff between my two carbs is on my new carb where the servo horn screws onto the shaft, the shaft has two grooves in it as well as two flat spots and the old one only has two flat spots. i dont really know how to tell the diff but i bought the engine of a guy on here and he put the new carb on it. i took the carb of it and put it on my brand new engine and i had it tuned in 20 mins. when i had the old carb on i was tuning it for weeks and i put a couple of threads on here for help as it was doing my head in. then i found out about the new carb and read up on it on all the other forums. thunder tiger are replacing the carbs for free if you can be botherd getting in touch with them..

[Suzuki_kid_1984]

Tommy I couldn't remember hearing any pop coming from the exhaust. Guess that would indicate being too rich?. I don't think it's running excessively lean as there is plenty of smoke at hovering throttle. BASS I'm going to contact Amerang and send mine just incase it's the old one, even if they send mine back atleast I'll know it's not the carb that's causing the problem.

[BASS 666]

Hanging RPM
If an engine is running lean then the RPM will “hang” (RPM stays high for a sec) is the throttle is
lowered to idle.
1. Hover the helicopter for 30 (somewhat) seconds
2. Land it and drop the throttle to idle
3. The RPM should drop immediately
4. If the RPM do not drop immediately but kinda “hangs” in a higher RPM before dropping
a. Too lean
Turn the Mixture control screw richer for 10 degrees counter-clockwise
b. Return to step 1
5. Does the RPM drop but the engine is smoking heavily and is sluggish?
a. Too rich
b. Turn the Mixture control screw leaner for 10 degrees clockwise
c. Return to step 1
6. When you got it right, turn it rich for 10 degrees and you are done....... hope this helps mate..

[Suzuki_kid_1984]

Spot on BASS, going to print this and take to the field next time. Hopefully this and the carb switch should cure my weird noise! Was sure it was a tuning issue but just needed a bit of guidance =]

[BASS 666]

Helicopter Engine Tuning
Tuning a helicopter engine is difficult because you cannot change settings on a running engine.
With this document I try to give you generic tips to tune your engine.
Important: Never activate your Governor or Throttle Jockey during tuning.
This may mask tuning errors.
2 needle engines
Most engines are 2 needle engines although 3 needles are gaining
popularity
.
The Idle screw is the small screw located within the throttle lever
(Mixture Control Screw) and the Main Needle is the bigger “screw” on
the other side (Needle Valve).
On a OS50 Hyper the Mixture Control screw is located at the same
side as the Needle Valve (Lower carburetor picture)
Tuning the Mixture Control Screw
This screw primarily controls the idle setting on the engine.
Idle settings must be set first. There are two way to do this:
1. Pinch test
2. Hanging RPM
Pinch Test
The pinch test is the First method to tune your Idle Setting:
1. Hover the helicopter for 30 (somewhat) seconds
2. Land it and drop the RPM to idle
3. Pinch the fuel line closed just before the carburetor (where the fuel line is connected to
the engine) and start counting the seconds
4. The engine should rev up and die because of lack of fuel.
5. If this is between 3 and 5 seconds its all right
a. Sooner? Too lean
Turn the Mixture control screw richer for 10 degrees counter-clockwise
b. Longer then 5 seconds? Too rich
Turn the Mixture control screw leaner for 10 degrees clockwise
6. Return to step 1 until you got it right
WWW.Jupiter-Venlo.nl
Document title: Helicopter Engine Tuning
2/6 23-5-2008
Hanging RPM
If an engine is running lean then the RPM will “hang” (RPM stays high for a sec) is the throttle is
lowered to idle.
1. Hover the helicopter for 30 (somewhat) seconds
2. Land it and drop the throttle to idle
3. The RPM should drop immediately
4. If the RPM do not drop immediately but kinda “hangs” in a higher RPM before dropping
a. Too lean
Turn the Mixture control screw richer for 10 degrees counter-clockwise
b. Return to step 1
5. Does the RPM drop but the engine is smoking heavily and is sluggish?
a. Too rich
b. Turn the Mixture control screw leaner for 10 degrees clockwise
c. Return to step 1
6. When you got it right, turn it rich for 10 degrees and you are done.
Tuning the High Speed/Main Needle
Step 1
Hover the helicopter and check if the RPM stays stable and the smoke is “normal”.
•
Is the RPM increasing after a while? Then its too lean.
o
Land the helicopter and turn the Main Needle 3 clicks counter-clockwise (richer)
•
Is the engine loosing power after a while? Then its too lean.
o
Land the helicopter and turn the Main Needle 3 clicks counter-clockwise (richer)
•
It the engine sluggish and not getting up to speed? Too rich.
o
Land the helicopter and turn the Main Needle 3 clicks clockwise (leaner).... print it all mate it helps a bit when your stuck..

[Suzuki_kid_1984]

Thanks for your time with this BASS, very much appreciated. Will defo help next time i'm tuning!

[Raptormad2]

Hi have a redline 53 in my x50 had lots of funny tuning problems on the maiden just could not get it to run right had the redline plug fitted that came with the engine so changed
the glow plug for an os no8 and hey presto is now sweet as a nut ,but saying that my raptor 50 still has the redline plug fitted that came with the engine with no problems at all.

[Suzuki_kid_1984]

Hi Raptormad2,

I just checked to see which plug I'm currently running and it's the OS nr 8. I do have the TT R3 so I may give that a go. What fuel do you run? I'm using Cool power 15% Nitro but not sure if the 17% oil is a bit low. I know the redline's are high power engines so I'm not sure if I just need to up the nitro/oil content a bit?

[BASS 666]

if it helps kid im using 20% with an extra shim in the head ....