I will look for the middle needle. I was worried about the 2 turns , because my engine is new and just breaking in and did not want to run it lean. At 2 turns, the engine was not lean at all, though not slobbering rich. Do you think it would be OK to continue flying with this for a few more flights before leaning it out ?

Also, how hot should a heli engine get ? i found mine to be quite hot ! Since i am used to airplane engines, this seems to have gotten much hotter .
Is that normal too ?

I just do not want to do anything that would damage the engine/heli, since I have a long way to go and need this setup to perform for me for a few hundred flights
My goal is to hold an inverted hover at eye-level. Its still a dream, but will happen someday.
After all getting the 50 sized heli and being able to build and fly solo was also a dream that was realized.

TT53 does not have a 3rd needle like the new OS55 has. So there isn't much you can do about the midrange. It is usually a compromise between midrange and low end.

Considering that you are not using nitro, 2 turns sounds ok. But the engine should not be getting hot. When running rich, the backplate should be only a little above ambient temp. You should be able to keep your finger there comfortably for ever.

Not sure if all carbs supplied with the TT RL .53 has it, but the one we played with definitely had one.  And we found it after some scratching of our heads with the other two needles (while trying to get max rpm for 3D using 30% nitro) !

http://helifreak.com/showthread.php?t=97632
http://www.rcheliresource.com/review-thunder-tiger-redline-53-helicopter-engine/  (search for the word hidden)

The best tuning method I found for heli engines where you can touch the backplate is to be able to keep the finger there for 3 to 5 seconds.  At this point, the engine is not too rich or too lean.  For break-in (where you are now), you should be able to keep to finger there forever and it should feel very warm (not hot), like Rajesh said.  If this is satisfied, then do not worry about the number of turns, it is whatever it is.

BTW, you have to check the backplate temperature as soon as you land (from hovering or flying) and go to idle rpm, as the temperature seems to seep in and rise soon afterwards. And make sure you touch the backplate itself, not any other place, as the reference temperatures are different for different parts of the engine. 

Thanks Anwar, Rajesh

I think my backplate temperature is good. Right after turning the engine off ( after a 3 minute hover ), i find that the backplate it not that hot and i can touch it for as long as i want. Though it does seem to get hot after a minute or so, even with the engine turned off. Looks like the temperature seeps in, as you said.

Now i have a few questions. Would be grateful of Anwar/Rajesh and any others who are experienced could help  me.

1. First I am not very sure if i have the rudder servo arm setup correctly. See picture of how i have it in Rate mode with rudder at neutral. Servo arm is perpendicular to the servo, but then, since the servo is mounted at an angle the arm is not perpendicular to the boom. Should this be made perpendicular to the boom instead ?

2.  I have the ball link mounted on one hole away from the end. Is this OK, or should i go for the last hole on the servo arm ?

3. When I have the engine idling at the lowest setting, ( ie if i reduce the trim further engine dies ), and if i leave the main blades, they start rotating very slowly. Looks like the clutch is not disengaging ? Is that how it should be ? or should the main blades not move at all at idle ?

4. I have had 4 tanks of fuel through y engine at rich setting, and I want to lean out the HSN a bit. Before that, i would like to know what is usually the best throttle I should plan on hovering.
Ie at midstick, pitch is around 5 degrees. Should the throttle be at 80 ? Whats the suggested throttle curve I should be using ?

5. When in a hover, at eye level, though i see 2 discs and not 3 , the main blades seem to be going all over the place. I mean it still makes one disc but its not smooth. Not ure how i can explain this here. Perhaps will post a video. What do you think the reason is ? Less headspeed ? or tracking ?

I guess thats it for now.
Thanks again.
-Gaurav

It is a terminology issue between us. If you call that 3rd needle what do you call the mid range needle in OS55HZ and the 90 engines ? The RL53 needle you are referring to sits opposite the low end needle. It provides a way to move the fuel injection point in the carb airflow (let's not consider the migration problem now, that is a separate issue). What effect this has is beyond my understanding. I don't know how this can be used to tune the midrange vs idle. Sounds like you fiddled with it and found some difference. Will be interested in knowing if you reached any understanding.

Can't remember all the details as this was almost a year ago, and I was helping a friend who was trying to do tic-tocs in one place. Tuning the main needle alone killed mid range performance, and finally we found this needle, and that did fix the mid-range issue. 

He has since sold that Trex 600 NP heli, and got the Align 600NSP with the .55 engine (a great deal from helipross.com). The power he gets on this new setup is just awesome !

The servo horn and the control rod should be at 90deg angle.


Typically 11-13mm from the servo centre works fine.


This is normal when engine is running rich. You need a faster idle to keep the engine running which engages the clutch. Once running in is over and you are able to lean the engine, you'll get a lower stable idle RPM. Clutch will be disengaged then.


The proper way to set the throttle curve is by measuring RPM. If you don't have a heli tach, you can use FFT analysis of the engine sound. My hovering throttle position is around 60% usually.


Are the blades snug in the grips ? Wooden blades are notorious for tracking issues. They might be perfect one flight and off the next. If you are using carbon blades, then check for play all the way from servos to the blade grips.

Was it to fix the gap due to a migrated needle or to move the fuel injection point ?

Must be the fuel injection point, as I don't recall the low needle moving by itself (I assume that is what you are calling the "migrated" needle).  I never really thought about the implications of this needle, as this was a two session affair (spent one day trying to figure this out for an hour or so, gave up, went home and read upon it, came back the next day and tried the middle needle thing, and it worked).  Never revisited this after that, and after the initial appreciation/hooplah about the RL .53, people who wanted high performance started getting other brands (YS, Novarossi, OS55 etc) again.

I want to check my main rotor RPM. Since i do not have a Heli tach, but I do have an optical airplane tachometer, how about fixing the tachometer vertically in the ground, underneath the main rotor and raising the RPM to just below hover and eyeballing the RPM ? I know it sounds dangerous, but perhaps thats the only way for me to know the RPM ?

Since I am new to helis I cannot really "know" the RPM, by just listening to the sound of the engine, but want to know the headspeed.

BTW, now that I have my heli going, i will be looking forward to setting up the gyro/tail servo properly, in rate mode with no drift, and then also in tuning the engine.
Expect to do this over the next few days.

It is the the "3rd needle" that migrates, not the low end.

TT53 still has its place as others are priced at a significant premium. I expected align 55 to be competitive, but hasn't been the case.

Gaurav,

You could zip tie the tach to frame or tail boom. If your tach has the capability to latch the peak RPM it'd be easier to just read it after it lands.

Was not aware of that. But I do remember that once we set it, he never mentioned having to touch it again.

I saw on the forums many people putting OS carbs in the RL53, but it also seems that there are two versions of the TT carb itself. 


You can try to keep the heli on a table with the skids tied down, adjust the pitch curve so that it does not lift off, and measure from underneath (VERY CAREFULLY, of course!).  But it is not a true test, and the loading effects of lift off are lost, but the variance should not be huge. 

Quick question on the tail servo installation. When i have the arm perpendicular to the control rod, tail slider is in the center of the shaft. and in rate mode the heli rotates to the left ( counter clockwise ) .
However there isnt any thread left on the control rod , at both ends to tighten further. Ie the links are fully tightened.

Any ideas on how to get this setup correctly ?

The raptor tail control rod comes with two pieces joined together. So just loosen that joint and move the individual linkage rods inside further ?

Mine seems to be just one long rod, with threads on both ends where the links attach... Maybe you saw a different Raptor version ?

This is the one I remember :

http://www.ronlund.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=heli&Product_Code=ACEPV0507&Category_Code=TITAN

It is possible that there are two mounting positions for the tail servo. Will wait for Rajesh to chip in

Also Rajesh, how did you come to know about the needle migration issue ?  Was that something you noticed after we started discussing on this thread, or were you aware of this issue from before ?

The titan has boom (well, almost) mounted servo.

Hope you have the horn side of the servo towards the nose.  You do end up using all the threads to get the right tail pitch. You should be pretty close to the required length unless you are running the belt loose. Try one more turn at both ends.

About the TT53, I was already aware of the issues and fixes since I have two of those engines.

I saw some people on the forums mounting the tail servo in the front to avoid exhaust build up, even on the Titan. 

Also the build manual seemed to show that the servo arm was closer to the tail than the nose   Saw the same on Titan pictures too.

Rajesh,
I have my tail servo mounted so that the horn side is towards the tail.
That is how it is shown in the manual ! And the tail servo faces towards the right.

Anwar, indeed there are 2 mounting options and hardware given for both, as you indicated. However I opted for the tail boom installation of servo, as that was simpler. I still have those 2 rods, including the bent one, but never used those.

Right now, the tail pitch control assembly links directly to the servo mounted on the boom, through one straight rod.

BTW the Raptor is much more stable than the mini Titan. In fact feels easier too. The first day I was a little nervous, but now i seem to love it ! .
Hope to start doing forward flights on Sunday !

I'm out of station right now, so can't take a look at my helis to confirm. But if you turn the servo around, looks like your problem will be solved ?

I have had around 10 flights on my heli now. Mostly hoverings and slow flights .
I have leaned out the high speed needle a bit and the engine seems to perform more smoothly.
I do have a bunch of questions . Looking out to Anwar/RotorZone to assist :

1. I havent yet tweaked the Low speed needle yet. On a brand new engine, is this something that is usually needed ? On airplane engines we do not touch this (mostly) on new engines and the factory setting is good enough.
In my case of TT 53RL, i think that the low speed needle is rich, since at idle, the clutch is not disengaging.Leaning would lead to a slower idle ? Also when I advance the throttle, from 0-45% the engine revs up smoothly, but after that it coughs up a lot of smoke and the increase in power is sluggish.

2. This one is important. How do i detect vibration on the heli, and how much is OK ? I am concerned because though I am hovering OK, i noted that on my training gear i had small dents on where the heli skids touched the CF frame. Vibration might have caused the skids to "rub" against the CF rods and dent them out. Also when on the hover, though i do not see the heli shaking a lot, i do note that some parts like the exhaust extension seems to flutter.
I know vibration is not a good thing, but then perhaps its because my engine is still rich ?

I had a video taken today. Will post it here soon.
-Gaurav

1. Let me put the disclaimer first that about 80% of my nitro experience is on the Align/OS 50 hyper engine. What I found in general is that a lot of times, I had lean the low needle from 10 to 40degrees during break-in for the engine to stop quitting frequently. 

But this may very from engine to engine.  The idea is to get a good transition from low to high, the idle is smooth, and the high conforms to the 3 to 5 second rule (can be a little rich).

Leaning the low end allows you to run the engine at lower throttle, thus helping the clutch to disengage.  Looks like the smoke indicates you are still running it too rich.  Use the backplate touch technique to lean the high needle until you see improvement.

2. This is, at least for me, very hard to quanitify   I can say whether the vibration is OK only in person.  What seems true is that quite a bit of vibration is normal/expected (again, quantifying is the problem). 

Regarding the training gear / skids issue, we need clarification whether the original skids are the ones with the dent, or the added training gears ?  In general, CF frames are sharp, and people tend to sand the edges to prevent them from cutting through stuff (wiring, your hands, etc).  Also, if something does touch those sharp edges, people tend to provide some kind of padding (it can be sleeves in the case wiring, foam padding in other cases etc).

One more thing to note is that needle settings are dependent on the fuel you use. The factory settings are usually for 30% nitro. Since you are using no nitro, your settings will be on the leaner side.

The mid range sluggishness or even quitting is common when rich. It is the toughest part of tuning a heli engine in my experience. Getting the balance between smooth idle, clean midrange and low enough engine temperature is not easy for a newbie. Commercial fuel blends help in this compared to homebrew castor-methanol. Also the more the nitro the easier it is supposed to be to tune.

On the other hand once you spool up and switch to idle up, you are never in the problematic mid range throttle position. So it is not so much of a concern.

Ok here is a video, we shot at out airshow. It isnt the best, but i guess you can see how this bird is flying.

Few things to note :
 At the beginning, as i increase throttle, note the sluggishness and loss of rpm at midstick, and from where it picks up.
How does the engine sound. Looks like its still too rich ? Does vibration look OK to you all ?

Thats about it. Look forward to your comments !

I am currently using a 1500mAh NiCad for my RX on my heli. However, I am not too happy with it. I seem to be getting a max of 4 flights before the voltage indicator starts showing caution.

I have a 6.6V A123 pack 2200maH that i want to use. However my rudder servo is Futaba 9254, the specs of which specifically say not to use over 4.8V.

Now, can I just buy this voltage regulator and use it between the Gyro and servo ?
Would it be safe to use ? How does it lower the voltage ?

Thanks !