Nitro Engine Tuning 101

[Beaver Rat]

Ok... I was originally going to tune based on backplate temp, but I will give this way a shot just looking for smoke and sound.
Thanks guys

[mark1950]

Quick question, while doing these tuning procedures are you using a straight throttle curve ( idle up ) or a linear throttle curve ( normal ), i ask this because when you go to center stick zero pitch I dont hear it over reving. Thanks mark

[HeliBenj]

They're using a governor

[Finless]

Originally Posted by HeliBenj

They're using a governor

Correct. Read a couple of posts up from this.

Bob

[stunned]

Hi Bob:

On your Trex 600N Pro Vids you mention that you will do some more videos on Setting Idle Mixtures, Thought I would ask on this tread being Engine Tuning and all?

Thanks

Mike

[Stallion]

I find these Vids very helpfull but i think i dont have the ear for it to exactly tell when it is to lean and when it is to rich. My engine has power and it runs cool but i would like to fine tune it some day. i think it is simply a matter of trial and error until i get it right!!

[Stenis bling]

Thank you Bob and Tim
I have always had a hard time to tune my engines atleast my new os91hz-ps
and these videos were great big help for me I hope have not tryed it yet
I have never get my pipe to seal well so i will give the PC-Farenheit Epoxy a shoot I order it today

Big thanks

Richard

I forgot to ask the big all time question on my engine

regarding my os91hz-ps
Should I get rid of my pump on this engine??
And if why.

[Stenis bling]

OK here is my issue
when i idle upp from start everything sounds good and good smoke to, then when i go back to idle 1 1800rpm from idle 2 2050rpm it start to go very thin and almost no smoke and if I adjust the middle screw so I dont get this I cant hardly start the engine it is very rich until I come up to idle 2, do anywone have any ideas, it has been like this for a very long time but I never cared for it, I only run it on idle2 and when finnish throttel hold. But now after this video I would gladely have a sound like the video throw all gear,

[EKAN]

When can i get this engine??

I want it now

[Finless]

EKAN, you cant get this engine yet....

Stenis, why so low a drop from idle2 to idle 1. 2050 to 1800 is a lot. I run 2050 id1, 1900 id2, and 1800 normal. Try that. Also don't forget there is an idle adjustment too.

Bob

[Stenis bling]

I have now adjust the rpm same as you Finless about the idle screw it is rock solid on mine I cant get it to turn
Ekan gave me some suggestions to skip the pump an run it direct from backplate to tank
I did this test today only hovered at home idle1 and 2 I get the middle to only four click out and high nidle half turn out, I will test pressure only from the pipe tomorrow and plug the back plate.

[Ozz58]

Can we put a link in the 101 sticky to this?

Would hate to see it get lost here.

Craig

[Finless]

KGFly manages the 101 sticky. He gets upset when I edit it and don't do things right

If you don't mind PM the guy and ask....

Bob

[sharkyh2o]

Bob and Tim,

Amazing job on the nitro tuning videos. The best tuning vid to date.

Two questions:

1) My Align 55h sounds great when flying when i load it up doing tick tocs, it's like the motor boggs down and sounds like it's going to stall. Keep in my our flying field is at 8,600 ft any suggestions?

2) Any additional items for tuning and flying at this altitude. Ex: fuel choice, rpm's, etc.

Thanks again for a great video.

[Finless]

I wish I could help on the altitude thing. I have never had to tune for more that about 1,000 above sea level. Even then there was a feel of power loss a little over being at sea level.

Bob

[sharkyh2o]

Thanks for the reply, perhaps instead of a 700n for the next build it'll be a 700e

[Raptor30_V1]

Hello Sharky,

Higher altitude means less ambient pressure and so less oxygen when compared to sea level ..

So as the air-to-fuel ratio is always what it is about - additionnally looked at over the whole carb-range, pretty sure having less air-pressure (oxygene) at your location, your needles will be leaner than settings of someone flying on sealevel .. so considering this and carb-tolerances (design and manufacturing) should make it clear, that comparing needle-turns is pretty useless. Instead the MFG default needle-settings is a good thing to get started and additionally having a solid path to follow (e.g. Tim's or Bert's approach).

Additionally keep in mind, that higher nitro-content in the fuel delivers additional oxygene during combustion (when nitro-methane *cracks* into molecules). So if e.g you fly now some 20% nitro-fuel at 8'6oo ft (wow, that's around 2'600m over sea level?) and change to 30% nitro content fuel, due to additional oxygene provided by nitro-methane, you will need to open fuel-supply too, so richening the needles ..

Temperature changes in the montains are even bigger than at sea-level, so just as a raw hint, when temperature drops, the air-density increases, so more oxygene as well and therefore theoretically means richening the needles (mainly main-needle) ..

Higher humidity somehow crowd's out the air-content and therefore theoretically means leaning the needle ..

Bogging during tic-tocs:

- either collective skills to be trained
- your mid-range needs tuning (mid-needle mainly)

As Bert Kammerer suggests in his video (smack-talk), do some consuming tic-tocs (not just 3 times) until either engine boggs or does well and then suddenly bring your bird into hoover position. If engine bogged and:

- needs only a short time to recuperate from bogging its rather rich at the mid-range ..
- needs a few seconds to recuperate from bogging its rather lean at the mid-range ..

Some people do wide loops and listen the engine sound, when throttle is around mid-range. I personally favour the tic-toc torture, as it gives me good results about the mid-range.

Tim's method for the mid-range doesn't work on my location, as the sky is not that steel-blue to see some mid-range smoke-puffs.

Best Regards,
Oliver

P.S: Funningly, when people speak about lean or rich, they always refer to the fuel-view only, meanwhile to lean can mean excess air too, e.g. untight engine or tube-leakage etc.

[dchekas]

I've watched the tuningp2basics video several times. The part where Tim says it's "a little lean", about 5:30ish into the video.

I cannot tell the difference between the sound of the engine during this segment, and the sound of it during the climb out at about 4:10. Is it just me? Or did the camera just do a poor job of picking it up?

I've listened to both these segments well over 20 times a piece. I can't notice any real change in the engine tone.

[Finless]

Unfortunately that is the truth about video cameras and build in mic's. I wish I had put on my boom mic but it is what it is.

Bob

[dchekas]

Any chance of a Nitro 201? (With boom mic!)