Mac190

Flying Raptor V2 with Tiger 39 that came with kit.

I have the needle open 1.5 turns. Getting plenty of "smoke" Engine idles very well here.

After flying for a minute or so - engine "bogs" down and losses power.

It seems that the engine is overheating.

All the reading I have done says that when the engine losses power during flight - and begings to "float down (even giving full stick) it is due to over heating.

How many turns do I want the needle open?

2 to 3 seems very rich.

Any ideas?

Thxs

scott36

My Feedback: (54)

sounds lean to me ,do worry about 2 or 3 turns being to much,try turning the needle out a little at a time to richen the motor up.

Furyflyer2

My Feedback: (117)

The engine is new, I would do what scott36 recommended. Smoke means nothing, you must go by how it runs and sounds.

zaremba

Hey, I'm breaking my bird in out in St. Charles, and live in Oak Park.

You're describing my symptoms exactly. And then, when you set down and let it idle for 30 seconds or so, it runs fine, but then you lose power again and can't even maintain a hover? Do you hear sizzling or popping noises when you shut the engine off? Does it have a raspy note when this starts happening?

I would be very worried about having her open only 1.5 turns!

Sounds like you're overheating. I have mine almost three turns open. I have found that when the engine sounds smoothest on the ground is not the right setting in the air. I have mine idling a bit rough (rich), with a noticeable amount of oil/fuel sputtering from the tailpipe, but it screams like a banshee when I take off. Play with the high-speed needle as well. I was messing with both adjustments for the good part of the day yesterday.

It would be nice to have a temperature gauge, since I'm just guessing, but I'd rather err on the side of being too rich than too lean. Imagine the amount of heat being generated when yer too lean...which is why most planes have a CHT and EGT gauge in the cockpit

About three turns open for both is where I'm at on 15% nitro, and it is running great. I broke the engine in on 10% castor oil, and had about 2 3/4 turns on the low-speed needle.

I had the exact same problem. Check your muffler to make sure it's still tight, and the O-ring gaskets inside the muffler are not destroyed.

Richen her up!

-Paul

Kwesdog

I had that exact same problem with mine. I would pick up to a hover then it would lose power and slowly drop and lose rotor RPM. I did alittle research on this forum about it and found that I was running a bit to lean.

I then began by just riching the mixture up by a click or 2 after each time I set down until the I got it right and now this thing will hover and fly with authority all day with no bogging down or over heating.

I forgot what the post was named that I found that helped me but I will look for it and try and link it on here for ya.


Harry

WOS

My Feedback: (62)

I have a TT 39 on my Caliber and I run between 2 1/2 and 2 3/4 breaking it in.

shawnb

I too have had problems with my raptor 30 (lots of problems). The problem you are describing sounds like it could be lean, but don't focus on that in till you rule it out. I put a header tank on mine and had a problem were the header tank would go down in fuel level faster than the main tank could supply giving a vacuum effect in the header tank. The helicopter would run great for the first 3-5 minutes and then slowly lose power intill I landed. Once it idled for a bit and the main tank refilled the header it was great for anther 3-5 minutes. I found that the fuel inlet on the new header tank was restricted slightly from the making of it. I drilled it and the output out to as big as I dare and the helicopter runs great (knock on wood) ever since.

planelazy

I have a Rappy V2 with the 39 and with Cool Power 30% am running the main at 3/12 turn's out and the thing screams.It runs great.I know it is much further out than normal but it seems to like this setting,at least on 30%. Tim.

Galifrey

If I can offer some advice...

First thing I have noticed is that needle positions are not important, as it depends on your altitude, humidity etc etc...

Dont try to copy someone elses needle positions as unless you are using same engine, heli, pitch curve, glowplug, at the same altitude on the same day with the same humidity and barometric pressure with identical fuel pressures and same muffler you are wasting your time...

Start at the manufacurers settings. They are a good basis for a start point...

The TT39 carb works like this... It has a main jet that is fully open at full throttle, this provides the fuel air mix solely from the needle valve position only at full throttle.

The Idle needle is a smaller tapered needle that moves in and out of the main jet regulating the flow according to the opening position of the throttle...

At settings below full throttle ie hover, then the mixture is dictated by the pressure from the main needle and the position of the idle needle in the main jet...

If you can get hold of a set of headloders then you can get your mixture there or thereabouts to start with and then fine tune in flight...

I start (there are other ways) by getting the mixture correct at full throttle as this is fixed by the main needle position I do this roughly by using full negative pitch at full throttle (it gives a rough start point)...

Then I tweak the idle needle to give me a decent hover which gives a similar level of smoke with no four stroking (rich) and no crackling (lean)....

After you have run this for a tankful and no ill effects land your heli and check the crankcase backplate...

It shouldnt be any hotter than that which allows you to hold your finger on it for 2 seconds before having to remove it due to onset of pain...

If you can hold it there indefinately then you may be able to go leaner....

Check the full power climbouts to see that it doesnt bog due to leaning or splutter due to richening, if it does then you can adjust the main needle accordingly, but if at this point you lean the main needle you will probably have to richen the idle slightly (or vice versa)...

I hope this helps you get your TT39 tweaked as its a great engine..

PS if your engine leans as the tank empties you may wish to uniflow your tank to maintain a more consistent fuel pressure. If you do uniflow you will probably find you have to richen the main as it will lower the starting pressure of the fuel.

FLYBOY

My Feedback: (11)

You may also want to look at heliproz at the temp sensor for the engine. this will help you set the needle to get the right temp. If you are new enough not to know how far the needle should be open or the right sound, the temp sensor can help you keep from burning the engine up right away. They are very cheap.

It sounds like you are way lean though.

AdamB

My Feedback: (9)

Like said above, every needle setting is different.

My OS manual said to open main needle about 1.5 turns for break in. I had to open it 3 full turns to get it to run right. I'm guessing I'm at still 2.5 turns open for proper run in my area.

It definitely sounds like you are lean. Just give it a couple clicks counter clockwise until she runs better.

Eventually, you'll have to lean your low needle (probably), at least I always do.

eddie13231

My Feedback: (3)

All of you say that your heli screams...on a raptor 30 this is not good. You CAN do this, but not for long time. If the headspeed is over 1800, you will break stuff. Buy a min-air pitch gauge and get your hover in normal to like 1650 and idle-up to 1750-75. Please make the investment.

bigbigjoe

My Feedback: (2)

What fuel are you using? If it isn't heli fuel it does not have enough oil in it and this is causing the overheating problem.

Spaceman Spiff

My Feedback: (1)

Uniflow?

randy41

Spaceman Spiff : click on the below link and read until
your eyes fall out . LOL


RC Uniflow system

Spaceman Spiff

My Feedback: (1)

Pretty clever, i might have to give that a try.

Thanks Randy

bigbigjoe

My Feedback: (2)

What fuel are you using? Is it heli fuel?

Spaceman Spiff

My Feedback: (1)

The guy who wrote the uniflow article should consider hiring an engineer for the day. That article could use a little help.

AdamB

My Feedback: (9)

The uniflow system works though... I may have problems, but it is never with the AFR of my engine.