dirt kicker

hey guys ! , so today i got my tiger 40 trainer running up , the engine im using is a thunder tiger thunder pro .46 , it seems that when its idling very low it vibrates one hell of alot ,which cant be very good for the my planes components ....

any ideas on how to fix ??

MinnFlyer

My Feedback: (4)

Check the balance of your prop

jetmech05

I agree....balance of the prop and make sure that it is on the shaft straight and tight.......make sure that the hole in the prop is centered......if the hole in the prop needed to be stepped up bigger did you drill it or ream it by hand...if you drilled, the hole is probably off......
Make sure the engine mount bolts are tight and that the mounting feet are all the way down on the mount....if you can't find anything get a new prop

Scar

My Feedback: (3)

Yah, don't let it idle so low!

Seriously, the prop balance is critical for high RPM, but if you try to idle under 1100 RPM or so, that single cylinder engine is going to have its own dynamics. Rev it up to 1500 or higher, you're probably seeing it smooth out. Doesn't need to idle slower.

I might even be optimistic about those numbers, seems like my .25 wanted to idle over 1300, so I just guesstimated that 1100 number. Maybe should be higher. If there's a low speed at which it's smooth, and the prop isn't pulling the plane, you're probably okay.

Of course, if you rev it up and it's shaking the plane sideways, then your prop is actually unbalanced or off center.

Just my 2¢ worth,
Dave Olson

JohnBuckner

My Feedback: (1)

Is there a spinner involved and if so what type and what kind of adapter?

downunder

Quite often a vibration at low speed is caused by a harmonic resonance between the natural vibration of the engine and the airframe (usually the wings). A slight change in revs will cure that.

jaka

Hi!
What kind of engine mount do you have?
And Please! Do not use a cheap plastic spinner! Use an aluminum spinner nut!
Aim for 2000-2500 rpm at idle! And use a 11x6 or 12x4 APC or RAM prop!

speedracerntrixie

My Feedback: (29)

I think most of the suggestions here are good ones. Not too sure I buy into the too low of an idle as my engines do not vibrate at a very low ( below 1400 ) RPMs. I see that you are a gas car guy. You wouldn't by chance be using your car fuel or plugswould you? Usually a gas car gets set up pretty lean on the idle mixture, this is done for quick accelleration. You may just be too lean on the bottom end and this could create pre-ignition which would cause vibration. Running car fuel with it's lower oil content can do the same and if that's not enough LOL. If you are using your car plugs,they could be too hot of a heat range and that can contribute to pre-ignition too.

dirt kicker

hye guys sorry , been a busy 2 days !!! haha

yeah i am more orientated around gas / nitro cars this airplane jazz is still very new to me , !! thanks for all the help and input guys ! , to answer most of your questions the mixture needle is scrwed out 2.5 turns , i am using an aluminum spinner nut , and yes the plane as smooth as my car at higher revs ,

but if i increase my revs , my plane will run away from me when i just want it to idle ... not so ??

dirt kicker

okay guys , so i just started her up now , vibration seems better , but now i have another issue !!!! ,

when it idles , it idles fine , if i bang the throttle up it dies out , if i increment slowly up , it almost dies and then gets going , with alot of smoke , !! and spitting nitro all over my plane , then when i bring it down to idle again , it dies out !!!!!

this cant happen during flight !!! please help , could it be mixture to rich or lean ? bare in mind the motor is 8 years old and only now has been started

hogflyer

Sounds like your mixture is too rich.

Start with setting your high-end mixture first - lean it until the RPM peaks, then back it off about 4 clicks rich, or about a 400 RPM drop.

Next start leaning out the idle mixture about 1/16 of a turn at a time and see what it does. You'll find that when you make a change to one mixture setting it will affect the other, and on some engines it just takes a bit of tinkering with them before you have everything dialed in.

Hogflyer

jaka

Hi!
As has been said!
Sounds like a too rich idle setting! Remember that you always set the needles by ear! Not in how many turns the needle has!
In an ordinary sport engine that you have an OS 8 or Enya 3 glow plug is a good choice! There are other plugs too that are as good like the Nova Rossi 4 or 5 or Rossi 3 or 4, but the Enya 3 and OS 8 are the old -stand-by:s that are easy to find in most hobby shops!

Do use 5%-10% nitro! That's what all engines likes! 15% is overkill and more nitro and your engine will probably experience bad running behavoir (wrong ignition point) due to too much nitro!

dirt kicker

but also my engine only has one needle !! not 2 and im using O.S 8 , thanx !!

jaka

Hi!
No!
All TT .40-46 PRO SE engines have a two needle carb! Like nearly all other ball bearinge engines. pic shows the Kyosho GX.40 and SK .40.
Look on the left side of the carb (from the front). In the center of the throttle arm there is a small screw! That's the idle needle!

dirt kicker

oh okay cool !! , thanx ive just checked ! , my screw is set horizontaly not verticly and the space between the screw and the engine block is about 20mm , so will have to unscrew it with plyers ,

so leme get this strait : does the plane idle better if the screw is turned more in or out ?

JohnBuckner

My Feedback: (1)

DK you are looking at the wrong screw. Look at Jakas picture agine the one on the left, now find the throttle arm (that is where you hook up the pushrod from the throttle servo). Inside this throttle arm where it pivots is a hole and you can see inside this hole a tiny screw with a screwdriver slot. This is the mid range needle valve on a TT Pro and on the engines in Jaka's photos.

John

r ward

if you have a spinner on the prop. make sure the cutout for the prop is not touching the prop anywhere. if it is, it may be pushing the spinner off center because the plastic spinner plate is being warped by the contact, that will cause an imbalance.