Century Falcon 46 vibration

[SpenceB]

Hello!
I have a Century Falcon with an OS 46 motor, In a hover, the fuel sloshes quite a bit, have balanced the MR chord wise and then span wise on a high point, Balanced the T/R as well. I have tried different Head speed. Short of removing the motor and checking it out, I am searching for a soultion.

[hawkman]

I know this one!!

I had a Century Hawk and this had the same problem.....its actually down to engine tuning.....the engine might be 'pre detonating' which will definatley cause a bad vibe.

The solution is to re tune....use the low end needle....this is the tiny screw inside the throttle arm/barrel.....you can then use the main needle too...the idle needle affects running from idle up to the hover point....the main needle has a strong influence of course....but get the idle needle in the sweet spot and the sloshing will stop.

Do not try using a header tank or any device....it wont work....the air bubbles still get in and will get into the carb....which causes more problems...notably the tail will swing about....where you then blame the gyro!

Take your time with the tuning....always make sure there is some oil on the skid below the exhaust...this means the engine is getting lubrication.

The problem isnt helped by the fuel tank....its held ridgid between the main frames right? I tried isolating mine by mounting it lengthways and had to make a base to do this....but it didnt help at all.

Its tuning for sure.

Rob

[hawkman]

If you go to the photos section on this site...type in Hawkman....you should find a photo of my old Hawk...you might just see how I mounted the tank...it didnt help any.

I liked the Hawk, great little heli....I got a Century Predator now...the gas version....you will see that in the photos.....flys well.....but scary though.

Rob

[SpenceB]

Thanks Hawkman!~ I have lot's of Helicopter maintenance experience The real ones but some things are just different! I will try your suggestions, will let you know, Thanks a bunch!

[hawkman]

No probs....the condition is a common one....with the Century Hawk/Falcon series...the fuel tank looks like a washing machine...I found that adjusting the pitch and throttle curves would help....but at certain vibes the foaming would come back..very frustrating. Most other heli models have some degree of damping.

I work on real helis too, as a fitter; on Sikorsky 61's.

Rob

[SpenceB]

Hi Rob,
Thanks for the help! It will be a while before I can fine tune the Falcon. was flying for my brother and dumb thumbed it! I need to fly at more altitude! Like a mile!! About 100 strikes high! I am just getting back into RC helicopters, used to not be a recepient of Gravity so often!! I am determined, might get a Trex 600 N.

Spence

[hawkman]

The Nitro Rex is meant to be pretty darn good....if the spare parts prices are as sensible,as for the electric version, then Align have a bright future.

I just cant get my head around the cost of spares....blades I can understand especially if they are carbon....and bling I can understand to be quite pricey.

Rob

[SpenceB]

Hi Rob,
Thanks for the reply! Raptor blades will work on the Trex 600N I understand, around $25.00 for the wood ones, that is all I deserve right now!! Ha! I believe I favor the belt drive T/R !
I have ordered 6mm carbon fiber tube and will try to make my own T/R drive using the ends off the old one. I am waiting for parts for the Falcon. Had a feathering shaft and main shaft and a set of wood blades. So I have the rotor head finished, balance chord wise with a high point, install the blades and balance span wise. I have found that even though the blades are close in balance, it pays to check the spanwise CG and compare the weight. I like them as close as I can get them! Balance as an assembly makes a Smooooth rotor! Need to figure how to use a Chadwick! That would be something huh! I'll keep you posted Rob when I get the Falcon flying again, anxious to play with the low end mixture now!
Have a Great week!

Spence