111NELLY

I HAVE JUST PUT A THREE BLADED HEAD ON MY HIROBO 30 LAMA.NOT FLEW IT YET BUT PEOPLE KEEP TELLING ME I WILL NEED 2 GYROS FOR THE HEAD.WHATS THE PERPOSE.AND DO I.HELLY NELLY.

slider46

If it was me, I would try getting it light on the skids and see if the 3 blade head has change the way the heli feels. If it feels good and you can handle the change fly it, If not then adding gyros might be the answer......

glloq

Hi Nelly,
I installed... 3 gyros on my Lama 30, 3 rotor head. More details here:
http://www.runryder.com/helicopter/t207244p15/
and
here:
http://www.runryder.com/helicopter/g...?script=Lama_E
With one gyro on the elevator and one gyro on the aileron (and of course one on the tail) I forget I have no more flybar... and it seems to fly better. Check also the video.
Regards
Pierre

111NELLY

compliments on the paint job very nice.can i still fly it with out gyros. i noticed you.ve change to electric how long do you get on the batterys. and is there any difference in performance

glloq

Hello Nelly,
sorry for the delay, I did not see your post. Sure you can fly without gyro.... but it will be a little bit tough. Just try and don't go to high ;-)
With the battery, I was able to fly 18 minutes with 2 x 6s2p 4000mah ijn parrallel and 2 blades.
Now with the 3 rotor blades and the 2 gyros, I can fly around 13 minutes. But enough for 2 flies !
About the performance... electric rules. Did you see the video ? And thank for the paint job comment ;-)

111NELLY

thanks for the reply i flown it and did not like it going to change back to two rotor head. i am going to convert to lipo power.then the wife will let me use the kitchen table.no oil or crap anywere. many regards helinelly happy flyin....also new paint job. snow patrolred

Christopher J

What didn't you like about it? Did you have the swash follower phased correctly. If they are are not right the head will not react right and hinder any possible enjoyment.

111NELLY

hi christopher thanks for the reply. every thing was going great at the hover,then i tryed to do a curcuit. has i turned left coming back on myself the nose went skywards and tiped to the right, i s..t myself if you no what i mean. i then landed safely. some of my flyin buddies said it may need wieght at the front i will give it ago this week end,i will let you no the outcome.many regards helinelly neil.....

Bxcar32

How fast were you flying when the nose pitched up on you? If you were flying fast, you probably had a aerodynamic phenomena called retreating blade stall happening. Combined with gyroscopic procession (which states in a rotating disc, inputs to the rotor disc take effect 90° later in the direction of travel) you will see the nose pitch up on you when you fly to fast.

Aerodynamic classes for retreating blade stall are pretty in depth, so I’ll try to keep it simple.
In a hover, the lift generated by each blade through out their entire rotation is equal. In forward flight, the retreating blade in a rotating disc has to increase pitch relative to the advancing blade to compensate for the loss of available lifting surface in the retreating blade. The faster you fly, the less efficient your retreating blade becomes and thus the less lift it can produce. When you have reached a speed where the retreating blade can not produce enough lift to compensate for the lift generated by the advancing blade, the retreating blade will “stall�. This retreating blade stalls at roughly 90° from the centerline of the helicopter. Because of gyroscopic procession, this retreating blade that has stalled on the right side of the helicopter, the stall will take effect at the aft section of the rotor disc. This has the appearance of the helicopter pitching up.

That should explain why your helicopter pitched up on you. It also might help if you check out the following links about helicopter aerodynamics. You might find them useful as you continue to fly your Helicopter.

One important note about these links is that they are written for rotor systems with a counter clockwise rotation. This makes some of the rotational information different as your AS 350 Ecureuil has a clockwise rotation in its rotor system. It is also advisable to read through the transverse flow effect as well since it acts on your rotor system similar to retreating blade stall. Some of the documentation about retreating blade stall combines these two effects on your rotor system as only retreating blade stall.

Good luck and have fun.

http://www.copters.com/aero/translational.html
http://www.copters.com/aero/torque.html
http://www.copters.com/aero/retreating.html
http://www.copters.com/aero/gyro.html
http://www.copters.com/aero/lift_dissymetry.html
http://www.copters.com/aero/transverse.html
http://en.wikipedia.org/wiki/Retreating_blade_stall

Bxcar32

Oops,

I was looking at the MSComposit site and forgot you were flying a Lama. Your rotor disc still has the clockwise rotation so the information will still work for you.

KC9ICK

christopher j and hooker 50 has it nailed! phasing is a must on any multibladed head and really a gyro is not really neccessary, it's all in the phase and or you might think like timing . ken

Christopher J

As hooker50 noted a multi will pitch up, especially in fast foward flight. With multis you need to fly them a little less rigouresly then you would a two blade flybarred head.

I've been flying a friends multi bladed EC 135 this year but it has a Helitronix mixer and two CSM 180 gyros on the cyclic. I never got it going at a "good clip" in speed but have had put it through some paces. The gyros definately made it feel good and not get pitchy.

111NELLY

hi my fellow flyers.thanks for the reply. and tecnic.christophor j/kc9ick/hooker 50. with out you guys i would still be grounded,but now i have nailed it.so thanks again.i will send you all some photos next time i fly it.thats if i get the chance.british weather this time of year is like nasa,s wind tunnel.see you all soon. happy flying..

KC9ICK

111nelly> oh thats too funny! nasa's wind tunnel HAHAHA! had a breif flashback on that! ken

111NELLY

well its true. i wish i and my family lived in USA. claer blue skys not much wind and brill flying. but today in england raining all day.and very windy. you don,t no how lucky you guys are. regards helinelly...