YAK 85, rotation speed for barrel (rolling)

YAK 85, rotation speed for barrel (rolling) (Full Version)

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bart-rennes -> YAK 85, rotation speed for barrel (rolling) (5/3/2007 4:24:12 PM)
I have my yak 85" with a ZDZ50NG and since the beginning i found that speed of rotation for rolling (barrel) is very very low: around 2.5 seconds to do a rotation !! My ailerons settings are bigger than the manual, i change all servos (from TowerPro 995 to Blue dird) and result is the same. Any idea ? is it normal ? Thanks jean-claude

Aero104 -> RE: YAK 85, rotation speed for barrel (rolling) (5/3/2007 8:21:29 PM)
I am not sure which Blue Bird Digital servos you are using, but the biggest I was able to find online was about 140 oz/in of torque. Based on some internet servo calculators (http://www.csd.net/~cgadd/eflight/calcs_servo.htm) you would need a MINIMUM of 300 oz/in for this size of aerobatic plane. I think the instruction manual for the 86" yak states "JR8611a or equivalent." (8611a running on 6v, gives you 320oz/in). The same would most likely be true for the 85"yak. You will be risking control surface flutter and crash with anything smaller. Most people here in US are using JR8611a (320oz/in) or Hitec HS-5955TG (333oz/in.). I hope this was helpful. Aero104

bart-rennes -> RE: YAK 85, rotation speed for barrel (rolling) (5/3/2007 8:37:20 PM)
Thank you Aero104 for your answer, my current servos are BLUE BIRD BMS 610 MG+HS give for 9.7kg (around 342oz) and before it was TowerPro MG995: given for 12kg (around 428oz), same result !! jean-claude

Icaro2004 -> RE: YAK 85, rotation speed for barrel (rolling) (5/3/2007 9:21:32 PM)
Jean-Claude If you use a programmable radio, Have you checked servo speeed?

Rezagh -> RE: YAK 85, rotation speed for barrel (rolling) (5/3/2007 9:28:59 PM)
Jean-Claude, That speed is extremely slow. I have to back down my throws because the plane rolls so fast to keep up at full deflection. Please check your servos and battery system. Let me know about your findings. Reza

Aero104 -> RE: YAK 85, rotation speed for barrel (rolling) (5/3/2007 10:24:12 PM)
I think there is a conversion problem here... I found this link for the blue bird 610 mg and it lists 9.7kg/cm or 132oz/in. http://www.clodparts.com/products/servos/9.html ---> NOTE the torque data is measured differently for US and metric. Force (kg or oz) x Arm (cm or in) = Moment (torque: kg/cm or oz/in) Therefore a smaller distance OR weight will cause overall torque to be less. You can't just covert the 9.7kg to oz, you have to account for the distance difference (10cm approx 1/4 in) So, long story short... servos are way too small. Does that make sense? I just learned something here myself... I think ?? Best of luck, aero104

Aussie_Knife_Edge -> RE: YAK 85, rotation speed for barrel (rolling) (5/3/2007 10:33:54 PM)
My Hitec 5955TG's are rated at 24Kg and have 333 oz in of torque at 6V. Your servos are less than half at 9.6Kg so your torque would be less than 150 oz in. Try some decent servos and I think you'll be amazed at the difference. Cheers Jason.

bart-rennes -> RE: YAK 85, rotation speed for barrel (rolling) (5/4/2007 8:36:53 AM)
Ok, thanks to all, i will try another servos and let you know the result. jean-claude

bart-rennes -> RE: YAK 85, rotation speed for barrel (rolling) (5/4/2007 10:14:36 AM)
I've just check availability in France for JR8611A servo, we can find only the JR DS8711. So which is the best: HS5955TG or JR DS8711 (JR price is lower) ? Thanks jean-claude

Rezagh -> RE: YAK 85, rotation speed for barrel (rolling) (5/4/2007 3:18:31 PM)
Jean-Claude, The 8711a are stronger. I love mine. I think you should go for it. Reza

bart-rennes -> RE: YAK 85, rotation speed for barrel (rolling) (5/9/2007 10:36:36 AM)
So more information about my problem. I use an automatic battery switch from Robbe for security purpose (http://at.robbe-online.net/rims_at.storefront/464192e5003567b9271b3e0dc1460679/UserTemplate/1/?ISID=464192e5003567b9271b3e0dc1460679). I discovered that the switch give 3.5A continuous and 5A at peak, do you think it is enough for the yak 85 ? For testing i remove the switch and tried to move the aileron with my hand: result very hard, i set the switch and result: more easy to move... Thanks jean-claude

Rezagh -> RE: YAK 85, rotation speed for barrel (rolling) (5/9/2007 3:27:51 PM)
Jean-Claude, I would at least use a switch with over 6 amp continuous rating. I guess your regulator/switch rating is LOW for this plane! I think you have to get a good power system + good servos and regulator or it will be just a matter of time before something giving up! The least is you will not be enjoying the plane because your set up is not right. Thank you, Reza

bart-rennes -> RE: YAK 85, rotation speed for barrel (rolling) (5/9/2007 3:41:02 PM)
Thanks reza, i will change all of this. The servos Hitec 5955TG has been ordered, which battery regulator/switch do you think i should use at good price ? (smart-fly standard regulator ?) Jean-claude

Rezagh -> RE: YAK 85, rotation speed for barrel (rolling) (5/9/2007 3:47:31 PM)
I'm not sure what kind of smart-fly regulator you need. I think you need to research that yourself from their website. Quique and I have been using one Duralite heavy-duty failsafe switch with 6 volt regulator. Here's the part number #65060-HD and here's the link http://www.duraliteflightsystems.com/accessories4.html#Heavy it goes for $59.95 (switch and regulator). I have been using the same set up in my 102" Yak as well. Never had a single problem. Good Luck, Reza

bart-rennes -> RE: YAK 85, rotation speed for barrel (rolling) (5/18/2007 3:28:04 PM)
I've just tested the hitec 5955TG on ailerons and result is a better but not awesome. Tested with my Robbe battery switch and without it: no difference. I use 2xNICD 1500mah, do you think it can be the receiver (don't have power expander or similar) ? i use the Futaba R147F receiver... Thanks for your help jean-claude

Aussie_Knife_Edge -> RE: YAK 85, rotation speed for barrel (rolling) (5/18/2007 9:55:37 PM)
G'day Jean-Claude, I'm using 5955TG's all (round except throttle) on my 73" Yak and have awesome roll rate... I don't use a regulator at all. I'm using a 2000mAh NiMh Rx pack and a heavy duty switch. That's all.. Are you using the heavy duty Hitec servo extensions? Which control horns are you using on the servos? Cheers Jason.

bart-rennes -> RE: YAK 85, rotation speed for barrel (rolling) (5/19/2007 7:58:32 AM)
Yes i use the heavy duty hitec servo ext. The only thing i can see is that my receiver don't give enough power to servos... But it is impossible to get datasheet from Futaba... Any other idea on my problem ?

Aussie_Knife_Edge -> RE: YAK 85, rotation speed for barrel (rolling) (5/19/2007 10:35:43 AM)
The receiver should be able to supply enough power. Are you using 4 or 5 cells for the Rx pack? I use 5 on my Multiplex Rx. The 5955TG should have enough power to snap the ailerons off your Yak... They are rated at 24kg! Are you using the recommended control throws? It's just a process of elimination.. Cheers Jason.

bart-rennes -> RE: YAK 85, rotation speed for barrel (rolling) (5/19/2007 10:48:43 AM)
Jason, i use 2 NICD of 5 elements (1500mah each), the controls throws are the DU-BRO include with the 85" kit. Which measure do you have for the ailerons (up and down at high rate) Note: the 5955TG are rated for 24Kg but the real measure is only 13kg !!! (measure done by independant people)

Aussie_Knife_Edge -> RE: YAK 85, rotation speed for barrel (rolling) (5/19/2007 10:59:08 AM)
This is what the manual says... Low Rate (Expo 70%) High Rate (expo 75%) 80mm 100mm 80mm 100mm I'd at least set it up as above. Cheers Jason

bart-rennes -> RE: YAK 85, rotation speed for barrel (rolling) (5/19/2007 11:38:54 AM)
Wow!!! 100mm, manual say 76mm at high rates... We are talking of the YAK 85" (2.15m)

Aussie_Knife_Edge -> RE: YAK 85, rotation speed for barrel (rolling) (5/19/2007 11:45:19 AM)
Oopps! Sorry Mate thought it was for the 86".

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