CARF Ultra Lightning main doors opening in flight.....what PITA
11-14-2016, 09:35 PM
#1
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Join Date: Jun 2006
Location: Gold Coast, Queensland, AUSTRALIA
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CARF Ultra Lightning main doors opening in flight.....what PITA
Guys,
I have the Electron 50 evo retracts fitted to my UL and use the electric brakes and door options too. Everything about the setup is fantastic ....but the doors will not stay closed during high speed flight. Allow me to quickly jump in, before you ask - yes the doors are setup for the servo power to stay on all the time. The servo's are 4.3kg JR wing servo's. I have bent the leading edges of the doors towards the wing in order to try and prevent airflow from 'lifting' and opening the doors - but still no luck.
What to do? No, I don't want to go to air (it will be the only air system on board) or worm drive actuators (they are too big and won't fit).
I have long plastic servo arms fitted - it has been suggested that I change these to metal arms - will that realy help?
Thanks for your suggestions.
Jan
I have the Electron 50 evo retracts fitted to my UL and use the electric brakes and door options too. Everything about the setup is fantastic ....but the doors will not stay closed during high speed flight. Allow me to quickly jump in, before you ask - yes the doors are setup for the servo power to stay on all the time. The servo's are 4.3kg JR wing servo's. I have bent the leading edges of the doors towards the wing in order to try and prevent airflow from 'lifting' and opening the doors - but still no luck.
What to do? No, I don't want to go to air (it will be the only air system on board) or worm drive actuators (they are too big and won't fit).
I have long plastic servo arms fitted - it has been suggested that I change these to metal arms - will that realy help?
Thanks for your suggestions.
Jan
11-14-2016, 09:50 PM
#2
Jan,
people often underestimate the servo torque it needs to keep those big doors shut at higher speeds. This has nothing to do with the fact that you are using plastic arms.
I also had the same trouble with my Carf Tutor, the doors are about the same size as your Lighting. I started with a set of JR HV micro servos with about 3kg of torque, but these were too weak. Since there's not a whole lot of room in the Tutor wings, I installed the strongest medium size servos I could find. These are the MKS 747 HV servos with about 200oz of torque at 7.4 volts. These worked fine for me.
Thomas
people often underestimate the servo torque it needs to keep those big doors shut at higher speeds. This has nothing to do with the fact that you are using plastic arms.
I also had the same trouble with my Carf Tutor, the doors are about the same size as your Lighting. I started with a set of JR HV micro servos with about 3kg of torque, but these were too weak. Since there's not a whole lot of room in the Tutor wings, I installed the strongest medium size servos I could find. These are the MKS 747 HV servos with about 200oz of torque at 7.4 volts. These worked fine for me.
Thomas
Last edited by bluelevel; 11-24-2016 at 09:01 PM.
11-15-2016, 01:19 AM
#3
Set the linkage so it travels to a 'locked' linkage inline with the servo centre/spline. then there is no servo load when the doors are open. You also need the linkage as far out as possible from the door hinge for leverage, Air cylinders are way over the power of a mini servo.
11-16-2016, 12:27 AM
#4
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Join Date: Jun 2006
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Dave,
Yes I think the in-line 'locked' setup is a good suggestion. Will see if I can get it done. Otherwise I will have to go the same way as Thomas did - definitely don't want to go air only for the doors.
Cheers,
Jan
Yes I think the in-line 'locked' setup is a good suggestion. Will see if I can get it done. Otherwise I will have to go the same way as Thomas did - definitely don't want to go air only for the doors.
Cheers,
Jan
