Basil Yousif

My Feedback: (3)

[h=1]Digital Servoless Retractable system (1pc) 54g[/h]
I have installed these in a .46 Size World Models P51. I installed them with some
HK oleo struts that have a spring. When the struts are collapsed into the wing the
electric retract doesn't reach the full travel but very close. It's only a small
amount of the last bit of travel of the electric retract. Is that okey or will it
harm the electric retract not to be all the way at the end of the strut up
location. There's no buzzing sound coming from them and they seem to work fine.
Product
http://www.hobbyking.com/hobbyking/s...dProduct=14838

scale only 4 me

My Feedback: (158)

You should be fine
These units work on a peak voltage stop not travel limit stop,,
So when it goes up and stops mechanically (binds) the motor peaks current turning itself off until you tell it to go the other way.

init4fun

Hi Basil ,

The short answer is , Yes , You are fine and will not damage your retracts if they don't retract 100% of their travel ,

The long answer is ;

All of these modern "servoless" retracts operate the same way . Namely , there is a circuit that monitors the motor's current , and when the circuit "sees" the rise in current that indicates the retract has reached it's end of travel it cuts off the current to the motor . Now , before there was such transistorized miracles , there likely would have been "limit switches" at each end of travel and until that limit switch was actuated by the retract the motor would draw power attempting to drive the arm to contact the switch . This would have been bad and resulted in drained batteries/burned motors ... But , since the circuit "sees" nothing except the rise in motor current when the end of travel is reached , it matters not where the end of travel actually is , the stopped movement and current rise/subsequent cutoff can happen anywhere within the range of motion of the gear .

I hope that made sense of it for ya

init4fun

I see scale beat me to the short answer ...

Basil Yousif

My Feedback: (3)

Good to hear that so I don't have to cut into the wing and change the wheel wells. I have to do that for a CMP P-40 Warhawk 1.40 sized plane and it isn't any fun. I used the ESM 30cc size Corsair Air retracts for that one and there's a lot of chopping, blocking and fiberglass work to be done to get the retracts installed.
I would have loved to get some electric retracts for that plane also but the ESM electrics are $300.

I think I can put together something at Hobby King for alot cheaper. These retracts in this WM P-51 were only $16 for the pair at HK - a local Hobby store was selling them for $50. Now they have the same type but metal for a few bucks more that can take a heavier plane.
I overcame the angle of the wheel well - made for the stock wire struts by getting a 5mm rod from the hardware store and bending it slightly in the middle to get the angle. It's easier to bend the rod before cutting it to size. The 5mm rods they give with the Struts is way too short anyway so it's a good idea to get the long 5mm wire rod even if you don't need an angle.