gnirwin

My Feedback: (25)

I have a problem with a retract servo and I don't know what caused it. I purchased a new Hitec retract servo (don't know model number but it's the only one Hitec makes) that i'm using with a set of Robart retracts. When I assembled everything the retracts would not close, they would open but not retract. I am using heavy 3" tires. I switched the battery to 6 volt and they worked fine for about 10 cycles and now they don't work at all. It appears the servo is no lomger working and I wonder if it was the weight of the tires or the 6 volts that did the servo in or was the Servo defective from the beginning. Anyone have any similar experiences. I am under the impression that all new electronics work with either 6 or 4.8 volts.

Scar

My Feedback: (3)

The servo should work fine with either voltage. HT will more than likely fix it for you, no questions asked.

I'm guessing your first operational check should have been for binding. Since the retracts didn't want to retract with 4.8V, and did with 6V, it appears the extra voltage & power overcame some drag or binding. You will need to eliminate any drag or binding before you continue. Each retract should work with a light pull or push on the linkage (with servo disconnected.) If you need more than a gentle push on the linkage to get the wheel up, fix the obstruction.

You will want to make this all happen before you install another servo. I suggest making sure the new servo retracts the wheels very quickly with a partially discharged 4.8V battery, before you continue.

Good luck
Dave Olson

gnirwin

My Feedback: (25)

No, there was no binding. everything was free and easy with good clearances. When I put smaller wheels on the retracts work fine. larger they extend down but not up. unless more volts

Edwin

My Feedback: (2)

Weight can be an issue. I just went thru a hs75 (hitec retract servo) on my H9 P-40. Seemed to strain to get the gear up. I checked the linkage several times looking for binding and never found it. I concluded the gear was just too heavy for the 92oz servo to handle, cause it eventually stripped the gears. I replaced it with a JR791 retract servo. Much much better. This servo is 290oz and easily litfted the gear. Problem solved and I'm a happy camper now. Since this was my first mechanical retract setup I relied on what others said. Got burned. All of my retract experience is with air.
Edwin

gnirwin

My Feedback: (25)

thanks, i'm sure now I have the same problem. This is my first mechanical retract as well. I will switch to the stronger servo. What kind of price on these?

mustangman177

O.K. Here's how I solved the problem. When I went to retract the wheels after take off, I would roll the airplane on the back and then hit the retract switch and let "Gravity Assist" help bring in the wheels. Putting them back down, keep right side up and let "Gravity" work its magic.

Honestly, though I did not have trouble getting my mechanical retracts to work, but it would be fun to do, and put less strain on the batteries when retracting the gear.

Not to say it wouldn't work in your case if you can fly her on her back long enough to get the wheels up.

Cary

gnirwin

My Feedback: (25)

Actually it wouldn't work for me now because as I stated the servo does not work at all now. I still would like to know what could have been the reason for it's demise.

old bird

Ditto what Edwin said. I went through the same problems with the Hangar 9 Corsair. Heavier wheels and the Robart strut covers equalled a burnt our HT retract servo.

Best regards from old bird.

Bax

My Feedback: (11)

If you have larger wheels and the servo starts to have difficulty retracting the gear, you can go to one servo per gear or add springs to help counter the weight of the wheels. Add a spring to the actuating arm of the gear unit to help in retraction. Ideally, the spring should just balance the weight of the gear so that virtually no effort is needed to retract the gear.

Counter-balancing the weight of the wheel and gear leg becomes especially necessary in scale models where the scale strut and wheel wind up considerably heavier than just the gear wire and a sport wheel.

MinnFlyer

My Feedback: (4)

Just to give you all a "Heads Up", I am currently working with a manufacturing firm to start making the retracts I designed a few years ago. They are the only ones I ever use. Their biggest feature (Aside from being made from aluminum instead of plastic) is that they work almost effortlessly. No more "Rolling inverted to get them up". In fact, they work so easily, that a single STANDARD servo can easily opperate BOTH wheels!

Here's a video showing how easy they work:

http://204.96.183.34/RCU/grafx/Retract.wmv

Edwin

My Feedback: (2)

Minnflyer,
That video will be a good advertisment for ya.
Edwin

MinnFlyer

My Feedback: (4)

Yea, they're in the prototype stage right now, and if all goes well they'll be in production in about a month. The Manufacturer is hoping to keep them in the $50/set range. The only bad thing is there is not a Nose Wheel version (Mainly because I never use a nose wheel with retracts)

mirwin

My Feedback: (1)

Well, I'm impressed. Hurry up!

And please keep us posted.

And best of luck.


Mike