Retract servos help
 

I am not getting much in the other forums, so thought I would try here. I have *gasp* and arf Hanger 9 P-47 150 with the retracts. The retracts use JRPS791 servos. Only issue is they are only 4.8 volt servos, and im running a 6.6v Life pack. So looking for alternates that run at 6v for this. HS-75BB, any good? Any others? I would prefer not to have to add a second voltage regulator as I have to use one for the MPI Servo reversing Y for the flaps. They JR are also $60 a pop, where the Hitecs are $28.

I had some 4.8v JR retract servos also. I added a couple of diodes in the servo leads to drop the voltage and they worked fine.

I would like to avoid modifications if I can, but I do have a voltage regulator in use for the Y reversing harness for the flaps. I could probably make up a harness to power the 4 servos through that while connecting the signal to the RX. I make my own leads, so not a big issue, but would like to avoid it if possible.

ACDII

I was going to suggest exactly that (piggy backing off the flaps voltage regulator)...I was about to make a sketch even when I saw that you had wrote this latest post. Just be sure everything (signal and power) has a common ground....

Either this or the diodes will get the job done - and will not cost you much in the process..

Then again---I just re-read everything and realized, you don't have servos yet. So your not tied down one way or the other. There are certainly other servo's out there... I won't endorse any particular but I use quite a few of the "No Name" brands. However, I don't have any retract experience.

It appears most of them are out of stock, including the recommended JR's. I am using MPI servos for this bird, and have used Hobby People servos in other planes and never had a problem. the only thing the JR's have over all the others is the high torque rating, which is probably why they are $60 each where the others are $28 each. The other downside is the retracts are designed specifically for the JR servo, anything else I would have to open up the area the servo fits in a little, by about .03". I looked at TH, but they are all on back order, but do see the JR's in stock at a few online shops, so I may just bite the bullet and pay the extra $60something for the Jr's to get it done.

The Hitec HS75's are great servos. Will last years. Will work with the newer higher voltage battery systems...etc... I have several.. I've used one in every retract application I've done. You can't go wrong.

I'm not familiar with the JR 791 servos you're replacing.. but do be aware(you probably are already).. the HS75's are full 180degree rotation.

I'm curious about the regulator you're running for an MPI servo reversing Y for your flaps. I have an Expert brand(Horizon Hobbies) reversing-Y in 2 of my planes, using LiFe batteries, and have zero problem.

Good luck with it.

Thanks for the input, I am leaning towards those servos even if I have to grind a little off the gear to fit them in. 180* should be fine, as I am pretty sure the JR ones are the same.

The Y is an MPI used for older Airtronics servos, which were 4.8V only at that time.I picked it up at a swap meet in Toledo and since I had to go through and replace all the connectors to make it work, he just gave it to me.