35 Sbach Scratchbuild

[SnowDog]

For my next installment, here's a modification I made to the servo location. The plans call for the servos to be placed in the root sheeted area between the second and third ribs. I initially placed them in that location, but had concerns. Then someone brought up my very concerns in my other build thread. Once that happened, I had to move them. I was really concerned with this being a 3D plane, there would be a lot of stress on the servos in the original location.

So, here is the mod I made. It would've been nice to have done this before the wing was covered, but I feel it was worth it. I cut the covering from the center most rib bay and built a servo tray that is more centrally located in the wing to distribute the pressure on the ailerons more evenly. Once finished, I simply recovered the rib bay, and installed the servo

Andy, I think this was a good choice...sounds like the initial location was way too far out on the wing. Looks like you'v got it in a better location and very strong. Nicely done!

Also, the rest of the build pics are awesome. Can't wait to see the flight videos!

 

[abaser]

Yeah, if you look at the left wing, near the edge if the sheeting, you can see the original location. The horn was to mount about 3.5"from the inside edge of the aileron. So there would be approximately 3" on one side, and 13" or so on the other side. Just doesn't make sense to me to do it that way.

 

[SnowDog]

I'm rethinking my earlier comment. Most (3D planes at least) designs keep the servo in towards the root edge of the wing because the forces will be stronger there due to the larger aileron size closer to the fuse. After looking at a few, it seems the servos are located about 1/4 of the length of the wing. Where are yours located?

 

[abaser]

Hmmmm.....that makes sense I guess. I tried to place it as close to the center as I could.

 

[abaser]

Finally had a little time to devote to the model today. I got the linkages finished up, tank mounted, and engine location marked. All that's left to finish this one up is to mount the engine, and add a tail skid. I decided against a wheel simply because im already borderline tail heavy, and I dont want to get to the point to where Im adding weight to adjust the CG.

Now for the disappointments of the day. Ive got brand new power hd servos on her. One in the wing has a constant buzzing, and my rudder servo seems extremely loose or something. Its not right at all. I can rotate the arm a couple degrees before any resistance is given. All the others are instant resistance, and seem good except for the aileron buzzer. Im really disappointed because if it weren't for those two servos, it would be in the air no later than tomorrow.:banghead::banghead::banghead: But, what can you do? Im not going to risk it due to my excitement to fly. :facepalm::facepalm:

 

[abaser]

I know this probably isn't the most accurate way to measure the overall weight, but after stepping in the bathroom scales several times to check accuracy, I picked up the sbach and gained 2.7 lbs, so I'm guessing that's pretty close to how much she weighs.

 

[abaser]

I've been looking around, but haven't found much in the line of servos that I can really afford at this moment. I'm open to suggestions for some mini, metal gear servos that won't break the bank. I'd love to give me info (recommended torque etc),but no specifics were given for this model. What I can give is this, it's a 35" ws, 2.5-3 lb, 3D model. Deflection settings are between 40 and 50 degrees with an OS 40 fp for power.

Any suggestions would greatly be appreciated.

 

[gyro]

I've been looking around, but haven't found much in the line of servos that I can really afford at this moment. I'm open to suggestions for some mini, metal gear servos that won't break the bank. I'd love to give me info (recommended torque etc),but no specifics were given for this model. What I can give is this, it's a 35" ws, 2.5-3 lb, 3D model. Deflection settings are between 40 and 50 degrees with an OS 40 fp for power.

Any suggestions would greatly be appreciated.

Have you looked at the Savox SH-0255MG servos? Digital, metal gear, lots of torque.

 

[abaser]

Those are micro. I'll check their sizes to see if they'll work or not, but all other micros have been too small for my servo trays.

I've found these, but I'm leary of going cheap again.

http://www.hobbypartz.com/33p-solarservo-d658.html#scProductReviewsws

Here's a video of what my rudder servo is doing.

[video=youtube;HsSbBLH-DL4]https://www.youtube.com/watch?v=HsSbBLH-DL4[/video]

 

[gyro]

Those are micro. I'll check their sizes to see if they'll work or not, but all other micros have been too small for my servo trays.

I've found these, but I'm leary of going cheap again.

http://www.hobbypartz.com/33p-solarservo-d658.html#scProductReviewsws

Here's a video of what my rudder servo is doing.

https://www.youtube.com/watch?v=HsSbBLH-DL4&feature=youtube_gdata_player

Sorry, I always get mini and micro confused in my head.
I used that solar for a little while on the rudder of a 48" Vyper, and it worked pretty well. Solars can be hit or miss however, sometimes they don't work out well.