JoeMamma

I really don't know. As I mentioned in an earlier post I did a preliminary CG test at 4 7/8" using my Great Planes CG tester. The test was done two ways; right side up and upside down. It showed this particular Sbach to be very nose heavy ??? So, I plan on continuing to add weight to the rear.

I was just studying the front end structure of mine and remembered doing a total rebuild and reinforcement of the engine mounting box and the firewall. I did this reinforcement because of past experiences with the O.S. 1.20AX. It's a real powerhouse engine (this will be my fourth 1.20AX......I'm currently still flying three of them).

I also used sheets of balsa to cover up all of those big gaping holes at the front end because I didn't want to get glow fuel residue all over the inside of the fuse. What a chocolately mess ! Right now there is no way to tell, but I'll bet I added a lot of weight to her nose.

Hey, I never said I build light ! Anyway, I tend to fly more pattern type maneuvers and don't do many hovering type maneuvers, so the extra weight usually doesn't show up in my flying style.

Joe M.

JoeMamma

Are you in a cold or warm part of Texas ?

Joe M.

Bcolici

JoeMamma,regarding your nose heavy issue, as I recall
you also didn't install the 2 servos for the elevators in the rear location.

I don't mind the rough look of the servos being exposed out in the back,actually I like to see the servos working back there.
Im not a fan of the pull pull rudder though,not yet anyway as this is my first.
What I really dislike is the clear covering that some of the electric planes use. Cause that's what I want is a transparent plane to fly. Lol.

Enjoy the winter weather while in Florida cause the summer is just too hot,for me anyway.

rekit500

I'm close to Houston-a/c one day, heater the next. Spring and fall are like 2 weeks long, ehhh. I had one of those "transparent" planes, what a brilliant idea. grrrrr. Had to add covering for orientation. Looks cool to a kid I guess. The Funtana 90 I have, it's balance point is quite a ways behind the wing tube if I recall, but it did fly tail heavy. Never really liked the way it flew, kinda dragging it's ass around. But it never snapped or misbehaved. This SBACH may be similar, but the wing is more like an Edge. We'll start at the spar and venture back

Bcolici

If anyone is worried about finding the right cg for this plane i posted a link somewhere in this thread to make a unit that finds the cg.
I just don't have the time or space at the moment to make one

I can find it if anyone is interested.

I got my dual elevator servos and the linkage setup last night. The Futaba 7c 2.4 makes it easy.
Going to get the ailerons done and attempt the pull pull rudder that ive been putting off ,tonight.

JoeMamma

Your probably correct about the weight of my single elevator servo and changing the location of that single servo more forward. That issue along with my engine box/firewall reinforcements is driving my CG more nose heavy. As I just mentioned yesterday, I'm not really worried about it.

Florida ? Guess I'm looking for the best of both worlds. Would never want to live year-round in FL........too ungodly hot for me ! Can't seem to stand the cold anymore, but I actually hate the Florida summer heat even more. We have had some very nice summers here in Michigan.

I remember the old expression: "Only mad dogs and Englishmen go out into the noonday sun" (I think I got that right).

Joe M.

JoeMamma

Thanks for the info, but I'm still looking for an Sbach CG guinea pig.

Joe M.

rekit500

If you've been following this thread you know I bought two of these. The wing tube on the second one is really tight, so I CA'ed a disc of balsa with a bolt in it and spun it with a drill to sand it. I had gloves, glasses, and a jacket on with a fan blowing that stuff away from me after reading the post above. Here's a pic. I also moved my throttle servo to better accommodate the Rotoflow. I probably could have fitted the 12oz. Pic's. Just need some good weather.......

JoeMamma

Lookin' Good ! Glad to see you are coming along nicely !

The fit of the wing tube on mine was really bad. Not only was the fit of the main tube into each wing panel very bad, but also the female tube inside the fuse was not centered correctly on the fuse. I spent a lot of time repairing mine.

I used to do a lot of automotive brake work back in the '60's and still have a set of different size silicone ball hones. The hone attaches to your handdrill and works great on the insides of female tubes. You just need to be careful as the hone will remove material quickly.

Here's a typical 180-grit 1" silicone ball hone sold at Summit Racing http://www.summitracing.com/parts/brh-bc10018

Joe M.

tailskid

My Feedback: (34)

He he....flew my 30cc Fun Fly Sbach again today.....sure is a nice plane....cough, cough......and it was COLD too boot....only got up to 52 this morning, but we are going back into the 70's this week.

rekit500

Thanks Joe. What part does the silicone play? You dress it with compound I guess?

JoeMamma

Gritty, hardened silicone is the material used to make up the little balls on the hone. When doing automotive brake work, I use a little brake fluid applied to the hone balls to help the honing tool cut through a metal cylinder bore.

If you will be using this tool for wing tubes, omit the fluid and do the boring dry. It's a great way to slightly open up a female aluminum or carbon fiber wing tube. Just keep the drill speed slow when boring while constantly moving your drill in and out of the tube.

After making a few passes with the hone, clean both the male and female wing tubes and insert them together to be sure you aren't removing too much material. Sometimes just a few passes with the hone will be sufficient, but multiple passes may be necessary. Again, check bore clearance frequently after boring.

One of the problems I had with the glued in, fuse mounted wing tube on mine was it was out round by at least 0.003". Three-thousenth's is quite a bit. It's just another Chinese quality control issue.

Joe M.

rekit500

I always struggle with mounting stuff-where, how, do I need to remove it often, etc. After several tries I came up with this, I think it's going to work well. I didn't want zip ties on the tank as I will need access to the batteries below sometimes. I can't seem to get velcro to tighten as well as I'd like. So this panel goes over some foam on the tank and the rear lodges under the fuslage crosspiece. Then press the front down and the strip of wood slides over it and thru the holes already in the fuslage. It's length is such that when the canopy goes on, It can't slide out. No screws, no glue, no B.S.

JoeMamma

If you are involved in this great RC hobby, you will usually always need to be some kind of a designer.

Your idea looks like great ingenuity to me ! I had to study your pics, but it appears you are using the foam as a spring tension device to hold your wood plate in position.

Keep up the good work !

Joe M.

rekit500

Exactly. And foam in the compartment above and below the batteries along with some wood "stops" to keep the batteries in position. There is a lot of leeway fore-aft for CG experimentation there.

Bcolici

Some pics of my progress.

JoeMamma

Lookin' good. Appears she's getting close to being finished up ?

Joe M.

Bcolici

Thanks.
She needs a motor and to finish installing some electronics.

tailskid

My Feedback: (34)

I love the way the color changes with each pic.

Bcolici

I didn't even notice the color change until your mention of it.
Strange as they were taken with the same settings just at different angles.
Oh wait,Actually i shut the flash.

Tailskid how long before you maiden her?
Also ,what kind of throws do you have setup on the control surfaces?

JoeMamma

I'd also like to know.

As Groucho would say: Todays secret words (woids) are "center of gravity" !

Sorry, if you're younger than 50-55 you probably would not understand who Groucho is.

Joe M.

Bcolici

About 5 yrs younger than 50. Lol
I believe you're referring to Groucho Marx.

tailskid

My Feedback: (34)

I have flown that puppy a bunch of times.....one growing machine....when I get my computer back, I will post some pics.

JoeMamma

Hi tailskid,

If you have been following this thread, you will know that the CG setting and flying surface throws are about non-existent. Troy Built Models supplies nothing so you're on your own.

I'm just about finished with mine. Still need to adjust all of my throws, high/low rate settings and expo. settings. Also have not yet set CG. I currently have my initial CG set at 4 7/8".

Can you please give us ALL an initial CG setting ? Also some initial throws for elevator, rudder and ailerons ?

Joe M.

Bcolici

Ohh sure, get it flying and abandon us. Lol j.k.
Please do post c.o.g. and control surface throws.
A quick video with youre phone will do.
Edit. Thought you were rekit. Whos has the tbm 342.