Tseres

Hi Andy

I have 2 sets of the drill bits that I use in sheet metal. Didn't think about using it on fiberglas. Thanks.

Tseres

Hi Bob. Glad you found us.

Bob is an old friend from the P47 thread who also has a great P47 and a Corsair.

Tseres

I tried to set the engine last night. But I'm having interference problems with the top standoffs. I'm thinking I overlooked something and will investigate and have pictures later tonight.

Tseres

Here are the pictures from Yesterday. This is why I thought that I overlooked something.
I did. The bottom of the cowl was hitting on the landing gear. I had to take 3.5mm off the back edge of the bottom of the cowl. This let the Mounting ring sit down flat on the fuse.

Tseres

Once I cut the cowl I was able to reset the engine. In two of the picks you can see how far I was off the first time. You can also see where I scribed around the standoffs with a pencil then used a divider to find the center of the circle. This method let me align the spinner in the proper location.
I tightened up the bolts on the firewall side of the Standoffs and measured the distance I needed to shim the engine forward to have clearance and not rub the back of the spinner on the cowl. In this case I have 1/2 an inch to the front of the cowl. I'll make that up in Aircraft Ply. Then I will add a flat washer between the Standoff and the ply. I may use 2 flat washers if needed to get just the right amount of clearance. I will also have to dig out some of the triangle reinforcement so I can have a flat surface for the flat washer inside the firewall. That will be next.

PS: The reason I'm going into such detail is for the new guys that haven't done this before. Cause I needed the help on my first gasser big time. Took 3 tries before it didn't crash.

Tseres

You know I'm not really surprised at things not fitting perfect on a first production run plane. I kind of relish the challenge. That don't mean that they shouldn't fix it for the next production run. If you guys find that the cowl is hitting the landing gear on your plane then post it here and let us know. You may also give a feedback to Tim so he can tell the factory.

Tseres

Got the spacers made up of some Aircraft Ply. Glued 2 pieces of 1/4 together.
Everything checks out OK so tomorrow Ill glue the Spacers in place with 5min. EpoxyThen I'll have to set up the Choke, Throttle and see where I have to rout the fuel line to the carb. Once that is done I'll pin the firewall and fuel proof what needs to be.

Bob Parker

My Feedback: (18)

Looks good Old Tom just like the rest of your planes. Should be an excellant flyer.
Bob

CannonFodder

My Feedback: (23)

Hey Tom,

Thanks for going into the detail, this will help me out tremendously. I have to ask I noticed you did not use the engine mounting template, how did you center the engine on the firewall or did I miss something.

Thanks Mark

Tseres

I stood the plane up next to the bench. Weighed the landing gear down with some led shot in baggies to hold it in place.
With the standoffs mounted I set the engine on the firewall. You have to take everything like the muffler off for the engine to balance.
Then I put the cowl on over the engine and lined it up with the spinner back plate. This is where the roughed in hole for the muffler came in handy. Then I reached in with a pencil and made some marks around the stem of the standoffs to give me something to line up to. Then I very carefully, so I don't move the engine, removed the back plate and the Cowl. Then I steadied the engine with one hand to keep it from moving and finished scribing around the standoffs on the firewall. Then I used the divider to find the center of the circle. I'll take some picture tonight and show those of you that need help using a divider on how to find center with it. I then used a small drill to drill out the center of the hole. Then a little bit bigger drill then The full size clearance drill for the screw. Using this method of drilling helps the drill from wandering off location. I've had good luck with using this method.

Tseres

Here is how to find the center of a circle with a Divider.

First you measure the circle by opening up the divider to match Circumference of the circle.

Then using a ruler find out what that distance is. 2 1/4". in this case.

Set the divider to half of the distance. 1 1/8".

Pick 3 points anywhere on the circle and draw an arc through the middle. 2 points will work but 3 is better.

You have found the center.

Tseres

Further explanation on setting the engine. I use this method because I used the cross hair method before on another cowl that had to line up on with the spinner. When I put it together it was noticeably off. This way is a little more work but I only have to do it once.
Even using a jig to build the planes don't insure you are going to have things align perfect every time. So I adopted this method to to set the engines instead of a template.

Tseres

The Heat and humidity has returned to my neck of the woods. The shop isn't air conditioned so I won't be spending much time out there.
We are having the Glass Festival here in town and I'm Signed up to work in the R/C club booth and another booth for my Wife. That also limits my time.

I did manage to get some longer screws for the firewall side of the standoffs yesterday and clear away the triangle reinforcement on the firewall. Fit the flat washers so they sit flat.
Tim Can You Help with where to put the throttle servo. Since you built one of these before, you might have a good idea as to the best location.

RedwingRC

Hey Tom

Sure!  I have the video done, I just need to upload it... It will show there too, but in the meantime

I took the servo triangle included in the kit, and glued it to the side of the firewall inline with the carb.  So it's sitting on the outside of the firewall.  I'll send a link in a bit here

Tseres

Sorry guys. Nothing got done today.
Maybe I'll do a little bit tomorrow.But I won't have time till the evening.

T3beatz

My Feedback: (4)

Nice build Tseres,

I'm really loving this sbach, it looks great! subscribed!

Tseres

Nice to see you checking in T3. Long time since I've seen you post. I still can't fly as good as you but I'm working on it.

wingburner

My Feedback: (17)

To bad you didn't use the engine template. Would be nice to know if they are actually correct. I also got stung once using an engine template, was out a 1/4". However I've built many ARF's and they are generally quite accurate. Using your alternate method works well for smaller planes.

Is the cowl length the only issue you have come across so far?

I have the Sbach and a MX2 coming. They should be here Tuesday. Then I'll decide which one to build first. Have a Syssa 30 waiting to get out of it's baggie.

Jack

Tseres

Hi Jack Glad to have you. I'd like to see the Syssa in the Sboch with a tuned pipe. Then you can go pylon racing.[sm=thumbs_up.gif]

Feel free to post your build here in this thread. It would be neat to see what you come up with. Because they are so similar,there is room here for the MX2 also.

So far the firewall distance is the only issue I've run across.

Tseres

I got the location figured out for the throttle servo.
Because my throttle arm on the carb is so low and the fact that I like to keep my pushrods straight. I mounted the servo just inside the fuse. This allows me to keep the push rod short and it will help to keep it from shaking with the vibration of the engine.
On my first gasser I had problems with my Idle and one of the guys that I flew with pointed out that the throttle rod was shaking at Idle. When I put a carbon fiber tube around the rod the Throttle problem went away. Now I try to keep the pushrod as short and as stiff as possible.

I like to modify a 2-56 ball link and tap it out to 4-40. That way I can use a 2-56 screw on the carb linkage and the throttle arm and use the stiffer 4-40 rod.. The 2-56screws and nuts fit easier in the tight places. I like to use a ball link at both ends to eliminate all the slop from the linkage. This makes the Idle adjustment a lot easier and also gives a more positive throttle response. I also solder a link at one end of the 4-40 rod so I can get the right distance for my needs at the time. I only use this method on my throttle rod. Pushrods for flying surfaces get turnbuckles or a one piece solid rod without solder joints.

This is just a positioning set up for now. I still have to solder the push rod, mount the servo and make clearance for the rod going through the firewall.

Tseres

Above pictures are fixed.

Super08

My Feedback: (2)

It's the RCU picture bug again. If you delete the post and redo it you will usually find it fixes the problem. No need to shrink the pictures.

T3beatz

My Feedback: (4)

Yeah, I've been to busy flying!!lol, now its time to get to building. Looking foward to the flight report on the Sbach.

RCplanman

My Feedback: (16)

tseres, Tom, great idea re;using a 2/56 then tapping it out to use a 4/40 rod-I'll surly use that. Bill

Super08

My Feedback: (2)

You can buy them like that from Dubro as well.