4*120 Build Thread
#876
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Using the heat gun to soften up the epoxy is a good idea. I wish I would have thought of that. Might have saved me some work and time. Got the wings succesfully epoxied together last night. Will start the fuslage build tonight. That will be nice to move on to something new.
Has anyone moved the firewall or just added an extension to the front of the firewall in order to move the engine mount more forward to help shift the balance and prevent tail heavyness? I'm still concerned about a tail heavy plane that I would have to add dead weight to the front to balance. Are my concerns unwarranted with a 32 oz motor and accessories? As I build the fuselage that would be the time to do this.
Lamar
Has anyone moved the firewall or just added an extension to the front of the firewall in order to move the engine mount more forward to help shift the balance and prevent tail heavyness? I'm still concerned about a tail heavy plane that I would have to add dead weight to the front to balance. Are my concerns unwarranted with a 32 oz motor and accessories? As I build the fuselage that would be the time to do this.
Lamar
#877
I used a pull pull on the rudder when I built mine. If your servos are in the stock location, you probably will balance with very little lead up front. Like I said on mine I put a servo in the tail, whats that ratio, 2:1? add an ounce to the tail, takes 2 to balance in the nose? I will go downstairs later and pull the hatch off to see how much I had to add, keep in mind I feel mine is still nose heavy and needs to be re-balanced on the Vanessa.
#878
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I've got my engine and mount attached to the firewall. On step 34 of the build manual it's mentioned to drill a hole in the firewall now for the throttle pushrod. I'm going to need a lot more holes than that for other things like choke push rod, sensor lead, fuel line, spark plug cable. Shouldn't the fuselage be built first before any holes are drilled in firewall.
Also for the choke pushrod, I want a manual push-pull set up, and I was thinking of a rod at the bottom of the fuselage behind the fire wall. The angle of the choke lever doesn't seem ideal on this engine and I could use some advice on ways to set this up.
Lamar
Also for the choke pushrod, I want a manual push-pull set up, and I was thinking of a rod at the bottom of the fuselage behind the fire wall. The angle of the choke lever doesn't seem ideal on this engine and I could use some advice on ways to set this up.
Lamar
#879
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I put an L bracket under the front engine mounting with a grommet that I run a wire to the choke arm up to just behind the prop. Forward is run, in is choke. Your arm looks like it is swagged on at a different angle then my DLE 20.
If you want just consider other directions for the rod then back into the fuse. Straight out the cowl cheeks or at an angle for better pull push ( 45* to 45*)
Sorry I cann't post a pic right now.
If you want just consider other directions for the rod then back into the fuse. Straight out the cowl cheeks or at an angle for better pull push ( 45* to 45*)
Sorry I cann't post a pic right now.
#880
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lamarkeiko
I was looking something up and ran across this: check out post 13 another nice way.
http://www.rcuniverse.com/forum/gas-...-question.html
I was looking something up and ran across this: check out post 13 another nice way.
http://www.rcuniverse.com/forum/gas-...-question.html
#882
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Thanks for the ideas. I think the simplest way is comming out the side at a 45 deg. angle, given the angle the choke arm is attached. I tried attaching a ball connector to the choke arm using some Golden rod, and I could push pull the choke open & closed very easy at that angle. I should be able to make a clean exit out the side of the fuselage.
Lamar
Lamar
#883
I will get some photos of my DLE20 setup to help guide you on your endevor. The pickup lead goes through the top of the firewall, and the ignition comes out the bottom of the fuse where I made an access hatch. I'll post them tomorrow.
#884
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Hey acdii,
I was hoping you would post those pictures you mentioned. I definately want a bottom hatch to access my electrical, and would be open to ideas on how to make it. I'm also considering a top hatch for the fuel tank.
I was reading back about a year ago acdii on this thread, and you mentioned your 120 build came out at over 13 lb. What covering did you use? Was it Koverall, and what did you use for paint? I'm planning on using Koverall, so I'd be interested.
Lamar
#885
For some reason I cant get my pictures to post. I uploaded them twice from my phone, but I have yet to see them, I used SIG covering on mine, so the blue dope matched perfectly . Can't get the SIG covering any more though.
#887
Hey Lamar, concerning the lower hatch, the panel right in front of the landing gear is a perfect place to put one in. Here's what I did...
Last edited by brockettman; 11-26-2015 at 08:38 AM.
#888
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Um.. gassers put the fuel tank right on the CG (right over the wing). This gives the greatest choices for the batteries and ignition location. While giving a CG that never changes during flight.
You have to love that fuel pumps advantages.
You have to love that fuel pumps advantages.
#889
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I spent some time last night laying out what I have to install, and trying to figure out the best layout.
I have my electronic ignition, Rcexl Opto kill switch, Rcexl mini tachometer, 2300 ma 4.8 volt ignition battery, a 2300 ma 6 volt receiver battery, and a 12 oz fuel tank. I want an outside fuel dot, reciever switch and manual ignition switch. I was never considering having the fuel tank over the CG. I had just figured on installing it in the traditional fuel tank compartment and trying to fit the batteries and electronic ignition in the lower compartment. Is there really going to be much change in flight characteristics if the fuel tank was not over CG? I'm just asking. I would think if this was a precision pattern or 3D plane, that may make a difference.
I'm attaching a couple photos of my equipment. My tank floor isn't glued in yet, and I was also thinking of dropping the floor aboue 3/8" to help give my throttle linkage clearance. The throttle arm now is just about in line with the tank floor per plan. I'm very open to ideas now, so please reply back and post pictures if you have them.
Lamar
#890
Lamar,
You will be fine putting the tank in the forward position per plans. kmeyers is right that typically in gassers the fuel tank is on Center of Gravity. I moved my servo mount back and put the gas tank over the wing behind the landing gear mount. Also another picture of the "hatch".
You will be fine putting the tank in the forward position per plans. kmeyers is right that typically in gassers the fuel tank is on Center of Gravity. I moved my servo mount back and put the gas tank over the wing behind the landing gear mount. Also another picture of the "hatch".
#893
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Brockettman,
I like your bottom hatch and how you have your plug cable comming out. Did you just leave out the tank floor and have one big compartment there, or do you have another level I can't see. Also, where are your batteries located, and how did your CG balancing make out? Did you have to add nose weight? What engine are you using? Lots of Questions huh. I'm trying hard to keep from adding nose weights for balancing.
Lamar
I like your bottom hatch and how you have your plug cable comming out. Did you just leave out the tank floor and have one big compartment there, or do you have another level I can't see. Also, where are your batteries located, and how did your CG balancing make out? Did you have to add nose weight? What engine are you using? Lots of Questions huh. I'm trying hard to keep from adding nose weights for balancing.
Lamar
#894
Lamar,
I have a Syssa 30cc engine up front with ignition and battery in the compartment behind the firewall. I moved my receiver battery back from the wing about 8 inches to balance the plane with no additional weight. I moved the tank floor back and used it in the modified tank location and left the front compartment open. The scoop on the front of my plane actually takes air into the front compartment where it flows into the carb intake through a hole in the firewall.
Build well!
Ben
I have a Syssa 30cc engine up front with ignition and battery in the compartment behind the firewall. I moved my receiver battery back from the wing about 8 inches to balance the plane with no additional weight. I moved the tank floor back and used it in the modified tank location and left the front compartment open. The scoop on the front of my plane actually takes air into the front compartment where it flows into the carb intake through a hole in the firewall.
Build well!
Ben
#895
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Well,i found the 120 engine for a steal and figured it would be a good match for the 4*120, what I'm looking for is to practice some pattern moves, nothing more.
If it will pull the plane that's all I need.
If it will pull the plane that's all I need.
#896
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Thanks Brockettman for the info. That Syssa 30cc engine totals about 10 oz heavier than my 20cc Valley View engine, so I can see how you got away with out adding nose weight. Your cowl build probably also added a couple oz. of nose weight. How do you like that Syssa engine? I was really looking at that one a lot, because I wanted Made in USA. Because I've never used a gasser before, I couldn't justify spending that much for my first one.
Lamar
Lamar
#897
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lamar
The problem with tank position is: tank forward you have to balance with a full tank. Over the CG you can balance with an empty tank.
The change in trim during the flight is small (6 oz in the forward tank position), but, you can tell (maybe one reason guys think they are floaters).
The problem with tank position is: tank forward you have to balance with a full tank. Over the CG you can balance with an empty tank.
The change in trim during the flight is small (6 oz in the forward tank position), but, you can tell (maybe one reason guys think they are floaters).
#898
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I finally managed to make a little progress. I finished making a bottom hatch. I used a little of Brockettman's idea with a little of my own. I'm pleased with the results. Got my left cheek cut out for muffler clearance. I didn't have much to cut.
I made a new fuel tank floor, and lowered it in the compartment so the tank fuel line will have a straight run to the engine.
I now need to make a top hatch for the fuel tank access. I'm sure I'll come up with an idea, but if someone has done this before, I'd appreciate some photos of how you did it if you have them.
Lamar
I made a new fuel tank floor, and lowered it in the compartment so the tank fuel line will have a straight run to the engine.
I now need to make a top hatch for the fuel tank access. I'm sure I'll come up with an idea, but if someone has done this before, I'd appreciate some photos of how you did it if you have them.
Lamar
#899
Lamar, your set-up looks real good. The Syssa has run very good for me so far. I still need to put some time on it to get it run in. I still have less than 1/2 gallon through it!
Build well!
Ben
Build well!
Ben