RE: 4*120 Build Thread
 

ok.....i think this engine looks great and fits my price range
http://www.hobbycity.com/hobbycity/s..._V2_Gas_engine

thanks guys[8D]

RE: 4*120 Build Thread
 

RCpilot: I have the same jig you are using. Have not tried it yet. Plan to on the Giant 12' Telemaster on it. Anything you have found out about use of the jig, that could have given you problems? Also have you used it on building a fuselage?

RE: 4*120 Build Thread
 

I've never used it to build a fuselage. It should work very well.

Tips? [sm=72_72.gif] None that I can think of. It's pretty easy to use.

It takes a long time to set it all up. Make sure you have the rib spacing set according to the plans. I use thin CA for wings. Once it's all set up, it only takes about 5 minutes to run around and put a drop of CA on each joint.

If you have problems, feel free to send me an email or a PM here. I'll help out. I'm sorry I'm not much help right now. My mind is drawing a blank. It's pretty easy to use and I've built a couple dozen wings on that jig. Could probably set it up in my sleep now. I've probably forgotten a few tips or secrets top make it easy to work with. [sm=red_smile.gif]

RE: 4*120 Build Thread
 

nother question......if i use this engine http://www.hobbycity.com/hobbycity/s..._V2_Gas_engine
would this prop be good? http://www3.towerhobbies.com/cgi-bin...&I=LXRF51&P=SM
with this spinner? http://www3.towerhobbies.com/cgi-bin...?&I=LXE157&P=0
thanks alot

also what would you recommend doing to make the landing gear mounts and firewall stronger?

RE: 4*120 Build Thread
 

Thats too much prop for a 26cc engine.

26cc is about 1.50 size. A 1.50 size glow engine turns a 17-8 prop +/-. And thats a 2-blade.

Now, consider a gasser makes less power than a glow engine. It will probably only turn a 16-10 or a 17-8 around 7500RPM ... not the 9000RPM you'd expect from a glow engine.

If you want to use a 3-blade prop on that 26cc engine, I'd try a 14-7 or a 14-8. My rule of thumb for 3-blade props is... drop 2" on the diameter and leave the pitch alone. Maybe, MAYBE step up 1 on the pitch, but thats generally too much load. I'm conservative on props though. I see a trend in the hobby to overprop just about everything today. Overpropping leads to heat and heat is what kills engines.

Spinner:
The 4*120 fuselage is about 4" or 4.25" wide. I'd get a spinner to match the width of the fuse. A 3" spinner is going to look kinda silly because it won't clear the cheeks on the front of the plane. But, thats just my opinion.

Landing gear and firewall:
The landing gear on the 4*120 is a weak spot. Go back to the beginning of this thread and see how I beefed up my gear plate.

I'd pin the firewall with bamboo skewers or 1/8" dowels. It wouldn't hurt to use a piece of nice hard plywood for the firewall. As I recall, the supplied wood isn't real hard. A nice piece of 1/4" or 3/8" hard plywood will stay put until the end of time.

RE: 4*120 Build Thread
 

ok...thanks alot....
so
it says on the box to use a 2 3/4 in spinner, would you go with a 4 then?
i'll go with a 14-8 prop
thanks alot again!!!!!!

RE: 4*120 Build Thread
 

heres mine so far.......i'm going to add wing tips and extra cross bracing in the wing.....
http://i438.photobucket.com/albums/q...Picture768.jpg
http://i438.photobucket.com/albums/q...Picture771.jpg

RE: 4*120 Build Thread
 

You are doing a good job

RE: 4*120 Build Thread
 

thanks...its my first build........havent even ever built an arf......just always got RTF
any other reccomended mods?...i'm also going to trim the canopy, put a gasser in it, and enlarge the rudder and elevator

RE: 4*120 Build Thread
 

You couldn't have picked a better model for your first.

Don't get too ambitious with the mods. Try to get it built correctly and neat and finished.

RE: 4*120 Build Thread
 

yeah...thanks....its going together nicely

RE: 4*120 Build Thread
 

This is one of the most fun builds I have had in a long time. With the holidays I finally got the stab put together. There is not a whole lot more I can do until I decide on a engine? I may wind up with a MDL 28 CC?
john

RE: 4*120 Build Thread
 

same with me.....i need my engine before i can do the fusalage...so i got the tail surfaces done

RE: 4*120 Build Thread
 

Has any one flown theirs with a saito 1.20? I have a new one with out a home and was curious how it would do with a heavy plane like the 4*. I also have a Brillelli 26 that will more than lilely end up in it. If anyone has any pics of the 26 in one, or has flown that setup I would like to see them.

RE: 4*120 Build Thread
 

Four Star 120's do very well with a Saito 120. You will think it is a perfect match.

RE: 4*120 Build Thread
 

On page 13 post 305 and post 310, I have pictures of mine with a G-26. Flys great and no messy clean up and a whole lot cheaper to fly on gas. The plane has a large wing to support the extra weight. I also made a few changes also. Feel free to ask any questions.

Randy

RE: 4*120 Build Thread
 

I went a head and built the fuselage.
john

RE: 4*120 Build Thread
 

looking good.......i'm getting a big order from tower hobby tomorrow with everything i need except the engine....i'm planning on doing a weed wacker conversion

RE: 4*120 Build Thread
 

I have an OS 1.08 in mine and it's a great match. Our field is at 9000' and it has plenty of power. Not 3-D, but hey, it's a 4-Star! Over 200 flights so far.

RE: 4*120 Build Thread
 

Does that count your "water landings" :)

Didn't you dunk that plane a few years back?

My friend, Pete, always says, "Every plane is good for one water landing." [X(]

RE: 4*120 Build Thread
 

It might have gotten slightly damp. but it was still a flight!!! Still flyin' great. You need to get up and fly with us again.

RE: 4*120 Build Thread
 

I bought my completely RTF string trimmer conversion engine from this guy:
www.indianatinygasengines.com

Total price for the 18cc Poulan I bought was $110, complete with muffler.

RE: 4*120 Build Thread
 

I would think that there would be no doubt about a 18cc Poulan conversion flying the plane. I don’t think You will be happy, with the way it fly’s it. How heavy is that engine? The MDL 28 CC weight is 37 oz.
Is the Poulan a bolt on and run?
john

RE: 4*120 Build Thread
 

heres the rudder so far.....i am doing the same thing to the elevator and making rounded wing tips
http://i438.photobucket.com/albums/q...MX/Picture.jpg

RE: 4*120 Build Thread
 

I was not suggesting the 18cc as an engine for the 4* 120. I was just sharing a source for converted weed eater engines. They will convert your engine for a fee. They also sell converted engines on their site and on ebay. I selected the 18cc for my Senior Telemaster build.