techsarge

My Feedback: (1)

I have a 4*120 that I started a couple of years ago. At the time I picked up a new Ryobi 31cc engine, added the conversion parts and intended to use it with the 120. We now have a van and decided not to go with gas but do want to finish the plane over the winter. Am considering ordering the Supertigre G-2300 and wonder if anyone has used this combination and if so, how well it works? I have to look at the plans because I moved back the firewall about 1.5" but have to measure it again. The other question I had concerns the balance. I intended to mount the tail feather servos near the control surfaces and the rx and battery just a little forward of the tail to balance the heavy Ryobi engine. I guess I may have to move the servos forward now, right? Thanks in advance...

Volfy

My Feedback: (23)

I've got a 4*120 framed up and ready to cover. I thought about using a weedie conversion, too, as I have several different ones already converted, including Ryobi 31. I ended up framing it up the stock way and have pretty much decided to to mount one of my two ST2300 on it. One of them was originally mounted in my GP 1/4 Giles 202, but with a Bisson Pitts muffler the ST2300 just doesn't quite have the crisp throttle response that, say, a Saito 180 or OS 1.60 has. That was important in a precision aerobat, but no so much in the 4*120. The important thing is that I can use the stock muffler the came with the engine. Most ST2300 problems comes from not having enough muffler pressure with the use of aftermarket muffler like BCM Pitts.

I think the ST 2300 will be perfect for it. I would suggest you relocate the firewall back up front. Or leave the one you have on it already and just add a new one at the stock location. I don't think the 4*120 is going to notice the extra Oz of weight. I too am planning on mounting two elevator servos near the tail. I will probably do a pull-pull on the rudder. I think the ST2300 should balance them out fine, as it is a fairly heavy engine compared to the typical 4stroke 120, which I am sure is what Sig has in mind when design the 4*120.

techsarge

My Feedback: (1)

Hi, Volfy...

Thanks for responding. Guess maybe this combination isn't very popular. I know the Ryobi would do well and is very popular but the gas fumes in the minivan would be unbearable and since we only have the minivan my better half would not be pleased. I've pretty much got everything framed up too. Have to get some sanding done b4 I cover. Probably will use ultracote. Moving the firewall back forward would be tough as I used some small dowels and triangle to reenforce that area for the Ryobi. When I get the ST, I'l measure and probably either build a box or just use some aircraft ply to bring the forewall back into the right position. What's your opinion on the ST G2300? Originally, I kicked around using a TT 120 but then opted for the Ryobi. Which prop will you use? How are you mounting the engine? I thought about chopping off the cheeks and mounting it sideways and looking for a pitts style muffler.

When I get the engine and get it mounted, I may mount the wing and temporarily mount the servos in the back as I had originally planned and check the cg. A little lead up if necessary shouldn't be a problem. Only been in this hobby a couple of years so if you don't mind I may shoot a few questions your way.

Thanks...

Ed

Taildrager-inactive

My Feedback: (11)

I used a lightening hole on the bottom of fuse to mount my elivator & rudder servo. Worked very well as easy to adjust.

techsarge

My Feedback: (1)

Thanks, Taildrager. I filled the lightening hole on the side of the fuse near the tail identically to the way you did it. That compartment was supposed to be for the battery and rx. The two servos were mounted on either side outside of the fuse near the tail. That was supposed to help balance the Ryobi. Now that I've decided to go with an ST G2300 instead, I'll probably have to move the servos forward along with the battery and rx and have to build up the firewall to place it back in its original position. I think you and I exchanged some messages on the 4*120/Ryobi a couple of years ago when we were in the process of building. How do you like that combo? Thanks for the photos and keep in touch...

ED

techsarge

My Feedback: (1)

Sorry. This is a duplicate post...

Ed

b100

just finnished a 4* 120 with the g-2300. i mounted the servos in the tail & glassed & painted the fuselage. came out very tail heavy. took about 2 lbs. in the engine compartment to balance at fwd c/g. flys pretty well , but not over powered. i think with the firewall moved back the ryobi would work well.

techsarge

My Feedback: (1)

B100...

That's what I'm afraid of. Looks like I''ll have to move the firewall forward back to its original position or add some aircraft ply to fill in the space I gained when I originally moved the firewall back for the Ryobi. Looks like I'll also have to move the servos into the servo compartment to avoid using lots of lead. I appreciate your input and it will save me some time...

Thanks...

Ed

Taildrager-inactive

My Feedback: (11)

I went with a RCS 140 and does very well on the 4* at 12 pounds. really fun plane and lands at walking speed. I might cut off 1 bay of each wing some day for better roll rate and less of a floater.

rogue-RCU

My Feedback: (2)

I have been flying mine for a year and a half with an ASP 1.08 with wildcat 15% nitro and it flys just great . It is my first plane of this size.

KingCobra

My Feedback: (17)

I've got a 4*120 running the Thunder Tiger Pro 120 and it is plenty powerful for the plane. Finished out to 10.5 lbs. The TT120 with a 15X8 MAS prop will pull it vertical with no problem. 15 minutes of flight burns about 16 oz fuel. Great airplane! Next I want to sidemount the engine and adapt a cowl onto it.

techsarge

My Feedback: (1)

Taildrager; Rogue-RCU; KingCobra...

Thanks to all for the information. Sounds like the ST G2300 is in the same general power class and should pull the 4*120 fine. Just looked at the airframe yesterday and now I remember I decided to put in a hatch for the fuel tank. I'm in the process of figuring out how to make it strong enough and the best way to secure it to the fuse. I did put a layer of fiberglass on the underside of the hatch. May just put a second layer for the added strength.

Ed

Taildrager-inactive

My Feedback: (11)

I also made a hatch in front for my battries and ingnition box. I never thought of glass, just made a X with 1/4X1/4 sq balsa on the hatch cover. My gas tank is located on the CG above the wing on a piece of 1/8 ply that is removable. In this way I never have to trim weather the tank is full or not.

techsarge

My Feedback: (1)

The hatch cover seems to be fairly strong with the glass. I also put 3/16" square balsa on either side of the hatch parallel with the fuse sides. The length of each is about 2"; did this to kinda keep the balsa tight up against the fuse. I epoxied 2 pieces of 1/2" aircraft ply in the back corners of the hatch at the fuse at the former at rear of tank compartment (F2?)and tapped each for a 6-32 bolt. Trying to decide how to do it to hold down the front of hatch. I may just use a piece of ply as a platform epoxied against rear of firewall and tap the ply to accept another 6-32 bolt. Putting the fuel tank at the cg sounds good but you have an advantage with the gasser and the carb pump. With the G2300 I don't have that luxury and from what I've read the tank should be as close as possible to the engine. Did you use an anti-vibration engine mount like Dubro or did vibration appear to be a problem? I'm a little concerned with vibration and the fact that I am using a hatch cover instead of a solid piece of balsa tying everything together. Any comments on vibration, Taildrager?

Thanks...

Ed

Taildrager-inactive

My Feedback: (11)

Yes the little gasser does shake a bit if the idle gets too low, or on first start up till she warmes up. I did use a Do-Bro anti vibration beam mount, but would have mounted solid had there been a solid mount available. Here is how I mounted the front hach cover with a screw on each corner.

techsarge

My Feedback: (1)

Ok. I'm putting the hatch on top but in retrospect the bottom would have been more out-of-sight. I'm thinking of adding some small formers running across the fuse under the hatch for support and to prevent much flex up front. I don't want to turn this into a major project cuz it shouldn't be. That Dubro mount is nice but not real cheap. I think I may go with the GP adjustable mount of the correct size. Also will have to use some ply to move the ST out enough to clear the cheeks and for proper balance. I think the ST G2300 weighs in about 38 oz. with muffler. I'd imagine a 120 4 stroke would be a little lighter. I'm going to try to leave the blind nuts for the Ryobi mount in the firewall in case I decide to use the gasser later. Thanks for the pix and I'll try to take some when I get my digital back from my daughter...

Ed

Taildrager-inactive

My Feedback: (11)

I did not want to cut into my pretty sheeting & covering job on the top for a hatch. The bottom was very easy and just made for a hatch. My motor weighs abt a pound more than yours, and I use a 20oz fuel tank. Some day I would like to build another 4*120, and thin the ribs for a thinner airfoil, cut a couple of bays off the wings, different canopy and generally bash the heck out of it making it faster lighter & more aerobatic with a 50cc engine for grins.

b100

techsarge

the engine mount that comes with the four star fits the g-2300 perfectly. since my last post i've been able to reduce my balast weight down to a little less than a pound, by mounting the battery pack on the cowl cheek & moving the engine forward. i think my total weight is about 14 lbs. it's not fully broken in yet but so far the g-2300 runs great. i've had my fuel tank out a couple of times, and even without a hatch it's pretty easy.

techsarge

My Feedback: (1)

Taildrager...

I hate to do that, too. I've read in some other posts that putting in a hatch can weaken the fuse and I'd sure hate to do that. I'd like the plane to last for awhile. Wow, with a 20 oz tank with a gasser you could probably fly for a good long time. I thought about cutting a couple of bays off but I think I'll leave it as is for now at least until spring when I can get it up in the air. I had a 4*60 which I thought flew great. Built it kinda heavy but it was solid in the wind. Hope this one handles the same way.

Ed

techsarge

My Feedback: (1)

b100....

Thanks for the information on the mount. I used that mount for another plane/engine but I've put the mount on my xmas list. Did you notice any change in its flying characteristics after it shed the pound? Have to think there was a difference. It's good to hear your experience with the 2300. Never owned one and generally the guys I fly with don't choose Supertigre engines. I've read lots of posts from happy owners especially the new Chinese engines. Guess they changed the carb to get a good midrange response. What size fuel tank did you install? Not sure which size I'll get. Stil have to decide where to mount the servos. Hate to leave them in the tail and have to add weight up front. I have some time before I have to make that decision. Still working on the hatch. I'll know more when I have the engine. Probably didn't need to make a hatch but didn't study it close enough. Thanks and keep in touch...

Ed

b100

techsarge

haven't got a chance to fly since the weight loss ,either too windy too cold or both. ive had two different tanks , i started with a 24 oz then switched to a 16 oz. the 24 oz was a snug fit & probably more capacity than needed, [18 minutes full throttle very rich] haven't run it yet with the 16 oz tank. your balance may not be as far off as mine if you leave the servos in the tail i kind of got carried away with epoxy beefing up the tail. if i built another i would stick to the plans & try to keep it light , but even heavy its a great flying plane.

Taildrager-inactive

My Feedback: (11)

You will like this one. had my 4*120 all done, put her on the ballencer to check the CG and the tail hit the building board like a ton of bricks, so after installing both batteries against the fire wall she was still tail heavy. After thinking about it for a bit and taking off the motor, grabed a pine 2X4 cut to the right length, drilled 4 holes that matched the fire wall holes, found 4 longer bolts, hit the face of the 2X4 with a little 220 sandpaper, mixed up some thinned epoxy, brushed it on, and after it dried bolted the engine back on and she ballenced perfect. In a year of flying only had one guy ask " is that a 2X4 on the front of your firewall". I replyed " who would put a 2X4 on the front of a firewall".

techsarge

My Feedback: (1)

Hi, Taildrager...

That is funny!! And the best part is that it worked. Last night I finished up on the hatch for the most part. It's a lot more elaborate than it needed to be. I was going to glass the entire top of the hatch also but opted instead to put a 2" strip of 6 oz glass on the center from front to back. Have to build up the balsa above the firewall a little and it should be fine. Heck, probably should have left well enough alone. I'll keep you posted....



Ed

Taildrager-inactive

My Feedback: (11)

I did purchase the longer TNT landing gear, but have yet to use it as have not bent the stock gear up enough to warrent it's use. Have a little Fuji 32 nib I would like to break in on the 4*. It would add a couple of pounds along with the new gear, as it swings a 18" prop but would be fun to try before bolting it on the Midwest T-6 that I am building. I think the 81" wing would handle the the added weight, as that would make this bird come out at 14 pounds. Don't think I could hang the 4* on the prop, but sure would give her some poop on the vertical.

techsarge

My Feedback: (1)

When I was building the 4*60 a friend who had one suggested getting nylon landing gear as the original gear eventually flattened out. I decided to try it since some of my landings are a little less than perfect. It worked out well and had the Saito 91 pulling it around. Sounds like the 4* with the fuji up front would be a good combination. Haven't seen the Midwest T-6 but I'll bet it will be nice. I thought about a warbird but the retracts are pretty expensive and I'm afraid I'd be spending a lot of down time with that bird. Heck, maybe one of these days. Got the ST G2300 yesterday so I'll be back in the shop now figuring out whether I'll need to put some ply to extend the engine past the cheeks or whether it just might be ok. Then, of course, the balance will be another issue. Take care and talk to you soon..

Ed