Posts: 7
Joined: 11/29/2002 From: Bethany,
OK, USA Status: offline
Hi, I have a Sig four star 120 that I am about to start building. I would really like to get into gas engines, but I am not sure if this is the right plane for gas. I have read where some have put the G23 on this plane, however I really would like to have something a little larger, such as the Fuji BT32 for future large aircraft. Is the BT32 to large for this airframe? I don't want to do something stupid on my first gas plane. All ideas will be welcomed.
Posts: 3603
Joined: 8/11/2002 From: North Hollywood, CA, USA Status: offline
There is someone on RCU that has one with a G26 and it is their club trainer/gas demo plane. I loved my 4 star 40. I think the 120 would be great with a light 40cc like the ZDZ, FPE or the BME44. IMO.
Posts: 7972
Joined: 1/31/2002 From: Ringgold,
GA, USA Status: offline
The MVVS 1.60 (26cc) would be a bolt on and would not require any modifications to the airframe. Even the balance would work out perfectly, or near enough that only moving the receiver battery would be necessary if the model is built stock.
You don't need to fly that engine with a humongous fuel tank as you would with a glow engine. An eight or ten ounce tank would be plenty for long flights.
I would not put a 40cc engine on this model unless I was prepared to do a lot of structural improvements, or I was an excellent pilot with superb throttle management ability.
Of course, if your budget is extremely limited, a Ryobi 31cc conversion will fly the model well, but there goes the building it stock option out of the window.
Check out the MVVS store links on my site at [URL]http://www.sportrc.com/smallgassers.html#Links%20to%20Small%20Gasser%20Engine%20Sites[/URL]
email them and ask them for a price in US dollars on a new red head mvvs 1.6 with the valch or falkon ignition airmailed to you.
I have both 1.6 versions, the red head is the newer version and really sweet. I'm going on my second gallon of fuel, flying every day or every second day and the engie runs like a top, flying gas over glow will pay for this engine in a couple of years.
search RCU on "mvvs" for more mvvs 1.6 info. cheers - ken
Posts: 189
Joined: 3/5/2002 From: Crestwood, IL, USA Status: offline
I'm building a 4*120 right now, just have to give it a final sanding then onto covering. Will be using a Zenoah G23 inverted for power with an APC 16x8 prop. Had to cut off the cheeks of the fuse 1/2 inch forward of the firewall as the carb & muffler mount on either side of engine & would have cut away much of the cheeks any way. The original mounting plate that came with the engine was too wide to mount it to the firewall, made a new mount from 1/4 inch plywood to fit. Will have a Sullivan Skywriter smoke pump with B&B smoke muffler. I cut the ailerons so it will have flaps, will use 4 Futaba 3001 servos in the wing. The elevator & rudder servos wil be mounted in the tail, 2 Hitec 425bb for the elevators & 1 Hitec 605 for the rudder. With the added weight of these servos at the tail I'm hoping she'll balance by moving the batteries in the radio compartment. RX will be a Futaba 139dp pcm with a 1600 mah battery, Tx is Futaba 9cap. Will do the radio programing just like my UltraStik
One of the goals in my small gasser project is to get these small gassers into narrow fuselages leading into a Spitfire or Mustang or the Typhoon shown in the photo below and not to do much cutting of the cowl, the Cap232 was my test bed to see what the small gassers could do. So far I'm pleased. I got my RCS 1.4 back from the shop and should get it going for Sunday. cheers - ken k. [URL]http://www.sportrc.com/smallgassers.html[/URL] .
Posts: 12946
Joined: 4/9/2002 From: Locust Grove,
GA, USA Status: offline
Any of the engines mentioned would work in the 4 star. Remember it was designed when the heavy 1.2ci engines were out. THE lighter gas engines will make it fly great!
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Aircraft Proving Grounds http://www.rcaircraft.net/ Information on the building and flying of Radio Control Aircraft. Site for hobbyist in the R.C. Aircraft modeling world.
Posts: 7
Joined: 11/29/2002 From: Bethany,
OK, USA Status: offline
Thanks for all the helpful information. Say, HavinFun, are you or have you already found a cowling that will work, with modifications, for your plane? I am also going to check out the MVVS thanks kenair for the web-site.
Posts: 189
Joined: 3/5/2002 From: Crestwood, IL, USA Status: offline
I did want to put a cowl on it but as the engine with carb & muffler is wider than the fuse about the only cowls that come to mind are the cap 232 & the stinger that might work.
Posts: 12946
Joined: 4/9/2002 From: Locust Grove,
GA, USA Status: offline
How about a picture of the final project and a flight report.
_____________________________
Aircraft Proving Grounds http://www.rcaircraft.net/ Information on the building and flying of Radio Control Aircraft. Site for hobbyist in the R.C. Aircraft modeling world.
I used the MVVS 1.60 (26cc) gasser in my 4 star. Flies beautifully and has as much power as I could want for it. All-up weight came to about 13.5 lb with the heavy Koverall fabric and glass and paint that I used. That includes about 1/2lb of lead weight and oversized ignition batteries I had to add to the nose to get the CG forward enough, it was actually tail heavy! My advice is don't put your servos in the tail .
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4 Star 120 Gas Engine ? - 
4 Star 120 Gas Engine ? - 
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