Teachu2

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Looking for a Sunday flier that will let me fly all day on a gallon of unleaded. Don't have a lot of building time available (who does, anymore) so I'm thinking a BCMA 26cc on a Sig 4*120 ARF might be just the ticket. What do you folks with more gas experience think?

Jake Ruddy

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Gas gets more to the gallon than that

on my 60 I can fly upwards of 30 mins on a 24 oz tank. Needless to say that combo you will probably get more than a whole weekend on one gallon

Teachu2

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Great - but is this a good combo?

Jake Ruddy

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For a Sunday flyer... sure why not. 4* will still do some mild acrobatics and will be able to have some fun. Should have some decent vertical as well, maybe not unlimited, but enjoyable all the same.

altavillan

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It's not exactly giant nor scale nor 3D. But it looks like a good combo. Landing speed might be a touch fast.

Rcpilot

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Check my build thread in the Kit Forum. I built the 4*120 in 2005 with a Ryobi 31cc conversion. I think one of the guys chimed in with an MVVS 26.

I know it's a kit build, but I don't see why the ARF would be all that much different. They are the perfect Sunday flyer. The Ryobi 31cc engine ran wide open throttle for like 58 minutes on 12oz of unleaded. That's to big for the fuel tank. I want my planes to have no more than about 20 minutes of fuel in case they fly away on me. What if it was just perfectly flat and level and it took off at full throttle? About 60MPH--70MPH for an hour? I'd be in Kansas before I caught up to it. [X(]

I'd look at an 8--10oz tank for a 26cc engine.

rc bugman

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Hi Trent,

It is good to see you back. I have a super sportser 1.20 with a 3w-24 for a similar type of sunday flyer. Very relaxing and yet it can get up and go. The 24-26 cc gas engine uses less than 1 oz of fuel per min at full throttle. Actually 0.8 oz/min.

Elson

BalsaBob

My Feedback: (24)

TeachU, Got the just the plane for you ... The .90- 1.20 Yak QB ARF by Aeroworks. The QB stands for Quick Build ! Most people are able to assemble them in 8-12 hours. I am putting a Zenoah 26 CC gasser in mine. I recieved the kit the other day, and the .26 cc is on its way. I am very impressed with the workmanship of this ARF. Check it out ! Bob

BalsaBob

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Here is the review and info on the Yak. Bob

http://www.rcuniverse.com/magazine/a...article_id=911

Teachu2

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Thanks, Bob. That's probably more of an acrobat than I want in this case.

Scar

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The president of my club had a Four-Star 120 with a US41 on the front. It WOULD hover! If you don't need to hover, I think a nice 26CC would probably run all weekend on a gallon of unleaded... and maybe leave you enough left over to drive home from the field!

Enjoy!
Dave Olson

Charlie P.

Don't forget to add some 50:1 two-stroke oil to that gallon of unleaded. ;-)


Used to be some nice "stik" style ARF gas models in 26cc size - RoadRunner and Dog House - but I don't find them on the Internet currently. Pity. How about the Giant Stik as an alternative? Not that the 4-Star is a bad choice.

Teachu2

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I do have a Jerry's Big Boy......but I think I'll hang an OS 160FX on that. Thought about the Giant Big Stik, but probably would want more motor there. The 4*120 looked like a good match.

Teachu2

My Feedback: (133)

Curious why the landing speed would be fast? The 26cc from BCMA is only an ounce heavier (with muffler and ignition) than a OS 120SurpassIII pumper. It will move the prop forward 3/4", but I think I can balance without adding lead.

Rcpilot

My Feedback: (78)

Actually it is considered Giant. At 81" span, this would fall into the IMAA legal category of 80" span for monoplanes.

It is NOT a scale airplane. So it's not Giant Scale.

Landing speeds are a breeze. About 2 clicks faster than an LT-40.

Teachu2

My Feedback: (133)

Thanks! I believe the BCMA/SPE 26cc is lighter than the Ryobi conversion, so this should work well. I'll mount the engine and tail servos first, then play with the balance by moving the rest. I plan on putting the tank back at the CG. We shall see.

Rcpilot

My Feedback: (78)

Yup. The Ryobi is heavy at about 4.5lbs. The 26 should be 1lb lighter, easily.

Teachu2

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BCMA says 36oz (2.3 lbs) with ignition and muffler. I'll have to get out the HF digital scale and see!

Taildragger726

I was under the impression that the 'scale' part of Giant Scale was refering to size,,not replication of detail. So, in my book the 4Star 120 is Giant Scale.

Rcpilot

My Feedback: (78)

Not to me.

Scale means scale. As in a replica of a full scale plane.

The Giles 202 would be a scale plane. A Giles 202 with a 73" wingspan would be 27%, so that qualifies as Giant Scale, even though the wing is less than 80". 25% or larger is considered giant.

A Cub with a 65" wing would be considered Scale, but not Giant. A 25% Cub would fall into the Giant Scale category, regardless of wingspan, since it is larger than 25%. BUT, any Cub with an 80" span would be legal to fly at an IMAA event, because of the wingspan--even though it may only be 23% in size. (really have no idea what % that would be, just using it as an example)

Since the 4* is only a model and does not represent or imitate a full scale plane--it would not qualify as Giant Scale. Only Giant. It has one wing with a span 80" or larger. How about a big ole Stick at 80" or 90" span? I wouldn't consider that Giant Scale either. Only Giant, since the Stick isn't a replica of any full scale plane.

But, I could be wrong. Thats just how I interpret it. Maybe I'll look it up on IMAA and see how they describe it.

Taildragger726

Straight from the IMAA by laws;

The purpose and goal of the International Miniature Aircraft Association, Inc. is to encourage and foster the building and flying of large radio controlled model aircraft. The term "Giant Scale" is also used by the Association to describe such aircraft. However, this term and the term "Large Scale Radio Controlled Model Aircraft," are in reference to the size of the model and not the full sized aircraft.

Rcpilot

My Feedback: (78)

Copied from the IMAA:

The purpose and goal of the International Miniature Aircraft Association, Inc. is to encourage and foster the building and flying of large radio controlled model aircraft. The term "Giant Scale" is also used by the Association to describe such aircraft. However, this term and the term "Large Scale Radio Controlled Model Aircraft," are in reference to the size of the model and not the full sized aircraft. The concept of "large" radio controlled model aircraft shall prevail over any other considerations in describing miniature aircraft. This concept of "large" is generally considered to apply to radio controlled model aircraft with minimum wingspans of eighty (80) inches for monoplanes and sixty (60) inches for multi-wing aircraft. Ducted Fan and Turbine aircraft with one hundred forty (140) inches combined length and width, measured from wing tip to wing tip at the widest point perpendicular to the fuselage and added to the length of the fuselage, excluding any protrusions. Autogyros with 50 inches for a single rotor, 80 inches for a dual rotor. Quarter (1/4) scale replicas or larger with proper documentation (minimum 3 view drawing of an actual person carrying aircraft) which do not fit the size requirements will be permitted. However, the concept does not encompass radio controlled model aircraft so large as to have the potential of carrying a human being. Turbine aircraft will have the same combined length and width requirements as Ducted Fan Aircraft. In addition, each participant that will operate any model aircraft powered by a turbine engine will sign the AMA’s ‘Statement of compliance concerning Turbine Engine Operation’ and the aircraft must comply with the AMA’s ‘Safety Regulations for Model Aircraft Gas Turbines’.

[:@] I hate being wrong.

Taildragger726

Ha,, we both learned something there! I love this hobby.

A Four Star with a G-26,,, Cool !

altavillan

My Feedback: (1)

I'll splain what will make it heavy.

Larger prop 1 to 2"s in size larger add 1 to 2 oz. OS spins at 10k gas engines spin best around 6500 to 7000
Engine mounting will be heavier with standoffs or spacer plate rather than a Drop in GP type mount Add 1 to 4 oz.
Ignition battery 1200 nicad app 5 oz.
Extra ignition switch, engine kill and related wires and mounting. add 2 oz.
Extra strengthening of the firewall. Power pulses will be much larger due to swinging a larger prop. Add 1 to 3 oz.
Larger tires to clear the larger prop. Add 1 oz.
Fuel lines are thicker clunks and filter is bigger and a loop to vent will add 1 oz.
Add a better muffler to get exhaust splatter away from the plane, add 4 oz. I have a BCMA 40 all I can say about their mufflers is, they are light.
Engine is 1 oz heavier.

For a total of 17 to 23 oz aditional weight.

I said it would be a good combo but it will sacrifice some with landing speeds being higher.
If someone can show me how to make a glow install weigh the same as a gas engine install I'm all ears.
The engine might be able to hover it. And if it does it should provide some interesting torque roll practice.
I'd be interested to hear how it comes out. Lots of guys in my club are interested in gas and this might be a good way to get them started.

Teachu2

My Feedback: (133)

Muffler already included in weight, so don't add for that. Also need to subtract for smaller tank and fuel load, although fuel load difference will be smaller on landing. The 4*120 is typically such a floater that I chopped a bay off my last one - and it still floated. I think it'll actually fly better a pound (or even two!) heavier. My last one also had an aluminum engine mount and lots of epoxy from the previous owner's close encounter with a barbed wire fence.....

"If someone can show me how to make a glow install weigh the same as a gas engine install I'm all ears." That's easy - just add lead to the glow engine!