The Saito 1.80 Four Stroke
|Displacement:||1.80 cu in (29.10 cc)|
|RPM Range:||2000 - 10,000|
|Engine Only Weight:||31 oz.|
|Prop Range:||15 X 8 - 18 X 6|
|Cylinder Type:||AAC-Cylinder Ringed-Piston|
|Available From:||Horizon Hobby|
seen in person
|Wing Area:||846 sq. in.|
|Weight (as advertised):||10-11 lbs|
|Weight (as reviewed):||10.55 lbs (4.785 kg)|
|Wing Loading:||28.73 oz/sq. ft.|
|Servos:||JR ST125MG High Torque|
|Receiver:||JR RS600 Six Channel|
|Available From:||Horizon Hobby|
The SuperStar was easy to assemble, though not recommended for the first time builder. Approximately eighteen hours or about two weeks of leisurely evenings were needed between getting the box and getting to the field. I attributed this quick turn-around to an extensive list of included quality hardware. Of special note was the excellence of the covering material and the first rate skill with which it was applied.
At the field the Saito 1.80 was a dream come true. Incredibly easy to start, tremendous power to weight, and very linear throttle response characterized this power plant. Saito is truly the Cadillac of model engines and I recommend them highly!
In the air the SuperStar/Saito combination proved an outstanding pairing. The SuperStar at less than eleven pounds was at the light end of the weight range for this engine. The result of this situation was a seriously overpowered craft (i.e...a 3D pilots dream)! Almost any maneuver or stunt was possible, the pilots skill being the main factor.
For IMAC and pattern purposes the SuperStar was an exceptional performer. Awesome knife edges, snaps in any attitude, and spins were of special note. The large cowl and the ability to swing an 18-6 wide prop provided excellent speed control in up or downlines. Finally, even in windy and choppy conditions, the SuperStar's large size and middle high wing loading provided superb stability in lines and maneuvers.
In the 3D realm control surface authority was simply dazzling. Hovering and torque rolls really benefited from this fact. The SuperStar was not a beginners plane! This airframe was for the intermediate to advanced pilot due to its sensitive controls and lack of forgiveness to mistakes. Overall the SuperStar was a great value and a sure bet to keep pilots challenged and coming back for more!
Since Seagull Models came on the scene they have consistently offered great looking aircraft that have been well built, great flying, light, and last but not least light on the wallet. Their latest offering, the Seagull SuperStar 1.20, seemed to hold with this tradition except on a larger scale. When it was offered for review at RCGroups I was very interested since I had been in the market for just such a model. I was awarded the project and what follows were my experiences and impressions of this semi-scale airplane.
I first began constructing R/C models in the pre-ARF era, so I consider myself an above average builder at this point in my life. That said, I continue to be amazed at the quality of construction common in the ARF's these days. I simply couldn't do any better, though I hate to admit it. As if that weren't enough, about 90% of the detail work is done for you before ever opening the box. Finally, trying to buy the hardware separately and build a plane similar to this from kit form would cost somewhere between 50 - 100% more! Ask me how I know...
The SuperStar was intended for intermediate to advanced pilots as well as experienced builders. Because of these facts I saw no reason to include an extensive build section in this article. What I did cover were a few modifications along with radio and engine installation. However, because the instruction manual was brief and assumed a fair amount of construction knowledge, I did create a build thread. If you are either considering purchasing a SuperStar and would like a preview of the build or you're an experienced pilot but a rookie builder, here is a link to that thread.
One of the first things I did was to reinforce the fuselage between the engine/landing gear section and the wing spar section. A few pilots had reported failures of that bay in between these two areas during normal operation. Fortunately a fellow author here on RCGroups clued me in on this problem before I ever received my SuperStar. Sure enough when my kit arrived it had the same defect documented in the forums. It was a simple matter to use some 1/8" aircraft grade plywood to fashion squares. I used one square to fill in the bottom bay and laminated the other two to the soft balsa sides. After the process the fuselage was tremendously stronger with negligible weight gain.
This most likely won't be a problem for current purchases as I'm now hearing reports that the latest shipments of SuperStars don't have this problem. Accolades to Seagull for listening to their customers and quickly improving their product! However, if you do get one of these earlier production ARF's, I highly recommend this simple and quick modification.
The next modification was made during assembly. The Saito 1.80 was a powerful engine for this model and the power had to come from somewhere. That somewhere was in fuel consumption. After researching the Saito's needs, the included fuel tank was going to be marginal on how much flight time it provided.
I chose to buy and install a 24 oz. fuel tank instead of using the included 20 oz. tank. According to my calculations, the supplied tank would have worked, but a lot of high throttle 3D maneuvers could have put the flight time under 10 minutes. I wanted to make sure I had plenty of air time. It was a cheap and easy upgrade that only required a few minutes of dremel work and a couple of pieces of hardwood strip. If anything smaller than the Saito 1.80 were used, this modification would be totally unnecessary.
The last modification was the location of the CG. The instruction manual instructs you to balance the SuperStar 7cm (2 3/4") back from the leading edge of the wing root. However a technical bulletin on Horizon's website corrects this by saying this measurement is to be made at the wing tip. This put the CG right on the back edge of the main wood spar where the leading edge sheeting ends. After balancing the plane at the recommended tip location, I decided to see where that placed the CG at the wing root. I wasn't surprised to find that the recommended CG balanced the plane right in the middle of the main wood spar. 5 1/8" (130mm) was the measurement to this point at the wing root. I included it in this article because balancing the plane close to fuselage was much easier than at the tips!!
Graciously provided for this review was the JR Sport Airpac that included five ST125MG 125 oz/in high torque servos, one RS600 6 channel receiver, one switch harness, one 1500mah flight battery, and two servo extensions. Also provided was a ST47BB standard servo for the throttle.
After reviewing these items on Horizon Hobby's website, it seemed that they were a fairly new offering from JR. JR, as I'm sure everyone knows, is one of if not the major player in R/C control systems. When thinking of JR one tends to think high quality. Unfortunately, many times high price also comes to mind when thinking of this brand. Not so with these new equipment offerings. JR contends that while they have drastically cut costs on these items, they haven't cut corners on quality.
After using this equipment I had to agree. The high torque servos were very quick without having to go to a 6v flight battery. They seemed to have the rated 125 oz. of torque, although I had no way of testing that fact. Finally and most importantly in my book, they had nearly zero slop and centered perfectly every time. For a 3D model this was crucial.
The receiver was very compact and light. Light enough in fact that it could have been used in park flyers if so desired. It performed perfectly with no problems detected during range testing and no perceived glitches to date. So cheers to JR for creating reasonably priced equipment that carries on their tradition of high quality!
Radio installation on the SuperStar was a breeze. There was plenty of room throughout the model for whatever equipment one might choose. Since analog servos were provided I added a servo reversing "Y" cable to synchronize the twin elevator servos. If digital servos were used or if a capable computer transmitter was available, this item would not have been needed.
Of special note were the pushrods, linkages, and control horn hardware. All of these items were top quality and quite stiff. An important necessity for a good performing 3D or pattern ship.
The 1.80 size Saito four stroke was a joy to work with from start to finish. Following the break-in instructions carefully, I erred to the safe side on how long I ran the engine extra rich while keeping the RPM's low. By the time I was ready to fine tune the big Saito, I had run nearly a gallon of glow fuel through it on the test stand. After that I gradually started leaning out the high speed needle while watching the RPM's closely with the tachometer. After a few more tanks I had the 1.80 turning the 16X8 break-in prop nearly 9800 RPM!! This was phenomenal in my opinion. Last year in comparison, I converted a 31cc weed wacker engine to model aircraft use swinging this same prop. The gas engine turned only 8300 RPM and it weighs almost twice as much as the Saito 1.80! The gas engine is flying a 15 lb plane with authority.
At this point I adjusted the valves as recommended by the manual and then bolted on an APC 18-6W 3D prop with which I planned to fly the SuperStar. This completed the break-in procedure and I retuned the engine one last time achieving a tach measurement of 8500 RPM. Still significantly more than the gas engine and with more prop. The engine had no problem idling at 2000 RPM for long periods and roared to life instantly when full throttle was applied. Throttle response was very linear and precise. At this point I knew I had a winner with more than enough power and response for any 3D maneuver.
At first glance, mounting the engine and cowling looked like it would be as quick and easy as the previous steps. However it soon turned out to be the most difficult part of assembling the SuperStar. The manual offers only a few pictures of the process. These pictures combined with some predrilled holes on the fuselage, one measurement from the firewall, and the motor mount were all the clues I had.
I installed the engine the specified distance from the firewall squarely on the motor mount. Next I trial fit the cowl using the landing gear and pictures as a guide. The predrilled holes on the fuselage were quite a bit off and the angle of the cowl in relation to the engine was even worse. After some thought I decided that the most important consideration was that the thrust line of the engine be zero degrees to the wing. I examined the roots of the wings and decided that a straight edge along the fuselage in line with the spar and wing mount holes should establish a zero thrust line.
After lining up the engine with the straight edge, the engine seemed to have several degrees of up thrust in relation to the mount. However the cowl and engine were now nearly at the same angle and the fuselage holes were closer, although still unusable. This was encouraging so I proceeded to drill new holes for the mounting screws and secured the cowling.
The next task was to install the muffler and create holes in the cowling for the exhaust, head access/cooling, fuel filler line, and high speed needle valve. The process was unique for this engine and just required a lot of patient trial and error. I did encounter a little trouble toward the end of the process. The cowl cracked on one side where it was screwed to the lower part of the fuselage. This was understandable as the glass cowl was forced to deform quite a bit as it tightened down.
I removed the cowl one last time and reinforced the four areas where screws held it to the fuselage. A couple of layers of medium glass cloth and some thinned 30 minute epoxy did the job. I Thought the end result was very attractive, very sturdy, and of course functional.
The first day at the field all checks were made and the Saito powered SuperStar was started on the safety stand. No problems were encountered and it was time for the first flight. It floated off the ground after a short takeoff run at about half throttle. However, as soon as the plane was airborne I knew I was in serious trouble. The SuperStar was barely controllable and all over the sky. A few times I could tell it was on the verge of an uncalled for snap roll. Fortunately, after a few tentative passes around the field, I was able to bring the SuperStar down with only a bounce or two. After inspection the only damage was bent tail gear.
No thought was required to understand what was wrong, ...I knew what it was the instant I took off. I was just totally surprised as I hadn't experienced this problem in several years. The control surface throws were about three times what was needed. Since becoming interested in 3D flight, I've never been able to get enough throw. This was on smaller planes though, and I made the mistake of thinking this was acceptable on my first large plane.
I spent the rest of the day experimenting with smaller throws and left the original settings on the high rate switch for future 3D maneuvers. By the fourth flight I had the throws fairly close to my liking for normal aerobatics and was feeling much more comfortable. The wind died for a short time during the last flight of the day and I was able to try a few trimming maneuvers.
My impression at this point was that the SuperStar had PLENTY of power and NO lack of control authority! I packed up for the day and later did some fine tuning on transmitter programming at the workshop.
No matter how well a plane is designed, assembled, controlled, and powered, if it's not trimmed correctly it's not going to perform well. This was especially true for the SuperStar being a large scale 3D aerobat. Since this was my first large 3D plane I decided to defer to greater experience by following the tips in this article. The process took several trips to the flying field as no-wind conditions were a necessity. Presented here is an overview of how I set up the SuperStar using the previously mentioned article as a guide.
|Aileron||3/8" up&down||1" up&down||2" up&down|
|Elevator||3/8" up&down||1" up&down||1 3/4" up&down|
|Rudder||1" left&right||2 1/4" left&right||4 1/4" left&right|
The measurements shown here were taken from the widest part of the surface.
I suggest dual rates for the intermediate pilot who uses the mild and aerobatic throws.
For those who set up the SuperStar with aerobatic and 3D throws, dual rates for all surfaces set up on a single switch is an absolute necessity!
Taking off the SuperStar required no special technique or effort. I simply had to choose between a scale takeoff or the crowd pleaser takeoff. For IMAC purposes, half throttle was the best practice, producing a short takeoff roll. First the tail would rise up leveling the aircraft from it's tail dragger taxiing position. A few seconds later the SuperStar would gently float off the ground and gain altitude without losing it's original position in relationship to the ground.
Then there was the "CROWD PLEASER" which could be loosely associated with 3D flying. The SuperStar was simply taxied to the end of the runway, lined up into the wind, and then the throttle was firewalled. What followed was a ridiculously short roll followed by climbing vertically. A handlaunched foamy could do no better!
Landings were another story. I've gotten quite used to greasing landings. And I mean every landing. I can't remember the last time I did the 'ole "Hey, that was four good landings in a row!" after one flight. But the SuperStar simply did not want to stop flying. It was like learning to land all over again. After several touch and goes I came to the conclusion that the SuperStar liked best to stay level and land on the mains with a little extra airspeed. Once the mains were firmly on the ground, airspeed could be bled off until the tail gently settled. Attempts at 3 point landings consistently produced anywhere from two to five bounces.
Ground handling on takeoff was really not an issue. The tail came off the ground so quick that the super effective rudder was steering the plane 99% of the time. However taxiing back to the pit proved to be quite a chore, until I realized high rate was needed to counter the weathervaning. The first problem I discovered was that even after a decent landing with no bounces, the tail gear would bend. This would render the tail wheel almost completely useless and the SuperStar would be all over the field scraping wing tips and trying to do ground loops. An after market tail gear was purchased and installed which helped quite a bit.
However there was still some problem getting the SuperStar to stay on track. During a particularly windy day during flight trials the problem became clear. The generous fuselage side area and large rudder were weather-vaning in the wind and overcoming the tail wheel! Once the problem was identified, I simply threw the high rate switch once the SuperStar landed. This increased the tail wheel travel and no further taxiing problems were observed.
Once the basics such as trimming, throws, landings, and takeoffs were tuned, it was time to put the SuperStar through precision maneuvers to see what it could do. Knife edges, once the pitch coupling was mixed out, were outstanding! The large fuselage side area and large aerodynamically balanced rudder were very effective. The combination provided more than enough control for any maneuver requiring yaw authority.
Stall turns fell into this category and were well executed. As the engine was throttled back and the plane lost vertical airspeed, full rudder and a slight burst of power had the SuperStar rotating around it's CG. A nice downline right back in it's flight path followed. Snaps for the SuperStar were also superior. The SuperStar's elevator was extremely effective and resulted in a quick and sharp pitch break. When aileron and rudder were then applied, the SuperStar instantly began it's rotation and the controls could be released while the plane completed the snap. Vertical snaps were just as easy with the ample power of the Saito 1.80. Even continuous snaps in any attitude were no problem for this airframe and powerplant.
Inverted flight required very little if any down pressure on the stick. The SuperStar was happy in either attitude with no tendency to snap out of outside loops. With the big Saito pulling the Superstar along, loops could be of any variety. Fast and tight, giant and slow, and lastly square loops were definitely not a problem. Spins were a sight to behold. Once again the yaw authority came into play for the SuperStar. After gaining altitude, slowing down, and adding elevator for the stall break, all that was required was full rudder and up elevator. The SuperStar would snap and begin spinning rapidly. After that the spin could be flattened as much as desired by slowly adding power and cross aileron. Spins could be maintained as long as desired and stopped just as easily. Releasing the sticks and cutting power stopped the maneuver and got the SuperStar quickly into a downline. After that all that was required was to add power back in and let the plane start flying.
The ailerons were just to my liking. With approximately half the throw available used, the SuperStar rolled smoothly and quickly. Precision rolling maneuvers were particularly easy due to the SuperStar being one of the most neutral airframes I've flown. Continuous slow rolls and four point rolls required only very slight rudder and elevator inputs and were a pleasure. With 100% throw the roll rate was insane and not really recommended for precision flight.
The one issue that kept me from giving the SuperStar a perfect score in the precision category was low speed handling. At low airspeed and low throttle, a moderate pitch change caused the airframe to drop a wingtip and perform a half snap unasked. After carefully studying it's habits at two or three mistakes high and talking with fellow club members, I identified the cause of this behavior. The general consensus was that it was due to the small area of the horizontal stabilizer and short tail moment. I also suspected the medium high wing loading due to the quad tapered wing as being part of the equation as well. It was hard to give the SuperStar a downcheck for this because these characteristics were also what allowed the plane to perform such great snaps and spins. These attributes also helped the SuperStar maintain it's great scale appearance and presence in the air no matter what the wind conditions.
After the precision flight envelope was explored, it was time to see what the SuperStar would do in post stall situations with full throws enabled. Once again, I was immediately impressed with the huge amount of control surface authority! Even with the SuperStar completely stalled and dead in the air, the prop blast was more than enough to maneuver the plane. The huge rudder and tall rounded fuselage did their job in the yaw departement providing plenty of control in any situation. The large double-beveled ailerons spanned from the tip, almost to the fuselage and thus provided adequate roll control from only the prop blast. Finally, the super effective elevator still only required about two thirds of the available travel to provide more than enough authority!
Several more flights were devoted to fine tuning the throws for 3D flight mode until I was comfortable and had the SuperStar doing it's best. Harriers were first up as my favorite 3D maneuver, but unfortunately the SuperStar suffered from serious wing rocking. Once again the tail moment/ stab area /wing loading issues were making themselves known. The SuperStar never actually snapped out of a harrier, but it's definitely not my favorite maneuver with this airframe.
Next up was hovering. After my first successful hover, the previous struggles with harriers were swept from my mind! The SuperStar required some vigorous inputs to get a hover started. However, once close to stable vertical, the airframe would "lock in" and sit motionless like a dream. The illusion of antigravity would have been complete if not for the powerful sound of the Saito churning away. Once in this mode the SuperStar required very little input to sustain a hover. I moved on to torque rolls and the SuperStar was a torque rolling monster! The ailerons were nearly too effective for this maneuver.
In fact the one time I applied full left aileron in a hover using 3D throws the SuperStar spun like a top 3 times in one second before I knew what had happened! It was a little scary, but this meant that anti-torque rolls were possible!
I suspected that with the SuperStar's excellent spinning and snapping abilities, blenders were going to be good. I was not disappointed! The SuperStar performed the maneuver blindingly fast and with extreme violence! A word of caution though, be sure to check your canopy before performing this stunt. After the flight that included my first blender was over, I discovered that the canopy had nearly been lost. The front plywood tabs were popped out of their slots and rattling around in the fuselage. I reinserted them with plenty of glue and it hasn't been an issue since.
Since the SuperStar was so comfortable in a knife edge, it seemed reasonable that it would also like high alpha knife edges. That seemed to be the case as I added rudder input, slowed the plane down, and advanced the throttle. However as the speed slowed to a certain point, the SuperStar would try to flop vertical into a hover. More experimentation and possibly some mixing at the transmitter may help this situation.
Waterfalls were a struggle and required a lot of input to keep the plane from snapping out. It was clear at this point any maneuver that involved a large pitch change coupled with low airspeed would manifest the airframe's snapping tendencies. Overall I gave the SuperStar good marks in the 3D domain despite this one shortcoming. I am continuing to explore the 3D capabilities of the SuperStar, so check back for updates!
When I was fully confident with the plane and its habits, it was time to gather some graphic material for the review. Unfortunately the weather had other ideas! For close to three weeks I waited for the wind and rain to stop when my and my wife's schedule allowed a trip to the field. Finally, one day in desperation, I made a trip to the field immediately after work just before my scheduled vacation. The weather didn't look good and it was evening, but I hoped for the best. When I arrived the weather gods smiled on me. The wind died and the rain missed the field. It was perfect flying weather though not perfect photography weather. Presented here are the results, but I hope to produce better in the coming weeks as the weather and my schedule allow. Be sure and check back in the future!
Overall I gave the SuperStar 7 1/2 out of 10 stars. It was and continues to be a very enjoyable plane to fly. To quote one of the flyers at the field, "This is like being at a full scale air show". The workmanship, materials, flight personality, and scale appearance provide in my opinion, a fantastic value for the budget minded large scale pilot. These attributes will keep intermediate to advanced pilots challenged and looking forward to the next trip to the field or IMAC contest! To wrap up, here are the highlites from the article.
Nice job on the review Jim!! Great looking plane with classic lines.
Plane was definately not lacking in power at all. I have always liked the Saito line of 4 strokes on these size of planes.
BTW - will have to remember the "Gee Whiz" and "Gosh Darn It" on my next review.
Last edited by sun.flyer; Aug 09, 2006 at 12:10 PM.
Thanks for the compliments Tim. I agree that Saitos are simply the best after having used one! This airframe just has to be seen in person to appreciate it fully and I really had a lot of fun doing the review. The weather here continues to be strange. Usually this time of the year is perfect flying weather. However we've gotten more rain in the last month than we got in the last year and a half. It doesn't even seem like the desert anymore. If all the mud ever dries up, I plan on adding a lot more 3D material to this article. I can say right now though that the SuperStar would be an outstanding airframe for someone that does IMAC contests.
I agree totally on the airframe lending itself to being a sold IMAC contest type platform. Very nice lines with the performance to match would make for a nice entry level competition airplane. Thanks for the feedback Jim.
BTW - How did your daughter(?) like the plane?
Hi i have a super star plane and it can take a 160 2 stroke or a 180 4 stroke but i want to put a gas engine in it but i do not know what size 26cc or 38cc can someone help me out here please i would apreciate the help .
Last edited by tiprat1755; Jun 14, 2007 at 09:01 AM.
Brilelli engines makes new 36 gasser that would be perfect for this plane aand they will custom make the standoffs for free. best value in gassers on the market from what i see and read. a 26 would not be big enough for this plane. search brilleli on rcuniverse.com and read the forums.
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