My Sun Racer ready to fly.
|Wing Area:||160.01 sq. in.|
|Weight:||20 oz. RTF|
|Servos:||2 Hitec HS-56HB|
|Battery:||Apogee 2170 3s1p|
At the 05 AMA show I loved looking at all the molded models being displayed by Soaring USA. I had a nice collection of gliders both large and small but the one nitch that was empty was a truely hot plane. Something that was fast enough to scare me! Fortunately, as I have gotten older, it takes less speed to scare me and make me happy. The Corvette I had as a young man has been replaced with a Prius today (love that mileage and its brushless motor is really great). I loved the looks of the little Sunracer they were selling ... with a wingspan of 38.5 inches it is an F5D pylon racer. In talking to them, I learned that -- outfitted with the right motor -- it could maintain speeds in excess of 165 miles per hour in level flight. But at that speed you have to constantly turn, climb or dive or the plane will soon be out of sight. I also learned that they were selling the new improved Sunracer with even more Kevlar in it for greater strength than the 2004 model. It was so good looking that I decided to buy one.
I understand that most people who buy this plane would place the hottest motor they could afford/fit into the fuselage. I thought about doing that but I decided to go a different route, to make the plane what I wanted it to be. I decided to go for a 100 mile per hour plane. The Sunracer's wing is much easier to see than that of my former speed 400 pylon racer (38.5" vs. 27"). I also calculated that, with my flying style, this set-up would give me more than double the flying time that a faster motor going all out would supply. I personally would have more fun flying the plane in my manner, rather than just making constant left turns at full speed. So I equipped this plane to fit my needs.
The kit includes a molded carbon/Kevlar fuselage that was reinforced in late 2004 with more Kevlar for even more strength than the original model. The fuselage comes in two parts as shown in the picture below. The main body from in front of the wing through the tail fin and the nosecone that slips into the body and is secured in the bottom with a small screw.
The wing came in one piece and was hollow molded with a carbon spar. It came complete with hinged ailerons and pre-installed aileron linkage. The horizontal stabilizer came with the elevator already installed as well.
There was a very small bag of hardware that included: three small bolts for mounting the wing and one smaller bolt for securing the nosecone to the fuselage. There was a control horn for the elevator and a bent wire to connect it to the elevator servo that was mounted into the tail. There was even a molded "circle" to cover the elevator servo. Finally, there was a ball linkage and a small bolt to secure the ball into the servo arm to link-up one servo with both ailerons thru the preinstalled linkage.
There were no instructions nor information with the kit. The lack of instructions is very common with higher end products of limited production. While I didn't need any instructions for this project, I always enjoy seeing them in a kit whether I need them, read them or not.
For power I used a Kontronik 400-23 direct drive with a Smile 30-6-12 speed controller. According to motocalc this combo with a 4.7 x 4.7 Graupner Cam Speed prop should be capable of powering this plane at or above 100 miles per hour in level flight. Since I had this motor and controller combo on hand and I loved the efficiency and quality of the Kontronik motor, it was selected for use in this plane. Other Kontronik motors could have been selected or even other brands to get more speed but I was building this plane for me and what I felt I would be comfortably scared flying. Besides if 100 miles per hour ever proved to be boring to me (fat chance) I could always move up in my choice of power. Bob from Soaring USA told me that with the right combo this new stronger Sunracer could go 170 mph in level flight. Based on my reading in RC Group forums I ordered a Jerzey spinner and that proved to be a great custom component!
Servos were the next item for my consideration and I looked in my servo box and saw a nice supply of GWS Naro and Hitec 55 servos and while both are excellent for park flyers they really were not designed for the type of pressure that can be placed on a servo in a high speed plane. (If one servo could handle every job we wouldn't need such a variety of servos.) For the elevator especially I chose the than new Hitec HS56-HB micro servo with the Karbonite gear train that were advertised as being 4 times stronger than Hitec's normal white plastic gears. I liked the speed and torque of the servo but the strength of these gears as advertised caused me to decide to buy them. Fortunately, this project only required two servos and while they are not expensive it all does add up. So based on info from the internet I ordered a pair of these servos. After the servos arrived and I checked them out, I ordered some more for my Trex 450 review.
Battery Pack Selection was my final consideration and acquisition for this project. I have had tremendous success using Apogee Lithium batteries in many of my planes and Trex helicopter. I went with the Apogee 2170 3s1p pack. It easily fits into the back of the nosecone area.
The only real "assembly" was gluing the molded horizontal stabilizer into the fuselage. Other than that it was merely installing radio gear, motor, speed controller and battery. This plane comes almost completely finished and very nicely finished at that. But since there were no instructions I will cover the assembly and installation fully. Additionally I did two modifications to get things to fit and work properly. My modifications involved the aileron servo mounting platform and lengthening my elevator control rod.
The wing arrives completely finished. I thought that all I had to do was determine the proper length for the servo arm to fit properly into the wing and then secure the ball link for the aileron linkage to the servo arm with the supplied small bolt. Snap the ball into the linkage with the servo arm in the neutral position (With the servo plugged into the receiver and the radio system active.) Then glue the servo into the wing. However when doing my final practice fit I noticed that my servo (Hitec-56) didn't fit on the preformed mounting ledge when connected to the aileron linkage. The servo was about 1/16 of an inch to long for the mounting ledge. To solve that I got out my Dremel like tool and ground away about 1/16th of an inch of the fiberglass behind the platform so that the servo would fit on the platform flat with a little hanging over the hole I made. That done I mixed up a small batch of epoxy and secured the tape wrapped servo in place.
When the glue was dry I simply attached the wing to the fuselage with the three supplied bolts through pre-drilled holes in the wing into pre-mounted nuts in the wing saddle area of the fuselage. (A perfect fit, how sweet that is!) With the servo properly in place the wing was done.
Four intake holes were drilled and ground out of the nosecone to allow air to enter to cool the motor, speed controller and battery. The space for these air intake holes came molded into the nosecone. I applied masking tape to the area and drilled an initial hole in the center of the desired space with a 1/16" size drill bit. The tape kept the drill bit from slipping when I started my hole. I repeated the process in the other three molded air intake positions and then moved up with progressively larger drill bits expanding the four holes. I stopped after using the 1/4" drill bit. Next I used my Dremel like drill with a dome shaped grinding stone to enlarge the holes to the size I desired. A rounded file could have been used for this last step if I didn't have the Dremel tool. With the intake holes finished I repeated the process making four exit holes for the air in the fuselage behind the wing mount area. Again the spaces for these venting holes was molded into the fuselage. It was necessary to make the exit holes longer and thus larger than the intake holes so that they would properly draw out the air. The exit holes should be double the volume of the intake holes to properly do their job. My way may seem a little lengthy and you could start with a larger drill bit but my way worked well for me and was really very quick.
The next step was mounting the motor into the nosecone. This was a simple process of measuring and drilling the two mounting holes into the motor mount on the front of the nosecone. My friend Jeff Hunter is spot on in doing this so he did the honors for me on this plane. Once again his two holes were perfectly placed.
The vertical fin is molded into the fuselage and as discussed at the start of the assembly, the horizontal stab simply needs to be glued into place. For this I measured and determined the exact location for the center of horizontal stab and then marked the stab and roughed up the finish on it to give a surface for the glue to grab onto when I glued it into the fuselage. The elevator came pre-installed on the stab but I needed to glue the control horn into the elevator. I determined gluing in the control horn would be the next to last step in mounting the elevator servo and connecting the linkage.
The elevator servo mounts in the tail and was simply glued to the side of the fuselage. Before glueing the servo in place it was necessary to make sure the selected servo fit and its servo arm worked properly in the molded space for the servo arm and control rod in the tail. The Hitec 56 servo came with several servo arms, two in a bag and one on the servo. The one on the servo had four arms at 90 degrees from each other. Since it looked like one of those arms would work I cut three of the arms off and mounted the control arm going out and centered over the right side of the servo. I wrapped the servo in one layer of masking tape and I added a 12 inch servo extension wire (taping the connection together) so that it could reach to the receiver that would be mounted forward in the fuselage and trial fitted the servo inside the fuselage. The servo arm appeared to be too long to fit into the molded slot and have the servo flat to the inside of the tail fin. I removed the servo from the fuselage and trimmed the servo arm by removing the outer of the two holes in the arm. I trial fitted the servo again and it worked smoothly in place. Trial holding the servo in place I operated it and the servo arm seemed to fit and work fine. The fuselage has a molded channel for the servo arm and the control wire that gives the space needed.
The elevator control horn came already fitted onto a control wire that had a sideways Z-bend to fit onto the servo arm. I inserted this wire into the fuselage through the exit hole just in front and below the elevator. I took the servo arm off of the servo and fit the Z-bend into the servo arm. I put the servo arm back on the servo and started to practice fit the servo in the back of the fuselage.
PROBLEM: I couldn't get the control rod wire back far enough to fit the elevator horn into its slot. I pushed the servo back but the wire was still too short. I determined that the wire that came with the plane was about 5/16" shorter than I needed to have with my Hitec 56 servo located where (because of its size) I needed it to line up. (This location appeared to be designed for the servo arm to fit perfectly in the molded channel.) I disassembled my servo trial fit and made my own control rod with a piece of music wire approximately the same diameter as the wire that came with the kit. Using the original wire for a guide I made the new rod 5/16ths of an inch longer between the first inside bends at each end and trial fitted this with the servo in the fuselage. The servo fit where I wanted it to and the elevator control arm fit were it needed to fit into the elevator. I connected the servo to the receiver and made sure the servo arm was properly centered. Using thin CA I glued the control horn into the elevator and the servo into the fuselage. After testing the electronics and making sure everything worked properly I glued the servo more securely with some epoxy. After that was dry and the elevator was tested I secured the servo cover in place with a very small amount of thin CA.
By wrapping the servo in masking tape, if it later needs to be replaced I can cut the masking tape on the left side of the servo and peel it off and remove the servo. The molded covering for the servo hole can be removed by spraying a debonding agent on the very small amount of CA used to secure it in place. While I hope to never have to service this servo in the fuselage it remains something that can be done albeit with a little difficulty.)
As described above, both servos were now in place. In the nosecone from front to back I had the motor and then the speed controller followed by my Hitec 555 receiver and then the Lipoly battery pack. This had the receiver right in the middle of the opening in the top center of the nosecone and made plugging in the servos easy to do. The battery and receiver were secured in place with Velcro. I ran the antenna out one of the rear air cooling holes and lightly taped it once at the back of the fuselage and much of the antenna hangs free at the back of the plane. There is a small piece of tape facing tape in the center of the tape that holds the antenna in place so that the tape sticks to the fuselage but not to the antenna itself. (The antenna wire has to be loose and able to move as it is pulled forward when the nosecone comes out of the plane.)
The plane could be assembled in a night but I broke up my construction to get Jeff Hunter's help mounting my motor. I trial fitted everything before I glued the servos in place and was thrown off briefly when the Hitec 56 didn't fit in the molded space for the aileron servo and when the elevator control rod didn't fit my installation. But aside from those two points everything else was smooth sailing. I didn't add the velcro for the battery until after I had found where to place it and balance the plane without adding any weight. The assembly was really very easy but I would have still liked some instructions and recommendations for what servos to use etc. I like the confidence that instructions/recommendations can give you.
Soar USA posts that the plane's weight RTF starts at 16 ounces. Mine was 20 ounces or 25% over the weight of the declared starting weight. But I didn't know what motor, battery or servos were supposed to be used to make that announced weight of 16 ounces. I was not at all unhappy about the planes weight but the proof will be in the flying.
My battery wires and wires from the speed controller were longer than they needed to be and took up the extra room that might have been available in the nosecone. I shorten them and that allowed air to more easily flow through the nosecone. I had sufficient wire from both servos to leave them connected when I pulled the nosecone forward to plug-in or unplug the battery from the speed controller or to remove the battery to recharge it. All and all a very nice nice set-up. I was delighted with how perfectly positioned the wing mounts in the fuselage were for the wing and the mount for the nosecone securing bolt was also perfect. While this is something I have come to expect in Soaring USA products I wish every plane could fit as perfectly as my Sunracer.
I am using my Jr XP 9303 transmitter. My Sunracer has its own memory slot in the transmitter as the transmitter has 30 memory slots. Unless you are absolutely spot on when you install your servos you will want a computerized transmitter or you will need to use your trim tabs to center your controls as the control linkages have no mechanic adjustment. For my elevator I was spot on and no adjustment was needed by trim tab or computerized subtrim. For my ailerons and snap in linkage I placed the servo arm slightly off center and than needed about eight clicks of left subtrim to square up both aileron control surfaces. I prefer using subtrim and memory in my computer so that I know the plane is always set when I go to the plane's program on my transmitter. It also gives me complete use of my trim tabs if I need them while flying the plane. (If I do adjust the trim tabs my transmitter will remember that as well for the next time I use the program.)
If you fly at full throttle all the time you will find you have to constantly turn, climb or dive. Obviously this is a special purpose plane (F5D pylon) and the majority of those who fly it will be going for maximum speed and making pylon racing turns the majority of time they are flying it. In Arizona a couple young pylon pilots couldn't believe how I was flying my Sunracer and mumbled under their breaths: "What a waste." But even they were impressed when I doubled my speed for a few hot laps. They were then disappointed when I throttled back again. While it really shouldn't be flown too slowly, I found it a fun plane to just fly at 30-50 miles per hour with just a few short bursts of maximum power for an unlimited climb followed by a high speed pass or two. That's sufficient fun for my taste, my vision...and initially, for my knees.
The plane goes where I point it! No wobble, no flutter. With full throttle it goes vertical. Dive 800 feet and it pulls out easy as good be. It is designed to fly and glide fast. Don't try to go too slowly when gliding and control remains no problem. It handles so smoothly I am confident that the plane can easily handle more speed than my 100 miles an hour or so. I have become very confident when flying it as it has shown no bad habits. Also I can follow it visually about 50% further than I could my previous 27" speed 400 pylon racer.
All flights start with a handtoss and less than 50% power was sufficient to climb smoothly. Full power starts are possible and dramatic but really not how I like to start the flight. All landings are sliding skidding stops and the plane has no landing aids. Try and pick a nice flat area with some nice short grass to land on and set up for your landings with a smooth level approach. This plane literally took me twice the distance but half the time on approach as I thought it would. My distant final turn is half as high as my "fast gliders" and I am still going fast when I touch down. This is not hard to do when landing in wide open spaces but a small field would be murder. This is not a park flier!
At full speed you can make a lot of left turns. You can climb and dive at will. For many of you "all out" will be your desired means of flying. Since I do most of my flying on partial throttle and some with the motor off, I can do unlimited axial rolls and perform S turns. However, lacking a rudder it can't do many acrobatics. For what it can do and what it was designed to do my plane handles beautifully. Axial rolls, S-turns, sharp banked turns, great dives and climbs. It can even thermal if you hit a strong pocket but it doesn't show a thermal as there is minimal reaction, if any, flying through a bubble of lift. It can also be flown at the slope for days with little wind or on and off breezes.
NO! Don't even think about flying a plane like this until you and others consider you an advanced pilot or expert. While assembly is very easy as described above, this plane is simply too fast for a beginner or intermediate pilot to be flying.
I found video taping the Sunracer to easily be the greatest challenge of this review. Some of my friends tried to videotape several of my flights and had no success. I mean no success! I tried to videotape Jeff Hunter flying my Sunracer and I had two problems. First, there were no clouds in the sky to help give a reference point to show how fast it was flying. Second, I couldn't keep the camera on the plane at full throttle. Despite my repeated efforts no full, high speed passes were caught on tape. However some passes of moderate speed and glide were caught and those make up my videos.
Fortunately, RC Group member, The Tick, was more successful in catching his Sunracer flying high speed laps and he has shared his video with RC Groups in a discussion posting. The Tick has a different motor set-up but you can get a better idea of possible performance from his video than mine. Sorry, I only had access to a Broadband version. Thanks Tick for sharing and allowing me to use your video in this review.
The Sunracer is a beautiful kit and could go together for an experienced builder/assembler in one long evening/night. I am told it can do sustained level flight at 170 mph and I believe it. My top speed in level flight was about 100 mph and there was no flutter. The first time that speed was enough to give me an adrenalin rush that made my day and if truth be known, made me a little weak in the knees the first couple of flights. (Yeah I'm a wimp.) This plane completely satisfied my need for speed as I have outfitted it. My Kontronik's motor and controller continue to work flawlessly as does my Apogee battery pack. They work so well together they didn't get much attention in this review. With my on/off throttle flying and mixture of low and high speed operation my flights have been about ten minutes and there was no problem of over heating for the motor or battery pack. In fact my Apogee battery pack has gone down from a reading of 12.60 volts to a low of 11.38 volts so with my flying style I could easily stay up for twice as long as I have been and still have a large margin before I would get down to 9-volts. At the start I highly recommend the Kontronik combo and the Apogee battery pack. The Hitec HS-56NB has handled the stress of pulling out of an 800 foot dive and keeps working without a problem. The controls respond smoothly and precisely. I remain delighted with this plane and the way it handles and flies. As the saying goes: "It flies like it is on rails."
The only difficult thing about flying the Sunracer is keeping it in sight and that is a lot better than I initially thought it would be. In good sky, clear or with some white clouds, I really have had no trouble keeping track of the Sunracer. I have noticed that since flying the Sunracer my brushless powered WWII fighters are now not at all intimating to fly. My comfort level with speed has moved up across the board.
PS: This was not an assigned review for RC Groups. I bought the plane at the AMA show and thought it was so pretty and so nice I wanted to share it. To all you pylon racers, I envy your nerves but even more I envy your eyesight on gray sky days. Finally, I love my Sunracer just the way it is...but maybe Kontronik has an even hotter set-up they would like reviewed in my great little Sunracer...This speed thing is a bit addicting.
|Jun 06, 2006, 03:57 PM|
Apogee Batteries available from PFMDistribution.
For any of you who don't know, Apogee Batteries are available on the Internet at: www.pfmdistribution.com Bill is an avid hobbiest who sells a great product. Check them out. Michael Heer
|Jun 16, 2006, 03:01 AM|
Seems nice sports combo if you are not going to race
One advantage of a non commisioned make a combo for my own personal needs is that there is no need to over prove the set up and if it works for you well a thats all that realy matters and folows my method I buy for me and my limited funds and that all I realy care about
With that class of plane you should hit 130mph plus in the deep vertical dives for a few seconds motor off and it should go down the runway at 120 mph or there abouts for a few seconds as it slows down to 100mph power up then climb and repeat
Much cheaper solution than super hot motor and flying tiomes should easly exceed 3 minutes probably 6 to 10 minutes with climb speeds at 70 mph and dive speeds exceeding 100mph
My experience with s400 class vooddo in that mode of flying deeeeeep high speed vertical dive flying style with two hs55 servos for the wing was that wing servos burnt out after some few high speed vertical dives and so replaced with c161 then c171 and now looking to go digital with single servo
For that class of F5d craft I would only now consider to use a high class digital servo of the sub micro hs55 size or 2 hs81 micro sized servo or better similar types for aerlions or mayby single hs81 type with
Other than that the combo looks very good and would suffice if you were to fly relitivly level at around the 110 mph mark and avoid ultra fast high speed dives but thats not easy as its so easy peazy to drift into steeper faster dives
Keeping the power output drain at these levels make the LiPo with its lowwer weight but lowwer ability to deliver amps (in this time but the future is coming fast ) work well and not be silly high costs for sports flying
this means that if newwer generation lipos arrive for same weight with more capasity and more c rates that swapping motor for kontronik fai fun 55 s480 will be able to give near f5D performace
Not that you would need to know as your preety informed but for other considering this or similar craft the forces on the airlions can vary a lot as the doubling of speed means quadrupling of the forces on the craft and control sufaces and if servos are close to thier limits the servo motors can heat up from this extra work and burn out usualy on a nice hot summers day
So far I been lucky no in flight burn outs but my new rule exceeding 130 mph its digital servos for the wings and if funds or design space allow digital for the elevator but must admit after many hundred high speed dives never seem to have had a inflight elevator issue occor until last week where my super hotted up Voodoo with winds of 35 mph following in high speed vertical dives with folowing wind Voodoo went AWOL and crashed into a forest verticaly doing mayby 160mph plus
As the voodoo didnt have two wing servos I wasnt able to use my delta mix in flight phase mode with mc 24 to try overide appearntly jammed elevator servo (option my sports F5D all have ) as it went sailing off down wind out of control
After several days searching forest still searching for beast in the thick forest
using digi camera on the end of 4 metre pole with 5 metre usb connector to laptop mostly to verify that elevator c171 servo had in flight failure and it wasnt pilot error
presently out tree hogged by forest
So if you go down to the woods today beware a Voodoo lurks there waiting to..
|Jun 30, 2006, 02:11 AM|
Nice review Mike.
FWIW, I set up my tail servo (JR DS281) on the shortest servo arm I could, and then drilled a new hole as close in as I could without the Zbend hitting the spline section of the arm. This way it easily fits in the molding and I still get enough travel on the elevator.
|Feb 28, 2007, 11:41 PM|
To Speed Freak:
You can buy the aircraft from SoaringUSA and contact them for a motor set-up. You can easily go over 150 MPH with this plane with the proper set-up. I'm happy flying a nice slow 100 MPH Mike
PS: If you really want speed get the right plane and do dynamic soaring on the back side of the slope hill where they are hitting over 300 MPH. But they don't use a motor as it would slow them down.
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