|Wing Area:||625 sq. in.|
|Wing Loading:||15.67 oz/sq. ft.|
|Servos:||2-Hitc HS-55 and 2 Hitec HS-322|
|Receiver:||Hitec Electron 6|
|Battery:||Kokam 3 cell 3200 lithium polymer|
|ESC:||Jeti Advance 40 Plus|
|Manufacturer:||Green R/C Model Airplane Co.,ltd.|
The Full scale Super Dimona is a two-seated powered glider made of fiber-reinforced high-tech composite construction. Equipped with Rotax engines with 80, 100 and 115 hp (=turbo-charged variant), the Super Dimona is perfect for glider pilot training and glider towing. http://www.diamond-air.at/en/products/HK36/index.htm
Until recently I have always had a place in my plane stable for a glider. I taught myself to fly R/C using a Great Planes Spirit 2 meter glider and progressed from there. My last powered "glider" was a Sirius f5b racer. I had moved away from gliders into the world of electric sport models all the while thinking of getting back into gliders to some extent. When I saw the Super Dimona I immediately thought this plane would combine the best of both worlds for me, the flight characteristics of a glider in an electric sport airplane package.
The contents of the kit box included:
Accessories required -- provided by Hobby-Lobby for this review:
The first thing I always do before assembling a model is read the instruction manual -- twice. The manual for the Dimona is not always clear. There are also some improvements and upgrades to the kit that are not reflected in the manual. Overall, the manual is a decent guide to assembly but it could be better.
The front landing gear is constructed first. Note that the front wheel pant has a small piece of hardwood fiber glassed to the inside of it.
At this point the instruction manual recommends adding the small gear retaining plate that secures the wheel pant. Don't do it yet -- I did because I was following the instructions.
"Why stop here?" you ask? The manual has a picture that shows the wire gear coming straight up off of the pant, if followed this will provide a pant that will be severely dragging on the ground. The problem for me could have been one of two things. Either the gear was not bent to the proper angle or the gear hole in my fuse was not drilled straight. Either way you will want to wait until you mount the gear to the fuse before adding the retaining plate so that you can get the proper wheel pant angle.
After the gear set has been assembled they can be mounted to the airframe. The front gear is passed through a small hole in the bottom of the fuselage and up through a hardwood gear block inside of the fuselage. The front gear is held in place with a set of wheel collars on the inside and outside of the fuselage. The steering control horn is then slid onto the wire gear and secured with a small set screw. Since I followed the instruction and secured the wheel pant earlier without checking the pant angle, my wheel pant would be severely dragging. I had to remove the front gear and bend the wire to allow the pant to be parallel to the ground. I felt this would be the best solution at the moment because I didn’t want an extra set of unsightly holes in my front wheel pant.
The main landing gear are inserted into two small slots on the bottom of the fuselage and secured in place with screws. My first attempt at mounting the main gear did not work. The inside ends of the aluminum gear were too long. It kept the holes in the gear from lining up with the mounting holes in the fuselage. I had to sand the ends of the gear so they could be pushed farther into the fuse to line up with the mounting holes. After the gear were sanded they mounted perfectly.
The wing build was quite straightforward, as shown in the photos below.
A big surprise here is that the holes for the control horn screws come pre-drilled in the ailerons! NICE! The horn plates lined up to the screws on the first try! Probably a first for me.
The hinges provided in the kit got a little stiffer than other ca hinged that I have used. They needed to be exercised a bit to ensure fluid movement.
This is definitely the least amount of time I have ever spent securing tail surfaces on a plane! The attachment of the horizontal stab and elevator could not be easier. The elevator comes pre-installed on the stab and the whole assembly is attached to the top of the fin with two screws!
Be sure to mount the elevator control horn before attaching the stab.
One note of caution: On my kit the Z-bend extension was just barely inserted into the end of the elevator pushrod. I am fairly sure if I didn’t catch this it could have posed a serious problem.
At this point the manual recommends installing a wood motor mount into the front of the fuselage. My kit came with the mount already installed.
A nice touch on this model is the countersunk holes for mounting the motor.
After mounting the motor I noticed that the motor had up thrust and left thrust. Since the manual did not note that this should be the case and I have yet to run across a model that calls for these conditions, I checked with HL. They confirmed the model should be between 0-2 degrees right and 0-2 degrees down, so I had to change the motor alignment. I simply shimmed the motor with washers to set the thrust angles to match the front of the fuselage with the spinner installed on the motor. (HL has checked their stock and not heard of another model with this thrust issue, but check your model to be sure!)
Although the manual recommends installing the battery tray before the servos and radio system, I chose to skip that step in order to be able to move the battery for c.g. purposes if needed.
(Note: The manual shows the servos mounted perpendicular to the fuselage although as provided the servo tray will only let you mount the servos parallel to the fuse.)
The kit comes with the servo tray, pushrods, and pushrod clevises already installed.
Again, wing mounting was straightforward and simple.
Up until this point I had not fully realized how large the wing span was. With the wings installed it wasn’t easy to move around in my cramped workspace.
Although the kit comes with a receiver mounting tray, I decided to skip the tray altogether and mount my receiver to the rear of the cockpit opening with Velcro. Since the motor and controller are mounted up front, I wanted to get my receiver as far away from them as possible to avoid interference.
The desired CG was 60mm behind the leading edge at wing root. With the battery temporarily installed in the now lowered location (see photos above), I could see that I was a bit tail heavy. Normally I would just move the battery up to adjust the C.G., but the nose gear block was in the way. I moved the battery up as far as I could, then installed a small strip of lead to compensate for the tail heavy condition.
The canopy consists of two pieces, a clear canopy and a grey cockpit floor. The manual recommends to either “fix the cockpit and canopy together on the fuselage with adhesive tape or 4 pieces of 2x8mm screws". I chose to do a mix of the two. I didn’t want to attach the final assembly to the fuse with a bunch of screws or tape like recommended. The completed assembly is very solid and is easily installed and removed from the fuselage for quick access to the battery.
At this point there was little left to do...I reattached the wings and rechecked the balance in preparation for the maiden flight. But before the maiden, I ran the power setup on my trusty E-METER to see what kind of power I was producing. At full throttle the power system produces 354 watts at 32.5 amps. I felt that the Dimona would have fairly spirited flight with about 84 watts per pound.
I had been waiting almost five months since the airframe was completed to fly it. Winters and spring in central Ohio do not give way to too many good flying days. Five months was enough! Finally...the day of the maiden had arrived. I was ready to fly.
This was the best available day yet for me to fly. Unfortunately by the time I arrived at the field and assembled the Dimona the wind was gusting to about 15 mph across the runway. I did my usual preflight ritual consisting of checking the control throws and doing a range check (I carry a separate flight battery for these steps. I don’t use the flight battery and controller BEC because I don’t want to plane to surge if it gets hit with interference).
After it passed the range check I plugged in the flight battery and waited for the now familiar speed controller beeps. I was slightly nervous about the cross wind but felt the Dimona could handle it. I walked the Dimona out to the tarmac and set it down. Almost immediately the Dimona began to slightly weathervane. With its light wing loading and strong power combo, I felt that Dimona wouldn’t need much runway to get airborne so I angled it into the wind and prepared for takeoff. I slowly advanced the throttle and the Dimona surged ahead. After I was comfortable with its ground handling in the wind, I advanced the throttle to half. The Dimona Quickly jumped into the air.
Once airborne I went to full throttle to get away from the buffeting air near the ground. The Dimona climbed out much steeper than I would have thought. The wind was helping. The Dimona was being bumped around pretty good, so it was a bit hard to tell how much trim it needed. It did need a bit of down trim but the ailerons and rudder were a bit hard to figure out. The speed of the wind was slowly increasing, making trimming even harder.
I was impressed with how well the Dimona handled the wind but I quickly realized that it would be hard to give this airframe a proper evaluation in these conditions. I do think that an airframe's ability to handle wind well should be evaluated -- just not on a first flight before a C.G. evaluation and the control surfaces are properly trimmed!
So, I decided to land. I flew the Dimona to the end of the field and prepared for landing. I chopped the throttle to about a quarter. The Dimona was slowly making headway which was perfect in these conditions. Once over the tarmac I pulled the throttle back to idle. At first it just hung there in the air slowly advancing. Finally it began to settle in and I set it down on the runway for what appeared to be a perfect landing... until it took off again about five feet later. I slowly advanced the throttle to keep it from stalling and set it on the runway again. This time I applied some down elevator to keep it from getting airborne again. It rolled out about 20 feet and came to a stop. I quickly picked up the Dimona and took it back to the pits. Even though this was not a completely successful first flight I was impressed with the overall power and how well the Dimona handled the wind. I felt the Dimona deserved a better day for a test flight so I packed it up and headed home, waiting for a better day in Central Ohio.
The day of the second flight started out with a hard rain, which left as fast as it appeared. The wind was now perfectly calm so I packed up the Dimona and headed to the field. I quickly assembled the Dimona, performed a range check, and then taxied out to the runway. I slowly advanced the throttle to about the halfway point and headed briskly down the runway. The Dimona tracked extremely well. The only thing diminishing the perfect takeoff experience was the extremely noisy landing gear. I slowly advanced to full throttle and lifted off of the runway.
The climb out on the Dimona is very steep under full power. I made a shallow turn at the end of the field and began to climb to two mistakes high. During the first flight, I had trimmed out the elevator but never had a chance to trim the ailerons or rudder due to the buffeting wind. The Dimona needed no aileron or rudder trim. In my more than 12 years of building and flying experience I have probably only had 10 or so planes that needed absolutely no aileron trim (more than 60 planes at last count). After reaching my two mistakes high altitude, I began to put the Dimona to the test.
I wanted to test the stall characteristics first. I slowed the Dimona down to a crawl and slowly fed in more up elevator. The Dimona began to porpoise slightly at first then stalled straight ahead. The nose dropped a little quicker than I would have liked for a powered glider but I realize that of course the Dimona has a higher wing loading than most non-powered gliders. The recovery from stall is very easy and happens rather quickly. I just fed in a little power and pulled back on the elevator slowly.
Next, I did some lazy slow figure eights to get a feel for its transition in turns during slow flight. One thing was a little surprising. The Dimona has a tendency to drop the nose in turns a little quicker than I was expecting during slower flight. It is easily corrected by coordinating the turns with a little opposite rudder. During higher speed flight the nose dropping tendency is gone. I was making a downwind turn when it started to drizzle. I wanted to test the higher speed characteristics before the heavy rains came, so I applied full throttle. Under full power the Dimona tracks and turns extremely well. It does have a slight tendency to climb under full power, however. During the first flight in the higher winds I noticed the wing slightly bouncing while being buffeted. (Hobby Lobby indicates that at 0/0 thrust angle, the model doesn't have any change in elevator trim at different speeds although I noted a slight climb under full power.)
I wanted to try an easy loop but was a little bit weary after seeing this. I decided to give it a go. What’s a test flight without a loop? I backed the throttle down to half and slowly fed in some up elevator. The Dimona climbed over the top and completed a perfect loop with ease. I did notice the wing slightly moving, but nothing that caused me any concern.
I wanted to try a roll but when I fed in high rate aileron the Dimona didn’t seems to respond quick enough so I backed out before it went over on its side. I decided to wait on the roll for another flight when I can dial in higher rate aileron.
At this point the drizzle was turning into as light rain so I decided to bring the Dimona in. I set up for landing and slowly pulled the throttle back. The Dimona settled in perfect in preparation for touch down. I began to slowly feed in a little elevator for landing but the Dimona began to climb again. The elevator is very effective even at slower speeds. I released a little of the elevator, added a little throttle and set the Dimona down on the runway.
Up until this point, due to weather issues, I had not had a chance to get a good indication of how well the Dimona would glide or thermal. Flight number three would be a bit of a surprise. It was 83 degrees and fairly calm. I arrived at the field and did the usual flight preparation. I taxied the Dimona out on the runway and slowly applied throttle until I was at about 50%. Once airborne I pushed the throttle all the way to full. The Dimona climbed out like a homesick angel. After a 20 second climb out I cut the power to the motor. The Dimona settled into a nice slow glide. I was impressed with how well it flew in these conditions. I was expecting a steeper glide rate because of the extra weight of the power system. As long as it was kept in nice shallow turns the Dimona responded to control inputs well (During slow speed glide I switched over to high rate aileron for more control). If the turns were a little sharp the Dimona would drop the nose and pick up speed quickly.
The initial 20 second climb out resulted in a 3 minute glide. My longest glide on this day was a 4minute 20 second glide after a 15 second full throttle climb out. How relaxing (I flew my f-20 electric ducted fan before this). I was hoping to catch a thermal to see how long I could keep the Dimona in the air before applying power but the slight breeze was pushing the warmer air over the local interstate. After seeing how well the Dimona was able to glide I have no doubts that it would perform well in average and above thermals. I spent the next 19 minutes doing lazy figure eights in the sky. I wasn’t sure how much battery was left so I decided to land (After recharging the battery later I found that I had used 1946 mah out of the 3200 mah battery). I set the Dimona up over the runway and cut the power. I set the Dimona down on the runway and it bounced a little before settling on the tarmac. While taxiing back to the pits I noticed that the steering was now out of trim. Once I came to a stop I pulled off the canopy and saw the problem. The front gear block had come loose. The landing had a bit of a bounce to it but nothing that I felt should knock the block loose (I later fixed this by gluing the block back in place and reinforcing it with carbon fiber strips. The repair took about 5 minutes). After the flight a couple of fellow flyers at the field were commenting on how well it flew. One flyer summed it up perfectly saying “That Dimona flies great and looks majestic in the air”. I agree.
The full scale Super Dimona is billed as being perfect for glider pilot training. The model of the Super Dimona easily fits that bill. This model is well behaved on the ground and in the air. It presents itself as a great combination of a powered sport/scale plane and glider in one package. Obviously there will be some limitations if one is looking for an airframe that is matched perfectly to each discipline but the Dimona crosses that gap without giving up too much either way. It is the perfect plane for those lazy days at the field when you want to enjoy yourself and not have to over think your next step while flying.
All of the components supplied for this review have performed flawlessly. The motor hauls this plane around suprisingly well considering its size, or lack thereof. The CellPro battery maintains its voltage well under load and has been improving slightly with cycling (Although the plane has three flights on it at this point, the battery has 7 charge / discharge cycles on it). This is one occasion where the recommended accesories and power system are perfect for this airframe.
Look for updates to this review as more flights take place.
|Jul 13, 2006, 06:35 AM|
Thanks so much for your review. I looked at this model for a long time before I bought it. I got the parts from HL, the model came from Green Models.
I am now more anxious than ever to get mine together and in the air.
I think I have all the parts, I may even print out your whole article so that I don't make any errors in assembly. I do have a friend who will help when needed.
Again thanks so much for this review.
|Jul 14, 2006, 09:23 PM|
The one thing I would have you do before assembling the model is to secure the front gear block better before you start adding anything else in the fuse. This is a weak point on this model. I added strips of carbon tow after flight 3 and have not had any problems since (2 more flights now).
You will enjoy this model. its a nice easy flyer. good power with the recommended setup. If you have any questions post to this thread or shoot me an email.
|Jul 15, 2006, 11:27 AM|
I'm finishing one as we speak. I ran into the problems you did. 1st flight is Sunday morning.
|Jul 15, 2006, 02:19 PM|
bob..what are you doing with a dimona..no fan on this you know.
Funny you responded when you did...I was working on my bobecat this morning..the one i bought from you two years ago....
good luck on the maiden!
|Jul 16, 2006, 11:31 PM|
Flew great. Need to add some more nose weight. Also going tp add a separate nose steering servo. So I can slow it down but not affect the rudder throw.
|Jul 17, 2006, 04:49 PM|
Joined Feb 2002
I mostly fly sailplanes, but now that I am busier some times I don’t have time to get the winch out and set it up. So I bought this plane mainly for the span and soaring potential.
Does it thermal? The answer is YES, and considering the weigh and extra drag from gear and prop, it glides well. This plane won’t core nor will clime like a competition glider but, it will do the job. It is also harder to read lift with this plane, but that is understanding, those might sound like short comings but they are not, it is less forgiving on glide, so I consider it “weight training” for soaring. As a sailplane it will benefit more by using the left stick, or coordinated turns, which suits me just fine. The nose will drop quickly on slow tight turns, but once you find the threshold then is Ok. (Just don’t do this exorcise at low altitude.)
It doesn’t take off from grass very well (not a power issue, but the front gear will go out of alignment); in fact you’ll need a pave runway. I found a nice parking lot where I can take off and land, and it doesn’t require much room.
It will do all the standard acrobatics, loops, rolls, hammerheads with out any problems, but excessive speed would probably crack the wings. In another words I would not put it into a massive dive at full throttle and then go for a snap roll, that wouldn’t be fair.
The fuse is all glass and gel-cote exterior, very nice and light, but it could crack if it isn’t handle with care, in another words don’t drop it, squeeze it too hard.
Mine came with upward thrust also, but very easy to remove.
I need to come up with a better latching system for my canopy, it keeps falling off. Again, that is my problem.
What I just said might sound redundant, since Mr. Petrilla did such a nice job reviewing this plane; I just wanted to share my impressions
Thank you, I enjoyed rending it
|Jul 18, 2006, 08:40 AM|
jeb..good post. Its always nice to see that fellow flyers have the same experiences i do with a review aircraft.
Funny you mentioned the gear going out of alignment...I had another flight on sunday. The landing was actually fairly soft and the front nose gear flipped completely around and scuffed up the front wheel pant (pavement). I figured the front set screw on the gear leg had come loose but when i went to loosen it to reset the gear i could hardly move it because it was so tight. I added some thread lock between the control horn and the gear leg..hope this helps.
Since my review published I have tried a roll with the Dimona. I saw some flex in the wings when upside down that i didnt particularly care for...nothing dramatic but i dont need to do it again.
how is your canopy attached....try my system..no problems yet.
|Jul 18, 2006, 12:15 PM|
Ok, now those of you who have put together your dimona, what size of carbon fiber did you use to beef up the nose gear area?
Also is there any way to move the battery farther foreward so you don't have to add weight in the nose, or am I just hoping for the impossible?
Platte Lake MI
|Jul 19, 2006, 08:46 PM|
what size carbon fiber did you use? Also where in Ohio do you live?
I moved to MI from Cincinnati, used to live in Wyoming, but now I am just 35 feet from a lake.
Platte Lake MI
|Jul 19, 2006, 09:27 PM|
Joined Feb 2002
|Jul 20, 2006, 08:10 AM|
i used 1/4 inch carbon tow. i ran the strips across the top of the block and down and across the bottom of the fuse.
as provived, there is no good way to get the battery up into the nose around the gear block.
I am in columbus...........
|Aug 20, 2006, 10:10 AM|
USA, MO, O'Fallon
Joined Dec 2003
Has anybody got any bright ideas for a folding prop for this plane? It might not help much because of the wheels, but it might improve the glide characteristics a little bit.
HL is currently out of stock (9/8/06 is the expected date) and so my second one lives on in my dreams (lost the first to some odd interference shortly after take-off - the short version is that the airframe does not like nosing in from 25 feet).
|Aug 21, 2006, 10:55 AM|
Ok, now for the really dumb question. What is 1/4 inch carbon tow? I am not aquainted with carbon fiber stuff, so I don't know what tow is. I am new to building with the new space age materials. I used to use Elmer's and gaugze for strength when I was flying control line planes years ago. So after coming back 40 plus years later, I have a lot to learn.
Has anyone tried ordering from Green Models directicly. I got mine very quick from them. It came Fed Ex and I have bought two Butterfly's from them and they are very nice to deal with. I got my Super Dimona right from Green Models, I got the rest of the parts from HL.
Green Models link:http://www.greenmodelusa.com/aboutus.html
Platte Lake, MI
|Aug 21, 2006, 12:40 PM|
carbon fiber tow is also called carbon tape (without the hot melt glue to iron it on first before you add ca)... here is what hobby lobby sells. http://www.hobby-lobby.com/carbonfiber.htm
CCF001 1/4 x 48" Iron-On CF Tape ..... $ 3.50
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