Sukhoi 37% Krill Model


For the season 2011, I have the inmense pleasure to be part of Team Krill

The model chosen was the most recent design by Sebastiano Silvestri, the Sukhoi 29, 37% in its second version (version 2011) which incorporates new “mega-ailerons” to be controlled by three servos per aileron, as well as a new rudder which gets wider at the tip, like in F3A, to improve precision, slow down downlines and increase the power of the rudder (as well as being a really cool place to put stickers!)

I wanted for the colour scheme to be something a little different, I loved the “Razor” scheme, but wanted mine to be unique. After playing with colours, I decided to change the dark gray for black fading into dark blue, as well as some shaded areas. The underside was to be a very simple blue and white set of squares to assure great visibility in the air.

When it arrived, the first thing that I noticed was the finish, it was perfect, and truly amazing. Both the finish and the great colurs made it really stand out, just what I wanted.

When deciding the equipment to use, I decided to put it together as my dream plane, using all what I considered to be the best, this being:

-DA 170
-Exhausts: RE-3 by MTW-Silencer

Electronics: Powerbox-Systems:
-Powerbox Royal RRS
-Lipos 4.000mAh
-Spark Switch
-Smoke Pump
-Powerbox-Systems Double servo connectors
-Powerbox-Systems adapter cable Futaba-Multiplex

Servos: JR 8911. x3 per wing, x2 per elevator and x3 on rudder
Radio: FASST by Fuataba

Revoc custom wingbags

The building process was not complicated, despite me taking a little longer than usual due to being extra carefull to get the perfect finish just as I wanted it, finding the simplest but also safest and cleanest solutions possible.

Starting with the wings and elevators, as with any model there is not much that needs to be done, simply gluing in the control horns, prepare the required extension leads, screw in the servos and hook up the control linkages..

Fortunately, to simplify the above Krill already drill the holes for the control horns for you, so this is something less for you to do.

All the servos are “hidden” inside the wings and elevators. The elevator servos are installed through holes in each side of the stabs, where as the wings have a hinged access which hides the ribs to which we screw the servos. Once installed, we simply tape the access clodes, thus keeping an invisible access to the servos.

For all the connections in the plane I decided to install the Powerbox-Systems extensions/connectors, as these use a Multiplex conector (which gives better security) along with a moulded plastic around the connector (assuring that no connections can be pulled off or broken) and also connecting two servos with just one connnector.

*Click here to see more information about the Powerbox-Systems Multiplex double connectors.

With the wings finished, we start with the fuselage. The first thing that stands out is the height of the fuselage is amazing, this will be great for knife edge, as well as giving us loads of space to install our equipment wherever we want without any kind of problem.

I started with the engine and exhaust system. The DA170 is very easy to install, just having to make the 4 holes needed and use the spacers sold by Krill for this engine. As I prefer not to bolt the engine straight to the stand offs, I put a plywood plate in between, as this gives the engine a better, flat surface to bolt to.

Installing the RE3 tuned pipes by MTW-Silencer are just as simple as any usual exhaust system, with the only difference being their lenght. In order to get them to fit in the model I had to remove the pre-installed rudder servo mount. Fortunately I did not intend to use them anyway, and I could simply cut it out, as it is only glued to the formers and not actually to the fuselage. It took time, but I was able to get it out without damaging any of the fuselage or formers.

To avoid that the exhausts could turn inside the model, I add a screw to the teflon which avoids them being able to go backwards either.

*Click here for the full article about the DA170 and the RE3 tuned pipes by MTW-Silencer

For the smoke connections on the headers, to assure that the smoke lines could not slip off the nipples, I soldered an extra piece of brass tubing to the end of the nipple, thus giving a better grip for the smoke line, especially once held on with a cable tie.

Now all we are left with are the electronics. This model was no more complicated than any other, however I wanted such a perfect electrical installation that I spent longer looking and thinking than actually building! The idea was to see as little wiring as possible, while still having everything accessable in case any changes where required on short notice.

I knew that I wanted to take advantange of the fuselage side reinforcements to install the rudder servo tray. As there was already a similar tray on top of the wing tube for the fuel tank, I made a thrid one, angled between the other two, on to which I installed the powerbox and receivers. Under this angled tray I also built a “safe box” which separated the wires from any heat from the tuned pipes.

Knowing the placement of the powerbox, I could start routing the wires, amongst them the ones for the elevators and throttle. With the rudder tray prepared I could also up the required extention leads for the rudder servos also.

Due to the rudder servos being very close to the exhausts, I decided to make a small divider, from 2mm balsa with a thin layer of fibre, which would avoid the heat from the exhaust being able to affect the servos.

Using the same system I also closed off the area underneeth the powerbox, again assuring that no heat could affect the electrical components, or have any loose wires near the hot exhausts.

On the same support for the Powerbox I also mounted the two receivers, this way being able to make all the conections between them under this support before screwing the whole unit into the model with just 4 screws.

The ignition battery is placed at the very front of the model, thus gaining a little distance between the main electronics, and the engine electronics, as the Spark-Switch is situated just under the ignition battery. I chose the Spark Switch because it is so simple to use, with one channel it is either on or off, depending on the position of the switch (+100% or -100%) and no more adjustmeents are required. It also regulates the lipo down to 5,9v for the ignition.

*Click here to read the full article about the new Spark Switch by Powerbox-Systems:

The screen on the Powerbox-Systems Royal RRS is not only very neat, but also very usefull, both for day to day flying (to help know the status of your batteries) and also during programming. It can also tell you if there have been any problems with either receiver or the signal during the flight. For this reason I made the raised support, which makes it visible even with the canopy on.

Programming the Powerbox-Systems Royal RRS is very simple, especially with the screen to help.

*Click here to read the full article about the Powerbox-Systems Royal RRS:

The power to the servos is obtained through x2 Powerbox-Systems 4.000mAh Lipos, which after extensive flights can give 4 long (15 min) flights, and have just over half left. You could easily get more flights from them safely, however I prefer to change them after 4 for peace of mind (just as I do with all my models)

*Click here to read the full article about the Powerbox-Systems Lipos

*Click here to read the full article about the Powerbox-Systems Smoke Pump

If course, to protect the model I chose Revoc wing bags, Custom of course!

With the model finished, the range check and engine running all ok, it was time to take to the air!.

The maiden was easy, flew straight, no problems or hitches, just a great first flight. Now, after many flights I am really loving the plane, it is amazing how agile the plane is (especially for being a 3m plane). The rolls are so fast, and the rudder is amazingly powerfull, great for hard or even new manouvers.

The precision is great, it just goes in a straight line, no questions asked. And in 3D you can do anything yo want.

After a great season, I have used the Sukhoi to win many rounds in Unlimited Imac sequences, as well as the Spanish freestyle championship the SXFC, and even getting an 11th place finish at the European EXFC.

Even after all this, the more time that goes on the more I like the plane and the more used to it I get, so I am really looking forward to the results for 2012! Bring it on!!

Since the EXFC I have modified the setup of the Sukhoi, and I now have x4 servos per aileron (as opposed to the x3 used before) and I changed the rudder pull pull system with x3 servos to direct drive with just one on each side of the fuselage (x2 servos)

Many thanks to all my sponsors that have made it possible for me to put this model together.