Flyingaid InfoBase: Models

When you buy a new model there is always a learning period where you get used to the models personality especially where setup is concerned with horn lengths and tailoring your electronics to the model.

As time goes by I am going to add other models.

Knight 50

The Compass models Knight50 has been my weapon of choice since November 2005. It combines high specification, well thought out mechanics, excellent flight characteristics. I have found the model to be reliable and durable. It is also probably the most under estimated model available at the moment. It is growing in popularity by the day we now have 4 at our club out numbered only by the Raptor 50!

There are 2 versions available currently plastic tail and metal tail. My plastic tail has some slop in the tail pitch slider between it and the control forks. Don't really see the need to spend an extra £40

A third version will be available very soon. The fully plastic knight is looking like its going to retain the durability and accuracy of the metal knight at the fraction of the cost!

Recommended equipment

Beginner/intermediate pilot i recommend fitting Futaba S-3152s to the CCPM and throttle, with a Futaba GY401 with its accompanying servo the S9254. Best 50 size engine is definitely the OS50 hyper with the Curtis MP2 muffler. (more on this in the engines section). Governors are useful. I recommend the CSM rev-lock mounted on top of the throttle servo, its protected by the frames and keeps the cabling tidy. You can get away with a 3001 on the throttle but the governors work better with a digital. For the battery use a minimum of a 2000mah 4cell Sub C sized nicad. Sky is the limit above that, The fromeco regulators and battery's are good giving well over 10flights per charge.

For the reasoning behind these components see the electronics section

Advanced pilot by this i mean getting into backwards flight, pirouetting moves and tic-tocs. I recommend fitting futaba 9252 on the CCPM with futaba 3152 and a CSM rev-lock. Engine and muffler is OS 50 hyper and Curtis MP2. Finally a Futaba 611 gyro with its special servo. For the battery use a minimum of a 2000mah 4cell Sub C sized nicad. Sky is the limit above that, The fromeco regulators and battery's are good giving well over 10flights per charge.

Build

the Knight is ARTF, meaning there isn't much you can do wrong. It is worth pulling the pinion out of the pinion bearing and using red loctite as the pinion has a tendency to spin in the bearing wearing it out.

In one of the crashes i found that the impact had broken a fin off the fan. It appears the plastic is quite brittle, a common problem with nylon apparently. The fix is to put the plastic part of the fan into a mug of water and stick it in the microwave for a couple of min's. It should boil the water for about 1min. this puts moisture back into the plastic and makes it less brittle. Don't forget to take the magnet out if you have put it in already!

There are 4 screws holding the plastic servo tray onto the frames. The loads on the tray is quite high. I changed these screws for M3 bolts and nylocs. A little bit fiddly and needs to be done without the servos fitted but makes it a lot more solid.

When you fit the motor, loosen the pinion block bolts and make sure the start shaft spins freely this ensures correct alignment. check gear mesh and tighten the bolts using loctite.

Early kits came with blue dampers which are fine for normal flying. The red ones last a lot longer. Best results i have had is with Raptor 50 blue dampers. these are too long so need trimming not a difficult job if you have a sharp Stanley knife.

The final mod i have done is to move one of the balls on the mixer arms. This reduces the flybar ratio letting you use heavier more progressive paddles without the flip rate being too slow. This makes the cyclics very crisp, they start and stop sharply excellent for 3d but not really required. This hole is 3mm away from the pivot on flybar carrier. Ideally you would drill and tap to M2 but i didn't have an M2 tap so drilled a 2mm hole and bolt all the way through and fitted a nut on the back adding loctite.

Setup

As with any CCPM setup its important that the servo and all bell cranks sit at 90degs to each other at mid stick. using no sub trim 100% end point. Start at the servos get the horns right by trying different arms on the horn. I use the smaller futaba disks and drill a 2mm hole at 15mm from the center. The plastic of the wheels is slightly thicker than normal horns so makes them a bit stiffer. Metal horns look nice but it can be impossible to get them to sit at 90degs to the pushrod without using sub trim

From there adjust the length of the pushrod from the front servo to the A arm bell crank so that it sits horizontally.

do the same for the rear bell cranks check the lengths of the 2 sides so they are exactly equal. I use a cheap vernier to measure the lengths.

Now adjust the lengths pushrods up from the rear bell cranks up to the servo to get the swash level, again compare them to and get them exactly the same.

From there go up to the top mixer arms due to the length of the arms it puts the pushrod off of 90degs if you set it all up so the mixer arms are level. so you need to run them slightly short so the angle between the pushrod up from the swash plate up to the mixer arms sits at 90degs to the arm. Again use the verniers to get these 2 links exactly the same length.

Finally put a set of blades on it and check the pitch. adjust the length of the pushrod to the blade grip to give you zero degrees pitch. move the pitch to the top and bottom, check for binding reduce swash mix if it does bind somewhere.

Tail setup is fairly easy. Set the limits on the 611 to 120% set the sense and stick direction Then fit a 17mm horn on the servo at 90degs to the pushrod when the gyro is in the limit screen. Then adjust the length of the pushrod to give a small amount of right thrust. if you fold the tail blades there needs to be about 1cm between the tips of the blades. Set the gain to 37% on the front screen and your done. Same principal with the 401/9254

Set the rev-lock to give 17250rpm which equates to 2000rpm rotor speed. Unless you are on wooden blades then keep it under their specified limit which is normally 1750rpm. I find it useful to have a slower head speed for hovering it makes the machine smoother and less jumpy. Obviously if your just hovering then there's no need to have 2000rpm.

Blade sizes, 600mm main blades, 95mm tails with 3mm V paddles. Stock tail blades and paddles are fine for hovering. paddles are a little sharp its worth taking the point off it with sandpaper.

Header tank.

No mount is provided for a header tank on the knight. I mounted mine just below the rear fanshroud moun. Drill a 3mm hole in the frame. Push an M3 bolt in from inside the frames, put a nut on the outside followed by the headertank then another nut on the outside.

Canopy modification

The main thing i hear about the knight is "Wow if flies great but not sure about the canopy" So after my last canopy smashing crash i was left with a canopy that was basically in one piece but definitely not fit for show use. So took the opportunity for some experimentation.

First thing I did was move the front lower canopy mounting holes forward 30mm. This is easy to get the position of as the standard mounting point is marked with a small indent. This pushes the Canopy back onto the model this picture of the prototype should give you the idea. Note the 2 holes down the front and multiple holes up the back!

Moving the canopy back helped a lot but caused some issues with the upper rear mounts. they were too close to the upper edge of the canopy and the canopy in that area sits at a strange angle. the solution to this was to move the mounts down and forwards to just above the front bell crank. This has the great side effect of pulling the back of the canopy in tighter to the frame too which helps in fast backwards flight. The new position for the rear posts is occupied by 2 M3 bolts and a frame spacer. The M3 bolts were replaced with 3mm studding and canopy posts loctite onto the studding.

this was taken during one of my knights "maintenance periods" and shows the old location and the new position above the front bell crank bearings. Note the thumb screw on the post.

Before and after shots of standard canopy and the first show standard (not mashed) canopy. This particular one lasted about 10flights before i managed to kill it at 3dmasters!

Maintenance Tips

Day to day the Knight needs very little maintenance Obviously the normal points of wear such as ball links need to be kept an eye on. Other than that the main point of wear is the damping. Depending on your flying style it will last forever or a few gallons if you really abuse it. After a lot of flying I detected some wear in the washout hub this was replaced.

Its also worth inspecting the bearings of both sets of mixer arms occasionally and replace the bearings as needed. Be careful not to get loctite in these (or any) bearing.

Post Crash inspection

On top of the normal bits, Feathering spindle, Flybar, mainshaft which you will always break in a crash. I always replace the jesus bolts (mainshaft to head/main gear) its always worth inspecting the Mainshaft bearings. its a 2 min job (undo lower jesus bolt, links from swash and pull). The knight is more likely to damage these than other helis due to the metal bearing blocks The shock has to go somewhere, Having such a stiff frame structure has its price to pay and this is it.

Another place that can cause problems if you miss it is the frame spacer between the rear CCPM bell cranks. The bolts into these are only M2.5 and aren't the longest bolts in the world. Some change them for longer ones but its a nice cheap weak point that could save you the fiddly job of changing servo gears.

Common in a frontal crash is to bend the battery tray. Again another easy to change cheap part but in a heavy one you can bend the frame around the throttle servo. Its not the easiest thing to change as its part of the top frame or very structural so if you haven't totally mashed it its worth trying to straighten it up.

One very good part of the metal knight is the blade grips. The sheet metal pitch arms take a lot of the load in the crash which bends them. Nice and easy to change, cheap and in most cases will save damage to other components.