Okay guys

having inspired me over the years reading Sir Amer Ahmads interview has inspired me yet again to write another article.

We are going to start with the basic. The Aircraft.

ANY aircraft may be its a trainer or a 50cc YAK or a scale warbird or anything has the following basic parameters that need to be checked/adjusted in order for it to fly well.

I will start by a home check. stuff you need to see before you fly your plane.

1. check all bolts. nose to tail. use lock tight where ever you can. specially on gasers.
2. Make sure the wings and tail surfaces don’t have any warps. Perfectly fine planes when left in the sun ... ahem back seat of the car.... can develop warps. A warp is when there is a twist in the surface. To check a warp stand behind a wing or a tail surface and hold it at eye level and check for twists. In air it comes across as a plane that will not trim out in roll. I had a patternship with a warp kept rolling to the left then to the right as the speed went up or down. Anyways enough about warps.
3. Check the control surfaces.
- a - make sure there is no gap between the trailing edge and the leading edge of the control surface. No light gentlemen. Sealed tight.
- b - make sure that the hinge is not X-RAY. Please don’t use that it’s a man’s lungs or kidneys. Has no business in the air. USE GOOD HINGES they are cheaper than a new plane, receiver, battery, engine etc. Make sure you have free movements. In aerobatic machines with point hinges always check that if point hinges are used they are installed properly. To check this simply move the control surface to full deflection and see if the point of insertion of the hinge deforms under load. If it does erm ... go to a professional and have it fixed or do it yourself.
-c- check that there is no play in the control surfaces. TWO places where this play develops, one is in the control horn, the other is often that lousy Z bend at the servo. Keep everything tight and slop free.
4. Inside the plane.
-a- make sure that your batteries and receiver are secured using tie wraps and foam. The connectors are taped together. Nothing should be loose.
5. Lasting check for any dings, dents, oops I broke your plane honey and jeez sorry just had to check what it was made of. Hidden structural weakness will come and bite you in your behind if not checked and fixed at time.

Okay those are some of the basics that you need to be aware of all part of setting up your plane.
Till the next one
Take care.

Excellent guide! Thank you ... making it a sticky! :pp)

Good information ... Thanks

Aircraft Trimming

Test for Procedure Results Adjustments

Control Neutrals test response to each control Adjust trims for straight & level flight adjust clevises to center xmter trims
Control Throws Apply full deflection of each control Check for response; Aileron hi rate 3 rolls in 3 secs. Elevator, square loop corners Rudder, 35 to 40 Deg. Change control horns, ATV, and Duel Rates as required
Center of Gravity 1. Roll into a vertically banked turn 1. A. Nose Drops A. Add tail weight
Method 1 1. B. Tail Drops
2. Roll into inverted flight B. Add Nose weight
Method 2 2. A. lot of down required to hold level flight
(see Note A at bottom)
2. B. up elevator needed to hold level flight
Up/ Down Thrust, test 1 Fly model straight & level, then cut throttle A. Model continues level flight with a gradual drop A. No Change
Note Either change B or C requires retest of Decalage and Verticals
B.Model abruptly dives B. Increase down thrust

C. Model abruptly climbs C. Reduce down thrust
Up/Down Thrust, test 2 Fly model straight & level, then pull up A.Model continues straight up A. No Adjustment
Note Either change B or C requires retest of Decalage and Verticals
B.Model pulls to canopy B. Increase down thrust

C.Model pulls to belly C. Reduce down thrust
Decalage, Angle of Incidence Power off vertical dive from high altitude (neutralize elevator) A. Model continues straight down A. No change needed
(see Note B at bottom)
B. Model pulls to canopy B. Increase wing or stab incidence

C. Model pulls to belly C. Reduce wing or stab incidence
Knife Edge Pitch Fly model on normal pass, roll to knife edge, left and right, use rudder to hold model level A. Model does not change pitch A. No adjustment needed

B. Model pitches to canopy B. Either move CG aft; or increase wing incidence; or mix down elevator with rudder

C. Model pitches to belly C. Reverse of B;
Tip Weight - Test1 Fly straight; level, roll inverted, release aileron stick A. Model does not drop a wing A. No adjustment

B. Left wing drops B. Add weight to right tip

C. Right wing drops C. Add weight to left tip
Tip Weight - Test 2 Fly model towards you / away from you, pull tight inside loop, repeat with outside loop A. Model comes out with wings level A. No adjustment

B.Model comes out with right wing low B. Add weight to left tip

C. Model comes out with left wing low C. Add weight to right tip
Side Thrust Fly model away from you and pull up to vertical A. Model continues straight up A. No Adjustment

B. Model veers left B. Increase Right thrust

C. Model veers right C. Reduce Right thrust
Aileron Differential Fly model toward you, pull into a vertical climb before it reaches you. Neutralize controls then half roll . A. No Heading Changes A. Differential settings OK

B. Heading change opposite to roll command B. Increase differential

C. Heading change in direction of roll command C. Decrease differential
Dihedral Fly model on normal pass, roll to knife edge, left and right, use rudder to hold model level A. Model does not roll A. Dihedral OK

B. Model rolls indirection of rudder B. Reduce dihedral

C. Model rolls opposite to rudder C. Increase dihedral



Note A:These two methods for determining the C.G. of a model will give approximate results only. Start out with the C.G. where the Designer suggested, or somewhere between 25% to 35% of the Mean Aerodynamic Cord. The optimum C.G. for your model will require further testing while performing maneuvers. The results will only be an approximation at best.



Note B:This portion of the trimming chart may be unclear for the following reason;
In order to maintain level upright flight, the wing of a plane with a symmetrical airfoil wing needs to have a positive Angle of Attack (AOA, usually less than 1 degree). This positive angle provides the lift required to cause the plane to fly level. If the plane is balanced slightly to the nose heavy side (required for pitch stability), it will require a slight up elevator trim to hold level flight. A plane with a zero/ zero wing to elevator angle will also need a slight amount of up elevator trim to hold level flight. Therefore, a plane trimmed in this manner will have a tendency to pull to the canopy on a straight, thumbs off, down line because the elevator is controlling the AOA of the wing.

This positive AOA may also be achieved by a positive incidence change, which requires an offsetting down elevator for level flight. Thus, a power-off down line should fall straight down, with neutral controls. There are significant interactions between wing incidence changes and CG, therefore it is most important that the C.G. of the airplane be established first.

In the final analysis, flight trimming an airplane is a personal preference issue after you have taken care of the basic essentials.

Nice Information shared DEAR.

Dear Dr. Waqar:
I tried to contact you many times on your mobile but your never answered. You asked me for an Eagle and a box of 5 mins Epoxy. Your eagle and box of epoxy are with me for sometimes now. Kindly remit amount so that I can despatch your goods.

why not use X-Ray hinges?

x- ray hinges have been around for sometime...i thought they are only used in pak but looks like everyone is using it.

anyhow they are plain bad!!! they are as nasty as using ez-links on the elevator and aileron push rods..avoid at all costs....otherwise you are joking to your own self.

x-ray hinges are clear resistance free surfaces and can come out easily...one cannot realize but typically on planes over 40-size control surfaces can be under massive pressure at all times and a surface like x-ray hinge wont have the same grip and will lose its hold easily.

unfort. most of the locally made kits use them...avoid them at all costs.

what u need to do if u don't have a market hing for ur scratchbuild!

i used to make hinges from scotch tape with two plane chips! the scotch tape act as pivot between two chips of wood or plastic! it worked for me but these were small planes not the big ones!

www.hobbyking.com/hobbyking/store/__9041...x_Rx_V2_Mode_1_.html

it says the system has mixing function!

while u said it doesn't have! :-s