1. VMAR - Landing Gear - General Information
1.1. Landing Gear - Adjusting Height and/or Nose Up/Down Angle

Question: How do I adjust the nose up/down angle on my trike gear model?

Answer: Generally the nose gear can be adjusted slightly up and down so that the wing is near zero incidence (level) when the model is on the ground. If the nose is pointing up, the wing will be flying when the model is on the ground and you will tend to porpoise up and down when landing. If the nose is pointing down a high ground speed and excessive up elevator is often necessary to get the model to lift off.  

To adjust the nose up/down angle of the model when it is on the ground, you can do several different things or combine these things to get the desired result.

Lengthen the gear leg by loosening the set screw in the steering arm and pulling the gear downward or shorten the nose gear by pushing it upward slightly and then reseating the set screw.

AND/OR

A different nose wheel can be installed. Increasing the nose gear diameter by 1/2" will lift the nose approximately 1/4" higher with respect to the ground. So instead of a 2.5" wheel for example, try a 3" nose wheel. Do the reverse if you want to drop the nose lower towards the ground.

AND/OR

A different set of main gear wheels can be installed. Decreasing the main gear diameter by 1/2" will lower the center of model by approximately 1/4" with respect to the ground and at the same time reduce the degree of nose down attitude. So instead of a 3 " main wheels for example, try 2.5" main wheels. Do the reverse if you want to drop the nose lower towards the ground.

Note that by combining changes to both the nose wheel and the main wheels, a great deal of adjustment can be done to the nose up or down angle of the model when on the ground.

1.2. Landing Gear - Main - Wire Tight Fit into pre-drilled Holes

Question: I am about to install the main landing gear which is made from plated wire. Each gear "leg" is to be inserted into a pre-drilled hole in the bottom of the wing or fuselage and then aligned with a slot and clamped down with retaining straps. I find that it is difficult to insert the wire into the pre-drilled hole... either the wire is a touch too wide in diameter or the pre-drilled hole is a bit too narrow. Should I tap the gear legs into place with a small hammer or what?

Answer: If you can tap lightly and rotate the wire slightly to and fro a few times that will often work. If you find that it is a really tight fit and light tapping is not sufficient it would be best to take a few minutes and drill the hole out or grind the end of the wire.

Better Answer: Have a look at the wire first. Is there a burr or slight flairing at the end of the wire where it has been cut? If so, file the end to a slight taper. If the wire has no burrs or flairing at the end, the problem is likely that the wire is slightly oversized due to the plating and/or the pre-drilled hole has narrowed just a bit as the wood has dried after production. Either way, drill the hole out one size bigger. Here is how to do that... select a drill bit that is just large enough in diameter to barely fit into the hole without having to actually drill. Insert the drill into the hole and note how deep the hole is. Now select a drill bit that is 1/64" to 1/32" bigger in diameter. Apply masking tape to this drill bit to mark the depth of the hole. You don't want to overdrill the depth or you run the risk of drilling through a wing or other surface on the opposite side. Now use this larger drill bit to drill out one landing gear hole. Remember the idea is to increase the diameter of the hole slightly... not to drill deeper. Test fit the gear again. Then drill the second hole. Clamp the gear down with the retaining straps and screws.

If you ever end up with a hole that is too large and the gear has a loose or sloppy fit, turn the wing or fuselage so that the wheels are pointing up. Align the gear carefully so it is straight. Slide 1 or more narrow tooth picks into any slack space between the gear leg and the side of the hole. Flow CA+ such as ZAP-A-GAP CA+ from PACER down into the hole and around the tooth pick. Let the CA+ cure or accelerate with a light mist of ZIP KICKER. The gear should be nice and tight when you are finished.

1.3. Landing Gear - Main - Modification For Strength

Question: My landing gear appears to be made from aluminum or fiberglass. Is it possible to make it even stronger?

Answer: Yes. Please see the attached guidance for after market modification.   

1.4. Landing Gear - Nose - Alignment
Question: The nose gear on my VMAR model is steerable. I am having trouble aligning it so that it is centered (straight ahead) and so that I have some movement to both the left and right. What should I do?
 
Answer: Most VMAR models use a steering arm attached to a control rod and a servo. The steering arm is then slid over the nose gear wire or cylinder and locked into place with a set screw which engages with a flat spot that has been pre-positioned on the nose gear.
  
To resolve alignment problems:
 
1) Turn on your radio and center the servo that will move the nose gear.
 
2) Slide the steering arm into place on the nose gear, rotate the gear so that it points straight ahead. Cinch down the set screw. Check left and right movement. If you have more or less all the movement in just one direction, remove the wire gear and grind a new flat spot onto the wire at a location to allow the steering arm to engage with the wire and still rotate equally to both the left and right.
 
3) Remember that the amount of deflection to the left and right does not have to be large to enable nose steering. Slight left and right movement is all that is necessary.
 
4) In some cases, it may help to remove the steering arm and flip it over so that the distance between the firewall and the arm portion of the steering arm assembly is maximized. This stands the steering arm off from the firewall and enables the servo to "pull" more and hence turn the nose gear more before the arm contacts the firewall.
 
 
 
 
1.5. Landing Gear - Nose - Number of Wheel Collars

Question: My assembly manual has a picture showing one wheel collar holding the nose wheel in place and this matches the one collar found in the parts bag. However the manual mentions the use of two collars. What's the story here?

Answer: Depending on the model and the parts packing, there is always at least one wheel collar provided for retaining the nose wheel and only one wheel collar is required.

In some cases, we have also included an extra wheel collar in the parts bag in case of loss. Modelers can retain this extra collar in case they need it OR may wish to install the wheel collar on the nose gear axle inboard of the wheel itself.

1.6. Landing Gear - Oleo Struts
1.6.1. Simulated Plastic Oleos - Can I buy them separately?

Question: Many VMAR semi-scale models come with pre-installed landing gear struts. Can they be purchased separately?

Answer:  Yes they are available separately as an after market item. Best to call our order desk at 604-940-1066 or order on line. There are two sizes... roughly for 45 size and 90 size models. There are white or grey colored versions of both sizes. They are searchable on our web site as part numbers that begin with VMA-STR or search for "strut". They are sold as single sets for one gear leg at a time. Please have this information at hand if you are calling our order desk.

Please note that the plastic clamshell like struts are decorative only. The two halves wrap around the internal wire gear. They are not functional and do not bear weight.

1.6.2. Simulated Plastic Oleos - Appear to Be Cracked or Split

Question: My model came with simulated plastic oleo struts on some of the gear legs. They appear to be cracked or split. What should I do?

Answer: The simulated plastic oleo struts are a no-charge bonus item included with many of the scale and semi scale models. Even some of our high end trainers use these on the nose gear. Each simulated strut consists of two clamshell like plastic halves that "wrap around" the wire gear leg and are retained in place usually by a couple of small screws and a plastic ring and/or adhesive.

These struts are not functional, they are decorative only. Under load and/or during shipping the seams between the clamshell halves and/or the retaining ring can open up and expose a small gap along the seam. We suggest carefully tightening the screws again and regluing the clamshell halves and retaining ring back into place. Plasti-ZAP or ZAP-A-GAP from Pacer work well on this plastic.  

These simulated oleo struts are also available for purchase as a part. Please see the Replacement Parts section of our web store and search for "strut".

1.6.3. Simulated Plastic Oleo Struts - Can they be relocated to Retracts on Retract Ready Models?

Question: I have a VMAR model that comes with fixed landing gear and is considered retract ready so that I can install my own retracts at a later date. The fixed landing gear has simulated struts surrounding the wire gear legs. Can these simulated struts be moved to my retractable landing gear?

Answer: Quite likely yes but they may require some modification. There are large number of different retract systems and the only way to really be sure is to remove the simulated struts from the landing gear legs on your fixed gear and to trial fit them to the gear legs on your retracts. If they fit, then carefully confirm that the retract can operate freely with the simulated struts in place.

1.7. Landing Gear - Retracts - How to Install - Instructions.

Question: I have a VMAR ARF that is Retract Ready. Where do I get installation instructions for retracts?

Answer: The installation instructions for retracts are provided by the retract manufacturer. The procedure can be quite different from retract to retract depending on the brand and type. Please consult with the retract manufacturer for installation instructions.

1.8. Landing Gear - Retracts - In VMAR ARF's - Which Type?

Question: I have a VMAR ARF that is Retract Ready. What retracts do you recommend?

Answer: We actually don't recommend a particular brand of retracts. Modelers have their own preferences which vary dramatically from region to region. Some prefer a particular brand while others prefer mechanical or pnuematic (air). There is no "right" recommendation.
 
When we are designing mounting rail size and placement and bolt patterns etc we use Robart Pnuematic #ROB-605HD Main Gear, #ROB-607 Nose Gear and #ROB-188 Air Control Kit. (Please contact Robart to confirm suitability, size, bolt spacing, weight range, pricing and availability in your market area)
1.9. Landing Gear - Trike vs Tail Dragger - Whats what? What works Best?

Question: What is the difference between Trike and Tail Dragger landing gear?

Short Answer: Trike models have a nose wheel and two main wheels. Tail dragger models have two main wheels and a tail wheel or tail skid.

Better Answer: Trike is slang for TRI-cycle... TRIke gear uses 3 wheels and looks much like the front and two main wheels of a kids tricycle... hence the name Trike Gear. Think of a kids tricycle and you know what it looks like. The front wheel does the steering.

Tail Dragger is a slang term for aircraft that do not have a nose wheel. Tail draggers have main landing gear and a tail skid or tail wheel. Generally we think of Tail Draggers having only the two main wheels but in fact they may have a small tail wheel as well. On some models the small tail wheel is coupled to the rudder so that the airplane can be steered left and right more easily when it is taxiing on the ground.

In general, and there are lots of exceptions... trainers have a high wing and trike gear. Most beginners who are learning with a trainer and many other RC flyers find trike models easier to steer on the ground provided the runway is smooth and the grass is not long. For rough fields or runways with coarse gravel or longer grass, trike gear can be a problem and tail draggers work better. Some trainers and lots of sport and scale airplanes are tail draggers. Some trainers give you a choice... trike or tail dragger... the VMAR Apache for example offers both configurations with all the parts in the box for either set up.

1.10. Landing Gear - Wheels - Diameter - Is it OK to change from stock?

Question: Is it OK to change to smaller or larger diameter wheels? Any tips on this?

Answer: Depending on the model, the stock wheel diameter has been chosen to work well on asphalt, packed sand/dirt /&or close cropped grass. Yes it is OK to change the diameter of the wheels provided that you maintain the same angle of incidence when sitting on the ground... i.e. if you change the diameter of the mains you must change the diameter of the nose or tail wheel by the same amount and vice versa.

Here are some tips:

  1. The angle of incidence on the ground should be the same as that provided by the stock wheels to ensure that the model has the correct angle of attack when making its take off run and when landing. i.e. if you change the mains by X inches in diameter, make sure you change the diameter of the nose or tail wheel by the same amount and vice versa.
  2. If you are always flying from smooth asphalt, concrete, clay or other very hard surface, you can reduce the wheel size slightly provided that you retain sufficient prop tip clearance from the ground. You may have to opt for a smaller diameter prop with a larger pitch or more blades to sustain sufficient ground clearance for the prop.
  3. If you are flying from packed dirt, fine gravel, sand, sandy soil or closely cropped grass, the stock wheel size is probably best unless you have some particular need to change the wheels.
  4. If you are flying from a grass field where the grass is quite long and/or the turf is soft or spongy or variable in "hardness" you may need to go to larger diameter wheels to get consistent ground handling and stability. If your model appears to be bogging down on take off, failing to run out smoothly upon landing or is hard to taxi in a straight line try increasing the diameter of the wheels in .25" increments. Use lightweight wheels and test as you increase the diameter in .25" steps. Generally trike gear will require larger diameter wheels in these conditions than tail draggers due to drag on the nose gear wire/axle.

 

1.11. Landing Gear - Wire vs Fibreglass vs Aluminum - Whats what? What works best?

Question: What is the difference between landing gear made of wire vs that made of fibreglass or aluminum?

Short Answer: Wire gear is OK for just about any model particularly low wing models with short landing gear legs. When the landing gear legs are longer such as on a high wing trainer or sport tail dragger, fibreglass or aluminum is best. We are now using 7075 T6 aluminum on many models because it is as strong or stronger than fibreglass gear and much lighter.  

Better Answer: When wire gear is used it tends to bend easily if long and on an angle. This can actually be a help when training because the bending sucks up some of energy associated with a hard landing. Re-bending wire back into shape quickly becomes tedious in spite of it's low cost and energy tolerant attributes. So for example on our Discovery, Challenger and Hornet trainers where entry price is critical we use wire gear and offer stronger gear as an aftermarket upgrade. On the slightly higher priced Apache we include heavier duty gear made from either fibreglass or 7075 T6 aluminum. Both are exceptionally strong but aluminum is now favoured due to a lighter weight. Softer grade T6 or non-T6 aluminum does not stand up well in service. Beginning in the second half of 2003 we began changing most of our sport and semi-scale models that had fibreglass main gear over to 7075 T6 Aluminum. We continue to use Fibreglass when the leg length is very long such as the 120 Size Beaver.

 

 

1.12. Landing Gear - Wire Coil Direction - Which is Right?

Question: My model has landing gear made of wire. The wire has a shock coil just below the fuselage. There are two ways to install this gear. Which is correct?

Answer: The landing gear should be installed so that the coil winds up (tightens) when the landing gear contacts the ground. There are a few exceptions for reasons of scale appearance and/or softening the shock of landing but these are rare.

1.13. Landing Gear - Wire Coil or Not? Which is right?

Question: If the picture in my instruction book shows a wire coil and my landing gear does not have a wire coil or vice versa... if the instruction book shows no wire coil and my landing gear has a wire coil... do I have the correct landing gear wire set for my model?

Answer: Most of the time yes. If the landing gear fits into the slots and accomodates the wheels and results in the correct ground height for your model you are going to be OK to use the landing gear provided with or without a coil in the gear.

Better Answer: The instruction books are laid up early in the production cycle of a model. At times we change the gear to add or remove a coil depending on what we learn from users. Ideally we would have it right from the get go but if we find that a landing gear is too "springy" in operational use, we take the coil out in the next run. Conversely if we find that the gear is too stiff in operational use, we add a coil in the next run. Either way, the main thing is that the gear fit correctly into the mounting slots and provide the correct ground height for your model when using the wheels provided.