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Can I use automotive spark plugs with a SIM?

The SIM is compatible with all automotive and aviation spark plugs. SureFly’s FAA STC’s do not grant permission to use automotive spark plugs in FAA certified engines. You may only use spark plugs FAA-approved for your application.

Does the SIM output a tachometer signal?

The SIM outputs a 60Vdc spike with a 10Vdc offset on the p-lead (2 pulses per rev for 4 cylinder models & 3 pulses per rev for 6 cylinder models).

How is the SIM turned off?

The SIM is turned on and off with the existing ignition switch through the p-lead wire connected to the p-lead terminal of the SIM.

Should I replace the impulse or non-impulse magneto with a SIM?

SureFly recommends replacing the impulse coupled magneto. This is to reduce the possibility of impulse coupler mechanical failure and also to help the engine start better.

What are the advantages of a SIM configured for fixed timing over a magneto?

The SIM is a solid-state ignition module with the benefit of improved reliability and zero maintenance (no rebuilds & no overhauls) over the lifetime of the SIM. Another benefit is improved starting.

What does it weigh?

SIM4P - 4.4 lbs.

SIM4N - 4.0 lbs.

SIM6C - 5.0 lbs.

SIM6L - 5.2 lbs.

What is the service life of a SIM?

Return the SIM to SureFly for evaluation after 2400 hors of SIM operation.

What's in the box?

1. SureFly Ignition Module (SIM)
2. Power wire harness (84" long 14ga. wire with inline fuse holder, 10A fuse & ring terminals) If your battery is located in the tail of your aircraft, you will need to purchase a longer power wire.
3. Manifold pressure hose (36" long 1/8"ID x 1/4"OD high temp. rubber hose)
4. Engine STC paperwork
5. Airframe STC paperwork

Will the SIM help my engine start?

Absolutely! Compared to a magneto, the SIM provides a more accurately retarded spark and a more consistent, higher energy spark at low engine RPM. Hot-starts are greatly aided by the installation of a SIM, but keep in mind SureFly can’t remedy fuel system shortcomings!

How do I determine my sales tax exemption status?

State regulations require sales tax to be collected unless certain exemption forms or information is received. Sales tax is calculated based on the state and jurisdiction shipped to. Some states have specific general aviation tax exemptions and require shipping charges to be included in sales tax calculation. Sales Tax Exemption Wizard

How do I know my torque link is bent?

Use a straight edge as seen in Figure 1-3 to see if it's bent. 

Do I need anything else besides the torque link repair kit?

You might need a few of the NAS1149F0316P ultra-thin washers to fine tune the center “knee” joint fit on most of the Cessna airplanes. They are not included in the kit.

How do you remove torque link bushings to install new ones?

Removing the flanged bushings from the torque link forging can be difficult as there is not a good surface to press against or grab onto. An easy way to remove them is to thread them with a tap, screw a bolt in the thread you made, and then drive or press against the bolt. The thread does not have to be a full depth thread for the bolt to hold securely in the bushing. The bushing material is somewhat hard, but not so hard that a standard hardware store tap will not do the job. Use cutting oil on the tap to prevent tap damage. Normally the bushing will then come out easily.

For stubborn bushings, soak the link assembly in boiling water before pressing the bushing. The heat will expand the aluminum forging more than the steel bushing. This helps loosen the press fit while limiting the temperature to prevent from overheating and harming the heat treat of the aluminum forging. A controlled oven can be substituted for boiling water as a heat source, but do not exceed 350° F. Do not use flame or other non-controlled heat sources.

An alternate method is to put dry ice in the bushing before driving or pressing on the bolt you threaded into the bushing. Do not over-press or hammer as the aluminum can gall to the bushing and leave a damaged bushing bore. If the bushing does not come out with light to moderate force take the time to use some heat or cold to help.

I installed a torque link kit and serviced my shimmy dampener; why do I still have a shimmy problem?

There are many components all connected to keep the nose gear in line. If one component is worn or out of tolerance it can cause shimmy problem. Reference Dave McFarlane’s article: Can You Stop Nose Gear Shimmy instructions and suggestions.

Overlooked items also include the rod ends, shimmy dampener mounting and attachment, shimmy dampener, and steering collar. The steering collar is where the steering rod tubes connect and the upper torque link is attached to, along with the shimmy dampener on most aircraft. If the steering collar has play vertically and laterally and is allowed to tilt; that will cause excessive wear and force on the torque links, steering, and strut components. There are three different thicknesses of shims to help get the collar in place.

Ensure that the shimmy dampener is working properly with no dead spots in dampening action. The cylinder could be worn on the inside or on a piston that warrants replacement of components. All of the nose strut components are tied to each other and any movement is transmitted through to the tire and back through the dampening system, which if remedied will continue to be more pronounced.

Is the proper nut and bolt torque important?

It is very important to maintain proper torque for the bolts that clamp the chrome bushing/spacer at the upper attachments to the steering collar and the lower attachment to the nose gear strut. It is commonly thought that the chrome bushing/spacer is kept in position by the bolt filling the center bore of the bushing/spacer. This is not correct as the inner bore of the chrome bushing/spacer and the bolt are a loose non-precision fit. The bushing/spacer is secured by the bolt end, clamping the spacer so that it is tight between the arms of the aluminum forgings. Any looseness of this end clamp will allow movement of the chrome bushing/spacer. This movement will erode the aluminum forgings and create more free motion of the torque link.

All shimming of the torque links must be done with proper torque on the bolts. Periodically and during nose gear inspections, check the torque on the upper and lower torque link bolts. If the chrome bushing/spacer is allowed to move, the resultant wear can require replacement of the expensive aluminum forgings. McFarlane is working on a repair for the worn aluminum forgings. Unlike our competitors, extra care is given to the machining of the McFarlane chrome bushing/spacers to give the largest possible bearing surface to the ends that bear against the aluminum forgings. Chamfers or bevels are kept very small.

What does the Torque Link Stop Lug do?

The torque link stop lugs are more important than you would think. Overextension of the nose strut due to a worn out stop lug can lead to a cascade of problems. McFarlane A&P mechanics have seen struts over extend to the point where the metering pin comes out of the orifice. This results in loss of damping action and the pin hammering the orifice every landing and distorting and enlarging it. Over time, the excess nose strut travel and lack of damping can result in fatigue cracks in the torque link arms. McFarlane recommends thoroughly inspecting all nose strut components when replacing a severely worn stop lug.

The stop lug also acts as a centering device aligning the nose wheel and wheel pant straight with the airplane and slip stream after it has left the runway. Worn stop lugs can allow the nose wheel to lock in a turned position in flight that will require holding rudder for coordinated flight. Retractable gear aircraft depend on the stop lug to properly center the nose gear steering before it retracts into the wheel well.

What hardware is used for installation?

Our Vertical Fin Fitting kits include all the hardware needed for installation. You may receive NAS1149 hardware with the kit, which supersedes AN960 hardware (referenced in our ICA).