B196

OTHER: Miscellaneous - Safety

Accident Reports:

US Civil Rotor Accidents ~ 1963 through 1997

Robinson R-22 Accident Analysis 1979-1994

NTSB Aviation Accident/Incident Database

~ NTSB Helicopter Accident Survey

Wire Strikes: The highest cause of fatalities, in Robinsons, I believe.

Possible solutions:

Consider having the very front of the skids flare up and into the nose. This should eliminate the chance of a wire passing between the fuselage and the skids.
Consider locating a wire cutter above the canopy between the rotor hubs.
Consider break-away segments on vertical fin, plus perhaps a small lower vertical fin.

Low Rotor RPM: The second highest cause of fatalities in Robinson's, I believe.

Possible solution:

Rotor Governor;

Objects, Clearance, Visual Lookout & Loss of Control:

Possible solution:

An easier to fly craft should offer the pilot more time to observe external obstacles.

Hard Landing & Rollover: The highest cause of accidents in Robinson's.

Possible solutions:

Consider wider, stronger and more resilient landing gear.

Engine Failure:

Fuel/air mixture related accidents ... leading to the loss of engine power - about equals all of the Loss of Control accidents. ~ Journal of the AHS, January 2007, page 12.

Possible solutions:

SynchroLite Only: Idea: ~ Paint 4 quadrants of large pulley alternate black and white or belt. This way the operator can see, at a glance if and which engine has quit.

Loss of Control:

Yaw: Controlling antitorque in all flight phases is a root problem with single main rotor helicopter configurations. Yaw constitutes about 42% of the loss of control accidents. Cross-coupling between the vertical/power/RPM and the yaw axis is clearly excessive. ~ Journal of the AHS, January 2007, page 12.

Vertical:

Roll:

Pitch:

Re; Ultralight Category:

I think there should be a good chance that components on the SynchroLite and Dragonfly, which are directly related to safety should not have to be included in the 254 lb limitation.

These items would be;

Rotor governor.
Rotor brake.
Chip detector in transmissions.
Chip magnet in transmission.
Detector of maximum applied torque.
Detector of maximum temperature.
All active sensors ( on console) of engine, power train and rotor performance. I.e. oil temp gauge etc.
Seals on 'certified' units, to show that these units have not been modified by non-certified individual.
Shock absorbing landing gear.
3-cylinder engine. Might even be able to argue that a derated 3-cylinder engine, which weights approximately 20 lbs more, is a safety device since a 2-cylinder engine can certainly do the basic job.

Misc. Notes

Minimize descent rate and weight on landing:

SynchroLite Only: Crazy Idea - Consider having quick pull pins which will drop the 2 engine/redrive/centrifugal clutch assemblies and also the fuel tanks.

Engine out w/ 2 engines:

SynchroLite Only: Consider having the muffler (if std. Muffler and not tuned exhaust) and the intake silencer as removable. This way if one engine quits then 1/ more power can be obtained form the other and 2) people may be more inclined to notice the helicopter.

Large Mass of the Power Train and Rotors:

UniCopter Only:

There is much weight in the power train, rotors and engine, which are located above and behind the pilot.

Black Box:

On the news last night there was a segment mentioning that everyone of this years GM cars has a black-box under the drivers seat. This device records the vehicle's speed, application of brakes, deployment of air bag, and numerous other activities. In the event of an accident, this information could be used by GM, the insurance company, or the police.

It appears that the safety of light helicopters, and particularly recreational gyrocopters, could be much improved if this black-box was modified, or a similiar ecconomical device manufactured, for use in 'entry level' rotorcraft.

Remote Flying:

Consider flying the helicopter by remote control for testing. This could also serve as development of a remotely piloted vehicle.

Also, consider the use of one or more parachutes and one or more air bags. This way, if a part breaks in flight; 1/ the craft can be recovered with little other damage and 2/ it will be a heck of a lot easier to se what broke and how.

Danger re Loose Clothing or Objects: June 1, 1999

SynchroLite Only:

There is a strong chance that loose articles of clothing, such as Snoopy's scarf would be caught in the belts and pulleys.

During flight, a hard object may "fly" into the belts and pulleys and destroy them.

Consider forming some light screening from the backboard back about 12 - 18". This will still allow air to get through, it will weigh very little and it will give "shape to the helicopter.

Or just screen off each belt, individually. This screen might be part of protection between belts and control rods. It might also be made stronger and serve as part of the frame in taking the tension load between the 2 sheaves.

A flammable object may make prolonged contact with a hot engine. This is not too likely.

Safety Factor:

OTHER: Mechanical - Safety Factor:

DESIGN: UniCopter ~ Rotor - Hub - Design Considerations

Personnel on Ground:

This is only of concern with small intermeshing helicopters.

All very small helicopters have a problem with clearance between the blades and the ground, with the possible exception of the UltraSport 254. The Brantly shows an elevation of 2.02 m (6' - 7") from the center of its hub to the ground. The single seat teetering-rotor Helicycle is another example. See Related Information on the Helicycle.

The center of the hub to the ground on the Dragonfly mockup is 1.78 m (5' - 10"). The center of hub to the ground on the UniCopter mockup is 1.75 m. (5' - 9"). In addition, the blade tips will be even lower at the sides of these two craft.

Note:

Regular landing sites can be configured to eliminate this danger but random landing sites cannot.

Written Warning:

A sign on both side (large enough that they don't have to come close to read it).

Rotor Brake:

Perhaps rotor disengagement and a fast acting rugged friction rotor-brake may overcome this problem.

The UniCopter will be able to handle a fast RRPM deceleration because its design mandates a very rugged rotor and power-train. The Dragonfly's drive-train must be reasonably stronger than those on single rotor craft, therefore a couple more pounds of strengthening to handle a reasonably fast rotor-brake should not be a problem.

In addition see; DESIGN: Dragonfly ~ Control - Flight - Directional - by Tip Brake ~ Rotor Brake

Opposed Lateral Cyclic:

The intermeshing helicopters use opposed laterally cyclic in forward flight. A solution to low blade tips at the side might be might be to apply full opposed lateral cyclic while the craft is sitting on the ground This could be used while the rotors are turning and stationary. In addition, the cyclic should probably be locked in the central position.

Horn:

Located on fuselage.

Strobe Light:

Place a strobe light in the center on top of the "overhead" bar connecting the two swashplate-mounting posts. Its purpose is to keep personnel on the ground and aircraft in the air away.

Blade Tip Lights: *

Run a pair of wires down the blades. They can be possible be used for tip lights, as a safety feature. The wires could also be temporarily used for locating very small and light sensors at the blade tips. They would also have an aesthetic value.

Blade Tip Whistle: *

Consider locating a whistle in each blade tip and a simple air valve in the hubs. The whistle and the valve are connected by the passageway that the blade's tip light wires run in. Opening of the valves will allow air to flow in the passageways and this flow of air will cause the whistles or cause the cessation of the whistles. For additional information see: [RWP1 p.304]

For Dragonfly see; DESIGN: Dragonfly ~ Control - Flight - Directional - by Tip Brake ~ Tip Whistle

Blade Tip Streamers: *

Run a cable down the blades, which is attached to a streamer that has a small weight on its end? Centrifugal force will pull the streamers out and some mechanism in the hubs will retract the streamers. The small weight could also be the whistle.

Option: Use leather streamers to whip anyone who does not obey the written warning and gets to close.

* The tube down the center of the blades might be required to manufacture the UniCopter blade (pultruded spar).

Paint Blade Tips:

Paint the blade tips in a color (silver on top of blade tip?) that contrasts with the normal background color.

Visual Smoke:

Eject a colored smoke out of the tip aperture while the craft is on the ground with blades rotating. This may produce a ring, if there is no wind.

Ballistic Parachute:

To be used upon a potentially craft damaging catastrophe.

BRS Home Page

#500 Canister - Capacity = 500 lbs, Weight = 20 lbs, Dimensions = 18" long x 7" diameter.

#750 Canister - Capacity = 750 lbs, Weight = 23 lbs, Dimensions = 18" long x 7" diameter.

The canister might be located in the top center of the 'T'-tail and attached by cable, down the vertical stabilizer and boom to the drive train and engine. Upon deployment, the stabilizer may brake off but so what. This cable might have a 'bunge chord' located at some location alone its length and thereby give some additional restraint to the power train upon the crafts contact with the ground.

The craft will descent with a nose down attitude therefor the lowering of the nose landing gear and/or the deployment of an airbag outside the nose and/or in the cabin may help.

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Last Revised: February 16, 2007