Ed Anderson wrote:
Paul,
Regarding your request for inputs on the alternate engine juding
criteria: Here is some thoughts I put together on the topic. I don't know
if there is anything here useful to you or not, but feel free to use it as
you see fit.
Ed Anderson
Alternate Aircraft Engines and Evaluation Criteria (Draft)
Purpose of Award(s): To recognize and encourage safe and well thought-out
alternate engine (non-aircraft) experiments in keeping with the educational
and recreational charter of amateur build aircraft. The primary focus is on
the FWF portion of the installation. However, unique or innovative engine
instruments, exhaust systems, or control or auxiliary systems which are
essential for safe engine operation are included in the FWF definition even
if not actually forward of the firewall. The idea is to promote the
development of less expensive and safer power plants for amateur built
aircraft.
Eligibility for Category
1. The aircraft must be currently certified under the experimental amateur
build category (to preclude deep pocket commercial ventures from winning the
award with their engine developments)
2. The engine installation was not purchased as an engineered package or
part of a commercially available kit.
3. The engine installation must primarily be a result of efforts of the
aircraft builder or a partner who participated in construction of aircraft.
4. The aircraft powerplant was not originally designed or offered as an
aircraft powerplant
5. The aircraft must be currently in flyable status and at least 100 hours
of engine flight time has been accumulated.
Judging Criteria (Candidate factors)
1. Installation and airframe must be considered to safe in accordance with
normal aircraft installation and maintenance practices. Specific areas that
should be considered for evaluation are:
a. Engine Mount (Engine securely fastened to mount and mount to airframe)
b. Fuel System (Fuel pumps, lines, etc connected and protected IAW aircraft
practices)
c. Exhaust System (Vulnerable subsystems protected form heat)
d. Control System (Fail safe design, i.e. butterfly plate in throttle
body/carburetor opens in case of cable/control failure, redundant CPUs, etc
if EFI)
e. Cooling System (Safely secured to airframe and coolant lines protected)
f. Propeller Speed Reduction Unit (if not direct drive)
g. Engine Instruments suitable for installation (example: if water cooled
then coolant temp and coolant pressure gauge, fuel pressure gauges, etc.)
h. Propeller (If non commercial variable pitch or of unique design)
2. Given experimental nature of Alternative Engine Installations,
special/additional credit should be considered for:
a. Evidence of special attention to "Fail Safe" or "Graceful Degradation"
features of design such as Dual/Redundant System components so that failure
or malfunction of one would still permit safe flight. This could include
dual batteries, ignition system components, fuel pumps, etc.
b. Presentation and availability of Technical Data regarding the engine and
subsystem installations. Idea is to encourage dissemination of information
regarding the installation to others that may wish to adopt it.
c. Unique solutions to typical alternate engine conversion such as propeller
speed reduction approaches. These units are normally composed of belt or
geared components. Other approaches (such as automatic transmission
concepts (liquid coupling of power to prop), variable pulley arrangements,
etc as examples).
3. Performance Considerations
(Given the difficulty and cost of collecting, analyzing and interpreting
empirical performance data this is one area that is probably the most
subjective and difficult to objectively judge. While it would be useful to
be able to evaluate this area, I think at this time it would be too
subjective to merit consideration as a judging criterion at this time. )
4. Other Considerations
Judges may want to consider inputs from alternative engine participants.
Consideration may be to have such invdividuals who have NOT requested their
aircraft to be judged advise the judging team.
Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com
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