SHOULD RECONFIGURABLE ARRAYS BE ALLOWED?
A reconfigurable array is one that is allowed to be carried by the vehicle in a different configuration than what is used during stationary charging. Reconfigurable arrays were not allowed in 2003, though they were allowed in early Sunrayces.
A change to allow reconfigurable arrays could be written to allow for different amounts of reconfigurable area. For instance, a regulation could call for a minimum amount of array exposed while driving, or could not set any minimum amount.
What are your thoughts? How to submit your response.
RESPONSES(Generally listed with newest response first.)
RESPONSE#6
A couple comments inline:
In other words:
- all hardware associated with the reconfigurable array, including any supporting structure, must be a part of the car during driving and remain part of the car during stationary charging
I agree completely, and I think this should be a key part of any
reconfiguration requirement. Adding suplemental panels that are only
supported by the charging structure would not seem to be in the spirit
of having a solar array on a solar car.
- the wheels of the car must remain in contact with a horizontal parking surface during stationary charging
I don't think this really should be a requirement. Most every team
tends to have an array that lifts of the chassis containing the wheels
anyway, but this would limit teams that for some reason or another want
to build a one-piece car where the array is permanantly attached to the
chassis and the whole car needs to be rotated for charging. We haven't
seen it yet, but there doesn't seem to be a need for this requirement.
- a single person must demonstrate the ability to perform the reconfiguration within a two minute timeframe
Very hard to demonstrate and really somewhat unrealistic. It already
takes most teams 3-5 people just to lift their array off their car to
put it on a charging stand, why then require only one person to slide
out supplemental panels. If one person can't deploy the entire array,
it seems unrealistic to require that only one person has to deploy just
a section of the array. I don't think this needs to be a requirement
either.
And, there should probably be some sort of size limitation, perhaps related to the projected area of a standard parking lot space.
The reconfiguration that was allowed in the past was limited to the
standard solar array box that has been defined in every race's regs.
The way to obtain additional suplemental array area was to define your
box such that the array in charging confiuration was measured across the
diagonal of that box, yet still fit within the box. Your size
regulation is already contained within the regs and does not need to be
changed.
FROM: Jason Kramb,
University of Michigan Solar Car Team Alumni,
Driver / Chief Aerodynamics and Body Engineer '99,'01
RESPONSE#5
If we decide to go back to reconfiguring the solar array, let's make a
clear rule of how large the reconfigured array can be. The imaginary
box rule that was used in the past didn't work well - it was difficult
to interpret and almost impossible to enforce. It is ok with me for
teams to reconfigure, as long as we have a clear rule.
My honest opinion is that reconfiguring to add a few extra panels during
the charging periods will not make a significant difference in the
overall performance of the car. The charging periods are short and it
isn't that much extra energy even under optimal conditions. If the
array on the car is capable of fully charging the batteries, the extra
panels do not provide any extra energy.
Team New England used a major reconfiguration in the 1995 Sunrayce event
- maybe that is what people are thinking about. (They had a very small
car with the solar array folded up and carried inside, and only charged
in the mornings and evenings.) It worked well on sunny days in Sunrayce
because they only had to drive 4 hours a day and travel 150 miles or so.
In ASC there probably isn't time to set the array up and take it down at
the 30 minute media stops, and the limited charging time in the mornings
and evenings will mean that a car using this strategy will not have much
energy to work with. It is ok with me if teams try this approach, but I
don't think it will work out very well for them in ASC.
FROM: Doug Carroll
RESPONSE#4
I have always been in favor of fewer and fewer regulations that limit
the innovation and design options for the teams. I think that
reconfiguration should be allowed at any time. It would have made the
extremely innovative camber changing fairings of Waterloo a non-issue
this year, plus would allow for all types of different designs for the
use of suplemental panels or other aerodynamic assist. Teams that
wanted to use suplementals would sacrifice the weight of the additional
array panels and their support structure. This does however bring us
back to the original discussions of speed and the racing day. By
potentially adding more array power to the equation, speeds will
obviously not come down and racing will still have the problems it did
in the last race. This would also require moving back to measuring
entire solar arrays, in their all of their configurations, during
scruitineering. Still, I belive design freedom is the key, and that
many more innovations will results from removing restrictions on
reconfiguration.
FROM: Jason Kramb,
University of Michigan Solar Car Team Alumni,
Driver / Chief Aerodynamics and Body Engineer '99,'01
RESPONSE#3
I think reconfiguration is a reasonable concept, provided that
practicality be considered. (Here I go again on practicality...)
When I was on the Rose-Hulman Solar Phantom III team in Sunrayce 95, we
had auxiliary solar panels that could be removed from the underside of
the car and attached to a charging fixture to expand our array during
stationary charging. This was a tedious process that required several
trained individuals to accomplish, not to mention a separate truck to
haul the fixture. From a spectator standpoint, this does not seem
practical.
However, if a car was devised to have simple fold-out or slide-out
panels, this might be perceived by spectators as something they could
actually do after they park their car; akin to putting a convertible top
in place after parking.
I propose that reconfigurable arrays be allowed, provided that they can
be reconfigured by just one person in some reasonably defined time (such
as two minutes). However, I also propose that the array stay attached
to the solar car, and that the solar car's wheels remain in contact with
a horizontal parking surface during charging (in any configuration).
In other words:
- all hardware associated with the reconfigurable array, including any
supporting structure, must be a part of the car during driving and
remain part of the car during stationary charging
- the wheels of the car must remain in contact with a horizontal parking
surface during stationary charging
- a single person must demonstrate the ability to perform the
reconfiguration within a two minute timeframe
And, there should probably be some sort of size limitation, perhaps
related to the projected area of a standard parking lot space.
When I think about driving a practical solar car some day, I can
envision pulling into a parking space and then folding out some
auxiliary panels. However, it is difficult for me to perceive that I
would unbolt the array from my car and attach it to a separate array
fixture that my friends happened to bring along in a big truck. That is
where I am coming from.
Also, an award for the most practical implementation might encourage
creativity.
Regards,
FROM:
Carl,
Sunrayce 95 Participant
RESPONSE#2
Dan:
I seem to remember the change from '95 to '97 was
getting rid of reconfigurable arrays in exchange for
the cut-out rule.
Everyone:
I've been reading the discussions for some time and
have kept quiet, but I would like to throw my $0.02
worth into the hat.
I think anything that presents new/different design
trade-offs is good thing. It leads to more creative
engineering in the programs. That said, I think it
would be a fair trade-off to say that teams can have
reconfigurable arrays. However, the support for those
modules must be carried in the solar car. Teams can
carry their normal charging structure in a support
vehicle to support the main section of the array, but
the support for supplemental pannels must be carried
in the solar car.
In more general terms though, maybe reconfiguration
should be allowed during any part of the day as long
as the reconfigurable parts and their supporting
structures are carried in the vehicle. Demonstration
of the possible configurations would be required at
scrutineering but would not necessarily have to be
'live' during qualifiers.
Like I said, just my $0.02.
FROM:
Russ Moerland,
University of Michigan Solar Car Team Alumni,
Strategist '97 - '01
RESPONSE#1
Reconfiguring should be another design option available. As long as panels
deployed while racing are not wider than a Hummer, it should not create any
issues with safety (at least any additional issues, than what we already
deal with). It creates another system of the car that can be innovated
on...
FROM:
Jason Halpern,
University of Minnesota - Twin Cities,
Mechanical Engineering,
Team Manager,
Solar Vehicle Project
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