Control Line Navy Carrier - 2004/05

May 2004 153
THIS MONTH I will write about the
exciting events planned for this summer,
some expanding activities in Nostalgia
Carrier, and include a bit of technical
information about tailhook placement.
Be sure to make plans to go to Muncie,
Indiana, in July. The United States is
hosting the CL World Championships this
year at AMA’s International Aeromodeling
Center. Although there is no FAI Navy
Carrier event, two demonstration events will
be flown during the contest.
On Saturday, July 10—the last day of the
World Championships—the Navy Carrier
Society (NCS) will sponsor AMA Profile
Carrier and AMA Class I Navy Carrier. The
Profile Carrier event will be flown
according to AMA rules. Class I will use
AMA rules with 10% fuel supplied by the
contest sponsor.
With the 10%-nitromethane limit and
mufflers allowed, the NCS hopes to
encourage Carrier modelers attending the
World Championships to bring their Class I
models and enter the demonstration event.
We anticipate having awards that will be
appropriate for an international event.
This will be a good opportunity for US
Carrier modelers to come a little early, enjoy
the CL World Championships, fly an extra
Carrier contest, and have three days for
practice and for watching other CL
Nationals events before the Nats Navy
Carrier competition. It should be a great
time and something you won’t want to miss!
The Nationals Navy Carrier events will
be flown Thursday, Friday, and Saturday,
July 15-17. As usual, the Profile Carrier
events will lead off, with processing for
AMA Profile on Wednesday evening. The
NCS will sponsor Sportsman Profile Carrier
as an unofficial event. Sportsman will be
flown with AMA Profile on Thursday.
Sportsman contestants are encouraged to
process their models Wednesday evening,
although they may be processed on
Thursday on a noninterference basis with
the AMA event.
Class I and Class II will fly on Friday.
Nostalgia Carrier (all three classes), .15
Carrier, and Skyray Carrier will fly on
Saturday. The NCS annual meeting and
awards banquet will be held Friday evening.
We are seeking volunteers to officiate
and support the Carrier demonstration at the
World Championships and the Nationals
Carrier events. Please contact me or Bill
Calkins (317 Snow St., Sugar Grove IL
60554; Tel.: [630] 466-1531; E-mail:
[email protected]) for full details about
any of the Carrier events or to volunteer to
help with the events.
Nostalgia Profile Carrier was flown at the
Northwest Skyraiders Tailhook 2003 event
in Tacoma, Washington, in August. There
were four entries; all flew Nostalgia-period
aircraft, and all but one used loop-scavenged
engines. D. Salter won the event with a Bill
Melton Guardian powered by a SuperTigre
ST-35. Other models included a Super
MOHO, a Midwest Skyraider, and a GS
Bearcat.
Nostalgia was also flown at the
Southwest Regionals in Tucson, Arizona, in
January, but I’m unable to provide details of
that contest because my deadline for this
column is before it takes place. Check the
NCS’s High Low Landings newsletter for
results.
Others who are building Nostalgia
models for this season are Bob Heywood
CONTROL LINE NAVY CARRIER
Dick Perry, 427 Live Oak Ln. NE, Albuquerque NM 87122; E-mail: [email protected]
Dave Dawson entered this MVVS-powered Sniper in the Phoenix AZ contest in
November. It was Dave’s first Carrier contest. The smile says it all!
Loss of a propeller blade can have disastrous consequences! This Profile Guardian
disassembled itself instantaneously in flight.
(Dayton OH) and Jim Dross (Tulsa OK).
I’d appreciate hearing from those of you
who have new models for the 2004 season. I
can always use photographs to include in the
column. You can contact me at the address
in the column header.
I attended the Central Arizona Control
Line Club’s contest in November and had a
wonderful time—with the exception of
witnessing a spectacular in-flight breakup,
probably caused by the loss of a propeller
blade during high speed.
One of the highlights of the contest was
getting to meet Dave Dawson (Burbank
CA). He was competing in his first Carrier
contest, flying a Bill Bischoff Sniper design
in .15 Carrier. Dave has been flying Carrier
with Ron Duly’s encouragement and help,
and judging from Dave’s smile he
apparently had a great time. I’m sure we’ll
be hearing more about him in the future.
Welcome aboard, Dave!
The result of the in-flight breakup I
mentioned is shown in one of the photos.
The model went from 110 mph to pieces,
fluttering to earth in an instant. Fortunately
the largest mass (engine and nose) stayed
attached to the bellcrank, and the inboard
wing, although separated from the fuselage,
stayed on the lines as well, forming an
effective airbrake. The lighter pieces landed
near the point of the breakup.
If you haven’t experienced the loss of a
propeller blade in flight, you don’t want to!
We stress our propellers a great deal during
landings when they often hit the deck. Even
at low throttle, the “sudden stoppage” is
hard on propellers. Nicks and scratches on
the blades are potential initiation points for
cracks, as are contact points from thrust
washers, propeller washers, or spinners if
they touch the blades.
Discard any propeller that is damaged or
that has had a sudden stoppage, even if no
damage is apparent to the eye. I know of no
damage history on the particular propeller I
was using, and it still came apart. If you lose
a propeller blade, there is nothing you can
do but watch.
For a bit of added safety, you should
design models so that the bellcrank mount is
tied to an engine mount; therefore, the
engine will stay in the flight circle during an
accident.
I received a letter from a Carrier modeler
asking if there was a “best” place to put the
tailhook on our models. His problem was a
tail-heavy aircraft, and he wanted to try
moving the hook forward to a point under
the wing to help move the balance point
forward.
There isn’t one answer to the question.
As a general rule, the pivot point for the
tailhook should be near the rear of the
model. That location helps avoid potential
problems of tipping the model’s tail up
when it is arrested, but almost any location
154 MODEL AVIATION
Visit the AMA Education Committee
Web site at www.buildandfly.com.
May 2004 155
can be made to work as long as you are
careful.
When a model’s tailhook catches the
arresting line, physics is the dominating
factor. The faster the model is moving on
landing, the more powerful the forces are
acting on it. During the arrested landing,
the model’s CG tries to continue moving
forward, and the force of the arresting line
acts on the tailhook in the opposite
direction.
No great revelation there, but an oftenignored
factor is the tendency for the end
(hook) of the tailhook, the tailhook pivot
point, and the model’s CG to form a
straight line. You can see this straight line
if you hang the model from the tailhook
with no spring on the tailhook. The hook,
the pivot point, and the CG will line up
vertically.
What that means during the arrested
landing is that a hook pivot that is lower on
the fuselage than the CG will tend to rotate
the model’s tail up to achieve the straightline
alignment. With the pivot nearer the
rear of the fuselage, the tail-up angle to
achieve that straight line is minimal. If the
tailhook pivot is closer to the CG—e.g.,
under the trailing edge of the wing—the
tail-up attitude to achieve the straight line
can be quite pronounced. In the extreme,
the model could be tipped up on its nose,
reducing the landing score.
That’s it for now. See you at the Nats! MA