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sink-me
Radio Control
Radio maneuvered jet scale models! R/C camera planes! Latest scoop on ideas,
gadgets, commercial items by Howard McEntee
Impressive project is R/C scale F-102 above. Work of West Coaster Chuck Ogle,
it is powered by single Dyna-Jet engine. Babcock 3-channel receiver sits in front
cockpit; we see a Multi-Servo linked to rudder (Photo B). Preliminary hookup was
followed by plaster patterns (600 lbs. of em!). All skin is 1/16" thick; wings are
Styrofoam filled. L.G. is full shock type and needs to be; plane will weigh at least
20 lb. ready to fly.
McEntee
Easy to build proportional actuators are always of interest;
see new design (Photo C), the work of Bob Quick (1896 N.W. 36th St, Miami). It uses
ready-wound coils (by Gyro) and an Eclipse magnet. Bob says he can supply latter
for 60¢ plus postage, for those who can't pick them up locally. Magnet is 3/4"
dia. by about 1/2" thick; note poles are on lower ground faces. There are no close-fitted
parts in this unit, yet it has potent power with 6 V. Can be used at lower voltage
for all but largest planes. Only one point to watch: be sure to use brass or other
non-magnetic metal where indicated. Iron for core parts may be taken from old relays,
or discarded auto voltage regulators.
While a bit out of our "amateur" field, Photo D is still R/C.
Shows Radioplane Co. engineer installing camera in RP-71 drone. Normally used for
target practice, this drone makes an ideal low-cost (Yep, it says low cost! Probably
is, though, compared to sending out manned full-sized plane) means of producing
tactical photos of front line areas. Regular Signal Corps K-25 4" x 5" camera is
used; it is tripped in flight by R/C. Drone is regular OQ-19, which has top speed
of 227 mph, and rate of climb of 2300 ft./min.; it can fly for about an hour; at
flight's end is brought down by parachute. While RP-71 is considered a short-range
camera drone, longer range and higher speed craft will probably be tested soon.
Much more peaceful scene is depicted in Photo E, where we see
Bobbie Runge getting ready to send off hubby Paul's R/C airboat. Whole family must
be in-terested in R/C models; we ran a shot of Paul's daughter in a past issue with
another boat.
Ambitious plane is Tri-Pacer (photos F) by Richard S. Kingston (44954 N. Trevor;
Lancaster, Calif.); it took 450 hours! Ship is twice size of Sterling T-P; while
it weighed 27 lbs. originally, this has been pared to 20 lbs. OK Twin engine, loaned
for this job, turns 18/4 Tornado props, furnished by Grish Bros. E.C.E. radio is
used with Cameron escapement; engine control is by means of varying spark ignition
timer. Wing span is 10'; plane is 80" long. At time finished shot was taken the
plane had one flight, entirely successful.
Ever have the guy who was launching your plane flick a toggle
switch to off accidentally, as he gave the final heave? We've seen it happen more
than once, so the simple gadget shown in sketch G is highly recommended. George
Swank suggested it; idea is that it prevents one from knocking switch on unintentionally,
when handling or packing the plane. Good either way! We should say disc should be
about 1 1/2" dia. for normal toggles, and guard would be mounted with upturned edges
running fore and aft, to cut wind resistance.
George, formerly member of the Buffalo Flying Bisons, has moved to 2312 Bellevue
Ave., Syracuse 4, N. Y.; says there is an active club called Sky Knights in Syracuse,
with considerable R/C interest, although group covers all sorts of model plane work.
An advocate of big models, George reports finishing a 25% enlarged version of the
dmeco Aeronca Champ; his version has 70" wingspan, 15 oz. loading, when equipped
with Schmidt reed receiver and three Multi-Servos.
One last Swank suggestion; look up the Grayhill #10C1015 Button Guard. This 25¢
gadget is threaded to take the place of the nut which normally holds a switch in
place.
Photo B - inside story on Chuck Oqle's Dyna-Jet powered Babcock controlled·F-102
job.
Latest - and final - word on the 4th Annual Great Lakes Regional
R/C Meet is that it will be held Aug. 17-19 at Selfridge AFB, about 15 miles north
of Detroit. Rules and score sheets have already been printed, clubs might be interested
in securing copies, since some interesting innovations are planned for this outstanding
R/C event. We covered these new ideas in March R/C Column. Look up data there, with
score sheets you can see just how things will be run. Latter may be had, along with
any other desired info, from Ernie Kratzet (Box 5197, Grosse Pointe 36, Mich.).
One new idea added since our last mention of these rules is the "Bonus Maneuver,"
which can bring as many as 27 additional points to Championship Flight contestants;
anyone of following may be attempted: vertical eight, tail spin (3 turns, and a
real spin - not a spiral dive), 200 ft. knife edge flight (wings of plane vertical),
inverted rectangle, four-point roll, snap roll from stalled condition, whip stall.
There are many more interesting and new ideas covered in the rules and score sheets
that we don't have room for here - get your copies and study them.
We hear through Fred Collins (29 Stewart Ave., Pittsburgh 27,
Pa.) of new club in that area. So new that no name has been selected as yet, but
basic requirement for membership is that prospective member must be active flyer
with workable R/C plane. Contests and getogethers have been planned for coming season;
elections show following officers: Pres., Fred Collins; V.P., Russ Mehring; Sec.-Treas.,
Frank Kneeland. Ten members on roster; interested parties can contact Fred at above
address.
Old timers of LARKS club of Los Angeles were startled when new
member appeared at one of the regular club contests, tied for 5th place in Single
Channel category; startled because this member was only 10 years old, yet handled
his plane like a vet. He is Randy Wagner of Sherman Oaks, probably one of the youngest
active contest flyers in the country. Randy helps with plane building and does all
the flying, while his dad helps out with radio installation; dad also launches,
but from then on Randy is strictly on his own.
Photo C - Quick's proportional actuator.
Another young R/Cer is 14-year-old Mickey Hargrove (2046 S. 10th St., Mayfield,
Ky.) who writes that he has been building models for three years. He has been flying
a Buzzer'd with 465 mc. equipment, says local R/Cers have a fine unused airport
only two miles from town which is only used once in a while by lightplanes. On good
Sundays, as many as seven flyers show up for action. Mickey is now building a Custom
Privateer, in which he hopes to install 3-channel gear.
Interesting use for R/C models is revealed by John A. Birch
(1061 Great North Rd., Pt. Chevalier, Auckland, N.Z.). While he and a group of modelers
were bemoaning the "high cost of modeling," someone suggested offering use of the
models to the local Army Reserve unit for anti-aircraft targets. A test was arranged
with the unit; standard single channel models were flown. This was apparently quite
a success and further tests were arranged for the big brass. We gather that the
40-mm Bofors guns were just sighted, not actually fired, at these tests. About this
time, though, the modelers learned that the government would not authorize payment
for the models, but suggested the boys could fly their planes as AA targets "at
their own expense." That ended the whole deal right there, but valuable experience
was gained, since the group designed a model that was stable, fast, and able to
fly in fairly strong winds without gaining too much altitude. All this was on plain
rudder control, but multi-controls have since been used, with two RF channels. John
says they use the H.M.V. equipment, which has no sensitive relay - last tube feeds
right into a high-resistance actuator - this apparatus has been highly reliable.
We learn from Dale Root (6036 Telegraph Ave., Oakland 9, Calif.)
that heavy rains have turned their flying field into what might be taken for a rice
paddy. Only a few bare spots left, and "spot landing" has become a must. His club,
the East Bay Radio Controllers, awarded 1955 Trophy for Spot Landing to Bob Forbes.
A spot landing contest is held each month with top man getting 30 points; second
place 20, and third, 10. High-point man at end of year gets trophy plus a merchandise
order. A new wrinkle has been added for '56; as soon as a flyer has accumulated
30 points another part of the Precision Pattern must be added to his spot flight,
and this is repeated for each additional 30 points throughout the year. Idea is
to make it easier for the less advanced flyers to compete with the hot pilots. Recent
spell of interference prompted Bob Leninger to build a Monitor, which has turned
out very well. It is quite sensitive, is in a box about the size of a Babcock transmitter,
can be used both for directional work or for "wide angle" reception. Dale is still
flying his old Ascender, says they recently clocked it in level flight at 68 mph;
plane was equipped with Torp .29. His newest version of the Ascender has Torp .35,
and Dale feels it will be a much better stunter, since it will go right through
most maneuvers without any tendency to stall out.
Citizen-Ship Compound Escapement.
He is also working on a smaller version of this mid-wing design, which will have
48" span and 384 sq. in. area. He hopes to keep completed. weight under 3 lbs.,
will use escapements for rudder and elevator, and some sort of wheel brake will
be incorporated. Since our mention a few issues back that he had some drawings of
his Ascender for sale, he has been astonished to receive over three dozen orders,
from Canada to Peru, South America!
CG reed unit (see previous columns).
At meeting in Winston-Salem, the R/C League of North Carolina
members decided to award Life Memberships to a few persons who they felt had done
a lot for R/C. We were pleasantly surprised and duly honored to receive one of these
Honorary Memberships via a letter from Warren Hall (315 S. Church St., Burlington,
N. C.), said card being made out to include our long-suffering wife as well. Many
thanks, RC/NC! Warren notes that the meeting day was blessed with beautiful weather,
and the 27:14 lineup for the flying session was really impressive. Standout at this
session was a tiny 30" span job by Emerson Ford, named "The Squeal," and Warren
says it sure does! A Cub .075 pulls it, and equipment consists of a Port SM-1 receiver,
Bonner Compound escapement, with provision for up elevator. The RC/NC has declared
war on "bootleggers" in their ranks, will not allow anyone to fly hereafter who
cannot show the proper F.C.C. license. Their Annual Memorial Day Meet will be held
on June 1-3 at Lynchburg, Va., where there is a really beautiful flying spot, plus
fine motel and eating facilities. Flying at this event will be by invitation only,
but we gather that any and all are welcome to watch the fun.
Photo D - Front line camera plane is Radioplane drone with radio-controlled equipment.
Photo E - Mrs. Bobbie Runge shows off "YM" airboat built by husband Paul.
Letter from George Trammell (1815 26th St., Gulfport, Miss.)
brings the news that he is abandoning the proportional control ranks, to go in for
a reed outfit. He also mentions acquisition of a hot new Sport Coupe, and heavy
interest in Hi-Fi; says there is little news of models from his area since even
the ukie boys were brought to a halt by bad weather. His last R/C model was a Live
Wire, which was a bit too heavy for a McCoy 9; a Twin Fury .15 was installed and
did a fine job. George mentions a "Bondeeze" wire made by Phelps-Dodge Copper Co.,
which has a thermo-setting coating over the regular insulation. After winding a
coil with this wire you pass a current through it to heat it up to about 125 degrees
C., and when it cools, the coil turns into a solid hard mass; this would be just
the thing for his actuator that was described in our Jan. 1954 issue. A quick dip
in alcohol will also produce a solid hard, coil.
An "Alex Schneider style" Cub has been finished and flown by
Gordon Gabbert (721 S. Austin St., Dallas, Texas), who says it is "just what I ordered."
So much so that he immediately started another exactly like it, so that he won't
have to stop flying for possible repairs during the coming season. The plane weighs
a bit under 6 lbs., which light weight Gordon credits with the fine stunt performance
he has been able to get. 50% elevators also help in rapid maneuvers, which include
everything but rolls - and he has these under study now. He has been doing quite
a bit of inverted flight and says, "Of course when you do that under 200 ft. the
spectators clap and howl with glee but they didn't spend 90 days on the workbench!"
How true this is!
To get enough fuel capacity for his spark ignition Atwood .49, Gordon has been
using a Walker pressure tank feeding a 2 oz. dmeco "clank tank." A needle valve
is fitted to the outlet of the pressure tank, and after the engine starts this valve
is opened and adjusted to about the same fuel flow as that going from the clanker
to the engine. Adjustment is not fussy, since too much fuel will just go out of
the overflow pipe in the clanker. Both tanks are filled with fuel, of course, and
the pressure tank empties first. This setup has been adopted since Gordon found
he could not use a normal pressure' tank and regulator on a 2-speed ignition engine,
without a throttle of some sort.
Photo F - Dick Kingston and Tri-Pacer.
Doings of the South East Virginia R/C Group reach us through
John Worth (Box 9, Hampton, Va.), who says that the huge glider "inherited" from
Bill Sydnor, when he moved north, is nearing completion. This 12 ft. monster will
have an Ectron escapement modified to act as a selector switch, controlling a separate
rudder actuator and elevator servo - and there are contacts left over for any later
controls that might be desired. The Ectron spring-driven Stick Box will be used
as the transmitter controller, while a small electric motor in the glider will keep
the escapement rubber always wound to the desired tension. It's apparent that the
SEV/RCG expects to keep this plane in the air for extended periods!
Like many, other modelers, John is laboring over a dual proportional system that
does not require flapping control surfaces, and has what he feels is the answer.
System gives dual simultaneous control of rudder and elevator, works on two tones,
one for each control. Pulse length is used for actual control, while pulse rate
of each tone allows for trimming the control surfaces. Geared-down motors run the
controls and each has a pot attached, which feeds back to the tube responsible for
that particular control. Sounds most interesting.
Plane is twice size of Sterling kit.
John mentions several other such systems he has seen or heard of, notes that
it shows plenty of progress in the R/C field, since apparently a lot of flyers are
not just taking it for granted that existing control systems are the last word.
At a recent club meeting an oscilloscope was on hand and members were invited to
bring their proportional pulsers, to see how they would show up on this revealing
instrument.
Due to a change by the manufacturer of the tiny dual-section
condenser used in the Grid Dipper, page 48 of Jan. '56 issue YM, this condenser
will not be handled by the source mentioned in the parts list. Of course, many types
of dual 100 mmf. condensers are available, which will do just as well in this circuit
- but they all require a somewhat larger case. Since the small size of the original
Dipper is one reason it is so useful, we tracked down another source for a substitute
condenser of the same size; this one is available from Lafayette Radio (100 6th
Ave., New York 13, N. Y.), is their #MS-261 and costs 95¢. We believe this
same concern can supply all the other parts required for the Dipper as well. The
condenser mentioned does not have two sections of exactly the same capacity, but
we have found it works just as well as the original 100-100 mmf. job, if the larger
section (the one with more plates) is attached to terminals 4 and 5 of the 1AG4.
It has copper-colored trimmers on the bottom, which should be removed, and has a
regular 1/4" dia. shaft, so a knob will be necessary. Tuning range is just about
the same as with the original condenser.
Speaking of the Dipper (any Dipper, for that matter), John R.
Lulay of 1579 Perry St., Columbus, O., asks how to establish a basis for comparison
in checking receivers for sensitivity. Says he has a two-RK61 receiver that will
only work up to about 4 ft. from the Dipper, and wonders if this is too insensitive.
It is very hard to say, since the operational distance depends upon so many factors,
such as: how good the batteries in the Dipper are; the surroundings (distance will
probably be different in a cluttered cellar and out in the open); whether the receiver
is mounted in the plane or just in a haywire setup on the bench (loading is usually
quite different in each case). However, after you have tried a few receivers in
your own shop, you will get a pretty fair idea of sensitivity, especially if you
try the Dipper on receivers that have been flown and are known to be satisfactorily
sensitive. Offhand, though, we would say John's 4 ft. receiver is not sensitive
enough.
Fig. G. - Switch protector from Syracuse.
How to construct a removable antenna for his plane is the problem
of Joe Zaplicki (120 9th St., Passaic, N. J.). One of the best ways we have found
is to use the chuck end from a radio test prod of the sort made for use with phonograph
needles. The metal end is usually threaded and screws into the insulating handle;
these chucks will take about 1/16" diameter wire, and we have never had an antenna
come out of one in about five years of use. 1/16" aluminum welding rod makes a fine
antenna, or you can solder smaller diameter music wire to a piece of hobby shop
1/16" diameter brass tubing. Actual antenna diameter makes little difference. Some
builders use the low-cost phono plugs and jacks for the antenna, the antenna being
soldered to the plug. However, with this arrangement it is necessary to use a rubber
band over hooks soldered to the lower end of the antenna, to hold it in place; don't
fly without some such securing means.
License query comes from 16-year-old Bill McCray (419 Steele
St., Frankfort, Ky.) who says he has purchased a transmitter and receiver, and the
license blank packed with the former states you have to be 18 to get a license.
That's correct, Bill, but what you can do is have the license made out in your father's
name, or the name of some modeler over 18, if you usually fly with him. It is quite
legal for anyone under 18 to operate a transmitter on the Citizen's Band, if the
older licensee is on hand.
"How do you judge pulse rate?" asks John A. Edrington (Route 2, Box 340, Osceola,
Ark.). He purchased a proportional pulser kit and the instructions said it should
be adjusted for 200-300 pulses per minute. 200 PPM is also about 3 PPS (pulses per
second) and you can practically count that speed. Actually, in most cases the exact
pulse rate makes little difference; since some receivers will not pulse too fast,
we feel it is wise to set your pulser as slow as you can, and yet not have the tail
of the plane "wag" back and forth. Some modelers pulse so fast that the rudder can
hardly keep up, but for all practical purposes the control will be just as good
at a much lower rate. (And your linkage and rudder hinges won't get so much wear!)
An R/C Robot is being constructed as an electronics project
by Charles Johnson (426 E. Market St., Xenia, O.) in his college physics class.
He and two fellow students have tackled the Robot, one making the "body," another
the drive machinery, and Charles drew the R/C system. This "monster" will be about
5 ft. high and has a drive motor in each leg. The builders have to be able to start,
stop and reverse the drive motors, individually and together, to get the desired
flexibility of movement. They also wish to light up the eyes, etc. for show, and
a separate radio circuit will be used to enable two-way communication with the Robot;
a licensed ham will handle this part of the system. All this could be done with
existing commercial multi-channel apparatus, but as the builders wanted to do the
whole job themselves, we suggested an adaptation of the model tractor control system
detailed in the Radio Control Handbook, since this model also had two separate drive
motors, and required the same sort of control on these motors.
Commercial Dept. A whole line of new equipment has been announced
by Babcock Radio Engineering, Inc. (Box 3097, Van Nuys, Calif.). They have redesigned
their Compound escapement, the new model being known as the Mark II; the changes
make it practically immune to vibration, and increased magnetic efficiency assures
operation with very heavy rubber and control surface loads. Price will remain at
$7.95. There is now a Babcock Universal Motor Escapement, which has a built-in air
bleed valve; can also be used to actuate clapper valves and other types of motor
speed controls, or even for normal self-neutralizing rudder or elevator control.
Mounting bracket is extended to hold the rubber band needed for motor control use;
price is $8.95. Babcock is entering the R/C plane field with a kit for an attractive
little mid-wing plane called Breezy Jr.; designed by R. E. Schumacher, plane has
42" span, has been test flown for a year and a half, carrying various receivers,
including the Babcock BCR-3. With this receiver, total weight was 28 oz. and the
ship gave good performance with hot .049 engines on glow.
Breezy J r. kit includes lightweight Hillcrest wheels, colored paper, all necessary
hardware, torque rods, etc., costs $6.95. Probably biggest news from Babcock is
new line of 465 mc. apparatus, which will be available for both single and two-channel
use. Featuring audio tone operation, we gather that the equipment is rather light
in weight, since Breezy Jr. weighs only 22 oz. with the 465 mc. receiver. Prices
and further details are not known as yet.
To cut mailing time for customers on both coasts, Ace Radio Control (Box 301,
Higginsville, Mo.) announces the appointment of Ace R/C East (315 S. Church, Burlington,
N. C.) and Ace R/C West (5811 Marconi Ave., Carmichael, Cal.). These two dealers
will be able to offer same-day shipment of anything in the Ace line, and mail orders
should be sent to them, rather than to the Missouri office, by persons located anywhere
near the two coasts. Ace is undertaking a program of redoing instruction sheets,
drawings and illustrations sent out with all kits, so that they will be of maximum
use to the non-expert purchaser.
Ace is able to supply potent 3/4" x 1/4" alnico disc magnets for proportional
actuators, and also will carry the Barco and IEI lines of sub-miniature electrolytic
condensers.
We learn that Control Research (Box 9, Hampton, Va.), which is the oldest concern
involved solely in the sale of R/C parts and equipment, will close down for good,
sometime after March 1. It is possible that a very restricted line of special parts
may be retained after that time, or that other owners will take over the business.
In any case, operation will doubtless be under different name. C.R. will make arrangements
with other R/C suppliers to stock some of the special hard-to-get parts they have
handled, such as the IEI electrolytics ,and alnico discs mentioned above.
New line of rechargeable alkaline batteries is being produced by Gould-National
Batteries Inc., which should be of real interest to R/Cers. Originally intended
for use in a special flashlight, the cells are identical in size with D flashlight
cells, and weigh about 4 1/2 oz. each. Something new in storage cells is that these
Gould Multi-Lite units are completely sealed, so that there will be no leakage,
and no corrosion problems. Needless to say, they will never require addition of
water or other liquid. The D cell has a capacity of 2.5 AH, at a discharge rate
of 0.5 A., and the average voltage on discharge is 1.2 V. Cells are guaranteed for
250 cycles (that is, charges and discharges), will lose only 20% of a full charge
when stored for three months. They may be stored charged, partly charged, or dead;
charging is made easy, since if the current is 0.5 A at the start of the charge,
the cells may be left on charge indefinitely without harm.
Exact prices have so far not beenset, but the D size will probably sell for about
$3.50 per cell; they may be had from Federated Purchaser (1021 Route 22, Mountainside,
N. J.).
A slightly larger cell is sold at present only in the form of a 4-cell battery
which is in a metal case measuring 2 5/8" sq. x 3-13/16" high. This battery is rated
at 4 AH at 0.8 A discharge rate, and weighs 2 lbs. Average discharge voltage is
about 4.8 V. Retail price of this unit has not been set. Special chargers for either
cells or battery may also be, had from Federated Purchaser.
Two new Multi-Servos have been announced by deBolt Model Engineering Co. (Williamsville,
N. Y.), the 3P3N and 3P3NX. Both are intended especially for engine control; the
3P3N is self-indexing and works on 1 1/2 V, is said to be an improvement over the
3P in that there is no time element involved in operation and the new unit has considerably
more power. The 3P3NX operates the same but is fitted with nylon gears and a 3 V.
motor. No prices on these yet.
Dual transistor proportional pulser is offered by Gyro Electronics (325 Canal
St., New York 13, N. Y.); unit can be had in finished form, and in two types. Pulser
for rudder-only use sells for $14.95, while same unit with added rate control costs
$17.95. Both types include two transistors and Sigma 4F relay, will operate on 22
1/2-45 V. Kits for either pulser cost $5 less. The rudder-only pulser running on
22 1/2 V. requires only 1 1/2 ma. current. Useful to the model boatmen, Gyro is
selling 10-position stepping relay with two decks; model wound for 6 or 12 V. use
costs $9.95, while 24 V. unit is $8.95. Gyro carries complete line of Jaico Gem
relays, newest Gem being one with 100 ohm coil, price $4.95.
Custom reworked motors are specialty of Model Motors Service (Main St., Mantua,
N. J.); at present the only new motors they carry are the Fox .19, .29 and .35 sizes,
which sell for from $15.00 to $19.50, depending upon which Fox size and style (Hi-Power
or Hi-Torque series) is desired. The motors come directly to Model Motors Service
from the Fox factory, and the rework on them consists of polishing and cleaning
all inside passages and parts to a degree that the manufacturer couldn't possibly
afford to go. The work results in engines that are, if anything, easier to start,
that have considerably more power and are generally easier to handle. The work is
aimed at improving the overall performance of an engine, not just the top speed
performance, as is the case with racing engine "souping up." M-S Fox engines have
been outstandingly successful in team racing, a field where handling characteristics
are somewhat similar to those required in R/C.
M-S will also modify engines of other makes sent in by modelers; prices are $5.00
for .09 size; $7.50 for .14-.19, $10.00 for .29-.35. Larger engines will be modified
at the .29-.35 price, provided there is no shaft work involved. Results are guaranteed
to be better than the stock engine.
Surplus Item: unused black-crackle finished aluminum case measuring
about 10 x 9 1/2 x 9 1/2" overall with hinged front cover and detachable back cover,
should be fine for transmitter, or toting fuel and other field equipment. Originally
intended as case for BC-221 Freq. Meter, there are some electronic parts in rear
compartment (several voltage regulator tubes, a 160 ohm relay, condensers, etc.)
and a shock mounted base. Advertised by several concerns, lowest price seen is $2.25
each (include another 50¢ or so for postage) at Aaron Electronics (3830 Chene
St., Detroit 7, Mich.).
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