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Sig Kadet Trainer Jr.
(During the summer, there was a question about how to convert a
Sig Kadet Trainer Jr. to epower on the eflight list. I felt this was worth sharing, since it does show that not ALL glow
planes make a worthy conversion to epower. Here is what was asked for. KM)
I would be grateful for suggestions on the type of motor and batteries to
use for the Sig Kadet Trainer Jr., as I intend to convert this plane, which is in the process of being assembled to electric.
48 inch wingspan
430 square inch area
Dave Shewning Sr. recommended: Build it light and it would be perfect for
an 8 to 10 cell geared system. Speed 500 or better, quality equivalent 2000 mAh cells or better. Keep the weight below 60
ounces max.
I agreed with Dave, but... I had a chance to get the glow information on
this plane. The airframe is a BRICK! From the glow statistics with a .15 glow, they say 3.75 pounds. That's 60 ounces,
minus a standard 3-channel radio (9.5 oz.) and Glow .15w/muffler & tank (7.5 oz.) that leaves a finished airframe
weight of 43 oz.! That is a whale for this size plane.
Ideally, an electric trainer type plane of this size should only have and
all-up weight (AUW) of 50 ounces with the finished airframe weighing between 17.5 and 18 ounces. I suggested that the
builder look carefully for some weight reductions such as; Converting it to a tail-dragger, replacing the heavy landing gear with
5/32" diameter wire and "Lite" wheels, reducing as much plywood as possible, looking carefully at the design
to see what could be eliminated in the way of balsa, the use a "light" covering and any other "diet" plans.
I suggested the use of a Speed 500 #1789 and MFA belt drive, 8 RC2400
or Panasonic 3000 NiMH, 9x6 regular Master Airscrew prop and a radio system with BEC weighing about 5.5 oz, that leaves
22 oz. for the finished airframe.
But without redesigning the whole airframe, this is probably impossible.
For a better chance of success, I suggested the use of the same motor and belt-drive but with 9 cells and a 9x7 regular Master
Airscrew prop. That gives a possible AUW (all up weight) of about 62 ounces, not too bad. My Eaglet 50, which was about the
same size, weighed 64 ounces with 10 Sanyo RC-1700, Magnetic Mayhem & Modelair-Tech belt-drive, and means the
airframe can weigh 31 oz. or there about, a much more realistic figure.
Again, this demonstrates that not ALL glow kits make for good or easy
conversions to electric power. Choose your planes wisely. Remember that to get an idea of what your electric project will
weigh, when converting from a known glow kit, subtract the glow power system weight and radio weight to get the finished
airframe weight. A "typical" electric powered finished airframe is about 35% of the total weight of a project this
size. To get a reasonable guestimate on the finished weight of the project, just multiply the finished airframe weight by 2.86.
That will give you the approximate AUW. This will also allow you to guestimate the total weight of your power system. Divide
the AUW by 2 and that is the approximate weight of your power system.
Return to "What's In This Issue?"
Eclectic Electric Essentials
Azarr has some unique and useful items at his Eclectic Electric Essentials site;
www.azarr.com. Here you’ll find; Anderson Power Poles, APC Props (Folders, S400,
Slow Fly and "E" Series), Square Motor Mounts, Round Motor Mounts, Control Horns, Screws, Jerry L. Smith's Outlaw Delta,
ModelAirTech drives, DJ Aerotech, Anderson Crimper and Portable Soldering Irons.
Return to "What's In This Issue?"
Maybe not a record, but certainly a challenge!
Tom Hunt with the X-Sounder at a SEFLI meeting. Photo from SEFLI Web site.
(I’m sure that to some of you, this is old news, as by now it will have been
reported in the regular modeling press, but some of you may have missed it. This is from Tom’s original post to the
Eflight list. KM)
In the early morning of July 7th, aviation history was again made on Long Island. An
all electric powered, radio controlled seaplane made a non-stop crossing of Long Island Sound from Bridgeport, Ct to Port
Jefferson, Long Island, NY, a distance of approximately 16 miles (CT shore to boat ramp deep in PJ harbor).
The Silent Electric Flyers of Long Island took up the task some 6 months ago of
designing, building, and test flying a vehicle capable of making the journey.
Approximately 15 members were directly involved. A full all-telling article will be
presented in MAN later this year. Just as a teaser though....some basic facts.
100" wingspan
1500 sq.in. wing area
7 lb. RTF
Aveox 1415-4y motor (direct drive)
Schulze 55bo sensorless controller
APC Electric 14 x 7 prop cut down to 12.5"
14 Panasonic 3000 NiMH
Super Circuits PC87 miniature video camera and Tx
4-1000 mAh NiMH RX pack
8-600 mAh NiMH Video power
Take off motor current: 24 amps
In-flight cruise current/voltage: 3.5A/15.5v (measured by a home made down-link watt-meter)
Cruise speed: approximately 20 MPH
Flight time: approximately 45 minutes.
(Note: NO NiCdS anywhere on board! even the TX had and 8-cell 1600 NiMH pack!)
Bob Erbe (15 ft. Boston Whaler boat captain), Mario DiDiego (communications officer, ship to shore radio and video) and
myself, Tom Hunt (Seaplane Pilot) arose at 3 a.m. to fight off the fisherman at the boat ramp in Port Jeff to get a good spot.
Clyde Geist (VP SEFLI) and Henry Prew (Pres SEFLI) were high above the sound in Clyde's Cessna 172 taking air-to-sea
pictures.
The model took off just inside the Port Jeff jetty into a slight headwind
(approximately 4 MPH) and 45 minutes later landed less than 1/2 mile from the CT shore in 3 ft. of water. The headwind (20%
of flight speed) was too much to overcome.
Undaunted, The cross-sound crew swapped out the motor battery for a fresh pack.
The model took off towards the CT coast (approximately 200 yards away), crossed the shore and turned SE back towards PJ,
LI.
Now, with a 4 MPH tailwind, not only did the model cross to the LI shore easily, but
the model was then flown into the harbor, past an exiting destroyer tender and x-sound ferry, quietly sneaking up to the docks at
the far south end of the harbor and then made 2 victory laps before it landed less than 50 yards from the boat ramp.
The total distance traveled shown on the GPS was 15.7 MI. Digital still photography
was taken from the chase boat, as well as sporadic 8 mm video. Video from the camera onboard the model was recorded on the
chase boat also.
Now.... if you thought this was easy.... think about it.... get a 7 lb. seaplane off the
water.... cruise on less than 60 watts (the painful output of one speed 400 motor!) continuously for 45 minutes and do it at 20
MPH (not terribly fast even for a model!) Do it without gliding, or thermal assist! Next? a round trip? feasible? yes, but it may
take a new model. but most of all? WE HAD FUN!! (and we did something no one had ever done before!) Regards, Tom Hunt
X-Sounder: Some pictures and info is up. Go to:
http://www.nyblimp.com/SEFLI.htm and follow the links to see everything.
Return to "What's In This Issue?"
Page Aviation Super Cub
From: John R. Houvener, 1105 Ashman St., Midland, MI 48640-5469
Ken,
I finished the Super Cub and now have four test flights on it. Using the information
that you sent me with your spreadsheet, everything came out beautifully, Super Cub-like flights and no trim problems.
However, I did come out 12 oz. over the 8 lbs. that I was shooting for, but no
problem on power using the deWalt 14.4 and 3.06:1 Modelair-Tech belt drive. The deWalt with belt drive is quite heavy at 21.8
oz, plus I stuffed in a 1/4 scale pilot at another 3 to 4 oz. I probably could hit 8 lb. or a bit less with a brushless motor system. But,
it doesn’t need to be less with the power of the deWalt and the long wing at 80&qot; and 940 sq.in.
The ads in MAN and RCM stated 6 1/4 lb. with a .40 two stroke to a .70 4-stroke. I
thought "WOW" this is pretty light even for a glow engine version for a model that big. I called Mr. Adrian Page
(902-538-7395) and discovered that he is in Nova Scotia, Canada. He stated that to his knowledge, nobody had electrified the
kit yet, so I ordered the kit. This is a super kit. It has laser cutting and beautiful wood. Now, the fuselage sides and some of the
bulkheads are lite ply, but this is the best lite ply I have ever seen. It is light, but not the wimpy stuff that we see in most kits.
Never the less, (and my apology’s to Mr. Page) I replaced the fuselage sides and
doublers with medium hard 1/8" balsa. When I weighed the pieces of each, I only saved 5 oz. This doesn’t mean squat on
a plane of this size. I went to a lot of extra work for nothing.
If you build this kit, and you should if you are a cub fan, stick with the lite ply as it
comes in the kit. With the deWalt power system, this plane will fly well even if it comes out at 10 lb.
I ordered documentation and colored views of Super Cub. Some Super Cubs had
flaps and wheel pants and also used floats with different engines.
Mr. Page used flaps on his personal super cub in order to keep it from floating
across the field, but he was only 6 1/4 lb. with a .56 four-stroke engine.
I put in the flaps as per the documentation and plans, but at 8 lb. and 12 oz. I don’t
need them, and we do not have a large field at our Midland R/C Modelers Club field. You could knock off 4 oz. and two servos
by taping in panel lines for flaps.
Here are the Specs:
The Page Aviation Super Cub
Wing Span: 80” (I.M.A.A. legal at 1/5 scale)
Wing Area: 940 sq.in. - 6.52 sq.ft.
Final weight: 8 lb.12 oz. (140 oz.)
Wing loading: 21.5 oz./sq.ft.
Motor- DeWalt 14.4 V with MAT-H-1000 belt drive (3.06:1)
Battery: 18 RC-2400
ESC: FMA 50 Amp 8-24 cell
| Prop | Amps (at take-off) | RPM | Watts | Watts/lb. in | Watts/lb. out |
| 13x10 APC-E | 30 | 6600 | 600 | 68.5 | 48 |
| 14x8 CAM | 31 | 6700 | 640 | 73 | 51 |
Note: The APC-E props are really thin. If you tickle the runway, good-bye prop. (beware)
Flight characteristics are about the same with either prop. It’s a little faster with the
13x10. I don’t have to hold up elevator on either taxi or take-off. When the tail comes up, off she goes in about 60 to 70 feet.
Flight time with either prop is 8 to 11 minutes, with a few loops and hammerheads thrown in. I will try a 13x9 in near future.
I am just as pleased with this kit and flying qualities as I ever was with the LT-25. I
will rate the kit at 4 1/2 stars, and the finished airplane for flying quality at 4 1/2 stars.
Very truly yours,
John R. Houvener, Sr.
PS You got me again on formulas. Up to date I figure that I have solved all your past formulas. I even bought a new
calculator to do so. However in last Ampeer NL your formula on back figuring wing area (Wt./fllght factor *144)3/4,
What function is 3/4?
(In words: weight divided by flight factor times 144 raised to the 3 over 4 power. The ¾ power can also be
expressed as 0.75, therefore it would be weight divided by flight factor times 144 raised to the 0.075. Hope that helps.
KM)
Return to "What's In This Issue?"
To Reach Ken Myers, you can land mail to the address at the top of the page. My E-mail
address is:
KMyersEFO@aol.com
EFO WEBsite: http://members.aol.com/KMyersEFO/
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