The Ampeer ON-LINE!
June 2012
The Club Newsletter of the Electric Flyers Only, Inc
AMA Charter 2354
Walled Lake, MI, USA
Editor: Ken Myers

Fly the Future - Fly Electric!

Contest Director: Dave Grife - E-mail: grifesd@yahoo.com or Phone: 517.279.8445
Please e-mail or call with any questions.

     The Flying Field will be open Friday, June 1 for early arrivals
Saturday, June 2, hours are from 9 a.m. 'til 5 p.m.
Sunday, June 5, hours are from 9 a.m. 'til 3 p.m.
Landing Fee is $10 for the weekend.
Directions: Quincy is approximately 4.5 miles east of I-69. Clizbe Road is approximately 1.6 miles east of Quincy. The Flying site is approximately 1.5 miles south of US-12 on the west side of Clizbe Road.

     Saturday, April 7 was a beautiful Michigan spring day with the temperature around 60-deg and light winds.

     The turnout was good at the Midwest RC Society 7 Mile Road flying field. It was a wonderful day of flying spent with great friends.

     The first photo shows some of the "guys" preparing for a day of flying.

     The second photo shows Keith Shaw with his Halberstadt indoor flier, which he flew outside in the early morning, while the winds were down.

     The third photo, well look closely. What kind of transmitter is Keith holding? Yes, it is a single channel featuring one push button; one push for right, two pushes left, three pushes up elevator and quick blip medium speed-full speed-medium speed-off. The new 2.4GHz system is housed in an "old" transmitter case. The up-to-date onboard radio system responds as if it were a compound escapement type, but without having to count the winds of rubber to know how many times the transmitter may be keyed.
     Not only does the 2.4GHz antenna give away the fact that it is a "modern" system masquerading as an old timer, as the original antenna would be very long, but holding the transmitter in one hand would have been very difficult due to the very heavy battery!

     In the May 2012 Ampeer article "Is a 50 a 50?", I suggest a power system for a Canadair 215. David shares his thoughts about that power sytem. KM

Dear Ken,

     Hi, hope your are well and thanks, as always, for the Ampeer.

     Luckily I was asked to do a review for a local magazine onÊan OS motor and selected the OMA-5020- 490 (5053-490, 350g KM) as my "test" motor.
     ItÊproved to be beautifully presented and made. The motor comes with a handy guideÊin the form of a printed sheet with some figures andÊmy tests ran very close to these power figures. (That's very interesting. I have two of the OMA-3820-1200s and an OMA-3825-750 and none of them have been close to the amp draw and watts in numbers supplied by O.S. on their instruction sheet when run with the APC "E" props noted in their tables. I have reviews ready for both of these motors and they will be appearing in upcoming Ampeers. KM) I used APC 'E' props and my guess would be that the 50 sized motors would be over powered for the Canadair unless it is exceedingly heavy. Also prop size would be a controlling factor. I now use "my" O.S. Motors OMA-5020-490 in a Sebart Sukhoi 50 which is around 3kg (6.61386 lb. or 105.8 oz. KM). Just for general flying I use 5SÊon an APC 15x10E. I'm seeing 850 watts in, which is just a handy amount of power for my sport flying. On occasions I go a bit crazy and use 6S on the same APC 15x10E prop. That bounces me up to just shy of 1400 watts in and at about 58 amps. As you can imagine, vertical is not an issue. OS suggests that thrust is 5.4kg in this form.
     My batteries are 40C Fullymax using two 3S 3200mAh in series and they seem to hold very high voltage for about 50% of the flight time without any problem. Certainly there is no apparent power sag.
     As theÊOS motors now give me a fair amount of confidence, I'd probably be looking more at the OMA-3825-750 (3848-750, 190g KM) as a choice for the Canadair. OS suggests that on 4S with a 13x8 the power should be 688 watts in with 3kg thrust at 8600 rpm. (At 14.8v - 4S pack after a short static rundown near the top of the pack - the amp draw would be about 50 with approximately 735 watts in. That is well above the O.S. recommended 40 amps continous. The Kv is actually closer to 800 as measured by Skylar (Christo), 794, and myself, 805.
www.rcgroups.com/forums/showpost.php?p=19807825&postcount=127

RC Groups thread on the O.S. Motors' outrunners.
KM)
     As I said, unless the Canadair is very heavy 1300+ watts in should provide plenty of urge added to which one gets extra efficiency from the twin props.
     I'm using a couple of the Scorpion SII 3026-710s. (3852-710, 205g with measured Kv of about 770 KM) One has been regularly flying an ARF Corsair weighing 7 pounds. Power has been off 4S with an APC 12x6E and all of the usual aerobatics are no problem. I'm mentioning this simply because that Scorpion is somewhat similar to the OS OMA-3825-750.
     I hope this is of interest, although more by gut rather than lab results.

Regards
David Hipperson
Melbourne, Australia

Ken,

     I don't know whether you saw this in the June 2012 edition of Model Airplane News.
     It is an answer to a major safety issue - how to determine the rotation of a brushless motor without having to have a prop attached.
     It certainly needs to be broadcast around.

AJ

     What Arthur was refering to is a tip by C. Robert Gladding of Tavistock, Ontario, Canada. He suggests wrapping a 3" to 4" piece of tape around the motor shaft and sticking the ends together to form a "flag" and then watching the rotation of the tape "flag" when the motor is turned on.
     I've been doing a lot of motor testing recently and wanted to know whether I'd gotten lucky or not while hooking up the three motor leads of the outrunner brushless motor to the electronic speed control (ESC). I used the method recommended by Robert and Arthur, with one modification. I used a marker to put a big black dot on one side of the tape "flag". That made the rotation determination extremely easy. That is a super safety tip!

Hi Ken,

     Thanks for the feedback, and the tip on Jim Young's Meteor. I'll definitely try to find some info on it.

     I'm having a bit of a problem making connections between the motor control wires in the wings of my B-47 model, and the battery leads. ÊThe main problem is there is very little space in the wing where it bolts to the fuselage center keel. ÊI'd like to make the connections in that location (rather than down inside the fuselage where the batteries are) to cut down on the wiring, and to make it a lot easier to connect the batteries after the wings are bolted on. ÊWhat I need are some nifty little Y connectors (rather than wiring harnesses) that have a single (say, +) input, and two + outputs; need the same for the minus side of the battery: ÊI'm using one 5000mAh LiPo pack for each pair of motors (#1 and #6; #3 and #4: etc.) ÊIf you've ever come across any such connectors, and have time to let me know about them, I'd appreciate it.
     I've attached a shot of my model with a sky hook to hold up the RH wing while I try to figure out the connector problem. ÊI'll send you a couple more photos when I get the lead sled assembled for the taxi tests.

Regards,
David Plummer

     At the time David asked about connectors IÕd forgotten about these. I responded a couple of MONTHS later with this reply. KM

Hi David,

     I'd forgotten about these connectors. ÊThey might work to make wiring the B-47 a bit less cumbersome.
     They are by Multiplex and available from Tower Hobbies.

Photos are linked to Tower Hobbies

Hope this helps,
Ken

     The Skymasters are also having a two day meet, June 9 and 10. The electric meet is on June 9 with a Pot Luck dinner at the field followed by night flying. Sunday June 10 will be Open flying with other Skymasters' members. The event starts at 10 a.m. on June 9 and will continue until Midnight. Contact Pete Foss email: petefoss@skymasters.org. For more information: www.skymasters.org/events/flyers/electricfly.pdf

     The weather was kind of "iffy" on Saturday, May 12. The reports were for some moderate wind and the possibility of showers. While the sky was a bit gray and "flat", those in attendance found it a good day for flying.

     Denny Sumner got the chance to maiden his new LoPresti Fury. The plane flew great! Unfortunately, the canopy, the one made at one of the spring EFO meetings, decided to leave the plane. Luckily it had a pair of eyes on it, so it was easily retrieved while Denny continued to fly the canopy-less plane. Flight report, excellent! No bad habits at all.

     A field lunch was served up by Jim Lapham, Rich Sievert and Arthur Deane. It was great.

     There were a few very light sprinkles as lunch was ending, but they did not deter the flying at all, which continued until mid-afternoon. Most of the fliers were home by the time the actual rains came in the late afternoon.
     It was another great day at the flying field!

     Here is sort of an update. Slowly but surely it's coming along. I'm putting an APC 19x10 prop on to start with using two 5S 5000 mAh batteries in series with an ICE HV 80a speed controller and the 160 motor with a 245 Kv. All up weight is going to be 16 lb. (yikes) I think the power will be plenty. My old gasser weighed 15.5 lb.

     Not shown is the battery tray and the batteries. With the tray in place, there is just enough room for the batteries under the speed controller, which is mounted to anÊaluminum plate. When the cowling is in place, air will be channelled across the batteries and speed controller.

     I just got my prop tonight and worked on the center of gravity (CG). I had to add 1 lb. 4 oz of lead at the firewall.
     I will be hooking up the power system to check the current draw, etc., soon. With the 10 cells, the current draw ought to be pretty low.

Hi Ken,

     Last Friday, May 11, was the big day and the Tri-Pacer made a successful flight! You will see it in person at Mid-Am.

Take care,
Don

     RCCD had an ideal day for their electric fly-in this year on May 19. Midwest members Ken Myers and Paul Sockow pitted together and their planes may be seen in the photo. Keith Shaw pitted "just down the way."

     The Radio Control Club of Detroit puts a lot of work into this fly-in, and it is a lot of fun. You might want to add it to your schedule next year.