HOST OF THE NEAT FAIR

Dear SEFLI’ers

We have now had two “Night Fly”/ “Family Nights” at the Cal-verton field with great success despite the weather. I want to thank all that have come or contributed to doing the work. We will have one more on August the 8th. Hopefully it will feel more like summer by then. Both nights produced more than 2 dozen members/family members and guests in attendance.

You may not get the printed copy of this in time, but the July contest has been moved up to Saturday July18th, with the rain date of the 19th. This was to allow those going to the Warbird meet at the Bethpage Polo Field on the 25th a chance to attend the contest. The Easy Star contest will be “cut the mile long video tape” from the Magister. Prez Tom will fly the Magister (turkey shoot) model with a full roll of videotape trailing. All Easy Stars in attendance will cut or at least “bump” the tape. 50 points for each cut, 10 points for a “bump”.

The NEAT Fair vendor and pilot sign-ups are accelerating a bit now with almost 90 pre-registered pilots and 20+ ven-dors. I want to remind SEFLI members who have not yet signed up for working, piloting, or the Friday night dinner to do so as soon as their schedule is firmed-up.

See you all at the field or at the meeting!

Prez Tom

Dedicated to the Advancement of Electric Flight

The Newsletter of the Si lent Electric Flyers of Long Is land

President: Tom Hunt (631) 835-5359 tomhunt@optonline.net

Vice President: Jim Reid

Secretary: Alan Ford

Treasurer: Rick Cascella

Newsletter Editor: Jim Perlowsky jimp.sefli@yahoo.com

SEFLI Main Website: www.sefli.org

SEFLI Newsletter: http://www.sefli.org/news.php

SEFLI Current Events: http://www.sefli.org/current.php

SEFLI Web Forum: http://sefli.proboards11.com

NEAT FAIR: www.neatfair.org

For changes in the monthly meeting or contest dates due to weather/conflicts contact Tom Hunt at the above phone or e-mail.

Prez Sez by Tom Hunt July 2009

Prez Sez 1

Watts Up? 2

Night Fly Photos 3

Show n Tell 4

EDF Slow Stick 5

BF-110 Rebuild 6

Contest Report 7

Lipo Discharger 8,9

Schedule of Events 10

Inside this issue:

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Watts Up?

SEFLI Night Fly

Come down for the third 2009 Night Flying Session. We will show up early and enjoy some dinner (pizza and soda), reser-vations are required! Fly as the sun goes down but the real fun begins at dark. Open night flying and a Balloon Pop Contest. A “Ladies Movie” (Chick Flick) will be shown on an outdoor screen along with drinks for the ladies. So rig up a night flying plane and come on down for some one of a kind flying enjoy-ment that should not be missed.

Third Night Flying Session:

Saturday August 8th @ 7:30pm

Wingnutz Field, Calverton

Dinner Head Count: Contact Tom Hunt by Friday August 7h

(Bring chairs for your Night Flying & movie viewing pleasure)

Session Session

Three!Three!

The 2nd Annual Keystone Indoor Electric Fly (KIEF) will be held in Muncy, PA on October 16, 17 & 18, 2009. This 24 hour, around the clock event is held in the largest inflatable sports dome in the USA. Website: http://www.pafunfly.com/ The following link has a complete report on the first KIEF held in October 2008: www.cloud9rc.com/kief The recommended place to stay is the Econo Lodge in Williamsport, PA (8 miles away). $63 a night with breakfast included. Phone is: (570) 326-1501. Travel distance from Hauppauge was about 200 miles, a little over four hour driving time. The micro/indoor seminars formerly held at the NEAT Fair are now going to be given on the Saturday

(Oct. 17) at the KIEF Show. If you enjoy indoor flying, this is the event for you.

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Photos by Jim Perlowsky June Night Fly

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Jim Perlowsky shows an automatic lipo discharger specifically designed for 3S packs

to simplify preparing batteries for storage. Fabrication details of this “Do It Yourself”

discharger can be found in this months newsletter.

Show and Tell by Jim Perlowsky

Prez Tom is picture with the nearly complete re-build of the wing to his massive KMP BF-110 (94” span). The outer wing panels (outboard of the nacelles) are new and are of a balsa sheeted foam core construction. The flaps and ailerons are now closer to scale size and hinge points type and location.

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Bob Erbe's Slow Stick can now sports a WeMoTec micro-fan (50mm) and very cool inlet lip

(with a little help from Prez Tom's favorite plastic making machine). The lip vastly improves

performance over the naked fan (sharp LE lip). Bob can swap out the fan for the prop sys-

tem in a few minutes. Uses a Mamba 5400KV inrunner motor on 3S.

EDF Slow Stick???

An amazing video showing electrics spanking gas...automobiles at the drag strip!

http://www.opb.org/programs/ofg/videos/view/56-Electric-Drag-Racing

A wonderful demonstration of the ability of electric power...

SLAMMIN’ AMPS!

EDF Stick®EDF Stick®EDF Stick®

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An Unfortunate Rebuild (Part 2) by Tom Hunt

Rebuild of the KMP BF-110 continues, as of this writing the wings are complete and can be covered. The new tails are done and will be covered first with a new tech-nique.

The picture to the right shows one of the new flaps under construction. Three “grown” plastic parts make up the hinge-points and also serves as ribs/ templates to shape the flap. The plastic parts were glued to the lower 1/16” balsa. A 1/8” vertical spar/shear web was installed just behind the hinge line. “False” ribs are glued to the lower sheet than sanded to match the three templates in a straight line with a long

sanding T-bar. A 1/16” carbon fiber rod was installed through the pivots points of each plastic piece before assembly was started. The remainder of the LE contour was blocked-up from ¼” sheet; the ailerons were constructed in a similar manner.

The new horizontal tail was mounted to the fuselage in a similar manner to the original, doweled in the front and screwed back. Previously it was retained with a single nylon screw (head exposed) behind the elevator hinge. This time it’s screwed to the fuselage with 2 steel 4-40 socket head cap screws (submerged) just ahead of the elevator hinge line. The aft-most piece of balsa between the two elevators is actually glued permanently to the fuselage.

I am going to take you on a slight “sidebar”. Some time ago, I reviewed the Flying Styro BF-110 kit from Hobby Lobby for Fly-RC. The model has a 44.5” wingspan and is made from vacu-formed Depron. I had an accident with this model too which wiped out the nose and the front of both nacelles. A 2nd model was ordered, that was the one seen in the review. I put the pieces aside thinking one day I would repair it. I decided that I would use this model as a flying paint scheme test bed. I would paint the model

in a flat black “NachtJager” paint scheme and fly the model around to see if I had any trouble with seeing “attitude” of the model. I have painted a number of WW2 mod-els all black before and have not had any trouble.

Pictures are shown of the reconstruction. The nose is mostly blue-foam with the old plastic parts shoved over the top as they were in a number of pieces after the crash. The lower forward parts of the cowls were salvageable, but I had to cut away the tops and make new motor mounting structure. Two “PJS” outrunners that I got in a close-out deal at Hobby Lobby found their way under the hood.

The lower aft section of the nacelle were replaced with blue-foam blocks

and cover with a light glass cloth (belly-whopper). The “scale radiators” were re-moved from the wing to facilitate shaping. Large cracks in the lower wing skin were found under these radiators and repair (good thing too!)

The model was painted with a mixture of gloss black acrylic artist paint a canvas primer called “jesso”. It’s a rather medium gray color and made the gloss black very “flat”. The Balkenkreuz were from an old model kit never built and the staffel codes were hand cut (yes, I still do these kinds of things) from scotch-cal Mylar. The white shark-mouth was hand painted based on pictures I found of the aircraft. The swastikas were made from black and white trim MonoKote.

I had no trouble seeing this model (and orientation) on a bright day, but will try it again on an overcast day, or at low-light late in the day soon. I will try one other variation before I commit to this scheme. It is shown to left. The lower yellow cowls might show up better for top/bottom recognition. Hope-fully next month I will already have started painting!

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June Contest Results

SPORT ELECTRIC SAILPLANE

JUSCHKUS 1274 ROWSOM 1256 REID 1060 HUNT 861

SLOW STICK COMBAT

REID 190 DOWLING 185 HUNT 170 ERBE 155 BRANDSEMA 85 SALVATOR 25

EASY STAR Limbo

Hunt 38 Erbe 16 Juschkus 6 Salvator 5 Reid 2

Cumulative Points after June Contests

SPORT ELECTRIC SAILPLANE

Juschkus 8 Carpenter 3 Reid 3 Rowsom 3 Hunt 1

SLOW STICK COMBAT

Hunt 17 Erbe 14 Dowling 10 Reid 10 Salvator 5 Brandsema 5 Perlowsky 4 Cabana 3 Capobianco 1

EASY STAR

Erbe 11 Hunt 11 Juschkus 9 Carpenter 6 Perlowsky 3 Reid 3 Salvator 2

by Tom Hunt

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Last month I explained the desire to store lipo packs at the proper voltage level. After a day of flying I have a bunch of packs in various states of charge. To use my chargers “Storage Mode’” feature, the packs must be below 3.85Vdc per cell as the CellPro 4S doesn’t have the ability to discharge. Any dis-charging needs to be “automatic” as I don’t want to risk over discharging. I’ve used my CBA II Battery Analyzer to discharge batteries, but doing multiple packs gets tedious. So I got thinking and came up with the MicroScream Lipo Discharger. This version is designed for 3S packs, the bulk of what I typically fly. The MicroScream Lipo Discharger uses automotive 1157 light bulbs as a load to discharge the subject lipo pack. A latching relay circuit applies the light bulb load to the pack, and a monitoring circuit constantly measures the pack voltage and opens the relay when the proper discharge voltage level is reached. Automatic discharging with the press of a button.

Just connect the battery; the alarm will sound…a check that it is functioning. Now press the red START button, the relay closes and the bulbs illuminate. Wait for the bulbs to go out and the alarm will sound indicating a finished pack. The battery does power the discharger but it draws little current at the end of the discharge cycle. So even if left with the alarm continuously sounding it would take a long time to dis-charge your pack to a dangerous level. But you will not be discharging packs unat-tended, so this should never be an issue.

I’ve found that bringing a pack down to 3.5Vdc per cell is a good voltage level. It’s still well above the 3.0Vdc minimum voltage but low enough that my Cell-Pro 4S can charge/balance my packs up to Storage Mode voltage level in short order. I find most of my “used” packs are above but close to 3.5Vdc per cell (loaded) after flying, only rarely do I find a pack lower. Typically a pack only needs a couple of minutes on the discharger; unless it didn’t get flown .

Each 1157 bulb has two filaments; powering both a single bulb draws around 2.5 amps or about 25 watts from a 3S pack. Just parallel more bulbs to increase the load as these are cheap, readily available and dura-ble (about 1000 hour lifetime). I use sockets to make “adjusting the load” a snap by installing or removing bulbs as needed. I fly a lot of 3S 2200 packs. Three bulbs or around 7.5 amps (75 watts) is a good load for these packs. Smaller capacity packs I use one or two bulbs, larger packs I use all four bulbs the dis-charger is designed for.

The project box looks big, but its size is really used to mount the four bulbs with some space, as 100 watts is a fair amount of heat to deal with. The 2

nd alumi-

num cover the project box comes with I used to mount the sockets: it acts both as a heat shield and blocks the light of the bulbs. Checking the “calibration” of your MicroScream Lipo Discharger is simple, just put a wattmeter in the circuit. This will allow you to check the pack loading (adjustable via the number of bulbs used) and confirm the proper voltage discharge level. Preparing packs for storage was never easier!

DIY Automated Lipo Discharger by Jim Perlowsky

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FABRICATION NOTES:

Part numbers on the schematic are Radio Shack and Digi-Key part numbers. The automotive 1157 bulbs I picked up at BulbTown and the sockets I bought on eBay. The control circuitry was fabricated using a Radio Shack prototype board, p/n 276-148, this really simplifies dealing with the small through hole com-ponents. Use heavy gauge wire to interconnect the battery connecter, bulb sockets and relay connections as up to 10 amps could flow through in this loop. Don’t parallel more than 4 bulbs as the relay specified and used is only rated for 10 amps.

A 2S, 4S, or 5S version of this discharger would require design modifications as the battery being dis-charged powers the latching relay circuit for simplicity sake. The 12Vdc relay used in this design will not operate at 8.4Vdc, 16.8Vdc or 21Vdc. An AC self powered version of this discharger would be required along with reconfiguration of the 1157 load bulbs for other cell number configurations. So the design as shown can only function as a 3S discharger. Web addresses for components as follows:

Radio Shack www.radioshack.com

Digi-Key www.digikey.com

BulbTown www.bulbtown.com

eBay www.ebay.com

SEFLI SCHEDULE OF EVENTS

Silents Please Jim Perlowsky, Newsletter Editor 41 Buhl Lane East Northport, NY 11731

July 18 Contest Flying @ Calverton

July 21 General Club Meeting @ Holtsville

July 25 Whitman Flyers Warbird Meet

Aug 8 3rd Night Flying Session @ Calverton

Aug 15 Whitman Flyers Electric Meet

Aug 18 General Club Meeting @ Holtsville

Aug 22 LIARS Electric Fun Fly 2009

Aug 23 Contest Flying @ Calverton

Sept 15 General Club Meeting @ Holtsville

Sept 18-20 NEAT Fair

Oct 11 Whitman Float Fly @ Lake Ronkonkoma

Oct 16-18 KIEF Indoor Electric Fly

A rare sighting of the Field Maintenance Elf, I always wondered how the grass got cut out in Calverton.

Casey has been doing a great job of taking care of the field. In the years I’ve been a member I’ve never seen such a well maintained field. The dragging, lev-eling and routine cutting has paid off, thanks Casey.