Newsletter April 2016

contact – editorTMAC@gmail.com

Nostalgia – Control Line combat is alive and well at the Nationals!

April AGM There was a good turnout at the AGM and it was great to catch up with some familiar faces whom I have not seen at the flying strip recently. President Bill noted the years milestones as:

The year opened with a successful rally at the TECT Park opening.

The TECT site has been approved by the MFNZ Jet SIG. Reciprocal visits made with Rotorua club. The day shelter has proved popular but we need to add a

toilet facility

Membership is now 50+

Election of Officers The following were elected – Bill de Renzy (President), Roger Peddle (Treasurer), John Colville and John Leonard. No other nominations were received. In accordance with the Constitution the elected members will meet outside the AGM to pick names for vacant committee positions. You may get a phone call!

Presentation of Awards. The most improved pilot award was awarded to Matt Riedl The most deserving club member award (the Corkill cup) was awarded to John Leonard for his services in providing training and grounds maintenance.

Fees for next year - These were set as below. You should have received a direct email notice, but either way, fees are due and would be appreciated paid promptly.

Membership Category

TMAC Subscription

NZMAA Affiliation Fee

Total Payable

Junior 20.00 20.00 40.00

Senior 110.00 70.00 180.00

Family 130.00 75.00 205.00

Associate 110.00 N.A. 110.00

Nationals 2016 – Mike Rice’s experience

Last year I attended the 67th “Nats” at Waharoa and entered my Trojan in the Novice Scale category and my Radian for the ALES (altitude limited electric soaring) event. Right from the start I was well outside my comfort zone. As I recall, the first problem was that I had to declare seven manoeuvres with the Trojan on which I would be judged. I could not think of more than about five and doubted my ability to fly them all anyway. I chose take-off, stall and recovery, roll, loop, Immelmann turn, figure of eight and landing. I had a lot of trouble with the figure eight. The geometry of the

required track was much more demanding than my rather rambling 8s up at the Park. At least my landing was O.K!

On the positive side, I learned a lot in a very short time. More than that I was really impressed by how friendly and helpful everyone was, including the judges. Best of all, I took my model home in one piece.

It was a different matter at the Radian event. Under Bill DeRenzy’s tutelage, I made my first flight and was surprised to discover just how high a Radian will go in 30 seconds at full throttle. I closed the throttle and attempted to level out but lost control immediately and my plane descended vertically into the ground from a considerable height, resulting in a banana-shaped fuselage. Surprisingly the wings, motor, ESC and folding propeller assembly survived to fly again at later date. The cause was self-inflicted. After an incident with a bush-lawyer up at the Park which trashed the original servos, I fitted a pair of HXT 960s housed in some balsa wood boxing. It seems that my boxing was not sufficiently robust and, following a few hard knocks whilst practicing spot landings, the elevator servo must have come loose. Newton’s third law took over and when the elevator was subjected to some aerodynamic load it was the servo that moved and not the control surface.

Not an auspicious start, but I resolved to go to the 2016 event rather better prepared. We booked a unit at the Discovery Motor in Masterton well in advance. This offers first class accommodation and could not be faulted. The question then arose: how to get two or three models and our luggage into our small Suzuki. Having discounted a roof box as being ridiculously expensive – about the same cost as hiring a van for a week - I went up to see the people at Stashit Storage Solutions. They sold me a flat pack carton measuring 950x480x280mm for $8. This was not quite big enough for the Radian but after a bit of improvisation with material salvaged from another old storage box, I had a container which just fitted in the back seat of the car and was strong enough to support our suit cases sitting on top. The new box safely housed the Radian, my Tomboy and my indoor model (the latter for the Fun Fly).

We spent the first two or three days around Masterton visiting friends and familiarising ourselves with the various locations where the competitions were to be held – a wise move as it turned out. The MFNZ HQ was located at the Clareville Complex where some of the events such as control-line and indoor were held but most of the events which required more open space were held in paddocks at various local farms.

There was a pilot briefing and barbeque on Wednesday evening, 23 March. There was a real buzz in the air – everyone excitedly renewing old acquaintances and making new ones. It reminded me of the great sense of camaraderie at the previous year’s championships.

I entered two competition classes:

Vintage RC 1/2E Texaco (with my electric Tomboy)

ALES Radian (Class P) with my 3-channel Radian I had a free day on the Thursday and we toured around watching some of the other events – here again this provided some useful clues on what to expect when I had to fly for real the next day, Friday 25 March. The Vintage competition was staged in a huge paddock off Gladstone Road. The event started in light drizzle which cleared later. Forget our beautiful turf at TECT Park! This was a field of close-cropped stubble. I was very glad that I had given Ouida some previous experience in hand launching my Tomboy – any attempt at an off- ground take-off would almost certainly have resulted in a broken model.

The aim (my understanding – and I stand to be corrected) of the competition is to take off and land within 12 minutes, one point being awarded for each second of flight time i.e. 720 points for a 12 minute flight. Points are deducted for each second in excess of 12 minutes. A landing bonus of 20 points is awarded for landing within 15m of the landing spot. You get two flights only.

I recorded a time of 10minutes and 20 seconds for my first flight and landed outside the circle. My second flight was 9 minutes and 2 seconds but I picked up the 20 point landing bonus. Disappointingly for me, several other competitors out-pointed me. Now that I have got the drift of it, I will be doing a lot of practicing up at the Park for next time!

The Radian competition was held in afternoon of Saturday, 26 March on a paddock not far from Clareville. Our time slot was shared with the F5J group (the big expensive gliders with all the bells and whistles). It was quite an education to see the performance of those aircraft.

For the Radian event I was fortunate enough to have as my markers Peter Hancox and Len Drabble. The rules allow a 30 second power-on climb and a total maximum flight time of 7 minutes. The landing spot is at the centre of two

circles, one of seven metres diameter (50 points awarded) and one of fifteen metres (25 points awarded metres in diameter. Three flights are allowed.

I have not kept a record of my times but under Len’s guidance I was fairly close to the target time. My first landing was outside the main circle but I made it on the second flight. On the third and last flight my Radian was creeping in very low towards the big circle when a tuft of stubble reached up and a grabbed the starboard wing and took it out of the air (that’s my story anyway).

I look forward to seeing my score when the results but I think I shall be pretty near the bottom. However the real satisfaction came from taking part and gaining a lot of useful experience. I can’t wait to get into another competition. It was all great fun and, like the Vintage event, everyone was very friendly and supportive.

In conclusion I would like sincerely thank the Headquarters team (notably Jonathan, Des and Peter) for keeping the whole show together and denying themselves the opportunity to get out and fly with the rest of us.

(Editors Note – next years Nationals will revert back to the traditional New Year time slot and will be held at Matamata. – no excuse for not attending!)

Coming Events

9th April RC scale championsips – Waharoa

TMAC Auction, June 12th at Classic Flyers. Sort out what you want to sell, and crack open that piggy bank so you can buy! Watch for notices on how you can assist.

New Club website This is now active and can be seen at www.taurangamodelfly.nz (Now ‘.nz’ rather than ‘.org’). The website includes a number of useful features which may not be self evident.

The website automatically resizes to suit full size computers, tablets and mobile phones.

If using a full size computer, the font size can be adjusted by pressing “control” and using the mouse scroll key. (or equivalent if you use an Apple computer)

On any page, if you click on the words “Tauranga Model Aircraft Club” it will take you back to the home page.

The background is a blueprint drawing of the Wright brothers 1903 “Flyer”.

Useful club documents such as membership application forms, and club rules can be downloaded from the site.

The website is currently still under development. Thanks to Bill, Mike (both), Mark, Neil, and Fraser for being the original crash test dummies. Thanks to Bruce for photos. I seek your feedback, particularly on matters such as typos, syntax, grammar, errors, omissions, broken links, and suggestions / contributions for additional content. Please email me at editorTMAC@gmail.com with your comments, also let me know what browser you are using and if the website runs OK or not for you. (So far tested on Firefox, Chrome, Edge, Safari). Please also let me know if you want your photo removed. Next steps – The website has been registered with major search engines but their web crawlers will not recognize the site until we generate some traffic. Please let all your modeling friends know, and ask them to circulate to their friends. I hope to keep the website updated on a regular basis so that it becomes a first contact to find out what is happening. Please keep me flooded with photos, and news items for both the newsletter and the website. Currently I am particularly looking for details of the early days of the club, from which to build the ‘history’ page.

Understanding electric drive systems – (the 3rd in a series by Bruce Barnard) The first two articles in this series we discussed power requirements and battery specifications and selection. Now we’ll look at choosing a motor. The majority of motors are identified with letters and numbers that, in most cases, indicate the make and/or series, the physical dimensions or size of the motor (body diameter and length or magnet length) and the number of revs per volt unloaded (without propellor) or Kv.

Specifications and data for motors is available from point of purchase and/or online. Electric motors deliver maximum torque (not power) almost instantly. IC engines, particularly glow engines, won’t develop maximum torque until they are revving, not at maximum rpm, but, typically 70%~80% of max rpm. What does this mean? An electric power system of equivalent power to an IC alternative will, in most cases, be able to spin a larger and/or coarser prop and deliver full power at lower rpm. The speed and volume of air being moved by the propellor, of a particular model, and therefore the power required remains the same, but the propellers will be different. We’ve determined, with power comparisons completed in the first of this series, that a 60A motor with a 4 cell LiPO battery (60A x 14.8v = 888w) will provide enough power to get the job done. But, which propellor should we choose and how fast will it spin? Multiply the KV number by the battery voltage to find the number of revs the motor will produce, eg; 14.8v x 810 Kv = 11988 rpm. NB; this is without a propellor and is referred to as ‘unloaded’. If this rpm, derived from the Kv number, is similar to the IC engine’s max torque rpm, then this electric motor should be a good replacement for the IC engine. We’ve been using my model, a Stick S1500, for comparison. It’s powered with an OS 46LA IC engine spinning an APC 11 x 6 prop at 11300rpm (measured on the ground). This equates to approximately 28.7m/s or 103kph. This engine produces 1.18Hp or 885w at 15000rpm The OS OMA-5010-810 (Kv) electric motor, available from Peter Leaver at www.hangerone.co.nz) will spin a 13 x 6.5E prop at 10150rpm (OS supplied data) which equates to approximately 27.5m/s or 99kph. This motor produces 1.2Hp or 924w (16.8v x 55 Amps).** We still need to talk about speed controllers – thats for next month. - Bruce

Andy Avgas Roving Reporter

Fraser’s Bust Have you ever wanted to put yourself in the pilots seat? Now you can. Fraser had a 3D digital scan taken of head and shoulders and then had a pilots bust printed using 3D printing. The pilot figure is hollow and lightweight. The photo shows the pilot figure before it has been cleaned up and airbrushed. Fraser’s next step is to make a silicon mould and then start mass producing little Frasers. Andy thinks both master and model need a little fettling. Rumour has it that little Fraser is the better pilot!

Rumour also has it that Fraser has acquired a large scale project. More details in due course.

Balsa shavings

Runway centerline markers A big thanks to the crew who have braved the jungle and positioned road cones some 50-100m out, to mark the runway centerline. This is a great aid to lining up for a landing.

International Drone racing. This appears to be becoming a major event. World Drone Prix Race has concluded in an epic battle for 1 Million dollars worth of prize money. Over 150 teams from 26 countries competed. It started out with the indoor qualifiers where teams raced to snag one of the top 32 spots and make into the big show on the first of its kind extreme outdoor race track... http://www.rcgroups.com/forums/showthread.php?t=2624532&utm_source=newsletter&utm_medium=email&utm_content=Click%20here%20to%20learn%20more.&utm_campaign=Mar15%2016%20RCG

Big Fraser Little Fraser

Nominal voltage (4 cell) 14.8v x 60A = 888w Fresh off the charger 16.8v x 60A = 1008w. (http://www.hangarone.co.nz/os-52-four-stroke-size-700-watt-motor-oma5010810-p-5463.html)

It’s open to all countries or individuals that wish to qualify. New Zealand has two teams of 5 people going, 5 in the Quad class and 5 in the Flying wing class based on a qualifying event that was run in January this year. Also check out www.droneworlds.com

Correction –Last month’s photo of the tractor mowing the strip should have named the driver as Frank Brown and not Gary Powell. My apologies to both.

Visit to Rotorua Club Mid month we were invited to fly with the Rotorua club. Their site is nestled in a valley, relatively sheltered, and the runway surface is like a billiard table. 11 of our members turned up, some with partners. This included Neil Attwood, Mike Craig, Bill DeRenzy and Heather, Geoff Gates, John Leonard, Dave Marriott, Jim and Sandra Muir, Steve Noyes, Gary Powell, John Quarrie, Mike & Ouida Rice. Much enjoyment was had flying, trading yarns, and admiring the Rotorua mower.

Some flash models ↑ ← including some aeroplanes

Barbecue courtesy of Rotorua Club – thanks guys

They have a control tower ! ↑ Mike, Neil, Bill and Heather →

Professor Flapbracket on working with transparent aluminium

Yes – there is such a thing. Its called Aluminium Oxynitride and it has amazing mechanical properties. This article is about a different sort. Its not the transparent aluminium of Star Trek fame – that hasn’t been invented yet. This is a different material, available from your local supermarket. It is a type of clear PET plastic, often used for making soft drink bottles. In this article I’ll take you through the steps of making a cheap, lightweight, but virtually indestructible cowling for a 72 size 4 stroke motor. The same process can be used for canopies, spats and airscoops etc.

Step 1 – make a buck. Make from multi layers of plywood clamped and glued together and then scraped with a range of tools to get the required shape. Design the buck knowing that you have to remove it from the finished article, so avoid any protrusions or reverse angles, which would prevent the buck being removed. P

Step 2 – find a suitable bottle. This can be a challenge. While drinks are sold in a range of sizes, this project required a 4 litre bottle. I spent a few hours walking the supermarket shelves, measuring bottles! The staff gave me a wide berth.

Step 3 – cut the end off the bottle, and jam the buck in as tight as you can.

It helps to coat the buck with white petroleum jelly (Vaseline) to help get it in place, and also as a release agent. Try to get the spinner ring centered over the neck of the bottle. You’ll see why, soon.

Step 4 – use a hot air gun to shrink the bottle down. I start at the open end, so that as the plastic shrinks it will tighten around the end of the buck and stop it moving backwards. I use a cheapie hot air gun (Ozito) from Bunnings which has 2 main heat settings and a variable air inlet so the temperature can be adjusted. Use it about mid range. Heat the plastic slowly and over a wide area so it has time to heat through and shrink over a large area. If the plastic bubbles, or turns white, you are too hot. If you melt a hole, its also an indication that you may be too hot!. The Vaseline helps the plastic to flow, and also is a good gauge of temperature as it starts to boil at about the required temperature.

(The red colouring is some automotive putty to fix some dings which “just happened”.) If you want to be clever,

you could apply a vacuum to suck the plastic down tight – otherwise it will tend to bridge across any depressions.

Step 5 – cut off the flashing at the end of the bottle so that the buck can be extracted.

Step 6 – remove the buck. This is easier than it looks. Simply make an adapter for your garden hose or air compressor and screw onto the bottle neck. Water is safer. Apply pressure and with a bit of mechanical encouragement, the buck will pop out.

Step 7 - Clean up your cowling Cut any required holes for cooling, exhaust, needle valve etc. If you don’t like the naked look, paint on the inside with a fuel resistant paint. Total weight – 24 grams. You won’t get this light with fiberglass or built up construction.

Links Advances in aeronautics. The NASA Prandl project is looking at ways to reduce drag by 10-30% and improve

airframe efficiency. Learn about proverse yaw, and how this is used by birds flying in formation. http://www.nasa.gov/centers/armstrong/features/Prandtl-D_validating_new_wing_design.html

When you own the airline you can practice formation flying with a spaceship! http://www.chonday.com/Videos/jegalctospc2

Some photos from the Nationals -https://www.flickr.com/photos/93535622@N06/sets/72157664378322563/

That’s all for this month. Fly hard, land soft, and don’t forget your wing bolts.

Dave Marriott

Editor

editorTMAC@gmail.com

15 deg up