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Large Scale Pylon Racing Canbera 2015
#1

I went to my first Large Scale Air race on the weekend and what an experience that was. It was an amazing spectacle to see these large machines compete against each other around the pylon course. It was Awesome to see so many beautifully prepared scale models and it was incredibly exciting to be able to compete with some of the best fliers.

It was the biggest event I’ve ever raced in as far as entries go. Just the sheer number of large scale models was impressive. This was particularly true of the AT6 Texan class in which there was a dozen entries. I think there were 37 entries across all classes with the red ball class being equally as well represented as the Texan's. I could tell just from looking at the entry list it was going to be a sensational weekend.





In the red bull class I really didn't know what to expect, I hadn't had a real good look at an MXSR, which is the go to airframe. I hadn’t been able to study it side by side with my Harmon Rocket. So I was keen to see how they might compare. I'd not had the chance to fly either airframe and only seen an MSXR fly a couple of times a long while ago. I’d gone for the Harmon rocket purely because of lack of choice and I was wondering how it would stack up against the seagull MSXR which dominates the class.



I hadn't even had the opportunity to test fly my machine I was too busy putting the finishing touches on it and making a box for it to go in. So it could safely make the trip to Canberra on the trailer, I was hopeful it would arrive in one piece.



Like most things in the field of aeromodelling this all took much longer than I'd estimated and a week of very long days stretched into rather late nights. It all seemed to merge together into blur of balsa, linkages, wiring, plumbing and checking and double checking various things. By the end of it the midnight oil had almost all been burnt and it was a very tired Ian and yours truly who were cleaning up snow storm of foam from the workshop floor at 2am Friday morning after making the trailer Box.

I was up again at 6am and Friday morning stretched into Friday afternoon before the Harmon Rocket was ready to fly. The engine had never been run in the plane. It had been extensively modified and carefully prepared for racing but only run for a short time on the bench. All that was done some months before, It was an act of faith, there was no time for a test run of the engine in the plane now, let alone time for a test flight

However it was done, finished and ready to fly. It was 2pm Friday afternoon in Sydney and racing was set to start at 9 am Saturday morning 20km south Canberra. The car was hurriedly packed so much so that I forgot my tacho which would have been very handy for tuning the engine. Oh well it would have to be done by ear.

I drove across town to pick up Ian who was to be my caller and traveling companion. Towelly who was unable to attend the event in person had already begun showing his support by sending numerous lewd scandalous and lascivious text messages. Numerous other messages of support continued throughout the weekend and were a constant force that spurned us on to conquer adversity after adversity. Any help at all was going to be more than welcome and we were to need it all!!



We arrived in Canberra late and just in time to pick up the room key. It wasn’t long before we were joined for a beer by other flyers who had ventured up from South of the boarder. This is part of a nation series so competitors come from all over the country to compeet

It was rather late when I retired for the evening but I slept soundly even if only for a few hours.



Next morning I was up early, I made Ian rush his breakfast so we could get out to the field for a test flight in plenty of time before the day of racing began. My mind was far from calm. I do not like last minuet preparations being rushed and I do not like to operate on very little sleep. I hadn’t flown a model of this size for about a year, I’d never seen this field, but my mood was cheerful and I was excited and glad to be there! I had to listen hard to the GPS to find the flying club which was twenty minutes and about a thousand roundabouts away from the motel.



When we arrived at the field, Ian got to straight to work setting up the shade shelter and unpacking the car. Meanwhile I began rigging the plane, we had little time to sight see or look over the field. I checked the radio, did a final pre-flight of the airframe and filled the tank. Ian who had seen that It was almost ready to start came over and held on to the plane. He placed a finger over the exhaust while I jammed my thumb in the carbie, set the throttle open and flipped the prop to prime the engine. I flipped until I felt the cold nitro rich fuel on my thumb then gave 6 more good flicks then closed the throttle to about 1/3. Holding the spinner tightly I connected the glow plug driver, placed two fingers near the root of the prop blade and gave it an enthusiastic flick. It fired furiously and ran for about a second, then fell silent. Ian glanced up. It was hard to read the expression on his face and since he hadn’t released his grip on the plane I flipped it again and this time it burst into life, caught and held revs. I let it warm up for a moment and advanced the throttle to full noise adjusting the mixture to gain peak revs then backed it off a little. The engine howled and screamed like a thousand cats and dogs. Ian was being bombarded by debris. Small sticks, blades of grass and the black nodules left behind by sheep were being whipped up in the slip stream and swept aft in the wake of the Harmon Rockets whirling APC propeller. The engine was certainly putting out some serious power and I could tell by the look in his good eye that Ian was suitably impressed by it all. I tried to set the idle as low as I dared and it seemed to almost tick over slowly enough. Then I shut it down using the switched channel I’d mixed into the throttle with my Tarains. When active It makes the throttle servo close the carbie completely. With a few coughs and splutters the engine shut down.



I carried the plane to the flight line, enquired of the flying rules and was waved on by a course official to the pilots box. I cant remember

who the official I was so nervous. ”Ready for a test flight?” I thought to myself “are you ever ready?”

Ian held the plane, we primed the engine again this time one flick and it exploded into life.

I intensely felt the nervous excitement coupled with adrenalin that only someone who has test flown an model aeroplane can understand. There was a lot invested in this flight.

I let the engine warm up a moment then opened the throttle fully to clear it out and then backed off. I held a little up elevator to keep the tail on the ground, I nodded to Ian he released it I advanced the throttle just to just passed 1/3 and she roared off into the air. I let go of the elevator and she climbed accelerating and flying straight as an arrow. I turned her round and flew back past to check the trims. Thumbs off she held her course scribing a straight line through the sky. Not a single click of trim, I was amazed watching it and almost had to force myself to fly her back again. I checked the rates they seemed perfect, full elevator just made her groove around a turn or two and I hammered her through the course for a few laps just to get the feel of things. Ian was standing next to me calling out where the pylons were and filling the gaps in my spatial awareness. Ian asked how I was for fuel and since I had little idea I thought it best to bring her in. I called “Landing” backed off and let her slow down a little, she was going way too fast so I climbed out again and asked Ian to put in a couple of clicks of throttle trim to lower the idle while went round. I called “Landing” again and lined up further out she was still too hot the Harmon rocket came past the flight line at about 80 Km/h, engine idling fast, at about 3000 rpm. Again I went round opening the throttle for a bit to clear the engine out and as I joined the circuit for a 3rd time. Ian laid in another 4 clicks of down throttle trim. I called “Landing”, a voice from somewhere called back “Are you sure?” I called out “dead stick” just as I turned on to final, the engine had flamed out, She glided in fast, touched down and ran along on the main gear for a while. Ian called “right rudder” then yelled “RIGHT RUDDER” just as I applied it and the plane turned in time to miss the timing lights that had been set up on the edge of the course. I ran out to recover it from the strip with my heart pounding. Now all we had to do was survive two days of racing.



I spent a little time calming down and having a look at the other planes in the our class. To my disappointment the MSXR’s seemed to have much thinner wing sections than the Harmon rocket this meant that they would probably be a fair bit slipperier through the air. My engine had been extensively modified and carefully prepared for racing but I wasn’t confident it would be enough to catch the slicker airframes of the MSXRs. You see extra drag is a real killer. Because you have to cube your power to double your speed any reduction in drag brings with it a very big reward in terms of speed.

Our first race was early on the schedule so for us things got interesting really quickly. But perhaps I should take step back and explain how it all works. Large scale racing is rather different to the FAI style racing that I’ve done with NSW pylon. Firstly the course is very different it’s flown between two poles and uses two cages and two groups of judges for each plane and is flown from outside of the course. The course is also a fair bit longer. Where the NSW Pylon course is a narrow based triangle flown from inside the course with one set of judges at the far end. With large scale racing the heats are much more spaced apart the whole race order circulates continuously whereas the NSW pylon format has the heats alternating so you do four races then have a long break then three races. The large scale heats are started in the air unlike the NSW pylon heats which are started from the ground. With large scale a race starts like this first each plane is started and takes off in turn then is flown past the judges to be identified. In the meantime the other planes mill about waiting for the start. There is a line through the centre of the course, the clock starts at 30 seconds and counts down to a hooter. The idea is to cross the line just as the hooter goes or very shortly after. Cross it early and you get a cut, a cut adds 10% to your time which is effectively another lap. Get three cuts or more and you automatically get a time of 300 seconds for that race. Large scale racing has the planes in the air for a much longer time and you need a heap of fuel enough to fly for about 8 mins with plus some margin. The Harmon rocket has a 24 oz tank which should allow it to fly for 12 mins.



Estimating the start with a plane traveling at not much under 200 km/h is not an easy task and neither is flying around an unfamiliar course with an unfamiliar airplane. But I was having fun the plane seemed fast compared to the rest of the field and I felt like I was keeping up with Jag even swapping the lead with him a couple of times. After the race was over I backed off the throttle and started slowing down and as I turned towards the strip and the engine went dead stick again. It glided in and landed softly but rather long and I had a fair walk to recover the plane. I must have got carried away with all the excitement, that combined with lack of experience in flying this type of course contributed to me getting 3 cuts in that first race. This meant a score of 300......Ouch!!. All was not lost tho’ because when the scores are tallied you do get to drop your worst time. However if you have to drop your first race it’s a bit like like starting off in a tight corner. After that the pressure is really on and you have to try hard not to make any more mistakes.



I did the pre-flight checks topped her up with fuel and went over to look at the score sheet. I wanted to see my raw time, it looked pretty good I felt hadn’t cut by much so reckoned the raw time would be a fair indication of what the plane could do. It was only a second and a half behind Jeremy and I began to feel as tho’ we might have the right tool to do the job. I wasn’t so convinced that I could fly the course well enough to pull off a place but I was now starting to think the plane might be up to it.



In race two something was definitely wrong, plane speed had fallen off noticeably and the engine seemed to be running lean. I pushed on and somehow managed another cut which added 10% to an already slow time. The engine flamed out on approach again and I landed her dead stick. Doing the next pre-flight check I removed the canopy and noticed fuel leaking inside the fuse. There was a split in the fuel tank this probably contributed to the lean run because constant tank pressure is required for consistent fuel air mixture. Fortunately Jeremy had the number of Monaro hobbies in his phone and called them up. They just happened to have a direct replacement for my tank on the shelf. Ian unhooked the trailer as I cleared the way for the car to get out and I rushed off on the 30k round trip to get another fuel tank. While I was gone Ian did a Sterling job of cleaning up the spilt fuel inside the fuse and I arrived back just in time to fit the new tank fill it with fuel and head off to the start line for the next race.



The wind had been building while I was gone and it was a rather stressed pilot that flew the model in lumpy air past the judges for Identification before the start of the next race. Ian was on the ball, warning me of changes in the wind and pointing out the best way to land. I had started first and gained a lot of height milling around waiting for the clock to start. Consequently the plane wasn’t in a good position for the start and in an attempt to get across the line in a timely fashion I recklessly dove the poor machine under full power at the start line from about 250ft. You’ve got to remember this is a 5kg plus model with a very powerful engine and a steeply pitched prop. It was certainly not as good an idea as I thought it to be at the time. The race went well, my time was good, the engine had come back to it’s former vigour but as I slowed up to land it died and once again I had to land dead stick.



This engine was acting like an on and off switch although it produced massive power at full revs it didn’t want to idle, I think it was probably because I set the low speed mixture using 4:1 methanol and caster fuel and I was now running nitro and cool power with a little methanol thrown in. I would have to remove the cowl to adjust it again but with the other problems I just didn’t get a window of time in which to do this. Ian was also calling for and helping Rod Green so I couldn’t monopolise all of his time. Tuning an engine in a big plane is a two man job if you don’t have starting posts and I had forgot to bring mine in the rush to get ready.



When I recovered the plane from the strip I noticed there was something loose inside. My landing had been soft enough but long once again. On the way back to pits I could see a screw rolling around inside the canopy. “How did that get there? Where did it come from?” I thought. Removing the canopy I could see straight away that there was a screw missing from the elevator control horn it was lucky that the control horn had stayed on the spline or things would have rapidly taken a turn for the worst. I began checking all the linkages as I had done in previous pre-flight checks and when I got to the back end I found the tail plane loose, two elevator hinges busted out and the tailplane spar was broken. I was cursing my foolishness at diving it for the line as I’m sure it fluttered and became damaged during that manoeuvre. We hadn’t missed a race ‘till now despite having troubles but there was no way I could repair this before the next race. There were 4 races set for Saturday and three for Sunday missing any of the remaining races after our less than brilliant start would certainly mean a good chance of getting the wooden spoon. But the plane had landed safely despite the damage and the control horn had stayed on despite losing its retaining screw. As we began counting our lucky breaks the all ready blustery weather began to take a turn for the worst and round 4 was cancelled for day. Now If the tail plane could be repaired we would still be in with a chance for a place tho’ for that to happen we were now relying on others to make mistakes yet it’s never over until it’s over.



We hurriedly packed up the plane and gear away before the heavens opened up and Ian removed the fabric from the shade shelter which now, because of the wind, was threatening to take to the sky for a lap or two of its own. We drove through the storm to Bunnings to look for something to use as a replacement tailplane spar. After searching their entire stock including towel racks spray pack hand pieces and every item that contained a piece of aluminium tube. We drew a blank. We headed back to the club house for a roast dinner which was very nice. Blair who’s house Jeremy and Tony were staying at invited us back to have a look and see if he had some spar material we might use to repair the Harman Rocket’s tail.



Blair had a lovely neat, well equipped work shop and a good stock of arrow shafts and other materials. Jeremy had some 5 min epoxy and zap and together Ian, Jeremy, Blair and I manufactured a new spar, repaired the broken hinges and internal damage to the tail plane and sometime short of midnight Saturday night she was once again ready and back in flying order.

Ian and I returned, trailer in tow, to the motel.



Sunday dawned damp and overcast but calm and not raining. We got a decent breakfast and headed for the field, we set up and got ready for business again. I did another pre-flight check just to make sure all was good fuelled the plane and we headed out to the flight line. This was a brilliant race the Harmon rocket was flying superbly the whole group was flying fast and 4 large models rushed the pylons together lap after lap it was exhilarating and dangerious so much so that Byron was stirred into song and burst out with the very applicable Vargner’s ryde of the Valkyries which went for about the last third of the race. It was a golden moment and one I shall always remember!! As the others taxied their planes up to the pilot area my engine went dead stick and I glided the last half of the circuit and landed in the middle of the strip. This time I didn’t have to walk as far



In the next race there was a timing error something with the lights and Ian demanded I be given a re-run. The re-run was granted and we continued to do some pretty fast times for the rest of the day. The engine started first flick on every occasion except for once when I forgot to prime it properly and Byron in an act of superb sportsmanship stepped in and choked the carbie while I was spinning it over with the electric starter. His plane was already warming up on the ground. My engine continued to scream at full throttle and continued to refuse to run under 3000 rpm and every landing was a deadstick.



by the end of the day we had acquitted ourselves well, taking 6th place right in the middle of the field despite facing adversity at every turn on Saturday we managed to finish every race and had the slow time we got from the lean run and the split tank in the second heat made the average of the other 4 times we would have taken second place.



It was an inspiring weekend one I’ll never forget !! I can certainly recommend going to one of these events even if it’s just for a look

The transport Box for the trailer

   

some of the large scale race planes

   

   

damage to the Harmon Rockets tail

   

The score card for Red bull class

the score is worked out by taking the raw time including any cuts and subtracting it from 300. That way the person with the highest score wins

   

“The knack of flying is learning how to throw your machine at the ground and miss.”

"When once you have tasted flight, you will forever walk the earth with your thoughts turned skyward, for there you have been, and there you will always long to return."  ~Leonardo Da Vinci
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#2

Awesome weekend. My first taste of large scale too - albeit from the timing position on Saturday and from the starter's line on Sunday.

Bit over 20 points would have had you in 2nd, and 40 more again to grab first - you'll close that gap no problem next time out.

Nice job Macgyver'ing up a new spar on Saturday night mate. Was strange to be at a pylon event and (between running around helping out both days and heading off to family on Saturday evening) barely getting the chance to speak with you Jason!

<table width="100%" border="0"><tr>
<td>
<span title="No longer arboreally challenged!">Parkzone Stinson SR-10 </span>
Extra-300S EPP
<del>F-18 Blue Angels 64mm EDF</del>
<span title="Why won't it die?!">HK Mini Cessna EPO</span>
Spektrum DX6i - Mode 1</td>
<td valign=top>
Parkzone T-28 Ultra Micro
E-Flite UMX BEAST
SRL Index
CloudsFly / AXN Floater
"2x6" basla/ply kit built glider
SBach 1000mm</td>
<td valign=top>
Skyartec Cessna 182 (small UAV)
UAV-168 (bigger UAV)
<span title="2nd-hand; rebuild on-hold">"BigBoy" Hugin (biggest UAV)</span>
<span title="For invading small countries">X-8 flying wing</span></td>
</tr></table>
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#3

Very Enjoyable reading Jason, well Done considering all the hicups you had with the Plane, for sure you will do very well next time, arrows are a great piece for plane building. Was the the tank split from the pressure or split from get go ?

Steve Biggrin

What Do You Mean Theres a Throttle Curve ?, Its Either all the way up or all the way down Tongue_smile
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#4

(22-10-2015, 05:41 AM)samste Wrote:  Very Enjoyable reading Jason, well Done considering all the hicups you had with the Plane, for sure you will do very well next time, arrows are a great piece for plane building. Was the the tank split from the pressure or split from get go ?

Steve Biggrin

Thanks Steve!!
I think the tank had a manufacturing fault the leak was right in th corner
I don't think it was leaking at the start because I should have picked it up in the preflight check. I checked everything every flight and didn't notice it earlier
The tank is pressurised by the engine while it's running so it's very possible it let go after I started it for the second race

You gotta love arrow shafts!!

I missed not have a good Yarn Claudio It was such a busy two days we'll have to take the x-8s for a fly one day out at Vinyard and catch up?

“The knack of flying is learning how to throw your machine at the ground and miss.”

"When once you have tasted flight, you will forever walk the earth with your thoughts turned skyward, for there you have been, and there you will always long to return."  ~Leonardo Da Vinci
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#5

Nice post Jason. Interesting reading.

FrSky Q X7 Mode 2, Turnigy 9XR Pro and Evolution. Multirotors, planes plus a couple of heli's. Too many to list.

Aaaaand if the wife is reading this: "The club made me buy these planes, I had no part in it, honestly!"
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#6

http://www.naas.org.au/Large%20Scale%20A...0at%20NAAS

Thanks symo

Heres a whole bunch of pics from the NAAS web site
It was tge NAAS club tgat hosted the event

Some great photots here?

“The knack of flying is learning how to throw your machine at the ground and miss.”

"When once you have tasted flight, you will forever walk the earth with your thoughts turned skyward, for there you have been, and there you will always long to return."  ~Leonardo Da Vinci
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#7

The usual dead stick landing approach
Tha paint on the prop is for balance. These APC props are actually pretty good

   

this is where I'd like to be in front of the MSXR's Wink

   

“The knack of flying is learning how to throw your machine at the ground and miss.”

"When once you have tasted flight, you will forever walk the earth with your thoughts turned skyward, for there you have been, and there you will always long to return."  ~Leonardo Da Vinci
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