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Scratch Building a 72" Top Flight Contender

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Old 02-14-2015, 09:28 AM
  #26  
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Originally Posted by Instructor View Post
Hi DBD1,

Check out this link for plastic canopies. They have all sizes and shapes....

http://parkflyerplastics.com/cart/

Larry/Instructor
Thanks!
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Old 02-14-2015, 12:14 PM
  #27  
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Rich is JEALOUS of that incredible workshop!
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Old 02-14-2015, 03:10 PM
  #28  
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Hey Rich,

First, welcome to RC Universe, since that was only your second post I'm honored that you posted it in the Scratch Building forum. Always glad to have more scratch builders around.

Second, check out my Blog. I posted photos of my workshop in a couple of blogs. It's a very small area in my woodworking shop. Retired planes hanging from the ceiling do bring back a lot of good memories.


Next, we had a nice day without a lot of wind, so I took the Contender out to the field for some breaking in and a first flight. Darn ASP did not want to play. Only way it would keep running was to turn the needle valve so far that it was about to fall out. The Contender was tossed back into the van, and I flew a few flights with another plane, so all was not lost.

Back in the shop, pulled the engine so I could pull the carb. Took everything apart, reset everything according to the instructions, put it on my test stand, and it fired instantly and ran perfectly. It even had a good idle after just two tanks of fuel through it. Murphy's Law wins again. There is nothing wrong with engine or the carburetor. All I can guess is it was not preset correctly before leaving the factory, or else it had a chunk of dirt or shavings in it.

Will continue to break it in before installing it back in the plane and heading back to the field for that first test flight. We just don't get that many fairly calm days in SW New Mexico in the spring - well, it's almost spring here, but hope to fly it soon. I have a feeling it is going to be great!
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Old 02-15-2015, 06:09 AM
  #29  
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Originally Posted by tomclark View Post
Hey ET,

To me, a plans builder is someone who copies the build exactly as it is on the plans, changing almost nothing. I read in the threads how many builders pay someone to cut a kit for them even. Wonder why? A scratch builder takes a small plan, and builds it what ever size he wants, bigger or smaller, ignoring the construction detail on the plans and builds it his own way. My definition anyway…

.
Tom, thanks for the reply. I wll go with your definition, I am a scratch builder. That plans book looks very interesting. Good for the library. I hope all goes well with the engine and you get some good flight time in. ET.
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Old 02-15-2015, 10:05 AM
  #30  
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A new installation is prone to a sliver of silicone or dirt clogging the mixture needle. Failing to richen with needle far out is an indicator.

I like your definitions between a plan and scratch builder.... they seem to fit.

Good job on the Contender... and best for many more future builds.
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Old 02-16-2015, 06:49 AM
  #31  
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Originally Posted by AA5BY View Post
A new installation is prone to a sliver of silicone or dirt clogging the mixture needle. Failing to richen with needle far out is an indicator.
I like your definitions between a plan and scratch builder.... they seem to fit.

Good job on the Contender... and best for many more future builds.
What did you mean by "silicone"? Lost me there.

I took the the carb off and tore it down. Couldn't see any dirt. Put it back together, set up the test stand (first time in years) and the darn thing fired right up and ran perfectly. Put 16 oz of fuel through it, breaking it in like an old article I have says to do it. Run it for two minutes at a rich two cycle setting, turn it off and let it cool down, repeat 5 times. Then run it for 5 minute bursts at a still slightly rich 2 cycle (it is an ABC engine) and repeat until it is running good.

Hope you don't let my bad experience first time at the field turn you off on ASP engines. My two Magnums run great and have been trouble free. This thing is turning a 15/6 prop at 10,500 and it's not leaned out yet. Cost new was $89. Compare that to other engines.

It idles beautifully, so mounted it back in the Contender. Looks like today and tomorrow forecast windy, but Wed looks great, so will try first flight then.

This whole breaking in on the test stand worked so well that I put a Supertiger 2300 (1.41 cu. In.) back on the test stand. It never did seem to break in right, yet I read on the web that many fliers think it is a great engine. If it breaks in ok this time, it will go in my next scratch build, a new two-meter Kaos I am drawing up today for pattern type flying. Going to have a little fun with a thinner airfoil and higher and longer fuselage - both 78" and weight around 8 lbs. May not win any contests, since I don't enter them, but it will be a barrel of fun and fly great…

By the way, for those who think big glow engines use too much fuel, I usually take two planes to the field, fly four or five flights, and almost never burn more than 16 oz of fuel. When you don't fly wide open for the whole flight, and use the throttle like it was meant to be used, these engines don't drink a lot. They are light, cheap, and reliable when tuned right.
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Old 02-16-2015, 10:14 AM
  #32  
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Fuel lines for glow are made of silicone. During a new installation when sliding fuel line onto brass tubing, sometimes a sliver of the silicone is shaved off and ultimately clogs at the needle valve and is very hard to detect visually. Such a condition should be suspected when opening the needle valve will not richen the engine.

Very often, simply taking the needle out and pressuring the vent line momentarily will clear any debris.

While I've taken a tack towards gas, there is nothing wrong with glow engines, and continue to run several. Glow use at our field however, has greatly declined in use. The once yearly purchase of a drum of club fuel, has ended. The last drum was purchased three years or more ago, and still has a good bit in it with little demand the last year.
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Old 02-16-2015, 11:25 AM
  #33  
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Originally Posted by tomclark View Post
Put 16 oz of fuel through it, breaking it in like an old article I have says to do it. Run it for two minutes at a rich two cycle setting, turn it off and let it cool down, repeat 5 times. Then run it for 5 minute bursts at a still slightly rich 2 cycle (it is an ABC engine) and repeat until it is running good.
Is this the article you read? http://www.mecoa.com/faq/breakin/breakin_abc.htm
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Old 02-16-2015, 03:56 PM
  #34  
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when I was just getting started I used to daydream about having that book. I wish I would have saved the money to buy it. Of course, back then I always thought "someday", never considering there'd be a time when it wouldn't be available.

Austin
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Old 02-16-2015, 04:20 PM
  #35  
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I have a huge notebook filled with reference articles I have clipped out of lots of mags over the years. This one does not say where it came from , and the back side is filled with arf ads and no mag info either. I usually just break engines in while flying, unless there is some problem like this one had. Method does seem to work without causing noticeable problems.
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Old 02-19-2015, 11:34 AM
  #36  
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My apologies to all you folks that live in the great frozen north, but today we had a perfect flying day. 70 degrees and a light breeze right down the runway, so it was finally time for the first flight. All went very well and was much as expected. The ASP was on it's best behavior and ran perfectly. The Contender, to use an old term, "Flies like it is on rails." Round loops and very axial rolls are extremely easy. Inverted flight just takes a slight amount of down, so luckily the balance point came out on the nose, with no extra work or weights needed. Knife edge flight is going to need a bit of mixing to be right on, but after only two flights nothing really to complain about. The oversize Contender seems to almost land itself.

Rudder input does add a little weirdness due to the wing with no dihedral. The first hammerhead was a bit weird, but other attempts were better. The plane was just letting me know that it is not like all the other planes in the hanger, but it is a very good flier with just a few quirks of it's own. Looking forward to getting more stick time on it, and can only say after the first two flights that it is a keeper.

After the Contender test flights, I flew first flights on an old favorite with a new radio in it. It is a scratch built pattern plane built in 2006. I had just replaced my last 72mh radio with a new 2.4 8ch Tactic 850, so it needed to be trimmed out and reset. First impression is it feels just like the old Futaba transmitter but lighter.

Thanks to everyone who chimed in on this build, and hope a few of the newer guys have gotten the bug to give building a try. It sure brings a lot of joy to my hobby hours. I have already started another scratch build over on Groups. This time it is a updated 2 meter Kaos build. Glad to have you drop in.
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Old 02-19-2015, 11:56 AM
  #37  
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Tom, that's a beautiful plane in the air!!!! Well done!
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Old 02-19-2015, 12:31 PM
  #38  
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Good report... enjoy for a long time.
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Old 02-19-2015, 03:31 PM
  #39  
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Originally Posted by tomclark View Post
My apologies to all you folks that live in the great frozen north, but today we had a perfect flying day. 70 degrees and a light breeze right down the runway, so it was finally time for the first flight. All went very well and was much as expected. The ASP was on it's best behavior and ran perfectly. The Contender, to use an old term, "Flies like it is on rails." Round loops and very axial rolls are extremely easy. Inverted flight just takes a slight amount of down, so luckily the balance point came out on the nose, with no extra work or weights needed. Knife edge flight is going to need a bit of mixing to be right on, but after only two flights nothing really to complain about. The oversize Contender seems to almost land itself.

Rudder input does add a little weirdness due to the wing with no dihedral. The first hammerhead was a bit weird, but other attempts were better. The plane was just letting me know that it is not like all the other planes in the hanger, but it is a very good flier with just a few quirks of it's own. Looking forward to getting more stick time on it, and can only say after the first two flights that it is a keeper.

After the Contender test flights, I flew first flights on an old favorite with a new radio in it. It is a scratch built pattern plane built in 2006. I had just replaced my last 72mh radio with a new 2.4 8ch Tactic 850, so it needed to be trimmed out and reset. First impression is it feels just like the old Futaba transmitter but lighter.

Thanks to everyone who chimed in on this build, and hope a few of the newer guys have gotten the bug to give building a try. It sure brings a lot of joy to my hobby hours. I have already started another scratch build over on Groups. This time it is a updated 2 meter Kaos build. Glad to have you drop in.
Congrats on the flights! Beautiful skies there, but I would expect no less in New Mexico. One thing I have noticed about larger scalings of projects is that they always tend to land better.
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Old 02-24-2015, 10:49 AM
  #40  
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Contenders have been known to have adverse roll couple with rudder, which is the result of a low-wing aircraft having zero dihedral. The original airplane was designed the way it was because it was intended to be easy and fast to build. I built a kit from the very first production run and had the airframe built, using carpenters' glue, in under a day, not counting glue-drying time. People learned to add the canted-up wingtips so that the airplane would have the desired proverse roll coupling with rudder application.
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Old 02-11-2019, 06:57 PM
  #41  
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Originally Posted by Bax View Post
Contenders have been known to have adverse roll couple with rudder, which is the result of a low-wing aircraft having zero dihedral. The original airplane was designed the way it was because it was intended to be easy and fast to build. I built a kit from the very first production run and had the airframe built, using carpenters' glue, in under a day, not counting glue-drying time. People learned to add the canted-up wingtips so that the airplane would have the desired proverse roll coupling with rudder application.
Just started finishing a 90% built Contender that was gifted to me... The manual showed two tip versions and why... I chose the upswept tips as it described better landing traits, little to no adverse yaw . Having had that problem way back in the late 70's on a Balsa YSA Smoothie I made T tailed , with one wheel under wing and huge rolled down tips like the smaller ones on the Ace Mach None, . The Smoothie flew really nice, took off and landed fine on the one wheel and nearly touching tips but other than steering for take of or landing you dare not touch the rudder as it would violently roll the plane in the opposite direction.

BTW... it took me about a half day and a ton of balsa dust to shape the LE and TE ...so how your doing all that , using carpenters glue and in under a day is beyond me ...and I'm quite an accomplished builder over the years...really one of the faster ones. I hated the shaping /dust part... but all the rest is fun.

....so upsweep fro mine...and BTW IMO, it looks so far a lot cooler than the more or less blunt looking straight tips.

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Old 02-11-2019, 07:07 PM
  #42  
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Glad to see some life on this thread! As for shaping leading/trailing edges, I use a whisker plane or a Master Airscrew finger plane to get to initial shape before sanding. I like to do it outside though as you do get a lot of shavings!
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Old 02-12-2019, 03:50 AM
  #43  
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When I got back into RC and started building again, I built similar to Tom. Just draw the lines needed and build. Since I found his threads, I’ve adapted some of his techniques for building. I’ve also learned a lot. The Contender is on my list to build, some day.

Regarding shaping LE-TE, as was pointed out, a razor plane does most of the work. Then sand final shape.

Just for information, Tom has not posted for a few years. He had a stroke, still active but unable to type. This was posted on another forum in response to an inquiry about him.

"Sure, he’s well, but he had a stroke that interferes with his ability to type. He has all his abilities except he still has a very hard time typing. It has to do with the region of his brain where the stroke occurred. But he drives, plays golf, flies his planes—he’s part of an RC club out here—and that fabulous intelligence is all there. It was so nice of you to reach out, I’ll tell him. No worries, Tom is doing great. We have 7 households out here and we all socialize together every week. So he’s fine and also very active.



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