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Apr 13, 2013, 04:39 PM
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Build Log

CARF-Models 2013 Series 3.1m Extra 330SC

Hello everyone. My new CARF-Models 2013 Series 122” Extra 330SC in the Yellow Chequer scheme has arrived.

I wanted to share the research I did before I decided to go with the CARF-Models 122” Extra 330SC. Last fall I knew I was ready for a new airplane for IMAC competition. I had been flying a 118” Extra 300 and having a blast. I had no idea what I wanted to get.

For my new airplane I wanted to find out what the top competitors are looking for in a competition airframe. I contacted the U.S. pilots in the top seven at the 2012 Clover Creek Invitational and the 2012 Tucson Shootout. The U.S. pilots in the top seven at those two events included eight pilots.

I contacted those eight pilots and asked them five quick questions about airframes for IMAC style competition.

- What would you consider the optimal wingspan and weight for sequence work?
- What is the wingspan and weight of the airframe you flew at the CCI/TAS?
- What do you consider the advantages and disadvantages of a wood airframe?
- What do you consider the advantages and disadvantages of a composite airframe?
- What do you look for in a competition airframe?

Seven of the eight responded and they were all very insightful, helpful, and encouraging about the research. They were impressed that I was taking the time to really research what I thought would be the best airframe for me. I also got responses from one of the builders/callers for one of the pilots. That was another interesting perspective.

After talking with these seven pilots, it boiled down to a few common themes.

- The sweet spot for wingspan was 121” to 124”
- The sweet spot for weight for five of the seven pilots was between 41 and 42.5 pounds

Two of them were outside that norm and preferred 39 pounds. One of the pilots wants 41.5 pounds for calm conditions and prefers his 43 pound backup plane in windy conditions.

Based on all that, I still think I’ve hit a good average with the 121” to 124” wingspan with a weight between 41 and 42.5 pounds.
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Apr 13, 2013, 04:40 PM
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The discussion on the advantages and disadvantages of wood and composite airframes turned into discussing custom built kits and composite airframes. At no point in the discussions was a wood ARF considered a top competition airframe.

The advantages of a custom built kit were:

- Easy to make any modifications you want while the kit is being built
- Stiffness of the airframe and wings can be integrated throughout the entire structure if planned and executed correctly
- Options for lightening during construction
- Easier to repair

The disadvantages of a wood kit were:

- Competition wood airplanes have to be built
- Susceptible to hangar rash
- Absorb fuel and smoke into them
- Airframe quality depends on the wood in the kit
- Not as forgiving to weather (climate change humid to dry and vice versa)
- Covering can bubble and wrinkle
- More maintenance (have to keep a close eye on stringers and formers that pop loose)
- Changes with age
- Deteriorates over time
- Not easily replaceable parts

The advantages of a composite airframe were:

- They have a great finish and are quick to assemble
- The composite planes always look brand new!
- Fit together better in the long run
- Easier to build
- Stronger
- Ailerons are stiffer
- Don’t have to deal with covering
- Handle climate and weather better
- Exact same plane every time
- Easy to duplicate setup on backup plane
- Easy to get replacement parts
- Interchangeable parts
- Easier to fit canisters inside (lots of room inside)
- Basically maintenance free

The disadvantages of a composite airframe were:

- Cannot modify anything on them
- Usually the wings are heavier
- Trailing edges aren’t thick enough
- Any damage takes a different skill set to repair
Apr 13, 2013, 04:41 PM
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At that point the composite airframe seemed to have a long list of advantages with very few drawbacks.

The significant benefits I saw for the wood kit were the ability to make changes to the design during the build and the ability to lighten the airframe during the build. Since I wouldn’t change anyone’s design, the weight was the only remaining significant benefit for me with a custom built wood kit. The wood airframe had a long list of disadvantages. The cost to have a competition kit custom built and the wait for it to be completed were also concerns.

With the sweet spot for the weight ranging from 41 to 42.5 pounds and the sweet spot for the wingspan ranging from 121” to 124” wingspan, I wondered if a composite airframe could hit that sweet spot and have the things the top U.S. pilots were looking for in an airframe.

The last question I asked them was, “What are you looking for in a competition airframe?” Two common themes were:

- Long tail moment
- Sharp leading edges for good snap rolls

There were some contradictory thoughts. More than one pilot mentioned wanting light wings for snap rolls. The winner of the Shootout thought the weight of the wings had nothing to do with snaps, but that it was having large ailerons that let you control the stop of the snap. In fact, he said his wings were 4.5 pounds. You have to be able to snap really well to win the Shootout.

The Shootout winner also mentioned his preference for a single place canopy. He specifically said, “like an Extra 330SC, not like the Extra 260”. He actually replaced the canopy on his plane with a single place canopy. The Clover Creek Invitational winner was flying an Extra 330SC.

One of the pilots that has flown the 124” competition wood airframe and the 122” composite Extra 330SC said they both track the same due to the long skinny fuselage, but he thought the Extra 330SC presented better due to flying at a more scale speed.
Apr 13, 2013, 04:42 PM
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Hmmm….. The 122” wingspan composite Extra 330SC seems to be a world class competition airframe. There are two manufacturers that offer an Extra 330SC with a 122” wingspan.

Krill wants $4,095 for the airframe that accepts a 4-cylinder engine. That’s almost as much as a custom built wood kit!! I know it should fly great, but I also had concerns with the longevity of the airframe based on the comments I see online.

CARF-Models offers a 122” Extra 330SC for $800 to $1,200 less than Krill (depending on the scheme). They are known for their durability and strong construction. The Extra 260 I flew in 2006 went through 5 owners before I lost track of it. It still looked brand new. A guy at my field has a CARF-Models plane with over 1500 flights on it. It still looks brand new and is still as strong and straight as the day he put the maiden flight on it. One of the Advanced class pilots here in the Southwest is flying a CARF-Models plane he’s been competing with for the last 5 or 6 years. It still looks incredible and he’s winning contests in 2013!!
Apr 13, 2013, 04:43 PM
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I loved the way my CARF-Models Extra 260 flew. It took me to the top of the podium for the Advanced class at the 2006 Tucson Shootout. I was curious about the feedback on the flight performance of the CARF-Models 122” Extra 330SC.

Spencer Nordquist’s Dad/assistant
Thought I'd update on the SC. After only 24 flights since maiden, my son competed in the Donnie Leseberg Memorial IMAC in Tucson last weekend with the SC. It flew fantastic and he pulled off 1st place in Advanced. This has been the best flying "out-of-the-box" plane we have ever owned.
Spencer flew the Prado IMAC and Freestyle in Chino Ca this weekend and took 1st in Advanced with his 330SC. Plane flew like it was on rails and had plenty of power with the DA170/RE3's. This is fast becoming his all time favorite IMAC plane. It flies fast, precise and presents well. Great IMAC plane.

From Andrew Bird (no relation)
I've got one and like it so much I ordered a second in a custom scheme!

I'm running a DA170 on cans and have loads of power for Advanced sequences. The plane has way better control authority than my old 260 so I can run a forward CG which works great for IMAC and flick in to full rate for great 3d performance. I've got just over 70 flights on the plane now and it's been rock solid.
It seems to have some of the negatives from the Super Extra removed as well - the wing is a little higher, you have more aileron authority and the rudder works better. I've flown quite a lot of different composite planes recently (mainly Krill and Comp arf) and this is the one I'm sticking with. Build quality is good, the plane is bullet proof and flies great.
Honestly - I love my plane. It's working great in the sequences for me and has the control surface power to be put in to high rate and 3d very well indeed. It's tough as old boots - I ham fistedly kept trying to perfect full power, vertical rolling 8's earlier in the week and still not the slightest complaint or bit of maintenance needed. I'd go as far as saying this is the best plane I've ever flown, and I've had my hands on a fair few over the last few years. It will fly straighter and knife edge way better than your old MX2.
I'm running a 30x13EVOL on Zimmerman Cannisters with a DA170. Performance is very good.
I used to have a compy 260 and really loved it. I got into the 330 and am really happy. Control authority is better, it couples less, 3d's way better in my IMAC set up just by going out to high rate.......
The 330 is longer and seems to track better as well. I've not tried one on a 200 yet but the other plane with a DA170 on cans has no problems with advanced sequences and no problems through the unlimited with my incompetent hack handedness not managing power as well as I could do.
The plane is making me look like I fly way better than I can! I don't think I've flown anything that flies as straight as this plane before.
I've been flying an EF 104" Extra recently then took my 330SC out for the day to see how I got on. It's funny having not flown it for a little while, it reminded me how brilliant it is. It's an incredible sequence plane and whilst not as agile and extreme for freestyle as the 104" EF, it's still great for a 40%'er. The huge ailerons help a lot and it just gives you so much time.

From Troy’s “assistant”
It is hands down the best flying plane I have owned. Awesome machine
I let Chris Brislin fly it at a competition last weekend, he was couldn't say enough about it. Loved it
At our Australian champs last weekend, I gave a fly to a couple of the unlimited guys and they had no dramas getting thru the unlimited sequences. Mine has a 150 on re-3's

From Aaron Garle
I saw one perform this weekend with a DA-150 on RE3's. It flew awesome and looks great.
Apr 13, 2013, 04:48 PM
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So the winner of the Clover Creek Invitational flew a 122” Extra 330SC, the winner of the 2012 Tucson Shootout changed his plane to a single place canopy “like the 330SC” because he thinks an Extra with a single place canopy flies better, one of the pilots I interviewed thinks the 122” Extra 330SC tracks as well as the 124” competition wood kit but has better presentation because it flies at a more scale speed, and the pilots flying the CARF-Models 122” Extra 330SC love it!!

Wow!! I think I found my next plane. I contacted CARF-Models to get one in a Yellow Kiwi scheme. Andreas suggested developing a new scheme. I liked the idea. The Yellow Kiwi colors were my favorite, but the scheme didn’t have the great contrast between the top and bottom that is needed on a competition airframe. We went back and forth for two weeks exchanging ideas.

The resulting “Chequer Scheme” was a combination of two full scale schemes with the checkers added to the top. I think it turned out amazing!!

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Apr 13, 2013, 04:48 PM
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I’ll be building this “2013 Series” Extra 330SC for IMAC competition. To stay in that competition sweet spot I’ll be shooting for no less than 41 pounds and no more than 42 pounds.

I’ve selected this equipment:

Smart-Fly Dual Ignition Cutoff
KS-95 rear dump canisters
Mejzlik 30x13 EVO L propeller
Azure Hobbies 6” Carbon spinner
WrongWay RC A123 batteries (2500 mAh for receiver, not sure on ignition yet)
Smart-Fly PowerExpander Competition 12
Futaba R6014HS receiver
Futaba BLS152 Servos (4 aileron, 2 elevator, 2 rudder)
Futaba S9452 Servo (throttle)
Apr 13, 2013, 04:49 PM
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Before I get started, I wanted to get your thoughts on a few items.

- I have some titanium 3/16” axles available. Any concerns with using titanium axles? I’ve used them on a 123” Aero-Works Extra 260 before.

- I’ve got ¼-20 x 2.25” titanium bolts I can use to mount the engine. Any concerns using titanium engine mount bolts? I’ve used them on a DA 170 mount before.

- I can support the canisters using plywood supports with silicone tubing in the corners or with KS comfort mounts (I think that’s what they call them). I’m guessing the plywood is lighter. Any benefits to the KS mounts over the old school plywood mounts?

- I’d like the simplest, lightest fuel tank setup. I have a Dubro 60 ounce tank that I’m told only weighs 5.1 ounces and should drop right in the plane’s tank tray. I saw a 64 ounce Juicy Juice bottle tank setup that is probably lighter and might fit in the tray. I have two of the WrongWay RC 32 ounce Fiji water bottle tanks. I’m planning on running a single line out of the tank setup to the carbs and then putting a “T” in the line before it gets to the carbs. Any feedback you’ve got on these fuel tank options would be helpful.

Thanks for any suggestions or recommendations!!
Apr 14, 2013, 09:57 AM
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Originally Posted by Dean Bird
Wow!! I think I found my next plane.

The resulting “Chequer Scheme” was a combination of two full scale schemes with the checkers added to the top. I think it turned out amazing!!
CARF-Models has two Extra 330SC specials running right now. One is a limited time free color swap on the Chequer Scheme for either the 102" or 122" Extra 330SC. The other is a 10% discount on current U.S. inventory of certain schemes of the 122" Extra 330SC.

Click here for details on how to request either of these specials.
Last edited by Dean Bird; Apr 14, 2013 at 10:04 AM.
Apr 14, 2013, 09:59 AM
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The build starts today. I'll be working while I'm watching The Masters.
Apr 17, 2013, 09:37 PM
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The truck arrived with two boxes. The wings were in one box and everything else was in the second box. I opened the boxes and inspected the contents while the truck driver waited for me to sign the Bill of Lading.

Both boxes were lined with 1" styrofoam. The wings were in padded bags and were in perfect condition. The fuselage was in the other box and was supported by 1" styrofoam formers. The stabs and rudder were in padded bags and all the rest of the contents were individually bubble wrapped and taped into the box to keep them secure.

Everything arrived in perfect condition!!
Apr 17, 2013, 09:38 PM
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The contents included a paper copy of the instruction manual, the "Milled Wood parts bag", and the "Hardware bag". The wood parts bag includes the tank tray and I'm not sure what else yet.

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The "Hardware bag" is marked "General" and includes individual hardware bags for the Rudder, Wings, and Stabs.

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Apr 17, 2013, 09:40 PM
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Since I was starting the build while I was watching a golf tournament, I decided to do the elevator servos first. The surfaces are kept in place with this very low tack masking tape that comes off really easy with no residue.

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I'm installing the Nylon Snap-In Thrust Bearings from McMaster-Carr. Each elevator uses 5 of stock number 7817K53. They have an inside diameter of 4mm and an outside diameter of 5.2mm. I also ordered 4mm carbon tube from McMaster-Carr to use for the hinge pins.

The three brass hinge pins for the rudder and elevators are about 68" long in total and weigh 2.3 ounces.

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I put two 48" carbon tubes and 15 of the bearings on the scale. I have 96" of carbon tube on the scale. The total weight of the bearings and hinge pins will be .7 ounces. I'll save over 1.5 ounces in the tail, the hinges will be smooth, and slop free for a very long time.

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Apr 17, 2013, 09:41 PM
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Each of the phenolic arms in the stab needs to have the hole for the bearings enlarged to 5.2mm. A 13/64" drill bit is very close.

I drilled from both ends with a 12" long 3/16" drill bit. That isn't enough, but it's closer to the 13/64" (plus a little) that is required.

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Apr 17, 2013, 09:43 PM
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Now I used the 3/16" bit at an angle and moved it around the radius while turning the drill bit to remove a little more material.

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Then I used the small 13/64" bit and turned it by hand about 6 times from each side to square off the edges of the hole.

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Then I used a round KS needle file to take out the little bit left in the center.

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Take your time until the 13/64" drill bit turns with just a little resistance in the hole. Then hit it with the round file just a little to get that micro little bit past 13/64" to get to 5.2mm.

I sure wish there was a 12" long 5.2mm drill bit.

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