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The VVRC 40cc Twin "Classic" comes with all these quality pieces. And, yes, that is a Walbro carb as standard equipment! Click image to enlarge

VVRC 40cc Twin "Classic"

A very popular powerplant just got better

Text, photos and video by Tom Hintz

Posted – 12-7-2018

The original VVRC 40cc Twin has enjoyed a remarkable popularity within the RC community. Where most people would leave well-enough alone, the folks at Valley View RC (Puyallup, WA) recognize the value of improving a product. The result of that forward-thinking is the VVRC 40cc Twin "Classic".

The Basics

The VVRC 40cc Twin "Classic" weighs in at a trim 44 oz, with the included mufflers and Rcexl ignition module. The ignition can be powered by 6V to 12V with the most common battery power being 7,4V LiPo. With a 32mm bore and 26mm stroke the VVRC 40cc Twin "Classic" cranks out 4.7 hp at 7500 rpm. It has an operating range of 1500 to 6800 rpm (static) and swings a 21 X 8 prop at 6800 rpm. The suggested fuel/oil mix is 40:1, with 87 octane gasoline. Rather than use a 35cc prop bolt system they went to a common 55cc bolt (5mm) diameter and a dual bolt pattern for the additional prop security and ease of aligning the prop for hand-flipping.

Though it defies predominant “real-world” logic, it appears there might be a “standard” overall engine/mount length emerging in the RC industry. The VVRC 40cc Twin "Classic" comes with 30mm standoffs that produce a 160mm prop washer to firewall dimension that fits many planes without modification. Life cutting and fitting cowls is getting better!

To better handle its robust power output the VVRC 40cc Twin "Classic" now sports a stronger crankshaft that runs within a CNC crankcase. A CNC crankcase offers bearing alignments that are very true, reducing parasitic drag and heat buildup. Both are critical factors in engine performance and lifespan but not often seen in similarly priced engines.
Another major factor in performance, reliability and value is the genuine Walbro carburetor. Where most engines consider the Walbro an aftermarket improvement, it is standard fare on the VVRC 40cc Twin "Classic". For many RC’rs a factory-installed Walbro, is like getting another $50 off the purchase price.

The VVRC 40cc Twin "Classic" and their Generation 2 are the only twin cylinder engines that fit such a wide range of 30cc airplanes. Plus, the 8” distance between spark plug caps mean these engines fit inside many 30cc airplane cowls with minimal cutting. These engines use the smaller 1/4 X 32 spark plug mounted at an angle to further reduce cowl interference.

New is a CNC-machined crankcase (left) that supports a new, heavy-duty crankshaft. The cylinder heads have angled plugs (right) that help keep this engine within more cowls without excessive cutting. Click images to enlarge

The standard equipment Rcexl ignition included with the VVRC 40cc Twin "Classic" is something else that has been an add-on, additional expense piece with many engines. These Rcexl ignition systems have long been considered one of the best and have frequently replaced factory ignitions. Whatever they are doing on the inside of these ignitions, all good stuff is happening on the outside!

In the Air

Getting the VVRC 40cc Twin "Classic" into the air turns out to be easier than most. The Walbro carb and the design of the engine itself made getting this engine started the first time surprisingly easy. And, from the first time it ran, the carb was adjusted so that the engine idled well, had remarkably sharp throttle response and made no attempt to run hot.

Most new engines have a little difficulty drawing fuel to the carb after they have sat idle for a day or more. The VVRC 40cc Twin "Classic" showed that same tendency until I got paranoid about the sharpness of the throttle response and decided to richen both carb screws by a whole “screwdriver blade width”. Following that tiny carb change it continued to run perfectly in the air but drawing the fuel to the carb the first time each day takes only a few flips with the choke on. After it pops, it starts around two flips later. Who woulda’ thunk it, an RC engine as a labor-saver.

I flew my Hangar 9 RV-4 with a Vess 20B prop bolted to the VVRC 40cc Twin "Classic" and both seem very happy in the air. Mess up an approach and after a long glide at idle I can hammer the gas and away it goes. I like it when an engine helps me cover up a mistake.

The power is abundant and consistent across the rpm range. I never feel like the power is sagging or the engine lagging at some point in the throttle throw. Get the throttle servo set up so movement from idle to full speed is consistent and so is the progression of power production.

After many flights in the Hangar 9 RV-4 I realized that I was not thinking about the VVRC 40cc Twin "Classic" but rather paying attention to everything else about the plane. The VVRC 40cc Twin "Classic" works so well that it fades into the background and becomes part of the throttle stick. The VVRC 40cc Twin "Classic" is not teaching me to anticipate deadsticks or to worry about having enough power for virtually any situation.

Finding a genuine Walbro carb as standard equipment (left) is like getting another $50 off the purchase price! 5mm bolts in a common 55cc pattern (right) keep the prop in place. Click images to enlarge

Conclusions

I have been a fan of the 40cc twin-cylinder engine concept for a long time. Now with the VVRC 40cc Twin "Classic" I might be drifting towards obsession. This is a great running, surprisingly powerful engine. This Review has taken longer than most because I have been flying the Hangar 9 RV-4 to get data for its Review. Throughout that process the VVRC 40cc Twin "Classic" was never a concern. It kept running and performing better than I anticipated. It just runs great and lets me focus on other things that might not be so reliable.

The one aspect of the VVRC 40cc Twin "Classic" that seems a bit out of the ordinary is the $439.00 (11-14-2018) purchase price. I thought originally that maybe the mufflers were extra, but they are standard. It’s the price that is below standard.

If you are planning to build a 30cc-size plane the VVRC 40cc Twin "Classic" should be on your must-see list to power it. This is a hugely popular size plane and the VVRC 40cc Twin "Classic" brings out the best in these planes. Sure, it has lots of power but more importantly is its ease of use and dependability.

Visit the VVRC 40cc Twin "Classic" product page – Click Here

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