Great Planes

Reactor Biplane .61


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Stock Number: GPMA1023
Wingspan: 48 in (1220 mm)
Wing Area: 1145 in² (73.9 dm²)
Weight: 7-7.5 lb (3170-3400 g)
Wing Loading: 14-15 oz/ft² (43-46 g/dm²)
Length: 58.5 in (1485 mm)
Requirements: 4-5 channel radio w/7-8 servos; 2-stroke .61 cu in (10 cc) or 4-stroke .70-.91 cu in (11.5-15.0 cc) engine; OR RimFire™ .80 (50-55-500 kV) out-runner brushless motor, 60A brushless ESC & (2) 11.1V 3200mAh (3S) 20C LiPo battery

My NEW Reactor is getting re-defined to... GASOLINE POWER!

I have a new Zenoah G20 that's just laying around so it's time to connect up the Reactor and the Zenoah for a "one-of-a-lind"  little GASSER.  This engine install will be a little tougher than one's I've done in the past. The fit is really tight, but it will go. It will install similar to the Super Skybolt. However, the Reactor already has provisions for tail mounting the servos. That's a big time-saver.

The first item on the list is to make provisions to strengthen the firewall for the gasoline engine. The original "T" nuts need to be removed and re-set for the Zenoah radial mount. Technically, the Zenoah G20 should need a 7/8" standoff for this particular aircraft. However, I am going to mount the engine directly to the firewall. The reason for this is to compensate for the added weight of the G20. The Zenoah engine weighs 11 ounces more than a OS .91 FS engine the aircraft calls for.

I will detail the fit & finish as I progress. 

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Here you see the engine mounted. Notice that I mounted straight up to the firewall. The reason for this is to keep the G20 moved as far back as it will go. This will help offset the extra weight of the gasser.

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This shows the nice hatch opening the Reactor includes. This is here for the electric powered option, I will use it for my ignition module. The landing gear is fiberglass, although it's nice it could stand to be a bit stiffer for the gas engine.

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As you can see, the Reactor has massive ailerons on both top & bottom. And check out the tail feathers! These are HUGE!

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  I used full size Hitec HS625MG servos, so the servo mounting cutouts had to be enlarged. Thusfar, Great Planes has done a good job on this aircraft.Great Planes provided a servo template for this job! They also provided a nice CG stand!

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AGAIN, I must stress that the the stand-off call-out from the firewall to the prop hub is 5 3/4". My G20 has a length of 4 7/8". I won't move the engine out to the specified distance as this will help with extra weight of the engine. The CG is perfect without any weight added to the tail. As you can see, this engine install is super-clean! I opted not to use the engine cowling... as there's not much cowling left after cutting out for the carb & muffler. However, the cowling will go on if you must have it.

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This is the access hatch setup for my ignition module & gas tank vent. It worked out quite well. I use clear packing tape to secure the hatch better. All the fuselage control surface servos are installed and functioning. The gas tank is installed and connected, and the ignition is 85% done. I need to install an on/off switch for the ignition. You can see I fiber glassed all the way around the firewall. You can cover the glassing or simply paint it. I opted to paint my glass.

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Here is where I put my SpeKtrum receivers. Not only is this a clean install, it also lets you monitor your receivers. SpeKtrum Radios equipped with LED's (in the receivers) that report any errors.

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The Reactor came in at 9 pounds, 2 ounces with a full tank of gas. Because I mounted the engine directly to the firewall, the CG was dead-on without any adjusting. I added some cables & springs to the landing gear similar to a J-3 Cub, to stiffen the gear. This worked great! 

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Here is what the Reactor Bipe looks like without the cowling. I have no problem with it, and it sure keeps the engine cool.

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The maiden flight was excellent! The reactor didn't need any trim at all, and it tracked perfectly at any speed and any orientation. This aircraft flies on rails and does precisely what you tell it to do. I may play with the CG to find the perfect balance.  However, neutral CG works well for me at this time.

Regardless what engine you may use, the Reactor flies exceptionally well. I would recommend a lot of exponential if you use maximum throws. My exponential is set at 75% and it's easy to fly & control. My Zenoah G20 was an excellent engine choice for this bipe. My Reactor will take-off vertically from a dead stand-still in about 3 feet, even on a grass runway!  It will also Harrier Land with the best of them. If you are into 3D, you won't be disappointed with this bipe. It performs virtually all 3D maneuvers and its super stable at any speed, even when hovering. The roll-rate is absolutely mind blowing! So if you do "rolling-turns" you will be very busy!  Because I fly off a grass runway, I reversed the landing-gear to help manage the ground handling.  IE: stop nose-overs.

The prop of choice appears to be an APC 17x6 Wide Blade. It provides excellent thrust at 8600 RPM and I will never need full-throttle! I am also experimenting with other props that include 16x6, 16x7, 16x8, 17x4, 17x6, plus several carbon Fiber props. 

This is a really well-made airplane and I have to complement Great Planes for their excellent Quality Control. The fit & finish was top-of-the-line. 


Copyright © 2009 M. B. Fuess-Greater Southwest Aero Modelers