After looking for several weeks for a ducted fan jet, I noticed on RCU that http://www.easytigermodels.com/
was running an introductory sale on his F-22 70 mm EDF jet. According to his site, the F-22 was a decent performer and large enough to be able to easily track while flying. It came with the following pre-installed; servos, 70mm fan unit, brushless motor, speed control, and BEC. In addition to all that, the model was supposed to handle well in the wind which is something we have quite a bit of in West Tennessee. After numerous e-mails sent back and forth to Curtis (All of which he patiently answered.) I decided to spend my hard earned cash and order one. The model arrived via USPS within days in a plain brown box.
As you could see from the photos, there really were not many parts to the F-22 so assembly went fairly quickly. As mentioned earlier, all the servos were pre-installed as was the ducted fan, motor, speed control and supplied BEC. The plane was pre-painted with flat paint and all decals applied. I used foam safe CA glue from ZAPP products throughout the build. http://www.zapglue.com
The first things that I attached were the control horns to the rudder and main wing control surfaces. Each horn only had two screws securing it to the foam so I added a little bit of CA to the foam for extra security. The hinge hardware was good quality but I still checked each hinge to ensure it was seated and glued properly.
Once the control horns were attached, I put the landing gear in the wings. Unfortunately one of the brackets was missing so I got with Donnie Lyons who is a local pilot and excellent scratch builder. He helped me solve the problem by making a new one out of very thin ply. Curtis from easytigermodels.com offered to send a replacement part as soon as he read my email. Curtis also assured me he would bring the missing part up with the factory. The front nose gear assembly was also pre-installed and all that it needed was the front wheel put on.
After the landing gear was attached to the F-22 all that was needed was to install the main wing, horizontal tail and vertical tail. Curtis from Easytiger models had mentioned in one of his e-mails that it was a good idea to pinch the ends of the ends of the foam slightly before installing so that they would slide into the fuselage easier. His trick worked great, I attempted to install them without pinching the foam and it was too tight a fit. The nose cone slipped on the front of the fuselage and the F-22 was ready to have its control rods installed and radio set up.
I used my old trusty Polks Tracker II radio and installed a Seeker receiver in the jet. The elevators and ailerons were linked together when I moved the radios stick so I set the plane up as a delta instead of a normal plane. I was curious to see how having them linked affected the flight characteristics. There was plenty of room in the compartment for the receiver and it seemed unnecessary to secure it. The F-22's center of gravity was listed at 660 mm / 25.98 in from the tip of the nose cone and it balanced a little bit nose heavy with the battery installed.
The cockpit was begging for a little detail work so I headed inside to do some research and skipped attaching the canopy until after I painted the cockpit. While the cockpit paint was drying, I hooked up my Power Analyzer Plus from http://www.medusaproducts.com
to check and see what the motor was pulling static. 33 amps and 417 watts was the result at wide open throttle. Humm, I need some batteries capable of higher amperage. 2100-2200 20c packs may be better suited for this application.
It was a beautiful day in West Tennessee and I met Nick King, Donnie Lyons, And Dave Huff at the sod farm where we fly most Sunday afternoons at. If you're ever in West Tennessee on a Sunday afternoon, let one of us know and we can get together for some stick time.
I maidened the plane and found out that I didn't have my radio set up properly. The F-22 took off quickly on hard packed dirt but was very touchy in the air. I had the expo set up improperly. So after trimming the plane out, I brought it in for a landing. As I was setting it up for the landing, I noticed the plane was missing a landing gear so I set it down as gently as possible without a gear. (Dave Huff sent me a photo of the gear falling out, see if you can spot that picture.) The landing didn't go too badly under the circumstances, pulled one of the elevator hinges out which stripped out one of the elevator servos, and got some mud on the underside of the plane. I had a Cirrus 9 gram servo handy and changed out the broken gears then fixed the hinge with some foam safe CA glue. Then fixed the expo on my radio and the F-22 was ready to fly again.
I don't want to talk about my next flight. Let's just say it went badly through poor battery preparation on my part. The F-22 took a very nasty landing without breaking any foam. It showed itself to be a tough bird. The only real damage was another stripped servo. It was time to turn the F-22 over to Nick and let him put the plane through its paces. Nick was kind enough to email his thoughts plus some flight comments about the F-22, following is what he had to say:
The plane overall is a smooth flier. It's not going to win any speed records, but it is faster than the typical parkflier. It's responsive, which could get you into trouble if you're not prepared for it. It seemed like a large plane for it's weight, and I was surprised at it's toughness. It's size makes it easier to see, but the overall gray scheme will keep one on their toes for the entire flight, especially with the rolls the F-22 was capable of. Although I am not fond of RTF setups, this plane performed admirably. If it were mine, it would have a hotter motor, and possibly a larger battery before too long...
The 2200 4s1p batteries that I ordered came in the day after we had done the maiden flights. The following morning I loaded up the F-22 and headed back out to the sod farm. Winds were around 14 mph with up to 22 mph gusts. The Power Analyzer was hooked to the new batteries and showed 37.6 amps with 530 watts, much better than the readings with the 1800's.
This gave me a lot more confidence even though the winds were quite breezy. Take off rolls were much shorter with the new packs. The F-22 handled the wind with no problems and there was plenty of power to fly it when heading into the wind. The plane rolls well as Nick stated earlier and loops are a hoot to do with the elevator tied into the ailerons. I tried hard to stall the plane but with the large wing area it just mushed along until I applied power, there wasn't even a need to drop the nose to pick up some speed. The feeling of the center of gravity being slightly aft was gone. It flew well inverted and I was very happy with the performance. Landings needed a long base because the plane wanted to just float in and if I applied power trying to land I would overshoot where it needed to hit the ground at. Nick was right, I needed larger packs.
I flew four times before it was time to go home for lunch and really hated to leave the field even when it was after time to head to the house. The F-22 has earned a place in the trailer I haul my planes in when driving my Valkyrie to the field!
A huge: "Thank you very much." to Nick King for photos and flying the F-22 while I videoed the flight, Donny Lyons for taking photos and Dave Huff for taking even more photos. I really liked how the plane flew, it was super responsive to control input and was easy to track because of the planes size. It moved along at a fast pace when given full throttle and slowed down nicely. My heart was still beating fast after turning the sticks over to Nick for our third flight of the afternoon!
Video for Broadband:
Video for dialup:
*Fairly sturdy plane, actually surprising for this kind of foam.
*Super quick build, instructions easy to follow.
*Nice performance on 4s1p 2200 cells.
*Good appearance overall.
*Large size plane for poor old eyes.
*Ability to handle wind, it flew quite well in brisk winds.
*Glue used by the factory on the control surface hinges. (Triple check these, then check before every flight.)
*Decals not as durable as they should be.
*Accessibility of servo gears when stripped out. (You have to pull the servo partially out of the foam.)