|Wingspan:||22" / 558mm|
|Wing Area:||254 sq. in. / 16.4 dm. sq.|
|Weight w/o LiPo:||9.8 oz. / 277.8g|
|AUW:||16.8 oz. / 476g|
|Length:||30.5" / 774.7mm|
|Wing Loading:||7.2 oz/cu.ft. Wing Cube Loading (see note below)|
|Battery:||1600 3S 11.1 volt 20C|
By now, you all know I really like EPP stuff. It is beyond durable, and even though it is not the smoothest looking aerodynamic surface, it flies incredibly well through a very wide range of flight envelopes.
The F-22 is my third BudgetRC plane. My first, the P-51, was great fun. Then I built the ULD. Each of these share a few common building techniques, including the painting, use of carbon stiffeners and lightweight electronics. The F-22 diverges somewhat with a different hinging technique, but overall, the use of EPP foam, carbon and laser cut parts is consistent.
Just like all the other great airplanes from BudgetRC, the F-22 arrived in a small box, bagged for assembly. The instructions can be downloaded so youíre sure to get the most current version.
I tell you, the good folks at Budget are generous and send you plenty of materials with which to build. With the Ballistic power pack, they also give you everything you need.
Get ready to build by making sure you have some heavy, flat and straight weights to hold the components down during the build. It is critical you have a flat building surface and have some of the following at the ready.
The wing is the majority of the airframe build. It is comprised of two main pieces of laser cut EPP. You will love the detail and crispness of the cuts. Nothing is cut without a purpose.
Make sure you do everything in your power to pull the two halves together tightly as you glue. Once I had the two sides in place, I installed the fat carbon stiffeners.
The canopy consists of two halves. I installed the carbon first and then glued the two pieces together making sure to keep it straight and flat.
The elevons require the use of hot glue as hinges, and they work really well. The key is to not use too much and to use a straight edge to smooth the glue for a thin layer.
There are a few steps that need to happen before building up the fuselage and while the wing is flat to help keep things square and true. Install the tail fins next with hot glue
The fuselage box is easy to construct, but just like everything else, needs to be square. The sidewalls extend all the way back to the elevon hinge and support the servos. Holes are cut in the wing to receive the sidewalls perfectly.
There is one small piece or carbon to install under the wing and through the fuselage lower portion that steadies the wing and stops any flutter at high speeds.
I started with a couple coats of silver spray paint. My wife did the detail work and used colors and shapes like we had seen in the northwest.
The motor mount is ply and must go on correctly. It slips into place, and I CAíd it, but also hot glued the mount thoroughly. You should have the motor on the mount before you glue it into place.
Servos install on both sides and are secured with hot glue. I had to install the control linkage guides down each sidewall and secure them with hot glue. I trial fit these first.
From there it was a matter of getting the receiver, ESC and battery in place for the best CG without adding any weight. Because I used the AR6200, I installed the main receiver within the fuselage box and the auxiliary up and along the canopy.
The CG is located very close to the point where the wings begin to extend outward. The battery has to be placed along the canopy wall and as far back in the fuselage cavity as possible without hitting the prop (see above picture). The battery seems heavy (156 grams) but the F-22 is well engineered to have the correct CG with the battery all the way back. I did fly the F-22 with some larger batteries with no problem.
As a final note, make sure you put the prop on correctly. The pusher requires the prop to rotate so the leading edge of the prop is correct. Trust me, it is easy to get it wrong, and your airspeed will suffer.
The F-22 is a screamer. At full throttle, thereís enough noise to get just about everyoneís attention. A word of caution is provided by BudgetRC with regards to full throttle operation with the Ballistic Power package: Use short ten second bursts. I did this at first, but soon firewalled the throttle and have been running the F-22 full bore around and around with no problems. You will get only about 2.5 minutes at full throttle.
1600 (battery capacity)/36000(amp draw)= .045 x 60 Ė 2.7 minutes of run time. The prop turns at 17,500 RPMs at 36 amps and about 350 watts.
I did get battery temps in the 120 degree range, and the motor heats up pretty good too, but the good quality components provided by BudgetRC stood up to this kind of abuse.
I think while a few loops and rolls are in order, this F-22 is all about speed. I would climb upwind and turn downwind as steeply as possible for maximum speed. The climb is pretty good, and at about 45 degrees (as you can see in the video), it climbs completely out of sight. It is a blast to get the F-22 as high as you can and then start to build speed as the plane passes by. I would guess terminal velocity is around 70-75 MPH and is limited mostly by drag. I consistently got speeds right at 70 MPH.
The F-22 is a hand launch plane, so watch your fingers! The best method for launching is to hold the F-22 between the tail elevons and just give it a slight underhand release upward. You can tell at full throttle that the F-22 wants to leave your hand, and no real effort is required.
The landings are incredibly stable. Nothing I saw was even close to a stall, and the glide was very stable all the way to the ground. The F-22 is a bellylander. Note that I land pretty hot, but totally under control. Honestly, I never stalled the F-22. It can handle a large flight envelope.
Some rolls and loops and inverted flight are certainly in order, but, full out high speed passes are the preferred flight characteristic. Climbs are powerful, but not quite vertical. I experimented with several batteries in the 150 gram weight class, and in the end I measured 69 MPH as my max speed. Not bad. I used Eagletree's Micro Airspeed sensor for reconciling the speed. These little units are awesome and easily mount to the airframe of the F-22.
I think just about anyone can fly the F-22, but it is really not intended for beginners. Some flight time and the desire to find more speed is what this plane is all about.
Itís another well-designed and produced product from Budget RC. I liked the building method, the price, the EPP and the flight characteristics. They have gradually created a hangar of fine aircraft. Keep your eyes open for more.
What I liked:
What I didnít like so muc:
For some, WCL is a measure that more realistically indicates the flying ability of an aircraft. Here are some links for you to read through and a WCL calculator for your use.Last edited by Angela H; Oct 29, 2009 at 06:52 PM..
Something is a miss...
I did some doppler readings on some of your level passes and I was only seeing between 50 and 60 mph. I know you got an eagle tree reading of 69 mph from a 45 degree dive.
At 36 amps of draw on a 3500 kv motor, you should be going a lot faster with a 22" 16 oz plane.
My Stryker (37" wing span, 23 oz) is using a 3500 kv inrunner with an APC E 4.5x4.1 prop. It draws 27 amps static but I've dopplered it at 83 mph. I'm drawing 9 amps less than you and going more than 20 mph faster on a 7 oz heavier and larger wing span plane... Your plane is smaller and should have a lot less drag than mine so yours really should be going a lot faster...
I'm thinking something must not be right with the prop you chose... I hear lots of screaming but not a lot of speed (almost sounds like it's churning or cavitating a little).
What prop are you running? Maybe a better prop choice will give you much better performance and better duration too...
Here's a little video of my Stryker for reference: https://www.rcgroups.com/forums/show....php?t=1036796 (similar sounding RPM's from both our planes but mine is noticeably faster....)
I'm not dis'ing the plane. I think it's neat but just wanted to point out that something didn't seem right with the speed and amp draw...
Last edited by cjbucher; Nov 10, 2009 at 05:36 PM. Reason: added video link
Not sure you assumed things correctly. I videoed the F-22 when I had the prop on backwards. Later flights were used to measure the speed after I flipped the prop. Your measures are close as I was getting about 58 MPH with the prop in backwards. Sorry for not saying the prop size. I will check and post asap. Also I understand noise form the prop increases the closer it is to the airframe.
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