As I've mentioned in at least one other fixed wing write-up, it is winter time here on the homestead. Winter gives me time to work on a project or two and catch up on other R/C related things that I put off during the flying season.
This write-up is about the Twisted Hobbys F-22 Rator EPP foam airplane. The Raptor sports a 29" wingspan supported by a 39" long fuselage. For this build, I used Bob Smith Industries Foam-Cure to glue the EPP foam together. I've also used Beacon's Foam-Tac for EPP projects. Both do a good job and I'll use which ever one I happen to have on hand.
The Raptor is a straight forward EPP foam build. Some of the Twisted Hobbys (TH) planes are more involved, in my opinion. I would list this one as the easiest one I've done. As with the other TH planes, there is an RCGroups build thread that is always a welcomed addition to the factory build instructions. Shortly after the plane was introduced, one of the forum contributors modified his Raptor for movable twin rudders. There are no instructions for it but once you look at a few photos, a person should be able to integrate the changes into their build. This is what I did and it worked just fine.
While we all know that the F-22 Raptor is a jet, this particular model is powered using a regular motor and propeller rather than a ducted fan. As such, it is a pusher prop configuration and is called by some a "prop in a slot". This setup results in more propeller noise than a conventional plane. If you fly in a neighborhood park, which is a perfect setting for this plane to be used, you might want to consider a different location or a different model.
This web article is not intended to replace the build instructions that one would download from the Twisted Hobbys website. While I built the F-22 Raptor, I snapped a few photos to include here along with my own comments about them. I hope you find it helpful. Spending some time browsing the previously mentioned RCGroups thread is highly recommended too.
I'll borrow this paragraph from one of my other EPP build articles. I use a piece of Dow blue insulating foam, used in house construction, as a flat surface for pinning the foam pieces in place while the glue dries. The above pic shows the left and right wing halves as such. I also tape a piece of freezer paper (for wrapping meat) over the blue foam. This keeps any excess glue from bonding my EPP foam to the work surface. I've always had good luck with this Dow foam being straight/flat. You need a flat work surface when building so you don't end up with twisted or crooked wings, tail feathers, etc. Before I start a project, I check my foam board with a long metal straight edge to ensure it is still smooth and flat.
Here is a good example of what I was just explaining. I have just glued the wooden spar into the wing assembly of the Raptor. To keep even pressure on the foam so that it adheres to the spar and remains straight, I have pinned the foam onto my construction board. If you were using CA, you might be using a different technique and I'll leave it up to you to determine what that would be. As I mentioned, this is all happening during the winter season and I've got plenty of time for the glue to dry. Besides, that's part of the reason I have Netflix!
One of the things I like about the TH kits is their attention to detail. In this photo, a small alignment tab has been cut into the foam. In this particular case, I'm joining the elevator to the fuselage. This little tab prevents you from accidentally installing the elevator upside down since there is but one tab cut into this piece. If you tried to install it the incorrect way, it wouldn't align properly, so it prevents you from trying to figure out how to "undo your oops" after the glue dried.
Here is the last piece of the main fuselage being glued into place. Once the glue dried, I cut the little tabs holding the laser cut pieces in place in the fuselage. The rest of the fuselage fits very securely into these cutouts. Twisted's attention to detail on this is equally as good as these laser cutouts are so much better than what I could have done by hand.
With more of the fuselage glued in place, the servo were positioned in their pre-cut slots. I had some 9 gram metal gear servos in my parts bin that I used for the elevons. The fit for the pre-cut slots was spot on.
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