The H-29 Pushprop Jet by chara is a small park jet with a mid-mounted motor and taileron configuration. It uses only two servos and three channels. The thrust pushes directly through the tail, being slightly diverted by the elevons; giving this model superb performance similar to other, more complex, thrust-vectoring models. Last time I wrote about this plane I had flown it with a 7×5 APC prop and didn’t like the performance.
So I finally tested two other propellers with the 28-26 1360kv motor. Previously I had chosen a seven-inch propeller because I thought if I went up to the recommended eight-inch it would strike the wood dowels on the twin booms but later noticed there was plenty of clearance, so I got a GWS 8×6 and an APC 8×8 today and went out to test which would give me better performance. On the bench test, the GWS 8×6 seemed to give me much more thrust but I found out otherwise at the field.
APC propellers are built for speed. Once they reach enough RPMs, they produce efficient thrust. GWS propellers, in the other hand, are built for general-purpose and scale flight. They produce max thrust almost immediately but are slightly less efficient at higher RPMs.
Watch the video and enjoy.
Wondering how I shot the video and flew at the same time? Here’s the rig:
I hate Z-bending pushrods! It’s hard to get it right unless you have one of those expensive Z-bend pliers and it’s an impractical way to connect servo arms to control horns.
You know what I LOVE? I friggin’ love Dubro Kwik Grip EZ Connectors! You’ve never heard of ‘em?! They’re connectors that allow you to use your pushrods without bending them at all. You install the EZ Connector on the servo arm, slide the pushrod through it and tighten a little screw with a hex (Allen) wrench.
No more screwing the clevis in or out! If you want to adjust the length of the rod, just loosen the screw on the EZ Connector, hold the rod at the precise position you need it and tighten the screw again. Voila! 5-second fix.
Control horns are the plastic pieces where the pushrods push and pull on the control surfaces. I like small, light horns that snap-on. I also glue them on for safety.
My favorite horn so far are the Light Weight Horns sold at HobbyKing. They are very small, about 17mm high from the base, snap-on with two pins and hold on tight. They have three position holes for the clevis.
Since I found them I have used these in all my foamies, including the Park Jet and Super Cub (ailerons). I would only recommend these for small and medium-sized models. For larger models, a bigger, stronger horn might be better suited.
I built Chara’s H29 Jet last week. I wanted a fast-to-build, simple, fun jet to fly at the park. I used Elmer’s Foam Board, wood dowels, and Gorilla glue. I knew it would end up heavy, but I wanted the added weight for stability in the wind. I went with an Exceed RC Alpha 370 brushless motor, 1360 kv with a 7×5 prop.
It few well but nowhere as fast as I want. I had the rates set at 100% for high and 50% low but that was way too much. I have to try 50% high and 35% low next time. I read up on people using 8×7 props with this motor so I’ll go with one of those next flight.
I just ran across a great series of articles written by Eric of HoverAndSmile.com where he explains in detail a lot about transmitters and how they work. He has made it very easy to understand for those who have never flown RC before or have little experience doing so. I’d like to share these articles with my readers since I know many of you are new to the hobby. Here are articles One, Two and Three.
Flew my Super Cub at Ives Estates Park in Aventura last Sunday. the winds were at least 25 knots and it was so much fun. My son was having a blast with the plane hovering so close. I did some fun STOL flying like the real Bush Cubs ^_^
A few weeks ago I started to build a full-fuse foamie from Elmers’ foam board, Gorilla Glue and Plywood. It came along nicely and was looking good. I named it the T-32 Thunder. Unfortunately, on its maiden flight I crashed it because of strong winds. I believe it needed other changes for it to fly properly, anyways.
The wing survived the crash and I might rebuild the airplane someday. I still have a lot to learn.