dkshema
rrProfessor
Location: Cedar Rapids, IA
| OK -- the conversion is getting close to being complete. I'm waiting for a few parts to show up so I can finish the job. Here's a few pictures of the newly converted machine:
 
A few construction comments go here:
First, with the new collective pitch slider, not all micro servos will fit in the frame and allow the heli to fly. I re-used my Hitec HS-56 servos only to find that the HS-56 is too tall from the top of the servo case to the top surface of the mounting tabs. The servo sticks into the side frames too far and runs smack-dab into the new collective lever. Bummer. Other, shorter servos should work just fine. I fixed my problem by making up a couple of shims for the side frame to move the servo outward:
The interference can be seen here:
Two 1.3 mm thick shims can be seen here:
The clearance can now be seen here:
The mounted HS-56 servo can be seen here:
OK. Next problem. The new head has all balls and plastic links, and should be smooth as a baby's bottom in operation. Well, not until you do a minor modification. The shank of the plastic links is just too big in diameter to provide adequate clearance between the ball link on the end of the washout lever and the washout base. As you move the collective up and down, the shanks of the links bind rather severely on the washout base, making that shiny new collective mechanism work like crap. The solution came out of my (ugh!) Align T-Rex parts. I made up two new pushrods for the head using four of the Align plastic links (very skinny, not fat like the Kyosho links) and two 12.6 mm long threaded rods from a T-Rex head linkage set. You can see the new links and pushrods in this picture, going from the end of the washout lever up to the pitch mixing levers:
With those links in place, the collective is buttery-smooth, positive, and has absolutely no slop anywhere. Bravo Kyosho (just make it so I don't have to use T-Rex parts in the future....).
The new TR hub is a monster improvement over the original hub. The new hub now has a couple of shanks on which the TR grip bearings fit:
In the original TR hub, the grip bearings were supported by the cap screw that also held the grip in place. Now, the new bearings (and you need the new BRG020O parts for this new hub) fit on that shank. The bolt that holds the grips in place simply does that, it no longer supports the bearings as well. Much more like the feathering spindle arrangement. I couldn't find the needed bearings at RC Heliworks (Chris knows about this, as well as the solution), or at Kyosho America (Dwight knows about this, is working on it, and also knows my solution). My solution? I bought a set of four 4 x 8 x 2 mm open, flangeless bearings from Boca Bearings. A set of four (I happened to get stainless races and ceramic balls) set me back about $28. That's what the list price would be on the same parts from Kyosho. The new bearings ought to be here in a couple more days. Then I can finish the assembly.
The XP has a new TR bellcrank, as well. Nicely supported by bushings, using a steel ball instead of a pin to move the slider back and forth. Again, buttery-smooth in operation.
One more Uh-Oh, however. I tried to put the plastic ball link ends on my new TR pushrod. To my dismay, the threaded portion of the rod I purchased happens to be too small in diameter. Instead of threading neatly into the shank of the plastic links, the rod simply plugs into the hole! This is a manufacturing defect. I've let Chris at RC Heliworks know, as well as Dwight. Between the two of them, I hope to not only get a better part, but to get the stock of bad parts purged before many others end up with a useless part. In the meantime, I've contemplated either using CA or JB Weld to make up the pushrod so I can finish the heli when those bearings arrive.
Here's a shot of the parts I got from RC Heliworks for the upgrade:
A shot before starting the conversion:
Part-way through dismantling the old...
And in with the new:
And a close-up of the new head and swashplate:
I should have this conversion completed this week sometime, and maybe be able to get out and at least hover and fly in my driveway. I'll let you know more about performance as I get a chance to fly it.
Overall, my impression of the XP is that Kyosho has really listened to its customers. All of the complaints about the original EP400 I listed in this thread about a year ago have been addressed in the XP design, and the implementation has been carried out very well. A couple of places where Kyosho might have done a little more homework is in the fit of the popular micro servos (that interference with the collective lever) and the fit of the plastic ball links on the end of the washout levers (more clearance needed, or different, thinner links in that location). A manufacturing defect (incorrectly threaded TR pushrod) needs to be fixed, and stock purged of the bad parts.
Kyosho America needs to stock a few more parts (and make them available to shops like RC Heliworks) to support the XP -- particularly 2 x 6 and 2 x 10 binding head, self-tapping screws and the 4 x 8 x 2 open, flangeless bearings. Dwight is aware of these parts shortages, and is working with Kyosho to get them in stock state side.
Stay tuned for flying updates as they come available.
Dave |
