View Full Version : Parkzone Decathlon

08-09-2005, 08:25 AM
I wanted a "trunk rat" so picked one of these up...

I can’t see how this or the PZ Cub (flown both) can be called “beginner” planes. This is one of the most prone-to-auger-in planes I have ever owned! Its only saving grace is that it bounces very well. So far I have gotten rid of “the nut” under the cowl, reduced the down thrust (big difference) and gone to a GWS 9070 prop. These changes make the Decath flyable… but still not what I would classify as a beginners plane.

08-09-2005, 02:54 PM
I found that it was fairly easy to fly, but at high altitudes it was dificult to see direction.

08-10-2005, 05:28 AM
Maybe my friend and I got two bad planes, but they both have the same problems.

I can bring my GWS T-Moth in low and slow for a pinpoint landing, but in its stock form my Decath had to be dove in fast, power off, or it would snap violently.

After checking it out, I found the Decath to be nose heavy, with too much down thrust and bad incidences. The wing is a great example. Holding the plane up by the wing so that the struts are tight it has wash-in, the exact opposite of what is needed for stable flight. By just getting rid of the extra nose weight and about 3° of the down-thrust changed my planes flight characteristics dramatically. It can now be brought in under power and flared to a smooth landing. It still snaps when under power (and pressure on the wing) so next is figuring out how to lock in about an 1/8” of wash-out (so the inner part of the wing stalls before the tips).

08-11-2005, 02:46 AM
I do agree with you that it had to be brought down fairly fast, or faster than what most would expect. just a heads up we got um to fly in the back yrd because we live on a gulf course, after about 3 weeks of flying nearly 2 times a day averaging 17-20 min flights the motor decided it was not going to work any more. so look for this to possible happen in the near future. Also I dont know what you level of flying is, whats easy to fly for you may be hard to fly to me n vice versa...... on the landings what i would do is chop the throttle and circle above, pushing the nose down to stop the stall or the spin because there is not a lot of throw there to correct from a spin if unexpected...... but i would then easy back on the stick and settle her in..... no high alfa landing in this bird...... you almost have to keep the nose below the center line of the tale until tuch down is a second a way.....i did the same things you did, ie the nut in the nose.. are you trying to stiffen up the wing struts?

08-11-2005, 03:50 AM
Fast is not the problem with my plane… unstable is more the word I would use. I flew my first RC plane in 1980, and crashed my first E-Powered one in ’81. I call myself an aging novice. I fly to relax so have never gotten into real high speed or 3D… But, I do build and have become quite proficient in properly setting up and balancing planes so they fly as best as the design allows.

The points that I made about the PZD are accurate observations about MY Decaths problems as I bought it. As these are undoubtedly mass-produced by non-flyers, the inequities of my plane may not raise their ugly head in other PZDs. The upside of this is that, so far, I have been able to make great improvements in the Decaths flight characteristics with the minor changes I listed. As for the struts, I am hoping to replace them completely with either balsa or carbon fiber struts that will force washout into the wing tips.

08-11-2005, 03:26 PM
Hi guys, I agree that this isn't a beginners plane, but neither does Parkzone advertise it as such (as far as I know). Raht, my Dad bought himself one of these after a 20year lay-off and is loving it. We agree that it isn't as stable as a slow-stick or other slow flyer, but that's not the point. Ít is a scalish slowish, relatively easy to fly rtf aeroplane.

Its very good at what it is meant to do, which is flying around for fun without assembly at a low cost.


08-11-2005, 05:09 PM
I never thoght aboutthe carbon fibar struts, that is a good idea....
I am going to go ahead and do the same.
you can cheack with Gene at troybuiltmodels.com for the carbon fiber material.

If i offended you in anyway i appologize as it was not my intent. I am putting a rimfire brushless motor in mine and am going to upgrade to lipo and possible ad the forth chanel in there. good luck and if you find anything else upgrade wise let us know.

08-12-2005, 07:30 AM
INCOMMING... Absolutely no apology needed as I took no offence in your post, actually I thought it interesting. You obviously are a good pilot if you can fly (and even harder) land a stock PZD. I should have mentioned that I so value your experiences with the PZD that I have printed out your note and am going to try out your suggestions the next time Tony and I get together to fly ours.

I think I will go to the CF struts; my problem is that even though we have three (sorta) hobby stores in our little town of 4000, not one caters to park flyers more then having aerobirds and a few "crossover" parts. I will have to wait until I can get to a "real" HS which is about two hours away to buy the CF.

CRISTIE I think you missed my main theme... Which is, NOT that the PZD is a bad plane, but rather that it HAS problems that CAN be fixed with relatively minor changes. And, that these changes turn loose its true potential to be a truly great little plane. Aside from that, my mention about it being a "beginners" plane comes from how they are marketed in out local hobby stores... In one, (in the next town) there is a whole shelf of the PZ Cubs and Decaths next to the Aerobirds. When talking to the owner, he told me, that because the PZ planes come complete and ready to fly for less then the cost of a regular 4 ch radio, they are the "kind" of plane that a total newbie would be "willing" to buy.

I too enjoy flying my PZD... but, my understanding of RC planes led me to find ways to improve this one and I felt it important enough to share this information...

It is SO COOL that you and your Dad are flying together! I raised three kids and not one is the least bit interested in RC... Hmmm, All is not lost though as I have two grandkids that I can work on!

08-27-2005, 04:15 AM
I put some washout on my PZD by using a hair dryer, a shaped wood block and a little elbow grease. I took it from approximately four inches from the end of the wing. The tip is about four degrees out from the root. It seemed to help on slow flight. I think the carbon struts are a good idea. I may do that when I do my aileron mod.

Also, switching to a 9x4.7 prop made a huge difference in performance.