Parkzone Spares

[Erfolg]

I have a PZ Stinson Reliant.

Unfortunately the wing is in need of replacement. I have tried the Internet and Horizon Hobbies for a part, they appear to be now unavailable.

The model has now become almost unflyable, from a docile flies itself condition. The wing washout etc no longer being consistent.

The issue was most noticeable during take of, where a sudden turn and wing drop to the left, made this stage of flight an issue. Requiring a major input of right rudder, to correct direction, then a little later, aileron to lift the wing.

Unfortunately on Sunday it now is an issue when landing. Flying into a strong wind of at least 12 mph, with a ground speed of at least walking pace. It suddenly tip stalled at about 2-3 feet altitude (to the ground).

Since then I have been in search of a replacement wing. I cannot decide to fly it until completely wrecked, to retire it in the hope of some future miracle. Or are there other alternatives?

[MattyB]

They have been out of production for quite a few years now, so I'm afraid your only option is going to be build another wing for it - finding one in as new condition is highly unlikely. Maybe try using Depron with PVA/brown paper covering?

Edited By MattyB on 28/10/2016 14:53:25

[eflightray]

How about two sheets of Depron or foam board cut to the same profile and build a simple Armin type wing.

Ray.

[John Tee]

Silly question but whats an Armin wing look like?

John

[Phil 9]

that is a big problem with Horizon hobby models that never seems to be mentioned. there models seem to have a short production run and then they bring out a new design. Fantastic if you like variety but finding parts for a favourite older model soon becomes impossible

[Erfolg]

The wing is still in one piece as is the rest of the model.

I am reluctant to try and make a replacement on the grounds, I am not really sure why a pussy cat cat has turned into an unpredictable Tiger. PZ have done a good job on a very tapered wing, could I do as well, i do not think so.

I would need to take a lot of measurements of thickness, guess what airfoil has been used, plus the angles of the 0-0 line. I am not sure i have the inclination , the time, or skill.

Edited By Erfolg on 28/10/2016 18:40:35

[MattyB]

Posted by John Tee on 28/10/2016 17:40:52:

Silly question but whats an Armin wing look like?

John

One of these... Basically a crude foam wing that can be built flat and uses multiple sheets of packed foambard as a spar.

[Tim A]

Just searched all US suppliers I have used before for you Erflog, without success sorry.

This is a problem with a lot of suppliers of ARF's & RTF's as quickly as they announce a new model I think they must be planning to discontinue as well. Hobbyking are a prime example.

I assume the wing has lost its rigidity? Why not recess & glue some thin carbon rod on the underside to strengthen it, did this on a old EPO? Cessna 180 I have and it flew even better than before.

Regards Kiwkikanfli (When the weather improves).

[MattyB]

Posted by Erfolg on 28/10/2016 18:38:05:

The wing is still in one piece as is the rest of the model.

I am reluctant to try and make a replacement on the grounds, I am not really sure why a pussy cat cat has turned into an unpredictable Tiger. PZ have done a good job on a very tapered wing, could I do as well, i do not think so.

I would need to take a lot of measurements of thickness, guess what airfoil has been used, plus the angles of the 0-0 line. I am not sure i have the inclination , the time, or skill.

In that case you only have two real options - add a couple of degrees of reflex to both ailerons and see if that helps (you could add it in just to your landing/takeoff flight mode), or strip out all the electrics and install it in something similar like a Durafly Tundra or PZ Sport Cub.

[Erfolg]

The wing seems as stiff and strong as ever. It has been repaired, I can see that it is not perfect. Although the errors are not obvious either. It no longer just flies itself, it is now unpredictable, not suitable for a novice or me.

Thank you for your efforts from down under.

[John Tee]

MattyB. Thanks for that ,I'd not heard the term before. Long video will have a longer look later.

John

[IanR]

Contact Wheelspin Models - out-of-stock but still listed **LINK**

Ian

[Tim A]

Erflog, just another thought if as you say the wing is still as stiff as ever, what about the servos & linkages i.e. servo twitching in flight, loose or binding linkages, poor self centering etc?

Excuse me if you think I am trying to teach you to suck eggs!!

Regards Kiwikanfli

[Erfolg]

Kiwi

Nah! You can all teach me to suck eggs, If I knew the answers i would not have posted this thread.

I will try to evaluate what has changed with the wings geometry.

The model has suffered damage over the years, although it appears that the accumulative apparently minor) damage is now significant. Being Polypropylene it has been repaired using cyno in the past.

What is perhaps surprising is how PZ produced such a docile model, when the wing plan-form would indicate a bit of a beast,

[KiwiKid]

Hi Erfolg, just did a quick squiz of my sources and came up blank (like Kiwikanfli) with the exception of Atlanta Hobby:

**LINK**

Might be a bit of an expensive exercise getting it across the ditch. If you are interested at all I would suggest that you send them an e-mail to confirm, firstly, that they do, in fact, have a wing in stock and then to advise likely shipping cost. I have been dealing with this company for many years without problem. Payment is via Paypal.

[Denis Watkins]

Just three things Erfolg, that I have experienced similarly, that untamed a pussy cat. 1. An unnoticed change of C of G, where the weight moved back, the ballast had come loose. 2. The whole servo tray was detached cleanly, and all appeared OK, but it was sliding fore and aft. 3. I too thought my wing twist was the problem, but one horizontal stabiliser had cracked and was able to move under load. I do favour the loose tail scenario as this produced the biggest change in flight, as opposed to a twisted wing, that somehow can always be trimmer out to a steadier flight characteristic

[John Lee]

I ended up scrapping mine last year & stripping it for components. It had relatively minor damage after the tape holding the tailplane in position came loose resulting in uncommanded down elevator. I patched it up but it never flew the same.

[Engine Doctor]

If the model looks right with no obvious twists and both wings match then there surely must be another cause for the sudden change in behaviour . For it to behave that badly /unpredictably a wing would have to be seriously damaged or flexible . I would go down the route Dennis Watkins suggest and look at servos and their mountings, motor mounts/thrust line ,control fixings CG and lateral balance etc. These are more likely to cause the sudden unpredicted problems you describe if unsecure .

 

Edited By Engine Doctor on 29/10/2016 11:17:21

[Erfolg]

I have checked the CG, whilst checking the security of the Lipo, the servo mountings and linkages were also checked, last week. All was found to be in order.

The issues is wing related. That is why I decided to buy a new wing.

As it appears impossible to purchase new, I will look at the wing more carefully with a view to ascertain what has changed or is no longer symmetrical.

[Simon Chaddock]

Erfolg

Just thought but could the problem be due to wing no longer having the same stiffness left and right, although I have no idea how you could accurately test it.

With such a sharply tapered wing that in effect gives forward aerodynamic sweep, equal wing torsional stiffness is likely to be critical to achieve 'nice' flight characteristics.

[Pete B]

I've transposed the title and sub-heading to help anyone using the search function in future, Erf....

Pete