HK ZLIN 50L 70 ic

[john stones 1 - Moderator]

Put a link on John if you can please

John

[jeff2wings]

Try Hobby King Zlin 50 (70 size ) in the search box

[john melia 1]

I've just read that thread jeff2wings, obviously it seems the 91 two stroke is not ideal, but unfortunately its the only engine i have spare so its going in. I'll beef up the front end as best i can, and then suppose just hope for the best. We'll see

[jeff2wings]

If I was fitting a 91 2 stroke , I think I would use something like a 14x6 three blade prop and a pitts type muffler ,Just Engines custom made one with extra baffles for my Moki 135 and v/effective it is to ,this will help tame any "excessive" excess of power ! BTW I have change the engine to a ASP 91 4stroke this is much better and no lead up front

[Glyn R]

 

I built mine with a Turnigy SK3 5065 I used a 5000mah 6s battery to get the nose heavier. The model is very aerobatic I have thought about swapping for an ASP91FS myself. I may fit my RCGF 15cc petrol with a Pitts. will fit nicely in the cowl.

Edited By Glyn R on 12/05/2014 22:57:04

Edited By Glyn R on 12/05/2014 22:59:20

[john melia 1]

Thats a two stroke in the pic aint it?

[john melia 1]

Can't i just throttle it down to keep the power within reasonable limits

[john stones 1 - Moderator]

I would think so John

I see you read Jeffs thread you just need a throttle, not a stop a go one

May pay to look at u/c as well, looks a nice model

John

[john melia 1]

Ok guys i'm in a bit of a dilemma at the moment so can i pose one final question regarding engine installation on this zlin 50L. Probably more orientated at you jeff2wings lol.

At present i have an ASP 61 in my jodel d120 which flies great, but the rudder authority is something to behold, i think its because the whole vertical stab moves as a rudder, which seems to make knife edges ect imposible.

Should i use the 61 for the zlin? Would this be more apprpriate than the 91 two stroke? Would the 61 give it good performance? Also as i dont have a manual where is the cg ? And would it be reccomended to reduce what the stated throws are in the manual , ( just read something about this while googling the zlin)

Edited By john melia 1 on 13/05/2014 08:36:34

[jeff2wings]

O.K. John , data first ,the stated ideal C.G. is 118 mm (4.6 in) behind the L.E. measured at the wing/fuselage seat this is best done with the model inverted of course ,elevator throw is stated as 55 mm each side of neutral ,rudder 85 mm each way and aileron 35 mm each way measured at wing root .Now these are the maximum throws for ‘3 D’ type flying and with 50-60 % expo are o.k. for experienced thumbs but I found the ailerons still a bit savage and would suggest only 20 mm each way with some expo to start with.

The 90 2s will be fine but the reason for concern is that in a dive with the throttle open, the 2 stroke will wind up a lot quicker than the 4 stroke and the airspeed could reach a point where airframe damage may result ,with a larger than normal prop this will reduce the max rpm ( and thus, power) again you can reduce the max throttle setting with the atv/end point on your transmitter ,I have done this with this plane as when I went to test fly it , the club had decided to lower the nose limit to 80 db ! And the only way I could do that was to have a maximum of 60 % throttle, still had power enough to climb out at a 50 deg angle though. hope this helps.

[john melia 1]

Brilliant thanks m8 much appreciated, i know what you mean about decibel limits, the local club i joined seem to be frowning upon ic in all its shapes and forms. They state a max engine size of 60 with standard silencer, yet they will still put a decibel meter on it and declare it too loud. They are always going on about how fantastic the electric revolution is........ But the point is i dont want to go electric, and i wont be forced to do so either. I have a h9 spitfirewith a 91 fs, which is equivalent to a 60 ts and seems to run quieter than a 60 ts, yet they wont allow it to fly. Anyway back to the zlin, i was thinking of a 14x6 prop, could i go bigger? Also i temporarily attatched the 91 ts to the firewall just to get some cg measurements, i measured 120mm back from leading edge by the fusalage, inverted the model and put it on my cg stand., and even with the 91 and battery rx pack balanced right up front it still was tail heavy, is this a trait with the zlin?

[Glyn R]

My Zlin has a 15x6 or a 14x7 3 blade.

[Glyn R]

HK Zlin 50L seems to have excessively rearward CG. The wing chord at the centre is 330 mm,the general guide for CG is about 30% this is 99mm back. I have been flying mine with the recommended 118mm and have found it very twitchy, I am about to add weight to the front to move the CG forward. Anyone else had this problem?