RCM&E Dec 2018 - Ruckus Review Update

[Shaun Walsh]

1 minute ago, Stuart Z said:

You’ll need to pack the trailing edge, not the leading edge.  A couple of incidence meters would be useful.  My Super 60 had a similar problem and as engine adjust was awkward the tail plane incidence was changed.  Not such an easy fix on a Ruckus.  Do you know someone that has the same plane so that you can compare.  Incidence meters will help.  
S

Either way will work, over the top of the leading edge of the wing or over the top of the tailplane trailing edge.

[Nigel Heather]

4 minutes ago, Stuart Z said:

You’ll need to pack the trailing edge, not the leading edge.  A couple of incidence meters would be useful.  My Super 60 had a similar problem and as engine adjust was awkward the tail plane incidence was changed.  Not such an easy fix on a Ruckus.  Do you know someone that has the same plane so that you can compare.  Incidence meters will help.  
S

No, I’m the only one with one, regretting buying it to be honest.  I’ll keep tinkering but there is only so much valuable time I’m prepared to waste on it - there’s a good chance it’ll just end up in the tip - certainly won’t be buying another Max Thrust product, has been full of disappointments from the start.

Edited August 18 by Nigel Heather

[Stuart Z]

It’s a shame, it’s a good flying fairly aerobatic plane and lots of fun. It’s worth finding out what’s wrong. 
 

S

[Peter Jenkins]

1 hour ago, Shaun Walsh said:

As the Ruckus is a low wing model, shouldn't you pack the leading edge to reduce the incidence?

Sorry was confusing it with the Riot!  Yes, the LE should be packed to reduce the incidence.

[Peter Jenkins]

16 minutes ago, Stuart Z said:

You’ll need to pack the trailing edge, not the leading edge.  A couple of incidence meters would be useful.  My Super 60 had a similar problem and as engine adjust was awkward the tail plane incidence was changed.  Not such an easy fix on a Ruckus.  Do you know someone that has the same plane so that you can compare.  Incidence meters will help.  
S

Sorry Stuart Z you are incorrect in your statement.  I confused the Ruckus with the Riot.  For  low wing aircraft to reduce incidence, which is what I was trying to suggest to Nigel, you do need to pack the LE.  If you pack the TE for a low winger you will increase the incidence which is not what Nigel wants.  Although, by the sound of his last post it's all academic anyway!

[Nigel Heather]

17 minutes ago, Peter Jenkins said:

Sorry Stuart Z you are incorrect in your statement.  I confused the Ruckus with the Riot.  For  low wing aircraft to reduce incidence, which is what I was trying to suggest to Nigel, you do need to pack the LE.  If you pack the TE for a low winger you will increase the incidence which is not what Nigel wants.  Although, by the sound of his last post it's all academic anyway!

Not academic yet, prepared to try some more stuff, just that it will get to the point where I decide I am doing more fiddling than flying.

 

And yes I am pretty irritated that I am even having to do this for an ARTF foam model - I expect them to work out of the box.

[Stuart Z]

Given that this model is moulded in wing and tail slots I suspect any wing packing will not solve it.  Checking the incidences will at least eliminate any production lines errors. Never seen a Ruckus fly that badly.  Therefore a thorough check of the basics is called for.  

[GrumpyGnome]

If it's mushy and unresponsive at low throttle, and climbs (balloons) when throttle is added, it sounds to me like an incidence issue - not c of g or thrustline.

 

As well as looking at the wing, check the fuselage for bana-ness - a very shallow U would give too much 'up'; and check tail incidence in the 'slot' - can that be packed?  

 

I don't have a foam Ruckus but do have a wooden one - flies great when it's in one piece. Doesn't fly well once it's been through a Sycamore.........

[Peter Jenkins]

Incidence and thrust line are two sides of the same coin.  I used an increase in incidence as I couldn't use more down thrust on my F3A aerobatic machine.  It works fine by the way.  Cured a pitch to canopy on a vertical up line.

[GrumpyGnome]

You're far more experienced at this aero stuff than I am, but if there is an excessive positive or negative incidence between tailplane and wing, that's going to be masked but not cured by changing thrustline....... Don't F3A machines have adjustable incidences for this reason ?

[Nigel Heather]

1 hour ago, GrumpyGnome said:

If it's mushy and unresponsive at low throttle, and climbs (balloons) when throttle is added

 

This is exactly what it is doing.

[Peter Jenkins]

They do GG and some have adjustable tail planes that that' just to set the elevator flush with the tail plane once you have completed trimming.  Remember that we are talking about a balance of forces that are generated by the motor, wing lift and tail lift or more normally negative lift or a downward force.  Once you get all those sorted out then the aircraft behaves as it should.  Obviously, good design should mean that these factors are close to being correct so we, the user, only need to tweak them a little bit.  But, I guess "Friday afternoon" examples exist and Nigel might have one!

 

The relationship between the TP and wing is much debated and is called decalage.  When you have an elevator involved, it doesn't matter if it's out by a degree or so as the elevator trim takes care of that.  Making adjustments so that the aircraft will travel vertically upwards, hands off, is where playing with down/up thrust and wing incidence comes into it.  In a vertical upline, the wing should not be producing lift but the tail plane will still be producing the balancing down force to balance the nose down pitch of the wing assuming the CG is in front of the centre of pressure i.e. a stable situation and the resolved motor up/down thrust.  

 

  On my current aircraft, the TP was fixed so you just carried whatever elevator trim was needed and zeroed out the servo arm to its mid position by adjusting the linkage.  The easy way to do that is to use a turnbuckle pushrod as that gives infinite variation.  Of course, we're not talking a large amount of elevator deflection here unlike that on my Stampe where a good deal of down elevator is required for S&L flying.  What that needed was a TP mounted with more positive incidence rather than the 0 deg has been designed into it.

 

As I say, it's all a matter of balancing the forces acting on your model so that changes in motor thrust don't produce significant up or down pitch when the motor power is altered.

 

That having been said, I can remember being checked out on a Cessna 172 and being told to set up a full flap landing and then to overshoot.  The nose up pitch on application of full power was quite interesting!  The check out pilot told me that there had been the odd fatality when a lightly built female pilot was flying the aircraft and was unaware of this characteristic and didn't have the strength to push the control yoke forwards to prevent a stall.  They then put in electric trim with a trim switch on the control yoke!  Many full size aircraft do have such characteristics but we don't need to put up with them in models as we can design them out.

[Nigel Heather]

Remember we are talking about a mass-produced, cheap(ish), foam plane here, not a precision F3A aircraft.

 

I'm not expecting perfection, but I did expect it to fly reasonably well out of the box provided that it had been assembled correctly.

 

I have just carefully inspected the build, well to be precise, inspected for the third time, but just in case.

 

The tailplane fits into a slot in the fuselage - this is fitting perfectly, so if it is wrong it is down to manufacturing.

 

Likewise, the wing sets on the bottom of the fuselage and again that looks like a very good fit, pretty flush where the fuselage and wing meet with no overly large or uneven gaps.  So again, if that is wrong it down to the manufacturing.

 

I don't have an incidence meter - I'll put a call out to the club members to see if they have one - but I don't know what I should be looking for even if I do manage to get hold of one.

 

 

Finally, in terms of packing - do I need to pack the trailing edge or the lead edge - it's a low wing plane so packing will push the packed edge closer to the ground

[Stuart Z]

Nigel

All the foregoing has been a useful discussion but your plane would be difficult to adjust and still look good.

 

If it has been assembled from new and is assembled per the instructions, I don't see that you should need to go further than a call to Century UK.  As said these are good planes that fly well, not the most refined in construction but pretty hard to assemble wrong.  A few screws and an ally wing joiner rod.  The wing and tail fit as per the moulded wing seat / tail plane slots.  A call to Century seems the next step. 

[Learner]

How does it fly inverted and did you fly it before taking the weights out?

[GrumpyGnome]

Packing the wing will certainly be noticeable. Packing the tailplane less so - I don't know if it's attached by glue, or screws into plastic - the latter would make it easier to adjust the tailplane incidence.

 

53 minutes ago, Nigel Heather said:

Remember we are talking about a mass-produced, cheap(ish), foam plane here, not a precision F3A aircraft.

 

I'm not expecting perfection, but I did expect it to fly reasonably well out of the box provided that it had been assembled correctly.

 

I have just carefully inspected the build, well to be precise, inspected for the third time, but just in case.

 

The tailplane fits into a slot in the fuselage - this is fitting perfectly, so if it is wrong it is down to manufacturing.

 

Likewise, the wing sets on the bottom of the fuselage and again that looks like a very good fit, pretty flush where the fuselage and wing meet with no overly large or uneven gaps.  So again, if that is wrong it down to the manufacturing.

 

I don't have an incidence meter - I'll put a call out to the club members to see if they have one - but I don't know what I should be looking for even if I do manage to get hold of one.

 

Finally, in terms of packing - do I need to pack the trailing edge or the lead edge - it's a low wing plane so packing will push the packed edge closer to the ground

 

Yes, it's not an F3A plane but it should definitely fly out of the box.

 

Everyone has their own way of trimming an aircraft, and Peter is definitely more accurate than I am. But what I would do is.....

 

1. Get it in the air and try to establish if the cofg is correct - my rough and ready hack flying check consists of the dive test, and some inverted flight. If not as you like, adjust it

2. I'll then trim so it glides how I want - descending as shallowly as possible whilst maintaining good control.  If you find you need to add lots of up/down elevator trim, I'd say an incidence is wrong (you may have a bad moulding...)

3. I'll then check the thrustline.  I like my models to climb gently on increasing throttle.  If it's stays level, that's fine for me. If it has a strong pull up or down, I'll adjust the thrustline.

 

The comments about ballooning suggest too much wing incidence, so you'd want to decrease this by adding packing between the wing leading edge and fuselage - my wooden Ruckus would need some surgery to the wing retention 'lug' to achieve this....

 

Ringing Century before hacking at the airframe sounds sensible.

[Peter Jenkins]

Just to manage your expectation of.an F3A aircraft, they do not plug together out of the box.  There is a lot of work needed to get them into the air when the fun of trimming then starts.  Quite often, there are no instructions either!  So, I quite agree with Nigel's expectations of a modern mass produced product in that it should fly better than he has experienced but CG position does majorly affect the way the aircraft flies together with control throws being set to avoid twitchiness.

[Stuart Z]

On 13/08/2024 at 10:34, Nigel Heather said:

 

The stated CoG range is 80mm to 100mm from the leading edge, mine is balancing at 90mm.

 

[Nigel Heather]

1 hour ago, GrumpyGnome said:

 

 

1. Get it in the air and try to establish if the cofg is correct - my rough and ready hack flying check consists of the dive test, and some inverted flight. If not as you like, adjust it

2. I'll then trim so it glides how I want - descending as shallowly as possible whilst maintaining good control.  If you find you need to add lots of up/down elevator trim, I'd say an incidence is wrong (you may have a bad moulding...)

3. I'll then check the thrustline.  I like my models to climb gently on increasing throttle.  If it's stays level, that's fine for me. If it has a strong pull up or down, I'll adjust the thrustline.

 

 

25 minutes ago, Peter Jenkins said:

Just to manage your expectation of.an F3A aircraft, they do not plug together out of the box.  There is a lot of work needed to get them into the air when the fun of trimming then starts.  Quite often, there are no instructions either!  So, I quite agree with Nigel's expectations of a modern mass produced product in that it should fly better than he has experienced but CG position does majorly affect the way the aircraft flies together with control throws being set to avoid twitchiness.

 

All reasonable textbook suggestions I am sure.  But in reality .....

 

My short flights with this have left my pulse racing and my arms shaking.  For me, it is a challenge to keep the thing in the air, it is one big panic to keep it under control and to bring it down.

 

With any sort of throttle it climbs quickly into the clouds, at minimum throttle it is quite mushy and difficult to control in a different way.

 

My flights have been made in panic, I certainly do not feel at any time I could do some inverted flight - I'm not that comfortable flying inverted with an aircraft that flies well.

 

 

But I am becoming a little puzzled with the comments about CoG - to date the advice and guidance has been 'it's not the CoG' so I haven't played around with it other than to check it falls within the manufacturer's stated range.  One of my first questions was whether to push the CoG forward and I was simply told in chorus that it wasn't the CoG.

 

So going back to issue, the stated range for the CoG is 80-100mm, mine is set at 90mm, is it worth moving it forward to see if that makes any difference? 

[PatMc]

Ermm, isn't the effect of the motor thrust angle WRT the wing incidence ?

I.e. reducing the wing incidence is automaticaly reducing the motor's down thrust. 

[Stuart Z]

I don’t think it will cause major issues so well worth going to the front of the CofG range 

[GrumpyGnome]

1 hour ago, PatMc said:

Ermm, isn't the effect of the motor thrust angle WRT the wing incidence ?

I.e. reducing the wing incidence is automaticaly reducing the motor's down thrust. 

As Peter J said earlier, it is a balance between the thrustline, and incidences of the wing and tailplane......

[PatMc]

14 minutes ago, GrumpyGnome said:

As Peter J said earlier, it is a balance between the thrustline, and incidences of the wing and tailplane......

Well I think he got that wrong.

 

[PatMc]

On 16/08/2019 at 00:15, Mike Freeman said:

Hi Jeff,

Sorry to hear you are having troubles with your Ruckus.

I think your 3000mAh packs may be too heavy. I find the best CG location is 105mm back from the LE - a lot more than your 80mm!! I found a bit of differential on the ailerons helped the roll rate too. Here is the relevant bit from my review.....

Over the next few flights I tweaked the set up to suit a more aerobatic flying style. I swapped the Rx for a 6-channel version and assigned each wing servo to a separate channel so I could introduce a little differential. I finally settled on a CG location of 105mm from the leading edge (just behind the recommended maximum) and surface throws of:

 

Aileron 25mm up & 20mm down

Elevator 15mm each way

Rudder 35mm each way

 

With these settings and 20% expo dialled in I had the best of both worlds: Nice easy flying around neutral yet more exciting aerobatics with the sticks in the corners. All this and STILL that insanely slow flying speed is possible – amazing! The greater throws improved the aerobatic performance enormously with snappier rolls and super tight loops easily achieved.

 

The rearward CG makes the Ruckus almost pitch neutral which means it stays in a dive when the nose is pushed forward, there is just a gentle recovery to level flight when the sticks are released. Moving the CG any further back causes the Ruckus to stay in a dive or even tuck under which some may find disconcerting. Inverted flight requires only an occasional dab of forward pressure to hold level flight and inverted loops are no problem (as long as the LiPo pack is well strapped in!)

I recon you'd benefit from shifting the CG further back which should help reduce the power zoom you mention. I think I added a bit of down thrust and right thrust to mine after a while but I don't recall it being too far out out of the box.

Also, the 11x5.5 prop is more suitable for a 4S set up. A 3S pack needs a 12x6 for the best results.

I hope that helps and gets your Ruckus behaving properly. I'm still enjoying mine - a 3S 2200mAh pack and a 12x6 are just right for sports aerobatics - it won't quite climb vertical but does OK. Maybe the name makes us expect too much but, for a sports aerobatic Hack it does pretty well!

Cheers

Mike

I think Mike Freeman's post on page one of this thread gives the likely answer to the problem. A further forward cg would make the problem worse.

Also it's quite possible that the tailplane/wing incidence relationship is not as uniformaly accurate during manufacture as we'd like, so some elevator trim might need tweaking.    

[Peter Jenkins]

52 minutes ago, PatMc said:

Well I think he got that wrong.

 

In what way PatMc?