Having trouble flying inverted

[GrumpyGnome]

Yep, the W4 foamy will certainly do inverted. I'd still agree that 20ft is pretty unforgiving and is probably best attempted once inverted flight is pretty much second nature - i.e. you can fly s&l, full circuits, rolls, loops (inside and out), other loop/roll combinations inverted.   

 

All my planes climb slightly (right way up) with increased throttle - all sport planes or semi-scale warbirds. All my planes need a degree of 'down' when inverted - some need quite a lot. The only exception is my foamy indoor 3d Yak, which is just about neutral in all axis, with no mixing.

 

 

[MattyB]

8 hours ago, Mike T said:

I disagree a bit with the 'neutral CG' notion.  If, in order to fly inverted you have to put a little, continuous forward pressure on the stick to remain S&L, its a constant reminder that, in this scenario, 'forward = up'.

 

I fly a foamy 'F3A' practice aircraft which is CG neutral and (to me) flying inverted seems uncomfortable if I'm not leaning on the stick a bit.

 

1 hour ago, John Stainforth said:

I agree with you here. All the models I have flown inverted, even those with the CG quite far back, have required a little push on the elevator stick. I say "push, push, push" to myself when inverted. If I get too close to the ground I just push harder. That works well for me.

Let me clarify… By “neutral CG”, what I really meant was “not an extremely forward CG” which, let’s face it, an awful lot of Sunday sport flyers trim their models at. This is often because the instructions suggest very conservative positions. Trimmed correctly I’d expect to need just a tiny nudge of down on something like a Wot 4 or Acrowot when inverted at cruise throttle. Anything more than a quarter stick and the balance point is too far forward; time to reach for that trim weight!

Edited June 23, 2023 by MattyB

[Philip Lewis 3]

11 minutes ago, MattyB said:

 

Let me clarify… By “neutral CG”, what I really meant was “not an extremely forward CG” which, let’s face it, an awful lot of Sunday sport flyers trim their models at. This is often because the instructions suggest very conservative positions. Trimmed correctly I’d expect to need just a tiny nudge of down on something like a Wot 4 or Acrowot when inverted at cruise throttle. Anything more than a quarter stick and the balance point is too far forward; time to reach for that trim weight!

I'd agree with that, if you have trimmed your plane to fly straight and level then it will by definition have some up elevator to so so, how much depends on your C of G, in competition aerobats there are some that adjust trim for a straight downline rather than for straight and level flight but then you need to holding as much up when level as down when inverted. My competition planes have a downline switch in of about 3% to fly vertically straight down with no pull out to the canopy, so flying inverted would need about 6% down elevator which is hardly a push and more like breathing on the sticks.

 

A typical assessment method of an aerobat would be to fly a 45 deg upline and roll inverted, if it plumets for the ground the c of g is too far forward, it should do a very gradual parabola towards the ground, if it climbs the c of g is too far back, this doesn't really apply to lifting wings though which will always need a fair amount of down elevator to fly inverted.  

 

Most club flyers as Matty said fly with a way far forward C of G because for the reasons stated, they also in my experience tend to fly with far more movement than they actually need on al of the control surfaces.

 

Ron's method of a loop then fly straight out the top is textbook coaching, if you are nervous I would suggest putting your finger across the back of the stick at first, that way you can't "pull" into the ground you can only push up. 

[PDB]

22 minutes ago, Philip Lewis 3 said:

Most club flyers as Matty said fly with a way far forward C of G because for the reasons stated, they also in my experience tend to fly with far more movement than they actually need on al of the control surfaces.

 

As a beginner I followed the CG setting as per the manual for my Boomerang, now realising it was well forward for obvious reasons which made learning easier. 

 

The first time I inverted the model it made a dive for the ground and on pushing the elevator stick I ran out of travel.

 

After reading Peter's book I understood the problem and gradually moved the CG back until only a small amount of down on the elevator was required.

 

This is an issue I guess affect a lot of newbies. 

Edited June 23, 2023 by PDB

[Martin Harris - Moderator]

Another factor in early inverted flying attempts is lateral stability.  If you are flying a typical trainer - high or shoulder wing with dihedral - as soon as you go inverted you’re effectively flying a low wing model with anhedral!

 

The result is that not only are you typically pushing a fair amount of down to counteract the effects of a “safe” C of G and the loss of lift from a flat bottomed or asymmetrical wing section but your well behaved trainer suddenly makes you work very hard at keeping the wings level. 
 

All good reasons to learn inverted flight at height.  At least the roll instability will help you take the correct escape action of rolling out - unlike the lucky escape I witnessed a couple of days ago when a clubmate, unused to scale models, found his Tiger Moth unexpectedly inverted at low level after falling off an attempted stall turn and bunted out of it - the ground/hedge were horribly close as the model failed to respond like his usual sporty aerobatic models!

[paul devereux]

Thanks for all the responses and advice, I have read and will re-read it all again later as I struggle with this. I have also spent a bit of time on Phoenix, not sure entirely profitably as the Wot 4 trainer they have is sluggish and won't fly inverted, whereas the wot 4 foam-E is lively. Perhaps one of the acrobatic models in Phoenix is more accurate for the foam-E. The wing section is pictured. It will fly upside down easily with a bit of down elevator- it's just I can't do it! I failed again this morning- went into a loop, held it inverted for a short while, tried to roll out but then became a bit disorientated and thought I was going to crash it so just whizzed about a bit until the time was up.

One problem is the plane is quite small (49 inch span) so it gets far away quite quickly- my eyesight is good, but I'm in my 60s so it isn't perfect.

What I have been practising is half-loops and then half rolls each direction to help me get used to recovering from inverted flight.

Another question I have is- I have learned about dual rates, but I still like to fly on high rates- the plane is pretty lively but well-controllable. Am I right in thinking that learning with a lot of movement is better than learning with just  a little (in the sense of, if you can fly it like that, you'll have no trouble with a tamer plane?) Or is that erroneous thinking?

[Ron Gray]

7 minutes ago, paul devereux said:

but I still like to fly on high rates- the plane is pretty lively but well-controllable.

In all probability that is not helping you. I had a foamie WOT4 for several years and only flew it on high rates when I wanted to loon around, most of the time it was set on low rates. I would suggest trying it on low rates and practice big half loops that will end up with you getting a lot of height and when held inverted off the top do not fly it too fast. With sufficient height you can either roll out of inverted or just pull the elevator to complete the other half of the loop ( with the throttle back on the down).

[paul devereux]

31 minutes ago, Ron Gray said:

In all probability that is not helping you. I had a foamie WOT4 for several years and only flew it on high rates when I wanted to loon around, most of the time it was set on low rates. I would suggest trying it on low rates and practice big half loops that will end up with you getting a lot of height and when held inverted off the top do not fly it too fast. With sufficient height you can either roll out of inverted or just pull the elevator to complete the other half of the loop ( with the throttle back on the down).

How low? I know it is an impossible question, but generally how low should the rates be reduced in the first instance to make a plane more docile? 25% and see how it feels with that?

Edited June 24, 2023 by paul devereux

[leccyflyer]

3 hours ago, paul devereux said:

Thanks for all the responses and advice, I have read and will re-read it all again later as I struggle with this. I have also spent a bit of time on Phoenix, not sure entirely profitably as the Wot 4 trainer they have is sluggish and won't fly inverted, whereas the wot 4 foam-E is lively. Perhaps one of the acrobatic models in Phoenix is more accurate for the foam-E. The wing section is pictured. It will fly upside down easily with a bit of down elevator- it's just I can't do it! I failed again this morning- went into a loop, held it inverted for a short while, tried to roll out but then became a bit disorientated and thought I was going to crash it so just whizzed about a bit until the time was up.

One problem is the plane is quite small (49 inch span) so it gets far away quite quickly- my eyesight is good, but I'm in my 60s so it isn't perfect.

What I have been practising is half-loops and then half rolls each direction to help me get used to recovering from inverted flight.

Another question I have is- I have learned about dual rates, but I still like to fly on high rates- the plane is pretty lively but well-controllable. Am I right in thinking that learning with a lot of movement is better than learning with just  a little (in the sense of, if you can fly it like that, you'll have no trouble with a tamer plane?) Or is that erroneous thinking?

Yes, it's erroneous thinking. You should set your rates at what you are comfortable with to fly that particular model in the manner that you want to fly it and get completely happy that you can make the model do what you want to do. There's no advantage, or direct translation, in having a very twitchy aeroplane and mastering that, in order that a less twitchy aeroplane will be easier to fly at a later date.

[leccyflyer]

2 hours ago, paul devereux said:

How low? I know it is an impossible question, but generally how low should the rates be reduced in the first instance to make a plane more docile? 25% and see how it feels with that?

What does it say in the manual about the recommended throws for the control surfaces? That ought to be a decent starting point - set your low rates in accordance with the lower end of the recommended throws.

[leccyflyer]

Here's what the manual says

 

For initial flights, we recommend the following control throws - each measured at the widest point of the surface:

Elevator: 9~15mm up 9~15mm down

Rudder:45mm left 45mm right

Ailerons: 6~9mm up 6~9mm down

 

So for low rates, set the rate to give the lower end of the range of throws - 9mm up and down for elevator , 6mm up and down for aileron.

Edited June 24, 2023 by leccyflyer

[RICHARD WILLS]

If you move to Australia , it will come naturally . I have been led to believe everything is upside down there.

Does holding the tranny upside down help ?

Just a thought ...

[leccyflyer]

In one of those life imitates art thing I've just totalled my venerable Wot-4 Foam -E, flying inverted - it wasn't less than 20 feet when I started out, but it tried it's best to get to -20 feet in short order. I'd been having shortened flights with a particular battery pack, but it would charge and balance okay, so I set the timer for 4 minutes, with the intention of a short flight, land, then check the voltage/cell.

 

Anyway, remembering this thread I was mooching around inverted and the model was requiring increasing amounts of down elevator to keep from diving. Then it didn't matter how much down I gave it, she tucked right under and went in at about 45 degrees, proper hard. One of the guys said that the motor was still running in the wreck, but it wasn't, since I hit throttle cut as soon as I crashed. When I got to the model the motor-like noise was the elevator servo going mad, at full down elevator, chundering away, beyond where you would like to see a servo doing it's thing, but trying to go further.

 

Damage was limited to the entire airframe, which is already in the bin. The motor mount looked like it had been crafted by Salvador Dali, the fuselage was in five pieces, it turns out even the carbon wing spar was a mass of splinters just outside the fuselage. This one didn't need marinating for a few days to see it it was repairable. 

 

The model was one that I'd repaired after recovering it from a clubmate's estate sale. It's had a long, hard life, as an all weather hack, so owed me nothing. Not sure that I'll be rushing out to get another though.

[paul devereux]

This morning, fortified by the posts here, I set off with high hopes and my only two Lipos. Partial success with the first flight! Flew inverted about 5 yards, gave a bit too much down, it climbed and I rolled upright. Took off with my remaining battery hoping to build on this success when the Tx battery warning sounded so I landed straight away!

I must admit, it is fun. @leccyflyer- Sorry to hear of your mishap.

Edited June 25, 2023 by paul devereux

[leccyflyer]

No worries.

 

All the salvageable bits removed from the Wot-4 Foam-E checked out and the elevator servo has stripped gears, which in these days of cheap mini servos like that means being consigned to spares - I suspect that they are Ripmax servos, so not something that I already have spares for. The motor seems okay, prop adaptor might be slightly bent, motor mount heavily bent, ESC, battery and the other three servos are all fine. Flimsy control linkages salvaged for possibly use on future wee models.

 

I hadn't appreciated that the EPO wing is actually hollow, with a thick EPO spar, containing a carbon tube reinforcement - shattered and splintered where the wing had torn. I legerated some thin sheets of EPO about 8-10mm thick, which could prove useful in future repairs of such models. The airframe, such as it is, plus the shattered cowl are all in the bin.

[Engine Doctor]

I trim my models with a slight downwards trim , just a coupke of clicks ,so normal level flight requires  pulling a tiny bit of up in . When inverted there is no need pushing stick forward. Another benefit is it will prevent a model fly away if control is lost for any reason in addition to failsafe .

Works for me but we all have our favourite method. 

[leccyflyer]

Different strokes, 🙂 since I mostly fly my 42-48" span funfighter "warbirds" I have mine set up so that they naturally pull out when diving towards the ground to beat up the field. If I let go of the sticks they will pull up on their own - this prevents me from just flying into the ground whilst I'm muttering "takka-takka-takka" under my breath.

[paul devereux]

1 hour ago, leccyflyer said:

Different strokes, 🙂 since I mostly fly my 42-48" span funfighter "warbirds" I have mine set up so that they naturally pull out when diving towards the ground to beat up the field. If I let go of the sticks they will pull up on their own - this prevents me from just flying into the ground whilst I'm muttering "takka-takka-takka" under my breath.

Is that a gyro/sensor type of thing, like the "virtual fence", I think it is called, on the tiny models? I've never worked out how those things work, they can't be GPS sensitive, or are they?

[MattyB]

10 minutes ago, paul devereux said:

Is that a gyro/sensor type of thing, like the "virtual fence", I think it is called, on the tiny models? I've never worked out how those things work, they can't be GPS sensitive, or are they?

No, a positive pitch up as described is pitch primarily a function of CG and elevator trim position. 

[leccyflyer]

29 minutes ago, paul devereux said:

Is that a gyro/sensor type of thing, like the "virtual fence", I think it is called, on the tiny models? I've never worked out how those things work, they can't be GPS sensitive, or are they?

No, it's just the way that the trims are set up, you'd have to actively put in even more down to fly the model into the ground.

[Shaun Walsh]

8 hours ago, RICHARD WILLS said:

If you move to Australia , it will come naturally . I have been led to believe everything is upside down there.

Does holding the tranny upside down help ?

Just a thought ...

I had enormous trouble flying inverted until someone said not to do handstands on the flight line.

[paul devereux]

Well. I managed this morning to fly straight and level inverted first one way and then the next! I didn’t push my luck, after that I just flew about a bit till the timer sounded. It was just a confidence thing, I think- next I’ll try doing a circle.

(Thanks to all for all the comments and help, even the ones that said stuff like I should try flying in Australia, or standing on my head, lol!)

I haven’t done too bad learning solo I think- this time last year I tried flying my Wot 4 foam–E for the first time- lost control in seconds and had to repair a split wing and replace a shattered fus.

Then I got a HZ Champ and practised and practised. I’m lucky to have some pasture land to learn in peace and quiet, and also the Champ is so light it can’t be damaged if the throttle is closed- it floats down like a feather. It is a shame looking back I didn’t know it was tail heavy; learning on it would have been so much easier. Still, it taught me about orientation.

So a good day today, I hope anyone else flying today also has a good day!

[Maurice Dyer]

Yep, all these tips and tricks sound plausible and help, I expect.

The one hint,tips or any other thing people cannot teach is this;Practice, practice and probably more practice........

[Rich Griff]

And to realise that at first you wiggle about, crawl, learn to walk, on to running and then train for a marathon.

 

Progress....

[Rich Griff]

How I envy you Paul.

 

A flying site ten minutes walk away...

 

I used to fly from a large beach ten minutes walk away from where I lived at the time.

 

Large open beach, lovely air...flat smooth surface...

 

I got inverted flying to a very low level. I mentioned thinking about fitting an extra undercarriage on top of the wing of the shadow, a wot4 look alike 40 glow powered.

 

One time I went just a tad too low inverted. The up command ( left stick forward ) caused the tallish rudder to contact the sand, no way out of that one, even more power would not have helped.  Ah well, throttle fully closed and down trimmed ( quick old style trims not bleepy bleep slow digital modern stuff ) to "land" upside down in the sand.

 

Walk home, no damage, clean engine, back flying next day....

 

I was very nearly up to b test standard back then.

 

Where I live presently every flying site other than under 250gram suitable sites, is a car drive away, even the sloping site.

 

Why oh why did I move, a four letter word, work !

 

Practise practise practice, explore the flight envelope but by bit. You will soon be doing inverted figure of eights from all directions except vertically perhaps, outside loops, even inverted, then steadily decrease hieght until you get to your 20 foot target, but no lower.

 

I know of no people 20foot high.

 

Is your site "private land" ?

 

Be aware that one day someone will wonder over to you and distract you, a danger !

 

Think about having a "look out" with you, or fly from fields centre area so on lookers remain on lookers, lookers from afar, outside the fence.

 

You can fly at a safe height so you can do a rapid look around in stages....mind you your flying electric, I'm used to soaring or ic for at least 12 minutes before I have to think about landing.

 

You do shout out LANDING even though no body is about don't you.

 

Hare and tourtoise...

 

Enjoy...

 

Ps seen mini and micro super plans on Oz....

Edited June 26, 2023 by john stones 1 - Moderator
Dumb predictive text and swearing, please don't.