Don't test fly on a windy day - you'll probably regret it!

[Roger Jones 3]

Posted by Bonzo Moon on 30/01/2021 14:57:36:

Yes, no doubt true. Every time it dived I tried to fly it back with just a little throttle, and I think I had the orientation OK, but it just did it's own thing! It did appear that the throttle was doing it's own thing too, hence the crazy climbing. Anxiety does come into it too though, and eventually I knew I'd reached a point (and said it) where it was gone! Lessons learned.

I was quite pleased with that even model even if it was just a cheap build foamie. I'd put a lot of thought into the build too. Only a couple of days. I guess at least it wasn't something I'd spent weeks building in the traditional way in balsa with lovely covering etc. That would have been really gutting. I've seen videos from a guy on YouTube who builds beautiful jet airliners, and one of his crashed and burned in it's maiden.

Model planes can be small and model planes can be large. There is no such things as 'wind' to a plane in the air bur there are gusts.

Regardless of the size of the plane a higher wing loading will give you more inertia per unit area and the plane won't be disturbed by gusts so much. It's why some slope soarers (in particular) have bays to put weights in.

The airliner. If that was the video I saw fairly recently it was obvious it would happen. Too much time spent building highly detailed airborne 'dolls houses' and not enough air time.

[Piers Bowlan]

Posted by Roger Jones 3 on 31/01/2021 07:37:17:

Posted by Bonzo Moon on 30/01/2021 14:57:36:

Yes, no doubt true. Every time it dived I tried to fly it back with just a little throttle, and I think I had the orientation OK, but it just did it's own thing! It did appear that the throttle was doing it's own thing too, hence the crazy climbing. Anxiety does come into it too though, and eventually I knew I'd reached a point (and said it) where it was gone! Lessons learned.

I was quite pleased with that even model even if it was just a cheap build foamie. I'd put a lot of thought into the build too. Only a couple of days. I guess at least it wasn't something I'd spent weeks building in the traditional way in balsa with lovely covering etc. That would have been really gutting. I've seen videos from a guy on YouTube who builds beautiful jet airliners, and one of his crashed and burned in it's maiden.

Model planes can be small and model planes can be large. There is no such things as 'wind' to a plane in the air bur there are gusts.

Regardless of the size of the plane a higher wing loading will give you more inertia per unit area and the plane won't be disturbed by gusts so much. It's why some slope soarers (in particular) have bays to put weights in.

The airliner. If that was the video I saw fairly recently it was obvious it would happen. Too much time spent building highly detailed airborne 'dolls houses' and not enough air time.

Oh dear! Just when I thought we had rediscovered how to be nice to each other again 

Edited By Piers Bowlan on 31/01/2021 08:58:24

[SIMON CRAGG]

Posted by Piers Bowlan on 31/01/2021 08:57:32:

Posted by Roger Jones 3 on 31/01/2021 07:37:17:

Posted by Bonzo Moon on 30/01/2021 14:57:36:

Yes, no doubt true. Every time it dived I tried to fly it back with just a little throttle, and I think I had the orientation OK, but it just did it's own thing! It did appear that the throttle was doing it's own thing too, hence the crazy climbing. Anxiety does come into it too though, and eventually I knew I'd reached a point (and said it) where it was gone! Lessons learned.

I was quite pleased with that even model even if it was just a cheap build foamie. I'd put a lot of thought into the build too. Only a couple of days. I guess at least it wasn't something I'd spent weeks building in the traditional way in balsa with lovely covering etc. That would have been really gutting. I've seen videos from a guy on YouTube who builds beautiful jet airliners, and one of his crashed and burned in it's maiden.

Model planes can be small and model planes can be large. There is no such things as 'wind' to a plane in the air bur there are gusts.

Regardless of the size of the plane a higher wing loading will give you more inertia per unit area and the plane won't be disturbed by gusts so much. It's why some slope soarers (in particular) have bays to put weights in.

The airliner. If that was the video I saw fairly recently it was obvious it would happen. Too much time spent building highly detailed airborne 'dolls houses' and not enough air time.

Oh dear! Just when I thought we had rediscovered how to be nice to each other again

Edited By Piers Bowlan on 31/01/2021 08:58:24

Well said Piers, I thought everybody was supposed to be "kind" to each other at present?.

Ok, Bonzo dropped himself in the Doo-Doo a bit, and made it worse by innocently posting it on here.

I am pretty sure Bonzo is not a serial trouble making yob, and he has been very helpful to me with my version of his Vulcan.

The details have been picked over ad infinitum.

What is that saying?. "If you can't say anything nice, do not say anything at all"....very apt at the moment I would have thought.

As far as we know, nobody died and it didn't cause mayhem on the nearby road etc. etc.

Who has not made a similar doo-doo?. I know I have......many times.

Life is to short to try and score points off each other, let us just get on with building and having "Fun" with our fantastic hobby!.

Stay safe all.

[Roger Jones 3]

Posted by Piers Bowlan on 31/01/2021 08:57:32:

Posted by Roger Jones 3 on 31/01/2021 07:37:17:

Posted by Bonzo Moon on 30/01/2021 14:57:36:

Yes, no doubt true. Every time it dived I tried to fly it back with just a little throttle, and I think I had the orientation OK, but it just did it's own thing! It did appear that the throttle was doing it's own thing too, hence the crazy climbing. Anxiety does come into it too though, and eventually I knew I'd reached a point (and said it) where it was gone! Lessons learned.

I was quite pleased with that even model even if it was just a cheap build foamie. I'd put a lot of thought into the build too. Only a couple of days. I guess at least it wasn't something I'd spent weeks building in the traditional way in balsa with lovely covering etc. That would have been really gutting. I've seen videos from a guy on YouTube who builds beautiful jet airliners, and one of his crashed and burned in it's maiden.

Model planes can be small and model planes can be large. There is no such things as 'wind' to a plane in the air bur there are gusts.

Regardless of the size of the plane a higher wing loading will give you more inertia per unit area and the plane won't be disturbed by gusts so much. It's why some slope soarers (in particular) have bays to put weights in.

The airliner. If that was the video I saw fairly recently it was obvious it would happen. Too much time spent building highly detailed airborne 'dolls houses' and not enough air time.

Oh dear! Just when I thought we had rediscovered how to be nice to each other again

Edited By Piers Bowlan on 31/01/2021 08:58:24

What's 'not nice' about it? Human opinions don't alter truth.

Low, slow, turning, a far too high angle of bank for those conditions so it sideslips into the ground. I bet he used the ailerons to turn, not the rudder as he should have. That would have greatly reduced the angle of bank while still causing the turn,

There's a youtube video of a real B-52 doing exactly the same thing at an air display.. That he was going to stuff the B-52 in was obvious.

AND MY POST may help  prevent other modellers doing the same thing.

Edited By Roger Jones 3 on 31/01/2021 09:31:43

Edited By Roger Jones 3 on 31/01/2021 09:33:37

Edited By Roger Jones 3 on 31/01/2021 09:34:15

[Denis Watkins]

I am just happy with Bonzos' honesty with his truth, laying bare strengths and things to avoid.

It was a small " foamie " in wind with problems.

Support has been given, and we learn more from the issues.

[Roger Jones 3]

Posted by Denis Watkins on 31/01/2021 09:39:54:

I am just happy with Bonzos' honesty with his truth, laying bare strengths and things to avoid.

It was a small " foamie " in wind with problems.

Support has been given, and we learn more from the issues.

Yeah. I mostly build glow balsa/ply planes with 40 and up engines.

If nothing else this thread is tempting me to build a small foamy, maybe a delta as they tend to be crash resistant, to fly in m back garden.

[leccyflyer]

When all's said and done and notwithstanding the dubious premise for the flight in the first place, t was a piece of foamboard weighing the square root of nowt getting away downwind on a windy day- four pages of detailed analysis of the model set up, the control inputs used and the possible aerodynamic causes seems a little bit over the top.

[J D 8]

A good number of years ago I made a foam board [ house insulation board ] model more or less in the layout of a paper dart. Power was Irvine 20, controls throttle and elevon's. Radio used had nothing fancy like expo.

It was pretty fast in a straight line, tight turns killed the speed and as you may expect the roll rate was silly.

It was when flying slowly nose high things got interesting. With the model at angled at about 45 degrees to the ground and the motor going flat out it would fly around at walking pace quite easely maintaining height, even roll control was not to touchy.

Problem came when you wanted to return to normal flight. Full down elevator would result in only a small reduction of the angle of flight and carry on it would slowly loosing height. There was only two ways to escape, just carry on with a little less power until down at ground level and cut the power and flop down. Or if you had plenty of altitude at least 50 feet, cut the power and it would go into a tail slide and then flip into a nose down attitude. Then power up to gain speed and pull out. The end came when one day I failed to do this in time.

[Rich Griff]

Gosh, that's aerodynamic, glide angle of a lightening, which was something like 89 degrees dead stick ?

We are all learning and can take lessons from this such as:

A. When building the hull, replace the air with foam, that way it probably won't sink....dam wrong forum !

 

I will start again,

 

1. Make sure brain is in gear before opening gob.

 

2. Wear gloves and a hat on cold icey days. Cold can befuddal the brain, brrrrrrrr

 

3. A white or grey or silver model will vanish in a grey sky. Colour the model black as we rarely fly at night.

 

4. Right model for right conditions.

 

5. Principle of flight has not really changed, the thrust, drag, lift, weight plus sign etc.

 

5. Plate type wings are not the best aerodynamic aerofoil section, they tend to fly on the prop/thrust.

 

6. When in trouble, close the throttle so thrust reduced.

 

7. Fly within your capabilities.

 

8. A suitable flying site.

 

9. Flying close to, under and around HV power lines is a no brainer. Flying by any power lines including telephone lines is a no brainer.

 

10. Make sure you are fully legal, negligence or " I didn't know " or "I didn't realise" is no defence.

 

11. Servo glitching, don't fly at all untill you are completely satisfied radio gear is 100 per cent ok and reliable.

 

12. Always have enough fuel, plus some extra, for your expected flight. Don't mearly rely on "smart technology"

 

13. Covid, is your outing essential, don't do things cos you can, thing should I do that thing. Government administration says look them in the eye and say have I done everything I could and should do to help beat this virus, and, remember that nurse crying her eyes out in the car? I do.

 

Have I made mistakes in the past, dam right, but I luckily never lost a model, or lost control and crashed. A have made mistakes in landings and damaged ( yes a crash ) the model, but repaired them if possible.

 

We can all learn from this thread. Those who think they won't learn from this thread are a crash/accident waiting to happen.

Remember the slogan, safe flying is no accident ?

Maybe that slogan needs to come back. It has never left some of us. I even used it in gocarting job.

 

Stay safe out there and have a good day.

 

Feel free to add to the list, we can only learn.

Edited By Rich Griff on 31/01/2021 11:49:34

[Bonzo Moon]

Some interesting 'ideas' here that I feel I should respond to.

 

Model planes can be small and model planes can be large. There is no such things as 'wind' to a plane in the air but there are gusts.

As a qualified ocean yachtmaster with 70,000 miles and a paraglider pilot, paramotor pilot who has studied meteorology I can assure there is such a thing as 'wind' and it will affect an aircraft, whether a jumbo jet or a 300 gms model.

Try taking off 'down wind'?

I agree the plane doesn't know or feel how strong the wind is, or feel it unless it's turbulent, but it affects its progress over the terrain. Ground speed. Even an airliner in the jetstream will make a faster Atlantic crossing on a good day with a good tail wind. Every time this model climbed higher the 'wind speed' was increasing because of 'wind gradient' and it was being carried away faster and faster from me downwind. The WIND, whether laminar or gusting,(ie occasionally blowing at higher speed than the average wind strength) , was carrying it away.

Sorry, but a few definitions

1 wind,  the perceptible natural movement of the air, especially in the form of a current of air blowing from a particular direction.

2. wind speed, the rate at which air is moving in a particular area

3 wind gradient,  the rate of increase of wind strength with unit increase in height above ground level.

4. Ground speed.  Ground speed is the horizontal speed of an aircraft relative to the Earth’s surface.

 

and finally ...

This made me chuckle a bit

Low, slow, turning, a far too high angle of bank for those conditions so it sideslips into the ground. I bet he used the ailerons to turn, not the rudder as he should have. That would have greatly reduced the angle of bank while still causing the turn,

I'm definitely not the best RC pilot on the planet (not that you know what my flying skills are like?)

but ...

you're dead right Roger, I didn't use rudder, it didn't have one, this model has elevons

 

A good list  Rich,

Definitely.  

4. Right model for right conditions.  

.... 

Just seen this.  Very interesting, and quite similar. Thanks.

Problem came when you wanted to return to normal flight. Full down elevator would result in only a small reduction of the angle of flight and carry on it would slowly loosing height. There was only two ways to escape, just carry on with a little less power until down at ground level and cut the power and flop down. Or if you had plenty of altitude at least 50 feet, cut the power and it would go into a tail slide and then flip into a nose down attitude. Then power up to gain speed and pull out. The end came when one day I failed to do this in time.

 

The never ending thread! 

Stay safe out there and have a good day.

 

 

 

Edited By Bonzo Moon on 31/01/2021 12:08:52

Edited By Bonzo Moon on 31/01/2021 12:13:02

Edited By Bonzo Moon on 31/01/2021 12:16:02

Edited By Bonzo Moon on 31/01/2021 12:19:51

Edited By Bonzo Moon on 31/01/2021 12:20:22

[Piers Bowlan]

Posted by leccyflyer on 31/01/2021 09:49:38:

When all's said and done and notwithstanding the dubious premise for the flight in the first place, t was a piece of foamboard weighing the square root of nowt getting away downwind on a windy day- four pages of detailed analysis of the model set up, the control inputs used and the possible aerodynamic causes seems a little bit over the top.

An OTT thread maybe but thanks to Bonzo for entertaining us with his video which prompted a bit of discussion. Lets face it with 'conventional models' grounded with clubs closed down, this provided a bit of light entertainment. I have nurtured a long held interest in tailless aircraft but not built a low aspect-ratio tailless model to date. Maybe I will give it a try now and practice some high-alpha slow speed flight in my back garden. Could be fun.

 

Edited By Piers Bowlan on 31/01/2021 12:32:02

[Rich Griff]

You must have a big back garden dude.

Not many flat calm days in this country, but we have a few.

Will you be able to fly within the confines of your garden, with all the CAA rules etc., but it may be a micromodel for all I know.

Micromodel more likely to be influenced by any breeze probably.

Anyways have fun and enjoy, but remember to cover the pool...oh there's an idea, indoor pool so waterborne take off and landing, yes !

Believe it or not but further up the valley well away from the power lines is a largish lake, mmmmm

And at the top of the valley, a reservoir, well out of the way of everybody apart from the he fishermen, and in the next valley, an even bigger lake.

I think I may need a rethink of flying site, what could go wrong !?

[Rich Griff]

I have seen and flown a model plane backwards, or appears to fly backwards from my point of view on the ground.

A negative ground speed, but good airflow speed over the wing, else it would fall out of the sky.

I am not having a go at you bonzo, but with all your knowledge and experience, you chose to fly a new unknown model that day.

One thing wrong, you can usually get away with it.

2 things wrong and you might get away with it.

3 things wrong, all mount up and result usually not getting away with it.

That's my experience, I strive to have nothing wrong, but as we know, doodoo happens like someone comes over to talk to you whilst you are flying your plane, or you miss hearing "LANDING DEAD STICK" just as you are turning onto onto finals...

[ron evans]

Like J D 8 , I have g lot of fun flying at high alpha circuits with this delta, although recovery to normal flight is ok if the power is eased on slowly. On one flight with the model far out, nose up and low down, I went to full power quickly and it went into a sort or hovering spin, I shut the power off and being low it landed without damage.

I've since done this at height and kept it under control (sometimes ) producing a sort of climbing spin.

If a wing climbs under power and the thrust line is zero, a little dowthrust will help, but the main cause is probably a forward C.G. needing more up elevon for level flight in cruise.Increase speed and the up becomes more effective and the model climbs.

I have a wing that climbed under power and I gradually moved the C,G. back until power on or off it would fly level. I had to reduce the throw in pitch, and in that trim there was no up elevon.

I did find that trim a bit wearing, the model went where it was pointed,. including straight down with no self recovery, so I moved the C.G. forward a little , and I live with the slight climb under power.

Ron

[Bonzo Moon]

I have seen and flown a model plane backwards, or appears to fly backwards from my point of view on the ground.

I've flown backwards on my paraglider, not a good place to be! Landed going backwards even. Best avoided. If the wind is picking up and you have not a lot of ground speed when flying it's time to get on the ground ASAP.

A pool in my garden? I wish. I do cover my little pond though Sod's Law that's where something would end up.

Roll on some decent weather and end of lockdown so we can all get out and fly again.

[Rich Griff]

All this talk if lakes for I'm me someone is going to say take up fishing, no no no.

Research " king of the fishes " on Chris Jagger's album called " Chris Jagger ", Mick's brother.

Good album well worth a listen 😎.

[Rich Griff]

Air speed over the wing is crucial, but yes, landing backwards in any plane is not good.

Back down the shed for me till I can't feel my fingers, about 29 mins even with gloves, it's cold today and snowing a bit. Out.

[Bonzo Moon]

Posted by ron evans on 31/01/2021 13:25:05:

Like J D 8 , I have g lot of fun flying at high alpha circuits with this delta, although recovery to normal flight is ok if the power is eased on slowly. On one flight with the model far out, nose up and low down, I went to full power quickly and it went into a sort or hovering spin, I shut the power off and being low it landed without damage.

I've since done this at height and kept it under control (sometimes ) producing a sort of climbing spin.

If a wing climbs under power and the thrust line is zero, a little dowthrust will help, but the main cause is probably a forward C.G. needing more up elevon for level flight in cruise.Increase speed and the up becomes more effective and the model climbs.

I have a wing that climbed under power and I gradually moved the C,G. back until power on or off it would fly level. I had to reduce the throw in pitch, and in that trim there was no up elevon.

I did find that trim a bit wearing, the model went where it was pointed,. including straight down with no self recovery, so I moved the C.G. forward a little , and I live with the slight climb under power.

Ron

 

Interesting. Deltas obviously have tricky aerodynamics.

Does it help if it's in pusher configuration?  I've built a couple and they fly well.

 

Edited By Bonzo Moon on 31/01/2021 14:00:17

Edited By Bonzo Moon on 31/01/2021 14:07:10

[ron evans]

Bonzo, this delta does have a strong torque reaction even though it's only a 5x5 prop.

A friend built one with a pusher and twin fins, and this one had little torque reaction but was harder to launch.

Ron

Edited By ron evans on 31/01/2021 14:37:20

[Stuphedd]

https://m.youtube.com/watch?v=r54gEr8r-BI&pbjreload=101

Bonzo has the right idea , this hobby is about having FUN, and these little light deltas are just the ticket

Just hope the above "link" works !!

Cheers

[J D 8]

Both deltas and flying wings have some advantages over conventional types in some parts of the flight envelope but they also have some disadvantages, one of these is control or the lack of when outside of normal flight regime. I was flying my Zaggi power [ it has a pretty hot set up ] at high speed when a small section of covering ballooned in the airflow and threw it into a spin. It was then rotating in a flat attitude and there was no way to recover to normal flight without a rudder Just cut power and it span all the way down to a soft landing.

Funny shaped aircraft are good fun though.

[Bonzo Moon]

Posted by Stuphedd on 31/01/2021 15:13:46:

https://m.youtube.com/watch?v=r54gEr8r-BI&pbjreload=101

Mako electric delta model plane

Bonzo has the right idea , this hobby is about having FUN, and these little light deltas are just the ticket

Just hope the above "link" works !!

Cheers

That looks great, very similar in fact to my lost RM1. I think I might try and lose one of those next

My Flight Test Versa wing , with my added nose on it flies really well. It's a heavy motor and the nose helped greatly in achieving the CoG, as the battery sits in there. I added an undercarriage too!

[Roger Jones 3]

Posted by Bonzo Moon on 31/01/2021 12:05:02:

Some interesting 'ideas' here that I feel I should respond to.

 

Model planes can be small and model planes can be large. There is no such things as 'wind' to a plane in the air but there are gusts.

As a qualified ocean yachtmaster with 70,000 miles and a paraglider pilot, paramotor pilot who has studied meteorology I can assure there is such a thing as 'wind' and it will affect an aircraft, whether a jumbo jet or a 300 gms model.

Try taking off 'down wind'?

I agree the plane doesn't know or feel how strong the wind is, or feel it unless it's turbulent, but it affects its progress over the terrain. Ground speed. Even an airliner in the jetstream will make a faster Atlantic crossing on a good day with a good tail wind. Every time this model climbed higher the 'wind speed' was increasing because of 'wind gradient' and it was being carried away faster and faster from me downwind. The WIND, whether laminar or gusting,(ie occasionally blowing at higher speed than the average wind strength) , was carrying it away.

Sorry, but a few definitions

1 wind, the perceptible natural movement of the air, especially in the form of a current of air blowing from a particular direction.

2. wind speed, the rate at which air is moving in a particular area

3 wind gradient, the rate of increase of wind strength with unit increase in height above ground level.

4. Ground speed. Ground speed is the horizontal speed of an aircraft relative to the Earth’s surface.

 

and finally ...

This made me chuckle a bit

Low, slow, turning, a far too high angle of bank for those conditions so it sideslips into the ground. I bet he used the ailerons to turn, not the rudder as he should have. That would have greatly reduced the angle of bank while still causing the turn,

I'm definitely not the best RC pilot on the planet (not that you know what my flying skills are like?)

but ...

you're dead right Roger, I didn't use rudder, it didn't have one, this model has elevons

.

.

.

.

The never ending thread!

Stay safe out there and have a good day.

 

 

 

 

This stuff is always coming up in model flying circles. Not so much in general aviation.

Of course wind exists, we all know that... . A surface vehicle, be it land or marine has a reference to the surface as it is attached to it via wheels, tracks, hull, keel, whatever. Even those new freak America's cup boats, via the foils.

Bur an aircraft isn't. it is totally 'unaware' of the ground. Leaving aside gusts and windshear It is flying in a 'block' of still air. That the 'block' is moving with reference to the ground is of no matter.

People don't seem to realise this, hence the modeller dreaded 'downwind turn' nonsense. 'Dreaded' because the modeller is trying to produce a constant  speed and/or symmetrical shapes with reference to the ground so ends up with a too slow airspeed.

Then we have 'downwind or 'upwind'.  Thst needs a reference. Upwind of the church, downwind of the tall tree  or the pilot, to the windward of the shore. An aircraft is unaware of all those things.

Takeoff  downwind? It just takes a longer runway is all,  the aircraft being unaware of groundspeed at all times. Do it a lot  you may wear the wheelbearings our but that's all. There are no aerodynamic effects (such as control blowback)once you have reached  the windspeed so are 'stationary' re the aircraft's only reference,

Edited By Roger Jones 3 on 31/01/2021 16:37:46

Edited By Roger Jones 3 on 31/01/2021 16:38:56

[ron evans]

When I upgraded my old Zagi to brushless / lipo there was a big increase in power and speed.

One hot day the model sat in the sun for a few hours before I flew it, and on a fast pass the wing fluttered and clapped hands.

Amazingly when it slowed up the wing went back into shape, and with partial control I got the model down in one piece with one horn broken.

It seems that the heat had softened the adhesive on the covering, and the extra speed caused the failure.

Of course the model had been designed for lower power brushed motors, and had no spars, so an easy fix to add top and bottom carbon rods, and no problem since.

Ron

[J D 8]

Hi Ron, After the incident related above some Rhino tape was added top and bottom, it's still flying.

John.