Jump to content
Sign in to follow this  
Skip

Slermalling

Recommended Posts

Skip

I was noticing some advice being given elsewhere about using thermal lift and thought I would like to contribute some of my limited experience to the topic, just not on that site. I've put it here as I fly slope and use thermals to get me out of trouble on the odd occasion and the advice was given with regard to slope flyers not ever using thermal lift.

One piece of advice that made me want to pipe up was 'to fly slow enough to recognise the tell tail signs of lift'.

I quite strongly disagree with this and in my limited experience it is much easier to recognise a thermal when you hit it at speed. Secondly, the last thing I want to be doing is pootling around on the edge of a stall hoping that my plane will miraculously rise. You can search a much larger area at speed and the amazing thing about gliders is that they are much more efficient (don't know if that is technically true) at keeping a shallow glide angle at speed (it just may not LOOK like it).

Another thing I try to do is think about the topography and landmarks of the place. Thermals are air warmed by the ground staying on the ground until they 'pop' off.

At the Wrecker, that is normally out to the north and away from the slope quite a way.

On Mickeys they seem to stay off the slope and travel up the valley.

At Mickeys West they seem to go to the bowl to the left.

Anyway, thermal lift at a slope is amazing and playing with it from height is a great confidence builder as trying to find it for the first time when you NEED it is quite scary and often ends in a long walk with a bin bag.

I am not very experienced with slermal lift so would like to know if I am passing on incorrect advice and would also appreciate other's input.

Looking forward to some reply's

Share this post


Link to post
Share on other sites
Spoons

Most gliders will thermal providing that you fly them smooth and fast enough to make the airfoil section work.

The key to it is keep the model moving at a speed thats fast enough to generate lift across the wing, but not too fast that the model zooms across the sky.

You want the model to react to any slight updraft by either speeding up to indicate more energy, lift a wing or raise the tail.

Flying the model too slow will result in the model stalling (IE Dropping a wing, or mushing along tail down.)

With a wee bit of air speed (I know that this is counter intuitive) but this will get the model flying.

If you have the ability to set a wee bit of camber then set around 3 - 5mm of down across the wing.

This will cause the nose to pitch up and the model to slow (Sometimes) so you may need to add in some down to lower the nose and get the model flying again.

When all slope lift has been completely exhausted either hug the ridge or fly out away from the slope, dont panic !

Get the model moving and look around for any tail tail signs that there maybe lift (Birds, fluffy white clouds or the air warming up where your standing)

Thermals come in streaks so if you feel some warm air around then there is a thermal.

Push out from the slope and get the model flying.

The keep every turn away from the slope as to not fly through the same air twice, cos if it was no good flying through it then it will be no good if you turn back into it.

Keep the speed consistent with the model flying (The model wont simply drop out of the sky as gliders have a glide angle thats very shallow).

Turn away from the slope and then level the wings and fly back to the other side of the slope and repeat.

Dont panic and keep calm and fly as smooth as possible, look for the model to gain energy and speed up, the wing to kick up or the tail to rise.

The nice thing about thermals is that if the wind isnt blowing to fast there not going to head down wind at a million miles and hour and will more then likely be in the same place you found them.

If the left wing picks up the take a nice positive turn into the wing that pick up and continue round the circle, feeling where the model picks up speed or rises.

Try to extend the turn towards the area of the lift by flying straight for a while and then continue the circle round.

Then once around the circle asses if the model rose up or stayed where it was or lost height a wee bit.

If it stayed or rose then take another circle, if it fell continue to fly along the ridge turning smoothly way from the slope into clean air and back along the ridge.

If you get a bubble that the model sits in and doesnt go down or up, stick with it as it could potentially go at anytime.

Look out for sh1te hawks forming up around the model and follow them if possible (However they do tend to mock you.)

Important factors:-

  • Keep the model flying fast enough for the wing to work no tail down dragging its ar5e.
  • Look for birds and see if they flap through or simply soar, there could be a bubble
  • Little fluffy clouds with circular cloud foams to one side with nice black/dark bottoms
  • Changes in speed of the model, more speed or energy, tail lifting or wing popping up to say hello

I cant write down all of the things that I use to find thermals as you have to suck it and see and practice.

Flying a model with a higher wing load will just give you a higher forward speed in the seek mode to prevent stalling.

Dont panic and never fly in the same air twice, ie turn away from the slope and up wind, unless there is a certain section of lift.

Its harder to find lift if there is a lot of wind on the slope, due to the thermals moving down wind very fast.

Hope this helps.

If anyone else has any ideas that they use to find thermals please post here.

Cheers

Jon

Share this post


Link to post
Share on other sites
Woodstock

One piece of advice that made me want to pipe up was 'to fly slow enough to recognise the tell tail signs of lift'.

I quite strongly disagree with this and in my limited experience it is much easier to recognise a thermal when you hit it at speed. Secondly, the last thing I want to be doing is pootling around on the edge of a stall hoping that my plane will miraculously rise. You can search a much larger area at speed and the amazing thing about gliders is that they are much more efficient (don't know if that is technically true) at keeping a shallow glide angle at speed (it just may not LOOK like it).

+1! I've heard similar "advice" whispered at slopes, and really had to get a grip on myself so as not to be rude ...

Share this post


Link to post
Share on other sites
Phil.Taylor

Good thread starter there

The thing that many slope flyers dont understand in light slope conditions is the thermal lift/sink cycle - which you notice as periods of wind, with lulls in between. Simply put, in the lulls there may be a thermal out in front of the slope - so fly out to meet it. When the wind picks up, its too late, the thermal is now behind the slope - and you'll be launching into sink - and probably heading down, down...

Phil.

Share this post


Link to post
Share on other sites
Skip

Thanks Jon, I see you have clarified the slow enough bit from the other thread :clap:

Share this post


Link to post
Share on other sites
Skip

I can also understand peoples reluctance to keep the model flying fast and heading away from the slope (especially the Wrecker) and the only way they understand is if they see it for themselves or just do it.

Share this post


Link to post
Share on other sites
Spoons

The wrecker is a lovely site to fly with thermal lift alone, big huge open space with loads of flat boggy fields and houses at the bottom, oh and that road, plenty of thermal generators there.

Looks daunting but is a nice place to fly.

Share this post


Link to post
Share on other sites
slope_dragon_x

I guess that we're talking about slermalling with a modern moulded glider here? The advice for a traditional built up RES could be different.

Modern sections are thin and don't like to fly slowly (as has been mentioned). Anyone new to thermalling will be tempted to lug on the elevator, which as we've said is wrong. It slows the model and can bring the wing to a stall. Easier said than done to keep the model motoring of course.

There does come a time when I try to get the model to "hang on in there" and that is when the model is approaching the zone where finding lift is unlikely. Which brings us to local knowledge. That is something that needs to be gained through experience (preferably when there is lift about) or before launching by talking to local experienced pilots. Once launched then expert advice is just chaff and best ignored.

One thing that I have recently noticed that I do when seeking lift, is to be constantly testing feedback through the controls. That means the model has to be "flown" and not just settle into it's best glide angle. There is a fine line between testing the response and over controlling, but again that comes down to experience.

Back to commom misconceptions...... It's surprising how many inexperienced fliers think that "thermal flap" is a magic setting for escaping sink. I only ever use flap for slermalling when I know the model is in lift.

And finally.... as I may have mentioned before.... modern mouldies do not have to be flown slow and flat in a thermal bubble. Once I've felt a thermal I will often try to get the model on edge and "pump" the elevator. If the bubble is tight, then the model dips in and out of the bubble and it's surprising how much energy can be won (DS I think).

  • Like 1

Share this post


Link to post
Share on other sites
Skip

I am yet to engage the 'flick the switch' part of my flying brain. That would be part of the reason I won't be in a hurry to get to an F3B meet. Too many switches and settings. I use one switch to link my ailerons to my rudder so that I can launch right handed with confidence as a mode 1 flyer. And I have tried to use flaps on F3F launches (with zero success) and have always been more successful keeping a clean wing.

One day I want to do an F3F run right out in front of the slope in a thermal and see how it goes.

I remember one day on the Wrecker (ugh .... not THAT slope again), Adam being goaded into launching into a massive thermal with the wind-o-meter reading no-nada. Very effective peer pressure was applied. Actually it was almost bullying.

His time was amazing though.

Share this post


Link to post
Share on other sites
Spoons

Yes local knowledge can help, but learning how to read the air is a dead sure way to be sure at every site.

The 1st time I flew at upton I flew a ten minute slot out easy, simply by knowing how to read the air.

Experience is the only way to ensure that you end up thermalling effectively.

Learn how to read the air and then learn how to make use of the lift you have.

Learn to move the model around and pick up bits of lift and bounce from thermal to thermal.

Generally if you thermal on a slope or a flat field the principal is identical.

As Chris says, use thermal flap once you have hooked into a decent bit of lift.

J

Share this post


Link to post
Share on other sites
Woodstock

Read the air? Do you mean by way of watching / sensing the way the plane reacts?

Share this post


Link to post
Share on other sites
Skip

Read the air? Do you mean by way of watching / sensing the way the plane reacts?

I think you have to be able to read the area to make an educated guess as to which way to go and THEN be able to read the way your plane reacts.

Thermals get warmed at ground level, then get triggered to rise by a change in terrain like the end of a road or a change in the type of vegetation and move with the wind (being wind an all :) )

I think that is all part of what Jon was getting at :confused:

Share this post


Link to post
Share on other sites
Phil.Taylor

OK - time for another post...

This stuff about "dont fly slowly" needs some clarification

For thermalling - and "slermalling" (which I take to mean very light wind on a slope, with thermals coming through) - you need to know 2x flight speed settings - and you may want to set them up on your elevator trim (or flight modes). "Minimum sink" speed is close to the stall speed - and as its name suggests, you will sink at a minimum speed, or stay up longest - thats useful for "hanging in there". If you fly any slower / closer to the stall, you will come down faster - and may get into trouble with actual stalls, spins, tip stalls etc. The other speed is best L/D ratio, which is a bit faster than minimum sink - this is for flying the maximum distance for a given height - pretty useful for "ranging out" in front of the slope to search for thermals. Now - if there is still some wind to content with, then you will want to fly faster again to get "out front" to where the thermals are (hopefully!)

OK?

As for moldies flying different cos they have thinner wings, sorry - the same rules apply for whatever type of glider - all the way up to full size, where this type of stuff is better understood. The main difference is weight / wing loading - where a lightly loaded plane will stall at a slower speed, so you can fly it slower anyway. So, float around with you old floater or DLG, or get a move on by ballasting up your F3F ship (honest!) or flying that big heavy scale jobbie (got one now)

have fun - and nobody has commented on my previous post about lift / sink cycles? - to me, its the single most important thing you need to know about "slermal" flying.

Phil.

Share this post


Link to post
Share on other sites
Skip

I guess I might have misunderstood what slermalling meant. My understanding of it was thermalling from a slope, not using thermals on the slope.

I was thinking about commenting on your cycle post Phil, but this topic is turning into the Skip chat to himself topic again.

Seeing as I'm typing again anyway, I'll comment on it now if you like :D

The lift/sink cycle can catch you out fairly hard. I've flown an F3F course that was half in thermal lift and half in really aggressive sink for a few legs. Very confusing for my little brain to deal with.

Can't you pretend you have two different flight modes with the elevator? push down a iddy bit for fast and pull back a tad for slow.

Stooging around at minimum sink is likely to lead a less-experienced pilot to make an error and lose a LOT of height through a stall especially as we don't have the advantage of feel and that annoying stall buzzer thing that real planes have.

Share this post


Link to post
Share on other sites
Phil.Taylor

I guess I might have misunderstood what slermalling meant. My understanding of it was thermalling from a slope, not using thermals on the slope.

erm - hope I'm on the same page - same thing? - slermal - slope and thermal?

(which is well different from the F3F usage - where "a massive thermal came through" has an entirely different meaning)

the way I set up for "slermal" is to trim the elevator close to minimum sink - so it flies "hands off" - then push forward to gain speed to move out from the slope, or to get out of sink - fast.

Oh - and re. your original post - if the plane is happily flying "hands off" at minimum sink - and it just happens to fly straight into lift, then the nose will lift & it will seem like its starting to stall - which is what someone probably meant about "signalling lift".

Phil.

Share this post


Link to post
Share on other sites
Skip

Sorry Phil, I thought that's what you meant by 'thermals coming through',

For thermalling - and "slermalling" (which I take to mean very light wind on a slope, with thermals coming through

as in F3F.

I was more referring to searching for lift away from the slope

Share this post


Link to post
Share on other sites
Phil.Taylor

Sorry Phil, I thought that's what you meant by 'thermals coming through', as in F3F.

I was more referring to searching for lift away from the slope

yep - thats what I'm talking about too - searching for lift "out front" away from the slope

when the wind drops off - thats the time to chuck it out there & go find the thermal out front - if you dare!

Phil.

anyhow - time for bed & dreaming about summer thermalling ! :)

Share this post


Link to post
Share on other sites
Dave Elam

There's something extremely satisfying about launching off the top of a slope when there's no wind and catching a big thermal. It does make life a little less scary though if you do have an emergency land out option in case those birds were just having a laugh!

Share this post


Link to post
Share on other sites
Spoons

Thermalling from a flat field and from a slope are the same thing.

From a slope you dont need expensive launch equipment to get the height, as your already standing at the top of an effing great big hill.

Todays modern mouldies do need to fly, so I feel flying at near stall is not always the best thing to do, get the model moving, but not screaming and then fly looking for lift.

Lets no confuse people with techno talk that not everyone understands.

Keep it simple, fly to get the wing working and never fly in the same air twice.

J

Share this post


Link to post
Share on other sites
thermaldoctor

I would suggest the best speed to fly at will depend on how active the sky is and how quickly it's cycling.

Certainly in an active sky it makes sense to fly at the airframes best L/D. Anything more than that is not productive unless flying through areas of sink or to an area of known lift. In less active skies or if the air is slow cycling then flying at minimum sink may be better.

There is a big difference between flying so slowly it stalls and flying at minimum sink ;)

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.