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Landing sequence for Dudek ReAction/Synthesis


gazza_c

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Well done that man! Thats what i like to read regarding my reaction and landing! I seem to be getting on alright but my few early sessions i seem to come in to fast and skid(luckily on feet,not cage) I think what i was doing is coming in to land, i start to apply the brakes slightly or too much and end up running out of travel :lol: Im getting better the more im out there doing it! cheers 8)

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Clive,

Thanks for the post it’s cleared up a misconception on my part; I thought the technique was to bury the brakes at 2m! :oops:

There’s another bit in the Synthisis manual on the subject of spot landings:

“If the landing field is not big enough and you have to land on the spot we advise that you set the trimmers in the red area. It will increase lift coefficient of the wing simultaneously decreasing its sink rate and speed.

Such an action is especially important when flying with high surface loading”.

I think that I understand the point that they’re making, i.e. small field therefore not enough room for the “bleed off” as described by Clive so the wing is trimmed to produce more lift and a slower landing.

What confuses me is why you wouldn’t want to land like that all of the time, slow and on the spot certainly appeals to me!

What’s the point that they’re making about high surface loadings?

Regards.

Togsie

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What confuses me is why you wouldn’t want to land like that all of the time, slow and on the spot certainly appeals to me!

I wonder if landing in a strongish wind would point toward landing on a faster trim setting?

Afterthought: Ooops, just re-read Clives post, he mentions surface wind strength. :wink:

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Clive,

thanks for the reply, the penny has now dropped and I understand.

I think part of the problem was that I’ve been watching too many old videos and I’d formed the impression that a good landing was a slow landing. Explained in the way that you have it all makes perfect sense.

Hopefully I’ll get to put the theory into practice sometime soon.

Regards.

Togsie.

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Just to recapp Clive....

The relationship between angle of incidence and angle of attack is fairly pivotal here.

So - your trimmers set your angle of incidence (AOI) which, in a wing with no other form of pitch control, defines what angle of attack (motor shut down) your wing will fly at. Every time you set your trimmers, you are therefore telling the wing what angle of attack you wish it to fly at, and therefore the mean speed at which you wish to fly (again, referring here to gliding - engine off).

Still air - Set up for a low speed/high lift approach.

With a surface wind running, there is potentail for gusts and therefore speed loss on the approach. Setting the trimmers for flight at a reduced AOI means that a higher airspeed will be flown during the approach (low angle of incidence therefore low angle of attack = higher airspeed).

So with higher surface winds, use settings that produce higher airspeed; no dis-benefit here as low groundspeed results from the higher surface wind. Another positive, gust protection provided and guaranteed penetration into wind; less chance of being blown backward.

A thought ~ Use all available means and controls to fly safely...

Notes

Angle of incidence (AOI) ~ the angle that is set between reference horizontal and the wing's chord line.

Mechanically adjustable by use of the trimmers on a paramotor/glider wing.

DI6G1.jpg

Angle of attack (AOA) ~ the angle between the oncoming airflow and the chord line of the wing.

Adjusted by pitch control directly and indirectly with a paraglider by use of the trimmers (that is the difficult one to get your head around, by setting the angle of incidence with the trimmers you are influencing the angle of attack that will result - ie: the glider will stabilize in its glide at an angle of attack that the angle of incidence dictates.)

airfoil-aero.jpg

As you know I am a PPG newbie Clive, does the above tally with your thinking?

Running through this stuff helps me and perhaps others as well.

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...The trimmers do ultimately change the angle of attack and our geometry setup with the thrust line being so far away from the wing also has a big impact which we should also be mindful of on the climb out on full power with big thrust motors, as the motor can swing forward and up and hang on its own prop which in turn can drag the wing behind it with excessive angle of attack, the airspeed will drop of quickly and the whole lot will drop out the sky! Thrust is an absolute must for braking away from the ground but it is then prudent to back the revs of a little to climb out gently...

Great post Clive. I think it's also important to realise that high thrust motors at full power swing you far enough forward that a component of thrust is now actually relieving some of the pilot and motor weight. This in effect reduces the wing loading and can make you more susceptable to risk of collapse. This is why some people use the 60-65% theory for static thrust.

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  • 3 months later...

This is a very informative post and as a relatively new flyer I'd just like to double check something...

When I'm free flying without a motor the lack of forward thrust is going to reduce the angle of attack (right?) and as a result I'm going to fly fast and lose height more quickly (yes?). I was flying at the weekend and most people with dedicated free flying wings were finding it far easier to stay up/gain height than me - of course this could have been a lack of skill on my part but some of those flying had just the same level of experience.

This being the case, should I then pull the trim tabs down further past the 0 (zero) point to give me a more acceptable free flying profile?

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