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Switching to electric gliders from fixed wing large scale electrics


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15 hours ago, Jonathan M said:

On a non-scale four-servo wing competition thermal glider the following is normal:

  • Flaps normally move as a proportion (say 50%) of aileron movement.
  • In Thermal Mode an equal amount of camber is applied to both flaps and ailerons.
  • In Cruise Mode both flaps and ailerons are flush with the wing root, i.e. in a neutral position.
  • In Speed Mode an equal amount of reflex is applied to both flaps and ailerons.
  • The amount of camber (say a few mm max) or reflex (just a mm or two) is normally specified by the designer/manufacturer as a starting point, then can be tweaked by the flier to suit their own flying style.
  • Selecting between flight modes is normally done using a 3-position switch, although some fliers like to then have the exact amount of Thermal Mode camber further adjustable via a slider (but only active when that mode is selected).

 

This is all good advice, but to be honest I would not bother with quattro flaps (the jargon name for mixing in your flaps with the ailerons) initially. You will have plenty of aileron effectiveness without it for the test flights, and a you need to be able to understand how much rudder to use in the turns initially without that additional variable IMO (as a beginner to high a/r gliders you may even decide you want a CAR - coupled aileron and rudder - mix , though I personally much prefer to do it with my thumbs!).

 

You can always add in quattro later as a scwitchable "Acro" flight mode, but for thermal and general cruising it's generally more efficient to do without it. 

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Quattro flaps is a step to far for me at the moment, Matty.  As you say and I agree, I think to start off with I will see how much rudder I need to feed in when turning using the current settings I have dialled in. As I have said before simplicity is key for me and to start with I prefer to manage with the two sticks on the TX to steer flight rather than scrabble around for various switches ?. The sophistication comes later I guess and I found Jonathan's explanations very helpful ?

 

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I took a look at the starboard wing again. I put a straight edge along the aileron and flap and they are perfectly straight After another close look at the wing it seems that the end section of the wing is out of alignment. What to do? I adjusted the working surfaces so that the flap, aileron were in a straight alignment to the root and just left the difference on the tip end. I don't know what the effect will be. Time will tell when I get her in the air.

IMG_0464.jpg

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Final bit of tidying up. I decided to add extension leads from the RX to the ailerons and flaps for connecting to the wing leads therefore keeping disturbance to the RX at a minimum when connecting up. Blue thread locker on all connections and secured the RX to the fuselage side with velcro. 

I secured the folding prop and ran the motor up at full chat for a short burst - all seems well there. Just need to get used to the routine of rigging for flight at the field .......

IMG_0468.jpg

Edited by Adrian Smith 1
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  • 3 months later...

https://www.youtube.com/watch?v=CBAP2TPGG_A

 

Well maiden day came and went in a disappointing fashion. I may well know lots about fixed wing aerobats, but I have lots to learn on flat field gliding. In my defence it's been about 15 years since I touched a glider and it might take a while to return to it again ?.

Here is a clip of my attempts to launch said glider. To launch a glider of this size probably requires two people as trying to heave it into the air with a throbbing motor while holding a TX is not in my skill set at the moment. Part of the problem is I was trying to take off at 1/2 throttle which was all I could stand given the ensuing balancing act. Plus the fact there wasn't much wind to help with lift. Anyway see what you make of it as I am sure there will be lots of helpful advice coming my way.........

Next flying session on Thursday will be a fixed wing aerobat though! 

IMG_0791.jpg

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Hi Adrian. On the plus side, it looks good and still seems to be in one piece. ?

 

It is not a particularly big glider, but the fuselage is fairly large to grip with one hand and the UC wheel seems to be in just the place I would like to hold it when launching, so that makes it difficult for you. If you can get some one to launch it for you for the maiden that might be a good idea. Once you have the confidence of knowing how it flies you can try self-launching again later.

 

A straight launch is often more important than a hard launch, so I have sometimes suggested practicing by throwing a broom handle or a piece of 2x2 timber till you can throw it straight and hard.

With some of my more powerful gliders (too much to hold at full power) I try to level it up with 2 hands then drop one hand to the Tx to hit full power as I throw with the other. If you are reasonably quick that will result in a level launch at full power which should help. Practice throwing the “broom handle” while manipulating the throttle like that to perfect the action before trying with the model ?.

 

It looks great so don’t give up.

 

Dick

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4 hours ago, Adrian Smith 1 said:

...Here is a clip of my attempts to launch said glider. To launch a glider of this size probably requires two people as trying to heave it into the air with a throbbing motor while holding a TX is not in my skill set at the moment. Part of the problem is I was trying to take off at 1/2 throttle which was all I could stand given the ensuing balancing act.

 

1 hour ago, Dickw said:

...It is not a particularly big glider, but the fuselage is fairly large to grip with one hand and the UC wheel seems to be in just the place I would like to hold it when launching, so that makes it difficult for you. If you can get some one to launch it for you for the maiden that might be a good idea. Once you have the confidence of knowing how it flies you can try self-launching again later.

 

Yes, I agree - modern scale glider fuselages with their mid mounted wings can be really hard to launch single handed, so get some help for the next one so you can launch on full power. Once it is trimmed you will find it much easier, especially once you are confident enough to launch then throttle up to full power.

 

The first launch did make it look like it might be a bit rearward in CG though - presumably you've double checked it is set at a reasonable (safe maiden) position?

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Sadly no helper is available as I am a solo flier. In hindsight I should have used my TX tray which has been collecting dust in the workshop. This would have made it easier. Something I will use next time. 

Yes Matty I did check the CoG before flight as per plan, but I agree it looks a bit suspicious and may be marked incorrectly. Something else to look at. 

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37 minutes ago, Adrian Smith 1 said:

Sadly no helper is available as I am a solo flier. In hindsight I should have used my TX tray which has been collecting dust in the workshop. This would have made it easier. Something I will use next time. 

Yes Matty I did check the CoG before flight as per plan, but I agree it looks a bit suspicious and may be marked incorrectly. Something else to look at. 

 

It seems like the CG conscensus on RCGroups is 50-55mm for this model; it sounds like that is not far from where the manual says it should be.

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