Control throws on Indian V glider

[ahdofu]

Hi Konrad,
I suspect it will be you who gets to respond to this question. I am setting up the throws for the flaps on my Indian V glider and I have some questions related to the attached pic.

1. For landing the manual shows a 30 mm traverse which translates to a ~50 deg flap deflection. Have you ever found it necessary to go beyond 50 deg on a glider? On two glow planes that I've had in the past, flaps became really effective at 90 deg - much less so at reduced deflection angles. However gliders may be more sensitive to flap settings hence the question.

2. The picture appears to suggest that the flap can deflect upward by 2 mm. What is this for?

3. For Thermik (thermals?) the pic is suggesting a downward deflection of 2-3 mm for flaps and a similar amount for the both ailerons. Do you have a special proportionality function on your radio for thermals?

 

[Wayne]

Typically flaps will work best as a flap at 40 to 50 degrees for most all aircraft, angles beyond this will start to act more as an air brake. The ideal angle for function as a flap needs to be tested to discover the right angle for the best performance.

For example, I am building a full scale plane called the Glastar. One builder did a lot of testing and found he could actually land shorter by reducing the angle of his full flap setting by about 3 degrees.

Speed brakes - are a different critter, they are really just a ton of drag to slow the plane down.

Yes, the 2mm up is a reflex setting for a speed mode. You might use a speed mode when flying from one thermal to the next to avoid being in sink too long. Or just to go a little faster to impress your friends.

The 2-3mm of down is generally called camber and increases the lift on the wing slightly and also slows the plane down some to stay in the thermal longer.

So we have 3 basic flight modes on a glider. Normal, Speed and Thermal. You may also have a 4th mode for a landing configuration, and a 5th mode for aerobatics. I will suggest playing around some as not all gliders will work well with camber or reflex. And each design will like something a bit different.

 

[Wayne]

It looks like they are showing a high and a low rate for the ailerons high is 15-18 and the low is 8-10

 

[Flying Dutchman]

The 15-18mm (Up) and 8-10mm (Dwn) look like aileron differential, not rates. You want less downward travel than up on your ailerons. Reason is that (for the same amount of deflection) you generate more drag with them down than you do up, which causes the wing with the aileron down to make the plane yaw in that direction (aka 'adverse yaw'). That is generally the opposite of what you want in a turn. Hence the 'Differential' setting on most computer radios. But as Wayne said, the amounts are very model-specific.

 

[ahdofu]

Yes it is a differential aileron setup for the reasons that FlyingDutchman has noted. Going back to my original question I am still not quite there in setting things up on a radio. I understand that on a glider the traditional throttle stick on the radio controls the flaps. And once the crow functionality is brought in, ailerons will move up as flaps are deployed and of course some elevator will have to be mixed in to. So the left stick helps the pilot control the amount of "drag" in this configuration. Now how do you enable a thermal feature? In your radios do you toggle a switch and now the left stick becomes a controler for the thermal feature or ...?

 

[Flying Dutchman]

My full-house glider is motorized, so I use the Throttle stick for power (out of habit). The flaps are on a 3-position switch (Up/Mid/Crow), i.e. I don't modulate Crow - it's either full On or Off. Works fine for me, but the real pros may scoff at that; I generally only use Crow for landing.
Of course you could put Throttle on an On/Off switch instead, because it's really only used at 100% - to launch or get back up.
For Thermal and Reflex I use a dial (my QX7 has no sliders) which controls the whole trailing edge (Ailerons & Flaps mixed). I used to do that with a 3-pos switch, but I like the idea of tweaking it with a dial - probably overkill though.

 

[Konrad]

I see two basic questions here.
1.How are the controls set up for a glider.
2.How does one program the radio to get this functionality.

To question one I like to have as many of the flight controls set up on a variable control. I like to be able to adjust the camber, aileron differential, flaps (camber, thermal mode), snap flap, and crow elevator comp, all in flight.

I find that I NEED to have crow on one of the main sticks! It is the most important control second to the elevator while landing. In my glider flying the throttle is little more than an on off control. So switching power with a 3 position switch is ok if one runs out of variable control (pots, slider, control stick, etc).

The second question is a radio programing one, in how does OpenTX mix and assign these functions?
This can get deep into the weeds. So look for mixing tutorials on the web.

To help with both questions I like to point fliers to Soaring-RC.com. Take a good look at Mike Shellim's templets. Note how he distributes the aircraft functions to the radio controls.

E-Soar Plus template for F5J / F5K

E-Soar Plus template for F5J and F5K sailplanes and OpenTX or EdgeTX

rc-soar.com

Also take a look at his Excel spread sheet for ideas as to how to incorporate his mixes into your programing.

Note: There is a lot of power in those templets that can quickly overwhelm anybody, new or old to OpenTX. I'm not recommending you use the templets (I don't think the Indian V has enough versatility to warrant their use). With that being said I love the CAL mode for setting up dual servo controls if your set up uses these. (Most performance gliders will use 2 servos for the ailerons, 2 servos for the flaps, and if a V-tail 2 servos to combine elevator and rudder functions). I would now hate to set up a glider without the use of one of Mike Shellim's templets

All the best,
Konrad

P.S.
Gliders offer the most opportunities to use the full mixing (programing) power from the radio. It is up to you to determine how sophisticated you want to be. Note, you can start out with a simple program and add functionality as your flying and programing skills develop.

 

[Wayne]

The 15-18mm (Up) and 8-10mm (Dwn) look like aileron differential, not rates.

Ahh, I see, I read it slightly differently, but think you are right. I thought it was showing a high rate with differential and a low rate with differential, but I think you are right, they are just showing a range with the differential. LOL

 

[ahdofu]

Konrad,

I have placed the flaps on the throttle stick. Although the manual suggests a 50 degree flap angle, right now they go as high as 90 deg. Eventually when I do fly this glider, I'll fine tune the max flap position. I think with my limited JR X388S radio the only way that I may be able to do a thermal is to assign that functionality to either a toggle or a rotary switch.

For throttle I have two options. Either have it on a toggle or a rotary switch. I suppose I can do both. Have the toggle switch control two settings for the throttle and have the rotary be able to fine tune the throttle. As time goes on I should be able to add the thermal functionality to either a toggle or a rotary switch.

Assuming that in the past you've used 72 mhz radios, what has been your experience in the Rx antenna placement? I can place mine inside the tail boom and it will run all the way to the end of the tail boom. I suppose the other alternative is to tape it to the side/outside of the tail boom.

 

[Konrad]

Yikes, that's going way back deep into my gray matter. (So you aren't using OpenTX)?

I had a Jr XP8103 and found it very limiting when trying to program E-powered sailplanes. (I loved how it fit in my hands, but hated the programing power).
Sorry this site won't allow me to post a PDF (If you can't find the document I might be able to send it to you. Contact me through this site's "Inbox" with your email.

I think there is a well documented work around for the JR limitation by a guy going by the name Miami Mike. Do a search for; Programing the JR XP8103 Radio For an Electric-Powered, Six-Servo Sailplane.

As the boom has little carbon running the antenna inside the boom should be fine.

Toggle the throttle. If the ESC has any ramp up adjustments try to set them for about 1.5 second to reach full power.
The Indian V is such a light glider it won't need the 90° flap. 50° might use the fuselage depth for flap protection should you fail to bring up the flaps fast enough on landing. (The last meter or so of height is done with the flap up to protect them from the rocks and weeds.

If you can't do reflex don't worry about it. The Indian V still has a lot to teach you.

You once asked what would be a good next sailplane purchase. I think it might be a more powerful radio.

 

[ahdofu]

Thanks Konrad. I sent you my email address separately.
Did not know about the ESC's ramping capability. Need to look into that.
I have a new JR XG11 radio that is still in the box. I decided to use what I am accustomed to (aka old reliable X388S) first on a new model before switching radios eventually.