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Aug 07, 2018, 12:59 AM
DLG Fan
Discussion

DLG Launch Mode - Before or After Release?


Do you folks engage Launch Mode before or after releasing your DLG?

Per several pro's suggestion, I have been engaging launch mode before starting my rotation and switching to zoom mode an instant after release. It seems to me, though, that up elevator during rotation may be placing a lot of strain on the fuselage.

Your thoughts?
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Aug 07, 2018, 02:13 AM
Registered User
Ifly_65's Avatar
Im newer to DLG so a pro can chime in here, but I would think that attempting to activate the launch preset after it leaves your hand would be very tough to do. It may be riskier than the actual strain on the bird by holding the preset. It doesn't take much up elevator in launch mode, so I cant imagine that it would cause any damage. Although I now have @200 flights, one of my very first tosses I forgot to hold the launch button. I sent it off straight with the horizon. I was able to adjust but it wasn't fun.
Aug 07, 2018, 06:02 AM
Registered User
Usually all the time in the launch spin.

If you "I sent it off straight with the horizon" that's not a bad thing. You are launching flat which is the better way to get speed (therefore height) than trying to throw up.
Aug 07, 2018, 10:57 AM
Registered User
Definitely up elevator on launch and release the switch once it is vertical. Zoom mode might be needed for certain models like the Vibe where a little bit of up camber is recommended for launch, but if flush is only needed for launch, then you can do what I do and go from launch to speed mode.

Don’t worry about the stress on the tail during launch. The best description I’ve heard is that a carbon DLG will never break when it’s doing what it is designed to do, but is fragile when force is applied where it’s not supposed to be (accidentally stepped on, a tailgate closed on it, other horror stories like that)

Of course, if it’s a Hobby King DLG, then that’s a different story. It might just explode into flames for no reason. =)
Aug 07, 2018, 11:02 AM
solastagia
kcaldwel's Avatar
There was a whole thread on this topic not too long ago. Bottom line, Joe Wurtz applies the pre-set after release, although many do it all through the launch rotation. Theoretically, there should be a bit less drag, and therefore a higher speed and launch, if the pre-set is applied after release.

https://www.rcgroups.com/forums/show...Dangerous-Game

Kevin
Aug 07, 2018, 11:15 AM
plays with toy planes
Let me add that it's possible for normal humans to miss the launch switch entirely. At least once. Joe Wurts has many legendary super powers. Me? None. I mash that button down before I take a step.
Last edited by barry d; Aug 07, 2018 at 11:32 AM.
Aug 07, 2018, 12:55 PM
Registered User
Ifly_65's Avatar
Quote:
Originally Posted by DougMaxwell
Definitely up elevator on launch and release the switch once it is vertical. Zoom mode might be needed for certain models like the Vibe where a little bit of up camber is recommended for launch, but if flush is only needed for launch, then you can do what I do and go from launch to speed mode.

Donít worry about the stress on the tail during launch. The best description Iíve heard is that a carbon DLG will never break when itís doing what it is designed to do, but is fragile when force is applied where itís not supposed to be (accidentally stepped on, a tailgate closed on it, other horror stories like that)

Of course, if itís a Hobby King DLG, then thatís a different story. It might just explode into flames for no reason. =)

Hmmm, the instructions for my Vibe 2 say to add 2-3mm of down flaperon for launch, not up...?
Aug 07, 2018, 01:25 PM
Registered User
Quote:
Originally Posted by Ifly_65
Hmmm, the instructions for my Vibe 2 say to add 2-3mm of down flaperon for launch, not up...?
Yes that’s common-2-3 mm down flap while pressing /holding the launch switch- then it goes into reflex - zoom mode with ailerons up 1 -2 mm as soon as you release the switch. ( slightly after launch)

I hold my switch as I start my rotation -and during launch - then I release it as soon as the ship turns up to vertical- at this point it’s in zoom - when I reach the top and pushover with elevator the mode automatically switches to speed/ cruise / or thermal mode with flaps positioned depending on what mode the flight mode switch has selected.

( I fly Taranis with Jaspers excellent JFf3k program on my Taranis QX7).


The down flap at launch helps the rotation into vertical for the climb in launch. The reflex cleans up the wing for less drag during the climb out .

Jack

At least this is how I do it - I”m sure there are others doing it differently - but this works for me.
Aug 07, 2018, 01:36 PM
a.k.a. Bob Parks
If you are old enuf to remember control line stunt planes, the flaps are used to help rotate the front of the plane up, as the tail is going down, as when
trying an inside loop.

BP
Aug 07, 2018, 01:51 PM
solastagia
kcaldwel's Avatar
The real reason for downward flap deflection during the rotation is to reduce the drag during the pull-up. The wing is operating at a Cl of +0.3 or so during the pull-up (depends on the radius), and the wing will have less drag at that Cl with a small downward (+) flap deflection. That will reduce the energy lost during the pull-up.

The downward flap deflection does also increase the angle of attack of the wing, which will make the pull-up faster, but the decresed wing drag at the higher Cl is the primary reason to use it. You don't want to pull-up too quickly, or you risk losing too much energy.

Kevin
Aug 07, 2018, 04:13 PM
G_T
G_T
Registered User
A Cl of 0.3 would be in the speed setting range.

Gerald
Aug 09, 2018, 03:19 AM
Aussie F3K Team
Hi all,
I'd recommend getting an altimeter and creating your own results. They might surprise you. The practical side has more variables than the theory.

The iterations for the DOE (Design of Experiments) are:
1. rotate mode with flaps set at +2mm , +1mm, 0mm, -1mm flap.
2. Button on all the way around the spin or after the spin.
3. Sharp rotation (lots of up) or moderate rotation (not much up).
4. Zoom mode with +1mm, 0mm, -1mm, -2mm

I'll guarantee every pilot/plane has a different optimum, but you can find your own within 3 or 4 sessions. Take a pen and paper, do three throws on each, make a change, repeart. Once all the iterations are complete, do it a second time as the conditions can upset the results (you will be surprised). I personally run it a 3rd time.

Results for me:
My optimum with the Snipe, Vibe and NXT are all similar.
1. 0mm for rotate mode
2. Button on before spin (also good for repeatability and safety).
3. moderate rotate radius.
4. Each plane had a different zoom mode flap setting. The optimum also varies depending on angle (vertical or 60 degrees) you like to launch, I like 60 degrees these days as I can see the plane better and it gives me a tactical advantage at the expense of 2-3m.

YMMV.

Marcus

I might post this in the other thread as well.
Last edited by Machineman; Aug 09, 2018 at 03:25 AM.
Aug 09, 2018, 06:03 AM
Hugh Blackburn
floquet's Avatar
I hit the preset as I'm about to let go...
Aug 09, 2018, 10:08 AM
Registered User
Quote:
Originally Posted by Machineman
Hi all,
I'd recommend getting an altimeter and creating your own results. They might surprise you. The practical side has more variables than the theory.

The iterations for the DOE (Design of Experiments) are:
1. rotate mode with flaps set at +2mm , +1mm, 0mm, -1mm flap.
2. Button on all the way around the spin or after the spin.
3. Sharp rotation (lots of up) or moderate rotation (not much up).
4. Zoom mode with +1mm, 0mm, -1mm, -2mm

I'll guarantee every pilot/plane has a different optimum, but you can find your own within 3 or 4 sessions. Take a pen and paper, do three throws on each, make a change, repeart. Once all the iterations are complete, do it a second time as the conditions can upset the results (you will be surprised). I personally run it a 3rd time.

Results for me:
My optimum with the Snipe, Vibe and NXT are all similar.
1. 0mm for rotate mode
2. Button on before spin (also good for repeatability and safety).
3. moderate rotate radius.
4. Each plane had a different zoom mode flap setting. The optimum also varies depending on angle (vertical or 60 degrees) you like to launch, I like 60 degrees these days as I can see the plane better and it gives me a tactical advantage at the expense of 2-3m.

YMMV.

Marcus

I might post this in the other thread as well.

Excellent advice . I always practice with the altimeter (frysky grx6= awesome) . And I have logged my launch heights like you said and adjusted my set up to yeild a good launch height .
I noticed you can actually hear the difference on my BAMF when I got it set corrrctly .
Jack
Aug 09, 2018, 10:44 AM
plays with toy planes
Great post Machineman. Same routine here, but I skip variable 2 because I can miss pushing a button, but I'm pretty good at releasing them (and it is an actual tactile button, plus an alarm and haptic).

Jack's right about the BAMF, which IME really responds to small reflex adjustments in rotate and zoom. Then you hear that BAMF sound.


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