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Author Topic: Auto Launch, using the Sequencer  (Read 170 times)

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Offline Deerslayer

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Auto Launch, using the Sequencer
« on: March 13, 2019, 08:56:51 AM »
Here is a somewhat novel use which I am employing on some flying wings to enable an easy and worry-free hand launch. The actual programming details, while not terribly difficult, are not detailed; rather, if someone wishes to see what I have done and to try something for themselves, just ask.

Background

I have had my DX9 for 5 or more years now and gradually figured out most of its capabilities, why and how to employ them. All sorts of Mixes, Flight Modes, reassigning Channels, etc. One big mystery has been the Sequencer, a feature that is fairly common across several of the Spektrum products, such as the DX10 and DX9. Other Tx brands have similar capabilities, more or less complicated to implement. What I will describe is applicable there, too.

I have only ever seen Sequencing used or referred to in the application of, say, cycling landing gear doors and gear on scale planes (think Mustang) or on a scale sequencial startup of a 4-engine big bomber. Impressive, but I don't have either of those needs. But, I do have another problem which this may solve.

The Problem

I have owned, designed, built or bought many flying wings and deltas over several decades. They have one thing in common - they have to be hand launched (or via another of my techniques, from the arms of a lawnchair or a purpose-built launching rack - videos are posted elsewhere in the Forum). For hand launching, there are at least 3 common techniques, two of which I am comfortable with and use depending upon which plane is being launched. The common factor in hand launching is the need to coordinate Throttle and attitude of the plane prior to, during and at the end of the "fling", then to quickly get the launching hand onto the stick (in my case, it will be the Elevon stick) to follow through or sort out the tricky initial part of the flight - very quickly!

Some planes, such as the Optera or F-22 Evolution with AS3X, mostly look after things for you, provided you select its Launch mode. Here, the plane will be in self-levelling and I think that they may even hide some Elevon mixing with Throttle as well. This is nice, you hold the plane, advance the Throttle, fling it and watch it fly out and ascend slowly, allowing lots of time to get all hands on deck, release the self-levelling mode if desired and that's it!

Recently, I got a Sonicmodell HD flying wing which is a great flyer but has given me grief in launching. I have had several bad launches, minor repairs to the detachable nose and had developed a lot of apprehension regarding the plane. Then, I watched a video from a fellow in Indonesia where he had a wing that required a real hard toss - he used both hands and the Tx was sitting on the ground! He would do something via the Tx, set it down, fling the wing, watch it climb out, pick up the Tx and take over. Sweet! I think he had an iNav Flight Controller on board which has a Self Launch mode Could I make this happen with my DX9 and other stabilizers?

The Solution

Last year, I bought a couple of the BGAOLE  Flight Controllers, sold through Banggood. These are great little units which have 3 modes - Off, Balance (self-levelling) and Return To Home (RTH). As with my Guardian, AS3X, and Vector experience, the self-levelling was not of great interest, until now.

I now have what I call Auto Launch set up on my primary test wing, as well as the problematic one. Immediate success on the test wing, and immediate success later when I applied it to the Sonicmodell HD.

The DX9 supports 2 Sequencers, I think that the DX18 supports more and I am unsure how many are supported by other specific models in the product line. I only need one.

I set up a Sequence to operate the Throttle if my Launch Flight Mode is selected and depending upon the state of the "I" momentary button. I have always had a habit of giving the Throttle a quick jog, as part of my pre-launch preparation, just to ensue that things feel right, then applying Throttle during the fling. Very embarrassing to throw away an airplane, only to find that the motor is locked out or the battery is cooked.  :o My motor control has sometimes caused me problems, I think, as ideally one would carefully and consistently apply Throttle as the plane is accelerating from zero to its minimum control speed and beyond. I am a bit rough in that respect.

So, I am ready to fling with Launch Mlight Mode selected, Tx secured with my left hand and neck strap as usual. Press/Hold the "I" (Launch) button. The Sequencer activates and continues for the next (2 seconds or whatever I have set up) running through its pattern, unless I release the button. The Throttle quickly advances to perhaps 60%, then cuts off (think of a sawtooth with a ramp up and then a vertical drop). Then, there is a pause (I think of it as a 1,2 quick count) as I begin the toss. Sometime during my toss, the Throttle will again advance, smoothly, not as a jump to the firewall to whatever I have preset and then hold at that point until I release the Launch button. Have you ever hand launched something, seen things start to go wrong and been slow to cut the power before disaster struck? I have! At any time that the Launch button is released, the Sequencer chops the throttle to Zero and.and release control. Of course, you may have the Throttle stick partly advanced so that there is a smooth transition from Launch to Cruise setting.

OK, so the plane is in flight and you may be ready to take over. There is one more thing. The BG, or whatever flight Controller/Stabilizer is in use has its self-levelling mode, so use it. You could turn it on before Launch, then remember to turn it off if you suddenly feel the need to get more control during the first couple of seconds of flight. To make life easier, I set up a Mix which activates when the Launch button is pressed that invokes self-levelling as well as enabling the Sequencer. So, the launch pretty much looks after itself, controlling power and stabilizing flight despite turbulence, a bad toss, or slowness of the pilot to respond to some condition. Very relaxing!

On key thing that I learned was the technique of determining and setting the "level" reference to allow all of this to happen. It appears that for the BG, the ability of setting "level" is best use for calibrating, not for setting a very large base angle. Flying wings typically have a rather high angle of attack for slow flight, at least. So, to enable a climb, I wanted the BG to see "level" as an angle of incidence (the reference to ground) that is somewhat higher than the angle of attack required to fly and climb. I set the BG's "level" to its horixontal axis, then mounted it at approximately 15 degrees nose down on the plane. That way, it would try to keep the plane's angle of incidence at 15 degrees. I used a couple of the wedge-shaped pieces of balsa trailing edge stock (measures at about 8 degrees angle) glued together to achieve this. I had a couple of other wedges available, as the BG and the wedges are all Velcroed to the aircraft. It worked perfectly the first time - perhaps a new record for me!

I hope that this rather lengthy story may inspire someone else to look into more the the features of the incredible equipment that we have in our possession and new ways of using the features.

« Last Edit: March 13, 2019, 10:08:01 AM by Deerslayer »
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Offline ganguy

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Re: Auto Launch, using the Sequencer
« Reply #1 on: March 13, 2019, 02:14:52 PM »
Gary
this sounds very interesting as the problem you describe is one that I have all the time probably had 10 or 12 serious crashes because I'm trying to discus launch, and I'm just not fast enough to get back to the stick before the thing is in the ground.
However it sounds pretty complicated so the next time we get together you'll have to show me how to program it for my flying wing and then I can copy it for the others.
Reg
Churchill said: "Success is a series of failures during which one does not lose enthusiasm!"

Offline Deerslayer

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Re: Auto Launch, using the Sequencer
« Reply #2 on: March 13, 2019, 05:08:45 PM »
 I think you will find this well worth trying.

To do this, you need self-levelling capability in your system. The  Lemon  Stab+ has this, for example, and is the simplest/cheapest approach. Do you have one of these?

I haven't implemented the technique with that particular unit yet, although I happen to currently have one in a flying wing and one will likely inhabit a little sorta Su-27 that I need to get airborne.

I look forward to experimenting, along with you. Don't forget your glue gun! :)
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Offline Deerslayer

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Re: Auto Launch, using the Sequencer
« Reply #3 on: March 13, 2019, 06:12:24 PM »
I did some more flying today using the auto launching technique for the maiden flight of yet another homebrew flying wing. Even though I had the thing trimmed poorly and no real idea of where the CofG should be, all went well. The launch was effortless and absolutely perfect. The only problem was, as soon as I flipped out of self-leveling mode, I had a bit of a mess on my hands, requiring a lot of trim to control the plane.

I wrestled with it a bit and landed it fairly soon, went through a couple of iterations of tuning/flying and now have a most excellent Unidentified Foamy Object. I did not have any weights available at the field, or I would have corrected what I am sure is a marginal CofG. Perhaps I will do some experimenting soon, but meanwhile, the stabilizer and my auto launch system make flight possible and enjoyable.

I happen to have a Lemon Stab+, which has self-levelling, on another wing and I will soon experiment with that (no BG involved).

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Offline Deerslayer

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Re: Auto Launch, using the Sequencer
« Reply #4 on: March 14, 2019, 06:59:11 PM »
Today, I implemented the auto launch idea on another flying wing, my Micro Wing (details of that airplane were posted in here awhile back). Unlike the other couple of wings I have set up, this one did not have a Bigaole Flight Controller. It has the Lemon Stab+, which has self-levelling as one of its two stabilization modes, the other being straight gyro/stability stabilization.

This worked perfectly. Although launching has never been an issue for me with the Micro Wing, on a gusty day like today it can be a handful and you need to react quickly during the fling and initial 1 or 2 seconds of flight, as well as getting the best throttle setting. Under my auto launch mode, it is a piece of cake, despite wind conditions and even if you miss launching directly into the wind. Normally, you want to be very close to wind for launch, else you end up with a roll and possible dive at full throttle - very nasty!

Using the Sequencer to control the throttle and time its advance to ramp up nicely, along with having the Launch button set up self-levelling (which is really about 15 degrees up, for these wings), you get very consistent operation.

Today, I was playing with some settings of this, as well as trimming out the newest wing, so we had a couple dozen flights on each of the two wings. During the first take-off of the BG-equipped wing, there was a gust and major wind shift. Had I not been in self-levelling, the thing would have been severely tree'd! As it was, the self-levelling allows limited pilot control, just enough to dodge a couple of very nasty big evergreens south of the field.

I found the self-levelling mode on both the BG- and Lemon-equipped planes to be useful during pattern and landing, as there was severe turbulence down below treetop height. Again, you get just enough control to modify the "level" of the plane that you can do proper shallow turns, a good final approach and flare.

Either of these setups compare favourably with the AS3X system on the Optera or the F-27 for my purposes. One advantage, I find, is that all changes are made within the Tx, not in the Spektrum Rx (computer, application software, expensive little cable, access to the Rx, all required).

Reg, let's get going on setting up one of yours! If you wish, I can provide my SPM for one of my wings with auto launching, along with my documentation and you could perhaps try it out on one of your deltas that you have to hand launch. Perhaps this even fits within the spirit of the Flypaper Foamy Challenge, too. (After all, there are only 2 of us in that battle, as far as I can tell, and we just make up the so-called rules as we see fit, right?)

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Offline Deerslayer

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The "true" Auto Launch
« Reply #5 on: March 15, 2019, 07:35:11 AM »
Here is where I got inspired to do something to improve my wing launches.

https://youtu.be/dI6-oZjrCP0

This fellow in Indonesia has posted a number of really good videos and comments in rcgroups. The Flight Controller, an iNav, senses the initial acceleration of the toss, activates and handles the rest of it. The main difference between this and what I have been doing is this means of triggering the sequence. If I dared, I could lengthen the Sequencer to allow more time and move the activation over from the momentary I button to a switch - then, hope that everything goes smoothly until I can pick up the Tx and take over control. Perhaps this would be a neat test, when one of my wings gets near its end of life?

Note the flying site! Who has facilities like that? And no snow or ice! But, they do get monsoons, so I suppose there could be some negatives - no to mention, whatever kinds of snakes may slither around nearby. Python eat man; cobra bite man; man must watch his step; man learn to run, really, really fast!

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Offline ganguy

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Re: Auto Launch, using the Sequencer
« Reply #6 on: March 15, 2019, 02:07:56 PM »
very interesting, but I think the technology is getting the upper hand. maybe I'll get a round tuit this summer
Reg
Churchill said: "Success is a series of failures during which one does not lose enthusiasm!"

Offline Deerslayer

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Re: Auto Launch, using the Sequencer
« Reply #7 on: March 15, 2019, 06:45:45 PM »
Perhaps I made this sound to "techy". Sorry,  it really is quite simple.

I liked the way the Optera does this, recently got the new F-27 Evolution with the same and system really like it. The only issue, for me, was the "how", not the "why" and just required investigating what was already in my, and some others', hands. It was fun to figure out and the reward has been great.

I got tired and frustrated having to do nose jobs on a nice new wing that I flubbed too often, as well as having too much stress while developing and test flying a new design. Problem solved, in spades!

This has now been documented, only takes perhaps 15 minutes for me to set it up on something of mine, or yours, provided that it has gear as simple and solid as the Lemon Stab+ receiver/stabilizer ( < $40 ) and a suitable transmitter, such as DX9 (and probably even on one of them thar Graupners, Wilf!).
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Offline Deerslayer

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Auto Launch and wild winds
« Reply #8 on: March 17, 2019, 04:10:39 PM »
Today, out at the  Toyground, I got the long-awaited chance to really prove out the value of my Auto Launch system. Two of my flying wings, the Micro Wing and the 2nd generation of the Black Widow, were the test subjects. The winds really came up, with strong gusts, enough that I would normally not have flown either of these, or many of the other planes in my fleet. The launch would be just too difficult, plus I have better things to do than repair stuff right now. So, let's give 'er and see what happens.

With the big wing, it was hard enough to just hold it down by my side to commence the Launch. The little one was just twitchy to hang onto. But, both behaved exactly the same, and exactly as I expected.

Here goes!

Power up the plane.
Unlock the Throttle and initialize the ESC, leave the Throttle off but enabled.
Select the LAUNCH Flight Mode.
Press and hold the Launch button.
Elevons wiggle once ... 1 ... 2 ...
Start moving the plane, discus style and not very fast ... the motor ramps up as the fling is underway ... let go part way through the fling (the plane is still far from level) .. the plane accelerates away, leveling almost immediately, as the elevons become effective and it moves out in a gentle climb at full Throttle, steady as a rock!

Lots of time to get on the right stick and start hand flying it. Even in Self-levelling mode, you can still have limited control of Pitch and Roll. Vector, iNav and possibly some other Flight Controllers can command the Throttle, but the current Lemon Stab+, Guardian, Bigaole do not.

Whenever you are ready, release the Launch button and the Sequencer lets go of the Throttle and releases the stabilizer from Self-level Mode into whatever condition your Stabilizer Mode switch is set to on the transmitter - Off, Stability or Self-level.

On a day like today, Stability is a very useful mode, making it seem just like flying on a calm day - but, remember not to get terribly far downwind!

Self-level can even be useful during the pattern and landing phases, especially when you get down through the wind gradient and into the low level turbulence.

Man, this stuff really works! And it's not just for flying wings, or even for hand launching. Someone who may have mobility issues of some sort may be able to put this to use. (Who knows, you I may even be there someday yet would still like to enjoy some low stress flying).

Again, if someone would like to learn more, or see a demo, or try setting this up on one of their own flying objects, I would be happy to try to help you.
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Offline Deerslayer

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Auto Launch Video
« Reply #9 on: March 23, 2019, 07:10:37 AM »
Continuing on with my ramble ... Roger "Steady Cam" Harrison and I had big fun flying and recording earlier this week. That boy does a fairly good job; I may even have to give him a 10% raise, someday.

The narration in this video leaves a lot to be desired :(  What the dude refers to as a "javelin" launch method explains a lot about why he never did Track and Field back in the old days. Clarification:The javelin is that long pointy thing that can be used to, I guess, spear groundhogs and slow-moving squirrels. The technique for flinging a flying wing is properly referred to as a "discus" launch, that is the one like where the T&F folks toss a big, heavy frlsbee-looking plate at the snakes, or whatever. Best to avoid all of that and just fly toy planes, methinks. Incidentally, the plane in this video really, really did not like such a throw (Sorry, Roger, your camera work was perfect, but I sort of omitted that little "failed launch" segment in the final product, as I suffer enough embarrassments without going out of my way to document them.)

https://www.youtube.com/watch?v=IrqHkADgDaM&feature=youtu.be
« Last Edit: March 23, 2019, 07:13:24 AM by Deerslayer »
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