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Flyswamper
28th September 2014, 08:08 PM
Hi folks,

Relative newbie here. Have my Z3 put together and have made a few flights with her. The first flights were done before I put any fpv gear on the plane. I was able to successfully hand launch it for each flight with the following setup and conditions:

2x 3S batteries (4200+5100mah), Castle 75A ESC, Eflite Power25 1250kv, 10x5e prop
In all my successful early flights (perhaps 5 or 6) I generally had noticeable amount of wind.
(maiden flight video showing a successful hand launch (http://youtu.be/JaB8FMFhtjo))

Fast forward to this weekend.... the antenna that I had been waiting on arrived and I added fpv gear to the Z3. Things added include:

400mw 1.3Vtx
1.3 Skew Planar antenna
Ritewing Mobius toughbox
flight camera
808#16 camera
associated cables
and a couple of air scoops made out of 1/2 of a plastic spoon for airflow.


So...having added the gear a flying buddy came over and I decided it was time to try to make a short range fpv flight with her. Trouble is I never got her into the air. I'm still inexperienced enough not to be certain of what the troubles really were. But... it seemed to me that she would just roll over and nose into the ground no matter what I did. I'm guessing I just wasn't getting enough speed and airflow over the control surfaces to have any control and get her into the air. At the field I just assumed it was the extra weight that made the difference. However, in hindsight I realize I had several factors I think might have been working to make it harder this time. Those include...



extra weight of the fpv gear
was a calm day, lack of headwind that I had on prior successful attempts
Also, I put in a single 3S 8000mah battery this time.


With regard to the last point... am I right in assuming that I might have gotten slightly less rpm/thrust by putting a single 3S battery in the plane? What I'm guessing/thinking is that the single battery might drop voltage a bit lower when opened up to full throttle than the pair of batteries did. I have no clue if this could be significant or not...just an idea....wondering what you guys might suggest? Also... would I be correct in assuming that it would be noticeably easier to hand launch into a decent headwind than it would be on a calm day?

As a result of the failed launches I needed to inject a bit of CA glue into key spots on the nose to get some of the strength back (I nosed her in multiple times trying). Nothing awful happened, just a little battle weary now on the nose section. But, this had me looking carefully at ecalc for my battery/prop options. From what I can see, with my 3S setup and my 10x5 prop ecalc suggests I'd have ~68oz of thrust. By simple switching to a 4S setup with the same prop it suggest that I'd goto 111oz of static thrust and the max current would still be below (slightly) my ESC's continuous current rating.

So.... I ran out and grabbed the only 4S battery my local hobby store had... a 4000S Eflite battery. Haven't tried to fly with it yet, but hopefully it will make a big difference and I can get back to hand launching. Having said that, this little episode has me looking at bungee launcher options for the first time. I *REALLY* don't want to be carrying around any more kit than I need to though. Not sure where I'll go with it. Perhaps a bungee launcher that is basically just a stake and a bungee cord without a launch-rail-frame setup? I've seen a video where someone seemed to use this type of setup (might have been AtariJoe?). Looked like it worked for him... not sure how it would go for this newbie though...

anyway... thanks for listening... and most importantly thanks for any words of wisdom you guys can share that might help.

Manzooka
28th September 2014, 09:21 PM
A headwind can make a very significant difference. Ever seen that "how to launch a ZII" vid by rockyFlyer? On his first launch he tosses his ZII unpowered like a baseball into a huge headwind and it climbs about 20 feet before he powers it. Having that unrealistic expectation made my first launch attempts rather comical to observe. Here's a link to the vid if you haven't seen it. www.youtube.com/watch?v=1U2LaAnzQQU

The next thing that comes to mind is CoG. I'm sure you did your due diligence but in the interest of covering all the bases did you check your CoG after installing your FPV gear, and about where is your CoG now?

Of course as your calculations showed going from 3S to 4S should also make launches easier. Another thing that helps (and I know this sounds super obvious too) is to really put some force into your toss.

Nothing wrong with a bungee or a catapult, but when you mentioned tying a bungee to a stake it conjured up a frightening visual. Be sure to secure that stake! ;)

IBCrazy
28th September 2014, 10:39 PM
It all comes down to having enough static thrust. If you have 80% or more of your plane's weight in thrust, you should be able to get it airborne without too many problems.

Also, rather than a bungee, try a trebuchet. This pulls the plane more gently and gives it plenty of altitude on release.

-Alex

ritewing
28th September 2014, 10:41 PM
3s is too little V for that low of KV, 4s is what you need, 3s is nominal at best if not loaded full of fpv gear, if you going 3s you will need around 1450 kv

Deadstick
28th September 2014, 10:51 PM
Factors:
Wing loading
arm strength
headwind
power available
technique

gobigdale
28th September 2014, 10:53 PM
4S, 4S, and only 4S on the Z3. Had a great flight today on 1250kv on 4s with 10x5e. Jumped out of my hand and into the air.

On 3s this thing dove to the ground and bent up the nose...

Flyswamper
29th September 2014, 08:30 AM
Thanks fellas... I've got a 4S battery for it now, but I think I'll wait for a bit of headwind (which shouldn't take too long!) before I give her another toss. In hindsight, I guess I didn't realize just how much assist I was probably getting from the wind at launch time. Thanks for the suggestions and feedback.... It all helps!

I had initially planned to go 4S with this plane, I just hadn't bought a 4S battery yet. So... I went out and gave it a try with 3S. The relatively easy/successful launches I had with just 3S I guess gave me a false impression about how easy it would be to keep doing it that way with my current motor/prop. (which I bought planning on 4S...).

ritewing
29th September 2014, 12:11 PM
Show me your trebuchet I will show you mine!
It all comes down to having enough static thrust. If you have 80% or more of your plane's weight in thrust, you should be able to get it airborne without too many problems.

Also, rather than a bungee, try a trebuchet. This pulls the plane more gently and gives it plenty of altitude on release.

-Alex

Flyswamper
29th September 2014, 07:36 PM
The most intriguing bungee thing I've seen so far is this.....

http://www.mygeekshow.com/watchmygeekshow/episodes/Episode_145_Epic_RC_Crossbow_Launcher.html

Curious what others say


oh...and the one with the smallest trebuchet wins.

represent
29th September 2014, 08:52 PM
Also, rather than a bungee, try a trebuchet. This pulls the plane more gently and gives it plenty of altitude on release.

-Alex

Sorry Alex, but LOL at this advice. A trebuchet, really??? No way someone is going to build one of those easily, much less launch a wing from it

Manzooka
29th September 2014, 10:04 PM
Sorry Alex, but LOL at this advice. A trebuchet, really??? No way someone is going to build one of those easily, much less launch a wing from it

I believe this is what Alex is referring to, and they're not very hard to build. One of my flying buddies made one.


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

Flyswamper
30th September 2014, 11:15 AM
Thanks... that does look very portable and relatively easy to build.

represent
30th September 2014, 05:47 PM
That looks like a catapult, not a trebuchet. Interested to see what exactly Alex is talking about

Manzooka
30th September 2014, 08:51 PM
That looks like a catapult, not a trebuchet. Interested to see what exactly Alex is talking about

I'm pretty sure that is what he's referring to as that and the bungee seem to be the most common launch assists. That being said, I would love to see someone build a real trebuchet and unit it to launch a wing, lol. That would be awesome.

zaraja
1st October 2014, 10:04 AM
Hi,

I understand that the 4S will help, but just try 11X6 prop and see the difference. I can bet it will hand launch very easily even on 3 cell ....


Hi folks,

Relative newbie here. Have my Z3 put together and have made a few flights with her. The first flights were done before I put any fpv gear on the plane. I was able to successfully hand launch it for each flight with the following setup and conditions:

2x 3S batteries (4200+5100mah), Castle 75A ESC, Eflite Power25 1250kv, 10x5e prop
In all my successful early flights (perhaps 5 or 6) I generally had noticeable amount of wind.
(maiden flight video showing a successful hand launch (http://youtu.be/JaB8FMFhtjo))

Fast forward to this weekend.... the antenna that I had been waiting on arrived and I added fpv gear to the Z3. Things added include:


400mw 1.3Vtx
1.3 Skew Planar antenna
Ritewing Mobius toughbox
flight camera
808#16 camera
associated cables
and a couple of air scoops made out of 1/2 of a plastic spoon for airflow.



So...having added the gear a flying buddy came over and I decided it was time to try to make a short range fpv flight with her. Trouble is I never got her into the air. I'm still inexperienced enough not to be certain of what the troubles really were. But... it seemed to me that she would just roll over and nose into the ground no matter what I did. I'm guessing I just wasn't getting enough speed and airflow over the control surfaces to have any control and get her into the air. At the field I just assumed it was the extra weight that made the difference. However, in hindsight I realize I had several factors I think might have been working to make it harder this time. Those include...




extra weight of the fpv gear
was a calm day, lack of headwind that I had on prior successful attempts
Also, I put in a single 3S 8000mah battery this time.



With regard to the last point... am I right in assuming that I might have gotten slightly less rpm/thrust by putting a single 3S battery in the plane? What I'm guessing/thinking is that the single battery might drop voltage a bit lower when opened up to full throttle than the pair of batteries did. I have no clue if this could be significant or not...just an idea....wondering what you guys might suggest? Also... would I be correct in assuming that it would be noticeably easier to hand launch into a decent headwind than it would be on a calm day?

As a result of the failed launches I needed to inject a bit of CA glue into key spots on the nose to get some of the strength back (I nosed her in multiple times trying). Nothing awful happened, just a little battle weary now on the nose section. But, this had me looking carefully at ecalc for my battery/prop options. From what I can see, with my 3S setup and my 10x5 prop ecalc suggests I'd have ~68oz of thrust. By simple switching to a 4S setup with the same prop it suggest that I'd goto 111oz of static thrust and the max current would still be below (slightly) my ESC's continuous current rating.

So.... I ran out and grabbed the only 4S battery my local hobby store had... a 4000S Eflite battery. Haven't tried to fly with it yet, but hopefully it will make a big difference and I can get back to hand launching. Having said that, this little episode has me looking at bungee launcher options for the first time. I *REALLY* don't want to be carrying around any more kit than I need to though. Not sure where I'll go with it. Perhaps a bungee launcher that is basically just a stake and a bungee cord without a launch-rail-frame setup? I've seen a video where someone seemed to use this type of setup (might have been AtariJoe?). Looked like it worked for him... not sure how it would go for this newbie though...

anyway... thanks for listening... and most importantly thanks for any words of wisdom you guys can share that might help.

represent
1st October 2014, 08:10 PM
I'm pretty sure that is what he's referring to as that and the bungee seem to be the most common launch assists. That being said, I would love to see someone build a real trebuchet and unit it to launch a wing, lol. That would be awesome.


LOL that's what I had in my mind when I read Alex's post... https://www.youtube.com/watch?v=iO-DUbCe0cY#t=61

Manzooka
1st October 2014, 08:41 PM
LOL that's what I had in my mind when I read Alex's post... https://www.youtube.com/watch?v=iO-DUbCe0cY#t=61

Well to be fair it would probably be very effective, lol. But will it fit in a backpack ground station?

Flyswamper
1st October 2014, 09:00 PM
This is what I found when I did the first search after reading Alex's note... Entertaining for sure.... just not very portable I think. :)



https://www.youtube.com/watch?v=c-n5HrKivvo

Flyswamper
3rd October 2014, 05:10 PM
Good news and bad news.... The 4s setup has plenty of power to make hand launch a piece of cake. :) The bad news is I need a new elevon and another one of those pieces of plastic pieces that glues to the wing for the wing joiner. Had an encounter with a power line already. :(

vtexpress
5th October 2014, 02:44 AM
Well to be fair it would probably be very effective, lol. But will it fit in a backpack ground station?

Challenge accepted!

vtexpress
5th October 2014, 02:45 AM
Well to be fair it would probably be very effective, lol. But will it fit in a backpack ground station?

Challenge accepted!

fireflyer451
5th October 2014, 09:41 AM
Flyswamper, what is your all up weight with batteries of choice? Why not try starting with a simple bungee. Very portable and it has really helped me sort out the CG and elevon throws without wrecking things too much. And for all this initial testing it is less stressful and more consistent than a hand launch. Here is a short video of my Z3 launch yesterday with just that, AUW 2640 grams, using 4S, Ritewing 1200kv motor, 10x6 Eprop.

http://youtu.be/NIxaRnYnquI

I have the elevons cut a bit short so there is a small space between the inside of the elevon and that large vertical fin. This way I can hold the wing, and walk back to tension the bungee. Transmitter hanging around my neck. Walk the bird back, hold at about chest high, then release. As you can see it sails away and I have plenty of time to get hands on the transmitter and start flying. I'm still sorting out things once I get under power and fly around. But it is a stepwise process with a new bird.

Good luck

Manzooka
5th October 2014, 07:14 PM
Fireflyer451, just have to say that that is such a cool "whoosh" sound when you release the bungee. Love it.

Manzooka
5th October 2014, 07:17 PM
Challenge accepted!

So wait a minute, you posted this at 2:45 am and still managed to get to the field today at 7:00?! Well done, sir. Well done.

But to keep this on topic... my new favorite Zephyr launch method is to have vtexpress do it.:cool:

daggad
7th October 2014, 03:46 PM
Vector on 2D mode. Trim up quite a bit or make a switch that add about 20% elevator. 3/4 power and toss. Pick up your radio when you are ready to fly it yourself.. ;)

Flyswamper
7th October 2014, 06:34 PM
Hmmmmm. I've got the vector in mine now.... bench testing done.... hopefully I can launch as you suggest. But I think the first one is gonna be with vector turned off. Just need to verify gains are reasonable and vector is working/configured like I *think* it is for that first flight.

Hoping to get it in the air tonight but may have to wait a few days.

fireflyer451
7th October 2014, 06:50 PM
Daggad & Flyswamper,

I have been using Vector 'Gyro' mode to do the launches in the video above. And I have a Mini-Talon that I use the same mode to launch with. I think that Gyro is close to or the same as Guardian 3D mode. It has been great for launching and flying in windy conditions, yesterday was blowing 12-18 on the ground during launch. All went smoothly.

Flyswamper - going with manual mode is smart, if you have a bungee to test glide it with all the better.

Anyway, here is the launch process used in that video.

1. Plane is flat on the ground with the bungee hook clipped into the bottom.
2. Lift the plane's nose up about 15 or 20 degrees, then engage 'Gyro' Mode on your mode switch.
3. Do not touch the AIL/ELE stick at all after doing this. Pick the plane up and prep for bungee release.
4. Pull back and launch, when the hook falls free from the plane engage throttle. Climb to some comfortable altitude in Gyro mode
5. Switch to 2DH mode and make sure all is flying happy.

It flies quite stable when it comes off the bungee in Gyro mode, although I've not just punched the throttle and let it fly very far on its own in Gyro mode. But now I am going to add that to the list.

Daggad, if you have a video of doing that 2DH launch please post it, I'm sure folks would like to see it.

Flyswamper
7th October 2014, 07:37 PM
Thanks for the suggestions and tips. I have a feeling that I'm eventually going to get comfortable and even addicted to using a bungee launcher. At the moment though, it is something I've never even attempted. Sure does look like a pretty good way to go about launching though and, as you said, doesn't really require a lot of extra baggage/gear or setup at the flying field. I guess if I am going to try it I'll have to figure out how to attach a hook to the plane in a way that is secure enough for launching.


What do you guys do for a hook? Would something like this work with a bit of CA glue added and maybe some lam/tape over the edges of it? I'm thinking I could take a razor and dig a little indentation into the foam landing skid so that the hook pushes up against a little ledge of (glue/lam reinforced) foam as well. Not sure about placement, materials, or anything for that matter. :)

vtexpress
7th October 2014, 08:57 PM
So wait a minute, you posted this at 2:45 am and still managed to get to the field today at 7:00?! Well done, sir. Well done.

But to keep this on topic... my new favorite Zephyr launch method is to have vtexpress do it.:cool:

Every time I go flying I get so excited I can't sleep, I'm like a 5 year old haha... The Z wasn't nearly as bad to launch as I had feared. I'm so happy I didn't throw your bird into the ground, and of course it helps if Manzooka is controlling said launch lol. So there you have it, the best way to launch, get a humanoid robot.

fireflyer451
7th October 2014, 10:52 PM
Flyswamper,

New to the Bungee, me too. I had only used one a time or two. Because real men throw plane into the air like a friggin Caber Toss! Yes, well after building, then nose smacking my Z3 due to CG issues I went back to the bungee. Found a big grassy field, took the prop off and played for about 20 launches. Dialing in the CG all in a low stress environment. For me the result is clear.

Here are some photos about adding a hook. I used a 50lb metal wall hanger hook with two screw slots. This hook holes are angled so that when you put stress on it, in the direction of pull, it locks onto the bottom of the plane. Used 3mm bolts and nylocks. I mounted it just behind that hump on the bottom of the Z3. It is low profile and will not touch the ground normally.

Hook is gooped to the bottom of the plane. I cut the 3mm bolts off inside the front box as short as I could, yet still get the nuts on. There is a piece of plywood inside the box that the bolts go through and the nuts/washers lock against. Then gooped a piece of plywood over those nuts the keep batteries from being goughed. You can see the velcro on top of that small plywood cover. My plane also has 1.0 oz kevlar cloth glued to the bottom, center section. So that adds a ton of strength. But if you mount that hook with small piece of plywood between the hook and the foam it should be strong enough. Others can chime in how they attach their hook.

Don't let the time/effort you think it might take to mount a hook deter you. You'll be glad you did it. The hook is very strong

daggad
8th October 2014, 03:13 AM
Will try to have someone film my launch the next time I fly. But I throw it myself, no bungee if that is what you tought.
And I use the Vector 2D mode. Not hold as that would stop it from climbing I guess. :)

billyd
8th October 2014, 04:43 PM
I believe this is what Alex is referring to, and they're not very hard to build. One of my flying buddies made one.


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



No that's not a trebuchet. That's a bungee launcher. Nice design too!

daggad
8th October 2014, 06:16 PM
Posted this initially in the wrong thread, should be here.
I find it very easy to launch. But also fly it only with 1 x 5000mah 4S.


https://www.youtube.com/watch?v=yTd1iRFS92U&feature=youtu.be

Flyswamper
8th October 2014, 10:47 PM
Thanks again guys... well... I haven't managed to fly the last few days...wife's birthday was today...so no flying today;) But I did manage to stop by the hardware store and pickup a hook similar to what firefly showed. Got it installed in the plane and I think it's gonna be very secure.... very similar to what firefly did but I have wood on both the bottom/outside and the inside of the plane. Only used one screw through the center of the triangle which is also covered by a glued-down strip of Velcro that runs through slots in the wood on both sides. Also used the nail/spears which penetrated the exterior wood but not the interior... also ran and glued a Velcro wrap around/through the wood and over the top of the hook.


With any luck I'll be able to get out tomorrow evening and go for a test flight or two. Will see if I build up the nerve to try it with the bungee and hook.... and if I get the Vector where I can trust it maybe even daggad's autopilot assisted launch... The thing is, after I put a 4S in it I don't think I even need these things...but it's fun messing with it.

daggad
9th October 2014, 02:13 AM
I am quite sure 4S will be something else if you fly on 3S now. :)

Flyswamper
9th October 2014, 08:05 AM
Yeah... I mentioned it earlier but it's understandable that you guys don't hang on my every comment. :) The quick summary is...

....originally got motor/prop intending to go 4S route
... got plane together but didn't yet own a 4S battery...decided to try with 3S
....initial flights with 3S were without fpv gear, with a nice headwind to launch into... went really well
....added fpv gear and tried to launch with no wind...resulted in bent up nose section and failed launches
.....bought a 4S and launched...plane nearly leapt out of my hand...pretty easy to launch (did have some light wind)
.....made a few flights, had a spectator present and I managed to fly into a power line with the spectator watching
.... repairs made (biggest was replace an elevon), the ET Vector installed, added a second 4S battery
.... last night added the hook mainly "because I could"
.... currently waiting on first post-repair-with-vector flight hopefully scheduled for this evening.


So.... I'm hoping/thinking that if I keep the 4S setup I probably won't really need the hook and bungee launch setup. Having said that I guess I just enjoy the tinkering and once I saw your pictures and knew I wouldn't be flying last evening I figured I'd give it a go at installing a hook. I guess I'm thinking I might as well try out the bungee method and see if I like it. Who knows, it might even let me run with a 3S setup again (not sure if I'd want to...but options are always nice to have). Of course, it does add yet another bit of weight...

I'm actually hoping that I can kind of combine the bungee with the 2D autopilot mode method once I get the vector to where I trust it.

billyd
9th October 2014, 11:59 AM
Yeah... I mentioned it earlier but it's understandable that you guys don't hang on my every comment. :) The quick summary is...

....originally got motor/prop intending to go 4S route
... got plane together but didn't yet own a 4S battery...decided to try with 3S
....initial flights with 3S were without fpv gear, with a nice headwind to launch into... went really well
....added fpv gear and tried to launch with no wind...resulted in bent up nose section and failed launches
.....bought a 4S and launched...plane nearly leapt out of my hand...pretty easy to launch (did have some light wind)
.....made a few flights, had a spectator present and I managed to fly into a power line with the spectator watching
.... repairs made (biggest was replace an elevon), the ET Vector installed, added a second 4S battery
.... last night added the hook mainly "because I could"
.... currently waiting on first post-repair-with-vector flight hopefully scheduled for this evening.


So.... I'm hoping/thinking that if I keep the 4S setup I probably won't really need the hook and bungee launch setup. Having said that I guess I just enjoy the tinkering and once I saw your pictures and knew I wouldn't be flying last evening I figured I'd give it a go at installing a hook. I guess I'm thinking I might as well try out the bungee method and see if I like it. Who knows, it might even let me run with a 3S setup again (not sure if I'd want to...but options are always nice to have). Of course, it does add yet another bit of weight...

I'm actually hoping that I can kind of combine the bungee with the 2D autopilot mode method once I get the vector to where I trust it.


There seems to be a bit of resistance on the boards to using bungee launchers. They're kind of looked at like training wheels to some. I have the complete opposite opinion. I launch all my planes with one. It's easier, more reliable and one less thing to have to worry about (am I going to get a good throw, or is the plane going to dive into the dirt).


I fly with 3d video almost exclusively, using the DK1 (occulus rift). With its super wide field of view, and full depth of realism, wearing those goggles and trying to throw the plane will result in me doing a faceplant. Because you get very dizzy unless you're sitting down or have something to lean against while flying. So I launch sitting down. With one foot on the launch pedal and two hands on the sticks. Once I have a plane dialed in I never have a problem with the launch. It is stress free and very easy to set up and use.


On top of that, it is very cool to be sitting on the "runway" under the goggles and ready to takeoff. It adds another level of immersion of flight, which is really the main purpose of FPV.

daggad
9th October 2014, 01:12 PM
Sounds great billyd (in norwegian that nick means "car sound") and everyone should go for what they like and enjoy. It would be fun to see how FPV was on the Oculus Rift, are you using Nerdcam3D ?
I am too lazy to make and bring a bungee myself... ;)

billyd
9th October 2014, 01:17 PM
Sounds great billyd (in norwegian that nick means "car sound") and everyone should go for what they like and enjoy. It would be fun to see how FPV was on the Oculus Rift, are you using Nerdcam3D ?
I am too lazy to make and bring a bungee myself... ;)


T3D.


I can't throw the big wings without messing up. Just easier to let the bungee do it.

Flyswamper
25th November 2014, 02:50 PM
Post mortem on this..... I ended up building an ultra portable bungee launcher and getting comfortable with it. Now that I got the launcher working and ET Vector tuned ..... I've also gotten comfortable with a hand launch assisted by Vector as described earlier. A few more tosses and I'll probably be comfortable tossing over the head even without Vector as a bit of safety net.

The newbie has learned a little :)

Flyswamper
30th November 2014, 08:25 PM
Uhhh.... I was saying what again... :) :(


I think I jinxed myself... he he



http://www.youtube.com/watch?v=6Qkw_iOQ6Vo




Gonna have to break out the big bottle of glue... or perhaps Ritewing sells the center section. :)

fireflyer451
30th November 2014, 09:00 PM
Hey man, I think you hurt that farming machinery.....

Get your bungee back out and reduce your stress. I don't know why more folks won't use a bungee. I am 100% successful with wings 2700 to 3400 grams.

Flyswamper
1st December 2014, 12:20 AM
Hey man, I think you hurt that farming machinery.....
I think only its feelings were hurt... it will recover. ;)




Get your bungee back out and reduce your stress. I don't know why more folks won't use a bungee. I am 100% successful with wings 2700 to 3400 grams.

Sounds like pretty good advice to me right now ;)

billyd
2nd December 2014, 08:52 PM
You see!! I told you lol. Sorry man. Anyway, I accept my limitations and stick with the bungee. Haters gonna hate lol

Wise_Man
3rd December 2014, 01:39 AM
What are you guys using as the bungee cord: Latex? Silicone? What diameter? How long? Vendor? Additional tow line?

Flyswamper
3rd December 2014, 10:46 AM
I'd be the last one to suggest my bungee setup is what you want to copy but... since I started this thread and mentioned I did manage to cobble together a working bungee.... thought I'd share what I did... I've had intentions to take some pictures and show my poor-boy/cobbled-together bungee launcher setup but I haven't yet taken the time to do that.

Being impatient and willing to cobble stuff together, my first bungee cord was actually just made from using Duct-tape to hold together 4 or 5 of these bungee straps that I found in the local HomeDepot

http://www.homedepot.com/p/Keeper-48-in-Flat-Bungee-Cords-2-Pack-06104/202065678

(mine are green, but essentially the same)

I simply hooked them end-to-end and used the duct-tape to keep the ends together and also serve as protection in case the cords came flying back at me (the duct tape covers up the "sharp hook ends").

Together with some simple stakes and a PVC ramp that I just friction-fit together when I get there, I ended up with a very portable setup.


Later, I went online at HomeDepot and ordered this longer bungee cord:
http://www.homedepot.com/p/T-W-Evans-Cordage-1-4-in-x-50-ft-Elastic-Bungee-Shock-Cord-SC-104-050/205327121

I've used this once. It worked, but the pull wasn't as strong as I think I need it to be (the plane almost got to the ground). If I'm going to use this cord again I think I'm going to want to double it up so that two strands are pulling the plane off the ramp. If I were doiing it again I'd probably get a thicker gauge cord in the first place. As it is... I'll either use the cord I have doubled up, or I may just go back to using the duct-tape attached straps as they seemed to have plenty of pulling power and the launches I did with that setup were quite nice. It just looks more like an Aggie-engineering setup (and I'm a Sooner grad so gotta avoid all things Aggie... especially this weekend when my sooners have their bedlam game with the aggies... ha ha)

Now... hopefully one of the guys that knows what they are doing will chime in with better answers. :)

fireflyer451
3rd December 2014, 11:11 AM
I am using this one: http://www.aerofoam.com/zipstarts-catapults.htm - Item Number: Stnd1/2x24 . I had another that I put together myself but it was not strong enough for heavier birds. I did not put much time in research/design, so..... I got what I paid for.

This one from aerofoam is top notch, very high quality all around. I know you might say 'what quality, its a frigging rubber hose!'. The rubber is high quality, I can tune the pull very easily and I have no worries about breaking the hose/string/etc. It is a nice piece of kit, if I build another one myself I've got a good model to base it on.

ritewing
3rd December 2014, 11:52 AM
I also use the Aerofoam , 1/2 and 5/8 size dep on the plane
The don't crack after 3 months, they last years.

billyd
3rd December 2014, 11:59 AM
I use a modified Jetapult from these guys: http://fliteevolution.com/product/bungee-launcher/


It's just a jetapult http://shop.rc-electric-jets.com/Jetapult-Complete-System-Jetapult-1.htm with an additional bungee tied to the original bungee to make it longer, and taller pvc tubes to allow for larger aircraft.


Couple minutes to setup and very reliable.


Of course you can make one yourself very easily for about half the cost if you're not lazy like me.

Wise_Man
3rd December 2014, 05:05 PM
I am using this one: http://www.aerofoam.com/zipstarts-catapults.htm - Item Number: Stnd1/2x24 . I had another that I put together myself but it was not strong enough for heavier birds. I did not put much time in research/design, so..... I got what I paid for.

This one from aerofoam is top notch, very high quality all around. I know you might say 'what quality, its a frigging rubber hose!'. The rubber is high quality, I can tune the pull very easily and I have no worries about breaking the hose/string/etc. It is a nice piece of kit, if I build another one myself I've got a good model to base it on.

Yes, that seems to be top of the line but I find it quite expensive for a short rubber tubing (is it about 15 ft by the way?) and some standard mason line.

fireflyer451
3rd December 2014, 08:25 PM
Aerfoam 1/2" model: 25' of rubber , 25' of line. Rubber end has hook for ground stake, string end has ring for attaching to plane.

Manzooka
9th December 2014, 03:37 PM
I've been able to hand launch my ZII without too much trouble but I keep having really close calls on my Z3. This thread inspired me to try my hand at a bungee setup so I threw this together after viewing some pictures of online options. Seems pretty straight forward. It's surprisingly sturdy and should be more so with a couple of tie down stakes attached.

I'm going to pair it with the aerofoam bungee and hope for the best. :cool:

https://dl.dropboxusercontent.com/u/551260/ZII/bungeelauncher.jpg

billyd
9th December 2014, 07:58 PM
I've been able to hand launch my ZII without too much trouble but I keep having really close calls on my Z3. This thread inspired me to try my hand at a bungee setup so I threw this together after viewing some pictures of online options. Seems pretty straight forward. It's surprisingly sturdy and should be more so with a couple of tie down stakes attached.

I'm going to pair it with the aerofoam bungee and hope for the best. :cool:




You might be able to shorten up the front legs. Really only need about a 15 angle for launch. Also, you will want to cut off the outer tubes at the end so they don't form a full circle. The top third of the pipe, so it's an open "U" section. Otherwise it may catch on your plane.

Manzooka
9th December 2014, 08:09 PM
You might be able to shorten up the front legs. Really only need about a 15 angle for launch.

Already have, but thank you. That's 18" PVC nipple pipe in the photo and I've replaced it with 10". Once I had the release mechanism assembled and installed I could tell that I'd be putting some pretty awkward forces the wing and launcher on release.

billyd
9th December 2014, 08:15 PM
Already have, but thank you. That's 18" PVC nipple pipe in the photo and I've replaced it with 10". Once I had the release mechanism assembled and installed I could tell that I'd be putting some pretty awkward forces the wing and launcher on release.


Looking good. Did you notice my edited response?

Manzooka
9th December 2014, 09:29 PM
Looking good. Did you notice my edited response?

It's really hard to see in the pic above because it's all washed out, but the two front top connectors are clips rather than fully rounded T-joints. They clip onto the PVC leaving the top open. Thanks though, I can't help but imagine what might happen during a launch with the ridge left in place :rolleyes:;)

http://images.lowes.com/product/converted/025528/025528761738lg.jpg

billyd
10th December 2014, 09:47 AM
It's really hard to see in the pic above because it's all washed out, but the two front top connectors are clips rather than fully rounded T-joints. They clip onto the PVC leaving the top open. Thanks though, I can't help but imagine what might happen during a launch with the ridge left in place :rolleyes:;)

http://images.lowes.com/product/converted/025528/025528761738lg.jpg


LOL sorry for being captain obvious but in the land of backward props, inverted gyros and reversed polarities, anything is possible. ;-)

Manzooka
23rd December 2014, 07:40 PM
I tried my bungee launcher for the first time this afternoon and it works perfectly! :D I just guessed on the amount of tension needed but both the ZII and Z3 took to the air without issue. A buddy of mine took some video but I don't have it to share at the moment, hopefully later.

Aquasean
31st January 2015, 12:09 PM
Does any one have a picture or video they could share of their Z3 bungee launcher, hook, and launch?

RonSII
31st January 2015, 06:52 PM
I believe Ian had quite a few pics about halfway through his Hello Kitty (http://fpvlab.com/forums/showthread.php?7083-ZII-Project-Hello-Kitty) thread and I remember quite a few other threads on here specifically about launchers and release techniques.

Manzooka
1st February 2015, 10:29 AM
Aquasean,

There's a pic of the launcher I put together a few posts up, although I've since shortened the black tubing to cut that angle by more than half. For the "hook" I just glued a piece of CF rod into the underside nose nub. Not the best pic but I think you'll see what I mean...

https://dl.dropboxusercontent.com/u/551260/ZII/thing.jpg

I'm using the aerofoam 1/2 inch bungee and it works perfectly, but now that I have it I wish I just made my own for a quarter of the cost. Here's a vid of the first launch with a Z3. Effortless.


https://vimeo.com/118400919

Aquasean
4th February 2015, 12:19 AM
Manzooka,
Thank you for sharing the photo and video.

If you didn't have the carbon fiber rod as a hook what else would you use?

Flyswamper
4th February 2015, 12:41 AM
If you didn't have the carbon fiber rod as a hook what else would you use?


Have a look at what fireflyer showed that he did in post #30 of this thread. I ended up going to HomeDepot and getting the exact same hook and using it. My attachment (see post #34 of this thread) was slightly different with the wood and glue, but it was the same hook and it worked well.

Manzooka
5th February 2015, 02:07 PM
I'm using that same Home Depot hook on my Z2. Mine is attached directly to the foam with gorilla glue and then covered in a top layer of Goop.

P.I.Engineer
6th July 2015, 06:27 PM
I finally have my hand launches dialed, i'm using an elevator uptrim mix for launch, i turn it off once i'm in the air and in control.

Originally, i was using switch B down to turn it on, but it was a bit fumbly to turn off while gaining control.

I read about the sticky command and did a bit of slick taranis programming.

I fly APM and use rudder arming, so right rudder for 5 seconds to arm the motor.

My sticky method is
-hold left rudder and momentary switch for 2 seconds
-this activates the mix and plays and alarm so i know it's active.
-move the rudder full left turns off the mix and the alarm.

my mix addition number is arbitrary, use what works for you.
i also don't have my radio or the path described, so do what want for an alarm.

Flateric
24th October 2015, 10:27 PM
Hey man, I think you hurt that farming machinery.....

Get your bungee back out and reduce your stress. I don't know why more folks won't use a bungee. I am 100% successful with wings 2700 to 3400 grams.

My problem/fear is....

I have a bungee made, have my hook mounted and could use it to launch, but have these horrible images of the bungee pulling the wing into the ground from release and dragging it along violently shedding parts of my z3 every which way as it goes resulting in a final z3 that resembles a apple core with a bungee hook attached to it with little shreds of the color of my wings were clinging to it. Hows that for an image for you?

Flyswamper
25th October 2015, 10:27 AM
but have these horrible images of the bungee pulling the wing into the ground from release and dragging it along violently shedding parts of my z3 every which way as it goes resulting in a final z3 that resembles a apple core with a bungee hook attached to it with little shreds of the color of my wings were clinging to it. Hows that for an image for you?

I understand the fear and mental images. The Z3 was my first "big" flying wing. Sadly she is retired now from too much nose damage and me being tired of fighting with it and repairing it. What I will say is that I believe if I'd have gone with the bungee from the first, I'd probably still be flying her today. I never sustained any damage during bungee launches. I did sustain plane-retiring amounts of damage to the nose and center section from far too many occasions where I tried hand launches and because of lack of speed/airflow the plane would stall and rollover, nosing into the ground. Make sure you have that hook at an appropriate place relative to the CG ( I forget what the exact guidance is... isn't it something like 1/3 of the way ahead of the CG point) and the bungee cord will keep the nose forward and the planes weight will keep it with a nose-up attitude.... and the bungee will give it enough airspeed to get it going without a stall and rollover.

Oh and once you do get her launching/flying nicely with the bungee, remember to keep your speed up on landings too. Some of my nose damage occurred via the exact sort of slow-speed stall and rollovers occurring at launch and during landings where I tried to come in too slow. Save your Z3... use the bungee and keep her flying fast enough to avoid stalls on launch and landing!

billyd
7th December 2015, 05:20 PM
Hi Guys I just uploaded a couple of 3D print designs for tow hooks (for bungee launchers)

http://www.thingiverse.com/thing:1178217

EHLO
8th December 2015, 01:36 AM
Hi, how do you fix your hook ? Glue it to the laminate ?

Hi Guys I just uploaded a couple of 3D print designs for tow hooks (for bungee launchers)
http://www.thingiverse.com/thing:1178217

Here is what I came up with:
http://www.thingiverse.com/thing:1063351
(http://www.thingiverse.com/thing:1063351)

billyd
8th December 2015, 09:26 PM
Hi, how do you fix your hook ? Glue it to the laminate ?


Here is what I came up with:
http://www.thingiverse.com/thing:1063351
(http://www.thingiverse.com/thing:1063351)

I notch out the foam so the printed part drops in about 3-5mm and use Goop glue (after roughing up the printed part's base).

ritewing
9th December 2015, 10:02 AM
Goop melts epor

billyd
9th December 2015, 10:20 AM
Goop melts epor

Yeah on epor you should use something else.

ritewing
9th December 2015, 10:29 AM
I glue the hook to the lam with hot glue, then goop around its perimeter. The lam is what is stuck to the epor directly as the buffer

crashsalot
10th December 2015, 12:46 PM
I use the method shown on the aerofoam site, piece of wire taped on. Never failed, reversible.
What hasn't been mentioned before is if your thrust angle is off (pointing back-downwards) you'll
have a hard time gaining height during launch, even with plenty of thrust, because it's pushing the nose down.
The Z3 is unlikely to have that problem though (tough motor mount).

billyd
17th February 2016, 04:41 PM
I bungee launch without power and apply power after ring separation from the hook. Less chance of a tangle. With that approach if you mount the hook about 2/3rds the distance from the nose to the CG you get a nice upward launch naturally, in my experience. This keeps the thrust angle out of the equation.

mutley2
13th March 2016, 01:03 PM
I've been asked a number of times on how I launch the Z3 spade, it's really straight forward, I just launch/throw in a traditional way. No real expertise is need just a confident throw, more like a guided throw as the Z3 has more than enough power. My Z3 had 2 Mobius's fitted and there was zero wind, so it's worst case scenario, no problems though.

http://www.youtube.com/watch?v=9mRQE0rVkuw

Pushjerk
13th March 2016, 01:34 PM
Thats killer, Mutley. Do you have a finger hold on the underside? She just goes up. 10x6 SS combo?

Here is a quick clip of my maiden launch. Classic style, 10x6 SS - a little bit of sag after the initial punch, but she climbs out quite quickly and gracefully. Looking back, it's apparent how jittery and nervous I am. And I don't have any groovy music.

Of note, I have a tad bit of up elevator on a switch, Vector is in 2D No Hold.


https://vimeo.com/146974427

i have since been flying with a 10x5, and it just shoots off like a rocket - no bias toward the ground at all. Haven't noticed any real detriment to efficiency in my locale.

mutley2
13th March 2016, 02:58 PM
Hey pushjerk, no finger hold as I use the "o" ring that attaches the wings to give a little bit of grip. It looks like I'm throwing the Z3 but I'm not, it's just a little guild and off she pops.
I fly throttle right so I hold a little bit of up elevator in, just for a few seconds and to stop the sag after release, with a 4s 1300Kv HK motor 80Amp ESC it does not lack for power.
59 seconds in the slow-mo shows my hand is well clear, hope this helps any one that had Z3 launch worries, she's a pussy cat to launch.

http://www.youtube.com/watch?v=9mRQE0rVkuw

Vassa69
25th April 2016, 06:08 AM
Haha sweet song :P Heres my complication. The crashes i had were when i was a newb and was to puzzy on the throttle. I do it chris style and that never failed on me.


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

Thatguymike
25th April 2016, 01:30 PM
Factors:
Wing loading
arm strength
headwind
power available
technique

word