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Learning to use a Hi-Start to launch your glider

Old 09-27-2010, 06:50 AM
  #76  
Huffy01
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I am intending to make a stake out of a fencing dropper but I have a 4wd van and a station wagon that are not register for the road so depending on the weather I'll just use a tow bar.
I am on 90+ acres of land so there will be little chance of hitting someone with a spike.
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Old 09-27-2010, 12:50 PM
  #77  
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Humm, I had not thought of that. Actually it is not unusual, when several pilots are sharing the hi-start, for one to be out in the field, perhaps 1/2 way to the stake to pick-up the chute and bring it back for the next launch.

But despited any debate, YES, make sure that stake is long and strong. I typically use a 12 inch spike which I pound in at about a 30 degree angle away from the pilot with about an inch sticking up to take the ring/washer attachment and to allow it to swing as the hi-start is adjusted for the wind.

With this angle, as the pull increases the tendency is for the rubber to pull down toward the ground rather than up. and any pull pressure will tend to be distributed along the length of the spike into and against the ground.

Never had one come loose.
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Old 09-27-2010, 08:04 PM
  #78  
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I also used a 12" spike driven the same way. Never had one pull loose even in the Florida sand.

I used a 24" stake in beach sand though. Then I was using elastic only with no fishing line, with parachute fastened to the ring on the end of the elastic. I had less spectator control there and was taking no chances.
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Old 10-09-2010, 06:40 AM
  #79  
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Fianlly spring has arrived, one month late. It gave me sometime betwwen races at Bathurst.
The first pull I only got to 2.17kg before one of the joints failed.
After replacing the dowel with a longer piece of dowel I got to 3.67kg before the other dowel joiner failed.
I haven't got anything to measure the distance so I had to pace it out.
The silicone bungee is about 32 paces long and managed to stretch it 65.5 paces.
So that's 97.5 paces from the anchor point at 3.67kg.
Is this going to be good enough to launch my 3.2m Stepp Upp its all up weight was 2.2kgs
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Old 10-09-2010, 04:10 PM
  #80  
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Originally Posted by Huffy01 View Post
Fianlly spring has arrived, one month late. It gave me sometime betwwen races at Bathurst.
The first pull I only got to 2.17kg before one of the joints failed.
After replacing the dowel with a longer piece of dowel I got to 3.67kg before the other dowel joiner failed.
I haven't got anything to measure the distance so I had to pace it out.
The silicone bungee is about 32 paces long and managed to stretch it 65.5 paces.
So that's 97.5 paces from the anchor point at 3.67kg.
Is this going to be good enough to launch my 3.2m Stepp Upp its all up weight was 2.2kgs
Sorry if I missed it, but you dont describe a high start that I'm used to. The typical hi-start rig is 1/3 bungee, and 2/3 string.

If your 'all up' distance is only 97 paces, once that tubing begins to shrink, the altitude gets compromised. Plus, the heavy tubing will weigh it down.

If you have the long string attached, the 3+ kg is plenty of pull.
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Old 10-09-2010, 05:20 PM
  #81  
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I haven't attached the line yet. I was just stretching the bungee.
I have 150m of 80lbs fishing line and a hot pink parachute to go on the end.
I just need a descent ring to go at the end of the parachute.
I did buy some from the hardware store but they are about 28mmX5mm and solid zinc coated steel.
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Old 10-11-2010, 02:23 AM
  #82  
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As stated earlier in this discussion, typically for a thermal duration glider with the hook placed near the CG, you want a pull of at least 3 times the weight of the glider. Less than that and you are not likely to get a relable launch except in a strong breeze. Even then it would be as high as you would like.

Also, my hi-starst have 3 to 5 times as much string as rubber. So a 30 meter hi-start would have 90 to 150 meters of line.
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Old 06-29-2011, 03:20 PM
  #83  
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Sources for hi-starts and hi-start rubber
This needs to be updated from time to time.

My favorite, NESailplanes seems to be in trouble. No one seems to be able to get in touch with them, so forget the Pinnacle hi-starts.


OTHER SOURCES

Hobby-Lobby - hi-start rubber or full hi-start packages - well known for quality products
http://search2.hobby-lobby.com/psear...-start&x=0&y=0


Aerofoam - Hosemonster - rubber alone or full packages
reputed to be the best
http://www.aerofoam.com/hosemonster.html


HobbyKing - rubber only. I don't know much about these. 30 foot pieces only so you would have to join them for a larger HS.
http://www.hobbyking.com/hobbyking/s...wer_Search.asp


I found this e-bay listing for theraband
http://cgi.ebay.com/ws/eBayISAPI.dll...m=190544596819
I posted a question to see if the spools are 100 feet continous or if it is pieces. 100 foot of green is $53 including shipping. A guestimate would be that red would be good for 2M, Green for typical 3M, Black for extra strong or larger than 3M. Anyone have actual pull measurements for this stuff?


Tower Hobbies - Low cost - they work but I only recommend these for people on a very very tight budget. Use the HD for 2M or above. Probably Ok to 100" wing span. Standard is for under 2M gliders.
http://www3.towerhobbies.com/cgi-bin...EARCH=hi-start


General guidelines

You can buy latex rubber tubing on e-bay or from other sources, just make sure that whatever length they offer is one piece. You can see offers for 100 feet but it comes as a bunch of 5' sections which would be common use for this stuff. You can join pieces but I would not want more than two joiners on a 100 foot hi-start. There are joiners that can be split so having multiple pieces could be an advantage if you fly on varying length fields.

Assuming you find 30, 50 or 100 foot pieces here are the size breakdowns as I have seen them used. Others may provide different advice. I tend to like my HS a little stronger. You can always pull a little less but if you need more pull and you don't have it you are stuck.


5/16" OD - Standard HS good for about 1.7M up to about 3M or about 65 ounces.

3/8" OD - HS for up to about 3.5M or about 80 ounces. Fine for 2M planes, just don't pull as far.

1/2" OD - Good for up to about 4M or about 100 ounces. May not be good for 2M planes.

Note that if you are going to hi-start launch a 80 to 100 ounce plane, about 5-8.25 pound planes, your high-start will be pulling at 25 to 40 pounds. That would be difficult for one person to handle so it would be best to have someone handle the plane while someone handles the radio. Planes of this weight are better suited to a winch, but you can hi-start launch them.
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Old 06-29-2011, 04:12 PM
  #84  
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I used a Dynaflite Heavy Duty from Tower for over 10 years with no problems. It's 25 years old now and the rubber is shot, but with new elastic I could use it tomorrow. I flew 2 meter planes with it.

Having never flown a higher quality one, what is the difference? There isn't a whole lot of difference in price either if you were also considering one from Hobby Lobby.
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Old 06-29-2011, 04:27 PM
  #85  
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I now use shock cord "bungee". Its very weather proof and very strong, you can actually roll it up wet and it will not degrade it. You have to adjust your pullback distance compared to the rubber tubing distance. But I have had great success with this stuff..and its last a very long time. You can get about 300feet of it for around 40 bucks.
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Old 06-29-2011, 07:13 PM
  #86  
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Originally Posted by Rockin Robbins View Post
I used a Dynaflite Heavy Duty from Tower for over 10 years with no problems. It's 25 years old now and the rubber is shot, but with new elastic I could use it tomorrow. I flew 2 meter planes with it.

Having never flown a higher quality one, what is the difference? There isn't a whole lot of difference in price either if you were also considering one from Hobby Lobby.
The HD is great for 2 to 2.5M and light 3M gliders, but once you get above about 60 ounces it just doesn't have the umph you need. One of our members has one and it hardly luanched is 58 ounce Bird of Time.
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Old 06-29-2011, 08:09 PM
  #87  
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Okay, so it's good for what its real capabilities are but Heavy Duty should be "Heavy Duty" in quotations with a smile. I'm not surprised there. Thanks!
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Old 03-31-2014, 05:17 PM
  #88  
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A few more examples of hi-start launches:

https://www.youtube.com/watch?v=JghL7LRFQoo

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

Hi-starts are not just for little woodies. The Nan Shadow is a high end composite competition glider
https://www.youtube.com/watch?v=RGHcya0WPEQ


Mike Smith is a world class competition pilot.
https://www.youtube.com/watch?v=mTd3PGC8zOs
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Old 03-31-2014, 06:09 PM
  #89  
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Here's back in 1980's ......

Apologies for video quality but it's 8mm cine converted ...

[media]http://www.youtube.com/watch?v=rU0Ke1Fbmvk[/media]

Nigel
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Old 11-20-2014, 02:26 PM
  #90  
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Just came across a hi-start at Horizon hobby. FYI
http://www.horizonhobby.com/parkzone...0-2-3m-efla650

Includes a good video on how to use a hi-start
https://www.youtube.com/watch?v=ru0tyLi6L74#t=43
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Old 07-03-2015, 08:15 PM
  #91  
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Originally Posted by AEAJR View Post
Do you avoid contests because they are flown off winches and you practice on a hi-start? Let me give you a different prospective. If you don't fly contests you are missing out on a lot of fun.


Our club contests and our Eastern Soaring League contests are all done off
winches. However anyone can have their plane launched for them off the
winch if they are not talented on a winch. I did this for several Novice
class flyers at a recent ESL event. In my first ESL contest others launched the plane for me.

Are you at a competitive disadvantage if you don't have a winch to practice on? Sure, but compete anyway!

There is no question that a super strong ship can achieve greater height off
a winch than a hi-start. And there is no question that a typical sport
class plane can not take the stress of the extreme zooms that the super
competition class planes can handle.

Having said that, I say, who cares? I compete in club and Eastern Soaring
League contests. I may never win either but I have so much fun at the
competitions it really doesn't matter if I win. And I get so much support
and good coaching from the advanced pilots that I would have to be a fool
not to compete. These are flying lessons from the best!

I share what I learn with those who want it. They can use it in whatever
way they wish. But the idea that you can't compete because you don't have a
super ship just does not cut it with me.

I was at my first Eastern Soaring League with a Sagitta 600 2M RES glider.
The only 2 meter in the contest. I finished dead last, but I finished.
Some others did not finish. I had a grand time and I was a better flyer for
it.

I did most of my practice flying off a Hi-start! At the contest other flyers launched my plane off the winch for me. Worked out fine and they were happy to do it.

I then got a 15 year old Airtronics Legend that flies like a tank. 4
contests on that one. It is now my back-up plane. I have managed to move up to NEXT to last. Having a frickin ball!

On the Legend, I practiced on the winch and on the hi-start.

Now I have a PoleCat Thermal Dancer. Still not an Icon or a Supra or a
Sharon. Maybe I can achieve mid pack. That would be nice, but frankly I am always flying for my personal best. Perhaps someday that will get me a prize. But when I make a personal best, it always makes me smile. Hitting the center of the landing circle is such a high!

I encourage you and other flyers to enter contests for the fun, for the
friendship and for the learning. And, if you are an active contest pilot, I
encourage you to take that hand of a reluctant flyer and bring them into the
contest fold. Believe me they will thank you.

Clear Skies and Safe Flying!
I was on a 1,500 mile bike ride and took a break at a park that was doing a glider competition. Back then they used a starter from a old Chevy with a foot switch. The poor people used a bike with the rear tire removed, upside down. They only made ten speeds during that era. Everything was balsa paper and dope. Now it's foam. The good old days!
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Old 07-03-2015, 08:25 PM
  #92  
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Default I use key rings.

Originally Posted by Huffy01 View Post
I haven't attached the line yet. I was just stretching the bungee.
I have 150m of 80lbs fishing line and a hot pink parachute to go on the end.
I just need a descent ring to go at the end of the parachute.
I did buy some from the hardware store but they are about 28mmX5mm and solid zinc coated steel.
Try using key rings. The string is just to keep the stake from hitting the control guy in the event the stake comes out of the ground or the tubing breaks. Make sure the key rings are strong but will come off the plane. I have the instructions and a hi start. The knots were the hard part for me.
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Old 08-28-2015, 06:38 PM
  #93  
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Default My wife is my launcher.

Throw the plane hard with the nose up at around 45 degrees or higher.

It took some time to get my wife out of the house to launch for me but she's under five feet tall and doesn't seem to understand keeping the wings level during launch. I started with her flying flat and worked it up on each launch to around 45%. When I got back home she said the best launches were just tilt to the angle and let go. 450' of line with a parachute, 1/4 tubing, 3/4 string. That's just to keep the stake from going between the eyes if it were to come out of the ground. So I am told. We had nine great launches. Some were hard to recover from on that boost. One I was stuck on the high start. It didn't want to let go so I did a dive and hard up. It came loose and it was fun too.

How do you feel about launching at a 45% angle with no toss? Just tenshion on the line and let it go to make sure the wings are level?

Some minor repairs and I'll be ready to launch again. Trial and error seems to be my downfall.


Originally Posted by AEAJR View Post
Maximizing Launch Height Using a Hi-Start
by Ed Anderson
aeajr on the forums

While the winch is the preferred method to get the most height on a launch,
you can get awesome launches off a hi-start if you know what to do. The
advantage the winch has is that you can control the pull throughout the
launch. With a hi-start, the pull is maximum on initial release then
decreases throughout the launch. But that does not mean that you can not use the same techniques the winch launchers use to gain extra height.


ELEVATOR AND CG

The further back the CG, the easier it is for nose to come up during the
launch. If your plane tends to launch fairly flat and you find you need up
elevator to get it to rotate, try moving the CG back slightly. Then fly the
plane. It will be more responsive and will read lift better. You may find
that you have to add some down trim after moving the CG back. This is
because you have been using up trim to hold up that heavy nose. This
process will reduce drag and make for a better flying plane.

I usually start my gliders at the most forward CG recommended by the MFG,
then over a series of flights, I move it back till it gets too twitchy to
handle, then I move it forward a little till it gets stable enough for me to
fly it. Many competition pilots have the CG so far back that I can not
handle their planes.

If you have a computer radio, try adding some expo. This will soften the
response around the center of the controls making it easier for you to
manage smooth flight with a plane that has a more rearward CG.

You should not have to apply any elevator during the launch. If you are,
then you are introducing drag which reduces speed and does not increase
lift. Try working your CG back and see how it flies. It will launch better
when the CG is further back and you will need little or now elevator to get
the nose up. The placement of the tow hook will likewise impact the need
for elevator on launch. I cover that next.


HOOK AND THROW

Hook placement will make a big difference in your launch height. The closer
the hook is to the CG, the steeper the rotation of the plane during launch.

The optimum situation is that your plane climbs at about a 70-80 degree
angle presenting the most resistance to the contraction of the rubber. This
takes the plane through the largest arch and produces the longest time of
launch, extracting more energy from the pull and translating it to height.
If there is a breeze and your launch angle is steep enough, the rubber may
never fully contract during the launch giving you the greatest height
possible. You will use that remaining tension in the line when I cover the
zoom, later in the discussion.

When you launch initially, if you have enough pull on the line, throw the
plane up at about a 30 to 45 degree angle rather than out flat. This gets
the plane through the rotation faster getting it into this max lift position
sooner. The throw really makes a difference. It gets you up to flying
speed faster which is important the closer you have the hook to the CG.
Typical hook position is about 1/4" in front of the CG, but having it closer
will usually give you higher launches.

Note that , as you move the CG back, as advised above, you are moving
further and further away from the hook, so you may need to adjust hook
position just to maintain your current hook/CG position. Also note that the
further back the hook placement, the closer to the CG, the harder the plane
is to control on launch. It will stall easier on initial release, so it is
vitally important to give it a good throw and not just let go.

When moving your hook back, you may wish to have someone help you during this adjustment phase by either throwing the plane for you, or working the radio. This way the hands are on the sticks at all times. If the throw goes bad or if you have moved it back too far, you will be better able to respond. If the plane stalls on the launch, a little down elevator for a moment will help it gain speed and you may be able to save the launch. Once you have it where you like, you should be able to launch it by yourself.


ZOOM

It is possible to "zoom" off a hi-start, in a similar fashion to what is
done with a winch. The bounce is not as dramatic, but still, you can gain
additional height if you get the timing right.

When the model is about 80% through its arc, and while there is still
tension on the line, rather than just flying off the line, you nose down for
less then a second, then pull up hard. The weight of the hi-start, and any
remaining tension, will help to accelerate the model to a higher speed. The
down/up pull then translates this speed into altitude. I do this with all
my planes. The Spirit, the most fragile of my gliders, picks up at least 50
feet this way. With a moderate breeze and a fast plane, you can do even
better. If you have an aileron plane or aileron/flaps, and a computer radio
that will allow you to reflex the wing, this can help you gain even more
height.


CHANGING THE WING

If you have flaps, deploy them on launch. If you have ailerons and a
computer radio, then drooping the ailerons also will add even more lift upon launch.

By creating more under camber, more bottom curve, you create an airfoil that
produces more lift. It also produces more drag, but during the launch, when
you have the pull of the hi-start, you can afford this drag to gain the
lift. This will create a longer arc and a higher launch.

Launch - Flaps or flapperons down for initial launch: Usually 10-20 degrees
is enough, but every plane is different, you have to experiment. I have seen
launch positions as high at 45 degrees on the flaps. If you have the
ability, droop the ailerons too.

Throw the plane hard with the nose up at around 45 degrees or higher.

Mid arc - If you have a computer radio and can set a reflex position, about
70% up the line you switch to reflex. This is where the ailerons/flaps are
actually moved up slightly from their normal position. On most airfoils,
the RG15 foil being a know exception, this creates a high speed/low
drag/lower lift setting that is great for gaining speed. Now you want to
accelerate the glider to gain speed.

Zoom - Around 80% though the arc you do the down/up while at maximum speed,
still in reflex. The down lasts less than a second and the up is strong.
Go for a climb angle of 60-90 degrees, depending on the plane and the pilot.
You have to experiment to see what works best for you.

Level - As it climbs it will lose speed. Before the plane loses all its
speed, you level the plane, go to normal wing position and start your hunt.
If you are stalling at the top of the launch, resulting in a drop in the
nose and loss of height, then you are waiting too long to level the plane.
It should look like the plane just leveled onto a table with no drop of the
nose. This is your best launch height.

You can still zoom with a simple 2 channel plane, but if you can change the
airfoil during the launch, you can gain even more height. If you have
flaps but no computer radio, you can still go though this sequence using the
flaps. Where I call for reflex, just move the flaps to normal flying
position. Ahhhh, the joy of computer radios.

Using a winch, this sequence can gain 150-300+ feet, if you have a strong
plane. It can be quite dramatic.

Using a full size hi-start with enough pull, you can do about 25-50% of
that. The limiting factor is that you can't increase the power at the end
of the launch like you can on a winch. However you are also unlikely to
overstress the wings off a hi-start. I have seen planes fail on zoom, using
a winch, when the pilot was too aggressive on the zoom. I have never seen a
plane fail when zooming off a hi-start, but I am sure it can be done.


GIVE IT A TRY!

If you go through all the steps above, you may find that you are getting
higher launches without the zoom. This is great!

Then you can try adding the zoom, but tune the CG and hook positions first
as these are more important. But you can try a zoom on any plane, the
benefits will just not be as great as when the plane is tuned properly.

If your plane drops at 100 feet per minute during its glide, and you can
gain 50 feet on the launch, you just gained 30 seconds of flight time. And
thermals tend to be larger in radius the higher you go, so you have a larger
target. If you can gain 100 feet, the flying experience can be quite
different.

The more sophisticated the plane and the more flexible the radio, the more
you can tweak the launch. The longer and stronger the hi-start, within
reason, the higher your launches.

Even with a simple R/E plane, you can improve your launch height by going
through these steps. You will get higher launches, longer glides and likely
find more thermals than you did before.

Other resources can be found in the handbook. I hope this has been
helpful.

The New Glider Pilot's Handbook
http://forums.flyesl.com/topic.asp?TOPIC_ID=251
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Old 08-28-2015, 09:14 PM
  #94  
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Actually depends a bit on the plane and the power of the High-Start.

A light plane with just a little wind and a good High-Start can do fine with the 45 up angle and let go.

A heavier model that will stall it and it will spin in then get dragged and shredded. Heavy models (especially with a lighter pull High-Start and no wind) need a strong toss aimed at the stake, gain a little speed then pull.

There is no one technique that is guaranteed to be right every time... Adjust for the model, the High-Start and the wind.
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Old 08-28-2015, 09:23 PM
  #95  
AEAJR
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Originally Posted by Mkrusz98284 View Post
Throw the plane hard with the nose up at around 45 degrees or higher.

It took some time to get my wife out of the house to launch for me but she's under five feet tall and doesn't seem to understand keeping the wings level during launch. I started with her flying flat and worked it up on each launch to around 45%. When I got back home she said the best launches were just tilt to the angle and let go. 450' of line with a parachute, 1/4 tubing, 3/4 string. That's just to keep the stake from going between the eyes if it were to come out of the ground. So I am told. We had nine great launches. Some were hard to recover from on that boost. One I was stuck on the high start. It didn't want to let go so I did a dive and hard up. It came loose and it was fun too.

How do you feel about launching at a 45% angle with no toss? Just tenshion on the line and let it go to make sure the wings are level?

Some minor repairs and I'll be ready to launch again. Trial and error seems to be my downfall.
The four factors that impact launch:

Weight of the glider
Pull of the hi-start
Position of the tow hook
Amount of wind

You can launch at whatever angle works best for you. This thread is about learning and during learning I would say you should do your first launches flat with the tow hook well in front of the CG and let the glider rotate on its own. Then you can gradually work your way up on angle until you find the angle that works best for you. Then you can consider whether you want to move the tow hook back, assuming you have an adjustable tow hook.


No matter how I launch my Supra, it will rotate almost vertically because of where I have the tow hook, which is optimized for the winch, not the hi-start. I have to be careful not to stall it on the launch even though my hi-start is quite strong.
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Old 04-22-2017, 10:44 PM
  #96  
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Hi Everyone! Been away from flying for a number of years. I have been flying the EF Laser60 ( electric) and some foamies. BUT...My heart is in sailplanes!! Heck I used to own a 2 place Lark so many years ago. I have read this entire thread and lots of other things over the last few months. Since I am semi retired, out of work and have time, I thought I would get back into RC. I flew in an electric glider contest using the Calypso last year and performed very well. I want to get back into silent flight for most of my flying. I have been vacillating between Electric sailplanes and pure gliders. When I watch someone hand laugh the Explorer and find lift, it excites me the way few things can ( for this old man). So I am thinking that to get a good sailplane with a small low power high start, kind of like a super strong arm, would just be loads of fun. Also I would not have to spend $300 ~ $500 on electrics. So the idea of getting a explorer or a shadow ll or a dragonfly-strong.... and using a low power high start seems like a good way to go. Money is scarce these days. So I am wondering how well would a Dragonfly ( soaring USA) do with a high start and how much would I be giving up buying that VS a Sharron or Shadow or Explorer?
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Old 04-22-2017, 11:01 PM
  #97  
Kasperwing
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the planes I am looking at weigh about 60 to 70 ounces with 3.5 to 4 m wing spans.
Would this UP start work? http://www3.towerhobbies.com/cgi-bin...?&I=LXYXK7&P=0

where could i find a little better for not a big increase in cost?

BTW, I am doing this for the fun and challenge. As of now, no one flies gliders around here.
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Old 04-23-2017, 12:11 AM
  #98  
AEAJR
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Not that upstart would not work. It is too light.

At 70 ounces, about 4.5 pounds, you will need about 14 pounds of pull to launch that glider.

You need about 3X the weight of the glider, minimum. That would call for a hi-start with about 5/16" outside diameter rubber, minimum. I would recommend 3/8 rubber.
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Old 04-23-2017, 12:18 AM
  #99  
Kasperwing
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Thanks Ed! Did not expect such a quick response. Any ideas where I could get 3/8" rubber latex/ silicone/ un-obtainium glider launching gear?
and.. would an Up start work well enough to find lift?
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Old 04-23-2017, 12:24 AM
  #100  
Kasperwing
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Another question please. Since this thread first started, a large number of improvements have taken place with motors and batteries. It seems to me that many of these planes need ballast.... and to that end why not just add electric propulsion. It looks like the ballast and electric add the same weight?

I think the electric would offer one to make another approach and possibly lessen the chance one would damage the plane ( when you have no more altitude). Thoughts please!!??
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Quick Reply: Learning to use a Hi-Start to launch your glider


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