High Start Question

[mgardner]

Hey guys....I have a NES Pinnacle Large Hi start, which I use to Launch my open class ships (when the winch isnt available)...the high start has 100 ft of good tubing, and what seems like a million (probably closer to 300-400) ft of flourescent line.

My question is, it seems like the flourescent line might be too long, as there just doesnt seem to be much energy left at the top of the launch...soooo, is there an optimum line length I should consider? I thought about cutting 100-150 ft of line off, and putting a swivel in so I can lengthen it back is desired, but not sure if this is a good idea...the swivel would probably just foul the line....

Another thought...my tow hook position is fixed, so I use the same tow hook position for both winch and high start. This is probably the reason that the plane is flirting with stall on the high start. I manage it with a tad of down elevator..

Thanks for feedback..

Mark

[Ollie]

For best results, the line length should be adjusted for the wind conditions. Less wind should use less line, etc. Making the line length adjustable with snap swivels that allow sections of line to be easily removed or added is a very good idea.

[Quacker]

Histarts don't usually have much energy left at the top. The question is: is all the rubber off the ground? If it is, you are getting a good launch. This can then be improved by dipping and zooming before the top is reached. Doing this translates the energy that is pulling the glider down to forward speed that the zoom will translate into more altitude.

[Dyno Don]

Mark,
You need 400' and you need some wind....
1-3 MPH will get you a wimpy launch..What size is your Rubber O.D or I.D.?? How far are you pulling it back? How big is your Glider /Weight and Span..?? Let me know and I can help you out..I Manufactured HI-Starts before I sold out..
Dyno Don

[CactusJackSlade]

What Ollie Said.

You can get some great heavy duty snap-swivel links at the local fishing/sporting goods store.

I have 400' of line with snap lnks at roughly 200, 275 and 350 feet. Some of this is for wind conditions and some because of smaller launch areas...

CJS

[jrgospod]

mgardner,

I swapped the line out for monofilament. I get a lot less drag on the line when I launch. I now get a straighter line launch without the large bow in the line. I would highly recommend it. Make sure to get a colored monofilament line that you can see on the ground.

John

[AustinTatious]

Sound like your rubber jsut isnt strong enough for the plane you are trying to launch, reguardless of how much line you use, the plane shouldnt barley go up on the edge of stall at the begining.


Austin

http://webpages.charter.net/austinswill/

[Jack Hyde]

Mark,
Why didn't you walk back , stretching the elastic more? The energy stored in the histart is proportional to the amount of stretch squared. When you double the stretch you double the initial pull and double the distance of pull available. Therefore a little more stretch gives a lot more launch height.

[mgardner]

Wow..thanks for all the good responses...lets see if I can give more info. When I stretch it back I usually take about 70 steps back. With 100 ft of rubber I realize I could probably stretch it more (about 100 steps), but at 70 there is a LOT of pull. I may try more stretch though to see what happens.

I'm launching a Condor with Fred Sage wings....I think its about 117 in span. composite wing, not the obeechi sheeted...7037 airfoil. This plane launches off a winch really well.

jrgospod...what strength monofilament did you use??

Thanks again for all the input

[Jack Hyde]

How far is 70 steps? You should be walking back about 250'-300'. If you can only walk back 150' before the initial pull is plenty, your histart is too stout. Try a winch launch pulling in only 150' . If its not into a stiff breeze the plane will only be half way up when you stop pulling. 100 steps will produce 50% more initial pull and 50% longer pull for twice the energy compared to 70 steps. That is huge.
I have launched planes just like yours with the rubber Mark Mech sells for 3m. It gets them up but it isn't like a winch.
The mono need to be strong enough to stand the initial pull just before release. That is the highest load with a histart. That will be something like 20lb test - too thin to work with. So you will want maybe 40lb.

[mgardner]

each of my steps is about 2.5 to 3 ft, so 70 steps would be about 200 ft...I may be under stretching it....but there sure is a lot of pull. The high start has a red rubber, guessing about 3/8 od tubing, but thats just a guess...

[averen]

Just to add some more info for everyone to chew on...

I was also flying with mgardner launching off of his hi start.

I have a 2 meter Spirit Elite which I launch with about 20% flaps. Another member of our group has a similar hi start which I can get a pretty decent zoom off of.

I'm not sure of the series that Mark has or of the other person in question. I know they are both the Pinnacle series from NESail.

I know Tim(other person with similar hi start) has selectable lengths of line on his hi start...I'm not sure what type of line he is using but I think it's the original stuff.

When Mark and I were flying I would take the hi start back a little further than he was but I was only getting mediocre launches compaired to what this hi start should deliver. I generally take Tim's back about 60 paces and I was pulling Marks back anywhere between 70-85 paces.

Good Luck with the Hi Start Mark :)

Averen (aka. Jared)

[aeajr]

Originally posted by mgardner
My question is, it seems like the flourescent line might be too long, as there just doesnt seem to be much energy left at the top of the launch...soooo, is there an optimum line length I should consider? I thought about cutting 100-150 ft of line off, and putting a swivel in so I can lengthen it back is desired, but not sure if this is a good idea...the swivel would probably just foul the line....

Another thought...my tow hook position is fixed, so I use the same tow hook position for both winch and high start. This is probably the reason that the plane is flirting with stall on the high start. I manage it with a tad of down elevator..

Thanks for feedback..

Mark

I read your post and I don't seem to get exactly what your concern is. When you hit the top of the launch, the rubber should be just about contracted, so there should not be much power left in it. Just enough to get some zoom, but not much more. That is a good thing, otherwise the hi-start will be pulling the plane down.

Are you concerned about the strength of your launches or the height of the launches. Taking line off will result in lower launches.

You could add another hole and blind nut to move your hook back. If you put the hook back you will get a steeper climb, but with a shorter line you will still get a lower launch.

Line length + tubing length plus applied energy is the primary determining factor on how high you can launch with a hi-start or a winch.

A max launch would occur if you could get the plane directly over the spike/turn around pulley at the end of the launch with the line straight up. That would be your max launch, ignoring zoom.

If you are not getting all the line off the ground, moving the hook back would give a steeper climb and might help you lift the rest of the line and tubing. But if you are lifting it all now, that is as high as you can go.

If you want a higher launch, you need MORE line, assuming you have enough power in the hi-start. I would think the hi-start you describe should have enough power.

An actual field test

My friend launches a 2 meter Spirit. He has he hook in the forward most position. There is a photo below of him launching the plane.

He was pulling his dynaflite hi-start way back trying to get more height. It has 100' of 5/16 tubing and 350' of line. He thought pulling back would get him higher. What we discovered is that he just needed more line. We made up add-on line in 50' lengths that we add using snap/swivels. He starts the day with the 350 foot of line. If he is hitting max height, he just keeps adding line till he runs out of pull room, or can't get the whole thing off the ground. If he can't pull it all up, he takes some line off.

He goes much higher now when he has a little wind.

My Spirit tow hook is in the most forward position, just in front of the CG. It is set for control rather than height. I launch straight out with neutral controls rather than up at an angle.

My hi-start is a Pinacle Standard, 100' of very strong half inch tubing and 400' of line. Due to the stronger rubber I get a more powerful launch with half the pull, compared to my friends hi-start.

In calm air with a strong pull my two meter Spirit can take up all the line and almost all the tubing. On a windy day I could probably add another 100' of line and still have room to get the needed pull.

Experiment, but you may just need more line. moving the hook back may help.

I hope what I have written here makes sense.

I am sure others will correct any mistakes I have made.

[fprintf]

Hi Mgardner,

I also have red tubing. Mine came from Hobby Lobby and I suspect is probably the same stuff. I get 30 paces, which is 60 steps with mine. Each pace is 6 feet, although they get shorter as the pull gets stronger toward the end of my walk. I don't think I get anywhere close to 250 - 350 feet of stretch - I am getting probably around 90 feet of stretch, same as what you are getting. Either I need to just hump on it and stretch the line some more or give it up and get a hosemonster from www.aerofoam.com.

Does anyone else have Hobby Lobby red? How far can you stretch it without entering the unsafe/close to snapping/reduction in overall life zone? Do I just need to wrap it around my waist and really hump it for another 100 feet? Will it get easier if I stretch it a bit more? In a breeze I get at least 500 foot launches. In no wind conditions I get 100 - 200 feet only.

[aeajr]

fprintf

You did not say what you were launching. 2 meter? 3 Meter?

I went to the hobby lobby site to see what you have.

This is your tubing specs. 3/16" ID with 1/16" wall thickness. Cross-section area is .0491 sq. inches. Color: Red, Weight: 2 pounds.

If you bought their ready made set-up then this is what you have:

These top quality outfits consist of: MFA’s 12" dia. Hi-Start reel with crank, 15" corkscrew anchor, Parachute, 240 feet of line, and our 100 foot pure latex Hi-Start tubing in three different sizes. These outfits have: A screw anchor that won’t pull out of the ground during your launch.

So, you have 100' of 5/16 OD tubing and 240' of line. You said you are pulling it about 180 feet (30X6'). Your launch off of this is probably 325-375 feet on a breezy day plus whatever zoom you can get out of it. Sounds like you get a big zoom!

This is the same dimmension rubber as my friend's Dynaflite, but he has 100 feet more line than you. ( see picture above)

You could probably pull it further when there is no wind. One of the guys at our field, when using my hi-start, does wrap it around his waist and pulls it much further back than I do to launch his 2 meter fiberglass plane. He calls my hi-start the bear!

Frankly I don't see that he gets much higher than I do from the basic launch, but he gets a better zoom off the end because the plane is moving faster and his tow hook is set further back then mine. When he comes over the top, he is really moving and the line is almost straight up. He is VERY experienced.

You could probably add 100 feet of line in a good breeze and you would get higher launches. Sounds like you already get a good zoom if you are hitting 500 feet.

[fprintf]

Sorry Aeajr, you were correct in adding the amount of line. I have 90 yds x 3 feet = 270 feet of line. I probably should add more line but I am also thinking I need to stretch it more since I am only getting 180 feet of stretch. I do get good zooms also but only when there is a stiff breeze. Also I am lifting a 38 ounce two meter with the hook in a very rearward position (I like it that way).

[aeajr]

Launch as usual. Note the angle of the line to the ground when you are at the top. Are you lifting all the line and the tubing? If you are, your stretch is fine. If not, try some more stretch.

Also, if you have a hook point that is a little further back, try that. It will be a little harder to control the launch, but it will give you a rounder arc, rather than the side of a triangle. This will get more power out of the stretch and help you lift the line for maximum height.

If you are lifting the line and the tubing, my suggestion is to try more line. 50' sections. Then launch as usual.

If you are getting the same angle between the line and the ground at the top, you are stretching it far enough for that wind condition. Add more line.

If the line and elastic are not fully off the ground when you are at the top, then try more stretch.

Stretch won't hurt, but it is line length that ultimately limits your launch.

I hope this isn't too confusing.

[Ricardo RW]

Hi guys,

Nice to hear that a lot of you use hi-start to put our babies in the air.

I wonder if any of you have had trouble with the rubber. Mine has several cuts and I have try a lot of things to join the pieces but none have work well.

How do you join split rubber? It would be nice to hear and see (photos welcome) how do you overcome this.

Regards.

Ricardo.

[averen]

guru_dick - I have heard of people cutting the rubber then inserting a piece of dowel inbetween the two halves. I don't have a hi start personally I've just heard of this done.

Good Luck!
Averen

[Ricardo RW]

Well, I tried with wooden dowels and with the original plastic ones that get loose. I put CA to secure the join but nothing, they slip away, maybe I'm pulling to much? Don't know. I do not put more than 13 lbs of tension because I ran out of the field.

Ricardo

[averen]

I wouldn't use CA around rubber or plastic...it can cause some undesireable results. You can always just tie a not where the break is...but I'm sure there is a much better way. Maybe insert the dowel and wrap that area with some thread to compress the rubber around the dowel for a tighter fit? Just a though.

Averen

[fprintf]

I would consider doing what people do at the ends of a histart. As averen as suggested, use wooden dowels. Make sure the dowels are a tight fit into the tubing. Then you can then use a glue like Houshold Goop after sticking the dowel in the tubing. For safety use fishing line or even dental floss very tightly wrapped around the joint to ensure no slippage.

Either that or buy some new connectors from www.aerofoam.com or some Hobby Lobby connectors.

[aeajr]

I have heard the dowel trick as well. I presume it has to be a very tight and pushed fairly deep into the rubber. When you pull the rubber it tightens around the dowel

You want the dowel to be rough, not smooth and you might want some rings cut into it so the rubber can grab better.

Many of the places that sell hi-start rubber have joining kits of some kind as well.

[Jack Hyde]

I put dowels in the ends of histarts using the method Fprintf described, goop up the dowel, slide it in, wrap with kite string. I did both ends of 3 histarts about 5 yrs ago and all are OK today. The rubber broke near the end of one but the dowel never came out. I was launching 3m planes with 2 of the histarts.

[patv]

I'm using 100 ft of hobby lobby red and 400 ft of mono line for my
histart. I stretch it to 100 paces or about 300 feet. I need to put some ribbons at 25 ft intervals along the rubber so I can see if it is getting lifted off the ground completely. I usually fly alone and am watching my plane rather than the rubber during launch but now I'm curious to see much of the tubing comes off the ground after reading this thread. I have been trying to estimate launch height ...this will be a simple way to measure it.
Pat

[aeajr]

Want to estimate launch height? Here is one way.

Put your plane up on its nose at the end of your hi-start, or you can work with a long tape measure.

Now walk away - if you have 100' of rubber, at the end of the rubber, turn around and hold up a stick. Hold it at arm's length and measure the wing on the stick. Mark it. That is what your plane looks like at 100'

Walk to the end of your hi-start. If it is 500', turn and measure the wing on the stick and mark it. That is what your plane looks like at 500'.

Right after you launch, compare the stick to the plane and you can estimate your height. It is not perfect, but it is close enough.

[Vince inTX.]

aeajr

You are on the right track but like you said, "Its not perfect but close enough". Well a bit closer but still not perfect would be to pull Pothageris out of our old math books and do some "cypherin and guzintaz". 500' histart stretched all the way out is 700' from the stake. So if you get a good launch and release 500' directly over the stake you will be aproximately 860' from the release point. So do some more walking before marking your stick and you will have a better idea where you are at release.

My 2 cents

Vince

[aeajr]

Agreed!

Mmmmm, hand not figured in the triangle. Good point! When I set this up, I was using it for overhead estimates. Thanks!

( square of the hyp.... dummy)

[Ricardo RW]

Originally posted by Vince inTX.
Pothageris

Isn't it Pithagoras..?

[aeajr]

Yea, that square of the hippopottomus guy.

[DeuceTrinal]

Pythagoreas.

[Ollie]

The square of the hippotomus hide is equal to the sum of the squares of the other two hides.

[aeajr]

Originally posted by Ollie
The square of the hippotomus hide is equal to the sum of the squares of the other two hides.

Ollie, I know that joke. It is the squaw of the hides.....

[Vince inTX.]

Originally posted by guru_dick
Isn't it Pithagoras..?


Yea well.......you get the point. :D If spelling is left out of the equation......then math is much easier. Thats why I always had trouble with algebra:(

crawling back under my rock now (easier to lurk from there)



Vince:D

[Ollie]

Here is how I terminate the ends of the histart rubber tubing.
1. Select a metal screw eye those outside diameter is a little larger than the inside diameter of the tubing.
2. Coat the threads of the screw eye with thick CA and allow it to harden. Apply additional CA until the thickness is built up to about twice the inside diameter of the tubing. When the blob of CA has hardened shape it with coarse sandpaper or a file into a teardrop with the round end of the teardrop at the end ot the threads.
3. Coat the shaft of the screweye with rubber cement, Goop or contact cement and force it into the inside of the rubber tubing untill just the eye is showing.
4. Wrap the outside of the tubing over the shaft tightly with a #64 rubber band or two.
5. Coat the rubber band wrapping with black silicone RTV to protect it from abrasion and UV.

The reason for using a rubber band wrapping rather than a dental floss or string wrapping is that the rubber band wrapping maintains compression on the tubing when the tubing is under high tension but doesn't over stress the tubing under storage. The outside diameter of the tubing shrinks and the string wrapping is loosened some when the tubing is under high tension. If the string wrapping is tight enough to compress the tubing enough it stress the rubber a lot during storage.

[the bone]

To Anyone out there.

When construting a high start, how far should the parachute be from the end of the line that hooks up to the plane. Also heard about swivels. How many are there and where do they go.

Thank You The Bone

[Vince inTX.]

0s<s------------------------------------s___________________________s\


That is a
"0" ring "s" swivel "<"parachute "s" swivel "---"string "s" swivel "___" rubber "s" swivel "\" stake.

The tow ring si ontop of the parachute. Theshroud lines at the top of the parachute run through the ring. That way the shroud lines transfer the launch load to the hi start not the parachute fabric. So the parachute is the end of the line tha hooks to the plane


Vince

[aeajr]

Vince has it right.

First, swivels are not required at all. You can just tie everything together. However I like to use snap swivels to join the parts.

Ring for attachment to plane hook. A key ring works.
This ties to the Parachute
Bottom of parachute can be tied to the line, but I like a snap swivel here so I can easily remove it.

A ring or a swivel at the start of the line.
Snap swivel at the far end of the line that attaches to a ring on the elastic tube. Again, so I can remove it.

Now I can change the length of the hi-start by replacing the line with a longer or shorter line. Or you can put another snap swivel/swivel combo somewhere mid line so you can remove some portion.

Let's say you have 50' of tubing
To that you add 150 feet of line.
Then you have another 50 feet of line that is removable
Maybe a second 50 feet of line that is removable
then the parachute.

You can adjust the hi-start from 150-250 feet of line depending on the plane and the wind conditions.

You could have ANOTHER 50 feet of tube that could be added depending on the size of the field.

It is all about how flexible you want to be in the sizing of the hi-start. No swivels are needed anywhere. Everything can be tied, with a ring for the plane and a ring where you put the spike in the ground.

[aeajr]

If you use snaps or swivels, I would recommend at least 50 pound rated pieces, and higher rating would be better. I use 100 pound rated hardware. If nothing else, they will be easier to handle.

[uabass]

mgardner,

I swapped the line out for monofilament. I get a lot less drag on the line when I launch. I now get a straighter line launch without the large bow in the line. I would highly recommend it. Make sure to get a colored monofilament line that you can see on the ground.

John

The line that came with my high-start breaks too easily :(
So what lbs. of colored monofilament fishing line should I get to launch my 2 meters?

Thanks,

[fprintf]

I use 60 pound test monofilament I bought from Wal-mart. I have yet to break it after 3 years of active flying/launching. Anything heavier and I think it'd just be adding weight, unlike on a winch.

[aeajr]

I use braided mason's line, #15 or #18 wichever is thinner. The line is bright pink and very easy to find in the grass. I believe it is 130 lb test.

Monofiliment is probably lighter but I find it hard to fin. I love the pink and use it on both of my hi-starts. Have not found the weight to be a problem.

[fprintf]

I think I figured out why my Histart chute drops so quickly when I add an extra 50 feet of #18 braided pink masons line that I bought at Home Depot. With the mono in a slight breeze the chute usually comes down slowly. With the braid added it comes down *much* quicker... I thought this was because of the braid being so heavy but the reality is probably that 50 feet of anything added between the mono, even more mono, will make the chute come down more quickly.

I dunno, I can usually find my chute fairly quickly but the pink line sure makes it that much easier!!!

[fly1milehi]

fprintf,
I would guess that the chute comes down faster with braided because the braided line has a LOT more drag on it than monofiliment will. I leave the masons line hanging over the concrete slab in the driveway LOL

it would be interesting to try a piece of each for comparison
Greg

[vbpflyer]

I think a good compromise might be one of the newer braided lines, which are much thinner, but have more tensile strength than Mason's and much more abrasion resistance than monofilament- they have kevlar in them. Something like Spyderwire maybe? Anyone have any first-hand experience or thoughts on this?
Brian

[averen]

Speaking of Kevlar...you can pickup kevlar twine pretty cheap...I don't know if anyone has tried it before but it might be a nifty little experiment.

Jared

[fly1milehi]

Vbpflyer asked about the newer braided filiment lines with kevlar etc., My experience with the kind used in stunt kite flying is that they are not worth it for high starts or winches. "Spectra" which is a name brand of kevlar kite string is essentially Kevlar tow filiments inside a braided 'sleeve' of dacron or other natural string fiber. Two reasons that Kevlar HAS to be wrapped is that it nearly impossible to tie together without the sleeve around it.. It just wont tighten and hold a knot. The other reason is that if the kevlar tow gets crossed by another line it pretty much melts instantly.

Hopefully someone else out there has more current filiment info than I do but thats way it was with Kevlar about 6 years ago.
Greg

[John Walter]

I picked up some bright orange braided dacron on eBay. I first loaded 100 yards of 200lb test dacron on my winch to reduce abrasion damage to the 400yds of 200lb test nylon mono.

Lots of zoom with less wear.

[fprintf]

Since it is a histart I do not see the need for a high strength/low stretch line, which is where kevlar would be helpful. There is really no need for a higher tech alternative on the histart in my opinion since I cannot yet break the line on my histart from tension. I suppose I can break it from abrasion but not from overly aggressive launching, since the rubber can only provide a finite amount of load.

I'll stick with mono -- cheap, easily found at Walmart, and very light. Now if the thread digresses to winch line then we can have a whole new conversation about what works because strength, stretch, zoom producing capability and abrasion resistance are all important and sometimes mutually exclusive.

[vbpflyer]

Fprintf,
My point was not so much that the line would be higher strength, but that the same strength could be achieved with a much smaller diameter line ( i.e. less drag). As far as being able to tie knots in it, it's designed for fishing so I don't think that will be a problem.
I see your point about stretch, or the lack thereof, being a consideration.
Thanks,
Brian

[aeajr]

When I got my NESAil hi-start it had 400 feet of bright pink masons line on it. Launches great. never had a problem and if it does need to be replaced, $3

They all work

[histarter]

NSP has a heavy duty rubber that is out of this world for low stack tension. At 15 lbs tension (1/2 inch red tubbing) was all that I could handle to toss my Ellipse. In calm, it worked well, but was never competitive to a winch (a sport winch at that) and I simply accepted its limitations.

It did build my right arm up to the point it looked like Arnold's arm (i.e. the Governor of Caif.).

[aeajr]

The NEsail hi-start that has the 1/2 inch rubber, The NESAil Pinnacle XL, is intended for 4 meter planes. However I launch my 3M Legend with it at about 24 pounds pull. Takes it right up. I have 100 feet of rubber and 500 feet of line. If there is a bit of a breeze, it launches right up there with the winch launches, less the big zoom. Small Zoom!

A more appropriate hi-start for a 3M plane would have about 3/8 rubber NESail Pinnacle Large. The 1/2 is too strong so the pull can't be full length. But I get it WAY back there for the Legend.

I launch may 2M spirit on it at about 12 pounds/150 foot pull. That is all I can hold on that plane and about all I would want the wing to take. Goes up like a rocket, 500 feet of line and all. With a little breeze it takes all the line.

Definately not my first choice for a 2M plane. - NESail Pinnacle Standard is what I would use for a 2M plane.