Learning to use a hi-start

[aeajr]

I am making this post because I could not find tips or advice anywhere on the internet on how
a person, working alone, could learn to use a hi-start. I invite more
experienced sailplane pilots to add their tips, comments and advice to mine.

Hi-start launching.

First, let's be clear, I am NOT talking about competition launches here I am
talking about safe sport launches. I am sure someone will post about maximum
altitude and such. I just want to help you get in the air safely.

Second, get a coach/instructor if one is available and ignore all of this.
This is ONLY intended for someone who is unable to get help.

Third, your plane must already be well trimmed and flying straight and even
from a hand launch. Fail to this and the hi-start will turn your plane to
junk!

Fourth and very important, make sure your tow hook is in the forward most hole
that your plane has. It should be a little in front of the CG of your plane.
This will give you a more controlled launch than the more rear, competition
positions.

OK? We understand the goal here? Safe and gradual build up. Control, not
height!


Always launch into the wind. Launching is easier with a mild breeze than it
is in dead calm air. For learning purposes I would say you want at least 2-3
MPH and no more than 6-7 MPH of head wind.

I was taught to launch with all controls at neutral. In fact my initial
launches were with a little down elevator to help reduce the chance of a
pop-off. But I started with a full size hi-start and an instructor who made
the first 4-5 launches for me so I could watch and he could see how the plane
would behave. Then he released the plane on the next three while I held the
radio to control the plane. Then I released while he flew the plane. Then I
did both. But we were working with the BIG hi-start in a huge field and he
was there to guide me. If your plane is properly trimmed, all controls should
be at neutral for your launches.

You should only need rudder to control the launch. You may use a little up
elevator at the very very end to help release the ring from the tow hook, but
mostly I just let it fly off. If you get your angle off a little left or
right the plane will tend to go that way, just like a bad hand throw. Use the
rudder to get it back to center.

Build up to it slowly. Think of a hi-start as an assisted hand throw. Do
exactly what you would do on a hand throw. Basically flat firm throw.

I don't know what hi-start you have or how big it is, but if it is a "full
size" hi-start it probably has 30 meters/100 feet of elastic and 100-120
meters/300-400 feet of line. That is an awful big thing to handle on initial
launches without a coach.

You can either get an up-start which is 5-15 meters/15-50' feet of elastic
plus 15-50 meters/50-150 feet of line which can be used in a smaller space
and, in my opinion be a little less scary. Or, take your big hi-start,
replace the big length of line with a smalle length. You can cut a 50-100
foot length to use for your initial launches You can reattach it later with
snap swivels or just tie a knot.

Get a metal ring, 1.5-3 inches, that will allow you to loop the elastic onto
the ring in some fashion to secure it so that you are only using part of the
elastic you have to make the shorter launcher. Make sure the stake that you
put into the ground has a washer on it that will not pull through the ring.
Don't cut the elastic.

If you start small, say 10' of elastic and 30' of line it will be a lot easier
to control, and the launch will be lower and the energy smaller. Again, just
an assisted hand throw. We will use this length combination for this
discussion.

Pull back 5-10 feet, or about 1/2 the length of the elastic, for the first
launch.

Check to make sure all of your controls are working.

Stand firm and just give it a straight. firm, flat throw, controls at neutral.
You should only need rudder to control direction.

It should go out just like a hand launch, only with a little more speed and it
should naturally climb a little. It should just fly off the end of the line.
Don't go for height, go for control.

Build up the strength of the pull over several launches. 1/2 the length of
the elastic. Then 3/4, then the full length. Then 1.5 times the length of
the elastic. Build till you are comfortable. Then just slide the metal ring
further down the elastic and add more line. Use roughly 1 foot of elastic to
3-5 feet of line.

As the pull gets stronger, the plane will fly out faster and the lift of the
wings will take it higher naturally. No need to throw it up, it will go up on
its own. You can reserve aggressive angles and the more rear tow hook
positions for competition.

I have about 60 launches with my Spirit 2 meter. I launch flat with neutral
controls and the forward tow hook position. Using my smaller launcher (25'
tubing and 100' line) I get 100-150 foot launches depending on the wind.
With the larger one (100' elastic and 400' line) I estimate I go up 400-550
feet and can zoom off of the end if I want.

Like you I was afraid of the hi-start. If you had someone to coach you through the first few you would be fine. If you don't, try this method.

That plane was made to fly. Fly it!

[sierra-gold]

aeajr stressed it, and I will restress that the sailplane needs to be well trimmed out before using a hi-start. The speed attained in launching from a hi-start will amplify the effect of any warps in the flying surfaces. This can make for very exciting launches, especially for a beginner. If at all possible, have your new sailplane checked out by an experienced pilot before attempting a solo hi-start launch.

Secondly, ALWAYS wiggle your sticks just before letting go of a sailplane on a hi-start. I use my nose or teeth to bump the right stick to insure all is operational. There is nothing more sickening then to realize you have just launched a "dead" sailplane. Unlike a winch, with a hi-start there is no pedal to take your foot off of. The hi-start will drag your sailplane down the field throwing off parts as it re-kits your creation.
Don't ask me how I know! :(

Sierra Gold

[rdeis]

On the controls:

1> Down elevator is your safety net:

If the plane gets squirrily on launch, a little down stick will bring it back in line. Too much down and you fly off the line-- frustrating, but safe. If it's really squirrily, odds are you're headed for tip-stall or pop-off, both of which can destroy the airplane.

2> Be aggressive with the rudder, and stay ahead of the curve:

If you throw off center, the plane (if left to it's own devices) will trace a beautiful semi-circle curving off in the direction you canted it until it slams nose-first into the ground. You prevent this by putting the rudder HARD-OVER to bring it straight back up the line. Beware, however, that you will almost certainly overcorrect the first few times, so be ready to send it hard over the other way. Again, a little down here will give you more rudder authority and help settle things down.

3> Elevator is *NOT* the key to more height, don't use it that way.

Up elevator on the high-start stresses your stab, creates drag, and increases the likelyhood of tip-stalling or popping off. This is especially true at the beginning of the launch. Don't do that. When you're ready for more aggressive launches, you'll get height by moving the hook and stretching the line.

4> If you pop-off, be aggressive on the elevator:

Popping off the hi-start is exciting- you're about to stall and tail-slide the airplane at low altitude. To recover, give it full elevator immediately when you hear it pop, and be ready to fly it out of the stall. That usually means full down and gritting your teeth while the airplane dives waaaay to low gaining enough airspeed to level out.

[aeajr]

The voice of experience is helpful to new pillots, especially when we all agree. Thank you for adding your comments.

New Pilots who read these posts, please feel free to add your questions. We are here to help you.

[BMatthews]

One of the biggest mistakes I see in pilots of all skill levels is not properley THROWING the model during any launch be it with a high start or a winch.

At higher tensions a level release will let the model speed up very fast and rotate to a nose up attitude very aggresively. This in itself can lead to a pop off. For this reason I like to launch my models with the nose up at a 45 degree or so angle.

But to do this safely you MUST assume the stance of an Olympic javelin competitor and THROW the model just like that javelin. You may get away with it for a while using the lighter poly ships but if the wind is a little wrong one day or you buy some new super ship and try to use the limp wrist launch it's going to stall and snap into the deck. When the line is under tension it creates a very high virtual wing loading and that is what let's your model glide "uphill". Take that high virtual wingloading for granted and it'll stall and snap in an eyeblink.

Find some pics of guys like Joe Wurts and others launching their models. Their feet are along the line of the launch and space well out. Seeing a shot of them with their model just out of their hands and you'll see the ending of a powerful throw and proper follow through.

I know it's hard to think and do a javelin throw with all that tension pulling at the model but it's important that you develop the right method now before it costs you your first molded ship.

[culiv]

Thanks for the information. Never launched a sailplane with anything other than an electric motor. That will be changing as soon as I get my 1-26 hlg covered.

I've been planning on using a high (or maybe lower) start to get that heavy beast in the air so that I won't have to be heaving away every minute or two. Had no idea there was anything other than hooking on and turning loose of it.

Have never flown in the area where I now live. I've watched the buzzards though, and there seems to be pretty good lift much of the day. Looking forward to getting some airtime. Bet I'll be more successful now.

[aeajr]

I am not familir with your plane.

The type and strength of the hi-start you use is determined by the weight of the plane and the wing span of your plane. A two meter ship can be launched with 3/16 to 5/16 tubing. A three meter would most likely require 6/16 to 7/16 to reliably get off the ground. 8/16 or more would probably be recommended beyond that. These are all outer dimager measurements ans assume a 1/16" wall. So a 3/16 ID plus two 1/16" walls equal 5/16" OD.

In some cases they rate the tubing by ID and thickness of wall.

My hi-start is 8/16 or 1/2" AND has a 3/32" wall as opposed to the usual 2/32" wall. It is rated for 3 meter and up but I use it to lanunch a 2 meter plane. I just pull it back less than the big planes do.

Be sure you are using the right hi-star/up start.

This might be helpful to read this:
http://www.aerofoam.com/hosemonster.html

My advice is, when in doubt, go up a size. You can always pull it less. But if your hi-start is not strong enough your launches will be weak. You may only be able to launch with a 5 MPH or higher breeze.

My friend tried to launch his 2 meter Spirit with 1/8" bungee cord. It was totally inadequate to the job in quiet air and just barely put the plane up with a 5 MPH breeze.

I launch the same plane with a 1/2" hi-start and get great launches. I just don't pull it back very far.

If I had a 5/16 OD based hi-start I would be pulled back further. It would give a "softer" launch because the tubing pulls back over a longer time/distance giving a less sudden acceloration. Many people prefer this kind of launch. It is easier on the plane but requires more room to pull the hi-start.

All points for your consideration. Go up a size when in doubt.

[aeajr]

If this is a very heavy plane, and impractical to throw, I have seen people winch launch 18 pound scale gliders using a little wheeled cart. They hook a harness to attachment points on either side of the cabin.

I don't see any reason why you could not do the same thing with a hi-start, but you would be talking a VERY strong hi-start for an 18 lb plane.

http://www.nesail.com/pinnacle.html
The NE Sailplanes Pinnacle XL might do the job for that large of a plane.

What are the specs for your plane?

Can you hand throw it?

[culiv]

aeajr, If your questions are directed at me, I'll be flying a DAW Schweizer 1-26 HLG. It's EPP and 59 inch span. Weight should be in the 20 oz range with a wing loading of about 6.75 oz. per sq/ft. It is'nt that heavy, just a lot heavier wingloading than built up stuff (vs. 3.5 oz or less on the Skybench Lil Bird 2).

I know that this plane isn't a likely candidate for extended flights with just a hand toss. I plan on getting one of Skybench's Mini Hi Starts. It'll save the arm and back. I know that a larger set up might be better with the weight of the plane, but this one will be better than me throwing it and will still be usable in the areas that I will be frequenting.

[shaneyee]

How high do you get in a high start launch? And how long is the flight after that in thermal-less conditions? I have 25ft of 3/8" surgical tubing from my Control Line combat days ( use them as fuel tanks - they really stretch! ) ...if I combine them with 50-60ft of line...how high can I launch a 40oz 72" glider?

Thanks

Shane

[Peter Young]

As a new glider pilot this is very helpful - many thanks for the advice. I recently bought a little 1.2m hand launch plane and fitted a tow hook. A few weeks back I went to the local park with a short field high start and learnt through a couple of terrible near misses how to get the plane up safely.

My first attempt involved releasing the plane at a 60 degree nose up orientation - the poor thing squirmed side to side and I almost lost it wing first into the ground. After repeating this mistake I realised I needed to get the nose down more in launch. This resulted in much safer launches, but I was also using ailerons rather than rudder to steer her up, and holding up elevator to try to gain maximum height. I guess these are instinctive controls to make, so I'm very glad to get this advice from you folks.

Hopefully you have saved me a smashed plane (at least at launch - still plenty to go wrong). I'd also be interested to know how long I should expect to get in dead air conditions - seems like the plane comes down very quickly.

Peter

[aeajr]

Originally posted by culiv
aeajr, If your questions are directed at me, I'll be flying a DAW Schweizer 1-26 HLG. It's EPP and 59 inch span. Weight should be in the 20 oz range with a wing loading of about 6.75 oz. per sq/ft. It is'nt that heavy, just a lot heavier wingloading than built up stuff (vs. 3.5 oz or less on the Skybench Lil Bird 2).




This is a pure guess, but I would think 1/8-3/16" od tubing should send it up nicely. Is there a tow hook of some kind on it where you can connect the hi-start? If not, you will have to add one and reinforce that location to spread out the pull.

If you want to use a smaller unit, you might uses one of these up-starts as reference examples.

http://www2.towerhobbies.com/cgi-bin/wti0095p?FVPROFIL=++&FVSEARCH=up-start&FVPROFIL=++

My friend is launching his Spirit 2 meter with a Dynaflite HD hi-start. The Spirit has built up wings and balsa fuse. It weighs about 30 oz I think. We had it out over the weekend and using 5/16 tubing on his dynaflite hi-start he was getting nice gentle launches to good height. I think he has the HD.

http://www2.towerhobbies.com/cgi-bin/WTI0095P?FVSEARCH=hi-start&FVPROFIL=++&search3=Go

[aeajr]

Originally posted by shaneyee
How high do you get in a high start launch? And how long is the flight after that in thermal-less conditions? I have 25ft of 3/8" surgical tubing from my Control Line combat days ( use them as fuel tanks - they really stretch! ) ...if I combine them with 50-60ft of line...how high can I launch a 40oz 72" glider?

Thanks

Shane

Height is a function of line length, wind conditions and properly matching the power of the hi-start to the plane.

If you have 100' of elastic and 400' of line, you can reach 400-550' on your launch. A little breeze actually makes for higher launchs as you get a kite effect on the plane.

I would say your 3/8" tubing should be plenty strong for your 40 oz plane. It should be able to handle 100 feet of line and perhaps more.

My practice up-start has 7/16" tubing which is really a little strong for my 2 meter 30 oz spirit. When wind conditions are light, I only use 100' line. If there is a 5mph breeze or more I add 50' of line. With that combo and a little zoom at the end I estimate I am getting 200+ foot launches.

How long can you stay in the air? That is a pilot talent issue combined with the plane and the current air conditions. 2-4 minutes might be a good range on a no lift flight from a 500 foot launch with a lightly loaded plane and a competent pilot.

[aeajr]

One of the things I do, especially with my up-start is I have part of the line removable. 25' of tubing + 100 feet of line works fine. If there is a nice breeze, sometimes I can add another 50' of line. I have it set up with fishing snap swivels to make it quick and easy.

If you have a larger hi-start but don't have enough room to pull it far enough, remove some line, as I did above, then add it back when you have the room.

[BrianRickman]

Thank you all for sharing your tips. I'm sure reading this and a couple other threads have saved me from crashing my glider.

> If you throw off center, the plane (if left to it's own devices) will trace a beautiful semi-circle curving off in the direction you canted it until it slams nose-first into the ground.

Throwing on center is not as easy as it sounds, at least for me. So far out of 8 high-start launches with my Spirit I think 6 have started out with the plane making a sharp turn to the left. On the other two launches it went almost straight up after I released it. Haven't crashed yet as the rudder is quite effective in getting the nose pointed in the right direction, but is is disconcerting and the plane wastes a lot of energy going sideways that could be used for going up instead. I figure I loose 100' of altitude on the curved launches vs the straight ones.

I think I just need to practice more at throwing the plane straight ahead with the wings level. I can do that with no trouble for hand-launch glide tests, but doing it with the highstart pulling on the hook is a whole new ball game. Maybe I need to start lifting weights or something :).

[aeajr]

Brian,

You are right, it can be challenging to get the plane level. Using the gradual method I covered above, I hoped that the slow build up of tension would help people get that part right, but I still go off level at times.

A second issue is that people let the hi-start pull the plane out of their hands. If there is a good breeze, this works, but if there is not, the plane stalls before it gets up to speed and will usually drop off to one side or the other.

Hopefully it reaches speed BEFORE it hits the gound. Is it possible that you are not giving the plane enough of a push/throw when you are launching and that it is stalling on you?

[aeajr]

While this thread is about hi-starts, winchs are the next logical progression. I have been trying to master a winch launch. I am part of a sailplane club and we have 4 winches. The club contests are all based on winch launches so I have to learn to do this if I am going to enter the contests.

Weeeeellllllllll, I had two sorta ok launches one day. So I was feeling that I had the hang of it. The next time I went out, I approached the winch with confidence. MISTAKE.

I don't think I threw the plane hard enough and it stalled before it got up to speed. Splat on the left wing.

[aeajr]

This is the left wing, after I removed the covering. I think I can rebuild it, but it will take some work.

[BrianRickman]

Originally posted by aeajr
Is it possible that you are not giving the plane enough of a push/throw when you are launching and that it is stalling on you?

It's possible. I was having trouble holding on to the plane with the full tension of the hi-start pulling on it. Next time I go out I'll try stretching it a bit less. Maybe I'll get more altitude by keeping the tension low enough that I can throw the plane more effectively.

[Ollie]

Brian,

You should stick to planes with wing loadings of under eight ounces per square foot and use mandrel formed rubber for the histart. The mandrel formed rubber will stretch more and store more energy with less tension than extruded surgical tubing. The combination of a good rubber and light wing loading will allow you to get full height launches with less tension and less strain throwing the model properly. Such a model will accelerate to flying speed quicker because its stalling speed will be lower. If the tow hook isn't too far back it won't veer on launch. You can get mandrel formed rubber from Aerofoam.

The model that starts to veer on launch should be given a touch of down elevator and the down held to get the plane out of a stall during launch.

[BrianRickman]

Thanks for the tips Ollie. I'm going to try to live with my current plane and highstart until the winter "building season" arrives, which I suspect will be within the next month or so. I may have a lighter glider and/or better highstart next year. Having said that, I know at least part of the problem is my technique since I have had two really good straight launches out of ten so far.

I have been using down elevator along with rudder to get it under control when it veers off to the side. Definitely helps to prevent pop-offs during the high-g turn.

[aeajr]

Ollie brings up one very good point. Your tow hook should be in the most forward hole. My spirit came from the factory with the hook in the middle hole. I had to open the front hole.

The more foreward position will give you excellent launches with the greatest stability. As you go further back, the launchs may get higher, but the launch gets less stable.

Frankly, with the hook all the way up front I am launching about as high as my hi-start will go and get a good zoom off the end.

[BrianRickman]

My tow hook is in the middle hole as that is where it was when I got the plane (used). I will try moving it up front before flying it again.

[aeajr]

You will find the front position much easier to control.

[aeajr]

Originally posted by BrianRickman
My tow hook is in the middle hole as that is where it was when I got the plane (used). I will try moving it up front before flying it again.

Have you had a chance to try the front setting? I am dying to hear your results.

[BrianRickman]

Not yet. I'm going to try again this Saturday if the weather is decent. It snowed today :(.

[BrianRickman]

Flew the Spirit again today. The forward towhook was a big help. Did two good winch launches, one with a more experienced pilot on the pedal, and one on my own. The winch really gets it high! I even caught a little lift. Didn't climb much, but I was able to stay up longer then usual. Later there was a mechanical problem with the winch so it was packed up and I used my hi-start for a while. Got in three nice launches with that as well. Then it happened...

On my fourth and final launch something went terribly wrong. I think maybe there was a strong gust of wind from the side, or maybe I just dumb-thumbed it, not really sure. Anyway, it got up about 15 feet and then fliped over so the nose was pointing down. I tried to save it but just couldn't turn it over fast enough. There was a loud bang and a shower of balsa wood. The wing was a total loss. The rubber bands cut through the center section, and the tips shattered. Amazingly enough, the fuse and tail look fine. Would not have believed that was possible with a balsa plane. I have not tested the radio gear yet, though I'm hoping it all survived as well.

I ordered a "Gentle Foamy" a couple days ago, just in case something like this was to happen, so I'll be back in the air again soon.

Maybe after I've flown the foamy for a while I'll build a new wing for the Spirit. Or maybe not. I only paid $35 for this one, and it came with two standard servos. I think I got $35 worth of value from it as I have found out that I really enjoy flying sailplanes.

[aeajr]

Sorry to hear of your loss. I to smashed up my Spirit, but I did it on a bad winch launch.

How did you get a side gust. You are supposed to be launching into the wind!

One of the things I like about the hi-start is that I can move around as the wind moves. so, if it moves off to my right a little bit, I just walk left with the plane hooked up until the ribbon on my radio antena is straight.

Here are a few ideas.

I hope you gathered up everything at the field. I thought my wings were totaled as well. Two weeks later I put them on the table and stripped off the covering. They were no where near as bad as I thought. I am fixing them now

Watch e-bay for low priced spirit kits or ARF sailplanes.

This link goes to an ARF Cirrus which is almost a clone of a spirit. Currently it is going for $38. It will probably go final at abround $55.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3151142210&category=2563&rd=1

At tower Hobbies, a spirit kit $47, a wing set is $60 and a Spirit ARF is $95. A spirit RTF, including the radio, receiver and servos is $139 RTF. I got a kit on e-bay for $20+10 shipping. I am using the plans from that to help me fix the one I have been flying.

My launches off the hi-start are as high as the winch, so my only reason to go to the winch is to enter competitions where the winch is required.

Now, tell me more about this foamie. Can you hi-start launch it????

[BrianRickman]

The wind was quite variable. All of my successful launches were into the wind. Guess I just wasn't paying enough attention on that last launch.

Here's a link to the home page for the foamy:
http://www.isthmusmodels.com/mtntoy/gentle.html
It's supposed to be OK to winch launch it.

My hi-start is a bungie type, so it only takes the plane 1/2 as high as the winch, but it's still plenty high enough for sport flying.

I saved the fuse, but left the wing parts in the trash. Just didn't seem like it would be worth the trouble to fix it. I'll keep an eye out for Spirit kits on e-bay for when I feel ready to rebuild it.

[aeajr]

BrianRickman

You don't mention the size or length of the bungee elastic, but I know that a 5/16 Dynaflite heavy Duty hi-start with 100' of elastic and 350' of line gives a great launch to a two meter Spirit. It will will take the plane up very high with a gentle launch. www.towerhobbies.com $60

If you plan to move on to larger sailplanes some day, you might select the NE Sailplanes Standard hi-start. Mine has 1/2" rubber and will take a 3 meter plane up to full height. My Spirit goes up very agressively, nothing soft about the launch. Since I don't pull it back as far as I would on the Dynaflite, I don't need as much room. If there is a breeze I could probably add another 50-100 feet taking it to 500' of line + 100' of tubing.

Just some thoughts. If you are commited to and have full access to a winch, then you probably don't care about hi-start alternatives.

[BrianRickman]

My bungie hi-start has 100' of 3/16" bungie cord and about 200' of line. It's Hobby-Lobby's Standard Bungee Launch:
http://www.hobby-lobby.com/histart.htm .

Eventually I will get a better hi-start, but this one is good enough for now. The club winch is available most weekend mornings, which is when the field is more popular, and I have free access to it at those times.

My eventual goal is to fly a DAW Ka6E (117" span, 85 ounce weight): http://www.davesaircraftworks.com/giant.htm#ka6e
I don't think I'm strong enough to use a hi-start that would pull that one up so I need to learn to use the winch eventually. However, as yesterday's Spirit crash indicated, it's going to be a while before I'm ready to fly that plane.

[Ollie]

Brian,

The tow hooks on the Ka6E should be mounted on the fuselage sides, close under the wing to avoid violent pitch up. A bridle is needed and should run loosely through the normal launch ring.

[BrianRickman]

Thanks Ollie. I think I understand what you are describing. There would be one hook on each side of the fuselage, and a short line with a ring on each end and some kind of attachment point in the center for the winch. Is that right?

[Ollie]

The short line with the rings at each end has to be able to slide through the ring that is attached to the end of the winch line. if you don't let the yoke line slide through the winch line ring, you could run into yaw induced roll during the launch and a yaw-roll oscillation could develop. If you tie the yoke line to the winch line or ring, then if the model yaws during launch, the tow hook on one side of the fuselage will be pulled harder than the other and the plane will yaw. The yaw will be converted into undesired roll by the dihedral. If the yoke line slides through the winch line ring, then your rudder will be fully in control of yaw during launch.

[BrianRickman]

I understand now. Sounds like a good solution. I'll keep that in mind for when I eventually get a Ka6E, though it might not be until next year. I want to be very comfortable launching a 2M R/E sailplane before moving on to a 3M A/R/E scale sailplane, even if it is made from EPP.

[aeajr]

Originally posted by BrianRickman
My bungie hi-start has 100' of 3/16" bungie cord and about 200' of line. It's Hobby-Lobby's Standard Bungee Launch:
http://www.hobby-lobby.com/histart.htm .


My eventual goal is to fly a DAW Ka6E (117" span, 85 ounce weight): http://www.davesaircraftworks.com/giant.htm#ka6e
I don't think I'm strong enough to use a hi-start that would pull that one up so I need to learn to use the winch eventually. However, as yesterday's Spirit crash indicated, it's going to be a while before I'm ready to fly that plane.

One of the guys in our club uses 3/8 bugee to launch his spirit. It has a very explosive delivery of power, much more so than my 1/2" tubing hi-start. It puts his Spirit up, but I find it very abrupt, almost startling.

That is a very cool looking sailplane. I had never seen anything like that in foam. I have bookmarked it.

As for being strong enough to launch the 117" plane, I guess using the winch, you will have to put it on a trolly and pull it off the ground. I have seen that done with a winch. I have never seen it done with a hi-start althought I guess it could be done.

Good luck to both of our Spirits!

[aeajr]

Originally posted by BrianRickman
I understand now. Sounds like a good solution. I'll keep that in mind for when I eventually get a Ka6E, though it might not be until next year. I want to be very comfortable launching a 2M R/E sailplane before moving on to a 3M A/R/E scale sailplane, even if it is made from EPP.

Brian,

May I suggest, as a fellow Spirit pilot, that you add the spoilers to your spirit. It is not hard to do. The instructions show how to do it with one servo in the the fuselage and string running through the wings.

I did it by putting servos in the wings, but it doesn't really matter how you do it. Learning to use the spoilers is another growth step you can take with the Spirit on the way to your 3 meter plane.

I was amazed at how much the spoilers help with the landing. You can land much more smoothly and in much shorter distances with the help of the spoilers. I found this especially helpful in gusty wind conditions.

I spent one day launching and landing in 15-20 MPH winds solely for the practice in wind. On the first day I did it without spoilers. On the second I used the spoilers. What a difference.

As you progress with your 2 meter plane, add spoilers. You will be very happy you did.

[BrianRickman]

Yes indeed. I hope your Spirit soars again soon.

I've found that if I stretch my hi-start fully (about 150') it is very hard to handle. Pulls the plane out of my hand before I have a chance to throw it properly. However, if I limit the stretch to 100' or so, it is much easier to work with and still gives a decent launch. Of course, it works better with a bit of wind then in absolute calm conditions.

For launching a big glider, I'm not so much concerned about throwing it hard enough, as I am about holding it over my head with 20+ pounds of force from the hi-start pulling it forward. I have successfully hand launched a 5 pound powered plane (big-t). Was not as easy as with a smaller plane, but not too difficult.

[aeajr]

Are you saying you have a bungee hi-start that has 100' of bungee and you stretch it back 150'? No wonder you can't hold it. That must be putting 20+ pounds of force on a 2 pound plane. That would probably be enough to launch that big sailplane.

How do you keep from crushing the fuse holding the plane? I am 6/2" and I am not sure I could hold that.

I can see why you have had trouble controling the launches. The recommended pull on the Spirit is about 8-10 pounds. I think you are over pulling that bungee. You would pull 5/16 surgical that far, and perhaps even further, but not bungee.

Having used my friends 3/8 bungee launcher I don't think we ever pulled it more than 50% of its length and had a hard time holding the plane at that. Of course his is stronger than yours, but still.

I am not being critical, I am just giving you food for thought. Try a shorter pull. With your recently improved techniques you may find your launches are just as high with less stress on you and the plane.

[BrianRickman]

That is what I was saying. I may be over estimating the distance I'm pulling it. I'm not sure exactly how long the field is.

When I stretch it a shorter distance, which I am estimating at 100', it works much better then when I stretch it to the limit. I did notice that the winch launches seemed gentler then the hi-start launches, even with the reduced stretch. When I have another glider to play with, I'll experiment a bit more with varying the amount of stretch. Probably should get a fish scale so I can get a more accurate picture of how much pull I'm getting. Seems like there's always one more tool that I need :).

[aeajr]

Yep! Always some new gadget.

I love this hobby! Don't you?

[aeajr]

Originally posted by BrianRickman

On my fourth and final launch something went terribly wrong. I think maybe there was a strong gust of wind from the side, or maybe I just dumb-thumbed it, not really sure. Anyway, it got up about 15 feet and then fliped over so the nose was pointing down. I tried to save it but just couldn't turn it over fast enough. There was a loud bang and a shower of balsa wood. The wing was a total loss. The rubber bands cut through the center section, and the tips shattered. Amazingly enough, the fuse and tail look fine. Would not have believed that was possible with a balsa plane. I have not tested the radio gear yet, though I'm hoping it all survived as well.

I ordered a "Gentle Foamy" a couple days ago, just in case something like this was to happen, so I'll be back in the air again soon.

Maybe after I've flown the foamy for a while I'll build a new wing for the Spirit. Or maybe not. I only paid $35 for this one, and it came with two standard servos. I think I got $35 worth of value from it as I have found out that I really enjoy flying sailplanes.

BrianRickman

Did you ever get your Spirit back in the air?

As you will recall I crashed mine a few weeks before yours. I just finished rebuilding mine and am waiting for good weather to fly it.

How about that Gentle Foamy. I am very interested in your experience with that plane. Thinking I might get one.

[BrianRickman]

aeajr,

I still have the fuse from the Spirit, but the wing was damaged beyond the level at which I am willing to make repairs. I may build a new wing for it some day...

The Gentle Foamy is great. I think we've exchanged emails about it already, but just in case that was someone else... It launches very easily on a 2 meter hi-start or a winch. It has a very strong wing so full pedal winch launches are fine, though certainly not necessary. It flies slowly with a bit of up elevator trim. Lands easily. Flying it is generally easier then the Spirit, though it doesn't stay up quite as long. My AUW was 35 ounces with a 1400 Mah nicad pack, two standard servos, a Hitec 555 receiver, and 2 ounces of lead in the nose.

A couple weeks ago I decided to try it with a motor so it now has an Atomic Force geared 3.8:1 with a 12x8 folding prop on the nose, and a 6 cell CBP 1800 Mah Nimh pack under the wing. AUW is now 45 ounces. I have not flown it in this configuration yet, but I'm hoping to try it out this weekend if it stops snowing long enough.

[aeajr]

sounds good.

Yes you and I did exchange e-mail a while ago. I had forgotten.

I had not heard of anyone launhcing the Foamy from a winch. Full Pedal? That is impressive.

[BrianRickman]

You can hear the winch motor strain as it gets near the top of the arc :).

The wing is built from three pannels (flat center section with poly tips). The wings have hard-wood spars top and bottom, a balsa trailing edge, and plywood joiners for the tips. It's very strong.

[webguyjv]

This thread is really great guys -- great work!

I want to start uising a hi-start. I have one that's about 12 year sold - heven't used it in a LONG time. The surgical tubing is brittle and it needs to be completely replaced.

Do you guys know of a place in Northern California that sells the kind of tubing used on hi-starts?

I'm wondering if it's cheaper to replace the tubing, or just buy a new hi-start.

Thanks again for this great thread.

Happy Flying ;-)

Webguyjv

[aeajr]

Webguyjv,

Glad you like our little discussion here.

Whether it is better to replace the tubing or the whole thing is up to you. If the line is good, the parachute good, the rings good, the reel good and the spikes good, then all you need is the tubing. on the other hand the difference in price for a complete unit vs just tubing may not be that much.

For example, the Dynaflight HD at Tower is $60. The tubing alone is $50. For $10 you get the spool, ($5) parachute ($12) rings ($3), line ($3) and a spike. - might as well get the whole kit and use the old stuff to make a shorter up-stat for practice.

What kind of plane are you launching and what size and strength was your old hi-start. Were you happy with it.

Maybe we can point you to a good source. The interenet places ship pretty quickly.

My upstart is made with 25 feet of REAL surgical tubing that I bought on e-bay for about $12 I think.

Tell us how we can help you.

[fprintf]

http://www.aerofoam.com/hosemonster.html is the only place to buy histarts, imho.

Buy cheap, buy twice.

In this case it is not that much more expensive to get the really good stuff. $55 plus shipping for 100 feet of the best histart rubber there is. $110 including shipping for a complete 100' histart, including nylon line, a nice parachute, proper connecting rings etc.

Unfortunately Mark in is Washington State, so not local. There are two ways to do it locally. 1) go to your local hobby shop and pick up a histart - usually $60 - $70 complete. 2) Go to your local medical supply shop and purchase surgical tubing. I would bet that in Northern CA with any consistent use (e.g. every weekend) it would only last a year or so due to UV exposure.

I like my Hobby Lobby Hi-start, but next time I am definitely going for an Aerofoam Hosemonster. I have been flying off of one and the rubber is *so* much more stretchy, and feels just as powerful but somehow softer.

[gdjsky01]

Then the inevitable happens. And now you have two fine peices of latex rubber tubing. What's the best way to join them back together? Welded steel rings? Key rings? Just knot them together?


Best wishes.
Jeff

[fprintf]

Best way I have found is to find a piece of dowel that is just over the inside dimension of the histart. First put some Household goop on the dowel, then shove the dowel inside each end of the two pieces. Once dry this should be enough to keep the histart together. For extra safety you can wrap dental floss, spectra fishing line or other strong string around the joint.

[Ricardo RW]

Originally posted by fprintf
For extra safety you can wrap dental floss, spectra fishing line or other strong string around the joint.

Better wrap it with a rubber band. A #64 rubber band will do OK.

Ricardo.

[fprintf]

Originally posted by guru_dick
Better wrap it with a rubber band. A #64 rubber band will do OK.

Ricardo.

That is what I do at the histart *ends*, but for a break in the middle and without connecting rings there is no way to wrap the elastic band around the joint! That is, unless you cut the elastic band and tie it when you are done wrapping.

Incidentally, if you have a nice histart w/ UV protection in it (Hobby Lobby, Aerofoam) then the potential weak link is the elastic band - it degrades rather quickly in sunlight. I need to replace mine after two years of activity.

[Ollie]

To protect the rubberband wrap from UV you can coat over the wrap with black RTV rubber. There are two kinds of liquid RTV rubber, silicone and sulfide. The sulfide RTV rubber used as a boat caulk and between deck boards is best. It is available in marine supply stores.

[Ricardo RW]

Originally posted by fprintf
... cut the elastic band and tie it when you are done wrapping.


Yes, I cut the elastic band and tie it firmly on top of the dowel.

But, I prefer to strip bike blades in bands similar about the size of #64 elastic bands. With this straps I don't have to worry about UV.


Regards.

Ricardo

[gdjsky01]

I don't mean to be dense, it's a gift really :D, but anyone have a picture of said joint? So to recap:

We take a dowel that has to be shoved firmly into the center of the surgical rubber, goop it, then join the two broken pieces. Break a few #64 rubber bands, and wrap those tightly around the joined pieces? Then liberally coat the tightly wound #64 rubber bands with boat deck RTV (good ol Home Dee Pot RTV is NG)?

How about just using a few larger tie wraps instead of the #64 rubber bands??
Jeff

[Ollie]

The reason that nonelastic bands like hose clamps and tiewraps aren't as good is that when the tubing stretches the wall thickness decreases over the dowel and the clamps loose tightness. However, when the tubing OD shrinks under stretch, the rubberbands comply and continue to provide enough clamping pressure.

[aeajr]

If you use dowels that fit tight, get 2-3 inches or more of dowel into each piece of elastic, the goop and rubberbands are just extra insurance. as you apply the tension to the line, the tubing will stretch and tighten around the dowel.

One thing that will help is to cut small rings around the dowel so the tubing as somethign to grab onto. You dont' want to use the type of dowel that is fluted the long way. That will reduce the contact area. Small rings scratched in with a knife will work great. They don't have to be deep, you are just creating some small grab areas. The rubber will squeeze into those rings and grab tight.

[T. Lyttle]

I have 2 breaks in my tubing, and I repair with a simple reef (not granny) knot, using soap & water as a lube (important); once dry, it seems to be fine. My repairs have never failed, am I just lucky?

[aeajr]

Nope, sounds good. If it works, that is the true test.

[aeajr]

What specifications do people recommend for a hi-start for 3 meter planes?

Or what model and brand woudl you recommend?

[fprintf]

http://www.aerofoam.com/hosemonster.html
http://www.aerofoam.com/hosemonster.html
http://www.aerofoam.com/hosemonster.html
http://www.aerofoam.com/hosemonster.html
http://www.aerofoam.com/hosemonster.html
http://www.aerofoam.com/hosemonster.html
http://www.aerofoam.com/hosemonster.html
http://www.aerofoam.com/hosemonster.html


say what?

http://www.aerofoam.com/hosemonster.html

:) :) :) :) :)

[aeajr]

OK, so which one? Could the witness be more specific?

I get it htat you like Hosemonster. This is what they recommend for 3 Meter planes.

3 meter 1/8"ID x 1/8"wall x 100' with connectors $75.00
3 meter rubber in 2-50ft. sections with connectors $85.00
3 meter rubber in 1-50ft. section with connectors $40.00


Are you saying that you like and use one of these Fprintf?

[fprintf]

I have been off of a hosemonster before and I liked it so much better than even my Hobby Lobby red heavy duty (3M) - something about a lot more stretch for a given amount of pull. I plan to get a hosemonster when my Hobby Lobby begins to die. It might be a while, though.

You got the sizes correct.

[aeajr]

One of the guys in our club has the same hi-start I have, a NE Sail Large ( or is it X large) Likes it so much he about to replace is 8 year old rubber with new. Went launching off mine, which is 2 years old, and ordered the new rubber. He pulls it back to 33 pounds of pull and rockets his Sagitta 900 really high!

So, it is challenge of the rubber

NE Sail vs HoseMonster - flyers pull your hi-starts! :)


edit 6/1: I have the NESail X-large, not hte large

[Ollie]

Some other histarts work very well but none better than those with mandrel formed rubber tubing like the Hose monster series.

[aeajr]

Explain mandres formed rubber for me if you would Ollie. Mandrel formed as opposed to what?

[ammo]

i only have the multiplex bungee hi-start for 4m sailplanes locally and shipping from the states will cost a lot if i'm to go for hosemasters or dynaflites.
I am planning to try hi-start with my 2m sailplane and maybe get a 3m later on.
How much is the difference between latex rubber and bungee hi-starts?
Also in terms of launch ease and height attainable?
lot's of stuff to learn but well, it has to be done sooner or later
:)

[aeajr]

These are general statements. Your launches may vary and there are different names for the same things in different countries.

As I will use it here, bungee is a fabric covered elastic typically used to make hold downs for cars, boats and trucks. It comes in various diamaters and strengths. It's typical use does not require a lot of stretch relative ot its lengh. For example, in attaching something on the roof on my car, I might stretch the bungee 1/2 is length to get a VERY strong hold and my not be able to stretch it to double its rested length. That is due to its strength and the fabric covering.

If you use this to make a high start, you get a very powerful but very short pull. This puts a lot of stress on the plane. It may also limit the height as the total extended length will be less than with tubing. For example (I am making up numbers but I think they will be OK for an illustration ) 100 feet of 1/8" bungee and 400 feet of line - 500 feet at rest. You might be able to pull it 50 feet till you get to an 8 pound pull on the line with the fabric cover preventing you from pulling it further anyway. 8 pounds of pull is a good strong safe pull for a typical 2M plane. Total extended length 12 feet. The contraction will happen over a 50 feet in few seconds then there will be no more energy applied to the plane. Like a rocket launch, short and powerful.

Latex tubing, surgical tubing, mandrel dipped rubber are all used without a fabric covering. In use as a hi-start they are typically stretched to 3, 4 or more times their rested length. 100 feet of 1/4 inch tubing and 400 feet of line, 500 feet rested length. For the launch you pull this 300 feet to a total of 800 feet and get an 8 pound pull. The contraction will be over 300 feet and much longer period of time delivering a gentler but firm launch and delivering power much further up the launch.

If there is a good breeze, say 5-8 MPH, the tubing may never fully contract before the plane leaves the line meaning the plane can reach higher while still receiving power from the tubing.

I have only launched off a bungee launcher with my planes a few times. That day we were comparing a 1/8 inch OD bungee high start to a 3/16 tubing hi-start. We pulled them back until we got similar pulls on the planes, based on feel. Not scientific.

We were launching two very similar Great Planes Spirit Select 2M sailplanes. There was about a 3-5 mph breeze that day. Light breeze

The explosive snap of power from the bungee was impressive, did not launch the planes nearly as well and clearly put more stress on them. Someone more experienced with bungee, and a better size match up might have worked better.

Others who have more experience can give you better info.

[aeajr]

I just came across this thread and thought it was worth a bump.

Anyone have any new tips on using hi-starts?

[arukum17]

I am particularly interested in hearing from others, ways to increase the visibility of the line after it falls to the grass. I am forced to use non-coloured monofilament because that was what was available...

[aeajr]

In the US, most hardware stores sell mason's line. This is the cord that brick layers use to make sure their rows are even.

It comes in bright colors. I use bright pink or bright orange. Shows up well against grass and dirt.

[davidjensen]

I too have the NSP extra large high start for 2+ years now. It works well and so far has been consistant. I am able to walk 100 full steps pulling which is just under 3 to one stretch on the 100 foot rubber. Our field is big but not quite big enough. I have to set up an an angle to the field to get a full stretch. Another thing I have learned is if you have camber control on the wing set your launch flaps near what you would use for normal thermal camber for the launch. Once you have made it through the transition at about 100 to 150 feet up start adding all the launch flaps you can. This will keep more tension on the line for a longer period of time. Once you get near the top remove the launch flaps and add reflex to help accellerate the ship for the zoom.

[aeajr]

David,

I have not seen this launch method suggested before.

Slight camber - ( thermal type camber )

Then switch to much deeper camber ( Perhaps 25%?) soon after launch?

Then switch to reflex for the bounce

Complex launch process. Do you recommend this for all full house planes or just moldies?

How much tension are you using? A NSP XL at 100 steps, about 250-300 feet must be pulling over 30 pounds. How are you holding on to it?

[davidjensen]

If I use full launch camber (flaps) when I toss the superior/Xpro/Thermal Dancer with the High Start it usually stalls at 100 to 150' up and I spend the rest of the launch fighting it. If there is some wind I can use more camber but when there is no wind they stall. Reducing the amount of launch flaps until you get through the (what I call) transition works great. After getting through the transition I start to add all the nomal launch flaps and it increases the tension on the line and results in a higher launch. Switching to reflex allows the ship to accellerate much faster and allows a zoom if there is any head wind. The radio takes the complexity out of the process. I use the left slider and one switch for launch. I add camber with the slider and the switch to place the ship into speed mode which has the reflex. So I set the small amount of camber and toss the ship. I add more camber (flaps) soon after passing the transition, then flip the switch near the top to help accellerate for the zoom. For my Thermal Dancer I walk about 90 steps which I equate to about 15+ lbs. The full 100 steps is closer to 20 lbs (probably less). Is it a work out? You bet.

[aeajr]

Seems my NESail XL is a lot stronger than yours.

Next time I use it to HS my Thermal Dancer I will try your approach. Thanks for sharing it.

[davidjensen]

My NSP XL is now 2+ years old and I doubt your is any stronger. If you ever get the chance, get a hand held fish scale and attach the high start to it and start walking. You will be amaized at what 15 lbs feels like.

[aeajr]

I have a fish scale and have been using it for 3 years on mine and other people's HS. It is a 50 pound scale.

At full pull mine registers around 30 pounds. I can't launch alone at full pull. I have launched my Legend ( 5 pounds )alone at about 250 feet, or about 23 pounds and could just barely hold on. :eek:

At 150 feet, 1/2 pull, it registers 12-13 pounds which is what I use to launch my Spirit and Sagitta 600. At that pull I can just about hold on to the Spirit without crushing the fuselage. I get some wrinkle in the wing monokote but not enough to be a problem. ;)

[DACeller]

Curious! Why don't you use a winch instead? What am I missing? Or is it- you just don't have one?

[jjc]

I see a lot of info on maximum pull. What is minimun pull I can get away with on launching a Thermal Dancer? John

[Richard L Bean]

Why would you want the min pull , that just nuts , get the thing in the air.

[Richard L Bean]

JJC
I did not mean for that to sound flip, but my brother and I launch , Supras , Avas, Ez bubble dancers and many more gliders ,and we never are trying to just get in the air, our min pull is 15 pounds all the way up to 30 plus pounds , I even have a just for practice landing Hi start that gets my Supra in the air about 200 feet , just enough for a couple of turns and a good landing. I have a new winch and thats so I can get some practice on winching for contest, so its all fun.

[jjc]

Shoulder problems, I can work around that with a winch, load it up quick and go. But hi-start has constant pull. John

[apage]

JJC,

You actually are thinking about this correctly. The 3M Aerofoam high start will launch your Thermal Dancer, and is about the minimum for that model. In calm conditions it will require care. With a breeze it will be easy. The range of models I use this high start for include a 54 ounce Bird of Time (plenty of pull), and a 79 ounce Pike Perfect (marginal without wind but still can get 2/3 height).

Aerofoam's black rubber is so vastly superior to the red stuff that in my opinion Aerofoam is the only option. The problem is that the red stuff tightens up within a very short elongation, and gives up all it's stored energy almost immediately. The black rubber has a very flat delivery curve - you can stretch it a long way, and it just keeps pulling and pulling and pulling all the way up the launch.

Most people make the mistake of thinking of a high start as a catapult. A full size (~500') high start functions as a towline rather than a catapult or slingshot. The more you can stretch the thing out, the longer it will "reel in". If the pull strength is matched to the model, the climb will be slow and steady, but for a long time compared to the red slingshots. You will easily get to "winch height", maybe more, with the recommended high start.

If you're looking for the highest launch, you want the longest high start that you can fit in your field with the rubber stretched 3 times it's rest length. Size the rubber so that at this max elongation you have enough pull to launch your plane, but not too much more. A typical rubber/line ratio is 100' rubber and 400' of line or less. I use braided kite line - very small and light. The higher drag of mason's line makes a difference, but the visibility of the neon colors may be useful for you. Mr. Kite of Minnesota makes the best chutes currently available.

There is something to be said for having a short high start with much stronger pull. You can get a decent landing practice launch with relatively little pull back distance. This way, if you're launching repeatedly, you only have to walk a fraction of the distance to retrieve the chute. And, you can operate from a much smaller area.

The difference in max pull of the rubber though is enormous. With the typical launch practice "garden hose" rubber, you pull it back until you're at your limit of strength. Most people can only do so many of those before the arm is too tired. With a properly sized full field high start, you pull it back to the edge of the field, easily with one hand. You can do this all day and your arm (shoulder) won't complain. As a bonus, the higher launches will probably mean you'll need fewer of them.

Andy

[bobby legue]

Andy,
That is the best description on highstarts Ive ever read.
Bob

[jjc]

Thanks Andy, that is the information I was looking for. John

[aeajr]

I see a lot of info on maximum pull. What is minimun pull I can get away with on launching a Thermal Dancer? John

I don't think you can over pull a TD on any hi-strat. I full pedal my TD on the club winch in up to about 10 mph winds. That winch has to be exerting at least 120 pounds of pull, so pull back all you like!

[philami]

Want one of the best 'Advice' on hi-start?

Don't use a parachute! Use a lenght of ribbon (2" wide 5' long). Pulls out of the bushes and weeds like a champ! You don't have to go the the end with the ribbon. No, just get somewhere near the middle of the nylon line and pick it up. Start walking back downwind and get thrilled to see the ribbon racing through the weeds and such like a lively snake of some kind! Try this and you'll never go back to a parachute! Trust me!

[kentuckyglider]

Want one of the best 'Advice' on hi-start?

Don't use a parachute! Use a lenght of ribbon (2" wide 5' long). Pulls out of the bushes and weeds like a champ! You don't have to go the the end with the ribbon. No, just get somewhere near the middle of the nylon line and pick it up. Start walking back downwind and get thrilled to see the ribbon racing through the weeds and such like a lively snake of some kind! Try this and you'll never go back to a parachute! Trust me!

I used to fly rockets, which use both streamers and parachutes. The problem with a streamer is that it does not drift downwind as much as a parachute (which is the point of using them with rockets), meaning you have to walk farther to get your line back. Of course, if you aren't launching upwind like you're supposed to (mea culpa :D ), using a streamer would be better.

KG

[KickAce]

I started flying again this past summer after a twenty plus year absence... Way back then I had to teach myself for there were no clubs in my area (and before the internet - love the internet now) that flew sailplanes... After I had built my 1st plane (gentle lady) I 1st bought 100' of bungee cord and 400' of line... Can only stretch the cord only so much, I slowly increast the pull (to a full pull) and at one time during launch the plane was 1/4 way up and seeing the wing fold and helpless watching as it came crashing back to earth (if i crashed it once, i must have crashed it a hundred times) I figured there must be a better way... I heard about hi-starts and being a cheapskate (hense the bungee) I had bought 100' of 3/8" surgical tubing (extruded - amber) from a local medical supply house and the difference was night/day... It was true surgical tubing and no UV protection... Well needless to say it did not last long before it became brittle and was breaking all the time... Never did catch a thermal... That was then and this is now... I picked up flying again and had bought this time the heavy-duty hi-start from Dynaflight and it worked pretty well but once again after heavy use it deteriorated rather quicky and this to was breaking all the time and the pull was noticeably weaker than when it first came out of the box in no time at all... Now I have purchased several "HoseMonster" hi-starts...

( http://www.aerofoam.com/hosemonster.html )

I had puchased a Pinnacle hi-start off of ebay for a really good price but have not had the chance to try it out yet but looks very promising...! It is quite different than the hosemonster and seems to be a different type of rubber than the mandrel-dipped and has a very thin wall, if anyone could shed some light here would be very appriciated... I know next to nothing on this one and their site does not say much about it... What and or how is it made/made-of, how can you tell which size Pinnacle hi-start it is such as diameter vs the mini, small, standard, medium, large or extra-large...? Still seems hands-down much better than the Dynaflight systems and much cheaper in cost than the hosemonster's...

( http://www.nesail.com/categories.php?subcatID=54 )


The HoseMonster rubber I have in the 2, 3 and 4 meter class... They are mandrel dipped and heavier wall thickness than the Dynaflight Heavy-Duty and seems to have a much smoother pull to them... I have them "ringed" at their 50' marks and can adjust the length with qiuck release hooks depending on the size field that I am flying at... I am using 500' of 200lb massion line also "ringed" at the 250' mark for adjusting to the size field... This seems to be a good way of doing this and I can also add sections together if more pull is needed by using (joining) the rubber in parallel (tandem) such as a 50' length of 2 meter rubber along-side with a 50' 3 meter rubber... I did spend close to $400.00 (i've spent at least as much on all the cheap ones added together) on all that rubber but have found it to be well worth the cost... No more cheap rubber for this guy, I have learned my lesson...! I also use the aerospace protectant "303"

( http://www.303products.com/tech/index.cfm?fuseaction=product.display&Product_ID=428&CFID=5769181&CFTOKEN=38121153 )

to keep them in top-notch condition and adds to the UV protection... I also have them stored in insuated Kelty Binto Cooler to keep them out of UV light and away from ozone which will also deteriorate the rubber... Store in a cool place...

( http://www.campmor.com/webapp/wcs/stores/servlet/ProductDisplay?AFC-kelty&pos=43103&partNumber=43103&memberId=12500226&storeId=226&catalogId=40000000226&langId=-1 )

I thought that I would mention since I have not really heard anyone talk about the care and maintenance of the very expensive rubber...! It makes a difference between making your hi-start last a long time or make it last a VERY LONG TIME...

Well, for what it's worth...
Kevin :rolleyes:

[aeajr]

Have you had a chance to fly the Pinnacle? I would be interested in your thought of how it compares to the Hosemonster hi-starts.

[KickAce]

Hi aeajr...

No I have not... I will be waiting for spring to arrive... :p

I now have two of the pinnacle's and look forward to trying them both out and compare them with the hosemonster that I did not get to use until toward the end of the flying season...

I just cannot figure out which of the pinnacle hi-starts that I have... :confused: I had bought them off of ebay and the sellers didn't know either... :( and I even tried to write nesail but have not received any responce... :eek:

It seems to me that the pinnacle hi-starts are made using the extruded method but no verification on this...

The demensions of the tubing that I have are:
7/16" OD with a 1/16" sidewall and a 5/16" ID = ?
7/16" OD with a 2/16" sidewall and a 3/16" ID = ?

I have read that you have a few pinnacle's and wonder how they match up with the ones that you have...?

Kevin

[aeajr]

That looks like the Large and the XL which are designed for 3M and 4M planes respectively. I have the first one, which I thought was the XL, but if there is a pinnacle with a 2/16 wall, then that must be the XL and I have the large.

I likewise purchased mine off e-bay from someone who tried sailplanes but did not like it. It has served me well but it is stronger than I need for all but my Legend.

At full pull, it will produce about 30 pounds of pull.

[KickAce]

Yes, the 1st one is the first (lol...) one purchased through ebay and is 100' in length... It is by far the thinnest tubing that I have seen and will be trying out this spring... It feels like it will have pretty good pull to it... I cannot tell if this one is made through the extruded or mandrel-dipped...? One end (about 25') had been flattened likely due to being too tightly wound around the spool... I had cut 3" from where it was tied onto the ring and before I re-tie the rubber to the ring I blew into the end to give it a bit of air pressure and tied the rubber to the ring... In doing so it took the flatness out of the tubing and wound it back onto the spool loosely...

The second one does have much thicker sidewalls of 1/8"... It is only 50' in length... It came with everything except the take-up reel... I am pretty sure that this has been made through the extruded method... It has very strong pull to this one... So, I wonder could this be the Pinnacle Zoom Start...? http://www.nesail.com/detail.php?productID=873
The zoom-start is the only one listed on their site that only comes in a 50' length but then again they list no rubber spec's... The take-up reel I just bought one from walmart for under 6 bucks... I should say that if anyone does buy the orange extension cord reels (which work fantastic) to be very sure to de-burr them before winding any of your line and expensive tubing on it... They come with very sharp plastic mold lines and should be gone over with sand paper prior to use...

But anyhow, without the spec's on the tubing for the pinnacle hi-start launching systems it is not easy to know which hi-start you really have... I'd like to get all who have them and know which model hi-start they have that maybe we could finally get them all listed in this forum...

Pinnacle Spec's
http://www.nesail.com/categories.php?subcatID=54
Pinnacle Mini Hi-Start ----------- ? -- up to 1.5 meter wingspans
Pinnacle Hi-start (Small) -------- ? -- up to 2 meter wingspans
Pinnacle Hi-start (Standard) ---- ? -- M and L sizes wingspans
Pinnacle Hi-start (Medium) ------ ? -- 2 meter wingspans
Pinnacle Hi-Start (Large) -------- ? -- larger standard and open class
Pinnacle Hi-Start (Extra-Large) -- ? -- 4-meter wingspans
Pinnacle Zoom Start ------------ ? -- TD competition sailplane

HoseMonster Spec's
http://www.aerofoam.com/rubberspecs.html
2m. rubber-----------------1/8"ID x 1/16" Wall -- 6LBS PULL
2m Comp. rubber-----------1/8"ID x 3/32" Wall -- 8 to 10LBS PULL
3m rubber------------------1/8"ID x 1/8" Wall -- 14 to 18LBS PULL
Unlimited rubber------------1/8"ID x 5/32" Wall -- 20 to 24LBS PULL
Standard Bungee-----------1/4"ID x 1/8" Wall --- 28 to 35LBS PULL
Mega Bungee---------------1/4"ID x 3/16" Wall -- 38LBS ++ PULL
Insane Mega Bungee--------1/4"ID x 1/4" Wall --- 50LBS +++ PULL

Hobby-Lobby Spec's
http://www.hobby-lobby.com/histart.htm
UP-Start outfit for Handlaunch -- ?
Rubber for under 2-meter (78") - 3/16" ID with 1/16" wall Color: Red
Rubber for under 3 meter (118")-- 1/4" ID with 3/32" wall Color: Orange
Rubber for under 4 meter (157")-- 3/8" ID with 1/8" wall Color: Yellow

Dynaflite Spec's
http://www.dynaflite.com/accys/dyfp8301.html
Standard Hi-Start ----- 1/8" ID X 3/64" wall = 7/32" OD for 2-meter sailplanes
Heavy-Duty Hi-Start - 3/16" ID X 1/16" wall = 5/16" OD for sailplanes 100" span +

In all I am very pleased in the purchases of both the hosemonster and the pinnacle even though I have not used the pinnacle's as of yet but have seen/spent/used enough to tell quality rubber to those that will fall apart in a short time...

Kevin

[williamson]

Several years ago, I did a survey of high starts and looked at the relationship between the dimensions (diameter, wall, length..) and the force at elongations appropriate for launching sailplanes of different weights. This analysis is at

http://www.charlesriverrc.org/articles/design/dickwilliamson_histartphysics.htm

The table allows a quick estimate of the appropriate cross-sectional area of rubber for a plane of a given weight. For dimensions not listed in the table, calculate the cross sectional area of the tubing in square inches and multiple by 175 lbs. per sq./ in. to get the weight of a plane well matched to the tubing. This estimate matches very well with the HoseMonster data in your summary.

Note: HoseMonster now sells the rubber that used to come from Hollyday.

[KickAce]

Thanks Richard…

Most excellent information… I had come across this once before… One thing missing was the formula on calculating the area of the cross-section for the tubing… It did not say whether the tubing tested was made via the extruded or mandrel-dipped method…? I suspect that the ones tested were the extruded variety and maybe you could shed some light here… Have you tested both types and is there not a difference in the elasticity between them where one tends to snap-back to the relaxed state at a stronger rate (speed) than the other…?

I have made a calculator that I have attached to this reply that will help in others to do the same kind of calculations… Sorry but my VB is a little rusty… It follows very much in line with the chart in the link that you posted http://www.charlesriverrc.org/articles/design/dickwilliamson_histartphysics.htm I hope that others will be able to use it and put it into good use… It should work on most PC’s… I have included a screen-shot of the program for you to look at and can decide whether it is something that you may want to download and try for yourself… I have made it as "Freeware"

Even more of a reason to ask those who have purchased one of the Pinnacle Hi-Starts if they would be most kind and submit a reply with the TYPE of hi-start (such as the ones listed in the prior post) that they have purchased and what the OD & ID of the tubing are…? Please, I ask that you can verify that it IS indeed that specific model. When I edit my post with the replies on the spec's only reply with model Pinnacle Hi-Start and do not reply with duplicate spec's unless you KNOW someone's reply is incorrect…

I look forward to everyone’s replies…
Kevin

UPDATE: I removed the zip file from this location and have started a new topic called "Hi-Start Calculator" on this site to which you can download the file... Here is a quick link to jump to it:
http://www.rcgroups.com/forums/showthread.php?t=795380

UPDATE: 01-05-2008
HERE IS THE UPDATED VERSION OF "THE HI-START CALCULATOR" PROGRAM VERSION 1.0.1 - This is the final version of this calculator software BUT I am still looking for input for the "Hi-Start Beginners Guide" - Please give me input Click on the link shown above to get to the site for the download and post comments and suggestions for the “Hi-Start a Beginner’s Guide”

UPDATE: JAN 13 2008
Hi-Start Calculator version 1.2.0
I have uploaded a new release of the Hi-Start Calculator 1.2.0 that has the option to calculate using the ID and Wall Thickness… There has been a need for this option and due to the fact that version 2.0.0 will not be out until sometime this summer I had upgraded this version for use until then…
http://www.rcgroups.com/forums/showthread.php?t=795380
Enjoy…
Kevin :cool:

[PLRDad]

Aeajr,

You provided invaluable information when my 10 year old son (now 14) and I were learning how to fly the Aerobird Challenger. Now I need some new advice. I have just finished building a Spirit 2M and flew it for the first time last weekend. Seemed to go OK until the wind picked up and I had two pop offs. Managed to land Ok. I guess the electric rc flying paid off. In the process of building I had a couple of questions. What is the preferred method of installing weight in the plane? I epoxied it in but that of course makes it difficult to adjust the weight if necessary. Your advice would be appreciated. Also how do I go about trimming the plane beyond balancing at the suggested CG and laterally.

Thanks
Randy

[aeajr]

I typically use flat weights with double sided foam tape. They go as far forward as possible. They hold well but are easy to pry off.

[PLRDad]

The hi-start I am using for the 2M Spirit was given to me by some local pilots who have since gone on to hlg and winch launch craft. It is constructed from 3 or 4 strands of surgical tubing with a length of ~30 ft and addition string line of 100 ft. It seems to work fine but my launches are not very high and thus I don't have much time to search for thermals. My average time in the air is about one minute. Am I correct in coming to the conclusion that I need a standard hi-start to allow me the time I need in the air to become competent with this plane. I have no troubles with the controls but need time to trim and hunt for good air.

Thanks for your comments.

Randy

[aeajr]

Yep, you are flyign off a little hi-start, often called an up-start. Typically used for practice or restricted space.

A full size hi-start would be about 100 feet of tubing and 400 feet of line.

[kentuckyglider]

Yep, you are flyign off a little hi-start, often called an up-start. Typically used for practice or restricted space.

A full size hi-start would be about 100 feet of tubing and 400 feet of line.

However, keep in mind a full-size hi-start will require roughly 2-3 times as much length. An area with a minimum length of 2 football fields in at least one direction can be difficult to find.:(

KG