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Old Dec 30, 2007, 01:31 AM
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Hi aeajr...

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

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... 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...

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
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Old Dec 30, 2007, 12:04 PM
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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.
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Old Dec 30, 2007, 01:49 PM
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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
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Old Dec 30, 2007, 08:32 PM
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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/articl...artphysics.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.
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Old Jan 02, 2008, 11:32 PM
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Hi-Start Calculator

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/articl...artphysics.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
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Last edited by laurionk; Jan 13, 2008 at 08:19 PM. Reason: added files
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Old Jan 10, 2008, 10:26 PM
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Seeking Information-Slightly off Topic

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
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Old Jan 10, 2008, 10:55 PM
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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.
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Old Jan 22, 2008, 11:55 AM
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Hi-start problem?

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
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Old Jan 22, 2008, 12:08 PM
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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.
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Old Jan 22, 2008, 05:58 PM
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Quote:
Originally Posted by 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.
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
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Old Jan 22, 2008, 10:34 PM
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Fully stretched, a full size HIS is 800 feet long. Quiet a sight as it goes up.
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Old Jan 24, 2008, 08:49 AM
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I have not stepped it off but I believe the field I fly at is adequate for a launch with a full high start. Regardless, I am commited as I have ordered a Dynaflight HD hi-start due in on Friday. Now if the weather will cooperate this weekend.
Randy
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Old Jan 27, 2008, 05:44 AM
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That will do very nicely with the Spirit. Note that there are three hook positions on the Spirit. The most forward is the safest, most stable for launching. The most rear is the competition position. Steeper launch but can be harder to control. Which are you using?


Also, in relation to weight and balance, as you get to know the plane, try to remove weight from the nose. A nose heavy plane will not indicate lift very well and will not launch as high. How much lead do you have in the nose?

You can easiliy test by taping a coin on the tail. Try a dime and see if you the plane changes, or if it gets hard to manage. Try a quarter. Try two quarters.

Over a series of flights, perhaps over a series of visits to the field, try to move the CG back using this method. Since you epoxied the nose weight in, it will be tough to remove. This is an easy test method.

Each gram ( 1/28 of an ounce ) on the tail is about equal to 3 grams in the nose.

A dime is about 2 grams. A quarter is about 6 grams, or a little less than 1/4 ounce. So if it is comfortable with a quarter on the tail, try pulling 1/2 - 3/4 oz out of the nose and see how it goes.

My thermal Dancer is balanced well for most conditions, but when it fairly calm, I tape a quarter on the tail. It is too "twitchy" in breezier conditions for my liking, but in low wind, I can pick up thermals I would have missed without moving the CG back.

The goal is to get the nose as light as possible while having enough stability to manage the plane.
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Old Jan 28, 2008, 12:36 PM
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Unfortunately the hi-start did not arrive this weekend as expected. Maybe by next weekend

The tow hook is in the front position. I have tried to place the CG at the spar but with a slight nose down. I was able to remove the weights, epoxy and all and now have them mounted with foam tape as you recommended.

On my last couple of outtings I have been having trouble with the plane popping off but not at such a low altitude that I could not fly it out and land safely. I think it was because the radio was moving in the fuselage. I have since reattached with foam tape. I'm hoping this will take care of that problem.

Once I get the new Hi-start I will work on fine tuning the CG as you described. Hopefully I will now have enough flight time to make useful adjustments.

Randy
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Old Jan 28, 2008, 01:25 PM
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I had pop off problems with my Spirit. Turned out the hstab was up in the back. Even though the elevator was trimed neutral, I would pop off. Try some down trim.

Balance at the spar? Not sure that is right. Where do the plans tell you to balance. It is usually some # inches from the leading edge, which may not be at the spar.
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