New hi start...wow!

[RSCherry]

Just tried out my new hi start from aerofoam.com with my open class TD plane- wow! best hi start I have ever used! The black rubber Mark sells stretches much longer than any of the other hi starts I have used in the past. My launches were smooth and very high.

I bought a convertible set-up, which breaks the rubber into 2 50' sections and the line into 2 250' sections. I was flying from a small field, so I could only use the shorter arrangement (50' + 250'). With a zoom at the end of the launch, I could still see the rubber pulling the chute down after release.

This is a nice set-up, I highly recommend it.

Bob

[Gliderguy]

That sounds great. What plane are you flying and what size rubber did you get? Also how far back could you stretch it? I just ordered the 3 meter 50 footer from Aerofoam that I want to use as a practice launcher for my Cumulus F3J (hope it's enough pull for a 70oz plane). Might want to get another 50 ft section.:D

Gliderguy

[RSCherry]

I'm flying a Slegers Spectrum, which is 106", about 64 oz. I'm using the open class rubber, same as you ordered. The Aerofoam rubber really stretches- I was launching at 90 paces of pull, but it could have gone further (I ran out of field!). That is a lot more than other hi starts I have used in the past. This rubber has a nice smooth energy delivery- does not rip the plane from your hand then run out of energy half way up the launch like other I've used. Just be sure to pull it back far enough. My first few launches were from the same "spot" where I have used my other hi starts, but that was not nearly enough stretch. You'll like it.

Bob

[ferradas]

I also ordered 3 meter rubber from Aerofoam. Im launching a HKM Space Pro 3.27m 70+ ounces. It pulls it up very nicely. I take about 100 steps back. It's a nice gentle pull and it gets alot of altitude. GOOD STUFF

[Gliderguy]

ferradas.
Are you using the 50 foot section as well or the 100 foot.
100 steps is really stretching it out there. Might be a long walk for a 100 foot section. :D

[ICTHRMLS]

A good rule of thumb (or foot ;) ) is three times the rubber - 100 foot rubber - 300 foot stretch. OR one step per foot - 100 foot rubber = 100 steps. This really helps when you set things up too. :cool:

[ferradas]

Im using 100 feet rubber.

[RSCherry]

Here's an excerpt from an email from Mark Mech at Aerofoam regarding the proper stretching of the Aerofoam rubber:

"Most people stretch it about 300% more than it's resting length, but it is capable of stretching 600%. I wouldn't stretch it this far in temperatures below 45 deg. though. Cold weather is hard on the tubing if you over stretch it. A 300% stretch would be an additional 150' from it's resting length, or a total of 200' from the stake. this is about 60 paces."

[Ricardo RW]

Guys,

I've seen a lot of talking about 'zoom,' but, what is it? A plane attidude when the rubber gets unstretched?

I hope you can help me.

TIA

Ricardo
Chile, South America

[RSCherry]

The "zoom" is done near the end of the launch, after the plane is at the peak of it's rise but before the hi start releases from the hook. Basically, you point the nose of the plane down for a short time to pick up speed from the remaining stretch in the rubber, then pull up hard to a steep fast incline, rounding out to level flight higher than where you started.

That's the theory, anyway. Getting some height out of it takes some practice. Works best with a winch, where you can really build some speed on the down leg of the zoom.

Hope that helps.

Bob