My Denali wieghed in about 15 to 20 pounds. I had a 15' chute and 3 'drouge. For a 9lbs rocket 60" may be a bit on the small side. Maybe a 84"? And I would try to avoid two chutes. If one does not open your coming down on a 3' main and 3' drouge and that would be below average.

Keep in mind that area, not diameter, is what matters. So, a 72" would be the equivalent of 4 36's, not 2. I also agree that a single 60 sounds a bit small - I would go with a 72 to 96 incher, depending on how slowly you want it to come in. A Rocket Rage RRQS15 would be ideal, though a bit more on the expensive side (best quality chutes I've ever seen though).

A Rocket Rage RRQS15 would be ideal

Mike, you should greatly oversize your Rocket Rage chute if you like your rocket to land softly. The RRQS15 will bring it down but more on the 25 fps rate. I have a RRQS30 you could borrow at Oktoberfest.

Doug

Advice well taken. I will build ahead as I do most of the time. Bigger is
better. I quess at this point. I would rater launch a couple Js with a shorter
bird.

I'l see what goes on between now and then.

I'l probably slow down and get my level 2 out of the way then decide.

Thanks

A Rocket Rage RRQS15 would be ideal

Mike, you should greatly oversize your Rocket Rage chute if you like your rocket to land softly. The RRQS15 will bring it down but more on the 25 fps rate. I have a RRQS30 you could borrow at Oktoberfest.

Doug

With 9lbs?

The 15 would be fine- it would come in at 10-12 fps.

With 9lbs?

The 15 would be fine- it would come in at 10-12 fps.

Chris, how many times you've used Rocket Rage Chutes? Did you measure the descent rate using them? I have used them and I can tell you it won't come down slower than 12 fps. I love the chutes and I agree it will come in fine at with the RRQS15 but not at 12 fps. But I'll do more than talk. Are you willing to put money behind your claim?

At Oktoberfest, if Mike agrees we'll use his rocket and fly it with a RRQS15 I'll provide and measure it's descent rate. If it comes down faster slower than 12 fps Mike keeps the chute. If it comes down faster than 15 fps you buy him a RRQS30. If it comes in between 12 and 15 fps we call it a draw. Are you game? We'll even get an independent judge to download the altimeter data and declare the results. Consider it a good way to help out a beginner since we've both been flying for such a long time.

Doug

I have never measured the descent rate on the 15, no. My 50 however comes in at about 9-15fps with 29lbs of load at the north site. The 15, assuming similar drag characteristics, should come down even similarly with 9lbs. I've dropped 14lbs perfectly fine under the RRQS15 (though without a recording alt unfortunately), and it appeared to be descending in the 20fps range from eyeball guesstimation. I won't claim any level of accuracy with that though.

As for money behind my claim? Not right now - I don't have the money to risk. I'm trying to build my L2 project for MHM, and between that and college, I can't afford another $130 chute. Sorry. I would love to see data about the chute if you have some implying that I'm wrong - though if their published numbers are correct (15lbs at standard conditions at 22fps), 9lbs at the north site (5400 feet) should be about 15fps. My experience has shown that the chutes tend to come in even slower than this, as on my measured flight with the RRQS50 should have come in at 15fps as well, when the measured values ranged between 9 and 15fps.

Those RocketRage chutes are the best. I'd gladly trade every piece of PML, LOC, and Army surplus junk I own in for one.

I borrowed Doug's RRQS70 for my L3 and it was a thing of beauty..... No, wait.... any parachute deploying on an L3 is a thing of beauty.

Really, thanks again Doug!

Your descent rate questions got me thinking, so I went back to the altimeter data from my "Just Do It" flight.

The descent rate under the RRQS70 main was right at 20fps for a rocket that would have weighed 38 lbs 6ounces after propellant burnout.

Ed

I went back to the altimeter data from my "Just Do It" flight.

The descent rate under the RRQS70 main was right at 20fps for a rocket that would have weighed 38 lbs 6ounces after propellant burnout.

Ed, that matches my data. On Freeze Frame using a RRSQ130 it's descent rate was 25 fps with a weight of only about 60 pounds. BDCR's flights showed the same results on the RRQS70. That's why I use the rule of thumb to use double the size you need to get the 20 to 25 fps. I always try to rely on empirical data rather than

eyeball guesstimation

Doug

I went back to the altimeter data from my "Just Do It" flight.

The descent rate under the RRQS70 main was right at 20fps for a rocket that would have weighed 38 lbs 6ounces after propellant burnout.

Ed, that matches my data. On Freeze Frame using a RRSQ130 it's descent rate was 25 fps with a weight of only about 60 pounds. BDCR's flights showed the same results on the RRQS70. That's why I use the rule of thumb to use double the size you need to get the 20 to 25 fps. I always try to rely on empirical data rather than

eyeball guesstimation

Doug

I love out of context quotes 🙂

As I said, I am ignoring the data from the RRQS15 because that's all that it is based on. I have actual data however from a RRQS50 with 29lbs of weight (after burnout), and it shows 9-15fps. I can post that data if you like - it was taken with my R-DAS, and is quite clear.

I broke down and ordered a 70" Top Flite. Should do the job.

Thanks for all the help.

Mike, I saw the picture of your rocket posted elsewhere. Good luck! Please post the descent rate here after you fly it. Maybe we should start a pool to guess the descent rate? Again, Good luck on your level 2!

Doug

The white paper says.

12lb to 18 lb = 17 to 22 Ft. Per Sec. Using a 70" standard flat chute.

I 'should' be less than 17 at around 10lbs loaded. I'm OK with drift.
I just want a soft landing. Plus future birds will be heavier.

I would need some help calculating the descent rate on site.
I never have.

Thanks