Drogue/Main question

OK, if my main is smaller than optimal, can I use a larger drogue (5 or 6 feet versus 3 -- i'm not worried about extra drift from it) so that it'll help slow rocket when main pops too? Rocket is 12 feet long, 33lbs after burnout, will have 40 feet of TN each for booster-to-center-section/center-section-to-nose cone. So it'll be stretched out vertically around 80 feet or so. Ground is hard playa. I'm looking for a few less fps drop at touch-down. Or will a larger drogue not do much, or worse, limit main's potential?
Thanks, Tallman

To be honest, the problem I'd be more concerned with is that of entanglement.

Your main will come out relatively close to your drogue, and the larger the drogue is, the greater the risk of the main getting tangled in it.

-Kevin

Also think about if your Drogue is too big! it may slow the Rocket to the point in which when the Main does pop it wont catch air, At least Not right off the bat. Set the Main 4-500' higher than you normanly would just to give it more! time too open.

Why would you want to use a larger drogue?? I go drogueless on my DD flights and most of the other more experienced HPR guys in the clubs I am a member of do as well..I know you're concerned with the 'optimal' speed for the deployment of your main but I think it is a moot point, really..If you have the sections balanced pretty well they will tumble and spin around creating plenty of drag so that main deployment shouldn't be a problem..Ask Blackjack2654 what size drogue he has in his 'Gone Bananas Again' rocket!

Pantherjon said:

Why would you want to use a larger drogue?? I go drogueless on my DD flights and most of the other more experienced HPR guys in the clubs I am a member of do as well..I know you're concerned with the 'optimal' speed for the deployment of your main but I think it is a moot point, really..If you have the sections balanced pretty well they will tumble and spin around creating plenty of drag so that main deployment shouldn't be a problem..Ask Blackjack2654 what size drogue he has in his 'Gone Bananas Again' rocket!

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Me too. I never use drogues anymore.

Just re-read OP..If you want a few less ft/sec on touchdown, use a bigger main!

I still say to ditch the drogue chute tho...

A slightly larger drogue isn't going to do much.

I'd suggest picking up a 15 foot Round, white mil-surplus chute for $74.00 from https://www.alwaysreadyrocketry.com/products/chutes.html



or a 15-17 foot Round, white mil-surplus chute for $110.00 from https://aeroconsystems.com/chutes/p17ft.htm



Either will pack tightly in a 5.5" tube as shown below, weighs less than 3 pounds and will bring down a 33 pound rocket at 14 fps at sea level and about 16-17 fps on the playa. It's well worth the price.



Bob

I agree with Bob. After the main deploys, the drogue is basically just going to hang there without catching much - if any - air so it will have minimal effect on slowing your rocket down. Your only choice is go with a larger main.

bobkrech said:

Either will pack tightly in a 5.5" tube as shown below, weighs less than 3 pounds and will bring down a 33 pound rocket at 14 fps at sea level and about 16-17 fps on the playa. It's well worth the price.

Click to expand...

As an aside, for those who don't already know it, never pack a nylon chute this way. It's a recipe for disaster, for a couple of reasons.

First, with nylon chutes, the lines sometimes loop over each other and get jammed, causing the parachute to fail to deploy. Yes, I know someone is going to reply and say "I always do mine this way, and after xyz times, I've never had a problem." Guess what? I've seen the problems, and I've seen the result. It ain't pretty.

Second, the lines stripping off the chute creation friction, which generates heat, which is the enemy of your parachute. It degrades the nylon, increases the changes of the parachute failing.

Skydivers specifically pack their parachutes to avoid lines rubbing on the canopy (or lines), as well as the nylon rubbing on itself. Why? Because of the heat generated, and the damage it does.

And yes, you can pack parachutes into an amazingly small space, given some time and patience.

-Kevin

Thanks for all the suggestions. I actually have one of those white chutes and it seems to be around 14 feet -- measuring it closed like an umbrella, from top to hem. The tubes are 7.6" so there is plenty of room. The two links to chutes I think are for the same one. Playa altitude is arounf 2300 feet, and so Bob you are exactly right, it'll come down a bit faster. If the drogue can't aid it, then I'll try to make the whole thing a bit lighter (lose the quick links, etc.). The reason I asked about the drogue is I can't spend any more on chutes.

Thanks, Tallman.