A 5 second burn is much longer than what would be needed "under canopy". Check your gut reaction to the numbers again.
I think the thread was unfortunately misdirected quite early by what has to be a mistake in the FAA filing.
3) Propulsive Assist Hopping Approximately 400 gallons of propellant would be loaded into the DragonFly RLV for this test. During a propulsive assisted hop test, the DragonFly RLV would launch from a launch pad and ascend toapproximately 7,000 ft AGL (firing engines for 12.5 seconds). Two parachutes [not three] would be deployed for the descent, the engines would fire for 12.5 seconds, and the RLV would make a powered landing on the launch pad. This operation would last approximately 60 seconds. {ed. note: I find this scenario interesting because they're still talking about landing on the landing pad- even under parachute assisted conditions. This looks like a release of the deployed parachutes with powered recovery scenario.}
I did read those. In fact, it wasn't until I read those that the scenarios seemed wrong.Quote from: sghill on 06/10/2014 07:42 pm3) Propulsive Assist Hopping Approximately 400 gallons of propellant would be loaded into the DragonFly RLV for this test. During a propulsive assisted hop test, the DragonFly RLV would launch from a launch pad and ascend toapproximately 7,000 ft AGL (firing engines for 12.5 seconds). Two parachutes [not three] would be deployed for the descent, the engines would fire for 12.5 seconds, and the RLV would make a powered landing on the launch pad. This operation would last approximately 60 seconds. {ed. note: I find this scenario interesting because they're still talking about landing on the landing pad- even under parachute assisted conditions. This looks like a release of the deployed parachutes with powered recovery scenario.}12.5 seconds of engine firing while the craft is already under parachutes? That's the bit that doesn't make sense to me. Just how low do you think these engines can be throttled?edit: Oops, just noticed your note. That's interesting and it could explain my perceived discrepancy. Thanks.
Perhaps the thrusters continue firing at a lower level after landing in order to consume all the propellant?
Quote from: deruch on 06/10/2014 08:38 pmI did read those. In fact, it wasn't until I read those that the scenarios seemed wrong.Quote from: sghill on 06/10/2014 07:42 pm3) Propulsive Assist Hopping Approximately 400 gallons of propellant would be loaded into the DragonFly RLV for this test. During a propulsive assisted hop test, the DragonFly RLV would launch from a launch pad and ascend toapproximately 7,000 ft AGL (firing engines for 12.5 seconds). Two parachutes [not three] would be deployed for the descent, the engines would fire for 12.5 seconds, and the RLV would make a powered landing on the launch pad. This operation would last approximately 60 seconds. {ed. note: I find this scenario interesting because they're still talking about landing on the landing pad- even under parachute assisted conditions. This looks like a release of the deployed parachutes with powered recovery scenario.}12.5 seconds of engine firing while the craft is already under parachutes? That's the bit that doesn't make sense to me. Just how low do you think these engines can be throttled?edit: Oops, just noticed your note. That's interesting and it could explain my perceived discrepancy. Thanks.As far as throttle range, the similar hypergolic engine on the Apollo DPS acheived throttle down to ~10% which means 2 engines in each pod can maybe throttle to 5% by turning one off. Assuming at minimum 4 engines firing, 10% thrust would be 1,640 lbf X 4 or 6560 lbf. If the craft can throttle this low, thrust to weight of 1 is easily acheivable and so hover, slow descent or slow ascent is limited by the available fuel supply.
AIUI, FAA has to issue the final EIS and permit. There is a 30 day comment period after the EIS before things can actually move on the permit.
Quote from: docmordrid on 06/15/2014 06:33 pmAIUI, FAA has to issue the final EIS and permit. There is a 30 day comment period after the EIS before things can actually move on the permit.ahhh the red tape
Besides the red tape, I'm sure they aren't' ready. SpaceX knew about the red tape, so they applied before they were close to testing DragonFly. And there is still work on the F9R at McGregor which probably has to finish up (with test of that vehicle moved to Spaceport America) before DragonFly tests start at McGregor.
Read the report closer! Get off of the chart on Page 2-1, and go to Page 2-5 and 2-6. They've described 4 scenarios in detail. Quoting from the document (emphasis mine) They are:...Also, from Page 1-4, the F9R program has a permit for 10 launches. They've done 2 so far (perhaps more if the FAA is including the ground testing burns), and the DragonFly permit won't kick in (if approved) until after those ten launches.
Quote from: sghill on 06/10/2014 07:42 pmRead the report closer! Get off of the chart on Page 2-1, and go to Page 2-5 and 2-6. They've described 4 scenarios in detail. Quoting from the document (emphasis mine) They are:...Also, from Page 1-4, the F9R program has a permit for 10 launches. They've done 2 so far (perhaps more if the FAA is including the ground testing burns), and the DragonFly permit won't kick in (if approved) until after those ten launches.Are you sure about that? Why would all of the F9R Dev flights have to be completed before any DragonFly flights? And given the few F9R Dev flights so far, the DragonFly flights could be a long way into the future. As I speculated before, ISTM that SpaceX would like to have at least some (if not all) DragonFly flights before doing the Abort Tests.
As docmordrid said, the F9R permit runs out on the 26th Feb 2015, so DragonFly can start after that.
Quote from: GlaDOS on 08/04/2014 03:46 pmAs docmordrid said, the F9R permit runs out on the 26th Feb 2015, so DragonFly can start after that.Why wait?