The EGE
Well-Known Member
- Joined
- Sep 11, 2009
- Messages
- 546
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I'd like to try dual deployment on a 29mm minimum-diameter altitude model I'm working on. It'll be going to altitudes of around 6k on Is and 5k feet on H motors, so apogee-deploy by motor ejection is not a viable option.
First, an incredibly stupid question. Would it be possible to have the motor eject the drogue at apogee and then use a timer to eject the main? Perfectflite's staging electronics claim delays of 'at least 60 seconds' possible; even from 6000 feet, 45-50 seconds (from apogee) at 90-100 fps* will bring it down to 1500 feet or so.
* Yes, I know that's rather high for deploying the main, but this is a 10-ounce rocket with kevlar shock cords so it can survive it.
This is very appealing to me because the staging electronics are half the cost and size of the smallest dual-deploy altimeters, and I'd rather only deal with one ematch than two. However, because I can't know exactly how fast it will descend, it'll only be accurate to within around 500 feet or so of altitude, rather than knowing that the main will deploy exactly at 1000 feet or whatnot.
Second, how do I go about making such a tiny av-bay? I cannot use the standard design with a sled because the electronics are almost exactly the same width as the tube and thus must be centrally located. Also, the tiny bulkheads - 1" diameter - might not be able to hold three separate rods (two thread rods + eyebolt).
The ffive units I'm currently considering are the PerfectFlite HiAlt45K, Entacore AIM USB, Adept DDCS2, Perfectflite MAWDand Missile Works RRC-2. All are between 2.75" and 4.25" long.
I have two options for the coupler: use two connected Blue Tube couplers, 1.01" internal diameter and a total of 8" long, or BMS coupler tubing, any length that I choose and 0.977" (can be peeled a bit) internal diameter. Does it particularly matter which I use?
Or, would it be better to use 29mm tubing for the av-bay and attach the bulkheads to couplers, as seen here? That would give more room for the internal stuff, but be trickier to set up.
I'll be using one of the mini 6v or 12V camera batteries; how should I mount that in the altimeter bay?
First, an incredibly stupid question. Would it be possible to have the motor eject the drogue at apogee and then use a timer to eject the main? Perfectflite's staging electronics claim delays of 'at least 60 seconds' possible; even from 6000 feet, 45-50 seconds (from apogee) at 90-100 fps* will bring it down to 1500 feet or so.
* Yes, I know that's rather high for deploying the main, but this is a 10-ounce rocket with kevlar shock cords so it can survive it.
This is very appealing to me because the staging electronics are half the cost and size of the smallest dual-deploy altimeters, and I'd rather only deal with one ematch than two. However, because I can't know exactly how fast it will descend, it'll only be accurate to within around 500 feet or so of altitude, rather than knowing that the main will deploy exactly at 1000 feet or whatnot.
Second, how do I go about making such a tiny av-bay? I cannot use the standard design with a sled because the electronics are almost exactly the same width as the tube and thus must be centrally located. Also, the tiny bulkheads - 1" diameter - might not be able to hold three separate rods (two thread rods + eyebolt).
The ffive units I'm currently considering are the PerfectFlite HiAlt45K, Entacore AIM USB, Adept DDCS2, Perfectflite MAWDand Missile Works RRC-2. All are between 2.75" and 4.25" long.
I have two options for the coupler: use two connected Blue Tube couplers, 1.01" internal diameter and a total of 8" long, or BMS coupler tubing, any length that I choose and 0.977" (can be peeled a bit) internal diameter. Does it particularly matter which I use?
Or, would it be better to use 29mm tubing for the av-bay and attach the bulkheads to couplers, as seen here? That would give more room for the internal stuff, but be trickier to set up.
I'll be using one of the mini 6v or 12V camera batteries; how should I mount that in the altimeter bay?