38mm forward cap
- Thread starter qquake2k
- Start date
Help Support The Rocketry Forum:
cavecentral
Well-Known Member
- Joined
- Jul 1, 2011
- Messages
- 3,148
- Reaction score
- 38
I use them if available, otherwise, tape. Never had any issues. The little paper sticky discs that come with some reloads are pretty worthless. I toss those and use tape.
Eric
Well-Known Member
I use the Red Cap if I have it. But I only push it about half the way down. Because it feels very tight. I agree the paper discs never stick and use tape if I don't have the cap
- Joined
- Jul 15, 2015
- Messages
- 3,957
- Reaction score
- 2,718
I'm new to AT reloads this year, been flying CTI. I've burned 4 so far, the paper cap is almost a joke. I switched over to a piece of tape and then I put the cap on. Fits pretty snug, but I'm sure that the containment helps ensure a full burn. Also acts as an initial blast shield to keep any burning particles off of laundry.
rharshberger
Well-Known Member
I ditch the red caps and use masking tape instead, red caps can damage baffles after enough impacts, and its a piece of non-biodegradable plastic/trash thats difficult to find on the flying field.
Eric
Well-Known Member
I don't use any dog barf Under the Red Cap. It's on tight enough that the powder Burns very well in the confined area
GlueckAuf
Well-Known Member
I personally think the snugly-fitting red cap is the most secure, confidence-inspiring method of containing the ejection charge in a 38mm RMS motor, but it seems AT is leaving them out of at least some 38mm RMS reloads I've purchased lately in favor of those near-worthless, self-adhesive paper disks...and that's a shame.
On some of my larger air frames that require quite of bit of FFFFg to kick out the recovery gear--and more than the ejection charge well alone will hold--it's nice to put the empty cap on the table, measure and fill the cap with the requisite amount of BP, and then carefully press the inverted, assembled motor onto it. Stand it back up, shake the BP down into the touch hole, and then press the cap down a wee bit more to eliminate any cavity.
I use baffles (that can easily withstand the plastic cap's blow-off ballistics), so littering the rocket range with plastic isn't an issue. The cap falls out of the motor tube when I remove the spent motor. Often they're reusable, so I do.
If AT eventually eliminates those great red plastic caps in favor of the paper disks alone, then I reckon I'll drill a 1/2" or so hole in my remaining caps, clean them out, and then for each motor assembly I'll stick the provided paper disk to the INSIDE of one of the plastic caps before filling, and press the BP-filled cap onto the forward closure, just like I currently do. Hopefully that will allow me to reuse the remaining plastic caps indefinitely.
Good skies,
GlueckAuf
On some of my larger air frames that require quite of bit of FFFFg to kick out the recovery gear--and more than the ejection charge well alone will hold--it's nice to put the empty cap on the table, measure and fill the cap with the requisite amount of BP, and then carefully press the inverted, assembled motor onto it. Stand it back up, shake the BP down into the touch hole, and then press the cap down a wee bit more to eliminate any cavity.
I use baffles (that can easily withstand the plastic cap's blow-off ballistics), so littering the rocket range with plastic isn't an issue. The cap falls out of the motor tube when I remove the spent motor. Often they're reusable, so I do.
If AT eventually eliminates those great red plastic caps in favor of the paper disks alone, then I reckon I'll drill a 1/2" or so hole in my remaining caps, clean them out, and then for each motor assembly I'll stick the provided paper disk to the INSIDE of one of the plastic caps before filling, and press the BP-filled cap onto the forward closure, just like I currently do. Hopefully that will allow me to reuse the remaining plastic caps indefinitely.
Good skies,
GlueckAuf
I use them and like them. The caps are probably available separately from Caplugs through Grainger or McMaster.
caveduck
semi old rocketeer
- Joined
- Jun 6, 2011
- Messages
- 1,827
- Reaction score
- 585
The caplugs work great, though I share the concern about ejecting nondegradable material across your launch site. Like Steve said, extras are readily available and only cost a few cents each. There will not be any problems with them being too tight - confining the charge slightly will actually increase the energy considerably.
I agree the tape discs are utterly useless, AT should ditch them as they have so little holding power even if you keep the closure rim religiously clean. A fair number of novices crash their models by relying on the sticker discs so I discourage their use whenever I can.
Most of the time I use masking tape in the "X" pattern with a final wrap around the knurled side of the closure. And I definitely recommend packing some dogbarf on top if the well is not full. The powder has to be in contact with the delay grain to light it, and negative g's on deceleration *and* gravity + drag after apogee will both tend to pull it away. The physics is totally pro-failure after burnout, so better not to allow any room for the powder to migrate forward.
I agree the tape discs are utterly useless, AT should ditch them as they have so little holding power even if you keep the closure rim religiously clean. A fair number of novices crash their models by relying on the sticker discs so I discourage their use whenever I can.
Most of the time I use masking tape in the "X" pattern with a final wrap around the knurled side of the closure. And I definitely recommend packing some dogbarf on top if the well is not full. The powder has to be in contact with the delay grain to light it, and negative g's on deceleration *and* gravity + drag after apogee will both tend to pull it away. The physics is totally pro-failure after burnout, so better not to allow any room for the powder to migrate forward.
Similar threads
