18/20 RMS Question here.

Hi,

Need some help after the fact here. Launched a D13-7 reload, first attempt actually, in an Estes Nova Payloader. Had 6 launches on the ship previously and it was suffering from the Hibachi effect as the beautiful red paint job was bubbling. Winds were from the South at roughly 4-9 mph according to my wind meter. My field is at:

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doubles as a driving range. You see the white gravel area to the north that is the parking lot for the golfers and the driving stations are just to the south. If you look to the west and a little south, you will see a little black horizontal line which is a small parking area for about 4 cars for folks who fly R/C (and now rockets with me). My question has to do with the ejection charge as I couldn't figure it out with the instructions. I put the red cup over the end of the of the ejection chamber and crushed it and shook it. I was going to remove the cup but it seemed like there was alot of powder in there so I left it connected on the end of the engine. At a launch I went to in a May I asked a level 3 modeler, Pat Hibbs, if I could watch him do a reload. He told me to hop in his truck and he supervised his 13 year old nephew in doing an H reload. Pat had stated that one should crack the cap with the black powder and pour it into the well. He was emphatic that one should cover the well with a large piece of masking tape. In the 18/20 reload if one leaves the cap on, there is about a 1cm space between the powder in the bottom of the cap and the well on the bulkhead of the engine. Again I put the cap on the engine upright and squeezed the cap and shook the engine thinking I would get the powder into the well. I thought there might be too much powder and if I took the cap off the powder would fall out. I did not remove the cap and apply masking tape. When I saw the H reload, I distinctly remember that the black powder filled the well to the top before Pat had his nephew put the masking tape over it. He had a successful launch. All this is moot as I launched my model and my gosh, talk about noise! I've seen lots of other modelers' RMS loads G and higher go off but this little engine really roared. It sounded louder than the E30 and F23 SU motors I fired today too. Might be because I was closer to the launch pad but I was at the same distance when I did the SU's. Well the model went out of sight and never saw it again. Didn't hear an ejection charge fire although it could have been up so high I couldn't hear it. I did fire off a Quest Zenith II with a modified first stage I built from parts I had lying around. It was for a D12-0 booster instead of a B or C6-0. It shot up like the proverbial "bat out of hell", The sustainer is yellow and the booster is fluorescent orange. I saw it stage and then the sustainer went out of sight. I waited and waited and waited. I thought I had lost this model but I heard the streamer flapping in the air. I looked behind me and saw the last 200' descent of the sustainer land 150' behind me and not very far from the booster. I only mention this as it showed that a model might get so high one can't hear the ejection charge. (Or my hearing is bad.) Anyhow, appreciate any answers about my reloading technique and if anyone can point me to some websites that might have better instructions it would be most appreciated. Also lost an Eliminator on an E9-8 and a High Flier on a C6-7. Dang, my eyesight must be getting worse. I am unhappy with myself as I launched toward the south and it looks like I missed the range!! I mean look at the photo of the field. I still missed it OR I may have had recovery system failures in the Eliminator and High Flier. They were Estes stock, old and were made before I started using kevlar shock cords for everything. Put up a Super Nova Payloader and it separated from the body. Had one good flight on an E30 and then tried an F23 BJ engine. Saw the payload bay with parachute land way the heck to the north and west and went BEHIND a tree line. Too far for me to go and I have two of the Super Novas on the self with one still in kit form. There is some consolation there. TIA. Best regards, Kurt Savegnago

Reply to
Kurt
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You shouldn't need to crush it. Use a pick or a pair of needle nose pliers and pull out the white cap, if there's one in there, then snap it on, place the motor right side up, and tap it a few times.

The H loads don't come with caps, and there's no way to snap something onto the end of the closures. I think the cap is just a convenience in the hobby line (18mm, 24mm, 29/40-120) as opposed to the tape that we use on high power reloads.

It sounds to me like you did just fine in assembling your reload. If you're not sure, your best bet is to find someone locally who has used the same (or similar) reloads and have them watch you during the assembly process.

-Kevin

Reply to
Kevin Trojanowski

Hey Kevin,

Thanks for the advice. It looked to me that there was a wax covering in the ejection charge but I have two reloads left I can look at. Using a pick or needle nose pliers might have been a key point I missed out. I remember Pat breaking something and telling me "Not to use the cap". but I don't think that is a big deal. I think the answer I am looking for is that one is supposed to fill the well at the end of the engine with the BP ejection charge? I didn't mind losing the Nova Payloader as the BT was beginning to get cooked. I am saddened about losing the hardware though. Have a new engine on order. :) I was about to use the 18/20 in the Zenith II sustainer for a single stage flight. (Yes I know one can't use APCP engines in multi-staging like BP engines and need timers/igniters to do an air start) I had second thoughts about the Zenith because if I lost it, I would have two booster sections remaining. Am glad I chose the partially cooked N.P. for the flight.

Kurt Savegnago

Kev>

Reply to
Kurt

Kevin (and Kurt),

For the hobby RMS motors, the 'nozzle' red cap and the 'ejection charge' red cap are 'snapped together' to hold the ejection charge during shipment. In other words, there is no 'white cap' like there is on the HP stuff (which just has the nozzle cap, not the ejection cap).

I've found that the best way is to hold the ejection cap (the smaller of the two) with the opening up (obviously, unless you want to sprinkle the BP on your shoes), and then put the assembled motor on from the top -- then snap the cap into place. This should work perfectly, with no crushing. There is a lip on the ejection cap that should exactly be captured by the ejection end of the motor. Then, you're left with the nozzle cap to use to hold the igniter in place. Once the ejection cap has been snapped into place, you simply turn it over, and tap the side of the case to distribute the BP into the ejection well for good ignition.

It sounds as though everything was done correctly, except that you don't (shouldn't) be crushing the cap. The reason I suggest the above method, BTW, is to keep granules of the BP from getting 'stuck' in the lip area, which may be why yours didn't "snap" into place.

Side note: for folks who don't do the hobby reloads (doing HP only), this is a bit different than the method of pouring the BP into the well, then covering with the tape disc. I really wish the tape discs were just a little bit bigger, with just a little bit more adhesive. I found out the hard way (early on) that you MUST use masking tape on top of the disc, because those darn discs just DON'T stay in place. I prefer using the disc topped by a piece of masking tape, because using just the tape can sometimes leave minor gaps for the powder to leak out. I actually like the hobby method of using the plastic cap -- it is really simple, and pretty idiot proof (and I can be a pretty advanced idiot when I want to be)...

David Erbas-White

Reply to
David Erbas-White

To reiterate, HP reloads use a red cap that is ultimately used to cover the nozzle to 'package' the ejection charge. This is covered with a circular piece of paper that is bent into place to keep it there (but I don't need to tell you how often this DOESN'T work, and I end up with a reload kit filled with loose black powder). For the hobby reloads, the ejection charge is contained WITHIN two red caps -- the smaller one (IIRC) is used to go on the ejection end of the casing, and the larger one is used on the nozzle.

Don't confuse the white cardboard (bent/crimped) disc that HP guys remove (and throw away) with the way that the hobby RMS charges are supplied.

David Erbas-White

Reply to
David Erbas-White

Thanks; I couldn't remember if there was a white paper cap in there, or not -- it's been a while since I assembled a hobby reload.

-Kevin

Reply to
Kevin Trojanowski

This has been my experience too.

On the HP reloads, the disc sticking depends on weather you have grease or BP on the surface the disc has to stick to or not. Obviously if you are in the not catagory the disc sticks. I almost always need to use masking tape.

Reply to
Phil Stein

ANd I thought I was getting special limited edition motors. 8-)

Reply to
Phil Stein

That's a good problem to have :)

Reply to
Jerry Irvine

Interesting factiod.

Reply to
Jerry Irvine

I'm always very careful about making sure that no grease gets on the end of the closure, and 'tapping' it to get any of the grains of BP off the face, before putting the disc on. I also dry my hands carefully before handling the discs, and try to handle them just be the edges. Out of curiousity, I have occasionally touched the face of the discs to try and see how good the adhesive is. The discs just don't seem to have much (or very good) adhesive. I'm sure they're some kind of standard 'label', but I'm relatively sure they use the 'temporary' adhesive instead of a 'permanent' adhesive. In other words, I know that some address labels made by Avery are removable, and some aren't. This adhesives seems to be in the "aren't" category .

David Erbas-White

Reply to
David Erbas-White

I think I'm being careful - even when it doesn't stick. A piece of tape is good insurance.

Reply to
Phil Stein

I probably should have been clearer -- I ALWAYS put the masking tape on top of the white tape disc. I simply find that putting the disc on first (instead of using JUST masking tape) helps to keep the top end sealed.

David Erbas-White

Reply to
David Erbas-White

I put the little paper disk on and then tape it.....always.

Reply to
J.A. Michel

David Erbas-White wrote: I really wish the tape discs were

If you buy cards from a Hallmark store, they'll usually give you some "gold crown" stickers. Sometimes they'll give you some extras if you ask for them. They're supposed to be used as a fancy "seal" on the envelope but I think most people just throw them away. Anyway, they're bigger than the AT stickers, and have better adhesive. That's what I've been using for the past few years.

Reply to
raydunakin

And they messed up this BAR of a modeler!! Lost the rocket although I think it would have cooked through past the motor mount if I would have launched it a few more times with BP motors. I crushed the heck out of the end of the BP carrier and I suspect I didn't crack the danged paper properly. Am going to use a "pick" or some pointy device to get at the gal danged powder to pour into the ejection cup in the engine. I'll get the son of a buck to work ultimately!!!

Kurt Savegnago

Reply to
Kurt

Hey,

That is good advice but I still don't understand. I find I have a red cap with a cylindrical connector that is 1 to 1.5cm long. Am I supposed to rip off the cylindrical connector and pour the black powder into the well of the 18/20 engine amd then tape it over? After reading all the advice here, I'd like to stick a piece of APCP up Aerotechs' arse for their lousy, unclear instructions. They have all the O ring things right and easily understandable for me but the danged ejection charge is really funked up. I had a cool launch but I think the ejection never occurred as I just topped the ejection charge "cup" over the end of the engine. I never did find the "so-called" end cap for the igniter. Screw them as I just use tape with good results. Cripes there was over 1 to

1.5cm between the cup and the well of the engine and I didn't even know there was a paper or whatever barrier. Call me ignorant and I will eventually figure it out but the instructions suck and you can forward that to Aerotech.

Best regards, Kurt Savegnago

Reply to
Kurt

Hi,

Whaddya you use. A hammer to smash the thing in? In the reload kit of the D12-7W I have, there is at least 1.6cm of distance between the end of the alleged "collar" and the beginning or the ejection charge cup. From the end of the so called "cup" to where I can see BP is 2.5cm. That is way the heck too far for the smoke delay to ignite a charge through the paper. Tell me one thing. Am I supposed to smash, bash, screwup, hack, hit with a hammer and physically pour the BP into the end bulkhead of the

18/20 engine and tape it up? If so, I will find a way to get the galdanged powder out and Aerotech be damned.

Best regards, Kurt Savegnago

Phil Ste> >

Reply to
Kurt

Hi,

I did that and there was still 2cm from the cuff of the plastic cup to the ejection charge powder. Am I supposed to fracture, bend, scrape, screw up, macerate and pour the raw BP into the well? If that is the case, then I will do it with the replacement casing I have ordered. Even though I lost the model and it was getting to end of life, it was still a cool flight. Am I bitter? Just a little bit, although if AT sent me a replacement case that would be nice. (Although that wouldn't happen in a thousand years.)

Best regards, Kurt Savegnago

Reply to
Kurt

Go to this page:

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Click on the ejection charge video. If you still don't understand, post your SPECIFIC question here after viewing the video.

Note: while this is for the 29mm hobby case, the 18mm ejection charge assembly should work the same way.

David Erbas-White

Kurt wrote:

Reply to
David Erbas-White

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