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Model Forum / General / Rockets / April 2005[FFT] Plugging Estes or Quest BP motors
I know some motors come pre-plugged from the factory, ie A10-PT. But lets say I wanted a A10-6T which doesn't exist. Only an A10-3T is avilable. Let say just for the sake of illusion, that I create a small external plug that either fits within the top of the motor casing and/or sits right outside the end of the motor casing. This plug is not "glued" or adhere to the actual motor case in any way other than perhaps a friction fit, if the plug extended into the well of the motor casing. From my POV this is not "altering" the motor per se.... The plug itself is a temporary device designed basically to prevent the ejection charge already in the motor from going up into the actual body tube and pressurizing and ejecting the recovery system. It essentially acts as a bulkhead. Lets say for the sake of this illusion that I want to "plug" the motor and not use its "native delay train and ejection charge" due to the fact that there is only say a 3 sec delay avilable for use with this motor, and I want to use a microtimer based delay charge/ejctiion charge assembly in place of the actual motor delay train and ejection charge. If the motor is taped securing into the model body tube by use of tape, when the ejection charge fires at clay cap breakthrough, then I assume since the ejection charge gases cannot escape out the top of the motor, it will pressurize the now empty motor casing(except for residue )and be exhausted through the motor nozzle.... questions: Would you expect that the above would result in X amount of forward momentum? If I do this will it result in the motor nozzle being blown out due to the pressurization of the ejection charge? Could the pressurization be so much as to cause a paper motor casing failure due to temporary over pressurization? Somebody once posted the amounts by weight of actual BP in Estes motors...would somebody please post those amounts again? TIA shockie B) > If I do this will it result in the motor nozzle being blown out due to the > pressurization of the ejection charge? Yes. > Could the pressurization be so much as to cause a paper motor casing failure > due to temporary over pressurization? Yes.  SignatureJerry Irvine, Box 1242, Claremont, California 91711 USA Opinion, the whole thing. <mail to:01rocket@gte.net> Please bring common sense back to rocketry administration. (too late) Produce then publish. http://www.usrockets.com Ebay. http://tinyurl.com/6wlp8 jerry: are you sure or are you trying to feed me disinformation? If the ejection charge in Estes motors is lets say producing 15 lb/sq ft(?) of pressure, to eject the recovery system, surely the burn pressure on the casing and nozzle is way above 15 lb/sq ft? shockie B) >> If I do this will it result in the motor nozzle being blown out due to >> the [quoted text clipped - 7 lines] > > Yes. > jerry: are you sure or are you trying to feed me disinformation? Get a life. > If the > ejection charge in Estes motors is lets say producing 15 lb/sq ft(?) of [quoted text clipped - 14 lines] > > > > Yes. Or not. SignatureJerry Irvine, Box 1242, Claremont, California 91711 USA Opinion, the whole thing. <mail to:01rocket@gte.net> Please bring common sense back to rocketry administration. (too late) Produce then publish. http://www.usrockets.com Ebay. http://tinyurl.com/6wlp8 > jerry: are you sure or are you trying to feed me disinformation? If the > ejection charge in Estes motors is lets say producing 15 lb/sq ft(?) of > pressure, to eject the recovery system, surely the burn pressure on the > casing and nozzle is way above 15 lb/sq ft? When I have glued the forward section of the motor, it sounds like a shot gun blast and blows the nozzle out the rear end. >>jerry: are you sure or are you trying to feed me disinformation? If the >>ejection charge in Estes motors is lets say producing 15 lb/sq ft(?) of [quoted text clipped - 3 lines] > When I have glued the forward section of the motor, it sounds like a shot > gun blast and blows the nozzle out the rear end. That sounds cool :) was the rocket ok? > That sounds cool :) was the rocket ok? most of the time. once in decades , I had one blow the motor tube from a D13 , ouch ! almax: interesting.... what motors were you using? I am only really interested in a3 or a10 motors.... thanks shockie B) >> jerry: are you sure or are you trying to feed me disinformation? If the >> ejection charge in Estes motors is lets say producing 15 lb/sq ft(?) of [quoted text clipped - 3 lines] > When I have glued the forward section of the motor, it sounds like a shot > gun blast and blows the nozzle out the rear end. > almax: > > interesting.... > > what motors were you using? I am only really interested in a3 or a10 > motors.... D12s. A3s, same thing, but sounds like a 22 rim fire instead. b I know the answer to this one for certain as I have done it many many times. First, my experience. I own and fly a VB Li'l Wild Thing. The central motor is a standard 18mm Estes motor and the outer cluster consists of up to 6 13mm motors. The preferred motor for the cluster is the A10-0. To prevent hot gasses from burning the BT, you have to fill the top of the motor with epoxy. Now, A10-0s are getting as scarce as hen's teeth. So, I've tried two approaches. First, I plugged an A10-3. Each and every time it blows the case like a firecracker or it fires the plug foreword like a musket ball. neither option is any good. So, on to plan "B". In this option I scrape out the ejection charge leaving only a small amount of the delay train. Then I seal the top of the motor with epoxy. Works like a charm every time. SignatureR. J. Talley Teacher/James Madison Fellow NAR #69594 NRA #133073736 no need to waste A10-0s, look for Estes rocket car motors, A10-PT. they are plugged. > I know the answer to this one for certain as I have done it many many times. > First, my experience. I own and fly a VB Li'l Wild Thing. The central motor [quoted text clipped - 7 lines] > ejection charge leaving only a small amount of the delay train. Then I seal > the top of the motor with epoxy. Works like a charm every time. You are right of course, but when I bought the VB these motors were not yet on the market. SignatureR. J. Talley Teacher/James Madison Fellow NAR #69594 NRA #133073736 > I know the answer to this one for certain as I have done it many many times. > First, my experience. I own and fly a VB Li'l Wild Thing. The central motor [quoted text clipped - 7 lines] > ejection charge leaving only a small amount of the delay train. Then I seal > the top of the motor with epoxy. Works like a charm every time. Why don't you just buy the very available A10-P? Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD! <<< Kaplow Klips & Baffle: http://nira-rocketry.org/LeadingEdge/Phantom4000.pdf www.encompasserve.org/~kaplow_r/ www.nira-rocketry.org www.nar.org "I tell you, freedom and human rights in America are doomed. The U.S. government will lead the American people in and the West in general into an unbearable hell and a choking life." It wasn't available the last time I flew the bird in 2002. SignatureR. J. Talley Teacher/James Madison Fellow NAR #69594 NRA #133073736 An easy test would be to epoxy said engine into a 3/4" dead-end hole in a block of wood and test fire. Signature...The Bit Eimer NAR 84054 L1 "My goal in life is to be the kind of person my cat thinks he is" [remove keinewurst and reverse letters in domain to email me] -------------------------------------------------------------- >I know some motors come pre-plugged from the factory, ie A10-PT. But lets >say I wanted a A10-6T which doesn't exist. Only an A10-3T is avilable. [quoted text clipped - 40 lines] > > shockie B) > An easy test would be to epoxy said engine into a 3/4" dead-end hole in a > block of wood and test fire. And clearly fail. And also demonstrate this guy did NO real world tests before posting. SignatureJerry Irvine, Box 1242, Claremont, California 91711 USA Opinion, the whole thing. <mail to:01rocket@gte.net> Please bring common sense back to rocketry administration. (too late) Produce then publish. http://www.usrockets.com Ebay. http://tinyurl.com/6wlp8 who says you have to do real world test before posting? Is that a JI requirement in this group. The reason i asked was, why should i waste X amounts of motors testing them, if somebody has already done this successfully or not? shockie B) >> An easy test would be to epoxy said engine into a 3/4" dead-end hole in a >> block of wood and test fire. > > And clearly fail. > > And also demonstrate this guy did NO real world tests before posting. > who says you have to do real world test before posting? Not you. > Is that a JI observation? Yes. > requirement in this group. The reason i asked was, why should i waste X > amounts of motors testing them, To learn? > if somebody has already done this > successfully or not? Like me? But you would disregard that. :) > shockie B) > [quoted text clipped - 4 lines] > > > > And also demonstrate this guy did NO real world tests before posting. SignatureJerry Irvine, Box 1242, Claremont, California 91711 USA Opinion, the whole thing. <mail to:01rocket@gte.net> Please bring common sense back to rocketry administration. (too late) Produce then publish. http://www.usrockets.com Ebay. http://tinyurl.com/6wlp8 >who says you have to do real world test before posting? Is that a JI >requirement in this group. The reason i asked was, why should i waste X >amounts of motors testing them, if somebody has already done this >successfully or not? > >shockie B) What's the matter? Are you afraid you might learn something by doing it yourself? To cheap to buy a few motors? Because Jerry said so is the only reason I can come up with to not do it yourself and that shouldn't stop anyone.. > >who says you have to do real world test before posting? Is that a JI > >requirement in this group. The reason i asked was, why should i waste X [quoted text clipped - 5 lines] > What's the matter? Are you afraid you might learn something by doing > it yourself? To cheap to buy a few motors? Yes. > Because Jerry said so is the only reason I can come up with to not do > it yourself and that shouldn't stop anyone.. Point. SignatureJerry Irvine, Box 1242, Claremont, California 91711 USA Opinion, the whole thing. <mail to:01rocket@gte.net> Please bring common sense back to rocketry administration. (too late) Produce then publish. http://www.usrockets.com Ebay. http://tinyurl.com/6wlp8 >>An easy test would be to epoxy said engine into a 3/4" dead-end hole in a >>block of wood and test fire. > > And clearly fail. > > And also demonstrate this guy did NO real world tests before posting. And what "real world tests" did you do? >>>An easy test would be to epoxy said engine into a 3/4" dead-end hole in a >>>block of wood and test fire. [quoted text clipped - 4 lines] >> > And what "real world tests" did you do? The ones that resulted in his Big Fine. >I know some motors come pre-plugged from the factory, ie A10-PT. But lets >say I wanted a A10-6T which doesn't exist. Only an A10-3T is avilable. [quoted text clipped - 33 lines] > Could the pressurization be so much as to cause a paper motor casing > failure due to temporary over pressurization? Aren't you in more danger of blowing out your (Estes-type I would assume) body tube by doing this? Unless you can assure a gas-tight seal between the motor and plug, I think this could be a problem. Is kicking the motor an option? Would be far simpler, just block off the MMT with a bulkhead and loosely friction fit the motor. Another option would be to vent the gases, perhaps you could have a section of BT ahead of the motor with a simple baffle and small holes in the airframe to vent the gases evenly in all directions. My thoughts are that if you want to avoid modifying the motor, there may be more ways to skin the cat (or something like that ;) ). HTH. SignatureNiall Oswald ================================ http://www.bits.bris.ac.uk/niall UKRA 1345 EARS 1151 MARS > >I know some motors come pre-plugged from the factory, ie A10-PT. But lets > >say I wanted a A10-6T which doesn't exist. Only an A10-3T is avilable. -----snip----- > > Lets say for the sake of this illusion that I want to "plug" the motor and > > not use its "native delay train and ejection charge" due to the fact that > > there is only say a 3 sec delay avilable for use with this motor, and I > > want to use a microtimer based delay charge/ejctiion charge assembly in > > place of the actual motor delay train and ejection charge. -----snip----- > Is kicking the motor an option? Would be far simpler, just block off the MMT > with a bulkhead and loosely friction fit the motor. > > Another option would be to vent the gases, perhaps you could have a section > of BT ahead of the motor with a simple baffle and small holes in the > airframe to vent the gases evenly in all directions. I'm personally not a fan of motor ejection because I once had one actually hit my shoulder in a one-in-a-gazillion chance. Made me worry about lightning strikes, too. Two 1/4 in diameter vent holes 180 degrees apart below the solid bulkhead will vent the ejection charge nicely. John<==wearing hard hats at launches now > I'm personally not a fan of motor ejection because... Usually, ejecting motors is frowned upon. Most clubs use some type of farm land and motors can be a hazzard to livestock or machinery, so leaving motor liter all over the place from dozens of launches, isn't a good thing. I've flown them so that either way was an option, depending on the field and who I'm flying with. Some will say there is also a fire hazzaed but fire is more of a problem at liftoff, than from a fallen burned out booster. On the other hand, if these conditions are not an issue, a falling A-D type engine doesn't pose too much of a threat, they tend to tumble quite a bit and 999 times out of 1000, arch away from the launch area. To date, I've made over 50 flights where the engines ejected and never had a problem of any kind. I like the idea of lightening the chute load AND ejecting can make spent engine extraction easier. Ever had an engine get stuck in your favorite rocket? If you want to fly a bird that ejects it's engine, you can scotch tape a short piece of orange caution tape to it. That will allow you to track it as it falls and locate it later. Randy http://vernarockets.com/ john: I'm not sure venting the ejection charge gases is what I am after... I was hoping to use the ejection charge gases, whether it blows out the nozzle or not, as a secondary source of energy.... to get some additional altitude.... If I vent then I have potentially 2 problems: 1. the vented gases may cause some instability as it is exhausted.. 2. drag due to 2 holes in model.. I guess I might as well go ahead and give "the rest of the story".... Instead of using a microtimer as I posed in the 1st post, what I am actually considering doing is making my own delay train/ejection charge module.... and having the "real" ejection charge ignite the add-on delay train... I figure that I only need 3-4 more seconds to give me an actual 6-7 delay time... the idea is that with the A3-4T or A10-3T motors is their delay times are way too short for altitude.. I figure that a small delay/ejection charge module like this should not weight more than 2 grams max... and it would give me the effective 6-7 s delay time that I am looking for. shockie B) >> >I know some motors come pre-plugged from the factory, ie A10-PT. But >> >lets [quoted text clipped - 30 lines] > > John<==wearing hard hats at launches now > Instead of using a microtimer as I posed in the 1st post, what I am actually > considering doing is making my own delay train/ejection charge module.... [quoted text clipped - 11 lines] > > shockie B) Have you considered using a 1/4A3-3T as your delay/ejection module? If mounted inside the body tube the thrust will be inefective-old timers call that the Krushnic effect, there is a newer term that escapes me. It does weigh 5.6 grams though Dale Greene SPAAR 503 > john: > [quoted text clipped - 5 lines] > 1. the vented gases may cause some instability as it is exhausted.. > 2. drag due to 2 holes in model.. In that case, use a solid bulkhead and very positive motor retention because the motor't ejection charge is going to go off just like the firecracker it is. Just remember you are gambling that the nozzle clay is the weak point...what if the nozzle is stronger than your BT at the motor / bulkhead interface ? > I guess I might as well go ahead and give "the rest of the story".... > > Instead of using a microtimer as I posed in the 1st post, what I am actually > considering doing is making my own delay train/ejection charge module.... > and having the "real" ejection charge ignite the add-on delay train... Don't think that's going to work very well because the ejection charge goes off in a very short timeline, and probably will have a hard time igniting a delay composition on its own. Good luck which ever way you decide to go. I know I have frequently designed myself into a trap when I discover my rocket can't be completed without adding some 'unobtainium' to the airframe. John<==been there, got the unfinished rockets to prove it > I figure that I only need 3-4 more seconds to give me an actual 6-7 delay > time... [quoted text clipped - 42 lines] > > > > John<==wearing hard hats at launches now This had got to be one of the most crazy ideas I've seen on RMR in years. The ejection charge will still fire, and the "plug" will just be fired into the internals of the bird. (friction fit?) If you don't want an ejection charge, you got ways to correct for it: 1) buy the motor you really need 2) vent it's charge 3) talk to Gary and get him to issue a press release that none of the testing groups have approved as to "motor modifications". (gary might do it, even though it's BP! He wants sales and happy people....) 4) put the bird on the shelf, as it can longer be flown. What if I had a bird that used the "short" motors from Estes? (the original Midget comes to mind...) is it Ok for me to cut the casing to the proper length? (heck, it's only cardboard I'm cutting!!) What happens if I make the 6pm news when doing this, as a spark hit the ejection charge? (Model Rocket motor and bandsaw burns down house, more at 11!) > I know some motors come pre-plugged from the factory, ie A10-PT. But lets > say I wanted a A10-6T which doesn't exist. Only an A10-3T is avilable. [quoted text clipped - 39 lines] > > shockie B) >3) talk to Gary and get him to issue a press release that none of the >testing groups have approved as to "motor modifications". (gary might do it, >even though it's BP! He wants sales and happy people....) > > > For the first time (to the best of my recollection) in all my years on rmr, I'm turning the flamethrower on full blast. Woody, pull your head out of your butt. The rules regarding manufacturer recommended modifications has been on the books for eons. The entire POINT of modifications needed manufacturer recommendations is to allow for 'minor' tweaks that may (or may not) have been fully covered in other material and/or instructions, to allow for either safe operation or a wider range of operation. If, at any point, a manufacturer ABUSES that privilege, the certification organizations would theoretically have the right to ask for corrective action -- which might take the term of a request for clarification, a request for recertification, etc. The entire POINT of this is that the manfacturer is the one who's butt is on the line in relation to liability issues, so they are very unlikely to 'recommend' modification that might create greater risk or liability. Just because you've got a hair up your tail about this is no reason to jump on Gary -- he's done what the vast majority of Aerotech composite motors have been asking for for years -- and done it in a very thorough and professional manner. To suggest that what Gary has done in relation to delay charge modifications is on par with folks 'experimenting' with plugging BP motors with epoxy suggests that you don't have clue one as to what is going on. In the case of delay modification, we have a situation that has been in place for quite some time with other manufacturers, that has no record of any problems, being made 'legal'. In the case of BP motor plugging, all of the folks who have done it are saying DON'T do it, because it's dangerous. For you to imply that what Gary did was in any way similar is unconscionable. I look forward to hearing your apology (but I won't hold my breath)... David Erbas-White > >3) talk to Gary and get him to issue a press release that none of the > >testing groups have approved as to "motor modifications". (gary might do it, [quoted text clipped - 14 lines] > to allow for either safe operation or a wider range of operation. If, > at any point, a manufacturer ABUSES that privilege, The problem being real or perceived. Gary is given wide discretion while others are harassed and expensed to death. > the certification > organizations would theoretically have the right to ask for corrective [quoted text clipped - 5 lines] > unlikely to 'recommend' modification that might create greater risk or > liability. That was not the position taken on Kosdon Or USR or Vulcan or ACS ... And these all had paperwork, so that excuse evaporates. There is an OUTSTANDING problem. Different treatments of different vendors. Aerotech was given a pass. You and I agreee it was a good one. Fine. But CTI was not given the same pass on the same issue. Fact. That fact is going to result in bad vibes from the "excluded class" while some revel in the ability to modify their monopoly sourced errortech motors. Jerry > Just because you've got a hair up your tail about this is no reason to > jump on Gary -- he's done what the vast majority of Aerotech composite [quoted text clipped - 14 lines] > > David Erbas-White SignatureJerry Irvine, Box 1242, Claremont, California 91711 USA Opinion, the whole thing. <mail to:01rocket@gte.net> Please bring common sense back to rocketry administration. (too late) Produce then publish. http://www.usrockets.com Ebay. http://tinyurl.com/6wlp8 >There is an OUTSTANDING problem. Different treatments of different >vendors. [quoted text clipped - 7 lines] >Jerry > Should CTI have been given a pass on this? Frankly, yes! But, Gary did the SMART thing as a businessman -- he let somebody else blaze the trail and take the arrows, and once there was more history for it, he approved it for his own product. This, Jerry, is known as "conservative business practice". David Erbas-White I apologize for the fact that you with born without an understanding of sarcasm! Has S&T said anything new? Last I heard, was S&T was still looking at it (per John) > >3) talk to Gary and get him to issue a press release that none of the > >testing groups have approved as to "motor modifications". (gary might do it, > >even though it's BP! He wants sales and happy people....) > For the first time (to the best of my recollection) in all my years on > rmr, I'm turning the flamethrower on full blast. > To suggest that what Gary has done in relation to delay charge > modifications is on par with folks 'experimenting' with plugging BP > motors with epoxy suggests that you don't have clue one as to what is > going on What about the good old Ellis J350 mods? "Hey users, we got a problem and the way to fix it is to drill out the hole in the grain to 1/2"!" This was a mod that should have required a recert, as the J350 was no longer a J350! Hey, the Ellis J350 was one case, and the "red delay liner" was another...... >In the case of delay modification, we have a situation that > has been in place for quite some time with other manufacturers, that has > no record of any problems, being made 'legal' And also required 3 certs of each delay grain, with various "adjusted" delays. And the tool to be modified to alow a finite number of adjustments. > 3) talk to Gary and get him to issue a press release that none of the > testing groups have approved as to "motor modifications". (gary might do it, > even though it's BP! He wants sales and happy people....) Don't forget to say NAR and TRA will go along with teflon-Gary on issues others have been refused over. - Multiple subcontractors - modifications of already certified motors. - field modifications of primary propelling charges - to overcome and prevent recall of known manufacturing defects Jerry SignatureJerry Irvine, Box 1242, Claremont, California 91711 USA Opinion, the whole thing. <mail to:01rocket@gte.net> Please bring common sense back to rocketry administration. (too late) Produce then publish. http://www.usrockets.com Ebay. http://tinyurl.com/6wlp8 >>3) talk to Gary and get him to issue a press release that none of the >>testing groups have approved as to "motor modifications". (gary might do it, [quoted text clipped - 9 lines] > > Jerry Poor pathetic psychotic jerry. AZ: thanks for telling me this idea is crazy! Anyway, the ejection charge from the A3-4T motor would indeed "fire", with the idea that above the motor, a delay and ejection charge module of my own making. The idea is the hot particulate of the ejection charge will ignite this delay/ejection charge module. The module will not be blown upwards into the model, as there is a bulkhead above it.....the idea is to get 2-3 extra seconds of delay time so that my A3-4T functions like an A3-6/7-T.. the secondary ejection charge would then pop out the recovery system. There are NO modifications or alterations made to the actual original A3-4T motor. I may have to add some exhaust holes to help relieve the pressure and I may have to place the forward bulkhead up an inch or two of the delay/ejection charge module, so that the ejection charge pushes the delay/ejection charge module up these 2 inches and allows more space to pressurize to prevent nozzle blowout or a rupture of the casing.... shockie B) > This had got to be one of the most crazy ideas I've seen on RMR in years. > [quoted text clipped - 76 lines] >> >> shockie B) > What if I had a bird that used the "short" motors from Estes? (the original > Midget comes to mind...) is it Ok for me to cut the casing to the proper > length? (heck, it's only cardboard I'm cutting!!) What happens if I make > the 6pm news when doing this, as a spark hit the ejection charge? (Model > Rocket motor and bandsaw burns down house, more at 11!) No, it's not "OK" to make your own short motors by sawing off an inch of empty casing. What I *HAVE* done many times, its take a used casing, saw it down, clean it out, and insert a "T" motor inside it. A standard 18mm casing makes a perfect adapter for them. And a shortened as above 18mm casing makes a perfect Shorty motor. And a cleaned out used D12 casing makes a perfect 18->24mm adapter. I just used one this weekend. Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD! <<< Kaplow Klips & Baffle: http://nira-rocketry.org/LeadingEdge/Phantom4000.pdf www.encompasserve.org/~kaplow_r/ www.nira-rocketry.org www.nar.org It had become an universal and almost uncontroverted position in the several States, that the purposes of society do not require a surrender of all our rights to our ordinary governors; that there are certain portions of right not necessary to enable them to carry on an effective government, and which experience has nevertheless proved they will be constantly encroaching on, if submitted to them; that there are also certain fences which experience has proved peculiarly efficacious against wrong, and rarely obstructive of right, which yet the governing powers have ever shown a disposition to weaken and remove. Of the first kind, for instance, is freedom of religion; of the second, trial by jury, habeas corpus laws, free presses. -- Thomas Jefferson -----snip----- > No, it's not "OK" to make your own short motors by sawing off an inch of > empty casing. What I *HAVE* done many times, its take a used casing, saw it > down, clean it out, and insert a "T" motor inside it. A standard 18mm casing > makes a perfect adapter for them. And a shortened as above 18mm casing makes > a perfect Shorty motor. And a cleaned out used D12 casing makes a perfect > 18->24mm adapter. I just used one this weekend. And a cleaned out used D12 casing sawn into 1/4 in rings makes nifty spacers to hold an 18mm motor without adding excessive weight in the tail of the bird. John<==if I glue the rings on, have I 'modified' the C6 ? http://nar.org/SandT/releases/r63.html > John<==if I glue the rings on, have I 'modified' the C6 ? according to NAR S&T you have NOT modified the motor... shockie B) >> In article <MP%8e.54$7I2.11180@news.uswest.net>, "AZ Woody" > <Reply@here.not.email> writes: [quoted text clipped - 17 lines] > > John<==if I glue the rings on, have I 'modified' the C6 ? Oh, now that's interesting. I have 2 Midgets from my pre-BAR days on the shelf which I've always intended to fly with "Kaplow adapters" (the 18mm casings). But maybe glueing 18mm casing rings on would be better as it would simplify doing the staging connection between the two Ts. Signature...The Bit Eimer NAR 84054 L1 "My goal in life is to be the kind of person my cat thinks he is" [remove keinewurst and reverse letters in domain to email me] -------------------------------------------------------------- > >> In article <MP%8e.54$7I2.11180@news.uswest.net>, "AZ Woody" > > <Reply@here.not.email> writes: [quoted text clipped - 22 lines] > casings). But maybe glueing 18mm casing rings on would be better as it > would simplify doing the staging connection between the two Ts. Do not build/modify them. Save them. Clone them. Jerry Also, I don't recall Jerry ever attacking the concept of national rocketry organizations, just ineffective and corrupt leadership, a HUGE difference." - Jim Rutkowski, Executive Chef, www.TrailerTrashAerospace.com SignatureJerry Irvine, Box 1242, Claremont, California 91711 USA Opinion, the whole thing. <mail to:01rocket@gte.net> Please bring common sense back to rocketry administration. (too late) Produce then publish. http://www.usrockets.com Ebay. http://tinyurl.com/6wlp8 <snip> >> Oh, now that's interesting. I have 2 Midgets from my pre-BAR days on the >> shelf which I've always intended to fly with "Kaplow adapters" (the 18mm [quoted text clipped - 4 lines] > > Clone them. Too late - they were built about 35 years ago. Of course I won't modify them - that's why I think glueing the 18mm centering rings onto the T motors is a good idea. Signature...The Bit Eimer NAR 84054 L1 "My goal in life is to be the kind of person my cat thinks he is" [remove keinewurst and reverse letters in domain to email me] -------------------------------------------------------------- > Of course I won't modify [my 35yo Midgets]... that's why I think glueing the 18mm > centering rings onto the T motors is a good idea. Bit, I fly lots of Midgets. I think you'll find, with the original K-40, that trying to using rings instead of a full-length 1.75" sleeve (of spent casing) is more trouble than it's worth. Just put the T booster in a spent casing without cutting it into rings. We're talking maybe 5 grams of difference. Not enough to be worth the effort. Also, you'll find the motor cases aren't perfectly round and centered, or exactly the right size. You'll be more likely to get a mis-aligned (canted) motor using two rings than using a full length sleeve. For the sustainer, the pickin's are pretty slim. Either a 1/2A3-4T (sleeved) or a sawed-off A8-5. Here's a couple of my latest incarnations. This one is nearly an exact clone, but I lengthened the booster a tad to accomodate more sustainer motor overhang, to ensure straighter coupling. http://home.flash.net/~samily/midget-new-k-40/ Here's a slight upscale using Quest T-30. Uses full sized, standard 18mm motors. No sleeves or saws required :) http://home.flash.net/~samily/midgetT30/ http://home.flash.net/~samily/midgetT30/Quidget6-2.JPG BTW, I got some pyrogen. This weekend, I plan to put to use the research you did on staging with pyrogen. Doug >> Of course I won't modify [my 35yo Midgets]... that's why I think glueing >> the 18mm [quoted text clipped - 29 lines] > BTW, I got some pyrogen. This weekend, I plan to put to use the > research you did on staging with pyrogen. Very nice Midgets and great paint as well. OK, so the 18mm rings are not the right way to go, huh? Oh, well. I just figured it was going to be kind of a pain to friction fit both the Ts into the 18mm adapters and then the 18mm adapters into the BTs, meanwhile trying to keep the 2 T's properly connected for staging. Of course, I guess I could just glue the adapters to the Ts, turning them into 18mm motors, and stage them as such. Just means I have to cut new adapters for each launch. I know A10-0Ts are OOP - but it looks like they're no longer certed. Stupid... (I think once certed, they should stay certed - at least for sport launching - unless there's a "recall"). Hey! didn't think anyone was listening to my machinations about pyrogen-coated nozzles. :^) I'll certainly be interested to hear about your experiences. What pyrogen did you get? I used Magnelite. Recently ordered a bunch of powdered metals and other such goodies so that I can get some experience with pyrogen and igniters. Signature...The Bit Eimer NAR 84054 L1 "My goal in life is to be the kind of person my cat thinks he is" [remove keinewurst and reverse letters in domain to email me] -------------------------------------------------------------- > Very nice Midgets and great paint as well. Thanks. I spend too much time sanding and painting. > OK, so the 18mm rings are not the right way to go, huh? Oh, well. I've tried using motor cases to cut engine blocks from, but the rings are usually too small, and need to be built up (few wraps of tape) before they fit well. It was easier to just use real centering rings. (Of course, if it's two in the morning, and you're out, then the spent cases are a God-send :) In trying to use these sawn rings as adaptors, I'm afraid you will find yourself building up the motors to fit snugly in them, then building the rings up on the outside to fit in the motor tubes, then getting frustrated with all the effort required. Sawing off the case at 1.75" and sliding the T motor is a lot easier (IMHO). Buzz McDermott gave me some original ~1972 adaptors which look like unused motor cases, but include engine hooks, on the inside IIRC. The hooks are flush with the ends. Basically, they turn T motors into S motors, but are reusable. Of course, the adaptors still need to be friction fit into the motor tubes. I haven't gotten around to playing with them yet... FWIW, these variants just use the T motors as is, without adaptors: http://home.flash.net/~samily/stridget/#new-tridget http://home.flash.net/~samily/midget-K-40/ That's the easiest way :) > I just figured it was going to be kind of a pain to friction fit both the Ts > into the 18mm adapters and then the 18mm adapters into the BTs, meanwhile > trying to keep the 2 T's properly connected for staging. Of course, I guess > I could just glue the adapters to the Ts, turning them into 18mm motors, and > stage them as such. Just means I have to cut new adapters for each launch. That's the tradeoff. Either make the extra effort to cut new ones each time or make the effort to friction fit the T's into the adaptors. It helps to just cut a bunch at once and put them in your range box so you always have one. Also, if the motor slides in and seems to stick well without tape or glue, then you can maybe reuse that one. In fact, using these adaptors, I just made up a bunch of syntho-S motors and put them in my range box, right next to my few genuine S motors. > I know A10-0Ts are OOP - but it looks like they're no longer certed. > Stupid... (I think once certed, they should stay certed - at least for > sport launching - unless there's a "recall"). Don't get me started. > Hey! didn't think anyone was listening to my machinations about > pyrogen-coated nozzles. :^) I'll certainly be interested to hear about > your experiences. What pyrogen did you get? I used Magnelite. I got some from a friend. I'm not sure he's licensed to sell pyrogen, so I won't mention his name, JIC. > Recently ordered a bunch of powdered metals and other such goodies so that I > can get some experience with pyrogen and igniters. I'm already spread too thin with the hobby, without adding yet another aspect of it. But I'd like to play with it someday. My latest idea is to see if I can put an Aerotech delay into an Estes booster motor and see if the delay will light when the BP burns thru. We could make our own oddball motors that way. C6-1 D12-14 B6-9 And it's no more involved (read: dangerous) than assembling a 24mm reload. Doug >> Very nice Midgets and great paint as well. > > Thanks. I spend too much time sanding and painting. Me too, but at least you get a decent results! I just get the same ol' same ol'... <snip> > Buzz McDermott gave me some original ~1972 adaptors which look > like unused motor cases, but include engine hooks, on the inside > IIRC. The hooks are flush with the ends. Basically, they turn T > motors into S motors, but are reusable. Of course, the adaptors > still need to be friction fit into the motor tubes. I haven't > gotten around to playing with them yet... Flush with the end? Allowing one to be used in the sustainer and still permit non-gapped staging? > FWIW, these variants just use the T motors as is, without > adaptors: > http://home.flash.net/~samily/stridget/#new-tridget > http://home.flash.net/~samily/midget-K-40/ This is just getting out of hand!!! :^) <snip> >> I know A10-0Ts are OOP - but it looks like they're no longer certed. >> Stupid... (I think once certed, they should stay certed - at least for >> sport launching - unless there's a "recall"). > > Don't get me started. sounds like you feel the same way - and a lot of others on rmr I still haven't heard any good justification for the way things are - just "that's the way its always been" >> Hey! didn't think anyone was listening to my machinations about >> pyrogen-coated nozzles. :^) I'll certainly be interested to hear about >> your experiences. What pyrogen did you get? I used Magnelite. > > I got some from a friend. I'm not sure he's licensed to sell > pyrogen, so I won't mention his name, JIC. Well, he obviously didn't "sell" it to you, did he? that's why he's your friend. Do you know what his 'gen is based on? (or is that a trade secret?) >> Recently ordered a bunch of powdered metals and other such goodies so >> that I >> can get some experience with pyrogen and igniters. > > I'm already spread too thin with the hobby, without adding yet another > aspect of it. But I'd like to play with it someday. Its spreading all that paint that spreads you too thin. Fly naked! Signature...The Bit Eimer NAR 84054 L1 "My goal in life is to be the kind of person my cat thinks he is" [remove keinewurst and reverse letters in domain to email me] -------------------------------------------------------------- > Flush with the end? Allowing one to be used in the sustainer and still > permit non-gapped staging? I got one out. Pic and scans here: http://home.flash.net/~samily/13mm-adaptor/ Looks like it's best for single stage, but could be used for staging. The hook is flush, but on the outside contrary to what I said earlier. The user must cut a shallow slot for it to fit in. Basically, the challenge will be dealing with the ends of the hooks where the two adaptors (booster and sustainer) come together. Might want to grind a bit of relief in the end of each adaptor case so the hook ends are flush into the end of the mating cases. > This is just getting out of hand!!! :^) Did you see this? <vbg> http://home.flash.net/~samily/midgets/ (There are 5 newer ones not shown. And the 6-inch is in lawn dart heaven.) > sounds like you feel the same way - and a lot of others on rmr > I still haven't heard any good justification for the way things are - just > "that's the way its always been" Basically, I look at it like this: They could have just said "no motors over 3 years old" period. But they allow us to fly older ones because they don't check the date if they're on the approved (still in production) list. Still, I have over 100 A10-0T's in my stash. Gonna take a while to whittle that down at non-sanctioned launches. > Do you know what his 'gen is based on? (or is that a trade secret?) I didn't ask. I'm an electrical engineer - I'm supposed to know a little chemistry - but my pyro chemistry knowledge is embarassingly lame. Basically, it's some gray stuff with acetone :) > Its spreading all that paint that spreads you too thin. Fly naked! That'd put a serious imbalance in my mojo :) Doug >> Flush with the end? Allowing one to be used in the sustainer and still >> permit non-gapped staging? > > I got one out. Pic and scans here: > http://home.flash.net/~samily/13mm-adaptor/ Ah, looks interesting. Gives me some ideas for something similar, but with the hook embedded on the inside of an 18mm casing. > Basically, I look at it like this: They could have just said "no motors > over 3 years old" period. But they allow us to fly older ones because > they don't check the date if they're on the approved (still in production) > list. Still, I have over 100 A10-0T's in my stash. Gonna take a while to > whittle that down at non-sanctioned launches. I just ordered 10 packs (40). >> Do you know what his 'gen is based on? (or is that a trade secret?) > > I didn't ask. I'm an electrical engineer - I'm supposed to know a little > chemistry - but my pyro chemistry knowledge is embarassingly lame. > Basically, it's some gray stuff with acetone :) I'm a EE too, though only <15 volts if I can help it. :^) But we're only talking alchemy here, how difficult can it be?! <grin> Signature...The Bit Eimer NAR 84054 L1 "My goal in life is to be the kind of person my cat thinks he is" [remove keinewurst and reverse letters in domain to email me] -------------------------------------------------------------- <snip> > Basically, I look at it like this: They could have just said "no motors > over 3 years old" period. [quoted text clipped - 3 lines] > Gonna take a while to > whittle that down at non-sanctioned launches. I just received an order of 40 A10-0Ts, which brings my stock up to 50+. Of course, since they aren't certed, they must be dangerous so I can't fly them. :( Signature...The Bit Eimer NAR 84054 L1 "My goal in life is to be the kind of person my cat thinks he is" [remove keinewurst and reverse letters in domain to email me] -------------------------------------------------------------- > I just received an order of 40 A10-0Ts, which brings my stock up to 50+. > Of course, since they aren't certed, they must be dangerous so I can't fly > them. :( Correct. If you forget this obvious fact, be sure to repeat the NAR/TRA mantra continuously until your "bad attitude" changes. "Just fly rockets." - Bruce Kelly Except uncertified motors. :) SignatureJerry Irvine, Box 1242, Claremont, California 91711 USA Opinion, the whole thing. <mail to:01rocket@gte.net> Please bring common sense back to rocketry administration. (too late) Produce then publish. http://www.usrockets.com Ebay. http://tinyurl.com/6wlp8 > For the sustainer, the pickin's are pretty slim. Either a 1/2A3-4T > (sleeved) or a sawed-off A8-5. Pickens are even slimmer for the booster now that the A10-0T is history :-( Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD! <<< Kaplow Klips & Baffle: http://nira-rocketry.org/LeadingEdge/Phantom4000.pdf www.encompasserve.org/~kaplow_r/ www.nira-rocketry.org www.nar.org It had become an universal and almost uncontroverted position in the several States, that the purposes of society do not require a surrender of all our rights to our ordinary governors; that there are certain portions of right not necessary to enable them to carry on an effective government, and which experience has nevertheless proved they will be constantly encroaching on, if submitted to them; that there are also certain fences which experience has proved peculiarly efficacious against wrong, and rarely obstructive of right, which yet the governing powers have ever shown a disposition to weaken and remove. Of the first kind, for instance, is freedom of religion; of the second, trial by jury, habeas corpus laws, free presses. -- Thomas Jefferson > What if I had a bird that used the "short" motors from Estes? (the original > Midget comes to mind...) is it Ok for me to cut the casing to the proper > length? (heck, it's only cardboard I'm cutting!!) What happens if I make > the 6pm news when doing this, as a spark hit the ejection charge? (Model > Rocket motor and bandsaw burns down house, more at 11!) You should use a tubing cutter for that, not the bandsaw! -dave w Even so, would it be a valid mod per NAT/TRA? Doubt it..... > > What if I had a bird that used the "short" motors from Estes? (the original > > Midget comes to mind...) is it Ok for me to cut the casing to the proper [quoted text clipped - 5 lines] > > -dave w > Even so, would it be a valid mod per NAT/TRA? Doubt it..... No. Only praxctical and safe. Jerry "Wrong. You don't get to decide the cert/decert rules. That's for the certifying authority to decide." - Ray Dunakin > > > What if I had a bird that used the "short" motors from Estes? (the > original [quoted text clipped - 7 lines] > > > > -dave w SignatureJerry Irvine, Box 1242, Claremont, California 91711 USA Opinion, the whole thing. <mail to:01rocket@gte.net> Please bring common sense back to rocketry administration. (too late) Produce then publish. http://www.usrockets.com Ebay. http://tinyurl.com/6wlp8 |
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