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Model Forum / General / Rockets / October 2006Should I be thinking about Hybrid?
Hi Everyone, I got my L1 cert at the October skies, TCC launch last weekend, and I am worried about the fate of amateur rocketry from current trends in overzealous regulation. I am at a point where I haven't yet invested in too much motor hardware and I am wondering if I should just make the switch to hybrid now to avoid this misguided overregulation by the ATF. I don't live in a place where an LEUP is possible and it seems that going hybrid is a reasonable alternative. I didn't have a lot of time to wander around at the launch, but I didn't hear of anyone using hybrid. Are any of you using hybrid? Why is it not more accepted by the HPR community as a whole? > Hi Everyone, > I got my L1 cert at the October skies, TCC launch last weekend, and I [quoted text clipped - 7 lines] > hybrid. Are any of you using hybrid? Why is it not more accepted by > the HPR community as a whole? All of my HP flights are hybrid flights, not so much because of the regulatory picture as the "quirky complexity" of hybrids in general. There is a steep cost and learning curve with hybrids, and I think this deters a lot of folks from becoming involved. Also, each flight requires electronic deployment, so added expense, prep time, and complexity. There are also some realities working with hybrids: the motor case are LONG, and require rockets that can handle them (I scratch build everything, except a Flis Richter Recker that I'm bashing for 29mm hybrids). The mass fraction is not as favorable as APCP, nor is the ISP as high. They are, however, capable of some decent performance, especially the newer crop of monotube motors. I posted a blurb in alt.binaries.models.rockets about the cost of GSE and the cost per flight. The conclusion I've come to is that if you are going to fly a lot, hybrids are not only cost effective but cheaper than AP motors, though it takes a while to 'break even' on the GSE. The cost, however, was not a prime issue for me... a couple years back when I BAR I was surfing the web when I came across a video of a hybrid rocket on the pad, filling and then venting before launch... I was hooked! It's only gotten worse since then, and both clustered and staged hybrids are on my slate for next summer. Why are hybrids not more accepted? Cost, complexity, and a steep learning curve are factors. Very few dealers support hybrid products. A perception that hybrid motors are "wimpy". Few experienced gas-passers to mentor new hybrid flyers. I think it's the complexity that puts most people off; I frequently hear comments like "I could prep and fly four rockets in the time it takes you to prep one." Although more and more lately I'm hearing "THAT was a hybrid?!?!?" LOL-- I chalk that up to my increasing experience and the J642 motor I recently launched :) Kevin OClassen NAR 13578 TRA 10569 > I posted a blurb in alt.binaries.models.rockets about the cost of GSE and > the cost per flight. The conclusion I've come to is that if you are going > to > fly a lot, hybrids are not only cost effective but cheaper than AP motors, > though it takes a while to 'break even' on the GSE. After I wrote this, I set up an excel spreadsheet that broke down the costs per flight of the hybrid motors I've flown, the cost of a (generally) comparable AP reload, and the number of flights I made this year. To my surprise I appear to have saved $475 over 31 flights.... Reinforces what I thought was true, that enough flights makes owning the GSE (cost ~$600) worth it. "Enough" is fewer than I thought, however... I was thinking on the order of 100 flights. Kevin OClassen The cost difference scales with the motor size. M motor hybrids can save $100 or more per flight (not including GSE amortization). To me hybrids are just another aspect of the hobby that I enjoy. I fly both APCP and Hybrids. > After I wrote this, I set up an excel spreadsheet that broke down the > costs per flight of the hybrid motors I've flown, the cost of a [quoted text clipped - 7 lines] > > Kevin OClassen Thanks all, What do you think the startup cost will be for some H and I impulse flights? Also, I intend to take this hybrid to level 2 or 3 eventually, so do I need different launch support for each level. By launch support I am talking tanks, regulators, ignition source etc? Is there a good tutorial on the subject? Also, other than longer motor tube, what other considerations are necessary for rocket construction? I appreciate Glen's comments because I did ask why hybrids weren't more common in the rocketry groups. And Glen's answer actually is encouraging since I thought there might be valid concerns, but if the only problem is that they don't make enough noise or smoke well....whatever. > > Hi Everyone, > > I got my L1 cert at the October skies, TCC launch last weekend, and I [quoted text clipped - 42 lines] > NAR 13578 > TRA 10569 http://www.pratthobbies.com/info_pages/getting_started.htm good place to start. As with APCP, different motors have different properties. The WestCoast I110 has a nice blend of smoke and noise. The RATTworks K240 has a unique sound and visuals. As do the Hyperteks. > Thanks all, > What do you think the startup cost will be for some H and I impulse [quoted text clipped - 8 lines] > only problem is that they don't make enough noise or smoke > well....whatever. Tanks and regulators are the same for everything. Pratthobbies.com has a modular system that can be modified and expanded to work with most hybrid systems. Doug Pratt is a great source of knowledge and products for hybrids. Phil >What do you think the startup cost will be for some H and I impulse >flights? Also, I intend to take this hybrid to level 2 or 3 [quoted text clipped - 7 lines] >only problem is that they don't make enough noise or smoke >well....whatever. >Hi Everyone, >I got my L1 cert at the October skies, TCC launch last weekend, and I [quoted text clipped - 7 lines] >hybrid. Are any of you using hybrid? Why is it not more accepted by >the HPR community as a whole? Congratulations! For hybrids or a LEUP, I suggest that you check with your club to see what resources are available. By that I mean see if someone is willing to provide contingency storage and see if they have GSE. Once you've checked into it, go from there. Phil > Hi Everyone, > I got my L1 cert at the October skies, TCC launch last weekend, and I [quoted text clipped - 7 lines] > hybrid. Are any of you using hybrid? Why is it not more accepted by > the HPR community as a whole? Our club has a full GSE but due to it's age, we've had a lot of failed launches which turned people off to the idea of Hybrids.. that seems to be the norm in the past if they've had them and things have gotten much easier nowadays.. Doug Pratt from Pratthobbies (www.pratthobbies.com) seems to be the go-2-guy when it comes to the in's and out's of hybrids for any specific questions.. I'm currently picking up a RATT works setup to get everything working.. To have the casings for H/I be only $60-$90 and the reloads be $25 for a 3 pack is a very nice option.. Talk to your local club about getting a GSE to keep it's membership going because after this past week, we're going to have a very very slow 8+ months and nothing states that he's going to make a decision at that time anyways.. PS. Both Tripoli and NAR allow people to launch level 1 on the Rattworks H70.. 29mm x 18" long.. only downside is that you're basicly required to get some kind of electronics since hybrids don't have motor ejection.. >hybrid. Are any of you using hybrid? Why is it not more accepted by >the HPR community as a whole? How many pink pickup trucks do you see on the highway? Not many, because a Real man wouldn't be caught dead in a pink pickup. Rocketry is the same in a lot of ways. - hybrids don't "sound" like a real rocket motor - no colored smoke On a ROL forum, Gary from Aerotech once commented that high power rocketry isn't about ISP. It's good that he understands his market. Sometimes it seems like model rocketry is glorified fireworks. > >hybrid. Are any of you using hybrid? Why is it not more accepted by > >the HPR community as a whole? [quoted text clipped - 11 lines] > > Sometimes it seems like model rocketry is glorified fireworks. While I agree that the BATFE thing is crazy and I can't wait to be able to not have an LEUP, comparing Hybrids with a Pink Pickup Truck is pretty bad.. saying that they don't have colored smoke and the fact that the "sound" is different is pretty bad on your part.. They do have sparky motors and depending on the fuel material, you can get either Black or White smoke.. ooohh.. so I don't have Red, Blue or Purple.. what a loss? Tell the guys that built the "Hybrid" Space Ship One that they won the X-Prize in a pink pickup truck and see the reaction you'll get.. >While I agree that the BATFE thing is crazy and I can't wait to be able >to not have an LEUP, comparing Hybrids with a Pink Pickup Truck is [quoted text clipped - 5 lines] >Ship One that they won the X-Prize in a pink pickup truck and see the >reaction you'll get.. The guys who built SS1 cared about ISP and didn't care about a macho sound or colored smoke. They weren't flying HPR, they were flying a commercial rocket. There _is_ a difference. You can say it's "bad", but I call the shots as I see the attitudes on the launch field and on RMR. I don't care what the color of your rocket's smoke is, or what color you painted it, or if your paint has runs in it. I'm a miniority in that aspect. I see more people oogling about red flame or black smoke than about the impulse of a motor. Why does Aerotech offer a wide varieties of _color_ instead of thrust level / burn time, etc? I mean, what's great about a Readline motor other than the red colored flame? Why do people fly sparky motors, when all the sparking material does is rob the motor of performance? I've also discovered that to most fliers the paint job of the rocket is more important than how it flies. Go to a launch with a bucket full of unpainted rockets and see how many people give you crap about it. I used to, and even though I now do a paint job of some sort on all my rockets, I still have a reputation of flying unpainted rockets. >Why does Aerotech offer a wide varieties of _color_ >instead of thrust level / burn time, etc? If you look closely, you will find a relationship between color and ISP. It doesn't have to be that way but it generally is within a manufacturer's product line. Phil > You can say it's "bad", but I call the shots as I see the attitudes on the > launch field and on RMR. Glen, I think you've hit the nail on the head. I get way more comment about the one sparky hybrid I shoot in a weekend than the six other "conventional" hybrids I send aloft. Kevin OClassen >>hybrid. Are any of you using hybrid? Why is it not more accepted by >>the HPR community as a whole? [quoted text clipped - 11 lines] > >Sometimes it seems like model rocketry is glorified fireworks. 60% rocketry 40% pyrotechnics. As far as Gary - if he didn't make the stuff, people wouldn't use it - at least with his hardware. Phil Who's Gary? > >>hybrid. Are any of you using hybrid? Why is it not more accepted by > >>the HPR community as a whole? [quoted text clipped - 16 lines] > > Phil It was a reference form the message I was replying to. Gary Rosenfeld for Aerotech. Phil . >Who's Gary? >> [quoted text clipped - 18 lines] >> >> Phil > - hybrids don't "sound" like a real rocket motor You haven't heard a RATTworks K240 have you? It puts a smile on even the hardcore APCP fans. > Sometimes it seems like model rocketry is glorified fireworks. The First lady of the NAR figured that out at her first HPR launch...  SignatureBob Kaplow NAR # 18L >>> To reply, there's no internet on Mars (yet)! <<< Kaplow Klips & Baffle: http://nira-rocketry.org/Document/MayJun00.pdf www.encompasserve.org/~kaplow_r/ www.nira-rocketry.org www.nar.org S&T is becoming this decades Steve Weaver! >> Sometimes it seems like model rocketry is glorified fireworks. > > The First lady of the NAR figured that out at her first HPR launch... Who is the first lady of NAR ? I've been in the NAR since the early 70s and never heard of that one. >>> Sometimes it seems like model rocketry is glorified fireworks. >> The First lady of the NAR figured that out at her first HPR launch... > > Who is the first lady of NAR ? > > I've been in the NAR since the early 70s and never heard of that one. She's the wife of the NAR President. Or maybe Bob in a dress. SignatureSteve Humphrey (replace "spambait" with "merlinus" to respond directly to me) > >>> Sometimes it seems like model rocketry is glorified fireworks. > >> The First lady of the NAR figured that out at her first HPR launch... [quoted text clipped - 6 lines] > > Or maybe Bob in a dress. Thanks, Steve. I'll be all day getting THAT image out of my head. Bill Sullivan You're just jealous because the voices don't talk to YOU! > Who is the first lady of NAR ? > I've been in the NAR since the early 70s and never heard of that one. The president's wife. Just like any other president. SignatureBob Kaplow NAR # 18L >>> To reply, there's no internet on Mars (yet)! <<< Kaplow Klips & Baffle: http://nira-rocketry.org/Document/MayJun00.pdf www.encompasserve.org/~kaplow_r/ www.nira-rocketry.org www.nar.org S&T is becoming this decades Steve Weaver! Glen Clearly you're thinking of old hybrids. Yes they hissed and didn't have a smoke trail, but that stuff is ancient history. There is much better stuff available now. You should try the stuff from Contrail. They sound like (some reloads sound even better) than the equivalent solid at the same impulse rating. And depending on the vendor you can even get sparky and skidmark equivalents. Yeah, hybrids still might not quite the "oomph" of the solids, but you have a handful of new vendors making great strides. -Tim > >hybrid. Are any of you using hybrid? Why is it not more accepted by > >the HPR community as a whole? [quoted text clipped - 11 lines] > > Sometimes it seems like model rocketry is glorified fireworks. Hybrids are a lot of fun. But you can't do motor based ejection systems. So you have to use electronics. And that means (for most people) ematches and BP. Doug Pratt has nichrome based canisters that avoid the e-match issue. But you still need BP or Pyrodex and you are supposed to have a LEUP to use either in a hobby rocket. > Hi Everyone, > I got my L1 cert at the October skies, TCC launch last weekend, and I [quoted text clipped - 7 lines] > hybrid. Are any of you using hybrid? Why is it not more accepted by > the HPR community as a whole? SignatureWill Marchant, NAR 13356, Tripoli 10125 L3 kc6rol@amsat.org http://www.spaceflightsoftware.com/will/ >From what I understand, we are allowed to have BP without a permit. Second Amendment no? It doesn't bother me that you can't use motor ejection since I intended on dual deployment anyway. > Hybrids are a lot of fun. But you can't do motor based ejection > systems. So you have to use electronics. And that means (for most [quoted text clipped - 17 lines] > Will Marchant, NAR 13356, Tripoli 10125 L3 > kc6rol@amsat.org http://www.spaceflightsoftware.com/will/ http://tinyurl.com/ty6sx says you may have 50 pounds for use in antique firearms which is why http://www.tripoli.org/tmt/LEUP_filing.shtml says to list BP on your LEUP application. Do a search and you'll come up with numerous references such as http://www.space-rockets.com/homeland.html The discussions I've seen about Pyrodex say the situation is the same. The restrictions on selling it are much less than BP which is why it is seen in many more retail outlets than BP. But the claim, by people who have studied the situation much more than I have, is that if you intend to use it in something other than a firearm then you need a LEUP. Please don't argue with me about how little sense this makes. I agree completely. 8( > From what I understand, we are allowed to have BP without a permit. > Second Amendment no? SignatureWill Marchant, NAR 13356, Tripoli 10125 L3 kc6rol@amsat.org http://www.spaceflightsoftware.com/will/ > The discussions I've seen about Pyrodex say the situation is the same. > The restrictions on selling it are much less than BP which is why it is > seen in many more retail outlets than BP. But the claim, by people who > have studied the situation much more than I have, is that if you intend > to use it in something other than a firearm then you need a LEUP. Will, Thanks for pointing out the discussions about Pyrodex. I was not aware people were being mislead on the use of Pyrodex without an ATFE license. Actually, Pyrodex is not covered by Federal Explosives Law. Below is a statement from the Pyrodex MSDS sheet provided by Hodgdon, the manufacturer of Pyrodex. Regulatory Information: Pyrodex is Extremely Flammable. Pyrodex is not an explosive regulated by Federal Explosive Law, but may explode if misused. Pyrodex is not smokeless powder, but is approved to ship (DOT) and store (NFPA) as such. Pyrodex is not allowed on passenger aircraft, but may be loaded into ammunition which may be allowed. It may be shipped as a flammable solid by road, rail, vessel, or cargo only aircraft, or as an explosive by road, rail or vessel. While Pyrodex contains no nitrocellulose, the flammable solid proper shipping name is "Smokeless powder for small arms". DOT classifications follow: Flammable Solid (see 49 CFR 173.171): Smokeless powder for small arms, 4.1, NA3178, PG I Explosive: Propellant, solid, 1.3C, UN0499, PG II John Wickman > The discussions I've seen about Pyrodex say the situation is the same. > The restrictions on selling it are much less than BP which is why it is > seen in many more retail outlets than BP. But the claim, by people who > have studied the situation much more than I have, is that if you intend > to use it in something other than a firearm then you need a LEUP. Will, Thanks for pointing out the discussions about Pyrodex. I was not aware people were being mislead on the use of Pyrodex without an ATFE license. Actually, Pyrodex is not covered by Federal Explosives Law. Below is a statement from the Pyrodex MSDS sheet provided by Hodgdon, the manufacturer of Pyrodex. Regulatory Information: Pyrodex is Extremely Flammable. Pyrodex is not an explosive regulated by Federal Explosive Law, but may explode if misused. Pyrodex is not smokeless powder, but is approved to ship (DOT) and store (NFPA) as such. Pyrodex is not allowed on passenger aircraft, but may be loaded into ammunition which may be allowed. It may be shipped as a flammable solid by road, rail, vessel, or cargo only aircraft, or as an explosive by road, rail or vessel. While Pyrodex contains no nitrocellulose, the flammable solid proper shipping name is "Smokeless powder for small arms". DOT classifications follow: Flammable Solid (see 49 CFR 173.171): Smokeless powder for small arms, 4.1, NA3178, PG I Explosive: Propellant, solid, 1.3C, UN0499, PG II John Wickman Thanks, John! I'm happy to have been misinformed and to learn that Pyrodex is OK for use in rockets without a LUEP! Doug Pratt has some information at http://www.pratthobbies.com/info_pages/pyrodex/pyrotest.htm about using his Nichrome based canisters with Pyrodex. I think that means you can do a completely LEUP-less high power rocket if you fly a hybrid... Best wishes, Will >> The discussions I've seen about Pyrodex say the situation is the same. >> The restrictions on selling it are much less than BP which is why it is [quoted text clipped - 27 lines] > > John Wickman SignatureWill Marchant, NAR 13356, Tripoli 10125 L3 kc6rol@amsat.org http://www.spaceflightsoftware.com/will/ > Thanks, John! I'm happy to have been misinformed and to learn that > Pyrodex is OK for use in rockets without a LUEP! Doug Pratt has some [quoted text clipped - 3 lines] > Best wishes, > Will People have been using black powder for years to make their parachute activation device systems. I've seen no posts or discussions of raids, arrests, or even warnings. Maybe you should ask more questions before reposting 'discusion advice'? Will, Thanks for the link. Doug did a nice job with the video presentation. As he points out the key is using electrical tape to seal the end of the Pyrodex P canister. I've used 1/2 " PVC pipe and an end cap on one end. I cross the open end of the pipe with electrical tape making a cross on the open end. Then, I put layer around the perimeter of the open end to hold those two pieces more securely in place. For ignition I use a 1/2" to 3/4" long piece of 36 gauge NiCr wire. No coating on the wire, just plain. It is wrapped around the wire and inserted into the Pyrodex. I use a little wadding to hold the Pyrodex down in the base of the pipe by the end cap so the powder stays in contact with the NiCr wire. Works every time. For homemade, motors with a delay and charge, I use Pyrodex P as well. Just seal the open end of the ejection charge opening the same way with electrical tape. I don't know if it is necessary, but I also add an extra gram of Pyrodex P from what I would use if going with 4F black powder. I haven't used black powder in years and never had a problem in over a hundred flights. John > Thanks, John! I'm happy to have been misinformed and to learn that > Pyrodex is OK for use in rockets without a LUEP! Doug Pratt has some [quoted text clipped - 40 lines] > Will Marchant, NAR 13356, Tripoli 10125 L3 > kc6rol@amsat.org http://www.spaceflightsoftware.com/will/ Well then we should mount our rockets onto our guns and use the pyrodex to light them off. Oh.... That would be a missle launcher. Oh well. KT > Hybrids are a lot of fun. But you can't do motor based ejection systems. > So you have to use electronics. And that means (for most people) ematches > and BP. Doug Pratt has nichrome based canisters that avoid the e-match > issue. > But you still need BP or Pyrodex and you are supposed to have a LEUP to > use either in a hobby rocket. What makes you 'believe' that? you think there won't be any international air shipping restrictions on hybrids (the non pyrotechnic type that is)? I mean its like shipping plastics. Of course the GSE would be expensive.. SignatureTAI FU > Hi Everyone, > I got my L1 cert at the October skies, TCC launch last weekend, and I [quoted text clipped - 7 lines] > hybrid. Are any of you using hybrid? Why is it not more accepted by > the HPR community as a whole? Liz, To make this simple and sweet... YES YES HELL FING YES! Hybrids give you better performance than solids, and at a FRACTION of the cost, and NO GOVERNMENT regulation... think about that as your rule over your lizards! Lunar > Hi Everyone, > I got my L1 cert at the October skies, TCC launch last weekend, and I [quoted text clipped - 7 lines] > hybrid. Are any of you using hybrid? Why is it not more accepted by > the HPR community as a whole? > Why is it not more accepted by > the HPR community as a whole? IIRC I heard someone say they look like a pain in the rear. SignatureTweak >> Why is it not more accepted by >> the HPR community as a whole? >> > IIRC I heard someone say they look like a pain in the rear. Almost always voiced by someone who has not flown hybrids. IIRC, when reloadable motors first hit the market people said they were a pain in the rear. Oh, and unreliable too. I rarely see people make a big deal when an APCP motor spits an igniter or chuffs on the pad. But if a hybrid fails to launch on the first attempt there is a loud outcry about how unreliable and complicated they are. FWIW I do failure analysis on all my flights and the biggest problem I have with hybrids is getting a complete fill. That's mainly a procedural problem and I'm getting better every flight. Are hybrids more complex? Sure, who said rocket science was easy B-) > >> Why is it not more accepted by > >> the HPR community as a whole? [quoted text clipped - 12 lines] > getting better every flight. Are hybrids more complex? Sure, who said > rocket science was easy B-) Gotcha, ya sucka. Touchy touchy. SignatureTweak >From this discussion and the research I have done, I am sold on the hybrids. I think the future of AP is too unclear to invest a lot of money in hardware. I also like the fact that there seems to be no reasonable limit on the ultimate power you can get from these systems. I contacted my local club and hopefully I can get them to move on hybrids, but if they don't I'll probably still invest in my own ground support. It looks like you can get started with the less expensive ground support for a few hundred. It is a difficult decision which system to buy. For those that fly hybrids, which system should I go with? I'm looking in the I, J, and K class area since I would like to Cert L2 on a hybrid, buy still fly on L1. Can I use some of the same ground equipment on different systems with maybe small modifications such as fittings, adapters? So I guess I'm looking for cost and versatility in my decision. I'll leave the sparky-smokey things for later ;-) Any help will be appreciated since this is a pretty tough choice with my still limited knowledge. > >> Why is it not more accepted by > >> the HPR community as a whole? [quoted text clipped - 12 lines] > getting better every flight. Are hybrids more complex? Sure, who said > rocket science was easy B-) Liz, Hybrid support is available at your local club(s). I own GSE for Ratt type monotube hybrids. And AeroPAC owns GSE for Hypertek motors, which can be made available at both LUNAR and TCC launches. You see, you have an advantage... You know several of the officers in all 3 clubs... 8^) (We met at October Skies. My buddy Dave did your certification. BTW, Dave is the recording secretary for LUNAR, and I'm Launch Director for AeroPAC, and we're both good buddies with the equipment guys for both clubs. You want GSE for hybrids? You've got it...) 8^) James L. Marino SAS, LUNAR, TCC, AEROPAC, NAR #75764 L3 TRA #9489 L3 JPS Propulsion KI6BZS (@ @) ---o00-(_)-00o--- Will Work for AP > >From this discussion and the research I have done, I am sold on the > hybrids. I think the future of AP is too unclear to invest a lot of [quoted text clipped - 29 lines] > > getting better every flight. Are hybrids more complex? Sure, who said > > rocket science was easy B-) Thanks James, Great News James! It's great to hear from you. So what's your preference for L1 - L2 hybrids? Given that LUNAR has GSE, what would I need to check hybrids out besides the motor and reload? I guess if I end up going with hypertek, I'll need the ULS Module 3: GOX/HV Ignition Module? I already have an O2 tank. I can't find the RATT works website so that concerns me a little, but I kind of like the pyrogen ignition. How's RATT doing as a company? Will they still be supporting their motors? The hypertek motors are attractive, but they do need the high voltage ignition. As you can tell, I'm still in the fact gathering phase, but I've kind of hit a wall. Are there any reviews such as pros and cons of the different systems? Thanks for all help. Laura > Liz, > [quoted text clipped - 53 lines] > > > getting better every flight. Are hybrids more complex? Sure, who said > > > rocket science was easy B-) Laura, I've flown the Ratt I80 and the Ratt K240. Both nice motors. I also own(ed) and flew an AeroTech 54mm hybrid, but I sent the flight tank to Gary for repair about two weeks before the fire in Vegas. Bummer. Gary said he's going to get me a replacement, and that they're working on getting some reloads made, but there's a problem getting the little pyro pellet that they use for their pyro valve. All three of the motors I've flown use APCP grains that are < 62.5 grams, so no permits involved. A word of warning... Don't use any of the accelerometer based electronics in a hybrid powered rocket. Use a baro altimeter. There's a problem with accelerometers detecting launch with hybrids. Has to do with the oscillation of the thrust. I'll be using a PerfectFlite MAWD with mine. I don't have a clue what's up with Ratt Works. He does motors as a side thing to his machining business, so they may be busy with higher paying customers. But I'm pretty sure he's still in business down in Monterey. The thing to keep in mind for the Ratt motors is "build light." They aren't the thrustiest motors around, but they are very kool, fun to use, and cheap to fly. Pretty sure Bob has them in stock at www.aerocon.com. Tell him I sent you. Bob's good people. He will know better than I about continued support for the Ratt motors. Ask him. I have a bird in construction to use the I80 Ratt, and need to machine an adapter to fly the K240 in my Comp4 (the K240 is an odd size, 2.5" mmt required. Since the Comp4 has a 75mm mount, making an adapter will be a piece of cake.) That is coming. I have to concentrate on the M flight at Snow Ranch for the time being, but both hybrids will fly this season at the ranch. But I do need to get my Beeline GPS up and running before flying an M or any of the hybrids. I'm addicted to getting them back. If you decide to go with the Hypertek motors, no problem. The AeroPAC trailer is at Richard's shop in Oakland, and I know he'll be more than happy to bring the GSE out to a launch for use, O2 and high tension included. So really, all you need is a motor and a bird in which to fly it. Please let me know if I can be of any assistance in your travels through the world of rocketry. More than happy to help. Oh, and to answer your other question, the Ratt K240 would be a killer motor for an L2 cert. Build a bird, buy a reload, and I'll be happy to loan you the motor and the GSE. (Standard loaner agreement applies.) Build your bird with a 75mm mount and a Slimline retainer, and I'll throw in the adapter, too. That way, venting won't be a problem. My adapter will vent out the bottom. And be sure to make the booster section long enough (4 feet should do) for the motor. It's over 3 feet long. James > Thanks James, > Great News James! It's great to hear from you. [quoted text clipped - 11 lines] > Thanks for all help. > Laura > A word of warning... Don't use any of the accelerometer based > electronics in a hybrid powered rocket. Use a baro altimeter. There's a > problem with accelerometers detecting launch with hybrids. Has to do with > the oscillation of the thrust. I'll be using a PerfectFlite MAWD with > mine. James, I'd disagree with you on this one. I've used Gwiz LC & MC flight computers for every hybrid flight I've made (42 so far) and these are definitely accelerometer based units. They've worked perfectly every time. The specified launch detect is simply 2+G for 1/2 second. I like the Gwiz LC Basic (apogee only deployment) for smaller, low altitude birds, because no vent holes are required and you have a lot of freedom in mounting the device. I understand there historically have been some problems with certain types of flight computers being affected by high frequency signals generated by the Hypertek ignition system's spark gap. That was, frankly, before my time, and obviously not pertinent to all hybrids. Not a thing wrong with baro based computers-- the MAWD is an excellent device. Nothing wrong with accelerometer based units either. Kevin OClassen Kevin, Glad to hear you're having success with the GWiz. I'm sure Rob and Larry would be happy to hear that also. Perhaps I'm a bit over cautious, but I crashed a bird with a K240 Ratt using an accelerometer. It wasn't a GWiz, but it didn't live long. It was an AcceloRocket accelerometer. Worked fine on the J415, but failed to detect on the K240. Talk about depressed. That was a nice rocket, right up until impact. 8^( I'll be finding out how well the GWiz will work this winter. Going to mount the MAWD in the av bay of my Comp4 along side the (2) GWiz units that are already in there, and see what happens with the K240. (Plenty of room. I AM a big GWiz fan. Fly with Rob and Larry, the GWiz Partners. Currently beta testing the new LCX for them. Nice unit.) James > > A word of warning... Don't use any of the accelerometer based > > electronics in a hybrid powered rocket. Use a baro altimeter. There's a [quoted text clipped - 21 lines] > > Kevin OClassen James, Please allow me to correct myself - there *is* apparently a problem with some accelerometers and hybrid engines, having to do with sampling rates and motor 'frequency'. I asked about it over in the yahoo group hybridrockets and got an excellent explanation, complete with links to more information. I love this learning curve, and one of these days I'll learn to ask the questions first. Kevin O PS> Thanks for mentioning the LCX. I hadn't visited the GWiz site in a while, and had not heard of this computer. I have been considering a second dual-deploy flight computer, and had almost settled on a RocketMotion Mission Control. The LCX, while not quite as full featured is at a very attractive price, and GWiz have been very reliable for me, with great product support. Now I have to try to decide.... :) Any idea when this will hit the market? Kevin, Not sure when it will hit the market, as we're still in the testing phase. Really, it shouldn't be too far off. But I can say that I like it, and so far, it has worked quite well. I like being able to program the low altitude event, and the timer function allowed me to use it as a back-up unit in my ARLISS M rocket. James > James, > [quoted text clipped - 16 lines] > > Any idea when this will hit the market? James, Thanks again for the generous help. I found a hybrid motor group: http://groups.yahoo.com/group/hybridrocketmotors/ Someone asked the same question regarding the RATT website. http://groups.yahoo.com/group/hybridrocketmotors/message/5301 Apparently the RATT website is being updated and a preview of the new site can be seen here. http://www.rattworks.net/draft/ (I'm sure that link will only be valid for a short while.) I may take your advice on the K240 for L2 cert. I don't know if I'll pull it off for Snow Ranch, but in the mean time I'll look into the I class RATTs for the upcoming Snow Ranch launches. I'm not sure what the "standard loaner agreement" is, but I'm sure it's reasonable. Good luck on the M flight sounds exciting. Oh one more question. Are the grains for these hybrids unique or are they some what interchangeable? I'm only concerned with the availability of fuel in the future. >Please let me know if I can be of any assistance in your travels > through the world of rocketry. More than happy to help. Oh, and to answer [quoted text clipped - 23 lines] > > Thanks for all help. > > Laura Laura, The "standard loaner agreement" is "you break or lose it, you bought it." Other than that, give it back clean, and no charge. 8^) Yup, Ratt Works is still there. I don't think there will be a problem getting grains for any of their motors for the foreseeable future. You could always make grains for them, but that would invalidate the certification for the motor, and classify it as Ex. Hybrids will burn just about anything as a fuel grain. And of course there's no rush to get to L2. Plenty to learn and lots of fun to be had flying L1, that's for sure. Looking forward to seeing you at the ranch. Come on rain! Get that ranch green! James > James, > Thanks again for the generous help. [quoted text clipped - 42 lines] > > > Thanks for all help. > > > Laura Hey James, Thanks again. I signed into your webpage so that you have my email. Would it be ok to take some of the conversation out of RMR? I'll try not to wear out my welcome, but I do have some specific questions regarding LUNAR and hybrids and eventually the rest of the group will probably get bored. I'll start with first of many questions. (sorry-you kinda asked for it!) I was looking at the thrust on some of the hybrid motors and they seem kind of low. Do you have a recommendation on a L1 hybrid that can safely lift a 5.5-6lb rocket and will be easily supported at Snow Ranch? > Laura, > [quoted text clipped - 68 lines] > > > > Thanks for all help. > > > > Laura > Hey James, > Thanks again. I signed into your webpage so that you have my email. [quoted text clipped - 3 lines] > probably get bored. I'll start with first of many questions. > (sorry-you kinda asked for it!) <snip> Liz (may I call you, Liz?), I don't know that you could possibly wear out your welcome here by asking the questions you are asking. I, for one, am following your project with interest as I am also looking at hybrids. If you and the previous respondents don't mind, I would encourage you to continue on rmr. But, if you are uncomfortable with how it is going here, please let us know how things are going as you proceed. Best wishes and clear skies, SignatureGary *********************************************** * "summum jus, summa injuria est" * * http://home.comcast.net/~bollesg/index.html * * bollesg at comcast dot net * *********************************************** Gary, Thanks for the encouragement. This thread could get pretty long, but if others are interested I am all for it. >From my first steps into the world of hybrids it seems like a pretty young and dynamic area of rocketry. It's bringing me down the path of "rocket science" and I've stumbled onto some pretty interesting sites. Like this one: http://www.islandone.org/LEOBiblio/SPBI101.HTM There is a lot to learn and the challenges to using hybrid and the fact that it seems to be still evolving is exciting. I'm not rich and the family already thinks I'm nuts for spending so much time and money on rockets so I want to make a sound purchase. Luckily, I'm in the area of Livermore California so I will get some help with GSE from LUNAR. It seems like the GSE is compatible (with slight variations) with many of the different systems. James, I am also looking at the contrails. I've got my eye on the I-333 or the I-307. Does LUNAR have the GSE for these? It's still unclear to me what type of GSE is necessary for the contrails. For L2 I will probably go with the K240. It looks like contrails and RATT use the same connectors. No? Anyway- thanks I'll try and look into the CSFM California Certification. Thanks again all. Laura A.K.A lizardqueen > > Hey James, > > Thanks again. I signed into your webpage so that you have my email. [quoted text clipped - 29 lines] > * bollesg at comcast dot net * > *********************************************** > I am also looking at the contrails. I've got my eye on the I-333 or > the I-307. Does LUNAR have the GSE for these? It's still unclear to > me what type of GSE is necessary for the contrails. Laura, The GSE for Contrail motors is the same as RATT or any other monotube hybrid. The only odd requirement is for a 24V ignition source, since the Contrail motors use a carbon film resistor to initiate their motors, rather than an igniter or ematch. Most folks swap the resistor out and use an ematch in its place. Kevin O Thanks Kevin, I'm glad to hear that some folks use ematches. I'm not sure why I'm resistant to the high voltage ignition (no pun intended) except maybe it's one more thing to buy and one more new thing to digest. Maybe I'll warm to the idea eventually. > > I am also looking at the contrails. I've got my eye on the I-333 or > > the I-307. Does LUNAR have the GSE for these? It's still unclear to [quoted text clipped - 9 lines] > > Kevin O Laura, All of the monotube motors will use the same GSE as the Ratt. Just have to be sure we have the right connector to fit the fill tube. And I have access to many types and sizes of brass fittings for this. So, if the Contrails are CSFM certified, we're there. 8^) James > Gary, Thanks for the encouragement. > This thread could get pretty long, but if others are interested I am [quoted text clipped - 54 lines] > > * bollesg at comcast dot net * > > *********************************************** > I am also looking at the contrails. I've got my eye on the I-333 or > the I-307. Laura, The Contrail motor hardware "combinations" can be confusing. Just FYI, the I307 and the I333 use the same hardware, just a different reload kit. In fact, that hardware can be used to make 4 motor combos: I-307 573NS I-333 556NS I-400 432NS I-290 Sparky 488NS The I307 is a great motor. A poor-quality video of that motor in a 10lb rocket can be found at http://back2bed.com/rockets/JustForLaughs.wmv Kevin O Kevin, This Contrail System is looking better and better. -> I-307 573NS -> I-333 556NS -> I-400 432NS -> I-290 Sparky 488NS I did notice all these motors use the 36 inch motor hardware. Do the necessary nozzles/injectors come with the different grains? Are the nozzles reusable or do I replace the nozzle after every flight like an AP reload? Some one over in http://groups.yahoo.com/group/hybridrocketmotors/ made a good point. Using the high voltage ignition saves money on pyro-ignitors and may placate the CSFM. I still have no idea on how to find out if a motor is CSFM certified. I do feel the progress here-I am starting to feel the plastic burning a hole in my wallet. > > I am also looking at the contrails. I've got my eye on the I-333 or > > the I-307. [quoted text clipped - 14 lines] > > Kevin O Contrail Motors come with the necessary igniter, injector and line set when purchased. Each of those items, including the fuel grain are single use items. The Nozzle is a reusable graphite nozzle that is included with your purchase of hardware. Contrail Motors do not require CSFM Approval. Hybrids are not classified by the CSFM and do not need the same approval as do AP Motors. The Hardware Kevin refered to actually has 8 different Reloads certified in it. I-210-PVC I-333-PVC J-150-HP J-246-HP I-307-HP I-400-HP I-727-HP I-290-Sparky Please note the I-727-HP uses a special Injector and Nozzle which are not included with the regular hardware. Tom Sanders Contrail Rockets > Kevin, > This Contrail System is looking better and better. [quoted text clipped - 32 lines] > > > > Kevin O Thank you for verifying that the hybrids don't require CSFM approval. That's the info I'm getting from our member's list. 8^) James > Contrail Motors come with the necessary igniter, injector and line set > when purchased. Each of those items, including the fuel grain are [quoted text clipped - 57 lines] > > > > > > Kevin O Thanks Tom, James, and Kevin, Ok I am out of excuses and it looks like I will go with the 38mm, 36 inch contrail hardware. We have GSE and I even have a rocket that I can modify to use the motor. It occurs to me that you could use this same hardware for an L2 certification. Maybe I can have this ready for Snow Ranch with a little luck. By the way, can you use credit cards and dollar bills as fuel grain? Thanks again, Laura > Contrail Motors come with the necessary igniter, injector and line set > when purchased. Each of those items, including the fuel grain are [quoted text clipped - 57 lines] > > > > > > Kevin O > Maybe I can have this ready for Snow Ranch with a little luck. > By the way, can you use credit cards and dollar bills as fuel grain? > Thanks again, Laura Laura, Dollar bills and credit cards burn to quickly. Some times they ignite spontaniously. Mine are always burning a hole in my pockets. KT > Dollar bills and credit cards burn to quickly. Some times they ignite > spontaniously. Mine are always burning a hole in my pockets. Look out. If they burn faster than 7mm/sec, you're gonna need an LEUP for a credit card. SignatureBob Kaplow NAR # 18L >>> To reply, there's no internet on Mars (yet)! <<< Kaplow Klips & Baffle: http://nira-rocketry.org/Document/MayJun00.pdf www.encompasserve.org/~kaplow_r/ www.nira-rocketry.org www.nar.org S&T is becoming this decades Steve Weaver! Laura, Looks like Tom has it. The hybrids don't require CSFM approval. 8^) James > Kevin, > This Contrail System is looking better and better. [quoted text clipped - 32 lines] > > > > Kevin O No problem, Laura. Reach me directly at jmarino1 (at) sbcglobal (dot) net. Contrail looks like it has some pretty good numbers for it's motors. But... Are they CSFM certified for use in Kalifornia? I don't know... But I'll see what I can find out. James > Hey James, > Thanks again. I signed into your webpage so that you have my email. [quoted text clipped - 80 lines] > > > > > Thanks for all help. > > > > > Laura Try the Sky Ripper Motors (www.skyrippersystems.com). They really rock and are simple to use with most ground suport systems. Mark A Palmer > Hey James, > Thanks again. I signed into your webpage so that you have my email. [quoted text clipped - 93 lines] >> > > > Thanks for all help. >> > > > Laura Mark, I took a look at Sky Ripper Motors, but it's still not clear to me how the grains work. Do you have to weigh the N2O to change the impulse? One of the things that attracted me to Contrails is that I could see all the impulse possibilities with a set of hardware. I want to give Sky Rippers a chance so can you tell me a little about how the various impulse configurations work (or a link) or maybe why they rock. > Try the Sky Ripper Motors (www.skyrippersystems.com). They really rock and > are simple to use with most ground suport systems. [quoted text clipped - 100 lines] > >> > > > Thanks for all help. > >> > > > Laura > Mark, > I took a look at Sky Ripper Motors, but it's still not clear to me how [quoted text clipped - 10 lines] > > > > Mark A Palmer Laura, Despite recommending the Contrail motors, I think *very* highly of the Skyripper motors as well. Although they offer fewer grain / injector / nozzle combinations, they are strong performers, very reliable, and easy to fly. I find they are also easier to clean than the Contrail motors, generally showing far less blow-by. The quality of machining and finish is outstanding. Skyripper motors currently hold the hybrid H & I TRA altitude records. They are well worth a look. I certified L1 on the 38mm H155, and between the 29mm & 38mm motor sets I fly just as many SR motors as Contrail. FWIW, the 29mm Skyrippers are probably my favorite hybrid motors. They are serious performers, and very economical to fly. I recently lost one, and bought two to replace it, if that tells you anything. The 38mm SR motors have 2 certified motors per case size. You select the impulse by choosing the reload type: PVC is good, polypropolene (PP) is slightly better. The four SR 38mm cases give you eight motor combos, full G thru baby J. As far as weighing N2O - historically Aerotech hybrid motors required you to weigh and pre-load the N2O, but all of the current crop of monotube motors require you to fill the N2O flight tank from a distance of no less than 100 feet, just before launch. At a nominal operating pressure of 750psi, there is only something like a 2:1 safety margin on the flight tank.... not something you want to stand close to. Kevin O Kevin, I didn't get the impression that anyone was putting Sky Rippers down. I have read a lot of good things about them. Thank you for helping clarify some confusion about the grains. Am I wrong or do the contrail motors seem to have greater lift. My rockets are a little heavy. My L1 rocket weighed in at 5.5 pounds with glass and all. When I start to add electronics, I can see the weight going up even more. I will try to keep the weight down, but so far it's not my forte. Anyway, I guess I'm saying that I like the thrust that seems to be greater with the I impulse Contrails motors. From what I could find out about the Contrails motors and I could be wrong, it seems that the hybrid average thrust approaches the AP of the same class. I thought I saw that Sky Rippers, like the Contrails motors have a set of hardware that will work for both L1 and L2 flights. Let me know your thoughts.. I will be looking for some 29mm motors and I will certainly take your advice regarding the 29mm Sky Rippers. I like to fly some smaller rockets with my relatives in Illinois and the 29mm motors are just the ticket. As an aside, the fact that I go to Illinois to fly is another reason the hybrids look attractive since I can freely move them around without the cumbersome permits. Laura > > Mark, > > I took a look at Sky Ripper Motors, but it's still not clear to me how [quoted text clipped - 41 lines] > > Kevin O > Am I wrong or do the contrail > motors seem to have greater lift. My rockets are a little heavy. [quoted text clipped - 8 lines] > that will work for both L1 and L2 flights. > Let me know your thoughts.. Laura, Thrust numbers of hybrid rockets are hard to compare to that of APCP motors, for a couple of reasons. Take a look at http://www.skyrippersystems.com/documents/FAQ.htm About halfway down the page there is an outstanding explanation of how the operation of hybrids affects the certified thrust. Add to that monotube hybrids have a highly regressive thrust curve, and the initial thrust is much higher than the average thrust. I frequently launch a 6+ pound (dry weight) rocket on the SR H155, and it flies beautifully. The rocket, all up on the pad with nitrous loaded is a bit over 7 lbs. The Contrail motors do have good average thrust, but it comes at a price. A given amount of nitrous plus a given amount of fuel, burned at the same rate, yields a certain total impulse, no matter the manufacturer. The rub is in how fast it is burned. If you look at the impulse ratings for the "slow" Contrail motors you'll find they match the SR average and total impulse ratings pretty closely. What Contrail has done is to add different size nozzles and injectors, causing the engines to burn the same amount of oxidizer/fuel in a shorter time, giving higher AVERAGE thrust. However, as the motor speed goes up it appears that the efficency of the motor goes down, so that the faster motors have higher average impulse but lower TOTAL impulse. Not a huge amount, but enough to be noticeable. Also, the conditions under which the motors are rated/certified makes a difference. The most important factor is temperature of the N2O. If I understood correctly, SR bases its' ratings on an ambient temp of 70F (~750psi), Contrail on 85F (~875 psi). This difference will affect the published performance of the motor. As the temp of N2O rises it becomes less dense, thus offering less O2 for total thrust, though it pushes the average thrust up a bit. Personally, I like to use pressures of 650-700 psi, since it gives killer performance and creates much less strain on the hardware. I've seen folks tank and launch at 900psi, but I'll pass at that pressure... The Skyripper 38mm motor set does indeed span the range of motors from G to baby J, so is great for L1 & L2. Todd also has a series of 54mm motors in process for certification. One thing I noticed on the SR website is a larger nozzle/injector set for the 38mm motors, which will increase the average thrust of the motors to ~250NS on PP fuel. I'm looking into that for myself... Also, RockSim or SpaceCad are your friend :) When in doubt, sim it out.... Kevin O Thanks for replying Kevin. I could not have said it better myself. I recently flew the 29mm H at XPRS in my daughters Snitch. Easy set up easy clean up! In fact I found it mucheasier to build and clean then AT RMS. They are extremely reliable, simple and easy to use (1 set of internal components...Noxxle, Injector, bulk head etc). Nothing to mix up. I have seen a whole bunch of these motors fly..they sound, look and perform great! Mark Palmer >> Mark, >> I took a look at Sky Ripper Motors, but it's still not clear to me how [quoted text clipped - 47 lines] > > Kevin O > Yup, Ratt Works is still there. I don't think there will be a > problem getting grains for any of their motors for the foreseeable future. > You could always make grains for them, but that would invalidate the > certification for the motor, and classify it as Ex. Hybrids will burn just > about anything as a fuel grain. > > > > I can't find the RATT works website so that concerns me a little, but > I [quoted text clipped - 6 lines] > > > > Thanks for all help. > > > > Laura http://www.rattworks.net/draft/ It's still back under construction, but their links work to the different motors and pricing if you click on "Products" at the top.. Their domain expired earlier this year and someone snatched the name out from under them before they could renew so they lost their primary website.. The above site is what they're working on to rebuild it.. They're not going anywhere.. I just picked up the H70/I80 casings as well as the L600/M900 set and they've still got reloads for all of them.. Dave is a good guy, but this is not their primary business.. They're a very old machine shop (Monterey Machine Products) doing aerospace parts since the 50's so don't expect them to be picking up and going anywhere anytime soon.. > For those that fly hybrids, which system should I go > with? I'm looking in the I, J, and K class area since I would like to > Cert L2 on a hybrid, buy still fly on L1. Can I use some of the same > ground equipment on different systems with maybe small modifications > such as fittings, adapters? Skyripper, Ratt, or Contrail. These will all fly from Doug's ULS system + RTLS2 without any additional ground support, except various sized fittings. I personally like the Skyripper motors for reliability and Contrail for the large number of certified combinations. The monotube motors I fly use four different sizes of fill line, so I made a series of quick-connect hoses with the correct fitting on each end. That way swapping out the fitting is a matter of a few seconds and requires no tools. Kevin OClassen Thanks Kevin, I'm still trying to take it all in. A lot of information. > > For those that fly hybrids, which system should I go > > with? I'm looking in the I, J, and K class area since I would like to [quoted text clipped - 12 lines] > > Kevin OClassen > I'm still trying to take it all in. A lot of information. To give you even more food for thought, check out the yahoo group hybridrocketmotors A lot of those folks are doing stuff that is way over my head, but they are wellspring of advice and encouragement, and the archives are invaluable. Kevin O PS> If I were in your position (already L1), knowing what I know now, I'd probably start with the Contrail 38mm motor set. Motors from G100 to a 45% J800, reasonable hardware and reload cost, good performance. I used the 38mm set to certify L2. Alex, I found a PDF document with an article you wrote about hybrids. Do you have any ideas on which system is best to start with? I am mostly concerned with cost and versatility over the Classes H through K. I also need to know how to modify my rocket to accommodate the motors. I am currently am building a 3 inch rocket that would be nice to put the necessary motor mount into. I also have a 54mm, 4 inch rocket, but the motor tube is only about 16 inches long. I don't care so much about the sound or smoke, or even complexity. I look forward to a challenge. > >> Why is it not more accepted by > >> the HPR community as a whole? [quoted text clipped - 12 lines] > getting better every flight. Are hybrids more complex? Sure, who said > rocket science was easy B-) I have a 3" rocket with a 54mm mount that flies very nicely on a Hypertek 54mm 440cc or 835cc motors. With these two tanks I can put together 11 different motors ranging from an I260 to a K240, but mainly in the J range. With the smaller 300cc tank I can fly 6 different I combinations. I really like the Hypertek system and it was what I used to get into Hybrids. I've also flown RATTworks 29mm and 76mm motors. I personally don't like the 29mm RATTworks but love the 76mm K240. I have a WestCoast Hybrids I110 which I love, nice sound and smoke. The HT system uses non-pyro ignition which requires an O2 tank. Most of the mono-tube hybrids use a sliver of APCP (under 62.5g) to heat the motor and burn through the fill stem. If you like that concept and you want to fly L1 motors you should look at Skyripper or West Coast hybrids as good starter motors. If there are gas passers nearby, find out what they fly. As far as how to modify a rocket for hybrids, it's pretty simple. The rocket has to be long enough for the motor. You don't have to fully support the top part of the motor but you can't have the motor sticking out the top! Watch your stability to make sure you don't run into problems with extra weight at the back of the motor (sim it fully loaded with N2O). Make sure you have a way to vent the motor externally, which will vary depending on your motor. > Alex, > I found a PDF document with an article you wrote about hybrids. Do you [quoted text clipped - 5 lines] > motor tube is only about 16 inches long. I don't care so much about > the sound or smoke, or even complexity. I look forward to a challenge. Thank Alex, I appreciate all the information on the Hypertek motors. I didn't realize there were that many possible variations with the two tanks. Is it possible to ignite the Hypertek using pyrogen and do all the high voltage ignitors need O2? > I have a 3" rocket with a 54mm mount that flies very nicely on a > Hypertek 54mm 440cc or 835cc motors. With these two tanks I can put [quoted text clipped - 29 lines] > > motor tube is only about 16 inches long. I don't care so much about > > the sound or smoke, or even complexity. I look forward to a challenge. > > Why is it not more accepted by > > the HPR community as a whole? > > > IIRC I heard someone say they look like a pain in the rear. > -- > Tweak You must have a slightly higher level of intelligence and come from a better gene pool than typical solid motor rocketeers to fly hybrids...... ;-) > > > Why is it not more accepted by > > > the HPR community as a whole? [quoted text clipped - 8 lines] > > ;-) Ahhh, there IS someone else here with a sense of humor, or at least one who has been around for a while. ;-) Touche' SignatureTweak |
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