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  #11  
Old 01-03-2023, 12:26 PM
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georgegassaway georgegassaway is offline
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Note that all the engines on that site are higher than regular.

Estes A3-4T's are 15.95 Euros , equal to $16.82. Estes website price, $11.29. So, 49% higher price.

Estes D12's, 19.50 Euros, $20.58. Estes website price $13.49, for TWO.

Those D20 engines, cost 24.00 Euros, for THREE. So, actually CHEAPER than Estes D12's

Of course, they have the costs of shipping engines from the US and import fees and such.

So pretty much, if you want to do this hobby in Europe, it's gonna cost you a whole lot more.

Same for a lot of other countries overseas, other than those who have their own in-country engine makers who are *legally* making motors (which a lot of famous engines, like the Czech "Delta" engines, were made "underground", unregulated, illegal, but "under the radar", until an explosion killing someone).

IIRC, the cost of Estes & Aerotech engines in Australia is twice as much, if not more, due to shipping and import issues.
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Last edited by georgegassaway : 01-03-2023 at 08:36 PM.
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  #12  
Old 01-03-2023, 01:00 PM
BigRIJoe BigRIJoe is offline
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Quote:
Originally Posted by astronwolf
I'm sure it wasn't a dig on "the mighty D." They use a propellant with a higher specific impulse - probably a composite propellant.

Well, if they are, they're figured out a way to stage them. Or so they claim
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  #13  
Old 01-03-2023, 03:45 PM
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Quote:
Originally Posted by BigRIJoe
Well, if they are, they're figured out a way to stage them. Or so they claim


They might have a thermalight fuse sticking up from the top of the propellant. I staged Aerotech E6 motors using some old thermalight fuse material I got way back when FSI sold it. I read somewhere that was doable back in the late 80's and tried it with a modified Estes Apache 2. It worked, but even with a streamer I lost the upper stage to upper level winds carrying it away.
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  #14  
Old 01-03-2023, 04:06 PM
shockwaveriderz shockwaveriderz is offline
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Quote:
Originally Posted by astronwolf
I'm sure it wasn't a dig on "the mighty D." They use a propellant with a higher specific impulse - probably a composite propellant.

Yeah probably APCP and Polyisobutylene (butyl rubber)as a guess.
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  #15  
Old 01-03-2023, 04:20 PM
shockwaveriderz shockwaveriderz is offline
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Quote:
Originally Posted by Gus
TSP motors are made by Piotr Tendera in Poland.

Piotr is a very bright, really nice guy who makes competiton motors we have flown at times in Poland and Romania.

He cannot legally ship motors to the U.S. and the expense to get them certified to ship here is cost prohibitive ($30K - $50K per motor).

Steve


He also makes those super low power long duration jetex type motors for model aircraft.
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  #16  
Old 01-07-2023, 01:08 PM
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Quote:
Originally Posted by olDave
I looked at the data for the D20. How can they claim 67% more power than an Estes D?


D12 vs. D20 . . . "20" is 67% higher than "12" . . . Not Total Impulse, but Average Thrust.

Dave F.
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  #17  
Old 01-22-2023, 12:49 PM
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Quote:
Originally Posted by Gus
TSP motors are made by Piotr Tendera in Poland.

Piotr is a very bright, really nice guy who makes competiton motors we have flown at times in Poland and Romania.

He cannot legally ship motors to the U.S. and the expense to get them certified to ship here is cost prohibitive ($30K - $50K per motor).

Steve
There is a way around it (and Stuart Lodge, who almost single-handedly got model rocketry legalized in the UK despite the 1875 Explosives Act, has used it; it actually made at least one competition event possible at all): Diplomatic pouch! A few years ago, an ambassadorial or consular diplomat from an Eastern European country, who is a friend of his and also an avid space modeler, "imported" enough high-performance contest motors--types not yet certified and approved for import--via diplomatic pouch, to enable all of the contestants in a rocketry competition tournament to practice and compete with them. This has been done in other rather related situations, too; for example:

In his 1956 (and 1957, depending on the publisher) book "The Viking Rocket Story," Milton Rosen, the U.S. Navy's sounding rocket program chief, included an account about Dr. Herman Yagoda, perhaps the most knowledgeable Cosmic ray and space radiation research scientist of that era; he flew specially-prepared Cosmic ray-detecting film emulsions into space aboard at least one Viking sounding rocket, and:

Before the huge polyethylene plastic film Skyhook balloons and sounding rockets (the V-2, WAC Corporal B, Aerobee, and Viking) became available for lofting such payloads in 1946 - 1947, he took Cosmic ray emulsions up onto mountaintops, to get them above most of the atmosphere. He once tried to do this in the Himalayas in India, but because the film emulsions contained gelatin--made from cows, who are sacred and officially protected in India (Jeffyjeep has posted about that here on YORF, after doing contractor work in India)--Dr. Yagoda was prohibited from bringing his emulsions into the country. But:

Not long afterward, he neatly avoided the whole problem by arranging with a diplomat friend of his to bring the film emulsions into India in a diplomatic pouch. (One day, he also reassured Rosen--whose Viking round that was to carry Dr. Yagoda's Cosmic ray emulsions into space was experiencing one glitch after another--that "You will have no more problems with the rocket, now." When Rosen asked why, Yagoda smiled and said, "My gel has arrived." :-) )
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  #18  
Old 01-22-2023, 01:12 PM
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That may have worked momentarily in a country the size of Great Britain but it is of little use here. Those motors cannot be legally shipped in the United States without certification. And the cost to certify those motors are in the five to $10,000 range each. If there was some easy way to do this, the US team would’ve done it years ago to practice. But there isn’t.
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  #19  
Old 01-22-2023, 01:16 PM
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Quote:
Originally Posted by shockwaveriderz
He also makes those super low power long duration jetex type motors for model aircraft.
Thank you for that tip--I've been looking for new ones for years! Are *these* (see: https://www.sierrafoxhobbies.com/en...=TSP+jet+motors ) the TSP model jet motors (Jetex-like, but single-use, and built like BP mini or micro rocket motors, similar to Dr. Z's [Dr. Jan Zigmund's, see: http://minimakety.cz/rapier/other/I...07/index-en.php ] Rapier motors) to which you are referring?

I still have ten or so Rapier motors, but I have bought rocket motors (and rocket kits) from Sierrafox Hobbies before, with no problems, so I have no qualms about ordering the TSP jet motors from them. (Stefano Figini is also very helpful with arranging for the lowest-cost shipping options.) (I bought my Rapier jet motors from a UK hobby shop, which no longer carries them; I think Dr. Z no longer makes Rapiers.)
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  #20  
Old 01-22-2023, 01:35 PM
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Quote:
Originally Posted by Gus
That may have worked momentarily in a country the size of Great Britain but it is of little use here. Those motors cannot be legally shipped in the United States without certification. And the cost to certify those motors are in the five to $10,000 range each. If there was some easy way to do this, the US team would’ve done it years ago to practice. But there isn’t.
I understand that; it is a first step toward a permanent, universal solution (for the motor types in question), not a complete solution in and of itself. Also:

Another option, which might be an actual solution, could be to import them as firework devices, whose import requirements are much lower. I know that they couldn't be used in NAR, CAR, JAR, or other model rocket organizations' sanctioned contests and sport launches, but how many model rocket builders & flyers are even aware of these organizations, let alone members of them? I haven't been a NAR member for ten or fifteen years or so, and my father--who was a very active model rocketeer--knew about the NAR, but never had the slightest interest in joining it, because he saw no reason to do so (ditto for the AMA--Academy of Model Aeronautics--and he built and flew a lot of "from-kits" and "self-designed" model airplanes and gliders).
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http://www.lulu.com/content/paperba...an-form/8075185
http://www.lulu.com/product/cd/what...of-2%29/6122050
http://www.lulu.com/product/cd/what...of-2%29/6126511
All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com.
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