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bikegod
09-25-2006, 08:58 PM
Where exactly is the dividing line between low, mid and high power rocketry?

What started out as a little hobby of mine is starting to grow. I did notice that I have been liking larger (SLS) rockets and even built the LPSLV (over 40" tall).

Is Mid power a designation of size or engine thrust? Will a 20" rocket with an F engine be classified as a Mid power?

A Fish Named Wallyum
09-25-2006, 10:42 PM
I always thought of anything over a D as mid-power and anything over a G as high-power. YMMV. ;)

ghrocketman
09-26-2006, 08:28 AM
There is no real "official" definition between LPR and MPR; the unofficial definition of the dividing line between the two is anything over D power but not over 2 G's in a cluster is MPR.

HPR is somewhat defined as the following, any of which causes a rocket to be HPR:
Any single engine over 160 n/sec total impulse. (Such as a H128W)
Any single engine over 80 newtons average thrust. (Such as a G104T)
Any engine containing over 62.5gr. of total propellant (Such as a G33J)
Any combination/cluster of LPR/MPR engines that causes the total installed impulse to be over 320 n/sec (such as 10 Aerotech F52's).
Any rocket that weighs over 53oz. total at liftoff. (Such as a 10" diameter Nike-Smoke, even if you idiotically plan to try to launch it with a single D12-3)

Please note that the above HPR list is NOT all inclusive and may be incomplete.

Tweener
09-26-2006, 08:48 AM
I usually think of high power as anything I'd need a cert and\or FAA waiver to launch. :rolleyes: (Which I can't and don't. :( )

dwmzmm
09-26-2006, 09:18 AM
I've been told (in writing) that I can't test fly my FSI F100-8 for the OOP engine test fly the
NAR is allowing because it's been classified as a HPR motor...

Doug Sams
09-26-2006, 09:29 AM
There is no real "official" definition between LPR and MPR; the unofficial definition of the dividing line between the two is anything over D power but not over 2 G's in a cluster is MPR.

HPR is somewhat defined as the following, any of which causes a rocket to be HPR:
1. Any single engine over 160 n/sec total impulse. (Such as a H128W)
2. Any single engine over 80 newtons average thrust. (Such as a G104T)
3. Any engine containing over 62.5gr. of total propellant (Such as a G33J)
4. Any combination/cluster of LPR/MPR engines that causes the total installed impulse to be over 320 n/sec (such as 10 Aerotech F52's).
5. Any rocket that weighs over 53oz. total at liftoff. (Such as a 10" diameter Nike-Smoke, even if you idiotically plan to try to launch it with a single D12-3)6. Any combination of motors with combined proepellant mass in excess of 125g.


Please note that the above HPR list is NOT all inclusive and may be incomplete.
It's complete now :)

http://home.flash.net/~samily/stuff/HPR_metric8.pdf

Doug

Doug Sams
09-26-2006, 09:36 AM
Where exactly is the dividing line between low, mid and high power rocketry? The rmr faq has a pretty good discussion of mid-power including the FAA definition of Large Model Rocket. http://www.ninfinger.org/~sven/rockets/rmrfaq.1.html#q1

Is Mid power a designation of size or engine thrust? Will a 20" rocket with an F engine be classified as a Mid power?Your 20", F-powered rocket is definitely mid-power. I'm with everyone else - other than the FAA's LMR definition, the LPR-MPR line is quite fuzzy. I consider the range to be D-G, but E-G makes sense, too. That's for single engines, but a cluster of 6 C motors might be considered mid-power, too.

Doug

bikegod
10-09-2006, 08:14 AM
For those of you who have followed my various threads before, I have been building a larger rocket based on the SLS Laser. I treated myself to the optional motor mounts in order to get thrust needed to launch this mini behomoth, and finally decided to make the investment in a Reloadable Motor System.

My timing wasn't the best. After talking, and llistening to a lot of you, the choice became obvious that a 24mm would give me the most versatility (usuable in other kits that I currently own). But apparently there was an availability problem with the casings. It seemed like everywhere that I looked it was out of stock. I placed an order, waited six whole weeks and when it arrived, they inadvertantly shipped an 18mm motor.

Of course they made good on it, and shipped the correct part, and even told me to keep the 18 for my trouble.

Now, what am I going to do with the 18mm? It looks like Aerotech has 3 different loads for this casing, and all of my current kits that use A B or C engines would find themselves higher than my comfort level (and out of range of my eyesite). I could get some adapters and convert some of my D stuff, but that is what the 24 was for.

Was there more 18mm loads at one time? What do you personally use the 18mm RMS for?

ghrocketman
10-09-2006, 09:08 AM
At one time the 18mm Aerotech RMS 18 case also offered B, C, and even a "baby" 23 n-sec E engine reloads. The B, then the C were the first to be dropped apparently due to low sales, and I think the "E" was the last one dropped. I have not seen a reason for dropping the "E" engine, and in fact the only information I saw about this reload was that it was not ever certified....that may or may not be true, I don't know.
One rocket that the Aerotech 18mm D reloads are great for is the Estes/Semroc Mars Lander; it actually gets to a respectable height on this engine. I have also used one in my Estes Space Shuttle #1284 (the old one with the SRB's and ET). For me, this is the ONLY decent engine choice for the Space Shuttle since the demise of the Estes C5-3. The C6-3 NEVER produces a decent flight in this rocket.
I STILL find it totally IDIOTIC that Estes chose to keep the C6-3 and drop the C5-3, which is superior to the C6-3 in ALL parameters. I'd gladly choose to pay a 25% higher price (due to the higher cost of manufacturing a port-burning C) for C5-3's instead of the virtually worthless (unless in a cluster) C6-3.

In short, the RMS18 is great for all heavy/fat/draggy 18mm rockets.
Other good candidates include the Big Bertha, Fat Boy, and MANY of the old Estes "futuristic" rocket designs that were very draggy due to pods/fins/pseudo-engines all over the place.

dwmzmm
10-09-2006, 09:27 AM
At one time the 18mm Aerotech RMS 18 case also offered B, C, and even a "baby" 23 n-sec E engine reloads. The B, then the C were the first to be dropped apparently due to low sales, and I think the "E" was the last one dropped. I have not seen a reason for dropping the "E" engine, and in fact the only information I saw about this reload was that it was not ever certified....that may or may not be true, I don't know.
One rocket that the Aerotech 18mm D reloads are great for is the Estes/Semroc Mars Lander; it actually gets to a respectable height on this engine. I have also used one in my Estes Space Shuttle #1284 (the old one with the SRB's and ET). For me, this is the ONLY decent engine choice for the Space Shuttle since the demise of the Estes C5-3. The C6-3 NEVER produces a decent flight in this rocket.
I STILL find it totally IDIOTIC that Estes chose to keep the C6-3 and drop the C5-3, which is superior to the C6-3 in ALL parameters. I'd gladly choose to pay a 25% higher price (due to the higher cost of manufacturing a port-burning C) for C5-3's instead of the virtually worthless (unless in a cluster) C6-3.

In short, the RMS18 is great for all heavy/fat/draggy 18mm rockets.
Other good candidates include the Big Bertha, Fat Boy, and MANY of the old Estes "futuristic" rocket designs that were very draggy due to pods/fins/pseudo-engines all over the place.

In regards to the Estes Space Shuttle, after I reduced the add on fin size by removing one
inch (on all four fins), the C6-3 gave mine a very respectable altitude, with the model going
virtually straight up even in a slight 7 mph breeze. But I would agree that Estes should have
kept the C5-3's, as those were far more superior motors for the models they were intended
to be used for. They were really great when I flew my old Estes Saturn - V in the three
engine cluster configuration (and the Centuri Saturn 1-B).

Doug Sams
10-09-2006, 06:37 PM
But I would agree that Estes should have kept the C5-3's, as those were far more superior motors for the models they were intended to be used for. They were really great when I flew my old Estes Saturn - V in the three engine cluster configuration (and the Centuri Saturn 1-B).The C11-3 does a good job of replicating the C5-3's heavy lift capability, but Estes didn't do a good job of integrating it into the rocket portfolio. Several birds would have benefited from 24mm upgrades to accomodate it, but I never saw any get that factory change. The Skywinder and Redstone come to mind as good candidates.

Doug

ghrocketman
10-09-2006, 08:00 PM
While I now fairly often fly the C11-3, I still find the C5-3 superior to this one also.
Much less weight, high initial thrust spike with a long lower thrust burn.
Plus the C5-3 was much cheaper than the ridiculous pricing of the C11-3.
The C11-3 should be priced no more than $.25/pak higher than the C6-3 or the old C5-3; I mean cmon, an extra ~$2-$3 for a few grams of cardboard....what a joke.

Shreadvector
10-13-2006, 07:23 AM
http://home.flash.net/~samily/stuff/HPR_metric8.pdf



Where exactly is the dividing line between low, mid and high power rocketry?

What started out as a little hobby of mine is starting to grow. I did notice that I have been liking larger (SLS) rockets and even built the LPSLV (over 40" tall).

Is Mid power a designation of size or engine thrust? Will a 20" rocket with an F engine be classified as a Mid power?

Ltvscout
10-13-2006, 07:40 AM
Thanks for the chart, Fred!