Another Rocket Contest Idea

[GL-P]

Anyone like the idea of a contest for highest efficiency???

It could go like this: Altitude/motor ns=efficiency rating
This could generate an increase in high performance techniques

Any ideas that I could add??

 

[jetra2]

I like that idea. Run as a long term contest - people could learn more about where their mistakes and shortfalls are in building and finishing, and constantly up their efficiency rating. Would definately be a good project!

Jason

 

[GL-P]

Yeah, thanks. I think it's all about finese (I think i spelled it right!) over brute force. I'll see if the guys at CAR up here like the idea.

 

[Bill]

Originally posted by GL-P
Anyone like the idea of a contest for highest efficiency???

It could go like this: Altitude/motor ns=efficiency rating
This could generate an increase in high performance techniques

Any ideas that I could add??

How would altitude be measured? Altimeter only? Allow the flyer to opt for tracking by theodolite so as not to penalize smaller models? Require the return of a theodolite tracked model to not penalize the altimeter model?

Allow staging?

This shall be interesting.


Bill

 

[GL-P]

Yep, that makes sense. Allows for smaller models but requires the return of the rocket as to not penalize ones with altimeters who need to get their's back to make an attempt. That's a good one. That would also force the theodolite ones to be bright enough to be tracked.

Staging is a definite yes. The total motor ns covers all motors. Boosted darts would become common place and probably be the top fliers.

Yeah, this could lead to interesting projects...

 

[jetra2]

Would the idea be to get a high efficiency rating or low? By that figure, say you get a 800 foot flight out of a B6. So divide 800 by 5, and you get 160. Then you go and get a 2000 foot flight out of a 120ns G64. That's only a 16.66 rating. Huge difference...maybe I'm not following it clearly, but might there want to be another factor to involve in the process?

Jason

 

[GL-P]

hmmmmm..... yeah, you're right. I ran a G37 24mm just for kicks and rounded down 700ft to 6000ft. Got around 54.

and an M500 got around 2.5.....

I'll think about that.... Give me awhile...

Good you tried it out before I looked like a real big dolt!!!

 

[DynaSoar]

Originally posted by jetra2
I like that idea. Run as a long term contest - people could learn more about where their mistakes and shortfalls are in building and finishing, and constantly up their efficiency rating. Would definately be a good project!

Jason

I am SO into this.

You start with a design, build it, test it, adjust it, repeat until submitted with results.

Give it enough time to run so that people who can't afford to build a new version every month can participate. 6 months? 12 months?

Here's an idea: measure improved efficiency. Final placement depends on both original design efficiency and % improvement. The average of starting place (1st, 2nd, 3rd etc.) and ending place.
(Original efficiency placement + % improved placement / 2).
The winner has to start good and get better.

With the number of variables involved, this would work no matter what class or rocket/motor was used. Different classes might have different variables, but so what?

Radically changing motor type could be allowed, but they'd soon learn that such gross changes result in starting a lot of other considerations from scratch.

Make this a TRF contest? Ask Nick at EMRR if he wants to be involved?

 

[GL-P]

Hmmmmm...... lets say:

alt/ns=rating
5000ft/100ns=50
50ft/1ns=50




alt/ns=rating
800ft/5ns=160
160ft/1ns=160


The only thing I can think of is units......
I asked my dad... meters go with ns......
I tried it again....... same answer no duhhh!!!

Dang rocket science. Never an easy answer.....

I think the fact is that a model rocket goes slower so it has less drag than a more powerful rocket and therefore it actually is more efficient

This is an interesting dynamic..... I guess I'll have an instant advantage....
and the frontal area increases exponentially as the d increases....this should be fun....

 

[GL-P]

I'm liking this a lot. Even this late at night I never expected this kind of reaction... This can allow even kids to get involved because any motor can be used.... I like that improved effiency idea as a dynamic... make take some getting used to and some good planning but it helps grow rocket performance in the hobby. It gives incentive to constantly improve design. Would this improvement be over multiple rocket designs or fine tuning on one rocket???

If there is enough support, how about a group writing to TRA?? I think the contest should be run all year long to give enough time for design. Then there could maybe a running best record on the side as well.

This is shaping up nicely....

 

[GL-P]

Another idea... should there be different motor classes because of the drastic change from LPR to HPR efficiency? It might mix it up a little

Just another idea...

 

[wwattles]

This sounds vaguely like the original idea for "stock" car racing (which has since evolved into NASCAR). Take a standard model that everybody starts with, then allow tweaking in certain areas, and see who outperforms the others.

WW

 

[GL-P]

Yeah, it does. In this case it is an original design. No real general starting place. Do you like the concept?

 

[jflis]

SOunds interesting.

I would however suggest that this be restricted to single stage, single motor, or at the very least single stage.

highly efficient multistage rockets are VERY hard to track and even if tracked, very hard to recover in many areas and, all things considered, a multi staged rockets (with the rules as presented) will be the vehicle of choice in the BP mod roc arena.

Heck, if I am in an area (which I am for the most part) where an A motor in a *very* efficient model is just about the limit of what I can launch and recover, I am prohibited from entering a multi-stage model because I can only get 18mm B boosters and above...

just a thought...

 

[DynaSoar]

Originally posted by GL-P
I'm liking this a lot. Even this late at night I never expected this kind of reaction... This can allow even kids to get involved because any motor can be used.... I like that improved effiency idea as a dynamic... make take some getting used to and some good planning but it helps grow rocket performance in the hobby. It gives incentive to constantly improve design. Would this improvement be over multiple rocket designs or fine tuning on one rocket???

If there is enough support, how about a group writing to TRA?? I think the contest should be run all year long to give enough time for design. Then there could maybe a running best record on the side as well.

This is shaping up nicely....

I agree.

If it can be pulled off a first time/year, it could become a contest type. It could become a subset of R&D. That's what it'd be if it were based on improving efficiency of a given design. I could see NAR adopting it as a contest type. Do your "certifying" flight at a NARAM, have the next year to work on it, do your "improved" flight the next NARAM. Heck, maybe TARC would adpot it. They change their rules every year.

For doing it on TRF, since we can't very well meet, make the first month for submitting a design, 10 for improving, the last month for doing the final flight and submitting.

I've no doubt we could get some sponsors to offer prizes.

But, it'd take having run through it once first.

If it's going to include improved efficiency, people should be recording the design changes and the results. Wouldn't have to be anything complicated or extravagent. Just short journal entries as long as they're accurate. "February 31: Increased fin span from 1.5" to 1.75". Altitude 640 feet. Increase in altitude 15% from start." Not much reason to judge this part except that they do it. After all, it's the learning that's important.

Oh: Certified Engines Only. EX is all fine and good, but let's keep it simple and acceptable to the larger crowd.

I'll help you carry this through. It's just the kind of thing I want to see happen to rocketry. If we just do it with TRF, that'd make it easy, and that's not to say we shouldn't expect more people to join TRF to do this.

Maybe we could ask the mods and owners to make a forum for conducting this? First step is to think through the rules and set them down, so we can set about following the instructions and testing the process. If not, maybe a Google group? Same as yahoo groups but without all the ads.

I'm psyched man. Let's light this candle.

 

[DynaSoar]

Originally posted by jflis
SOunds interesting.

I would however suggest that this be restricted to single stage, single motor, or at the very least single stage.

highly efficient multistage rockets are VERY hard to track and even if tracked, very hard to recover in many areas and, all things considered, a multi staged rockets (with the rules as presented) will be the vehicle of choice in the BP mod roc arena.

Heck, if I am in an area (which I am for the most part) where an A motor in a *very* efficient model is just about the limit of what I can launch and recover, I am prohibited from entering a multi-stage model because I can only get 18mm B boosters and above...

just a thought...

It's a good thought, but this is what measuring for improved efficiency rather than raw efficiency is for. If someone starts with a design they can't handle, they need to start over. We can make recommendations about this so they don't start off on the wrong foot. But every design deserves the chance to be improved on. By not starting from raw efficiency, the absolute altitude and power don't matter.

I don't think it'd be possible to improve a 2 stage as consistently as a single stage. Too much variance in the behavior of staged rockets, unless you're REAL good. I certainly wouldn't start there. But, as I said, measuring improvement levels the field.

 

[GL-P]

For doing it on TRF, since we can't very well meet, make the first month for submitting a design, 10 for improving, the last month for doing the final flight and submitting.

I meant TRA but it would be a good idea to start it small and maybe a subforum for ideas. Thanks, I'll need someone with lots of contacts to get this to work. I also tested a 1/4A which should win every time. I think there should maybe a payload required to be flown. Any ideas to prevent 1/4As from winning everytime?

highly efficient multistage rockets are VERY hard to track and even if tracked, very hard to recover in many areas and, all things considered, a multi staged rockets (with the rules as presented) will be the vehicle of choice in the BP mod roc arena.

How about a boosted dart??? I heard you can get a 20% increase over a conventional optimised model. You'd be getting pretty efficient without adding ns.

 

[DynaSoar]

Originally posted by GL-P


quote:
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For doing it on TRF, since we can't very well meet, make the first month for submitting a design, 10 for improving, the last month for doing the final flight and submitting.
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I meant TRA but it would be a good idea to start it small and maybe a subforum for ideas. Thanks, I'll need someone with lots of contacts to get this to work. I also tested a 1/4A which should win every time. I think there should maybe a payload required to be flown. Any ideas to prevent 1/4As from winning everytime?

I know you said TRA. I didn't mistake that or ignore it. I think it might be wise to keep it not private exactly, but not involve any larger organization as a whole until the idea is tested. I think they'd say the same. Getting individuals from those groups to help out, certainly. The heads of the contest committees from the big groups might be willing to look the idea over and critique it.

I don't "have" a lot of contacts, but I do make them as necessary. I've walked into NASA, FTC, FBI and my congresscritter's office in Washington in order to ask to talk to someone about something on my mind. Once we have an outline of the rules, I'll be glad to contact the contest committee chairs and ask their input.

Will 1/4As really be that much more efficient? I don't know. I think it's an empirical question, or at least one for some extended simulation testing. In any case, improved efficiency is a leveler. If a 1/4A starts out that good and always comes in first place in the first measurement, how much better can it get? Probably not a lot. If the improved efficiency is way down the list in placement, the average between them is going to keep it from winning.

On the other hand, this too is an empirical question. Maybe it CAN be improved a great deal. Each rocket will be a study in R&D methodology and results, and the contest as a whole will also.

I think it might be a good idea to keep this to MPR and below. That way it's something anyone could do, even if some younger participants had to enlist parental permission and supervision (which would be a GOOD thing, IMO). If they're compteing against people with a certification for doing things they can't, they may feel put out and not want to participate.

It'd also be a good idea to have people stick with the same motor they start with, not just the same class. There's lots of Gs, but how many 1/4As are there?

 

[GL-P]

The thing it's hard to get the optimal mass on real small stuff like a 1/4A so it might not be so bad. Oh I just realized it was the average of ranking. Yeah, that should help.

Yeah, keep it below hpr. No bigger than a G.

So where are we at now?:

-Efficiency= Alt in m/total motor ns
-The goal is to have as high as an improvement as possible
-Final placement depends on both original design efficiency and % improvement. The average of starting place (1st, 2nd, 3rd etc.) and ending place.
-the model has to be recovered
-only certified motors are allowed
-altimeters and a theodolite tracking acceptable
-recorded altitude has to be seen and approved by a signing RSO
-year long contest for improvement time

Anything else? This will take some tweaking. Do you want to try this at your club and I'll try it at mine over a six month period once we get some details sorted out?

I love the idea of a yahoo grouo (w/o spam) to post current standings and changes made with altitude change

 

[Rocketjunkie]

Originally posted by GL-P
The thing it's hard to get the optimal mass on real small stuff like a 1/4A so it might not be so bad. Oh I just realized it was the average of ranking. Yeah, that should help.

Yeah, keep it below hpr. No bigger than a G.

So where are we at now?:

-Efficiency= Alt in m/total motor ns
-The goal is to have as high as an improvement as possible
-Final placement depends on both original design efficiency and % improvement. The average of starting place (1st, 2nd, 3rd etc.) and ending place.
-the model has to be recovered
-only certified motors are allowed
-altimeters and a theodolite tracking acceptable
-recorded altitude has to be seen and approved by a signing RSO
-year long contest for improvement time

Anything else?

Classes based on motor diameter. This could allow HPR.
Consider change to efficiency=alt/sqrt(N-s) to reduce the advantage of tiny motors. Otherwise the smallest motor of a diameter would win. Sqrt might need to be another fractional exponent to balance impulse levels.

 

[DynaSoar]

Originally posted by Rocketjunkie
Classes based on motor diameter. This could allow HPR.
Consider change to efficiency=alt/sqrt(N-s) to reduce the advantage of tiny motors. Otherwise the smallest motor of a diameter would win. Sqrt might need to be another fractional exponent to balance impulse levels.

If HPR folks want to do the same, no problem. I just wouldn't want people to be scared away knowing they're competing with "high power" anything. The numbers may even things out in the scoring, but not in the words and thinking of people who don't know HPR. They should be allowed to compete completely without needing any certification of any kind as long as they're either old enough or have an adult supervising.

Would Sqrt be the appropriate scaling factor? Is it even necessary if ranking of basline and ranking of improved performance are averaged?

I need some help with numbers here. My math brain is on vacation.

Also, rather than averaging, would it be better to use an improvement factor scaled to the ranking?:

X = placement (1st, 2nd, 3rd) of baseline/starting efficiency
Y = placement (1st, 2nd, 3rd) of final/ending efficiency

Score = (X - Y / X + Y).

I tried a few sample scores and it looked like the right thing, but I'm just not grokking today. This *was* however the factor that Sam had reversed in the SG-1 episode "Prodigy" where the cadet said it was an error and it was. And it really was; she had it inversed.

 

[GL-P]

This will take some work. It's not on my priority list (school and finishing rockets is), I 'll think about it over the winter and try to stop it from being a 1/4A comp. PM me if you got any good idea. I'll think over equations in my free time (or lack thereof)

 

[GuyNoir]

Originally posted by GL-P
Anyone like the idea of a contest for highest efficiency???

It could go like this: Altitude/motor ns=efficiency rating
This could generate an increase in high performance techniques

Any ideas that I could add??

This used to be an official event for NAR contests. It was called "Design Efficency".

Competitors quickly determined that the best strategy was to fly 1/2A models. Scores were in the 120 and higher range. The event was dropped because it had turned into a version of 1/2A altitude.

 

[Bill]

Originally posted by narprez
This used to be an official event for NAR contests. It was called "Design Efficency".

Competitors quickly determined that the best strategy was to fly 1/2A models. Scores were in the 120 and higher range. The event was dropped because it had turned into a version of 1/2A altitude.

Let's not let this idea die, folks!

I remember hearing about the "Design Efficiency" contest Bunny mentioned. That is why Rocketjunkie is a genius for suggesting dividing by sqrt(impulse) instead the impulse.

To put this into an easily understandable form, dividing by the impulse means that to be competitive, a rocket flying on a particular motor has to go twice as high a one flying on the next lower motor class. For example, to beat the 1/2 A entry, an A powered bird has to fly over twice as high.

Changing the formula to divide by the square root of the impulse, the A model only needs to fly 1.4 times as high as the 1/2 A entry. It now takes two motor levels to require a doubling of the altitude to be competitive.

I culled out the official NAR atltiude records as a rough guide to see how a scaling factor of sqrt(2) would work. Dividing by the square root appears to be workable.

B div	1/4A Altitude	  80m
A div	1/4A Altitude	 148m
T div	1/4A Altitude	 167m
C div	1/4A Altitude	 178m

B div	1/2A Altitude	 149m
A div	1/2A Altitude	 165m
T div	1/2A Altitude	 295m
C div	1/2A Altitude	 305m

A div	A Altitude	 313m
B div	A Altitude	 338m
T div	A Altitude	 442m
C div	A Altitude	 449m

B div	B Altitude	 351m
A div	B Altitude	 510m
C div	B Altitude	 535m
T div	B Altitude	 731m

B div	C Altitude	 340m
T div	C Altitude	 444m
A div	C Altitude	 498m
C div	C Altitude	 756m

B div	D Altitude	 323m
A div	D Altitude	 740m
T div	D Altitude	 880m
C div	D Altitude	1214m

B div	E Altitude	 122m
A div	E Altitude	 330m
C div	E Altitude	1128m
T div	E Altitude	1387m

B div	F Altitude	1430m
C div	F Altitude	1741m
A div	F Altitude	1820m

A div	G Altitude	 640m
C div	G Altitude	1140m

Bill

 

[GL-P]

How does this relate back to efficiency? Sorry but I'm not quite following you Bill. Can you provide a couple samples of efficiency rating with the sqrt?

Thanks. I hopefully want try an efficiency competition

 

[Bill]

Originally posted by GL-P
How does this relate back to efficiency? Sorry but I'm not quite following you Bill. Can you provide a couple samples of efficiency rating with the sqrt?

The original idea was to score the efficiency of each entry by dividing the impulse of the motor(s) used into the altitude achieved.

Several pointed out, quite correctly, that this formula strongly favors smaller motors, 1/2 A to be precise.

Rocketjunkie suggested dividing the altitude by the square root of the total impulse instead of by the impulse might lessen or eliminate this advantage for small motors. I was just posting some figures from NAR altitude records to illustrate that dividing by the square root provides a workable scoring system.


Bill

 

[GL-P]

Okay, I just needed the calc. simplified a little. A little time on wRASP showed that the competition would be a lot closer with sqrt. I calc that a minimum D would have a little advantage but the comp is closer now. Besides, high speed drag would take over on a D rocket. Now is testing on a small scale over a month time period to see if there is some other problems. Do we want to have this start as a TRA comp with a thread for recording scores? The only problem I can see is that smaller clubs at small launches might have trouble getting theodolite tracking setup.

 

[DynaSoar]

Originally posted by GL-P
Okay, I just needed the calc. simplified a little. A little time on wRASP showed that the competition would be a lot closer with sqrt. I calc that a minimum D would have a little advantage but the comp is closer now. Besides, high speed drag would take over on a D rocket. Now is testing on a small scale over a month time period to see if there is some other problems. Do we want to have this start as a TRA comp with a thread for recording scores? The only problem I can see is that smaller clubs at small launches might have trouble getting theodolite tracking setup.

The sqrt works especially well because the power doubles with the classification. (10 D 20 E 40 etc.). It prevents the problem Bunny noted.

Making the final score include improved efficiency does the same thing but more so. Changes the very nature of it, really.

Altimeters should be allowed, theodolites would be the minimum necessary. There are cheap designs available. The specific method and item used should be available for testing/validation for the final scoring. Thus, even a very young person could compete, even if they used a protractor with a weight hung from it. Any altitude scoring will come with variance and that's calculated from the device's design.

 

[Mark Clark]

I came up with this a year or so ago.

https://www.ahpra.org/motorsvolume.htm

Uses a calculation to give a required volume of rocket for each motor depending on impulse and burn time.
Sort of along the lines of what you are talking about. There is a problem with the lowest end motors in but it works out to F's.

Mark

 

[GL-P]

I came up with this a year or so ago.

Cool, that's another idea. You said though that it doesn't work well for smaller motors, right? Something to think about.

Altimeters should be allowed, theodolites would be the minimum necessary. There are cheap designs available. The specific method and item used should be available for testing/validation for the final scoring. Thus, even a very young person could compete, even if they used a protractor with a weight hung from it. Any altitude scoring will come with variance and that's calculated from the device's design.

Okay, I just wanted to see another idea. There is Estes ones too. I agree with that. I wanted to have it so kids could do this too. That's half the fun in some of the best contests. The kids get us to relax and remind us that it's not rocket science.