TARC for All Idea

[AlexBruccoleri]

I had a thought to try adding TARC for all as a major contest event for NAR fliers. I mentored a team in 2003 and the contest was more complex that year, which I really liked. Here is a thought for the rules:

1. Two-stage rocket, two egg payload, max liftoff weight 1 kg, total Ns 120.

2. Score is max altitude and subtract landing distance to a target spot.

3. Fly twice and average score. Rocket and all stages needs to be the same.

This contest would require solid engineering and would have similar optimizations that professional rockets have. Ie, maximize performance with a payload, land safely, land close to a designated landing zone, and be fully re-usable.

I like TARC-size rockets since they are big enough to include interesting electronics, without being too large. An HPR contest would quickly start seeing flights 20,000+ feet and it would be unfeasible for most people.

Maybe we could tweak the rules and have A division be single stage, one egg, B division two stage and two eggs and C/Team be three stages and three eggs.

Cheers, Alex

 

[James Duffy]

Alex,

"TARC for all" is about to become a reality. The 2023 FAI World Championships will be held in the US, and one of the events will be a precision altitude/precision duration event with a fragile payload (an egg). In short, a metric version of TARC, with a 300 meter target altitude, a 60 second target duration, one egg, and three flights.

Look for the S2/P event in the FAI rulebook. Like all FAI events at the World Championship level there will be separate Junior and Senior divisions. We would love to see you back on the team. Maybe you'll win another medal?

James

 

[AlexBruccoleri]

Hi James, Nice to hear from you on the forum! We should catch up sometime offline.

I was not aware of the S2/P event and I looked it up. Very cool! My contest idea would be a bit different in that precision would only be part of the landing. Max altitude would be the other parameter. Maximizing altitude while minimizing landing distance are more realistic and relevant than precision altitude/duration, in my opinion. The current TARC rules make sense for smaller launch sites, which is important for having lots of entries.

Another reason I like "mid power" rockets for contest is the motors. There are a lot more motors to pick from in the 18-29 mm range than 13 mm. The contest should be more interesting.

Cheers, Alex

 

[boatgeek]

I think that if you're trying to make this a widely accessible contest, you'd need to take the 2-stage requirement out. That will essentially require that the flier use composite motors and therefore staging electronics, since it's going to be hard to fit two F15 motors and two eggs under the max liftoff weight of the F15-0.

I like the TARC rules in general as encouraging precision and repeatability rather than the luck of the draw you'd get with max altitude and minimum landing distance. Those goals also would heavily favor higher altitude and lower wind flying sites. If you want to encourage people to optimize their rockets, you could add the motor impulse to the TARC-style scoring. That would push flyers towards lighter and less draggy rockets.

 

[AlexBruccoleri]

@boatgeek - Two stage rockets with electronics and two eggs can easily be under 2.2 pounds. I have built similar rockets and it was not that hard. To maximize altitude I would expect fliers to be much lower.

Also regarding luck, maximizing altitude is good engineering. I would argue the precision altitude/duration has a bigger luck element. Though in both my idea and TARC, flying more than once reduces the luck element.

I am concerned about luck with precision landing, specifically regarding wind. I recommend having a morning and afternoon flight window. Each flight would need to be in the twos window to average the weather. That being said, hopefully the altitude would be the dominant factor. The landing score is there to keep the rockets on the field and give credit for designs to reduce drift.

Cheers, Alex

 

[cerving]

A few years ago at LDRS, TCC had a 3000' in 300 seconds contest, the payload was a 12 oz soda can. It was challenging... 300 seconds is a long time for such a relatively low altitude.

 

[boatgeek]

@boatgeek - Two stage rockets with electronics and two eggs can easily be under 2.2 pounds. I have built similar rockets and it was not that hard. To maximize altitude I would expect fliers to be much lower.

Also regarding luck, maximizing altitude is good engineering. I would argue the precision altitude/duration has a bigger luck element. Though in both my idea and TARC, flying more than once reduces the luck element.

I am concerned about luck with precision landing, specifically regarding wind. I recommend having a morning and afternoon flight window. Each flight would need to be in the twos window to average the weather. That being said, hopefully the altitude would be the dominant factor. The landing score is there to keep the rockets on the field and give credit for designs to reduce drift.

Cheers, Alex

Oh, I definitely could see how to do this with electronics and composite motors. I'm just saying that the rules as written would functionally require that approach, so anyone who wanted to stick with direct-staged BP motors would have a hard time competing. They'd be limited to a ~550 gram liftoff weight, of which 200 would be taken up by 2 F15 motors and 120 more by the eggs themselves. A single-stage project would be much more accessible to people who don't already have flight computers that can do airstarts.

 

[AlexBruccoleri]

@boatgeek - One could cluster black powder motors in the first stage. Some fliers did that in the 2003 TARC. That being said, I doubt anyone would win via BP motors. Also there are plenty of timers available for staging that are small and inexpensive. The idea behind this contest is to blend the complexity of HPR rockets with contest rocketry, while keeping the size small enough for a lot of launch sites.

Cheers, Alex

 

[boatgeek]

I ran a super quick and dirty simulation of a F-F 2 stage with 24mm motors. If gave me 5600' for an F32->F32 (all AT single use) and 5500' for an F44->F30 (AT SU to CTI reload). I didn't get all of the weight in, so it's likely a little heavier than I simmed, but I also didn't optimize the fins much. I'd guess that a good builder could get 5000-6000 feet. That's pretty high for a general audience competition since many people can't fly that high at their home fields.

 

[AlexBruccoleri]

@boatgeek - That is a good point. 120 Ns might be too much. Maybe 60 is better to start. One thought is to have 60 Ns for qualifying and then 120 for a national final.

cheers, Alex

 

[Ez2cDave]

1. Two-stage rocket, two egg payload, max liftoff weight 1 kg, total Ns 120.

Aerotech F50T staged to an Aerotech E15W . . . Or an Aerotech F25W staged to an Aerotech E15W . . . Rock & Roll !

Dave F.