Scores Discussion

[builderguy135]

Scores from the Cobra Invitational:
1. 55.78
2. 50.21
3. 43.35
4. 39.63
5. 37.21
6. 35.38

I don't know what the ceiling height was.

That's about 16 sec/flight. ELG was held in the gym (from website) so I'd estimate about 22-26'.

[builderguy135]

What times have everyone been getting recently?

[Kai0721]

What times have everyone been getting recently?

Not the best but I have been averaging about 12 sec flights in a 25 ft ceiling my highest has been about 16 seconds.

[Jdh3]

20 seconds in 25 feet (actual flight height was closer to 22 feet)

Video here:
https://youtu.be/wI_GzT1dfuE

[bjt4888]

Jdh3,

Nice flight.

Brian T

[Jdh3]

Jdh3,

Nice flight.

Brian T

Thanks, the more recent practice had them hitting 1.0 seconds / ft. They are still improving and have 3 weeks until regionals.

[bjt4888]

1 second per foot is very good. Probably your team is already on this track, but study of the following may help push to 1.1 and 1.2 seconds per foot:

1. Hip Pocket Aeronautics, Bill Gowen “WIF 7” design and forum thread.
2. AMAGlider website, Kurt Krempertz “Time Machine” design and narrative on this website and current National AMA Champion glider plan for 45 ft ceiling.
3. Yashinsky (sp?) F1N designs and other, see “Everything About F1N” Facebook page
4. If you like my design “ELG for 2014”, plan on Hip Pocket Aero, another possibility; design ideas borrowed from Stan, Kurt, Bill, Lee, Bob, and many others, plus ideas of my own. Getting 1.1 - 1.15 seconds per foot pretty consistently; 28.5 - 29.8 under a 27 ft ceiling; needs wing to be scaled up to 30 cm and weight up to 3.5g.

Brian T

[Maxout]

I'd be extremely hesitant to compare these models to an F1N or even an AMA glider. The trimming techniques are somewhat similar, but the wingloadings on ELG in 2019 are vastly higher than AMA/FAI models. Also, F1N has no span limit, and this makes the trimming somewhat different. Since I fly literally every indoor glider class there is, I've seen the differences, and they can be stark. The trimming differences are less of an issue though.

Things that are similar: the flaps act the same. Adding left aileron trim at the tips still works in reverse, and twisting the wing at the root still works the way it's actually supposed to. And the models still require a forward CG and lots of indicence.

In high ceiling contests, ELG drifts toward conventional AMA Standard Class gliders like the WOW. My Carbonette ELG design is an example of that.

The lack of a chord limit is slowly being exploited and it makes a big difference. The lower aspect ratio wings are less efficient but stall softer and offer a lower wingloading, which makes snappy glide transitions much easier. To my knowledge the only published wide chord design is the Super Protege, but hopefully there are others I've missed. Also take a look at the European F1N-150 designs. Super Protege is a direct upscale of one of those. Ironically, the F1N-150s fly longer despite being smaller. Wingloading really is king.

In terms of flight times, I get 19-20 seconds under a 24' ceiling (roof peak is 26' and I can safely transition at 25') with stock Proteges and 23-24 seconds with the Super Protege. My best times with the Guru glider were in the 15-16 second range under a 22' ceiling, but it wasn't my model and I didn't spend much time flying it.

[DatSciolyBoi]

I was able to get 1st at regionals with a glider that lasted about 20 seconds so maybe 0.9-1 second per foot

[Maxout]

I was able to get 1st at regionals with a glider that lasted about 20 seconds so maybe 0.9-1 second per foot

You have to factor in time spend in climb and transition too. So, for example, 26 seconds in a 25' ceiling would still equate to over 1 ft/sec since the model will spend about 1.5 seconds climbing and transitioning before it actually starts gliding.