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Re: Flight B/C

Posted: April 11th, 2023, 4:00 am
by randomdogonapc
Ok, thanks for all the advice. I’ll test the new rubber and see if it’s worth using compared to my current setup(and check my math again).

Re: Flight B/C

Posted: April 11th, 2023, 2:18 pm
by pumptato-cat
jander14indoor wrote: April 10th, 2023, 10:22 pm A nice side benefit for SO, since you typically fly with defined rubber motor mass, knowing the linear density of your pre-cut motors makes it easy to make up a new motor close to the correct mass. Just back calculate from linear density to length for say 2.0 g and cut your motor accordingly. Maybe slightly long, but not much, and then trim to exact weight. Saves a lot of wasted rubber, and a lot of time.

Jeff Anderson
Livonia, MI
Hey, can you elaborate on how you "back calculate form linear density"? Currently, I'm cutting blanks of 1.9g and calculating density before tying knots to estimate(I don't have enough o-rings otherwise), and I probably have a 1/5 chance of getting the density I need... Wondering if you do a different method(I don't own a rubber stripper though).

Re: Flight B/C

Posted: April 11th, 2023, 4:21 pm
by coachchuckaahs
Cat:

Jeff is simply saying you can calculate a length to cut to get your target mass. For example, lets say you have a piece of rubber that is 35" long, and the mass is 2.6g. The density is 0.0674g/in. Lets say your o-rings are 0.015g each, for 0.030g, and your target mass is 1.995g. Then your target rubber mass is 1.965g, and at 0.0674g/in this is 29.14". So, carefully cut your rubber to this length, slip on the two o-rings, use one of the "zero loss" tying methods, and you should have a loop with o-rings at 1.995g. Note: After breaking in, and wiping down, your rubber will probably be 10-20mg lighter. (Note: your o-rings may differ in weight, this is a hypothetical number)

Rubber motor tying without trimming can be seen here: https://youtu.be/5u4ghL21ij8

Note also that rubber will vary in linear density along its length. So I would cut maybe half an inch long, and then trim down while hanging from a mg scale until you hit your rubber target weight. I always make a wire hanger to hang the rubber under the scale. I have found putting it in a cup or pan on top of the scale can impact scale readings substantially (even over 1/2g) if the rubber was just cut or just wiped (static electricity).

Coach Chuck

Re: Flight B/C

Posted: April 17th, 2023, 9:58 am
by randomdogonapc
Hi!
Now that a lot of regionals and all invites are over, I was wondering if anyone is willing to share flight times from your competitions. I’ll start.
Central Ohio Regional the top flight time was a 2:43 Div C and a 2:06 Div B (Ceiling 53 feet but only flyable 45-42 ish feet)
West Liberty Invite the top div B flight time was a 2:46 Div B(Ceiling 28ft)

Re: Flight B/C

Posted: April 17th, 2023, 10:27 am
by Banana2020
Southwest Pennsylvania Regional(16ft ceiling, AC on, conference room) won by a 1:55 flight in Div B and I think 1:30 in Div C.

Re: Flight B/C

Posted: April 17th, 2023, 10:44 am
by pumptato-cat
randomdogonapc wrote: April 17th, 2023, 9:58 am Hi!
Now that a lot of regionals and all invites are over, I was wondering if anyone is willing to share flight times from your competitions. I’ll start.
Central Ohio Regional the top flight time was a 2:43 Div C and a 2:06 Div B (Ceiling 53 feet but only flyable 45-42 ish feet)
West Liberty Invite the top div B flight time was a 2:46 Div B(Ceiling 28ft)
Was AC on for any of these competitions?
Also, thank you so much for this information! It's very helpful, as I haven't gone to my State competition and am very stressed.

Re: Flight B/C

Posted: April 17th, 2023, 11:41 am
by randomdogonapc
pumptato-cat wrote: April 17th, 2023, 10:44 am
Was AC on for any of these competitions?
Also, thank you so much for this information! It's very helpful, as I haven't gone to my State competition and am very stressed.
Nope!

Re: Flight B/C

Posted: April 18th, 2023, 9:55 am
by randomdogonapc
Hi,
So I went flying again today and the wire on my torque meter slipped out of where it was held. I’m using the J&H torque meter, which secures the torque by threading it through two holes in the back. The wire is all bent now. I’m pretty sure it should still work, but not entirely. I can fix the issue with the torque wire slipping, but will a bent torque wire still show the same results?

Re: Flight B/C

Posted: April 18th, 2023, 10:14 am
by pumptato-cat
If it helps at all, my FF wire is curved and I haven't noticed a difference in flight.

Re: Flight B/C

Posted: May 5th, 2023, 11:16 pm
by jander14indoor
Well, with SciOly being down for a while, I wasn't able to share the MI state tournament results. So, here we go:
Div B (where I was ES):
Winning time 3:13.5 by MacDonald MS
Second Place 2:39.5 by Meads Mill MS (heading to national tournament)
Third Place 2:38.3 by Clague MS (heading to national tournament)
Two other teams over two minutes
Nine teams between one and two minutes
41 total teams
Only a few teams tiered, again, oversize boxes.
Many partial logs, biggest reason was units!!
AC was on, but you could fly between the events if you set up you plane for a small enough circle and launched in correct spots. Noticeable, but not the worst flying conditions I've seen.


Div C:
Winning time 2:45.3 by East Lansing HS
Second Place 2:29.2 by Holt HS
Third Place 2:12.1 by Novi HS (heading to national tournament)
Five other teams above two minutes
Seventeen teams between one and two minutes
41 total teams

Jeff Anderson
Livonia, MI