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Old Jul 22, 2009, 02:10 AM
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F5B turns

We do anticipate the turns in F5B, more than in F5D. The reason is that a turn in F5B incurs no statutary penalty, IN F5D it is 200 points I think which wrecks the round. In F5B you can, and some people often do (Remo and Rudi), win the round with a cut.
The reason is simple. A cut requires the good pilot to do a circle. Assume the diameter is 30 m, so you lose 100m distance because of the cut. But we do 40 turns in F5B. If you do 1.25 metres to long a leg you also lose 100m in a round because if you go 1.25 m too long you have to do anorther 1.25m additional to get back and that 40 times is 100m.
In Base B 5m too long is common, 2-3 on base A. If by risking a cut you can reduce this by a couple of metres you are gaining. Rudi always used to cut, reducing the length by a metre or two each leg until he cut, then going back out a metre or so.
As Chuck said, if nothing ever breaks you are not pushing hard enough.
If you never cut you are either a genius or are flying too long.
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Old Jul 22, 2009, 05:12 PM
Needs to do 52 legs !!
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Verenigd Koninkrijk, Fareham
Joined Aug 2008
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Lets put it another way. If you don't anticipate the turn you are never going to fly more then 40-42 legs. When you do start to anticipate them there is no more big difference between the heavy or light model.

Today i flew the B1T in medium to heavy wind (20-25knots) and managed 44 legs twice on the light 460 gram pack. I put in 120 grams more and did 45 legs. Sure it could be that the distance on the legs is not correct since there was no base B buzzer. Personally i think it was the extra weight that offset the effect of the wind.
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Old Jul 23, 2009, 12:07 AM
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Quote:
Originally Posted by jjmouris
....................
Personally i think it was the extra weight that offset the effect of the wind.
+1
I have seen same effects. Till the wind is 3-5 m/s, lighter is better. But heavy model is more stable on stright in the windy condition. And not so much faster (jast looks like) but laps count remain the same.
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Old Jul 23, 2009, 01:09 AM
The props of tomorrow
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What setup is in the B1T Joe ?
What is this 460gr light pack ?
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Old Jul 23, 2009, 03:51 AM
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watt.minutes used

How many watt.minutes did the 45 legs use Joe?
Compared with the 44 at 120gms lighter.
If you use my program you can examine the watt.minutes used over any part of the flight, in particular for any sequence of four or six legs. This is useful to compare the effect of weight, prop, height management.
Note that if you are going to do 48 legs then you cannot afford more than 30 watt.minutes per leg, 120 for a sequence of four, 180 for a sequence of six. This gives 1440 for the legs, say 60 for the launch, leaving 250 for the duration, a bit tight in many cases.
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Old Jul 23, 2009, 04:57 AM
Needs to do 52 legs !!
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Georgi, if i tell you i will have to kill you.

George, i don't know the W.min used but i did the full task and landed on 11 minutes, there was no thermal action to speak off.

I think 48 is a little to much to hope for under these conditions, my flying and the not so nice anymore plane i am flying.
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Old Jul 23, 2009, 11:57 AM
The props of tomorrow
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Quote:
Originally Posted by jjmouris
Georgi, if i tell you i will have to kill you.

Haha funny guy.Is a nuclear reactor rotating inside ?
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Old Sep 05, 2009, 05:34 PM
Needs to do 52 legs !!
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So back to this old discussion.

At the Nats i flew 2 rounds with the light pack and managed 41 and 40 with a motor on in both. There was a lot of wind so i decided to change tactics and went for the heavy pack. The result was a 43 legger. Coincidence?!

Also, Thunder Power is coming out with a 45C continues range now. If i wasn't strugling already to get setups together that have ~30 seconds run time, this really is going to blow the cap of everything i've got or was planning. Oh well, back to the drawing board.

Joe
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Old Sep 05, 2009, 08:54 PM
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Quote:
At the Nats i flew 2 rounds with the light pack and managed 41 and 40 with a motor on in both. There was a lot of wind so i decided to change tactics and went for the heavy pack. The result was a 43 legger. Coincidence?!
I have notice that most people judge the climb by finishing at a desired height. With a heavier model this might mean more motor time than the light model. with the light model It may be necessary to climb more and also climb more on the 1st leg.
However we all have to find a technique which best suits us and for you the heavier model might work better.
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Old Sep 06, 2009, 10:57 AM
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With a given amount of energy, say 120 watt.minutes, a lighter plane will be going faster than a heavier plane, so the the proportional effect of a 15 m/s head wind like we had at the Nationals is less. In fact if you have a very heavy plane that only accelerates to the wind speed you will never get to Base B!

On the other hand if you have a light plane with no penetration no amount of height will get you to base B. I know because I was flying such a plane two days earlier. Alan suggested I land backwards and I tried b ut it ended in a cartwheel.

Almost all of us had one round where we ran out of motor. The lighter plane helps with the duration task.

Then there is the energy lost to induced drag a lot in the turns and a little in the straights. This goes up with weight.

I flew a plane at 1460 gms for all four rounds, 1000gm Avionik and 460gm battery.
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Old Sep 06, 2009, 11:40 AM
Needs to do 52 legs !!
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George, that was on 5S Lipo? So my guess 5S 3200mah Overlander?

I found the 6S 460 gram packs to not last very long at sub 30 second setups and not even reliable at just over 30 seconds run time.

The power would actually drop huge amounts at the end of the climb mostly in the last sets and specially during a 6 leg climb.

We will see what the next generation is like, but my money is on that this is a capacity problem and has nothing to do with IR.

Joe
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Old Sep 06, 2009, 11:47 AM
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That is correct, 5S 3200 Overlander Fullymax. Same pack all four rounds. Mark also flew these I believe. I have maybe 10 flights on it.
The capacity used on 5S is about 2000mAh.
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Old Sep 06, 2009, 04:49 PM
The props of tomorrow
Varna , Bulgaria
Joined Feb 2007
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Hello guys , just to share about batts.
I have 2 lipo packs of the 35/70 C NeuEnergy 4S 4100mAh.
They gives me the one 29 secs of motor the other 34 secs.
So in my case is always good to have 2-3 packs of same brand to select the best.
So considering the Germans are using 4S setups with success I'm going their way.
mAh used on 4S at average power 3600w/mins - 2300 mAh.

Hope sharing will make the results going up.

Georgi
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Old Sep 06, 2009, 05:01 PM
Needs to do 52 legs !!
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Georgi, i think you might have one bad battery.

I have never seen any power or run time difference between two battery's of the same type.

Joe
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Old Sep 06, 2009, 05:36 PM
The props of tomorrow
Varna , Bulgaria
Joined Feb 2007
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The batteries on market now are not so good.If i didn't purchase these 2 pack I was able to get an 40/80/120 C rate pack 5000mAh with an IR 2 times lower ... but I wouldn't be able to change from a 3kw to 6-7kw with an limiter ...

ll'be ready for next season.
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