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Old Apr 23, 2015, 06:38 AM
BuBu2 is offline
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Quote:
Originally Posted by brolley View Post
You can make a hole in the foam in front of the motor. Then cut a plastic spoon in half and glue that piece over the hole if you have room. Kinda makes a scoop to catch some air and direct it into the motor.
Exxxcellent idea! Thanks for the suggestion
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Old Apr 26, 2015, 04:41 PM
hongkong is offline
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der gerne zweimal billig kauft
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Germany, BW, Stuttgart
Joined Mar 2012
36 Posts
Hi Folks,

First 10 flights are done... Thanx to the members of the groups I got it in the air finally.
As I am a beginner, the plane does not look like it did last year

Still didnīt get the hang out of how to throw / launch. Without a slight head wind its almost impossible and if the wind ist too fast, the plane is spinning at the start from the motor torque because it canīt gain speed quick enough.

Once in the Air it flies very smooth. Very controllable. Landing is easy.

But what is really confusing: With the elevons in line with the wing (even, neutral position) the plane always wants to got down and I have to pull all the time. So I trimed them for a straigt flight and now they are 3mm up. CG is 400mm.
Should I move the LiPo even more backwards???
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Old Apr 27, 2015, 09:14 PM
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I would say that you CAN move the lipo more rearwards a bit, BUT there will be issues.....
To keep the 'death spiral' effect, that it seems all flying wings can have, you need to be a bit nose heavy.
Flying Wings "like" a bit of Reflex too - that is where the trailing edge is UPWARDS a bit. So this is what having Up trim does.... and it seems the Radjet has none as it comes, but this is what Full Length Elevons can allow you to do easily. (maybe they say have that in the manual? I forget!)

3mm is not too bad, maybe a fraction too much. I have about 2mm and I can't MAKE mine death spiral if I want to! So that is GOOD.
Mind you, mine (te currently flown one out of two) is a 4S HEAVIER Radjet, so that would NEED more Up Trim anyway. More AUW needs more Angle Of Attack to fly along level, thus more Up Trim than a lighter one.

But anyway, about 2mm is good.... so you could move your battery rearwards a BIT it would seem.
You won't tell much difference at all in the flying, but IF it stalls and is more than X amount rearwards CoFG, then it can enter the death spiral. So the CofG setting is more about keeping it away from that possibility, than for any other aspect.

For your LAUNCHES..... throw it with a bit a bit steeper climb AND with a rightwards tilt. Maybe 10deg to 15deg for a start, to see what YOURS does. Still throw it dead straight head of course, ONLY a right tilt added.
I can't know how strong you throw it, but it is a small plane, with good hand hold, so you should have no issue giving it a good 'human' powered launch.
Use more HUMAN power than Motor power.... about 2/3rds Throttle upwards the torque becomes more notable, so typically 2/3 to 3/4 Throttle is enough at the LAUNCH. Increase after that if need be. But to learn how much of each of those to energy sources to use, lean towards what you are doing now and then swing the balance a bit more to the throw energy, until you see it is a good result every launch. That is because at least NOW you are getting it flying, not crashing on launch! So start from there and IMPROVE it step by step.
Yes, into wind always HELPS - but as long as your method is good for no wind, then it will work for ALL cases.
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Old Apr 29, 2015, 04:43 PM
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der gerne zweimal billig kauft
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Joined Mar 2012
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Hi Peter,

thanx a lot for your helping. I acted upon your advice and experienced two things.

1. Pushing back the battery resulted in elevons 2mm up. But as you sad. I noticed no difference in flight behaviour. I will leave it like that untill I try heavier and more powerfull batteries.

2. Giving a small tilt rightwards when throwing did help a lot to counteract the tendency to spin leftwards. That said, it is possible to apply more throttle. I always used only about 40% of the stick travel - but that means nothing as the very cheap ESC is not very linear.

Iīm very glad as it is now. No need for mods in the near future.

michael
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