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Author Topic: Bar Fly Legal Eagle  (Read 5890 times)
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Skymon
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« Reply #25 on: January 23, 2018, 07:41:28 AM »

John
I read that these cabin type models fly right hand circles.
My other indoor stick stuff flies left, so I was expecting that to continue.
My feeling with this one was just let it go and what ever way it goes, adjust that circle...
I wonder if precession effect has any bearing on the turn direction.... with such big indoor props there has to be a resultant from that torque up front.

Many thanks for the kind comments, I'm relatively new to indoor, having returned to aeromodelling after a long lay off.

I'm really enjoying the whole precision of it all.

Best regards
Si
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piecost
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« Reply #26 on: January 23, 2018, 08:45:43 AM »

Thanks for the compliment John. The model should really fly well at that weight. My 3g models were so much better performing than my 3.4g example. A positive snowball effect I suppose.

With regard to circuit direction; we found that with LH circuits Legal Eagle models struggled to take off or even landed again with high turns and torque. Circling with torque tended to keep the model Earthbound. RH circuits gave more consistent, steeper initial climbs.

The circuit direction for stick models is critical in that the stick twisting causes wing warp to aid trim after launch.

With these full fuselage models this effect is not present. But the RoG introduces different limitations. Lots of torque is needed to take off (more than for a hand launch) but if you give too much the model may stall, torque roll and crash as its stability cannot overcome the destabilising effect of the propeller.
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Skymon
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« Reply #27 on: January 23, 2018, 09:47:11 AM »

Interesting info - I'll soak my stab off and add a bit of RH to start the turn.
Does stab tilt work as effectively on this type of model too?

What torque are you launching at?
I measure in g/cm, but I can easily convert Smiley

Looking at my calendar I think the 6th March will be my next session indoors.
I'm hoping to have a go with this model then.

Best regards
S

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piecost
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« Reply #28 on: January 23, 2018, 01:13:37 PM »

I employed 1/3rd partial motors under a 25' ceiling to simulate the over 50' height of the Brabazon hanger. Post 7 and 8 gives the motor and turns. I do not use a torque meter,  though it is a good idea. Scaling the torque from data obtained from testing gives me a launch torque of 11g.cm. This would put my model through the roof of a low ceiling site. Perhaps you could try motors ranging from 1.6g/m to 2.0g/m in loops from 22 to 24 inches.

I must try a full motor under the low ceiling
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Skymon
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« Reply #29 on: January 24, 2018, 06:24:13 AM »

Piecost
Was your 8" loop a 1/3rd motor??
SO a full one would be 24"?


Regards
S
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piecost
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« Reply #30 on: January 24, 2018, 06:32:48 AM »

Yes
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Skymon
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« Reply #31 on: March 07, 2018, 03:54:05 AM »

So... I had a go with the bar fly...
Not a great success.

Winding.
Well, that was different. I need some sort of yoke to hold the rear peg when I wind.
I'd not really thought about that so I didn't have one.
This meant I sort of jammed the plane on the build box by the rear stab post.
That broke off. Hastily reglued

Then I asked another flier if I could borrow their nice little yoke plate with pin that went through the rear peg.
That did work.

I wound on a few turns - 500 and let it go.
It stalled massively again and again.
I tried to adjust the tail incidence and where I'd hastily repaired it earlier, the tissue tube was now attached to it quite firmly Sad

I did manage to move it. I had a few turns left and let it go.
A floundering level flight followed by a power dive.
NO real indication that there would be any sort of turn either.

Some work to do I think  Smiley

Task list:
1 - Repair the stab rear post and tube.
2 - build a yoke and pin stooge to allow me to wind it up without breaking stuff
3 - decide on a motor size
4 - have another go.

I'll update when I get the chance to get it in the air again.
On the positive side there were a number of LE's flying beautifully around the Wickham community centre last night.
That sight really inspires me to get mine in the air.


Happy flying
S

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piecost
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« Reply #32 on: March 07, 2018, 09:25:14 AM »

Sorry to hear of your troubles. I used some fin offset to get a right turn. Also, a bit of fiddling with the thrustline. I recommend that you consider a blast tube to protect the delicate structure during winding. My first wind at the nats burst the motor on low turns.
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piecost
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« Reply #33 on: March 28, 2018, 04:12:08 PM »

Experiments with stability and tail sizing on the thread:

Re: How do WS planes with "aft CG" fly at all???

http://www.hippocketaeronautics.com/hpa_forum/index.php?topic=23088.0
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piecost
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« Reply #34 on: March 28, 2018, 04:19:25 PM »

The new fuselage of the bis 4 version has the wing mounted 20mm further forward and 4 longerons back to the peg tapering to 3 longerons at the back. I was happy to find that I could cover it in Esaki without huge wrinkles and that the fin/tailplane post was still attached rigidly enough.
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Re: Bar Fly Legal Eagle
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