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Feb 20, 2019, 12:13 PM
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Quote:
Originally Posted by piano0412
I got two more questions. What is "wing reflex"? Why do you regard the A-4 as delta wing? A delta wing doesn't have elevators at all - the A-4 does have elevators
Maybe you should take these aerodynamics discussions somewhere else. This thread is about the FW A-4, yes a delta winged plane with elevators.

Aerodynamic properties of swept and delta wings have been discussed since the 40's and are well established, believe me. The A-4's delta wing is no exception to it

See here (and in a million other) articles :

https://en.wikipedia.org/wiki/Delta_wing

https://en.wikipedia.org/wiki/List_o...-wing_aircraft

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Last edited by Herb; Feb 20, 2019 at 12:54 PM.
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Feb 20, 2019, 05:32 PM
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Quote:
Originally Posted by Herb
That sounds like complete nonsense. Most likely his CG was too far aft or some other flying mistake, and that was probably the reason why he crashed.

It is not unusual for people to sometimes construct improbable aerodynamic theories about why they did crash a plane ...

Btw I flew the A-4 with and without cheater hole, and there was absolutely no trim change, or any of the above nonsense effect.

I've had innumerable flights with mine, takes off by itself, easy to fly and land with the right CG and throws - many videos of mine here :

https://www.youtube.com/playlist?lis...Z-sLC9_6QB1tix

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That‘s what I had expected. Thanks for proving me right
Feb 21, 2019, 07:10 AM
EDF Vulcan To The Sky
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Last edited by Radar-Guy; Feb 22, 2019 at 01:10 AM.
Feb 22, 2019, 08:03 AM
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Quote:
Originally Posted by Herb
Indications about the correct CG are quite confusing, since it's unclear from where exactly the CG is measured.

The included manual instructions are nearly illegible regarding the CG, but this update is more helpful and understandable:

https://www.motionrc.com/pages/produ...df-a-4-skyhawk

In any case it seems mine will need lead in the nose - unless I fly with at 6000> pack...

EDIT : my latest CG is at ~"190mm" gear up, which places it just ahead of the red mark below (and ~ 5mm ahead of the "195mm" mark in the update), and right on the yellow pin.

.
Herb, do you still fly her with CG @190 mm, also with closed cheater hole? Do you have some lead in the nose?
Feb 23, 2019, 01:51 PM
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Thread OP
My CG is given in post 58 above ...
Feb 23, 2019, 02:30 PM
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Thank you for confirmation!
Feb 28, 2019, 02:35 AM
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piano0412's Avatar
Another question, Herb: I really like your scheme… where did you get the decals? Having looked at Callie's web site, I haven't found this scheme's decals yet.
Feb 28, 2019, 04:21 PM
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How about reading post no. 27 ?
Mar 01, 2019, 10:31 AM
Registered User
piano0412's Avatar
Looks like I need new glasses… I had seen neither the decals @Callie nor post No. 27

Thank you for your patience!
Mar 04, 2019, 01:38 PM
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Took off from fresh short cut grass yesterday ... seems to be doing ok as soon as that small nose gear gest off the ground.

The reduced weight on the nose gear seems to help, on mine the CG is such that it sits very light on the nose gear. The mains wheel are quite large in comparison, which I think helps a lot !
Mar 04, 2019, 11:45 PM
Vertical Unlimited
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I have been similarly impressed by my A4's ability to handle relatively long grass. I similarly balance quite "aft" and this helps with rotation, which in turn reduces the load on the mains as the wing begins to "fly". The large main wheels sure help.
Mar 06, 2019, 07:34 PM
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Thread OP
I agree !
Mar 08, 2019, 08:57 AM
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Herb, I read that you are very happy with the FMS fan. Do you also have the FMS 70mm fan in service? I am looking for a replacement in my Dynam Me262 as I don't like the screaming of the 5-blade fans, and therefore I would be interested in the FMS fans. What ESC is needed for the 6S version? Could I reuse the Dynam ESCs if I take the 4S version? I haven't found any specs so far.
Mar 09, 2019, 12:58 PM
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The Dynam Me-262 esc's will do 6S ... It's printed on the cover ?

Several people at my field have put 6S inrunner fans in the Dynam Me-262 with stock esc, I think they put Freewing outrunner fans that they had lying around.

Yes I have several FMS fans, including the 70mm (x2), and they are excellent, significantly better design than the Freewing one (lighter, more efficient, better quality inrunner motor, good price) :

https://www.rcgroups.com/forums/show...EDF-fan&pp=100

https://www.rcgroups.com/forums/show...df-70mm&pp=100
Mar 10, 2019, 12:55 PM
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Thread OP
The A-4 Skyhawk in good company,

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