F3A--Electric.

[Bjorn Lehnardt]

Jason is getting a fair bit of his 93db from the belt reduction drive, no?

----- Original Message ----- 
From: "Troy Newman" <troy_newman at msn.com>
To: <discussion at nsrca.org>
Sent: Friday, August 08, 2003 8:08 PM
Subject: Re:F3A--Electric.


Nope weighed with batteries in it....

FAI sporting code is available via the NSRCA website and other locations...
It has the rules regarding the event of F3A...Continues to Surprise me how
few read the FAI sporting code rules for F3A...they are shorter than the AMA
rule book

In some cases the Battery pack is the flight pack also....therefore you
don't weigh a model without its flight pack....This is a challenge in
Electric F3A models because the batteries are the weight....There are not
many full blown 2M models that will make weight on a full tank of fuel....

Yet the Electric model takes off at under 5kg and flies the entire flight at
under 5kg...and lands at under 5kg....Adds a little to the consistency mark
eh?


Also some have claimed its silent flight....Tony said the sound meter was
tipping 93db(A)...That means prop noise is our greatest noise issue....Who
cares about in flight noise...the Sound meter is 3M away from the model....

Just some FYI.....YS 140DZ turning a 17-12 at 7800rpm is 92-93db(A)...OS
140RX same 17-12 at 7800rpm is the same 92-93db(A) this is roughly 394mph
tip speed....

Jason is using a 22" prop at around 6000rpm its hit 93db(A) and if you
calculate the tip speed its 392mph.

So guess what prop noise is the kicker....its not silent flight when you are
tested at 3meters.

This being said I think this is some cool stuff and has some real
possibilities...servo pots that last 200-300-400 flights....Airframe
vibration is less(still some due to the prop)...can't really build models
much light with the electrics....as they still need to stand up tot he
flight loads....I mean how much lighter are you going to build the
wing?....Firewalls still need to hold the motors and the thrust loads....Yes
you can trade pipes, Hyde mounts, and fuel tanks...but you gain the battery
system....


its all very new stuff....Its neat to see someone sticking his neck out. I
wish I had the Brass ones to do it!

TN


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