I guess you missed the bit below the video "
Prototypeneinbau die Rumpfspalten verschwinden in der Serie natürlich"
Means "single prototype, the gaps will naturally
disappear in series production."
Google translate would have told you that too but
you have to know you need to use it, I guess.
In any case on the contracting part of the
fuselage like that the flow is turbulent and the
boundary layer is fairly thick.
The boundary layer is defined as the distance
from the surface where the flow attains 99% of
the free stream velocity. The velocity profile
isn't linear but about 40% of the thickness from
the surface the flow will be at around 2/3rds the
free stream velocity n turbulent flow.
A reference I found said the boundary layer grows
about 16mm per meter from the leading edge
assuming all turbulent flow so aft of around half
way along the canopy the flow is turbulent and a
couple of meters aft of that will be about 32 mm thick. Any small
discontinuities there are buried deep in the
boundary layer and don't see anything like free
stream velocity. Drag depends on velocity squared so very little drag.
Now the FES is on the nose and there might be a
little laminar flow on the spinner in front of
the prop so the boundary layer is very thin there
when it encounters the folded prop which will
cause it to turbulate and the folded prop will
see most of the free stream velocity.
FES will certainly cause loss of significant
amounts of the laminar flow that is otherwise
present on the front of the fuselage.
Mike
At 10:53 PM 9/21/2016, you wrote:
Content-Type: multipart/alternative;
boundary="----=_NextPart_000_011B_01D2145A.FCB61810"
Content-Language: en-au
Youre worried about the increased drag from a FES?
Looking at that video, Id be more concerned
about the increased drag from that appalling
panel fit, never mind the huge gaps and the
numerous screw heads. Look at the rear, where
the pylon extends: that panel is sticking about 5mm above the fuse.
It looks like a dodgy home-built botch job.
Btw why not make the thing extend towards the
fuse? I cant recall if the motor was too wide,
and life is too short to wait for it to load again
From: Aus-soaring
[mailto:[email protected]] On Behalf Of Mike Borgelt
Sent: Tuesday, 20 September 2016 7:26 PM
To: Discussion of issues relating to Soaring in Australia.
Subject: Re: [Aus-soaring] electric self launch
At 07:04 PM 9/20/2016, you wrote:
Any  good links?
I found a schematic diagram which indicates that
the motor has a pusher folding prop. Not sure
how it retracts and fits in the fuselage with the blades sticking up?
Here you go:
<http://www.gpgliders.info/technik/>http://www.gpgliders.info/technik/
Scroll down to the videos. They took quite a
while to load here. The link seems slow.
Sheer bloody genius I think.
Mike
Borgelt Instruments - design & manufacture of
quality soaring instrumentation since 1978
<http://www.borgeltinstruments.com/>www.borgeltinstruments.com
tel: 07 4635 5784 overseas: int+61-7-4635 5784
mob: 042835 5784 : int+61-42835 5784
P O Box 4607, Toowoomba East, QLD 4350, Australia
_______________________________________________
Aus-soaring mailing list
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Borgelt Instruments - design & manufacture of
quality soaring instrumentation since 1978
www.borgeltinstruments.com
tel: 07 4635 5784 overseas: int+61-7-4635 5784
mob: 042835 5784 : int+61-42835 5784
P O Box 4607, Toowoomba East, QLD 4350, Australia
_______________________________________________
Aus-soaring mailing list
[email protected]
http://lists.base64.com.au/listinfo/aus-soaring
