Today's Message Index:
----------------------
1. 12:30 AM - Auxiliary- Longranger Fuel Tank ARM (tonyvaccarella)
2. 03:52 AM - Re: Auxiliary- Longranger Fuel Tank ARM (h&jeuropa)
3. 04:12 AM - Re: Auxiliary- Longranger Fuel Tank ARM (davidjoyce@doctors.org.uk)
4. 05:50 AM - Re: The Obsidian File - Mono Wheel Fairing (Area-51)
5. 06:17 AM - Re: Re: The Obsidian File - Mono Wheel Fairing (Pete)
6. 06:25 AM - Re: The Obsidian File - Mono Wheel Fairing (Area-51)
7. 09:15 AM - Re: Re: The Obsidian File - Mono Wheel Fairing (Bud Yerly)
8. 03:26 PM - Re: The Obsidian File - Mono Wheel Fairing (Area-51)
9. 06:39 PM - Re: The Obsidian File - Mono Wheel Fairing (Area-51)
10. 09:09 PM - Re: The Obsidian File - Mono Wheel Fairing (Area-51)
Message 1
| INDEX | Back to Main INDEX |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Auxiliary- Longranger Fuel Tank ARM |
Hi fine Europa people,
Soon Ill be having my W&B done for my Europa XS. The kit I purchased came with
the auxiliary Longranger fuel tank. Although Ive looked, I cant find an official
ARM from the datum for this tank. The aircraft fuel tank ARM is 76" while the
baggage area is listed as 88". For those of you who have this tank installed,
would you mind sharing the ARM utilised for W&B calculations?
Many thanks for your help.
Tony
--------
Tony Vaccarella
Mascot NSW 2020
Sydney Australia
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=510671#510671
Message 2
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Auxiliary- Longranger Fuel Tank ARM |
Tony,
We use 85 inches.
Jim & Heather
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=510672#510672
Message 3
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Auxiliary- Longranger Fuel Tank ARM |
Tony, I just split the difference, ending up with82" but you can easily
enough measure from the cowling joggle (the zero ref point) to the
centre of the tank. Regards, David Joyce, ex GXSDJ
On 2023-04-23 08:29, tonyvaccarella wrote:
> <tony@weimagine.com.au>
>
> Hi fine Europa people,
> Soon Ill be having my W&B done for my Europa XS. The kit I purchased
> came with the auxiliary Longranger fuel tank. Although Ive looked, I
> cant find an official ARM from the datum for this tank. The aircraft
> fuel tank ARM is 76" while the baggage area is listed as 88". For those
> of you who have this tank installed, would you mind sharing the ARM
> utilised for W&B calculations?
> Many thanks for your help.
> Tony
>
> --------
> Tony Vaccarella
> Mascot NSW 2020
> Sydney Australia
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=510671#510671
>
Message 4
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: The Obsidian File - Mono Wheel Fairing |
The past weekend has not been good for flying; so more numbers were crunched and
more fairings were assessed; it was interesting to try some known shapes, no
shapes, different retraction heights, and an initial design developed way back
near the beginning of all this.
As usual the control piece was the standard mono in standard flight configuration
at 100kt velocity (51m/sec). The airframe was stripped back to fuselage only
to reduce computer power and solving time. Several indicators were implemented,
Drag, Lift, Surface Velocity, Surface Acoustic Power... Fairings were tried
as semi and fully enclosed scenarios.
What the computer said...
The standard mono wheel, when retracted, skips on its tyre upon free stream air;
most all the remaining tyre remains within a protected pocket created by the
lower cowl deflector covering the muffler... employing a fairing does little
to reduce drag, however it does reduce acoustic noise within the undercarriage
well... a fully sealed fairing reduces this acoustic noise to near zero... the
variance upon drag factor between no fairing and fully enclosed is about 1kg
out of 38kg total; Lift variance is 1.8kg less with a fairing out of 7.8kg total
and is probably due to the tyre skipping on the free stream air... and thats
about it for the mono wheel faring with the ball ended enclosed shape providing
the best aerodynamic results.
Myth Busted...
Attached images relate to velocity and acoustic comparisons.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=510674#510674
Attachments:
http://forums.matronics.com//files/650ac4ad_8ace_4aa2_b79d_18796976a9cc_383.jpeg
http://forums.matronics.com//files/32e7836b_5949_4cbd_994b_39d722c8a709_207.jpeg
http://forums.matronics.com//files/aaa5982b_700b_4685_bd02_7070a8f2499a_758.jpeg
http://forums.matronics.com//files/51777a11_f283_4de4_977b_e4e25da175dc_170.jpeg
http://forums.matronics.com//files/1bda5df8_c3ac_4abe_9328_5eba78fd7649_689.jpeg
http://forums.matronics.com//files/5a94f80c_231a_48de_809f_756f92b4fb8d_119.jpeg
http://forums.matronics.com//files/1e525fe3_d8ab_46b6_80dd_80ab5445d0ca_191.jpeg
http://forums.matronics.com//files/469d3cbb_0ecb_4af7_9f9a_3b67e318f705_285.jpeg
Message 5
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: The Obsidian File - Mono Wheel Fairing |
Different from noise, i notice significant (and irritating to me lol) buffeting
starting at 120knots and increasing slightly as speed increases.
Intuitively, buffeting energy would be draggy with the pressure waves traveling
outward from the tunnel.
PeteZ
> On Apr 23, 2023, at 8:56 AM, Area-51 <goldsteinindustrial@gmail.com> wrote:
>
>
> The past weekend has not been good for flying; so more numbers were crunched
and more fairings were assessed; it was interesting to try some known shapes,
no shapes, different retraction heights, and an initial design developed way back
near the beginning of all this.
>
> As usual the control piece was the standard mono in standard flight configuration
at 100kt velocity (51m/sec). The airframe was stripped back to fuselage only
to reduce computer power and solving time. Several indicators were implemented,
Drag, Lift, Surface Velocity, Surface Acoustic Power... Fairings were tried
as semi and fully enclosed scenarios.
>
> What the computer said...
>
> The standard mono wheel, when retracted, skips on its tyre upon free stream air;
most all the remaining tyre remains within a protected pocket created by the
lower cowl deflector covering the muffler... employing a fairing does little
to reduce drag, however it does reduce acoustic noise within the undercarriage
well... a fully sealed fairing reduces this acoustic noise to near zero...
the variance upon drag factor between no fairing and fully enclosed is about 1kg
out of 38kg total; Lift variance is 1.8kg less with a fairing out of 7.8kg
total and is probably due to the tyre skipping on the free stream air... and thats
about it for the mono wheel faring with the ball ended enclosed shape providing
the best aerodynamic results.
>
> Myth Busted...
>
> Attached images relate to velocity and acoustic comparisons.
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=510674#510674
>
>
>
>
> Attachments:
>
> http://forums.matronics.com//files/650ac4ad_8ace_4aa2_b79d_18796976a9cc_383.jpeg
> http://forums.matronics.com//files/32e7836b_5949_4cbd_994b_39d722c8a709_207.jpeg
> http://forums.matronics.com//files/aaa5982b_700b_4685_bd02_7070a8f2499a_758.jpeg
> http://forums.matronics.com//files/51777a11_f283_4de4_977b_e4e25da175dc_170.jpeg
> http://forums.matronics.com//files/1bda5df8_c3ac_4abe_9328_5eba78fd7649_689.jpeg
> http://forums.matronics.com//files/5a94f80c_231a_48de_809f_756f92b4fb8d_119.jpeg
> http://forums.matronics.com//files/1e525fe3_d8ab_46b6_80dd_80ab5445d0ca_191.jpeg
> http://forums.matronics.com//files/469d3cbb_0ecb_4af7_9f9a_3b67e318f705_285.jpeg
>
>
>
>
>
>
Message 6
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: The Obsidian File - Mono Wheel Fairing |
Interesting... probably worth increasing the velocity parameters to 75m/sec and
see what happens
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=510676#510676
Message 7
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: The Obsidian File - Mono Wheel Fairing |
Consider also the gap between the frame/wheel and fuselage opening. That g
ap has to be cut "like Goldilocks" or just right or air swirls around and g
ushes up into the well.
NACA had tests on the partially retracted gear and frankly, a half-buried t
ire is a good compromise. Drag was decreased slightly in the wind tunnel w
ith a narrower gap. In these tests the gap was closed up to the tire and t
he tire gap was as small as practical. Photos are grainy and virtually imp
ossible to find from NASA. Heinkel did work in this area also.
Most 1930-40s aircraft with partially exposed wheels did hide the wheels in
the nacelles or made covers for the gap in the wings back to the tire to c
lean up the gap and reduce drag. Making a flange with rounded edge in the
rear of the wheel well area was also done to clean up the exit and prevent
air pressure buildup in the well. ( As done by Seversky in the P-35) Dougl
ass put the oil cooler on the C-47 just before the tire to cut the drag. C
rude but effective. Bellanca did no streamlining until the Viking series.
Adding a small cover to the front helped, so they made a complete door to
enclose the gear. A full fairing is nice, but the extra weight and complex
ity becomes tedious to complete effectively. Many folks up north simply re
moved the rear door.
See NACA Report 518 for some drag numbers (very crude stuff, drag is in pou
nds, but the tire size is familiar looking) to bounce off your calcs.
Enjoy your computer work. I=92m doing 3D printing stuff and cooling airflo
w and enclosure mods using similar programs. The learning curve was and st
ill is steep. Too many assumptions have to be made to compromise on airflo
w and pressure build up. Yuck. It is a hit and miss (for me anyway) on ge
tting the best airflow bang for the buck and time.
Best Regards,
Bud Yerly
________________________________
From: owner-europa-list-server@matronics.com<mailto:owner-europa-list-serve
r@matronics.com> <owner-europa-list-server@matronics.com<mailto:owner-europ
a-list-server@matronics.com>> on behalf of Area-51 <goldsteinindustrial@gma
il.com<mailto:goldsteinindustrial@gmail.com>>
Sent: Sunday, April 23, 2023 9:25:27 AM
t@matronics.com<mailto:europa-list@matronics.com>>
Subject: Europa-List: Re: The Obsidian File - Mono Wheel Fairing
<mailto:goldsteinindustrial@gmail.com>>
Interesting... probably worth increasing the velocity parameters to 75m/sec
and see what happens =F0=9F=A4=B7=F0=9F=8F=BC=8D=99=82=EF=B8=8F
Read this topic online here:
https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fforums.ma
tronics.com%2Fviewtopic.php%3Fp%3D510676%23510676&data=05%7C01%7C%7Cf5c68
b91124f4faf585008db43fe9378%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C63
8178532913400064%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMz
IiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=ZNYEwvj7bHDZSoIxiv
vTzC1W7Mx4%2F1DOYSUmIjNApX4%3D&reserved=0<http://forums.matronics.com/vie
wtopic.php?p=510676#510676>
%2Fwww.matronics.com%2FNavigator%3FEuropa-List&data=05%7C01%7C%7Cf5c68b91
124f4faf585008db43fe9378%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C63817
8532913400064%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiL
CJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=2BFLi7Iy0Wy8ZHu3Xy6jY
pp8I6cv1HFh2qn3gZk%2BITk%3D&reserved=0<http://www.matronics.com/Navigator
?Europa-List>
%2Fforums.matronics.com%2F&data=05%7C01%7C%7Cf5c68b91124f4faf585008db43fe
9378%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C638178532913400064%7CUnkn
own%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXV
CI6Mn0%3D%7C3000%7C%7C%7C&sdata=zO5HWCl3PT%2FEJ40aSfBkZTW2JidmV0a%2B4DaO%
2BDIUlqc%3D&reserved=0<http://forums.matronics.com/>
%2Fwiki.matronics.com%2F&data=05%7C01%7C%7Cf5c68b91124f4faf585008db43fe93
78%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C638178532913400064%7CUnknow
n%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI
6Mn0%3D%7C3000%7C%7C%7C&sdata=5eva5Xt5x7gUfjSbqWa1ivlwxjP2XjLNNgC2NVGIXEc
%3D&reserved=0<http://wiki.matronics.com/>
F%2Fmatronics.com%2Fcontribution&data=05%7C01%7C%7Cf5c68b91124f4faf585008
db43fe9378%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C638178532913400064%
7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWw
iLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=SYpWITnvwFIIRe8XIhntUn9%2BIr4lanSrV
aRWn9Xtj4E%3D&reserved=0<https://matronics.com/contribution>
Message 8
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: The Obsidian File - Mono Wheel Fairing |
Thanks for the input there Bud; always thought provoking..
Gaps and edges can be noise generators. The semi enclosed fairing has a large gap
at the rear to allow tyre passing. On something like the europa installing
bristle brushes at the gaps might offer an affective cheap and light solution
here.
Cooling ducts on 3D printers are a real challenge. I did one a few years back as
i wasnt happy with the factory side flow versions; so i designed up a really
affective single head unit which resulted in a 150g lighter print head; took
five assumptions to get the flow balance correct... works great! Let me know if
you are interested, can send you the STL file, ready to print.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=510681#510681
Message 9
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: The Obsidian File - Mono Wheel Fairing |
Breakfast today has turned into brunch as all three model variations had a higher
velocity of 75m/sec (150kt) applied; and revealed an interesting anomaly.
Its not certain or being ruled out that at the higher air speed an acoustic pressure
wave is detected traveling rearward along the fuselage belly aft of the
main gear. (the fully enclosed fairing does not exhibit this trait).
Other results on the acoustic aspect shows db levels increasing some 50%; the loudest
areas being where deflected free stream air at the lower engine cowl fairing
rejoins slower moving air exiting the engine bay area; some 105db; quite
audible over everything... installing a trailing fence may reduce this turbulent
corridor.
The pressure wave though is interesting, at 70-80db it would be noticeable and
the cause of it would likely be related to the flutter of turbulence created by
air passing over and behind the cylindrical shape of the tyre. As Bud mentions
above there is also the added element of air escaping the gaps of the fairing
and exposed main gear rejoining faster moving air... The belly of the fuselage
is quite flexible and is likely oscillating enough to cause annoying pressure
pulses within the cockpit.
Employing fairing fences might provide an answer to the above situation.
Regarding Drag and Lift comparatives at 150kt, standard and semi enclosed setups
were identical in Drag with the later giving up 3.0kg of Lift; again the tyre
is removed from the free stream... The fully enclosed setup provides some 3.0kg
Drag reduction and gives up 2.0kg of Lift.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=510682#510682
Attachments:
http://forums.matronics.com//files/8a81f6a8_a74d_495e_875f_c907cb0e1ce9_212.jpeg
http://forums.matronics.com//files/c5e5c0da_b8c0_47f6_8ad8_506a68b62282_464.jpeg
http://forums.matronics.com//files/9b70a766_46dc_4944_9fc2_4dcc7aa93d98_213.jpeg
Message 10
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: The Obsidian File - Mono Wheel Fairing |
Brunch has turned into lunch..
The fence concept has provided value by reducing the acoustic pressure pulses to
almost zero and assisting in keeping trailing turbulence tighter within the
fuselage centerline... Drag and Lift gains and losses were not anything worth
noting; mostly "shut that noise up"; advantages being greatest using the semi
enclosed fairing option, however both semi enclosed and standard setups nullified
the trailing pressure pulse effects... two thumbs up on this one.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=510684#510684
Other Matronics Email List Services
These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.
-- Please support this service by making your Contribution today! --
|