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bwainfan

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Feb 10, 2007
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Still wishing Barnaby would do a 4 (or 6) seat version, or at least the PAV 2 seater he postulated. I got to see the original when he flew it to OSH, and have always been very interested in the concept, but cannot justify building a single seat a/c. I could be completely wrong, but it 'feels' like the concept should scale up in capacity with even more improvement in structural efficiency.

Charlie
Still working on the design of the 2-seater. Hope to start building before too long.
 

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Hephaestus

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Jun 25, 2014
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YMM
Still working on the design of the 2-seater. Hope to start building before too long
Development of the PAV project?

I know I'm wierd but - I really like that proposed composite flat panel construction. Still has to be my favorite proposal.

That and cruising around in a carbon fiber wobbling goblin would be sweet :wonder::beer:
 

rotax618

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Evans Head Australia
Please don’t take this as criticism of your design but from my experiments with faceted deltas you will loose a lot of lift by not having a flat windscreen, it is part of the wing in a lifting body aircraft, the other problem I can see is the thickest part of the outer wing is too far back. Forget the tip fins on my models, they only interfered with the vortex at low speed, the model with09903003-8283-41C5-A254-5C55CB4A12EA.jpeg7B5971DA-2662-4286-B4DC-D43343322059.jpeg0795ACBF-C951-4DAD-9B51-E2D1F06D9DFD.jpeg the twin yellow fins had a sharp windscreen and its performance was inferior to the model in front with the single fin and flat windscreen. As Barnaby found with airflow studies a flat windscreen needs a slight curve at the top to assist the airflow.F8F2F76E-AAFB-4AF8-B423-75B6F7D5D5AD.jpeg
 

Mavigogun

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Progressive Texas
Please don’t take this as criticism of your design but from my experiments with faceted deltas you will loose a lot of lift by not having a flat windscreen, it is part of the wing in a lifting body aircraft, the other problem I can see is the thickest part of the outer wing is too far back. *snip* As Barnaby found with airflow studies a flat windscreen needs a slight curve at the top to assist the airflow.
To be clear: the model pictured in my post above is reposted from Barnaby‘s post, #41. It is not my work. I believe the rudder placement- and thickness of the cord aligned to them -maybe detachable wing considerations. The lighting may be playing with perception; viewing the earlier image of what may be the same model on the first page of this thread, the lateral angles of the central canopy panes seem relatively shallow.

I recall Barnaby remarking on critical maximum facet angles demonstrated by paint-or-some-such dribbled on wind tunnel models. I don’t recall rounding of the FMX-4 or 5 canopy tops, nor do they overtly appear so in my photo references. Might you point me to where this was talked about? I wonder if “slight” was quantified.
 
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rotax618

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I was referring to the paint on the wind tunnel models, In hindsight, perhaps my windscreen was more steeply raked. My comments about the loss of lift was inspired by the centre section of the Dyke Delta, which contributes a considerable component of the overall lift.
 

steveair2

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Jun 1, 2007
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Dallas Texas
Glad to see you making progress Mr. Wainfan. I really enjoyed your forum at Oshkosh a few years back.
I built a Thing 3 you designed a few years ago. I converted it to electric power and added landing gear, canopy and elevons.
Too scared to fly it at the moment. Keep up the great work.

Thing 3.png
 
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Urquiola

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Aug 23, 2013
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Madrid, Spain
Ref. Urquoila's comments:

All very possible, unfortunately, no one sells an extremely lightweight generator in the power range required. One could build one from brushless motors and an IC engine, but that's another major development project. Those working away in their hangars or garages have to keep the number of development projects to a minimum in order to ever get something finished.

One advantage of double rudders is to be able to use them as speed brakes. It also reduces the size and structure to have double rudders rather than a single one. Many models have been built with singles and they fly just fine. It's really a matter of choice.
Some turbine generators, APU and so on appear every now and then in eBay.com Just need keep on searching. I don't like anything that can become highly asimmetrical in case of failure. Blessings +
 

Urquiola

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Some turbine generators, APU and so on appear every now and then in eBay.com Just need keep on searching. I don't like anything that can become highly asimmetrical in case of failure. Blessings +
Aeroexpo.online offers some suitable engines, among it a Wankel Engine-Generator unit, engine has oil cooled rotor, liquid cooled housing, reported as arrangement with best efficiency for an RCE. AirKmotors.com offers cheap air cooled engines. btw: water is among the worse fluids in taking heat away. Blessings +
 

Vigilant1

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btw: water is among the worse fluids in taking heat away. Blessings +
?? The isobaric mass heat capacity and the isobaric volumetric heat capacity of water is very good compared to most commonly available fluids (liquid or gas). It may have other problematic attributes as a coolant, but a specific quantity of water (mass or volume) can move a LOT of heat for each degree of temperature rise compared to oil, glycol, etc.
 
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Urquiola

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Aug 23, 2013
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Madrid, Spain
Glad to see you making progress Mr. Wainfan. I really enjoyed your forum at Oshkosh a few years back.
I built a Thing 3 you designed a few years ago. I converted it to electric power and added landing gear, canopy and elevons.
Too scared to fly it at the moment. Keep up the great work.

View attachment 95662
I added this link before, but the NASA Langley Wind Tunnel data about center of gravity in the Lifting bodies could perhaps be applied to other machines.
Blessings +
 

Urquiola

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Aug 23, 2013
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Madrid, Spain
Development of the PAV project?

I know I'm wierd but - I really like that proposed composite flat panel construction. Still has to be my favorite proposal.

That and cruising around in a carbon fiber wobbling goblin would be sweet :wonder::beer:
I had a dream: having the PAV panels made of Pladur, a building material available in Spain, analogs exist everywhere, two plates of plaster and in between a honeycomb layer, skin can be made of many materials. When looking for elements for my AMC Pacer, I found that what is called 'Reflectix' has an equivalent in isolation sheets for AC in buildings, but at 10% of cost. Blessings +
 

Urquiola

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Aug 23, 2013
Messages
252
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Madrid, Spain
?? The isobaric mass heat capacity and the isobaric volumetric heat capacity of water is very good compared to most commonly available fluids (liquid or gas). It may have other problematic attributes as a coolant, but a specific quantity of water (mass or volume) can move a LOT of heat for each degree of temperature rise compared to oil, glycol, etc.
The 'BOSCH Manual of Automobile Technique' indicates, for Water, a Thermal Conductivity of 0.6 W/(m.K); Specific Thermal Capacity 4.18 kJ/(kg.K); for Lubricanting Oil: 0.13 W/(m.K); 2.09 kJ/(kg.K); for Water/ Antifreeze mix, 54% vol, values are: 0.40 W/(m.K), 3.43 kJ/(kg.K); Oil freezing temperature is -20º C, but it does not increase in volume when freezing, this feature of water, ice has a larger volumen than liquid water, is what breaks engine blocks under extreme cold. Deutz in Germany produces some industrial engines with oil cooling, the Twin-Flat engines in Series A Citroën cars (2CV, Ami, Dyane, Mehari) have some parts oil cooled, with a pump and a radiator; taking away heat with oil could be just a matter of liquid circulation speed, pump, radiator size. Why not testing? Blessings +
 

Vigilant1

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Urquiila,
What you wrote was:
btw: water is among the worse fluids in taking heat away. Blessings +
In fact, water is an excellent 'fluid for taking heat away', and the specs you quote from Bosch support the superiority of water over oil for removing heat.
Now, in our own particular use (IC engine cooling ), water has some important challenges: e.g. an inconvenient boiling point, an inconvenient freezing point, supporting corrosion of many metals. Still, from an operational perspective it is still so much better at "taking heat away'" compared to other options (esp oil) that engine designers still use water based coolants with added substances (glycol for freeze/boil temp improvement, corrosion inhibiters, etc) to remove bulk heat. Water is cheap, not flammable, has low viscosity (so lower film thickness on the metal surface=better heat transfer).

Use of oil as a heat transfer fluid is preferred to water in some applications despite its poorer ability to "take heat away.'" If the surface to be cooled can't be brought down to a temp amenable to water based coolants, if oil needs to be present at the surface anyway for lubrication, if the designers don't want the weight, complexity, or cost of a second pump, circuit, and radiator, etc, then they will try to make oil cooling work, and it often works well enough.
Water is among the best fluids "in taking heat away."
 
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vhhjr

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Joined
Jun 29, 2003
Messages
189
With regard to Facetmobile panels: We looked at several alternatives to tubes and fabric and they all came out heavier. Even very pricey Nomex honeycomb with carbon fiber facings when thick enough to avoid "Oil Canning" were heavy compared to fabric. If the speed is raised above the light sport range composite panel begin to be attractive due to the ballooning of large fabric panels.

There is a big advantage to composite panels when a production aircraft is considered. The hand labor goes way down when proper tooling is used to make skin panels and bulkheads.

The FMX-4 Facetmobile has over 400 ft2 of surface area so it's easy to figure out the weight of any alternative covering method. With an gross weight of less than 750 lbs you don't get much left for skin weight.

Vince Homer
 

Riggerrob

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Sep 9, 2014
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Location
Canada
Please don’t take this as criticism of your design but from my experiments with faceted deltas you will loose a lot of lift by not having a flat windscreen, it is part of the wing in a lifting body aircraft, the other problem I can see is the thickest part of the outer wing is too far back. Forget the tip fins on my models, they only interfered with the vortex at low speed, the model withView attachment 95625View attachment 95626View attachment 95627 the twin yellow fins had a sharp windscreen and its performance was inferior to the model in front with the single fin and flat windscreen. As Barnaby found with airflow studies a flat windscreen needs a slight curve at the top to assist the airflow.View attachment 95628
What is the minimum radius to smooth airflow over the windshield?
How does it compare with the outside diameter of structural tubes?
Can you "cheat" radius by wrapping a light-weight sleeve around a structural tube?
 
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