Quantcast

Flying wing as cheap and simple option for basic fun flying.

HomeBuiltAirplanes.com

Help Support HomeBuiltAirplanes.com:

blane.c

Well-Known Member
HBA Supporter
Joined
Jun 27, 2015
Messages
4,398
Location
capital district NY
Although most of my time is with tractor engines on the wing they were well behind the cockpit and did not affect the view forward, considering the amount of crud they generated this is a good thing. I guess it is just looks that people like the engine on the front but considering mostly when you fly it is for the view do they really want the thing up in front? It is largely just a view obstruction.
 

erkki67

Well-Known Member
Joined
Feb 18, 2010
Messages
2,331
Location
Romont / Fribourg / Switzerland
Blane, I don’t agree regarding the prop position, having it up in front generates an additional airflow over the wing which generates lift. On the other hand a pusher pilot will fly his bird the same way, either engine on or off.
 

blane.c

Well-Known Member
HBA Supporter
Joined
Jun 27, 2015
Messages
4,398
Location
capital district NY
Blane, I don’t agree regarding the prop position, having it up in front generates an additional airflow over the wing which generates lift. On the other hand a pusher pilot will fly his bird the same way, either engine on or off.
Sorry because I like you but BS.
 

Riggerrob

Well-Known Member
Joined
Sep 9, 2014
Messages
1,716
Location
Canada
Sorry because I like you but BS.
As the American-built Dean Delta proved, delta pushers can exhibit complex pitch problems during take-off. For the purposes of this debate, wee will consider deltas to be merely short-span flying -wings.
First, the keep the propeller out of the mud, they need long main landing gear legs. ... at least half the diameter of the propeller.
Secondly, to prevent the airplane from tipping back on its tail - when parked with seats empty - those main wheels need to be a long way aft of the centre of gravity and centre of lift.
Thirdly, balance requires locating the propeller immediately aft of the trailing edge. Some deltas require extended drive shafts for balance. These extended drive shafts bring with them a whole series of vibration issues. This can create unstable airflow over inboard control surfaces when power is pulled to idle.
Fourthly, with the thrust line that far above the main wheels, it creates a pitch down moment with full power and a pitch up moment with zero power.
Since most take-off criteria require a large pitch-up moment - to lift the nose-wheel for take-off - but immediately after lift-off the pilot needs to relax pitch-up control inputs to avoid pitching up to ridiculously steep angles.
All those problems combined to wreck the Dean Delta during its first take-off.

That is why the majority of successful propeller-driven deltas: Delta Kitten, Dyke Delta, Facetmobile, Verhees Delta, etc. are tractors. The nose-mounted propeller is better for balance and its height can be fixed by a nosewheel that holds the wing at the precise angle needed for take-off. This pitch angle also happens to be the precise angle needed for landing. There is little point to flyng at a steeper angle of attack, because it just generates massive amount of induced drag which kills climb performance or increases sink rate. Rear landing gear legs can be short and light because they only need to prevent the trailing edge from dragging in the weeds.
 

blane.c

Well-Known Member
HBA Supporter
Joined
Jun 27, 2015
Messages
4,398
Location
capital district NY
 

Hot Wings

Grumpy Cynic
HBA Supporter
Log Member
Joined
Nov 14, 2009
Messages
7,451
Location
Rocky Mountains
Between my personal situation and all of this Covid craziness it will still be a while before the plans are on the market again for the AV-36.

Lots of misinformation on the Wiki page for the AV-45. Completely different plane than the AV-36 - other than the general look.
 

blane.c

Well-Known Member
HBA Supporter
Joined
Jun 27, 2015
Messages
4,398
Location
capital district NY
Between my personal situation and all of this Covid craziness it will still be a while before the plans are on the market again for the AV-36.

Lots of misinformation on the Wiki page for the AV-45. Completely different plane than the AV-36 - other than the general look.
Are you desiring to offer specialty parts in addition to the plans?
 

Hot Wings

Grumpy Cynic
HBA Supporter
Log Member
Joined
Nov 14, 2009
Messages
7,451
Location
Rocky Mountains
Are you desiring to offer specialty parts in addition to the plans?
That was part of the original plan but given the cost of wood and the shipping involved - both ways - there just isn't any practical way to do the wood parts for a reasonable price. Metal parts? Maybe in the future if there is enough interest.

Debrayer isn't interested in doing plans for the Pelican. I think there is more of a market for it than there is for the AV-36. In our modern world a composite version of that seems to make a lot more sense than the wood AV-36. The have a slightly different mission but there is enough overlap to make me happy with the smaller plane.
 

blane.c

Well-Known Member
HBA Supporter
Joined
Jun 27, 2015
Messages
4,398
Location
capital district NY
That was part of the original plan but given the cost of wood and the shipping involved - both ways - there just isn't any practical way to do the wood parts for a reasonable price. Metal parts? Maybe in the future if there is enough interest.

Debrayer isn't interested in doing plans for the Pelican. I think there is more of a market for it than there is for the AV-36. In our modern world a composite version of that seems to make a lot more sense than the wood AV-36. The have a slightly different mission but there is enough overlap to make me happy with the smaller plane.
You may consider the VP-3?
 

nestofdragons

Well-Known Member
Joined
Jun 8, 2016
Messages
389
Location
Near Antwerp, Belgium

nestofdragons

Well-Known Member
Joined
Jun 8, 2016
Messages
389
Location
Near Antwerp, Belgium
As the American-built Dean Delta proved, delta pushers can exhibit complex pitch problems during take-off. For the purposes of this debate, wee will consider deltas to be merely short-span flying -wings.
First, the keep the propeller out of the mud, they need long main landing gear legs. ... at least half the diameter of the propeller.
Secondly, to prevent the airplane from tipping back on its tail - when parked with seats empty - those main wheels need to be a long way aft of the centre of gravity and centre of lift.
Thirdly, balance requires locating the propeller immediately aft of the trailing edge. Some deltas require extended drive shafts for balance. These extended drive shafts bring with them a whole series of vibration issues. This can create unstable airflow over inboard control surfaces when power is pulled to idle.
Fourthly, with the thrust line that far above the main wheels, it creates a pitch down moment with full power and a pitch up moment with zero power.
Since most take-off criteria require a large pitch-up moment - to lift the nose-wheel for take-off - but immediately after lift-off the pilot needs to relax pitch-up control inputs to avoid pitching up to ridiculously steep angles.
All those problems combined to wreck the Dean Delta during its first take-off.

That is why the majority of successful propeller-driven deltas: Delta Kitten, Dyke Delta, Facetmobile, Verhees Delta, etc. are tractors. The nose-mounted propeller is better for balance and its height can be fixed by a nosewheel that holds the wing at the precise angle needed for take-off. This pitch angle also happens to be the precise angle needed for landing. There is little point to flyng at a steeper angle of attack, because it just generates massive amount of induced drag which kills climb performance or increases sink rate. Rear landing gear legs can be short and light because they only need to prevent the trailing edge from dragging in the weeds.
If you like more convicing about why place a tractor on a flying wing, go read this topic in this forum:
FLYING WINGS / Tractor VS pusher / Marko's vision
 

Latest posts

Top