Latest photos before the airshow.
Lot more work but at least it looks like an aircraft.....!
Flying Legend Tucano-R at Rylstone Tucano build now MeWe - Gary Spencer Salt
Showing posts with label Insights. Show all posts
Showing posts with label Insights. Show all posts
Monday, 21 May 2018
Wednesday, 16 May 2018
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Lots of new information about the aircraft in preparation for the Rylstone Air-Park Flyin
Monday, 30 October 2017
Web Site
Flying Legend Au now has a new web site
http://www.flyinglegend.com.au/Thanks for visiting
Sunday, 23 July 2017
Tucano Flight Review
This blog covers my impressions flying the Tucano in Sicily.
Overview
My return to flying was outlined in the first blog, but some background might help the reader. When flying in GA most of my training was undertaken in the Cherokee Warrior, and Archer followed with time in the Cessna 150 AeroBat, Grumman Tiger and Decathlon accruing total hours of about 130 when I stopped.
On my return, I started in the Jabiru and currently flying a Foxbat with about 30 hours since starting the project. The building was not my first choice but the Tucano did grab my attention.
Note: So why do the Europeans use kph? - no one could give an answer other than it makes them feel like they are going faster
Flying a Tucano R Turbo
One reason to visit Flying Legend factory in Caltagirone was to test fly the current factory demonstrator aircraft and to be checked out in the Tucano R.
The first impression as you approach the aircraft for the first time is its size, this is a large aircraft physically for an ultralight and could best be described as a retractable RV8 with a Rotax 912.
Entry to the cockpit is made easier using the fuselage step, and once in the back seat, it proved to be roomy for this real size pilot. Fully ensconced, Chico aka "The Commander" Flying Legends ex-airforce pilot took me through the operation of the instruments and systems fitted to the rear seat of this Tucano.
With both of us buckled in and a final briefing it was time to go flying.
It was summer day of 40 degrees C with an MTOW of about 690 kg, this aircraft was fitted with a Rotax 914 that was to be removed and replaced with a supercharged engine package and that will be the test bed for Flyings Legends 912 upgrade kits.
With the necessary pre-flight checks completed, we lined up for departure at the factory's airfield, 115% power applied, acceleration was brisk and the aircraft lifted off at about 90 kph to establish climb at a safe 140 kph, retract gear, engine 100%, prop 5500 rpm, flap up and climb to 2400 ft with the VSI showing 650 fpm finally power to 30'' and 5000 rpm at 2400 ft.
Time to tackle the "Carrier", the company nickname for its airfield located in the base of a tight valley with hills on both sides. It was a real change from Rylstone with its clear flat paddocks all around the strips. After a couple of circuits, Chico requested a full stop, once back on the tarmac and shutdown Chico requested we now swap seats - I was now in the front.
Back in the air again and my initial impression is of sable platform riding through the air, not on it as the ultralights that currently I currently fly, aerlions felt firm but not heavy, elevators lighter with the rudder heavier.
A typical circuit consisted of reducing speed to 140 kph, gear down, prop fine, flap to 15 degrees and let the speed bleed back to 130 kph with 120 kph the minimum while manoeuvring to the field. Fly over the ridge, sweep down into the valley to sight the runway, reduce speed to 110 kph on short final, three green/full fine and sweep over the cane field at the threshold that hides a power line. All good, bleed back to 90 kph, flare and hold the nose while flying parallel to the runway and the Tucano will settle down smoothly, full stop and taxi again for a brief and prepare for another flight later.
Next flight, Chico requested we establish level flight 2400 feet for a few basic stalls - power off for a clean stall with no drama, again with full flap. The impression was that in both cases was that the nose was very high with only blue sky visible in the front of the bubble canopy with a clean but positive break requiring only a release of back pressure to resume normal flight with little or no rudder needed.
Steep turns of 50 degrees were just a matter of just inputting the required bank and adding power to maintain the nose attitude in a turn. Chico performed some basic aerobatics which was pure joy, again in the wing-over and roll, the aircraft maintained that on-rails feel.
Back to the field for more touch and go's and finally to a welcome full stop and like all things Italian, terminated with an Expresso.
Next day Chico and I left the factory field and flew for 15 minutes up the coast to a local airfield that was flat and at sea level. We flew up the coast between 1000 / 500 feet with the aircraft holding altitude smoothly with little pilot input.
Here a final set of accelerated stalls were undertaken by slowing the aircraft to within 20 kph of the stall and applying a sharp pull on the stick establishing an exaggerated pitch attitude with gear and flap down.
No change but the aircraft does now require more use of the rudder to keep the wings level with the largest difference being at full flap where the Tucano was noticeably more unstable going into the stall, requiring a more positive approach on the rudder to keep the wings level. All stalls produced a high nose attitude with a complete loss of the horizon at the point of stall, and there is no way I could mistake this for safe flight.
No apparent buffeting or stick feedback noted by myself, but the aircraft was clearly stalling by its nose attitude and sluggish response of the controls. At no time did the pilot detect a desire for the Tucano to drop a wing and long as the ball was centred and to recover, release back pressure.
Finally, an engine out landing was started from 2500 ft requiring a 180-degree turn to regain a visual on the runway keys, establish a glide, while through the whole approach the Tucano was predictable in descent allowing the pilot to finish with a curved path to pick up the runway centerline. With the nose on the keys, the landing gear/flaps extended for a textbook landing and more Espresso.
Later we returned for a full stop at the Carrier and more Espresso.
The rest was just a low time pilot trying hard and getting a lot of small thing wrong with the biggest issue the Tucanos ability to bleed and gain speed easily unlike the more basic aircraft that I currently fly.
,
My best memory is just flying behind that long nose terminating at the big spinner in a clear plastic bubble with the Mediterranean all around you, beautiful surroundings in an aircraft that just oozes pure military feel.
Stable and smooth are the two words that could describe the Tucano in all flight modes with landings that feel like you are in a much larger aircraft producing no noticeable float.
Comment
Can a low time pilot with only access to a Foxbat fly a Tucano? - Yes with more training, a careful approach and begin aware of their personal limits.
Overview
My return to flying was outlined in the first blog, but some background might help the reader. When flying in GA most of my training was undertaken in the Cherokee Warrior, and Archer followed with time in the Cessna 150 AeroBat, Grumman Tiger and Decathlon accruing total hours of about 130 when I stopped.
On my return, I started in the Jabiru and currently flying a Foxbat with about 30 hours since starting the project. The building was not my first choice but the Tucano did grab my attention.
Note: So why do the Europeans use kph? - no one could give an answer other than it makes them feel like they are going faster
Flying a Tucano R Turbo
One reason to visit Flying Legend factory in Caltagirone was to test fly the current factory demonstrator aircraft and to be checked out in the Tucano R.
The first impression as you approach the aircraft for the first time is its size, this is a large aircraft physically for an ultralight and could best be described as a retractable RV8 with a Rotax 912.
Entry to the cockpit is made easier using the fuselage step, and once in the back seat, it proved to be roomy for this real size pilot. Fully ensconced, Chico aka "The Commander" Flying Legends ex-airforce pilot took me through the operation of the instruments and systems fitted to the rear seat of this Tucano.
 |
| Aircraft Panel Impressed by the FlyBox EFIS |
With both of us buckled in and a final briefing it was time to go flying.
It was summer day of 40 degrees C with an MTOW of about 690 kg, this aircraft was fitted with a Rotax 914 that was to be removed and replaced with a supercharged engine package and that will be the test bed for Flyings Legends 912 upgrade kits.
With the necessary pre-flight checks completed, we lined up for departure at the factory's airfield, 115% power applied, acceleration was brisk and the aircraft lifted off at about 90 kph to establish climb at a safe 140 kph, retract gear, engine 100%, prop 5500 rpm, flap up and climb to 2400 ft with the VSI showing 650 fpm finally power to 30'' and 5000 rpm at 2400 ft.
Time to tackle the "Carrier", the company nickname for its airfield located in the base of a tight valley with hills on both sides. It was a real change from Rylstone with its clear flat paddocks all around the strips. After a couple of circuits, Chico requested a full stop, once back on the tarmac and shutdown Chico requested we now swap seats - I was now in the front.
Back in the air again and my initial impression is of sable platform riding through the air, not on it as the ultralights that currently I currently fly, aerlions felt firm but not heavy, elevators lighter with the rudder heavier.
A typical circuit consisted of reducing speed to 140 kph, gear down, prop fine, flap to 15 degrees and let the speed bleed back to 130 kph with 120 kph the minimum while manoeuvring to the field. Fly over the ridge, sweep down into the valley to sight the runway, reduce speed to 110 kph on short final, three green/full fine and sweep over the cane field at the threshold that hides a power line. All good, bleed back to 90 kph, flare and hold the nose while flying parallel to the runway and the Tucano will settle down smoothly, full stop and taxi again for a brief and prepare for another flight later.
Next flight, Chico requested we establish level flight 2400 feet for a few basic stalls - power off for a clean stall with no drama, again with full flap. The impression was that in both cases was that the nose was very high with only blue sky visible in the front of the bubble canopy with a clean but positive break requiring only a release of back pressure to resume normal flight with little or no rudder needed.
Steep turns of 50 degrees were just a matter of just inputting the required bank and adding power to maintain the nose attitude in a turn. Chico performed some basic aerobatics which was pure joy, again in the wing-over and roll, the aircraft maintained that on-rails feel.
Back to the field for more touch and go's and finally to a welcome full stop and like all things Italian, terminated with an Expresso.
Next day Chico and I left the factory field and flew for 15 minutes up the coast to a local airfield that was flat and at sea level. We flew up the coast between 1000 / 500 feet with the aircraft holding altitude smoothly with little pilot input.
Here a final set of accelerated stalls were undertaken by slowing the aircraft to within 20 kph of the stall and applying a sharp pull on the stick establishing an exaggerated pitch attitude with gear and flap down.
No change but the aircraft does now require more use of the rudder to keep the wings level with the largest difference being at full flap where the Tucano was noticeably more unstable going into the stall, requiring a more positive approach on the rudder to keep the wings level. All stalls produced a high nose attitude with a complete loss of the horizon at the point of stall, and there is no way I could mistake this for safe flight.
No apparent buffeting or stick feedback noted by myself, but the aircraft was clearly stalling by its nose attitude and sluggish response of the controls. At no time did the pilot detect a desire for the Tucano to drop a wing and long as the ball was centred and to recover, release back pressure.
Finally, an engine out landing was started from 2500 ft requiring a 180-degree turn to regain a visual on the runway keys, establish a glide, while through the whole approach the Tucano was predictable in descent allowing the pilot to finish with a curved path to pick up the runway centerline. With the nose on the keys, the landing gear/flaps extended for a textbook landing and more Espresso.
Later we returned for a full stop at the Carrier and more Espresso.
The rest was just a low time pilot trying hard and getting a lot of small thing wrong with the biggest issue the Tucanos ability to bleed and gain speed easily unlike the more basic aircraft that I currently fly.
,
My best memory is just flying behind that long nose terminating at the big spinner in a clear plastic bubble with the Mediterranean all around you, beautiful surroundings in an aircraft that just oozes pure military feel.
Stable and smooth are the two words that could describe the Tucano in all flight modes with landings that feel like you are in a much larger aircraft producing no noticeable float.
Comment
Can a low time pilot with only access to a Foxbat fly a Tucano? - Yes with more training, a careful approach and begin aware of their personal limits.
 |
| Maria my wife and Chico - first flight in 30 years |
It ended with what is called at the factory as the
Tucano smile for everyone
Tucano smile for everyone
Wednesday, 28 December 2016
Engine Cooling Ideas
This blog covers the background behind air cooling design
Overview
With the aircraft advancing and beign at home for a few weeks over Christmas it was decided to firm up the cooling of the cowl.
Why?
Simple, I would like to close up the hole under the nose gear but this is currently the primary means of cooling and engine air other components will be required.
The radiator is the primary concern as it size is fixed and options are few. Let get this straight it has worked in the factory aircraft for 300 plus hours and there are others on the way but one effect of closing a cowl is the internal temperatures climb and air has to have a routed in/out.
The first blog simply says you need ducts so that easy just build an internal cowl. The original design showed a connection to the fake exhaust - nice but not practical as to look correct they have to reside on the fuselage and the connection would be a bear.
What was needed was a means of extracting the air while maintaining the cowls look and this restricted the ideas to one - louvers. After a lot of work I have settled on a set of automotive louvers 5'' x 6.5 '' overall for a WRX.
The inlet in light orange will be installed as the airflow is underrated in climb remembering that engine and oil cooling have to be handled by the radiator and the calcs show the radiator and water flow underrated this mode. The heat exchanger for the oil will be incorporated into the engine shroud for a number of reasons but one is to allow the exchanger to have an air blast to help offset load on the radiator.
The front duct will decelerate the incoming air raising the dynamic pressure with the duct on the reverse side accelerating the air reversing the process and then raising the pressure at the exit again.
The other reason is that this mimics the pressure under the bonnet allowing air to exit into the moving stream under the cowl. The vents shown have a adjustable lips that extends up into the air flow effectively tripping the air stream creating a low pressure zone allowing the air in the duct to efficiently enter the moving stream of air. One [1] vent will be installed on the starboard side matching the SCATT hose.
Another vent will be placed on the port side to vent 12 kw of heat created by the cylinders and radiant heat from the exhausts, radiator and other items.
Note: This will only be effective with a sealed cowl
The fins are cooled by a downdraft pendulum used on the RV12, this will be covered in a later blog but in the heat exchanger plates located on its underside will be installed into the shroud inlet using incoming air to cool the cylinders taking some load off the radiator as the 64 mm diameter inlet has an excess of air available.
If door are installed they will have two sets of louvers fitted to allow the radiated heat to be ejected on the underbelly [see note above]
The final item examined was the supercharger air supply as this is also part of this equation. A 75 mm od supply was used for a simple reason, its what is available for the aftermarket automotive market. The inlet and filter are both carbon fibre and very light, cost effective with all connection being achieved using 75 / 64 mm od SCATT hose.
Comment
The initials calcs were based on a article for the Europa by Jans
Apologize for any error in advance
Overview
With the aircraft advancing and beign at home for a few weeks over Christmas it was decided to firm up the cooling of the cowl.
Why?
Simple, I would like to close up the hole under the nose gear but this is currently the primary means of cooling and engine air other components will be required.
The radiator is the primary concern as it size is fixed and options are few. Let get this straight it has worked in the factory aircraft for 300 plus hours and there are others on the way but one effect of closing a cowl is the internal temperatures climb and air has to have a routed in/out.
The first blog simply says you need ducts so that easy just build an internal cowl. The original design showed a connection to the fake exhaust - nice but not practical as to look correct they have to reside on the fuselage and the connection would be a bear.
What was needed was a means of extracting the air while maintaining the cowls look and this restricted the ideas to one - louvers. After a lot of work I have settled on a set of automotive louvers 5'' x 6.5 '' overall for a WRX.
 |
| Proposed duct - 550 mm overall |
The inlet in light orange will be installed as the airflow is underrated in climb remembering that engine and oil cooling have to be handled by the radiator and the calcs show the radiator and water flow underrated this mode. The heat exchanger for the oil will be incorporated into the engine shroud for a number of reasons but one is to allow the exchanger to have an air blast to help offset load on the radiator.
The front duct will decelerate the incoming air raising the dynamic pressure with the duct on the reverse side accelerating the air reversing the process and then raising the pressure at the exit again.
A wicker is just an additional trip at the front vent
The airflow behind the vent would be interesting
The airflow behind the vent would be interesting
 |
| RV12 Radiator / oil cooler duct |
Another vent will be placed on the port side to vent 12 kw of heat created by the cylinders and radiant heat from the exhausts, radiator and other items.
Note: This will only be effective with a sealed cowl
The fins are cooled by a downdraft pendulum used on the RV12, this will be covered in a later blog but in the heat exchanger plates located on its underside will be installed into the shroud inlet using incoming air to cool the cylinders taking some load off the radiator as the 64 mm diameter inlet has an excess of air available.
If door are installed they will have two sets of louvers fitted to allow the radiated heat to be ejected on the underbelly [see note above]
The final item examined was the supercharger air supply as this is also part of this equation. A 75 mm od supply was used for a simple reason, its what is available for the aftermarket automotive market. The inlet and filter are both carbon fibre and very light, cost effective with all connection being achieved using 75 / 64 mm od SCATT hose.
Comment
The rough estimate of the workload outlined below shows that there is a potential load at full power of 48 kw on the radiator with the water pump providing 50 Kw of water with 65 Kw of air available in level flight. If correct it means the system has to be very efficient in climb and when full power is beign used as every cubic cm of air must be harnessed along with the cooling water and there is a need to verify the capacity of the radiator in the real world carefully!.
Wishing I had paid a lot more attention when in sitting in the classes - always wise after the event so below is some rusty thermodynamics.
The initials calcs were based on a article for the Europa by Jans
Apologize for any error in advance
Maximum
power output Rotax Supercharged - 100 kW
Consumption
at maximum power 40 l/h, i.e. 11.1 ml/s.
Gasoline
represents 35 kJ of energy per ml.
Power
consumption is therefore 11.1 x 35 = 388 kW
Efficiency
is 100 / 388 = 26%.
Maximum
cruise power output = 79 kW
Consumption
at maximum cruise power is 29 l/h, i.e. 8.0 ml/s.
Power
consumption is 280 kW
Efficiency
is 28%.
75%
cruise power output 55.1 kW
Consumption
at 75% cruise power is 20.4 l/h, i.e. 5.67 ml/s.
Power
consumption is 198 kW
Efficiency
is 27.8%.
Total
heat production to be removed estimated :
388
– (85 * 1.13) – (12.5 * 1.13) = 278 kW.
Assumptions
Rotax 914 heat removal prescription for maximum power operation (86 kW)
has
to reject 45 kW as follows:
30
kW through cooling radiator
9
kW through oil radiator
6
kW from cylinder barrel fins
Supercharger
factor = 912S/914 = 105/86 = 1.22
Under
the cowling.
As the
engine and exhaust system heat up they radiate more heat.
Stefan-Boltzmann
says: about 5 / 10^11 x T^4 kW/m^2, T in Kelvin.
Table -
T in Kelvin ('F) and corresponding radiation flux in kW/m^2 - :
700
(800'F) 12.0
800
(980'F) 20.5 - supercharger runs about 200 degrees cooler than turbo
900
(1160'F) 32.8
1000 (1340'F) 50.0 - turbo calcs
1100
(1520'F) 73.2
Estimate
of 800K area (4 primary exhaust pipes): 0.10 m2
Radiated
heat: 2 kW
Estimate
of 800K area (muffler, turbo): 0.15 m2
Radiated
heat: 3 kW
Say
another 5 kW to be removed from under the cowling.
Total (39 * 1.22) + 5 = 53 kW.
Estimated
exhaust gas energy 278 – 53= 225 Kw - that why a turbo is best for raw power
Assumptions
Similar
efficiency for direct and indirect - via liquid - air cooling:
Inlet
areas :
Cooling
inlet radiator 210 cm^2 (estimated)
Cylinder
barrel fins 20 cm^2 (estimate on diameter 5.0 cm)
Gear
door louvers 18 * 7.5 * 1 = 135 cm^2 (18 louvers total)
11 ml
gasoline per second with mass 11 * 0.7 g/s = 8.7 g/s
requires
about 14 * 8.7 = 121 g/s of air per second
Assumptions
Air velocity into ducts is 40% of
aircraft velocity
Specific
Gravity 1.25kg/m3 at sea level pressure
Climb best rate =
120 km/hr (33 m/s) worst case air flow
Inlet radiator
duct 210 cm/sq
Inlet supercharger
44 cm/sq
Specific heat
capacity air = 1005 Kj/kg/deg K
Specific heat
capacity water – 4.2 Kj/kg/deg K
Flow water = 73
l/min or 1.2 l/sec
Calculations:
Air flow supercharger
Air flow supercharger
Using Q = (a*v*0.4) * s.g. = g/sec
44 * 33 * 0.4 * 1.25 = 726 g/s
NACA 3'' od Duct [44 sq cms] will supply enough air
by a 6:1 margin
Air flow radiator inlet
210 * (33 * 0.4) =
2370 l/s climb
210 * (60 * 0.4) =
5040 l/s cruse
Assume required radiator
delta t = 10 deg /c (283 deg /K)
The
Specific Heat formula is: c
= ΔQ / (m × Î”T)
Where:
c: Specific Heat , in J/(kg.K)
ΔQ: Heat required for the temperature change, in J
ΔT: Temperature change, in K
m: Mass of the object, in kg
Where:
c: Specific Heat , in J/(kg.K)
ΔQ: Heat required for the temperature change, in J
ΔT: Temperature change, in K
m: Mass of the object, in kg
Theoretical capacity air
1.005 = Q/ (2.4 * 1.25) * 10
Q = 30 KW climb
dT = (Q / (Heat output turbo x Supercharger factor)) * target radiator
= (30 / 39 x 1.22) * 10 = 6.2 deg C
= (30 / 39 x 1.22) * 10 = 6.2 deg C
1.005 = Q/ (5.0 x 1.25) * 10
Q = 63 kW cruse
dTmax = 63 / 48 x 10 = 13.1 deg C
Theoretical capacity water
4.2 = Q/ (1.2 * 1) * 10
Q = 50 kW
Q = 50 kW
Sunday, 18 December 2016
Merry Christmas 2016
Were are we now?
Currently I am moving from front to rear completing all areas to be ready for that final check and adjustment. The wings are nearly kitted out awaiting installation of the tanks and finally the skins. A final task to be finished is the fuel connections to the external tanks which have yet to be finalized by myself and the factory.
In July I began to experience extreme pain in my ankles and this was put down to old age and working on floors at 2 deg C. After the boys from the factory left is got worse but work on I did with ever decreasing output.
Finally went to a doctor and after the usual tests it was diagnosed the membrane on the underside of the foot was damaged annoying the nerves and resulting in inflammation at the ankles. Cure is rest, meaning no power walking of any kind for the next six months plus a month on anti-inflammatory's.
Thank God for miracle of modern medicine as good health it the most precious commodity next to time in the world.
Next Year?
The goal is to finish the fuselage to the nose, close the wing and paint the air frame.
The goal is to finish the fuselage to the nose, close the wing and paint the air frame.
 |
| Merry Christmas to all |
Thursday, 11 February 2016
Engine Cooling Ideas
This blog covers the background behind a Rotax cooling system design
Overview
This builder would like see what the effect of closing up the front door would have on the Tucano. To do this requires a solid foundation as currently the gear opening is the primary means for ejecting the waste heat from the radiator, oil cooler, exhaust and other minor sources. It is hoped that this would remove a perceived source of drag as well as some cooling drag - maybe.
All the reading says that air outlet's have to be twice the size of the radiator area based on heating the air. This did not have a convincing ring and seemed to be a easy way of solving the problem.
John Thorpe stated in one of his many articles on his design philosophy for light aircraft that the largest drag left in T18 was cooling drag but required careful design due to the danger of overheating.
Minds much more qualified have discussed this issue in great detail but the short article below outlines the basis of the my current opinion.
Research
In roving I can across a article on the Merdith Effect used as the basis for the design on the P51 cooling system. The most interesting comment was that at full power at altitude the outlet was squeezed down to 5'' square - See article: Merdith Effect fact or fiction.
Position A: High speed air with ram pressure enters the diffuser
Position B: Air is slowing, pressure rising as the diffuser cross-section area increases.
Position C: Air is at minimum speed and highest pressure on entering the radiator.
Position D: Air has been heated on passage through the radiator. Pressure falls a little due to viscous losses in the radiator.
Position E: Thermodynamic expansion is taking place in the nozzle. Temperature of the air is falling as the heat energy content is converted to kinetic energy. Pressure is falling as the air speeds up down toward the exit.
Position F: Adjustable exit scoop is set for high speed flight. Temperature of the air is much reduced, but not all of the heat can be turned into kinetic energy. Pressure is close to ambient, while the exit velocity is close to matching the airspeed of the airplane. The momentum change going from radiator rear face to the exit is seen as thrust, cancelling the drag of the radiator.
Position G: The scoop is wide open for low speed operation, where the cooling needs must be met by low velocity of the air at position A. No thrust generated due to low pressure rise in the diffuser.
Beign forced to dabble in Bernoulli a long time ago it did have a ring of truth. More roving lead to a discussion at of all places a car blog that was saying the same things.
The first diagram below shows what I would believe is happening with a lot of radiators installations. Air is like any fluids and dose not like work and will seek the path of least resistance so if nothing else a radiator hung on front of a engine with a big hole in front as its only protection it will be inefficient by the air looking for a easy way out - aka a big hole in the back of the cowl.
Extract: "Then what you want is a Kuchemann & Weber trumpet shaped diffuser. The name comes from a couple of scientists, Kuchemann & Weber performed a lot of R & D on this subject during World War II and published their findings in Aerodynamics of Propulsion sometime in 1953. These diffusers are highly utilized in aviation as well as in automotive racing.
Overview
This builder would like see what the effect of closing up the front door would have on the Tucano. To do this requires a solid foundation as currently the gear opening is the primary means for ejecting the waste heat from the radiator, oil cooler, exhaust and other minor sources. It is hoped that this would remove a perceived source of drag as well as some cooling drag - maybe.
All the reading says that air outlet's have to be twice the size of the radiator area based on heating the air. This did not have a convincing ring and seemed to be a easy way of solving the problem.
John Thorpe stated in one of his many articles on his design philosophy for light aircraft that the largest drag left in T18 was cooling drag but required careful design due to the danger of overheating.
Minds much more qualified have discussed this issue in great detail but the short article below outlines the basis of the my current opinion.
Research
In roving I can across a article on the Merdith Effect used as the basis for the design on the P51 cooling system. The most interesting comment was that at full power at altitude the outlet was squeezed down to 5'' square - See article: Merdith Effect fact or fiction.
Explanation of the P51 duct operation
Position A: High speed air with ram pressure enters the diffuser
Position B: Air is slowing, pressure rising as the diffuser cross-section area increases.
Position C: Air is at minimum speed and highest pressure on entering the radiator.
Position D: Air has been heated on passage through the radiator. Pressure falls a little due to viscous losses in the radiator.
Position E: Thermodynamic expansion is taking place in the nozzle. Temperature of the air is falling as the heat energy content is converted to kinetic energy. Pressure is falling as the air speeds up down toward the exit.
Position F: Adjustable exit scoop is set for high speed flight. Temperature of the air is much reduced, but not all of the heat can be turned into kinetic energy. Pressure is close to ambient, while the exit velocity is close to matching the airspeed of the airplane. The momentum change going from radiator rear face to the exit is seen as thrust, cancelling the drag of the radiator.
Position G: The scoop is wide open for low speed operation, where the cooling needs must be met by low velocity of the air at position A. No thrust generated due to low pressure rise in the diffuser.
Beign forced to dabble in Bernoulli a long time ago it did have a ring of truth. More roving lead to a discussion at of all places a car blog that was saying the same things.
The first diagram below shows what I would believe is happening with a lot of radiators installations. Air is like any fluids and dose not like work and will seek the path of least resistance so if nothing else a radiator hung on front of a engine with a big hole in front as its only protection it will be inefficient by the air looking for a easy way out - aka a big hole in the back of the cowl.
Extract: "Then what you want is a Kuchemann & Weber trumpet shaped diffuser. The name comes from a couple of scientists, Kuchemann & Weber performed a lot of R & D on this subject during World War II and published their findings in Aerodynamics of Propulsion sometime in 1953. These diffusers are highly utilized in aviation as well as in automotive racing.
Tuesday, 22 December 2015
Merry Christmas 2015
Well its years end and this builder has no idea where it all went. Like all builder's I hoped to have more completed but taking time to review the blog dose provide some reassurance that a lot of work was completed.
Next Year?
The cockpit area will begin to take form clarifying the design philosophy outlined over the past year and the quick build wing kit will be mated to the fuselage allowing those two areas to begin their assembly.
Were are we now?
A lot of tasks are nearly complete and I hope to finally install the rudder and elevators in the New Year once a few small outstanding tasks are complete. It is amazing how long it takes to do the really small things well and to source and take delivery of that final do hicky thing.
At this point I am off for a holiday with the family and will not be back at work until the third week of January but will finish off some of the ten or so blogs in draft form. My hope is that the readers found something of value in the past year and excuse me for some poor grammar.
Next Year?
The cockpit area will begin to take form clarifying the design philosophy outlined over the past year and the quick build wing kit will be mated to the fuselage allowing those two areas to begin their assembly.
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Merry Christmas and a Happy New Year from Australia to all |
Saturday, 1 November 2014
Frank Walter Cale Pilot Officer
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| Spit-tano |
The paint scheme chosen is the 2010 RAF- 50th Anniversary Battle of Britain Tucano demonstration team aircraft and it was decided to create an Australian link. [See: Styling]
UO was the prefix for 266 squadron in 1940 and H appears on the grave marker Most aircraft carried UO with no unique ID due to the loss rate at the time.
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| Spitfire MK1 flown by Walter Cale |
His aircraft was a Spitfire Mk 1A serial number N3168, construction number 410.
Why Frank Cale? - Like a lot of the unknown pilots, he lost his life paying the price for our collective attraction for evil men while receiving none of the public glory associated with the victorious but known in history as "One of the Few".
WAR RECORDS
On the 15th of August, the 266 Squadron scrambled against a Luftwaffe raid and were heavily engaged over Kent. In a stiff fight, the 266 lost Pilot Officer Frank W. Cale was shot down in his Spitfire Mk 1 (N3168) near Maidstone, Kent at 18:50 hrs. He was seen to bale out and his parachute opened.
However, all that could be located on the ground was his parachute with burnt straps. Cale's body was recovered from the River Medway on the 16th of August 1940.
However, all that could be located on the ground was his parachute with burnt straps. Cale's body was recovered from the River Medway on the 16th of August 1940.
He was aged 25 when he joined the Few.
Combat Report lodged by F. Cole 2nd June 1940
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