I recently joined HBA. I have posted a couple tangential references to this but now I will start a thread.
I have recently retired and am researching building a sport pilot legal airplane. The mission is to take two people and 40 lbs of baggage at least 300 miles at nearly 120 knots. This mission is already accomplished by several low wing kit aircraft. I want a basic high wing side by side aircraft for less than a $40,000 budget. A cruise speed similar to my Cherokee 180’s is the goal. The high wing and high cruise speed are the design features of this plane that are not found in an all metal homebuilt aircraft. The CH 750 Cruzer is too heavy with too large of a wing to achieve this goal. The Buttercup could come closer with some modifications but it would not be a Buttercup and it is tube and fabric.
If money was not a factor I would own a Pipistrel Virus SW. The plane that most closely fits the following description except for the homebuilt part and price point is the Flightdesign MC. It is mostly aluminum with a strut braced wing. TECHNICAL INFORMATION
Here are my desired specs. I have worked most of this out using the spread sheet associated with Dan Raymer’s book Simplified Aircraft Desgin for Homebuilders.
Power 100 hp Most likely Rotax 912
Wing area 117 with full span flaperons
Gross wt 1200 lbs
Empty wt 650 lbs
Stall 45 knots
Airfoil Riblett GA 37A415
Top speed 135 knots
Cruise SL 120 knots, max continuous rpm
Cruise 8k 120 knots, would need to exceed max continuous RPM.
Wing CL max 1.5 may need to rig the up stop on the flaperons down a couple degrees.
CL cruise 0.255
Wing loading 10.31 lbs/sq ft
Wing span 26 feet
Wing chord 4.5 feet
AR 5.78
Power loading 12 lbs/hp
Fuel capacity 24 gallons probably in wings
Assumptions:
SWet/Sref 4.2
Span efficiency .85
The empty weight is probably optimistic but the rest seems pretty plausible. I might need to bump up the wing area to 120 square feet. The plane must be kept small to achieve the speed. Something between a Sonex and an RV12 in size.
The most rational choices would be to compromise on the high wing and just build an RV12 with a used engine or compromise on the cruise speed and build a CH750 Cruzer. In other ways experimental flying is not necessarily rational. I want to explore this design more. The all metal wing would be built on a built up spar with stock extrusion spar caps and supported by a single strut. After some thought I have for the moment decided on a fuselage using BD4 type construction with a few more joints and of course a wing strut. It would still be a box but with a little more shape. Some changes would need to be made for weight and balance. I am aware that Jim Bede worked on a BD4 light sport but that design was never offered. The specs were a bit on the heavy side also.
This would be a one off. There is no intention of offering plans or any other business associated with this project.
Should I follow a dream or just follow the masses?
I have recently retired and am researching building a sport pilot legal airplane. The mission is to take two people and 40 lbs of baggage at least 300 miles at nearly 120 knots. This mission is already accomplished by several low wing kit aircraft. I want a basic high wing side by side aircraft for less than a $40,000 budget. A cruise speed similar to my Cherokee 180’s is the goal. The high wing and high cruise speed are the design features of this plane that are not found in an all metal homebuilt aircraft. The CH 750 Cruzer is too heavy with too large of a wing to achieve this goal. The Buttercup could come closer with some modifications but it would not be a Buttercup and it is tube and fabric.
If money was not a factor I would own a Pipistrel Virus SW. The plane that most closely fits the following description except for the homebuilt part and price point is the Flightdesign MC. It is mostly aluminum with a strut braced wing. TECHNICAL INFORMATION
Here are my desired specs. I have worked most of this out using the spread sheet associated with Dan Raymer’s book Simplified Aircraft Desgin for Homebuilders.
Power 100 hp Most likely Rotax 912
Wing area 117 with full span flaperons
Gross wt 1200 lbs
Empty wt 650 lbs
Stall 45 knots
Airfoil Riblett GA 37A415
Top speed 135 knots
Cruise SL 120 knots, max continuous rpm
Cruise 8k 120 knots, would need to exceed max continuous RPM.
Wing CL max 1.5 may need to rig the up stop on the flaperons down a couple degrees.
CL cruise 0.255
Wing loading 10.31 lbs/sq ft
Wing span 26 feet
Wing chord 4.5 feet
AR 5.78
Power loading 12 lbs/hp
Fuel capacity 24 gallons probably in wings
Assumptions:
SWet/Sref 4.2
Span efficiency .85
The empty weight is probably optimistic but the rest seems pretty plausible. I might need to bump up the wing area to 120 square feet. The plane must be kept small to achieve the speed. Something between a Sonex and an RV12 in size.
The most rational choices would be to compromise on the high wing and just build an RV12 with a used engine or compromise on the cruise speed and build a CH750 Cruzer. In other ways experimental flying is not necessarily rational. I want to explore this design more. The all metal wing would be built on a built up spar with stock extrusion spar caps and supported by a single strut. After some thought I have for the moment decided on a fuselage using BD4 type construction with a few more joints and of course a wing strut. It would still be a box but with a little more shape. Some changes would need to be made for weight and balance. I am aware that Jim Bede worked on a BD4 light sport but that design was never offered. The specs were a bit on the heavy side also.
This would be a one off. There is no intention of offering plans or any other business associated with this project.
Should I follow a dream or just follow the masses?
