Hi all,
i'm picking up where i left off with my single seat, single engined microlight but have made some changes, and changed some specs.
Here's what i need:
-Daily commuter from airport one (EGPN) to airport 2 (EGPT), 5 days a week. (because i'm fed up of rush hour traffic for one!)
I'd like to do this trip in about the same time as i can in my car...30 miles on the road, 25 'as the crow flies' takes me around 45mins by road. But this is to include pre-flight etc, so additional tasks like assembling things isn't going to help. saying that, i'd like folding wings or a very simple detach and attach mechanism for transport.
-Weekend fun - I love the soaring videos posted here, and with the cairngorms national park on my doorstep, it looks like fun! so maybe heading towards motorglider. i understand this will make the aircraft a compromise (average motorglider, average commuter aircraft) but i cant afford two, so thats the way it's gotta be! for this i'd also like some grass strip ability for some of the little island strips on the west coast.
What i'd like:
- low maintenance costs
- Trailerable
- A Testbed for a hybrid system in the future (just too expensive at the moment, but i'd like to be able to convert it in the future)
- The ability to fly safely in an engine out situation
- economical cruise around 130kts
- high speed cruise around 160kts
Regulatory Requirements:
- Stall speed or minimum level flight speed with flaps deployed of 35kts
- MTOW 300kg
Having looked at other aircraft, i'd set the empty weight target at 120kg.
I got onto the twin idea as i went through a phase of wanting a cricri, but needed to reduce the stall speed, and then wanted to make it composite...and it looked like more work than designing from scratch so thats what i'm doing.
I weigh around 70kg, and i'm 6'1", don't think anyone else will be getting a shot in the near future so that's the design pilot, add 10kg because i'm young and will likely get a belly one day, so 80kg.
i also need my bag with laptop etc for uni, plus some additional odds and ends... so lets say 10kg max luggage to give some margin (realistically it will be about 5kg)
fuel for daily commute should be no more than 2 gallons + reserve + i might go for a wee detour if i get up early, so lets say a 10 gallon tank which will likely never be filled to the brim, but if it is i should get a decent range (UK wide, and as SSDR's cant fly outside UK that's as good as it can get) - so thats 33kg max
MTOW would work out as:
120kg
+ 80kg
+ 10kg
+ 33kg
---------------------
= 244kg
I'll add 10kg for calculations sake, so i don't build something and then find it doesn't reach the stall limit and is useless, and round it up by 1 for good luck:
Design weight = 255Kg
Constuction will be 'rutan method' glass over foam. I'll be using glass instead of graphite for the cost, and secondly because i don't have an autoclave or any experience with carbon, but i've used glass plenty.
from basic sketches, loads of reading and some trial and error i've come to this as my starting point:
Length: 5m
span: 8.4m
chord: (average) 0.7m
Aspect Ratio: 12
Landing gear: retracting tri-gear
Flaps: slotted fowlers and leading edge slats to drop the stall speed - though this might change as the X-plane model is stalling nicely at 37kts at 290kg (overweight)
Engines: 2 wing mounter injected recip: 25hp each with fixed pitch props (tractor)
*the engines are 2m apart, which results in both being quite close to the centerline and ideally i'd fold or detach the wings after this point to leave the fuselage with wing roots and engines under 2.3m (max towing width in UK)
Anyway...x-plane model screenshots as usual:
Comments and critics welcome
i'm picking up where i left off with my single seat, single engined microlight but have made some changes, and changed some specs.
Here's what i need:
-Daily commuter from airport one (EGPN) to airport 2 (EGPT), 5 days a week. (because i'm fed up of rush hour traffic for one!)
I'd like to do this trip in about the same time as i can in my car...30 miles on the road, 25 'as the crow flies' takes me around 45mins by road. But this is to include pre-flight etc, so additional tasks like assembling things isn't going to help. saying that, i'd like folding wings or a very simple detach and attach mechanism for transport.
-Weekend fun - I love the soaring videos posted here, and with the cairngorms national park on my doorstep, it looks like fun! so maybe heading towards motorglider. i understand this will make the aircraft a compromise (average motorglider, average commuter aircraft) but i cant afford two, so thats the way it's gotta be! for this i'd also like some grass strip ability for some of the little island strips on the west coast.
What i'd like:
- low maintenance costs
- Trailerable
- A Testbed for a hybrid system in the future (just too expensive at the moment, but i'd like to be able to convert it in the future)
- The ability to fly safely in an engine out situation
- economical cruise around 130kts
- high speed cruise around 160kts
Regulatory Requirements:
- Stall speed or minimum level flight speed with flaps deployed of 35kts
- MTOW 300kg
Having looked at other aircraft, i'd set the empty weight target at 120kg.
I got onto the twin idea as i went through a phase of wanting a cricri, but needed to reduce the stall speed, and then wanted to make it composite...and it looked like more work than designing from scratch so thats what i'm doing.
I weigh around 70kg, and i'm 6'1", don't think anyone else will be getting a shot in the near future so that's the design pilot, add 10kg because i'm young and will likely get a belly one day, so 80kg.
i also need my bag with laptop etc for uni, plus some additional odds and ends... so lets say 10kg max luggage to give some margin (realistically it will be about 5kg)
fuel for daily commute should be no more than 2 gallons + reserve + i might go for a wee detour if i get up early, so lets say a 10 gallon tank which will likely never be filled to the brim, but if it is i should get a decent range (UK wide, and as SSDR's cant fly outside UK that's as good as it can get) - so thats 33kg max
MTOW would work out as:
120kg
+ 80kg
+ 10kg
+ 33kg
---------------------
= 244kg
I'll add 10kg for calculations sake, so i don't build something and then find it doesn't reach the stall limit and is useless, and round it up by 1 for good luck:
Design weight = 255Kg
Constuction will be 'rutan method' glass over foam. I'll be using glass instead of graphite for the cost, and secondly because i don't have an autoclave or any experience with carbon, but i've used glass plenty.
from basic sketches, loads of reading and some trial and error i've come to this as my starting point:
Length: 5m
span: 8.4m
chord: (average) 0.7m
Aspect Ratio: 12
Landing gear: retracting tri-gear
Flaps: slotted fowlers and leading edge slats to drop the stall speed - though this might change as the X-plane model is stalling nicely at 37kts at 290kg (overweight)
Engines: 2 wing mounter injected recip: 25hp each with fixed pitch props (tractor)
*the engines are 2m apart, which results in both being quite close to the centerline and ideally i'd fold or detach the wings after this point to leave the fuselage with wing roots and engines under 2.3m (max towing width in UK)
Anyway...x-plane model screenshots as usual:
Comments and critics welcome
