Homebuilt VLJ ...good idea ?

HomeBuiltAirplanes.com

Help Support HomeBuiltAirplanes.com:

topspeed100

Banned
Joined
May 4, 2009
Messages
4,063
Location
Oulu/Finland
Here is mine from this morning.

Uber rectancular almost blended body...and tightly packed and highly reclined seating.

Nearly 2 x faster than 4 seater Eclipse400 ( with 2 x power too ).

Could this be the key to solve the slow interest on VLJs ?

Really fast carbon ship ( 900 km/t cruise ).
 

Attachments

Aviator168

Well-Known Member
Joined
Sep 21, 2012
Messages
2,214
Location
Brookville, NY. USA
Bad idea. Why do you put the pax in a row? Beside, I think your canard is too small. You have to study why the eclipse fail as a product. I think it comes down to one thing -- toilet. Any plane (>3 place) that need to fly more than 4 hours without a toilet will not make it.
 

topspeed100

Banned
Joined
May 4, 2009
Messages
4,063
Location
Oulu/Finland
Bad idea. Why do you put the pax in a row? Beside, I think your canard is too small. You have to study why the eclipse fail as a product. I think it comes down to one thing -- toilet. Any plane (>3 place) that need to fly more than 4 hours without a toilet will not make it.
Good point. Therefore this is fast that you could travel longer distance in the few hours the fuel runs out.

I am also hoping to make it so efficient that it could supercruise like mach 1.2.
 

Birdman100

Well-Known Member
Joined
Jun 12, 2013
Messages
807
Location
Novi Sad, Vojvodina
The passenger area looks to small, especially the cross section. If you want people like your plane you dont want them to feel claustrofobic:dis:. I know that you have done that to minimise parasite drag but this just looks too small. If you make fuselage cross section circular you will have more space, little bit more drag but also the shape that is much more resistant to pressure diference
 

Birdman100

Well-Known Member
Joined
Jun 12, 2013
Messages
807
Location
Novi Sad, Vojvodina
Bad idea. Why do you put the pax in a row? Beside, I think your canard is too small. You have to study why the eclipse fail as a product. I think it comes down to one thing -- toilet. Any plane (>3 place) that need to fly more than 4 hours without a toilet will not make it.
I think canard is not too small. You want fast plane with the smallest drag possible. Every aerodynamic surface beside the wing has less aerodynamic efficiency so you want it rellatively small especially in this case. In canard configuration wing is stabilizer.
 

topspeed100

Banned
Joined
May 4, 2009
Messages
4,063
Location
Oulu/Finland
Have you consider a blended wing configuration?
In fact this is sorta mild blended wing design.

As you can see below the numbers don't lie.

When divided the power of the Bravo PW530As with size ratio this smaller beats it by 9% in power..but since this is a 1000 km/t design it'll go 25% faster.

This is tight like a glider to sit in..but comfortable as you get used to it.

http://www.jetsales.com/comp/types/jets/bcitationbravo.html

So cruise around 490 KTAS ( as estimated ). Range in par with Lear Jet 35/36A => 1995 nm.

I figure there could be a jump seat for a child ( person max 50 kg ) in front of the back seated. Thus 2+5 max seating.

Luggage behind the back seated around 150-200 liters.
 

Attachments

Last edited:

Apollo

Well-Known Member
Joined
Feb 7, 2010
Messages
301
Location
Southern California, USA
Here is mine from this morning.

Uber rectancular almost blended body...and tightly packed and highly reclined seating.

Nearly 2 x faster than 4 seater Eclipse400 ( with 2 x power too ).

Could this be the key to solve the slow interest on VLJs ?

Really fast carbon ship ( 900 km/t cruise ).
I agree - this is an excellent design that can resolve the slow interest in VLJs. You've clearly put a lot of thought into the design and it should have very high performance. You should invest your life's savings and all of your time and energy into building this aircraft.
 

Birdman100

Well-Known Member
Joined
Jun 12, 2013
Messages
807
Location
Novi Sad, Vojvodina
I agree - this is an excellent design that can resolve the slow interest in VLJs. You've clearly put a lot of thought into the design and it should have very high performance. You should invest your life's savings and all of your time and energy into building this aircraft.
Who dares, wins:ban:
 

topspeed100

Banned
Joined
May 4, 2009
Messages
4,063
Location
Oulu/Finland
I agree - this is an excellent design that can resolve the slow interest in VLJs. You've clearly put a lot of thought into the design and it should have very high performance. You should invest your life's savings and all of your time and energy into building this aircraft.
Since it carries 7 there is still room for 6 others...or if we "socialize" it maybe 13 more..or 20 etc ( repeat this until the investment suits your wallet ). Depends also how often you wanna fly.

Any idea what pair of PW615Fs cost ?

http://www.pwc.ca/en/engines/pw615f-a
 
Last edited:

topspeed100

Banned
Joined
May 4, 2009
Messages
4,063
Location
Oulu/Finland
I think canard is not too small. You want fast plane with the smallest drag possible. Every aerodynamic surface beside the wing has less aerodynamic efficiency so you want it rellatively small especially in this case. In canard configuration wing is stabilizer.

I increased and then reduced it to 15% of the main wing.
 

Aviator168

Well-Known Member
Joined
Sep 21, 2012
Messages
2,214
Location
Brookville, NY. USA
In fact this is sorta mild blended wing design.

As you can see below the numbers don't lie.

When divided the power of the Bravo PW530As with size ratio this smaller beats it by 9% in power..but since this is a 1000 km/t design it'll go 25% faster.

This is tight like a glider to sit in..but comfortable as you get used to it.

Citation Bravo Performance Specifications and Photo

So cruise around 490 KTAS ( as estimated ). Range in par with Lear Jet 35/36A => 1995 nm.

I figure there could be a jump seat for a child ( person max 50 kg ) in front of the back seated. Thus 2+5 max seating.

Luggage behind the back seated around 150-200 liters.
Are people willing to get into your plane packed like cattles?
 

Doggzilla

Well-Known Member
HBA Supporter
Joined
Jun 2, 2013
Messages
2,325
Location
Everywhere USA
The whole problem with the current choice in planes is this "all or nothing" approach. Almost every design has a major flaw.

For instance, the Cessna 172 has 4 seats, even though it can barely lift 2 adults and a child with any useful fuel. It also cannot use the large internal area to haul thing. The aircraft is designed for a scenario which happens about 1-2% of the time.
If the 172 was designed for its capability, there would be one fold out rear seat, and it would have a sliding door so the pilot could actually haul something useful, like a grill or other light but voluminous gear.

Like Ive said before, I drive a truck, and we can have an entire 53 foot trailer filled with commercial goods....and it weight 10,000 lbs. Planes need to make better use of volume. This is why the 208 needs a belly pack, even IT is too small.

There there are planes which cant decide what they want to be, so cut off any extra utility for no gain in performance. Pipers are this way. They arent a Mooney, but they dont utilize the additional lift and volume they traded the speed for.

VLJ are the same way. Who the hell would use a VLJ as a sardine can? VLJ is not about the value, its about the freedom and the power. A leerjet cannot do what a VLJ can. The VLJ is the UBER-GA aircraft, its the ferrari of the sky. Leer jets are Rolls Royce. Some people want a Ferrari over a Rolls. For that reason, these VLJ which cram people together are not attractive to buyers. They might as well just fly business.

VLJ will be successful when they realize that owners want performance and usefulness. They arent going to take 6 people, they want to have leg room and to bring back the goods they just bought in New York. It has to be hot, fast, fun, and useful in context.

Current aircraft almost universally do not perform what the owners wish they did. Most designs do not perform well in any one way, some do one job decently, but most aircraft trade in one spec for useless performance in others.
 

Aviator168

Well-Known Member
Joined
Sep 21, 2012
Messages
2,214
Location
Brookville, NY. USA
VLJ are the same way. Who the hell would use a VLJ as a sardine can? VLJ is not about the value, its about the freedom and the power. A leerjet cannot do what a VLJ can. The VLJ is the UBER-GA aircraft, its the ferrari of the sky. Leer jets are Rolls Royce. Some people want a Ferrari over a Rolls. For that reason, these VLJ which cram people together are not attractive to buyers. They might as well just fly business.

VLJ will be successful when they realize that owners want performance and usefulness. They arent going to take 6 people, they want to have leg room and to bring back the goods they just bought in New York. It has to be hot, fast, fun, and useful in context.

The Velocity planes fill this role very well. Too bad they are not jets.
 

PTAirco

Well-Known Member
Joined
Sep 20, 2003
Messages
3,528
Location
Corona CA
The headroom is so minimal that, unless you have a door for every seat, your passenger will have to crawl on hands and knees to get into their seat. Very awkward.
 

Aircar

Banned
Joined
Feb 20, 2010
Messages
3,567
Location
Melbourne Australia
Not only is entry and exit virtually impossible (especially if pressurized) I don't think you will have anywhere to carry fuel (the wing is too far aft for that from balance and anyway too small ) The LearFAN was developed along these lines long before the resurgence in very light jets and was deficient inn wing volume which was only one damning fault. Floating a 'concept' is all well and good but lightyears from having even a concept that is viable only in principle even.
 

Aerowerx

Well-Known Member
Joined
Dec 1, 2011
Messages
5,568
Location
Marion, Ohio
I am also hoping to make it so efficient that it could supercruise like mach 1.2.
Not over most of the United States! Sonic Booms are prohibited.

The fastest commercially available civilian plane is the Cessna Citation X, which only does mach 0.8. And they went to great pains to get a perfecly smooth laminar flow wing.
 

Aircar

Banned
Joined
Feb 20, 2010
Messages
3,567
Location
Melbourne Australia
Topspeed - my last post might have seemed a bit harsh -I only had a ten minute slot on a library "standby' computer which also includes the time to type in library member ref nos. and then get to google,type HBA ID and password etc so it was a clock ticking deadline set up (time yourself in doing a typical post read and reply ..)

JT Airco was being usefully critical in his observation - I think Apollo was being sarcastic ("spend all your savings etc" ) but also had a truth in his response --there are so many stillborn aircraft and especially when one deviates from the well worn path of conventionality to dissuade anyone from ever thinking of designing anything ever again so that the very existenmce of this website is an anomaly . EAA has seemingly dropped any pretence to be fostering the design of experimental aircraft and settled into a senescence almost with antique and 'golden days' re enactments top of the agenda . ( I looked up the last couple of years of Sport Aviation on line just a few days back and reminded myself why I didn't renew my membership --pathetic stories that belong in the AOPA or Flying mags as operator related and space giving over to the "airport bomb of the month" for goodness sake [old 'courtesy cars' left for intinerant aircraft users ] --no space in the inn for flying cars though .

Getting hold of Raymer's encyclopedic set of books on Airplane design is probably the best advice for budding designers --maybe it is available on CD or someother computer subscription now --his work is the best and most easily read for general conceptual design and will save a lot of "what do you think..?" type stuff for unformed ideas ( I luckily got the whole set from a second hand bookshop just closing down for about 10% of the list price --just managed to get them on my bicycle rack but it was horribbly unstable with so much weight high up and aft --as the text could have predicted..) The WORST area for unthought- through design is in FLYING CARS and this drives me to apoplexy because so many absolutely boneheaded mistakes are glaringly obvious in them but they are promoted to a gullible and ignorant public and, even worse, with pleas for big money. The whole of aviation ,and invention, suffers by association.


I just finished reading "Aloft' by William langeswieche - highly reccomended and more so as it is written to a general audience not just flying fanatics -- he describes the 'flying gin palaces' and obscenely wasteful executive jets in those terms and leaves little doubt where he stands on the 'need' for such aircraft to even exist (and the 'supersonic business jet' is another hyped up tax dodging excess also lampooned by Peter garrison even if he can admire some of the technicalities involved --- talking about Mach Nos for personal aircraft is overkill of the highest order .
 

topspeed100

Banned
Joined
May 4, 2009
Messages
4,063
Location
Oulu/Finland
Topspeed - my last post might have seemed a bit harsh -I only had a ten minute slot on a library "standby' computer which also includes the time to type in library member ref nos. and then get to google,type HBA ID and password etc so it was a clock ticking deadline set up (time yourself in doing a typical post read and reply ..)

JT Airco was being usefully critical in his observation - I think Apollo was being sarcastic ("spend all your savings etc" ) but also had a truth in his response --there are so many stillborn aircraft and especially when one deviates from the well worn path of conventionality to dissuade anyone from ever thinking of designing anything ever again so that the very existenmce of this website is an anomaly . EAA has seemingly dropped any pretence to be fostering the design of experimental aircraft and settled into a senescence almost with antique and 'golden days' re enactments top of the agenda . ( I looked up the last couple of years of Sport Aviation on line just a few days back and reminded myself why I didn't renew my membership --pathetic stories that belong in the AOPA or Flying mags as operator related and space giving over to the "airport bomb of the month" for goodness sake [old 'courtesy cars' left for intinerant aircraft users ] --no space in the inn for flying cars though .

Getting hold of Raymer's encyclopedic set of books on Airplane design is probably the best advice for budding designers --maybe it is available on CD or someother computer subscription now --his work is the best and most easily read for general conceptual design and will save a lot of "what do you think..?" type stuff for unformed ideas ( I luckily got the whole set from a second hand bookshop just closing down for about 10% of the list price --just managed to get them on my bicycle rack but it was horribbly unstable with so much weight high up and aft --as the text could have predicted..) The WORST area for unthought- through design is in FLYING CARS and this drives me to apoplexy because so many absolutely boneheaded mistakes are glaringly obvious in them but they are promoted to a gullible and ignorant public and, even worse, with pleas for big money. The whole of aviation ,and invention, suffers by association.


I just finished reading "Aloft' by William langeswieche - highly reccomended and more so as it is written to a general audience not just flying fanatics -- he describes the 'flying gin palaces' and obscenely wasteful executive jets in those terms and leaves little doubt where he stands on the 'need' for such aircraft to even exist (and the 'supersonic business jet' is another hyped up tax dodging excess also lampooned by Peter garrison even if he can admire some of the technicalities involved --- talking about Mach Nos for personal aircraft is overkill of the highest order .
That is true the mach 1.2 at supercruise needs nozzle designing and goes well beyond the capabilities of a homebuilder.

Also entering the ship is somewhat arduous and exiting might require extra hole above the pilots, but it has to be like this if you wanna fast with a VLJ.

Concept has to be 1000 km/t region design with sweep etc. in order to go fast with just 10 kN of thrust.
 
Top