# Look for airplane design: Take off@12000 feet

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#### gouxin

##### Active Member
Why? Very simple: I want to fly in the Tibetan area and bring up kids in that area to let them see their hometown from an aspect where they've never seen before. To realize this dream I need an airplane with the following attributes:
1. be able to take off with two on board and some fuel at 12000 feet(this is just the start point of Tibetan area) with takeoff distance less than 1500 feet.
2. two seater
3. folding wings or easily removable wings (this is a must requirement for flying in that area).
4. relatively low cost to acquire and operate.

It seems turbo charged engine and light wing loading should make this happen. I understand turbo engine should work with constant speed prop but since the mission profile of this airplane is limited to high altitude most of the time, I can use a ground adjustable prop and set the pitch to high altitude use most of the time so constant speed prop is not a requirement.

How about a two-seat quicksilver or Xenos motorglider fitted with HKS 700T or turbo VW engine?

This is not a hanger talk or daydreaming. My friends and I are going to do it.

Xin Gou
From Chengdu, China

#### Joe Fisher

##### Well-Known Member
One thing is high altitude is only part of your challenge. Near the ground you will find ex stream turbulence and the control and performance of an ultralight type aircraft will not be able to keep it from being slammed into the ground. Be careful and study about mountain flying.

#### TFF

##### Well-Known Member
Over Everest; Emil Wick
The tough part is 12,000 ft was a close to world record landing hight up until the 70's.

#### Aircar

##### Banned
Having done a study on the feasibility of operating a special design aircraft into Humla province (@ 4000M altitude) I can say that it is a very difficult task and a Quicksilver or xenos will be limited to at the very best one seat --and need a large prop diameter etc etc --the air density at 4000M is only 62% of sea level so plug that into your Lift formula and then add your 50ft obstacle clearance for take off distance and I think you are going to be out of the ballpark --and the question is WHERE can you find a 1500 ft strip above 12000 ft in Nepal ? (there is a video subtitled "the world's most dangerous airport?" --the name is short , something like Lukhsa --which shows landing and take offs in the Nepalese hinterland --a well sloped strip and one way only and reverse thrust needed on landing but admittedly these are for turboprop commuter aircraft --New Guinea is very similar in terms of terrain and to a lesser degree altitude and also features lots of 'impossible' airstrips . Lots of power and turbocharging would help a great deal at these heights and I suspect that the weight and balance on something like a Xenos will be an issue for adding a lot more power --the ideal aircraft will have both very low wingloading and span loading , a very big prop etc at least in it's landing and take off configuration.

there is in my view a need for an aircraft with the sort of high altitude capability involved here (and STOL @ that height ) --for such places as Bolivia,New guinea and other poorly served communities in mountainous terrain (which means no roads also )

Good luck with your efforts .

#### litespeed

##### Well-Known Member
A very hard ask but will also depend on your ability to get fuel and in quantites to suit the aircraft needed.

Why you really need folding wings or removable ? That can really limit the available aircraft designs that will suit.

I think you really need -

something with low weight, big power, STOL abilities and a big wing area.

how about a Criquet Storch with a minimum of a turbo rotax?

Or a Hornet from AAK with similar engine or even better the turboprop he has available?

These are the sort of aircraft needed- tough,light,powerful and STOL.

#### gouxin

##### Active Member
thanks for the reply. Now it seems turbine is the way to go, but there's no way I can afford that for now. The reason for folding or removable wings is that private flying is still very restricted in China and we have to trailer the airplane into the area and take the "fly and go" approach.

##### Well-Known Member
Why not one of the "conventional" STOL-designs? CH701/750/801?

#### topspeed100

##### Banned
I just made some sketches for a very small ac with high AR...I figured it cannot do the speed record...but it looks like it could be ok for high altitude flying.

I also acquired an aerodynamics book today and possibly I could figure out how high it could soar with the longer wings ( originally tought 2 pair of wings for different purposes ).

This would be very aerodynamical and lite 3 seater with optional 4th seat bench at the rear ( or 80 lbs luggage ).

How busy are you with it ?

#### Dana

##### Super Moderator
Staff member
A powered paraglider trike might do it, though you'd be limited to rare light wind conditions... though just anything that could take off in the distance and altitude you specify would be similarly limited.

-Dana

"No man's life, liberty, or property is safe while the legislature is in session." (Judge Gideon J. Tucker, 1866)

#### Hot Wings

##### Grumpy Cynic
HBA Supporter
Log Member
Since cruise speed doesn't seem to be a high priority, rather than a fixed wing airplane how about a blimp?

#### topspeed100

##### Banned
TFF wrote;

Code:
[URL="http://www.flymicro.com/everest/index.cfm?page=docs/History/Emil_Wick.htm"][COLOR=#417394]Over Everest; Emil Wick[/COLOR][/URL]
The tough part is 12,000 ft was a close to world record landing hight up until the 70's.

Interesting since I planned this my design to have fully retractable main ski !

So 5700 meters is the highest man has ever landed and taken off with fixed wing ac.

This is the engine for the Himalaya/Tibetian operations for a low cost mountain "soarer".

Rotax 914 UL specifications, performance, weights and documentation

Another engine where the turbo is better positioned for aerodynamics; Limbach-Flugmotoren.de - L 2400 DT.X

Rotax 914 ULS otoh has smaller overall size...they could be even in "drag forming shapes".

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#### gouxin

##### Active Member
Yes, Tibet is right next to Nepal.I think it's OK to have a CH701 type STOl airplane equipped with turbo engine for now, restricted to relatively calm weather condition of course.

#### topspeed100

##### Banned
Where is the highest possible landing strip over at Himalayas ? For a skiplane I mean ?

#### gouxin

##### Active Member
Bangda airport in eastern Tibet, which lies 15,548 feet above sea level, is the highest airport in the world, if that's what you were asking. If your skiplane is capable enough, there're plenty of flat and straight open wild fields as landing strip above this height.

#### topspeed100

##### Banned
Ok..I once had a uni ski R/C model place of my own design..it was the most fun modelaeroplane I ever had. The ski can be made to create lift unlike the wheel.