# single seat, composite, ultralight STOL - would you like it?

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#### BJC

##### Well-Known Member
HBA Supporter
The weather is all about where you are. Around where I live it was 8 C down at the fjord. Higher up it was snowing, actually quite a few mountain roads closed due to snow on what in the calendar is defined as the first "summer" day. The density altitude on the other side is great for flying.
I'm sitting in Tampa International Airport, headed to England, then, in a few days, on to Norway via cruise ship.

Looking forward to visiting your country again.

BJC

#### Himat

##### Well-Known Member
Eduguessed specs:
*Empty: 120 kg (that's real empty, with a BRS, instruments, battery, fluids; a flying plane)
*Wing area: 5 m2
*Span 9 meters, with both outboard 2 meters folding
*Stall 38 kts typical
*35 hp
*Cruise, 80+ kts WOT
*Climb, over 1000 fpm WOT
Without the regulations in front of me, I think this is somewhat outside the US part 103 ultralight.
It probably fit better with the different European ultralight/microlight regulations.

#### Himat

##### Well-Known Member
I'm sitting in Tampa International Airport, headed to England, then, in a few days, on to Norway via cruise ship.

Looking forward to visiting your country again.

BJC
Do the cruise sail "Sognefjorden"?
If so you will sail by where I have a "summer" house.

I wish you a pleasant trip, but remember the word from a TV travel guide traveling the western part of Norway; if you get sun and warm weather you have been had.:gig:

BJC

#### Birdman100

##### Well-Known Member
Count on a 4-stroke. That doesn't exclude putting a 2-stroke on there, but if you reconsider (like many people) and later want to go 4-stroke... you better took it into account in the inital design.
Yep, you are right and it will eventually be like that. Personally I will go for 2-stroke, but it has to be "room" for 4-stroke. The weight is not that much issue itself but with the lighter pilot (say 60 kgs) in front, heavy engine back and with such light structure CG would be dangerously aft. Yes, done preliminary CG calculation. Oh, one more reason half a meter chord is bad idea in this case.

It's not "liking" or anything like that. Do the math and see how much lighter a longer wing is and how much less power you're pissing away in drag during climb
I did a lot of math and am perfectly aware of what you are talking about. But am simply ok with some consequences. For that reason I dont want for that plane to be underpowered (thus wish for such a light structure, two-stroke...), and am not up to extremely low fuel consumption. Your propositions fit to "21. century Volksplane" but this is another, more extreme category.

thanks for the photo, yes I saw it already, good to refresh memory. But how they access that from the side of wing, how attach the pin/bolt?

Am still not sure whether to go one-piece wing or two-pieces. Two-pieces would be easier to transport

#### Birdman100

##### Well-Known Member
I'm sitting in Tampa International Airport, headed to England, then, in a few days, on to Norway via cruise ship.

Looking forward to visiting your country again.

BJC
Have a nice trip! Some of my friends ended up in Norge (Norway) and they urge me to go there as well. There is probability I will eventually.

BJC

#### DangerZone

##### Well-Known Member
HBA Supporter
Imagine a small, very light, single seat all carbon fiber pusher STOL. It should be open cockpit (wind in the hair), with flight feeling similar to this shown in this VIDEO, but powered and STOL! Something you could jump to the friends barbecue with and land in its backyard drink a few bears ponder and back home.

Built in composites, should mean it would be nice shaped and cute, with some nice lines, apart from todays boxy STOL planes. If it is STOL it doesnt need to by ugly does it.

it would be taildragger naturally, with the option for tricycle and FLOATS!

So, would you like to possess and fly one? What would you like more for that (hypothetical) plane to has and to be like?
Yes, if the price is right.

A possible feasible solution might be to have the wing with prestressed CF spars/tubes like the hang gliders version of a Horten/Kasper/Klingberg/Mitchel wing and a synthetic cloth around the construction. This might reduce weight and cost of the aircraft, and have a small boat like underneath powered by an electric mtoor and batteries. Thus it could take off and land electrically yet soar as a glider when catching the right thermals.

What would be the estimated cost and time of such an aircraft?

#### bmcj

##### Well-Known Member
HBA Supporter
Imagine a small, very light, single seat all carbon fiber pusher STOL. It should be open cockpit (wind in the hair), with flight feeling similar to this shown in this VIDEO, but powered and STOL! Something you could jump to the friends barbecue with and land in its backyard drink a few bears ponder and back home.

Built in composites, should mean it would be nice shaped and cute, with some nice lines, apart from todays boxy STOL planes. If it is STOL it doesnt need to by ugly does it.

it would be taildragger naturally, with the option for tricycle and FLOATS!

So, would you like to possess and fly one? What would you like more for that (hypothetical) plane to has and to be like?
ALMOST sounds like you are talking about the FlyNano.

#### Tiger Tim

##### Well-Known Member
Kind of sounds like a gyro would fit the bill. Is anyone marketing those for backcountry fun? I wonder if you could find a place on one to carry spare rotor blades, just in case.

With a set of big tires, squishy long-stroke oleos, and a jump takeoff capability I think one could take over the airplane part of YouTube.

#### Birdman100

##### Well-Known Member
What would be the estimated cost and time of such an aircraft?
this is roughly for now:

structure:

20-24m2 wet surface in all (wing+fuselage, tail feathers); sandwich skin, outer carbon, core airex 3 and 5mm (still thinking about Nomex HC), inner glass.

-carbon: ~ 2000 eur
-glass: ~200 eur
-"aero" epoxy: ~ 500 eur
-foam: ~ 600 eur
-PU varnish (surface finish): ~100g/m2 --> 2-3kg --> 150 eur
other: structural glue; Oratex for ailerons, flaps, elevator and rudder; etc.. additional 500 eur.
--------------------------------
SUM: 4000 eur (roughly)
landing gear

-main lending gear tires: Aero Tundra (buffed smooth): 2 x 170$= 340$
-MATCO wheel+brake: 2 x 285$= 570$ (think I would find something lighter and cheaper!)
-shock absorbers (main): 2 x 250 $= 500$ (this is new, there are cheaper from ebay)
-shock absorber (tail wheel): 150 $other: +20%... -------------------------------- SUM: 1900$ (it must be lower!)
engine

-BLACK BULL electric start: 3340$+ shipping... -Battery: 80$
-Prop (carbon, 3 blades): 400$(i could use wooden one for prototype - 150-200$)
other: fuel line, throttle, etc... 150$--------------------------------- SUM: 4000$
instruments

- Flytec 400 $-airspeed sensor: 140$

molds

EP+glass or Vinilester+glass, gelcoat, steel tubes, etc... rough guess 2000 eur

master patterns

really depends... if CNC the cost would be high.. if hand made (with serbian labour), well 1000-2000 eur in cheap foam, skinned in two layers of glass, smoothed with putty and painted.

vacuum materials

-peel ply, perforated foil, vacuum film (bag), vac sealing tape, absorbers, hoses and so on... 200-300 eur

disposables

-solvents, brushes, rollers, gloves, tools... 200 eur

labour

2000 man-hours for tooling (hand-made master patterns and molds) and additional 2000-3000 for aircraft structure and parts. I would probbably do 1/3 of that myself, so the rest (3000 m-h) would be done by fellow-worker at some 1-2eur/h, so .... 4500 eur is ok. Yes, that is miserable payment but in this case a good side of living in Serbia. You can find a relatively skilled person that would do a bunch of work for 300 eur per month!

OK, lets summarize. I believe I could make this plane and all the tooling for under 20 000 eur, and that would be cost of prototype. It is possible to go down however, by going with cheaper materials (more glass less carbon), cheaper components and so on, so I guess I could end with 15000 eur prototype including molds. But lets stick to initial idea: all carbon STOL - so 20k

for any kind of low serial production costs can be lower much, because of optimizing the production methods, better cost of wholesale materials, lower relative costs of tools and so on...

Note that primary goal is not to produce simple and the cheapest ultralight available, but small, sexy, robust, fun-to-fly and nice-to-look-at modern, carbon STOL!

I think, however, that the cost can be in range of other "not so exotic" FAR 103 ultralights.

#### berridos

##### Well-Known Member
I calculated a precise budget of the molds in vinylester for a similar project and the cheapest option runs for 9000 euros all in.
You hardly will get them for 2000 euros as you proposed. In fact those 9000 euros are currently the next hurdle for my project.

#### Birdman100

##### Well-Known Member
With good organization, all technical and other paper work done and with one full-time worker and another part-time additional worker, I could built a prototype in one year - from zero to ready to fly!

But to finish all the paper work first (though there is no much paper there, 90% computer files - Creo, Auto Cad, Excel (and Excel again, ..and Excel again.. I simply worship Excel!), Mathematica, XFLR, and so on...) I will need at least one year or more!

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#### Birdman100

##### Well-Known Member
I calculated a precise budget of the molds in vinylester for a similar project and the cheapest option runs for 9000 euros all in.
You hardly will get them for 2000 euros as you proposed. In fact those 9000 euros are currently the next hurdle for my project.
what is the area of your molds in m2 - all together?

#### berridos

##### Well-Known Member
40.5m2 + 15cm flanges. Ok, my molds are much bigger

#### Birdman100

##### Well-Known Member
well, thats it. Flanges add 20, sometimes more % on area, so your molds are roughly 50 m2 of laminate.

my molds are 20 m2; I have rectangular wing so I can use one half span mold (actually one for upper one for lower skin) for both wing panels.

I can build mold laminate in 50-60 eur/m2 and that in epoxy!

mold laminate structure (preliminary):

-polyester gelcoat 600 g/m2 --> 3 e/m2
-first layer: 225 gsm glass mat --> 1 e/m2
-3 x 450 gsm glass mat --> 4.5 e/m2
-resin: ~4.5kg/m2 ---> 45 e/m2
--------------
SUM: 53.5 eur/m2

that is 4 mm laminate and is sufficient for this size molds. Proven.

So, mold structure is 20 m2 x 53.5 eur/m2 ="rounded"= 1100 eur

I need about 10-15 kg of steel structure per running meter of mold, so that is additional 200 kg of steel tubes for my molds, so = 150 eur.

Well, I think 2000 eur for my molds are perfectly realistic, in fact it can be even lower if I really want to spare, not to mention that I could even consider polyester (I am not building a laminar wing...)

#### DangerZone

##### Well-Known Member
HBA Supporter
ALMOST sounds like you are talking about the FlyNano.
The FlyNano has a serious design flaw for an amphibian and it is so sad that people invested so much into such a great idea to have such a trivial mistake ruin the project. Have they done any progress lately? It would really be great if they would succeed in making cheap ultralight amphibians...

#### DangerZone

##### Well-Known Member
HBA Supporter
With good organization, all technical and other paper work done and with one full-time worker and another part-time additional worker, I could built a prototype in one year - from zero to ready to fly!

But to finish all the paper work first (though there is no much paper there, 90% computer files - Creo, Auto Cad, Excel (and Excel again, ..and Excel again.. I simply worship Excel!), Mathematica, XFLR, and so on...) I will need at least one year or more!
I forgot in which homebuilder books it was written (was it Raymer, Bingelis, Rutan, Lambie or Stinton, can't remember) but the general rule is that you multiply by three all the initially calculated time and budget. It is quite often that even plans built aircraft declare something like 500 hours which usually results in 1500 hours.

#### Birdman100

##### Well-Known Member
FlyNano is far from what I have in mind; it is NOT a classic configuration airplane, it is NOT a pusher, it is NOT a stol, and it operates from water only.

All I can see FlyNano would share with my STOL is carbon structure and some orange paint that I like how appears at carbon surface.

#### Birdman100

##### Well-Known Member
I forgot in which homebuilder books it was written (was it Raymer, Bingelis, Rutan, Lambie or Stinton, can't remember) but the general rule is that you multiply by three all the initially calculated time and budget. It is quite often that even plans built aircraft declare something like 500 hours which usually results in 1500 hours.
Yep, Im afraid and aware of that. But I cant think like that at the beginning cause I will never start building then. I will not have 3 x 20000= 60000 euros and 3+ years to spent on that anytime soon! Im more in a way to calculate everything as accurate as possible and to add some 20-30% "safety".

frankly, I m developing this idea for years (probably 10 or more), and I will give myself year or more of hardcore work for final project - that sad I dont expect to scale time and costs by as much as three times.

#### bmcj

##### Well-Known Member
HBA Supporter
FlyNano is far from what I have in mind; it is NOT a classic configuration airplane, it is NOT a pusher, it is NOT a stol, and it operates from water only.

All I can see FlyNano would share with my STOL is carbon structure and some orange paint that I like how appears at carbon surface.
Though the real one had issues, I thought the concept MIGHT meet many of your criteria:

YES *small
YES *very light
YES *single seat
YES *all carbon fiber
YES *open cockpit (wind in the hair)
YES *visibility: exceptional

MAYBE *ultralight category
MAYBE *empty weight - less than 90kg (<198 lb)
MAYBE *MTOW - 200kg
MAYBE *instruments: only basic engine (temp) + Flytec
MAYBE *stall speed: 40kmh
MAYBE *cruise speed 70-80
MAYBE *Vne 150

NO *engine: two-stroke PPG 35 HP - in pusher configuration.
NO *landing gear: very robust - "Highlander" type

*** MAYBE means that I'm not sure, but it might be possible.

#### Birdman100

##### Well-Known Member
Ok, sorry maybe I was too rigid, in fact Flynano meets some of my criteria as you showed. But the concept is still different from what I have in mind - an ultralight capable of backyard and some serious "off-road" flying.

I agree that FlyNano is an interesting design, with or without issues (am not informed about that).

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