DIY electric manned ultralight (with cute puppy)

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I'm more worried about the lack of any shock absorbtion on the direct mounting to the spar/wing relying on perfect landings not to damage anything...he says if he tweaks it will be done.....
 
Flyfalcons: I don't design real planes, just boostglide and a couple LB electric ones.

I am certain I know more than Peter. Like laminar flow, the many different kinds of drag, basic aerodynamics and structural strength, Reynolds #. I think he just has a cartoon image of what a successful plane looks like, and he is trying to duplicate that, one way to get in real trouble.

For example, notice that he is just fiberglassing the OUTSIDE of the foam parts. Would be better to cover both sides.

His landing gear needs a suspension, springs and shocks. You cannot tell that wing looks right. Do you think he is doing ANY calculations like wing loading, drag total, power rqrd for a certain speed?

If I had any BitCoins, I would make a bet that it won't work. Like I said, he should fly it RC first!

crash.jpg
 
I don't see any comment about instruments, airspeed etc, calculation of stall speed, he mentions doing loops etc after doing a full load testing, but I think a sane person wouldn't even try to do something like that.

Frank
 
Oh no, he started the wing. I don't like it. Chord too small, way too thick. Is he going to stick aluminum tubes in those giant holes? Or just flimsy wood spars? Back to the drawing board, after some college, dude.

Take some classes on comprehension for yourself.

It's for a BIPLANE. He said so in that very video, as well as earlier.

And yes, thick wings are GOOD for high lift at low speed.

You're pot-shotting at everything he's doing, as though you are an expert on making a small ultralight. You don't even listen to (or else understand) what he's telling you (Biplane).

The biggest "tell" is your claim that the wing is way too thick. Not for an aircraft like this.

The image below is from: https://www.zenithair.com/kit-data/ht-87-6.html

ht-876a.gif


And take a look at the deep camber airfoil on this list:

main-qimg-4e6dbe95378d0acc92f3d0a7b441dd73


The NACA 2421 may be even thicker than what he is using.

main-qimg-bacb001f81d88ab627461b903efe2927


Now, I routinely fly a R/C plane with a pretty thick airfoil like that, the Parkzone Radian 2 meter electric sailplane. Members on RC Groups have deduced the airfoil seems closest to the Gottengin 398 airfoil (Photo of Radian airfoil below with Gottengin outline). The Radian has superb flying characteristics, the airfoil "hangs in there" and does not stall easily (any conventional plane will stall of course, but some airfoils are nasty and looking for any excuse to tip stall, others way gentle). And at that, the Radian's trailing edge is "chopped" short, about 1/4" thick rather than tapering to a point (see photo). They have it chopped short since if it was tapered thin, the TE of that foam wing would be damaged very easily in transport, or "hangar rash".

gdK4S1v.jpg


I have concerns about Peter doing this. But I would have similar concerns about anyone building their first ultralight.
 
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Take a look at the 3 videos I posted of real electric planes, the best being the Pipistrel. Do their wings look anything like his? Gee, none are biplanes. Why do you think that is? BECAUSE THEY ARE OBSOLETE. Who needs all the struts and bracing wires. WAY DRAGGY.

The fat airfoil is very draggy, and unnecessary. Actually, for lift you don't even need an airfoil. I have seen model planes made of flat foam, the wings still generate lift. Why?

Because what they teach in school about there being a "low pressure area" on top of the wing that generates lift

IS WRONG.

Sure, there may be a low pressure zone, and airfoils help airflow and do improve lift, the FACT is that most of the lift is just from Newtons 3rd law. It is ANGLE OF ATTACK and the impingment of air on the tilted wing generating a lift vector.
Proof of this is the use of FLAPS on wings, what do you think that huge down angle does?????

I worked with Jerry Gregorek, aero prof at OSU, and another one at Penn State in the early days, learning practical skills
of aircraft construction. Something Peter is missing out on is PHYSICS. He will find as he winds up falling thru the sky at 32 feet per second per second that making a human carrying plane out of wood, foam, fiberglass, drawn on the back of a napkin, can be suicidal. He would be a lot smarter to at least make a wind tunnel, to test it, like the boys in Dayton did!
If you are so thrilled with Pete's project, why don't you contact him and offer some CAD documentation assistance. Then go on to Finite Element Analysis, and Computational Fluid Dynamics.

:roll:

wright.jpgwind tunnel.jpg
 
Well, I looked at some biplane airfoils, and you are right, most are thick and small chord. But this tri-plane wings are thin:
tri-plane.jpg

Here is an article on what I was talking about:

https://warp.povusers.org/grrr/airfoilmyth.html

Note that stunt planes have symmetrical airfoils, and fly fine. Even a plane with a Clark-Y airfoil can fly upside down

I wish Peter the best of luck. But hope he respects Murphys law. I think he really needs some help. Like a mentor.

Any volunteers?
 
I think he really needs some help. Like a mentor.

Any volunteers?

Yeah, looks like you have. You care so much to keep harping about this and claiming you know all about building ultralights. So, you should enlighten him with the awesomeness of your wealth of knowledge about what you have learned about designing and building your ultrallght aircraft that you've flown.

Let me know what he says.

Or, just keep potshotting him here without having the [whatever] to contact him directly and in detail as you have done here. I have a pretty good idea which of the two you'll choose to do (or not do).

BTW - seems in a previous video he referred to having the equivalent of a mentor, checking over what he's doing. I may be wrong in that, no going to waste my time reviewing to be sure. But at least I paid enough attention to his videos to know he was building a biplane, which you totally missed in your "thorough reviews" of what he's doing.

- George Gassaway
 
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At least this guy followed proper engineering principles! Did the necessary calculations to ensure safe flight. Not trivial.

Can't remember his name, but liked the movie.

[video=youtube;IANwb_qT1gg]https://www.youtube.com/watch?v=IANwb_qT1gg[/video]

plane.jpg
 
He's mentioned in passing on several occassions stealing construction specifics from other very popular and tested homebuilt aircraft designs and is even doing things like using stronger hardware than they do (heavier gauge metal items, larger diameter bolts, etc.) He's also paying close attention to viewer comments and emails from people who know what they're doing. He now has a Ballistic Recovery System which he got for $1,500. Maiden flight will be live-streamed. Puppy growing rapidly.

[video=youtube;xEqCt7GZo7M]https://www.youtube.com/watch?v=xEqCt7GZo7M[/video]
 
Take a look at the 3 videos I posted of real electric planes, the best being the Pipistrel. Do their wings look anything like his? Gee, none are biplanes. Why do you think that is? BECAUSE THEY ARE OBSOLETE. Who needs all the struts and bracing wires. WAY DRAGGY.

The fat airfoil is very draggy, and unnecessary. Actually, for lift you don't even need an airfoil. I have seen model planes made of flat foam, the wings still generate lift. Why?

Because what they teach in school about there being a "low pressure area" on top of the wing that generates lift

IS WRONG.

Sure, there may be a low pressure zone, and airfoils help airflow and do improve lift, the FACT is that most of the lift is just from Newtons 3rd law. It is ANGLE OF ATTACK and the impingment of air on the tilted wing generating a lift vector.
Proof of this is the use of FLAPS on wings, what do you think that huge down angle does?????

I worked with Jerry Gregorek, aero prof at OSU, and another one at Penn State in the early days, learning practical skills
of aircraft construction. Something Peter is missing out on is PHYSICS. He will find as he winds up falling thru the sky at 32 feet per second per second that making a human carrying plane out of wood, foam, fiberglass, drawn on the back of a napkin, can be suicidal. He would be a lot smarter to at least make a wind tunnel, to test it, like the boys in Dayton did!
If you are so thrilled with Pete's project, why don't you contact him and offer some CAD documentation assistance. Then go on to Finite Element Analysis, and Computational Fluid Dynamics.

:roll:

View attachment 329389View attachment 329390

This tells me all I need to know about your authority on the design and construction of aircraft. I'm sure you are aware, for instance, that federal requirements on ultralight aircraft favor a draggy design (max level speed limit), and that strut bracing allows the wings to be built lighter than if they were full cantilever? Did you notice, in the first video, him flying a scale RC version of his design to validate stability? Did you know that many aircraft designs are built with wood, foam, and fiberglass?
 
He didn't even know (or at least remember) that it was a BIPLANE!

Ignorance of the value of thick wing cross sections for high lift slow flying.

FWIW - some pics I took a week ago at a private air museum. Most of the aircraft were of 1930's vintage a few 40's.

Ford Tri-Motor, still in flyable condition.

A84tp15.jpg


Wings (not in very good shape, metal at bottom, not the wood on top) that apparently were also from an old Ford Tri-Motor. Look at HOW THICK!. The leading edge is closest to the camera, part of the root leading edge gone.

z9BVBsv.jpg


Wing set from an aircraft sort of similar to the type seen in the background (albeit those wings were from a single-engine aircraft). A bit of the trailing edge is funky due to the root attachment's lack of the flap (flaperon?) trailing edge farther out. Again, thick.

bHYdjCu.jpg


And the root of an old aircraft frame. Do not recall if the plan is to rebuild or keep as-is as an example of the structure for some aircraft of the era. Yet again, THICK!

hOJMqjB.jpg



But of course a thin sheet wing with a rectangular cross section would fly better according to XolveJohn. Just give it enough angle of attack? Never mind the FACT that high angle of attack with thin crappy airfoils want to STALL and crash the plane, while THICK properly designed airfoils do not stall nearly as easily?

What the h___ did those old airplane designers know, they didn't have "CFD"?
 
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Yes, George. You have made your point perfectly clear. That you are stuck in the vacuum tube era.

Remember those? How electronics used to run.

THE BIPLANE IS OBSOLETE. Like I said, look again at the 3 real electric plane videos I posted. ALL are monoplanes.

Oh, in case you missed it, the spark gap transmitter, the telegraph, the hydrogen filled airship, are also all DEAD.

And I challenge you to find even ONE commercial plane of ANY type made today with a fat airfoil. A passing fad.

But perhaps one day there may be a biplane jet airliner, but it will look like this: :facepalm:

jet biplane.jpg

And I never said flat wings were the best, just that they are viable, for certain hobby applications, like 3D foamy model planes, a very hot field. There are maybe 10,000 rocketeers in the USA, but 10 million airplane dudes. Dude.

foamy.jpg
 
You do realize the mission requirements of an an ultralight vehicle are different from those of a GA aircraft or transport category aircraft?
 
You guys don't get it. He's NOT building a commercial airliner costing millions of dollars.

He's NOT building an airplane to fly fast and efficiently from Point A to Point B with as little fuel as possible.

It's a "I set out to build my own plane and fly it" project, not a plane to fly a lot, to different places and back.

He's building a limited use Ultralight. He's not planning to fly it very much, possibly not plan to fly it from point A to B, likely just fly it around for a few minutes and land back where he took off from.

His priorities are to fly safely using the techniques he feels he can do, and flying LOW-speed with a thick airfoiled biplane is a GOOD thing for that. There are indeed reasons why biplanes were developed first and Monoplanes came along later. Structurally a Biplane is easier to build STRONG and LIGHT, for the same given amount of wing area.

There's not a Bleeping thing wrong about using good solid proven aerodynamic design for one's own personal aircraft. If you feel so strongly otherwise, then by all means post videos and pictures of the builds of your thin-airfoiled monoplane ultralight aircraft. Oh yes, make yours with a thin SYMMETRICAL airfoil XolveJohn, for the inverted and aerobatic flying you'll do with yours.
 
I think folks need to to simmer down, think there is no problem discussing what he is doing and how. I have general problems with his approach to many of his flite test projects, and a few design points he has gone with here, but I wish him luck. I dont think you have to have built a full-size plane to have opinions, lets keep it civil .
 
[video=youtube;O6sy5bt4D-Y]https://www.youtube.com/watch?v=O6sy5bt4D-Y[/video]

Flew near dark Thursday, twice. Livestream posts:

[video=youtube;XMrbdLfG8dg]https://www.youtube.com/watch?v=XMrbdLfG8dg[/video]

Post-flight review. Some low-res video from the flights (livestream camera looking at laptop screen). They'll post good quality edited videos later, with a better plan for improvements.

[video=youtube;YD8U5eGTcKY]https://www.youtube.com/watch?v=YD8U5eGTcKY[/video]
 
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I wondered what happend to the livestream, I was surprised he actually flew after dark, again it's an attitude thing with this guy. I'm glad it's intact, it's really underpowered, and he needs to address that, and hopefully his gear setup isn't an issue and that when actual aerodynamic loads/gusts etc happen it will hold together.
I'm a bit worried that his cavalier attitude will encourage others to do TLAR aircraft design, whether that is actually what he did, it gives that impression.
and I wish he'd put a helmet on, even a bicycle helmet.

Frank
 
I wondered what happend to the livestream, I was surprised he actually flew after dark, again it's an attitude thing with this guy. I'm glad it's intact, it's really underpowered, and he needs to address that, and hopefully his gear setup isn't an issue and that when actual aerodynamic loads/gusts etc happen it will hold together.
I'm a bit worried that his cavalier attitude will encourage others to do TLAR aircraft design, whether that is actually what he did, it gives that impression.
and I wish he'd put a helmet on, even a bicycle helmet.

Frank
He mentioned in the above video that he removed it because it wasn't good but ALSO because he was unknowingly breaking rules by flying without strobes after dark. I didn't watch the livestream because it was so bad, but he mentions in the day flight video above that he's flying from a private strip. So, although I'm not a pilot, since that unlit, uncontrolled strip MIGHT have (one in a million) been used for an emergency landing by some other plane, even though the kid never flew high enough for other planes to have to worry about seeing him, strobes on his plane would have alerted the plane making the emergency landing that he was on the strip.
 
Yeah, I don't know about he didn't know, when I checked the rules last week, this is in the first couple of paragraphs, I would assume he did read those when trying to conform to the regulations, and I was thinking about that when he did the livestream that I watched....when they said they couldn't see much.....

§ 103.11 Daylight operations.

(a) No person may operate an ultralight vehicle except between the hours of sunrise and sunset. (b) Notwithstanding paragraph (a) of this section, ultralight vehicles may be operated during the twilight periods 30 minutes before official sunrise and 30 minutes after official sunset or, in Alaska, during the period of civil twilight as defined in the Air Almanac, if:

(1) The vehicle is equipped with an operating anticollision light visible for at least 3 statute miles; and
(2) All operations are conducted in uncontrolled airspace.

He mentioned in the above video that he removed it because it wasn't good but ALSO because he was unknowingly breaking rules by flying without strobes after dark. I didn't watch the livestream because it was so bad, but he mentions in the day flight video above that he's flying from a private strip. So, although I'm not a pilot, since that unlit, uncontrolled strip MIGHT have (one in a million) been used for an emergency landing by some other plane, even though the kid never flew high enough for other planes to have to worry about seeing him, strobes on his plane would have alerted the plane making the emergency landing that he was on the strip.
 
Yeah, I don't know about he didn't know, when I checked the rules last week, this is in the first couple of paragraphs, I would assume he did read those when trying to conform to the regulations, and I was thinking about that when he did the livestream that I watched....when they said they couldn't see much...
Yeah, I was thinking that myself because even without knowing the actual rules, I could figure out why having strobes would have been a really good idea. He may have been working by this philosophy - "It's easier to ask forgiveness than it is to get permission." - Rear Admiral Grace Hopper, maybe not the best one when dealing with FAA safety rules. He said something like, "Please don't take my pilot's license" in the day flight video. Plus, one wouldn't think he'd put something on YouTube and then later delete it if he knew he was doing something wrong at the time.
 
Yeah, it's a maturity and mindset of his approach that gets to me. If he had just said, yeah I got go fever, we've all been there, but if he is building something to a spec that he has to meet legally then he should have read the spec. On the powerplant side, I don't think he knows how much thrust his motors are delivering, or even calculated or have a swag on how much is required for flight. He was underpropped and just had a guy holding the plane in the basement to do a TLAR approach to enough power. It's just really a bad example, even if the end result happens to work or not. I mean I'm enjoying watching it as much as the next person, but I really hope I don't read about some kid killing himself trying to replicate it. People put illegal stupid crap on youtube all the time btw.:)

Yeah, I was thinking that myself because even without knowing the actual rules, I could figure out why having strobes would have been a really good idea. He may have been working by this philosophy - "It's easier to ask forgiveness than it is to get permission." - Rear Admiral Grace Hopper, maybe not the best one when dealing with FAA safety rules. He said something like, "Please don't take my pilot's license" in the day flight video. Plus, one wouldn't think he'd put something on YouTube and then later delete it if he knew he was doing something wrong at the time.
 
Yeah, it's a maturity and mindset of his approach that gets to me. If he had just said, yeah I got go fever, we've all been there, but if he is building something to a spec that he has to meet legally then he should have read the spec. On the powerplant side, I don't think he knows how much thrust his motors are delivering, or even calculated or have a swag on how much is required for flight. He was underpropped and just had a guy holding the plane in the basement to do a TLAR approach to enough power. It's just really a bad example, even if the end result happens to work or not. I mean I'm enjoying watching it as much as the next person, but I really hope I don't read about some kid killing himself trying to replicate it. People put illegal stupid crap on youtube all the time btw.:)
He mentioned he was under-propped for those motors, but I missed it if he's changed them yet. Has he? Also, he's under the best voltage for the motors, too, but he says he has the batteries on order. Those two improvements might give him significantly more thrust. Something that has made me cringe since day one has been the stubby landing gear supports with ZERO shock absorption.
 
The day he did those two first flights at dark, it was NOT PLANNED to be flying that late in the day.

He made a reference (IIRC in the deleted livestream) to having had issues thru that day causing delays, it had been intended to fly hours earlier. Then the weather would be crap for the next few days after that, so it was either fly near dark or days later.

There's too much Monday-morning quarterbacking on this. I note that NOBODY said a word about FAA rules about flying after dark, until he himself mentioned it in the newest video. I posted those livestreams in this thread LAST WEEK. And not ONE of you said anything about FAA regs after sunset. So it didn't cross your minds either, only now as an issue to pound the guy over.

Funny nobody said "Gee I was wrong, IT FLIES", either.

Pretty much expected that, though.

Everybody else is an expert on this, except for the fact they've never done anything like this themselves.

Yeah "vacuum tube era" aerodynamics do work after all, who woulda thunk it?

Now, If I built an electric manned aircraft to fly in, would I use that design? No. Because it looks nothing like a 50% scale Lunar Module Quadcopter. :)
 
George you are way off base here and I think your attitude is confrontational when it doesn't need to be especially toward me. In fact I did think about him flying after dark, when I was watching it live but I did not post a comment on that here, I posted a comment when he brought it up about not knowing. When I read the requirements last week when looking for weight limits I noticed the daylight restriction and noted he was flying after dark.

I never said it would not fly, and I don't owe anyone an apology. I said I don't like his cavalier TLAR attitude and think it sets a wrong example. I find some faults in some of the choices he has made and in his lack of diligence in doing what I consider life saving required calculations. He should have known the rules and running late does not excuse it. Getting in a hurry because of weather or time is exactly the wrong reason to fly an airplane and sets a bad example. I'm surprised that someone like you who normally is very aware of the rules and I assume are strict to follow them thinks this is ok. I also am surprised that you think that some of his approaches are just fine and dandy just becuse it happened to work. AND I know you ride a bike, I'm surprised you don't even have a problem with him not wearing even a bicycle helmet in case of a crash...

I think there is nothing wrong with evaluating someones approach to a problem and pointing out areas that I think are not thought out fully, it's how we all learn and I think it's valid to point these things out to get people to think about what they do and how they approach a problem and not just mindlessly think the guy and his approach are absolutely wonderful. This is a perfect learning oportunity to apply to rockets, conditions are not good and it's underpowered, take a step back and don't fly. Another example is his javelin rocket launcher, launching out of a tube next to his face, I don't think this guy is a good example for my kids.

It still remains if the plane can be airworthy and sustain flight over a long enough time and during normal altitudes and load conditions for him to stay alive.


Frank
 
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