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blane.c

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OK -- i Get-It now ; sorry it my last post , was a bit abrasive !!

The Schweizer SGS 2-33 has a dirty fuselage, with struts , and
still gets a glide of 22 : 1 ; so why couldn't a single-place ultralight
be designed around those parameters , to achieve near the same
performance ?

Bille
I am curious in that a Schweizer is "dirty" by glider standards if it on the other hand is "clean" by ultra-light standards? Will it achieve in level flight more than 55mph?
 

kubark42

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I am curious in that a Schweizer is "dirty" by glider standards if it on the other hand is "clean" by ultra-light standards? Will it achieve in level flight more than 55mph?
I'm not sure I fully understand that question. A glider stalls in level flight in still air. So to keep any speed at all requires some kind of dive. However, the published best glide speed is ~45kn, and that's about 15kts over its stall speed so if you put a motor on it and flew it at 55kts... well, let's just say you'd be wasting a ton of energy without much advantage.

I would say the 2-33 is clean by ULM standards. It's surprising how much drag all of the open cabling, wires, fuel hoses, etc cause. On my AC-5M, extending the engine pod doubles the sink rate. Check out a picture with engine deployed and marvel that the little engine and propeller is the same drag as the rest of the airplane.

As an aside, the already aged 2-33 is based on an antique design from the 1940s, and it's a bit of an embarrassment that we're stuck still using it in the US.
 

blane.c

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I'm not sure I fully understand that question. A glider stalls in level flight in still air. So to keep any speed at all requires some kind of dive. However, the published best glide speed is ~45kn, and that's about 15kts over its stall speed so if you put a motor on it and flew it at 55kts... well, let's just say you'd be wasting a ton of energy without much advantage.

I would say the 2-33 is clean by ULM standards. It's surprising how much drag all of the open cabling, wires, fuel hoses, etc cause. On my AC-5M, extending the engine pod doubles the sink rate. Check out a picture with engine deployed and marvel that the little engine and propeller is the same drag as the rest of the airplane.

As an aside, the already aged 2-33 is based on an antique design from the 1940s, and it's a bit of an embarrassment that we're stuck still using it in the US.
If you built a part 103 craft based on the 2-33 and you worked the ultralight formula sheet would it be to clean a design to meet the 55mph speed limit of the regulations?
 

kubark42

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If you built a part 103 craft based on the 2-33 and you worked the ultralight formula sheet would it be to clean a design to meet the 55mph speed limit of the regulations?
The 2-33 is a two seat glider with an empty weight of 600lbs and an official stall speed of 31kts. From pretty much every perspective it's really far from ULMs limited to single-seat and 155lbs.

I think the best bet for ULM eSoaring conversion is taking a 155lb ULM glider and putting in a propulsion system. Grab a Sparrowhawk and lop off its nose for an FES-style system?

Strange aside, but I wonder if a self-launching UL glider is considered "powered"? The reason I ask is because the 24kts stall speed limitation is only for powered ULMs. That's hard in a glider with a reasonable wing-loading.

P.S. Part 103's level-flight max speed limitation is 55kts, which is closer to 63mph.
 

Bille Floyd

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...

P.S. Part 103's level-flight max speed limitation is 55kts, which is closer to 63mph.
And that 55kts, is really close to the VNE for my glider , at max
weight ; this is gonna work out just fine !! :)

After i finish paying for my glider, (in several more months) ; i might
contact you for help , if the offer is still open ?

Bille
 

BJC

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As an aside, the already aged 2-33 is based on an antique design from the 1940s, and it's a bit of an embarrassment that we're stuck still using it in the US.
No one is stuck; there are alternatives. The 2-33 still is being used because it is cost effective for the current batch of glider-pilots-in-training.


BJC
 

Speedboat100

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Speaking of Atos, they do have something in the works, the Atos Wing:


And then there's Birdy:

Those both seem like winning approaches, so long as they can keep costs down enough to satisfy the market.

New model: AtosWing | Peoplecanfly
 

Victor Bravo

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The 2-33 works, is safe, and is cheaper than other options. If Schweizer put the 2-33 back into production, I believe the cost of a NEW one would still be less than a NEW production AS-K21 or Grob 103 or equivalent composite trainer. The undeniable fact that the 2-33 is based on a 1940's design is irrelevant if it meets the need. The Blanik is a 1950's design and makes an excellent trainer, slightly more modern than the Schweizer product and slightly better performance. The new Blanik at 72,000 Euro I believe is less expensive than the 100-120K Euro plastic gliders, is it not?

The wheel is not exactly new and is still very relevant today.
 

opcod

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I did see a 2-33 drop right at the flight line table, in order to not go walking it back. But the drop stall was about at 25ft high. Wing flex and jump / touch the ground 2 times, but tire was ok and we just continue right as nothing happen. true tank. Altho.. 21:1 and not 22.
 

Bille Floyd

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If you built a part 103 craft based on the 2-33 and you worked the ultralight formula sheet would it be to clean a design to meet the 55mph speed limit of the regulations?
This is a question :
If the airframe can indeed exceed the 103 speed limit, but the
prop is pitched so the aircraft can Not exceed the speed limit ; is
it 103 legal ?

And on the 2-33 :
I wasn't trying to belittle that glider, in any way ! By sailplane standards
it is dirty, (and by Ultralight standards, it's clean) ; but it totally fulfills its
intended mission, as a glider meant
to teach students. The 2-33 ls built like a Tank, and can take a lot
of abuse ; it flies really well, for how stable it is. I've actually would
that thing up, in the core of a 1500-f/min thermal, at a really high
bank angle before ; and it had absolutely no tendency to enter a spin
or have a tip-stall. Great glider ; for what it was designed to do !!!

@ kubark42 :
Really Like your AC-5M !!!! 👍


Bille
 

David Lewis

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Longwood FL
As an aside, the already aged 2-33 is based on an antique design from the 1940s,
Don't disagree, but with one aboard the 2-33 is a delightful glider. Not the most nimble aircraft but very pleasant to fly and surprisingly viable in light air if you don't weigh too much and have the fabric (Hindenburg) nose.
 

BoKu

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Don't disagree, but with one aboard the 2-33 is a delightful glider. Not the most nimble aircraft but very pleasant to fly and surprisingly viable in light air if you don't weigh too much and have the fabric (Hindenburg) nose.
All 2-33s have fiberglass nose. The 2-22 have the Hindenberg nose.
 

Victor Bravo

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I wonder how much the glass nose cone weighs on the 2-33. Is it made well, or did Schweizer have the local swimming pool slide and diving board shop hit it with a polyester chopper gun?
 
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kubark42

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A lot of quotes about the 2-33...
I sort of started something here that is a distraction from the topic at hand. The relative merits and demerits of the 2-33 are probably best discussed on RAS (although considering how much better the quality of conversation is here I certainly see the attraction of not going there).

I don't mean to denigrate the 2-33 as a plane, all planes are equally beautiful in my eyes. My comment stems from how, elsewhere in the world, glider clubs use trainers which are more appropriate to modern flight, but US clubs find themselves unable to keep pace. The exact hows and whys are a philosophical question and probably again belong on RAS.

Coming back to eSoaring, I'm looking at the ATOS Wing, and I think it's the closest thing to home buildable. The wing structure is not something I've seen before, where the covering seems to be a rigid sail cloth of some kind, like you'd find in a wind-surfing board. But it's really easy to source that kind of material, and it's not inordinately pricey for the surface needed.

What isn't great about the ATOS Wing is the seating position. It puts the pilot above and behind the wing, blocking all visibility. This might be to fit the tall landing gear and keep battery cables short, but that seems sub-optimal.

So if I were considering a home-build version, I'd think about how to build that style wing with a Birdy pusher tail, so that the human and the battery would be reversed.
 
Last edited:

BoKu

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I wonder how much the glass nose cone weighs on the 2-33. Is it made well, or did Schweizer have the local swimming pool slide and diving board shop hit it with a polyester chopper gun?
I don't really recall; it's been a long time since I've seen the inside of one. At a guess, it was probably about half way between a Libelle and a shower stall.
 

IVAN99m

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Jun 10, 2020
Messages
7
This is a question :
If the airframe can indeed exceed the 103 speed limit, but the
prop is pitched so the aircraft can Not exceed the speed limit ; is
it 103 legal ?

And on the 2-33 :
I wasn't trying to belittle that glider, in any way ! By sailplane standards
it is dirty, (and by Ultralight standards, it's clean) ; but it totally fulfills its
intended mission, as a glider meant
to teach students. The 2-33 ls built like a Tank, and can take a lot
of abuse ; it flies really well, for how stable it is. I've actually would
that thing up, in the core of a 1500-f/min thermal, at a really high
bank angle before ; and it had absolutely no tendency to enter a spin
or have a tip-stall. Great glider ; for what it was designed to do !!!

@ kubark42 :
Really Like your AC-5M !!!! 👍


Bille
Hi.
I am trying to build a motor glider and looking for an Engine .
What is the price for an Electric engine?
 

kubark42

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Joined
Oct 19, 2020
Messages
65
Hi.
I am trying to build a motor glider and looking for an Engine .
What is the price for an Electric engine?
Most famous answer in engineering: it depends.

It all comes down to size and precision. You can get 10kW motors for $300, if you're happy with R/C grade components. On the flip side, you could get a 30kW Emrax or Rotex (not Rotax!) for thousands.

The motor controller is also important, and has to match the motor. Typically, the motor controller is more expensive than the motor.

What size motorglider are you looking to build and what's the mission? Is it a self-launching sailplane or is it a cruising motorglider?
 
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