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Old Nov 16, 2011, 03:09 AM
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"Sbach 342" upgrade for 3D.

"Sbach 342 UMX" very good airplane, but for 3D is too heavy (about 70 grams with battery) and have too high a speed.
Due to excessive weight aircraft no can fly in small enclosed spaces and is easily broken during landing.

This theme is designed to address these shortcomings.
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Last edited by Vladimir88; Nov 16, 2011 at 05:29 AM.
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Old Nov 16, 2011, 03:10 AM
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Joined Mar 2010
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The first version of the upgrade "Sbach 342" to 3D.

Parts list:
1) The gearbox - "HP03TR8(5,3:1)G" (weight- 4 g.)
2) Prop - 160 x 70 mm ("Su-26m") (1,5 g.) http://www.horizonhobby.com/Products...ProdID=PKZ3502
2) ESC - "TMM-0703-3 EXPERT" (1,1 g.) http://mgm-compro.com/index.php?tid=...-0703-3-expert
3) Reciever - "Rx 32" (0,28 g.) http://www.deltang.co.uk/
4) Servo - "HK1300" (1,1 g. x 4= 4,4 g.) http://www.hobbyking.com/hobbyking/s...ar_Servo_.html
5) Battery - 1S, 160 mhA (4,2 g.)
6) Wires - #38 http://www.microflierradio.com/Miscellaneous.html

Specification my design gearbox "HP03TR(5,3:1)G":
Thrust- 72 g. (for - 3,5 V; 2,9 A; prop 160x70mm).

1) The closest analog - the motor "MM13/3/12T" - http://www.microbrushless.com/productsG1.htm .
This motor has similar specification and have weight about 5 gram.

2) Very good option is to use a motor "MM- 13/4/8T"- http://www.rcgroups.com/forums/showt...ght=mm+13+4+8t
"MM- 13/4/8T" have weight about 6 gram and thrust- 80 g (for - 3,5 V; 3,3 A; prop 160x70mm).
But for this motor to must use the battery 1S, 240 mhA(25C) with weight 7 g. and the final weight of "Sbach 342" will about 45 grams.

3) Velocity model can be performed on the motor - "G15 12W 3.6V Bronco" (7 g.) http://www.gasparin.cz/page.php?page...&lng=en#bronco
In this case, the weight will about 47 grams, and the ratio of thrust to weight ratio is about 2.



For maximum weight loss had to give up the wheels, some plastic parts and all electrical connections made by soldering.
Cut holes in the foam for slightly reduced weight- about 1 gram.
Tool for making holes in the foam- http://www.foamwerks.com/tools/holedrill/

Description of contacts for battery- http://forum.rcdesign.ru/f80/thread1...ml#post2499713

Plate for gearbox made of composite material - two sheets of balsa (1,5 mm) and three sheets of fiberglass(0,25 mm) by sticking flat layers.
Plate can be made from only carbon or fiberglass, but the thickness of these materials will be small (0,5...1 mm) and therefore it will worse to stay in the foam.


The final weight of "Sbach 342" turned out about 41 grams(with battery 160 mhA,1S) instead of 70 grams!

The first test flights have shown sufficient draft and efficient management of the servo.
The difference in weight turned is very palpable.
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Last edited by Vladimir88; Nov 21, 2011 at 01:52 AM.
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Old Nov 16, 2011, 07:07 AM
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Tabriz, Iran
Joined Sep 2008
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WOW! I can't believe it lost 29grams! how much thrust does the GB produce?

SS

EDIT: oh, nevermind. That's an awesome thrust to weight ratio you've got there!
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Old Nov 16, 2011, 09:34 AM
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Quote:
Originally Posted by starscream4002 View Post
WOW! I can't believe it lost 29grams!...
Or nearly twice (1,7) weight less!

My opinion is that the "E-Flite" too much attention to the idea of ​​solving the problem deficit of thrust using increasing the supply voltage to 2S.
As a result of recent models of "UMX Beast 3D" and "UMX Sbach 342" have too much weight and small propellers.
Micro aircraft must be able to fly slowly (with the exception of EDF), and for this they must have low weight and for the 3D must have large propeller.
I understand them, really develop a new gearbox with brushless motor more complex than simply increasing the supply voltage.

Quote:
Originally Posted by starscream4002 View Post
...how much thrust does the GB produce?...
EDIT: oh, nevermind. That's an awesome thrust to weight ratio you've got there!
In the description I have given thrust gearbox - 72 grams.
The ratio of thrust to weight by the aircraft is obtained is about- 1,8.
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Last edited by Vladimir88; Nov 16, 2011 at 10:04 AM.
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Old Nov 16, 2011, 10:43 AM
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USA, MI, Lansing
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bottom line, E Flite generly sucks! have tried many of there planes and they all have stuff wrong with them. i stick to independt guys making stuff in there garage.
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Old Nov 16, 2011, 11:06 AM
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Forney, TX
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Quote:
Originally Posted by Vladimir88 View Post
"Sbach 342 UMX" very good airplane, but for 3D is too heavy (about 70 grams with battery) and have too high a speed.
Due to excessive weight aircraft no can fly in small enclosed spaces and is easily broken during landing.
The Sbach was not designed for 3D flying, it is more of a pattern flyer. It is also not intended for indoor flying (unless it's a large venue). Also keep in mind that E Flite planes are designed for the masses, so they're built sturdy for crash-resistance. Swiss-cheesing the airframe is certainly a way to save weight for those that don't mind weakening the airframe.

Quote:
Originally Posted by Vladimir88 View Post
As a result of recent models of "UMX Beast 3D" and "UMX Sbach 342" have too much weight and small propellers.
I disagree regarding the weight, but agree on the props not being optimal. That's easy to change though since GWS props bolt right on.

Quote:
Originally Posted by Vladimir88 View Post
Micro aircraft must be able to fly slowly
There are plenty of slow micro aircraft out there, I like the Beast/ Sbach/ Stryker specifically because they are fast and can be flown outdoors in moderate wind with no trouble. More power to you for trying to mod your Sbach into something it wasn't intended for, but implying that it is a poor design is just plain wrong. It is perfect for what it is- a zippy small-area pattern plane.
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Old Nov 16, 2011, 11:24 AM
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East Bethel, MN USA
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Vladimir,

I echo Tres Wright's sentiments regarding the original design. The Sbach was never intended to be a slow-flier or a 3D plane. It was specifically designed for speed and precision aerobatics, and it does both very well.

That said, I am also a modder (I've hopped-up nearly every car I've owned - even my daily-drivers), so I appreciate the efforts of others who also enjoy making products do things that the manufacturer never intended.

For a reference, here's some data from my stock Sbach w/5030 prop & homebrew Hyp 180 2s pack:

Static RPM ------ 10,860
Thrust ---------- 115g
AUW ------------ 65.4g
Thrust:weight --- 1.75:1
Wing loading ---- 5.7 oz/sq. ft.

Your setup:

Thrust ----------- 72g
AUW ------------- 45g
Thrust:weight ---- 1.6:1
Wing loading ----- 3.9 oz/sq. ft.

Going by the numbers, you reduced wing-loading by a whopping 32%, yet you maintained the thrust-to-weight of the stock plane with the highest-performing prop/battery combo.

Great work!

Joel
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Last edited by turboparker; Nov 16, 2011 at 11:33 AM.
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Old Nov 16, 2011, 01:25 PM
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Quote:
Originally Posted by turboparker View Post
...

Static RPM ------ 10,860
Thrust ---------- 115g
AUW ------------ 65.4g
Thrust:weight --- 1.75:1
Wing loading ---- 5.7 oz/sq. ft.

Your setup:

Thrust ----------- 72g
AUW ------------- 45g
Thrust: ---- 1.6:1
Wing loading ----- 3.9 oz/sq. ft.

Going by the numbers, you reduced wing-loading by a whopping 32%, yet you maintained the thrust-to-weight of the stock plane with the highest-performing prop/battery combo.
Joel ,thank you.

But you have the error:
In my setup AUW= 41 g(but not 45g).
Therefore, the in my Thrust:weight = 1,75 (but not 1,6).
Respectively my Wing loading = 3,5 oz/sq. ft.(but not 3,9)
Respectively reduced wing-loading - about 1,6 times(!!!) =5,7: 3,5 (but not 32 %).
(Or, this can calculate in another way- reduced wing-loading about = reduced weight (for the same wing area)= 65,4g: 41g = 1,6 !)
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Last edited by Vladimir88; Nov 16, 2011 at 03:03 PM.
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Old Nov 16, 2011, 01:38 PM
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That still doesn't change anything turbo said. It's still the same thrust to weight.

Why remove the landing gear though?
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Old Nov 16, 2011, 01:57 PM
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Wow great work Vlad.

Very impressive that you reduced the weight so much.

What about working up a gear box for a 2s motor? I bet you could get greater than 2:1 thrust ratio. And that's without all the weight reduction items, ect.

Keep up the great modding work you've been doing. It only advances the hobby.

But I will have to agree with Tres & turbo. The Sbach (as E-flight produced it), is a truly awesome plane. It flies perfect pattern lines, and flies so straight and true. It's almost impossible to make it better. Adding more thrust to weight ratio will help to make it more "3D", but I don't see the need to try and transform it into one. It's just too good at what it does.
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Old Nov 16, 2011, 02:04 PM
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Quote:
Originally Posted by Tres Wright View Post
...
There are plenty of slow micro aircraft out there, I like the Beast/ Sbach/ Stryker specifically because they are fast and can be flown outdoors in moderate wind with no trouble. More power to you for trying to mod your Sbach into something it wasn't intended for, but implying that it is a poor design is just plain wrong...
Today I fly a plane new "Sbach 342" (with weight 41 grams) on the street with the wind up to 3 m/s .... No problem.
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Old Nov 16, 2011, 02:36 PM
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Quote:
Originally Posted by ICU View Post
...
What about working up a gear box for a 2s motor? I bet you could get greater than 2:1 thrust ratio. And that's without all the weight reduction items, ect...
ICU, Thank you.
Low voltage power supply is needed to achieve a record low weight.
With a voltage 7.4 V (2S) not possible to achieve such a small weight of the aircraft!
Get greater than 2:1 thrust ratio I can and with the power 3.7 V (1S), for example by means of the gearbox "HP05S1(4:1)E" (only on 2 grams heavier) http://www.rcgroups.com/forums/showp...&postcount=158
This gearbox "HP05S1(4:1)E" have thrust - 91g.!(3,5V;3 A; prop 160x70mm).
The ratio of thrust to weight = 91/(41+2)=2,1.
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Last edited by Vladimir88; Nov 16, 2011 at 02:57 PM.
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Old Nov 16, 2011, 07:19 PM
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turboparker's Avatar
East Bethel, MN USA
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Quote:
Originally Posted by Vladimir88 View Post
Joel ,thank you.

But you have the error:
In my setup AUW= 41 g(but not 45g).
Therefore, the in my Thrust:weight = 1,75 (but not 1,6).
Respectively my Wing loading = 3,5 oz/sq. ft.(but not 3,9)
Respectively reduced wing-loading - about 1,6 times(!!!) =5,7: 3,5 (but not 32 %).
(Or, this can calculate in another way- reduced wing-loading about = reduced weight (for the same wing area)= 65,4g: 41g = 1,6 !)
I was going by the weight you posted earlier, which was 45g.

3.5/5.9=0.593 Therefore, you reduced the wing-loading by nearly 41%. Even more impressive! Regarding the thrust-to-weight - it appears that you kept it essentially equal to a stock Sbach w/5030 & Hyp 180 2s pack.

What's the flight-time to 80% discharge with this setup?

Would be very interesting to see it fly with the HP05S1 gearbox!

Joel
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Old Nov 16, 2011, 07:28 PM
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[QUOTE=ICU;19891160What about working up a gear box for a 2s motor? I bet you could get greater than 2:1 thrust ratio. And that's without all the weight reduction items, ect.[/QUOTE]

ICU,

Put the 3000 Kv motor from the Stryker 180 into a stock-weight Sbach & you'll be over 2:1 w/ballistic top end on the 5043 + top-quality 2s pack. Use the Gee Bee's 5.25 x 3.5 prop for even more thrust. (The Gee Bee uses the Stryker 180 motor.)

Joel
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Old Nov 16, 2011, 08:29 PM
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Can it hover?
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