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Electric SSDR Motor Glider

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John.Roo

Well-Known Member
Joined
Oct 8, 2013
Messages
609
Location
Letohrad / Czech Republic
Hello!
The SSDR seems to me like interesting category allowing new designers to make nice prototypes. English is not my native language so I would like to ask few questions to understand basic rules.
MTOM with parachute is 315 kg, stall speed max. 65 kmph / 35 kts - OK. But is there any request for Empty Weight or maximum wing loading?
Quick explanation why I ask - in the document is mentioned rule from 2007 with EW 115 kg and wing loading not more than 10 kg/m2. I hope this is not included in 2016 definition in SSDR.

Sample weight balance sheet "from top".
MTOM = 315 kg
Pilot - 110 kg
BRS - 8 kg
Airframe - 120 kg
= I have available 77 kg for propulsion.
Motor, controler, prop - 20 kg
Battery - 50 kg (10 kWh)
Wiring, connectors + small reserve - 7 kg

I can imagine to make simple light electric airplane, but not with wing load 10 kg/m2 :)

Have a nice day!
Martin
 

hole in the ground

Active Member
Joined
May 27, 2018
Messages
32
Location
UK
Martin,

I think you are right in that there used to be a wing loading requirement, though my recollection is that it was an OR not an AND requirement. However this does not appear in more recently published documents. That said I’m trying to track down a definitive doc but surprisingly non-trivial.

Here is another one from 2018:
https://www.bmaa.org/files/til_045_ssdr_handbook.pdf
 

Basil

Active Member
HBA Supporter
Joined
Aug 19, 2017
Messages
39
Location
Countesthorpe UK
The origional SSDR rules didn't produce very practical aircraft. The current rules have no wing loading requirements, only the 35kt max stall in landing configuration. This has been met with wing loadings up to 40kg/m2 and full span flaperons and a moderately high lift section or 30kg/m2 or less without.
 

John.Roo

Well-Known Member
Joined
Oct 8, 2013
Messages
609
Location
Letohrad / Czech Republic
Martin,

I think you are right in that there used to be a wing loading requirement, though my recollection is that it was an OR not an AND requirement. However this does not appear in more recently published documents. That said I’m trying to track down a definitive doc but surprisingly non-trivial.

Here is another one from 2018:
https://www.bmaa.org/files/til_045_ssdr_handbook.pdf
Perfect - thanks for info!
So seems that I will start to dream a little bit as well :)
 

John.Roo

Well-Known Member
Joined
Oct 8, 2013
Messages
609
Location
Letohrad / Czech Republic
The origional SSDR rules didn't produce very practical aircraft. The current rules have no wing loading requirements, only the 35kt max stall in landing configuration. This has been met with wing loadings up to 40kg/m2 and full span flaperons and a moderately high lift section or 30kg/m2 or less without.
Thanks for this confirmation.
I agree - 10 kg/m2 is far too low...

35 kts stall speed + MTOM 300 (315) kg + nice flight characteristics are allowing more interesting constructions :)
 

hole in the ground

Active Member
Joined
May 27, 2018
Messages
32
Location
UK
House move stuff has delayed progress for the last little while. I am still progressing this in slow time though.
 
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