Wright Stuff C
-
- Member
- Posts: 886
- Joined: June 16th, 2013, 12:35 pm
- Division: C
- State: MI
- Has thanked: 0
- Been thanked: 51 times
Re: Wright Stuff C
Balsa,
We generally start testing by selecting a conservative CG based upon the neutral point and a slightly excessive decalage angle (difference between the wing and stabilizer incidence angles). We fly this setup, maybe slightly reducing wing incidence if stalling, with a variety of propellers (usually increasing pitch gradually) and a variety of rubber densities andmotor lengths. Once we have this trim setup flying well, we will start pushing the CG back till stalling (or,intense case of this year’s tandem, mushing and wandering) and then move the CG jus forward of this point or reduce the wing incidence, or try both adjustments separately on different flights.
We continue iterations of the above till changes stop increasing duration or till too unstable to survive air disturbances or ceiling hits.
Good luck and have fun at Nationals.
Brian T
We generally start testing by selecting a conservative CG based upon the neutral point and a slightly excessive decalage angle (difference between the wing and stabilizer incidence angles). We fly this setup, maybe slightly reducing wing incidence if stalling, with a variety of propellers (usually increasing pitch gradually) and a variety of rubber densities andmotor lengths. Once we have this trim setup flying well, we will start pushing the CG back till stalling (or,intense case of this year’s tandem, mushing and wandering) and then move the CG jus forward of this point or reduce the wing incidence, or try both adjustments separately on different flights.
We continue iterations of the above till changes stop increasing duration or till too unstable to survive air disturbances or ceiling hits.
Good luck and have fun at Nationals.
Brian T
-
- Member
- Posts: 28
- Joined: February 6th, 2019, 4:35 am
- Division: C
- Has thanked: 0
- Been thanked: 1 time
Re: Wright Stuff C
Thanks, Brian for clarifying my questions with your own practices, I really appreciate it. I'll apply these in my upcoming, short but important flying sessions.bjt4888 wrote:Balsa,
We generally start testing by selecting a conservative CG based upon the neutral point and a slightly excessive decalage angle (difference between the wing and stabilizer incidence angles). We fly this setup, maybe slightly reducing wing incidence if stalling, with a variety of propellers (usually increasing pitch gradually) and a variety of rubber densities andmotor lengths. Once we have this trim setup flying well, we will start pushing the CG back till stalling (or,intense case of this year’s tandem, mushing and wandering) and then move the CG jus forward of this point or reduce the wing incidence, or try both adjustments separately on different flights.
We continue iterations of the above till changes stop increasing duration or till too unstable to survive air disturbances or ceiling hits.
Good luck and have fun at Nationals.
Brian T
Though, I was wondering how you calculate the NP - do you have a special spreadsheet just to calculate it because I've seen some people use calculators to find the NP and SSM, but I can't seem to find one that works or don't know how to make one myself?
-
- Member
- Posts: 886
- Joined: June 16th, 2013, 12:35 pm
- Division: C
- State: MI
- Has thanked: 0
- Been thanked: 51 times
Re: Wright Stuff C
Balsa,
We use the Bernie Hunt NP/Design spreadsheet. Fern Rash also has published a good one. Both are available in the Yahoo Group “Indoor_Construction” in the Files section. Bernie’s sheet doesn’t calculate CG perfectly for heavy airplanes like we use for SO but we “trick” the spreadsheet by entering the ballast location different than actual in order to have the sheet calculate the CG correctly and thereby show the SSM correctly.
If you have detailed questions about use of the sheet, spend me a PM.
Brian T
We use the Bernie Hunt NP/Design spreadsheet. Fern Rash also has published a good one. Both are available in the Yahoo Group “Indoor_Construction” in the Files section. Bernie’s sheet doesn’t calculate CG perfectly for heavy airplanes like we use for SO but we “trick” the spreadsheet by entering the ballast location different than actual in order to have the sheet calculate the CG correctly and thereby show the SSM correctly.
If you have detailed questions about use of the sheet, spend me a PM.
Brian T
-
- Member
- Posts: 28
- Joined: February 6th, 2019, 4:35 am
- Division: C
- Has thanked: 0
- Been thanked: 1 time
Re: Wright Stuff C
Thanks sm again Brian, I'll try to use them and gather some accurate data.bjt4888 wrote:Balsa,
We use the Bernie Hunt NP/Design spreadsheet. Fern Rash also has published a good one. Both are available in the Yahoo Group “Indoor_Construction” in the Files section. Bernie’s sheet doesn’t calculate CG perfectly for heavy airplanes like we use for SO but we “trick” the spreadsheet by entering the ballast location different than actual in order to have the sheet calculate the CG correctly and thereby show the SSM correctly.
If you have detailed questions about use of the sheet, spend me a PM.
Brian T
-
- Member
- Posts: 288
- Joined: August 1st, 2017, 8:02 am
- Division: Grad
- State: IL
- Has thanked: 0
- Been thanked: 0
Re: Wright Stuff C
Hey, I’m not sure if anyone from Fossil Ridge is here. But they left a torque meter and winder on top of the thermostat right by the entrance.
Deleted
-
- Member
- Posts: 16
- Joined: April 6th, 2019, 6:26 pm
- Division: C
- State: CA
- Has thanked: 0
- Been thanked: 0
Re: Wright Stuff C
There was practice today!?DarthBuilder wrote:Hey, I’m not sure if anyone from Fossil Ridge is here. But they left a torque meter and winder on top of the thermostat right by the entrance.
- klastyioer
- Member
- Posts: 429
- Joined: April 22nd, 2018, 4:46 pm
- Division: C
- State: PA
- Pronouns: She/Her/Hers
- Has thanked: 2 times
- Been thanked: 2 times
- Contact:
Re: Wright Stuff C
no...?NorCalplaya wrote:There was practice today!?DarthBuilder wrote:Hey, I’m not sure if anyone from Fossil Ridge is here. But they left a torque meter and winder on top of the thermostat right by the entrance.
it's not about the medals; go out there and have fun. make progress, learn a few things and have one heck of a time; that's all that matters.
Check out Klastyioer's Userpage!
Check out Klastyioer's Userpage!
-
- Member
- Posts: 210
- Joined: June 3rd, 2018, 5:32 pm
- Has thanked: 8 times
- Been thanked: 4 times
- CrayolaCrayon
- Member
- Posts: 346
- Joined: October 25th, 2017, 8:24 am
- Division: C
- State: PA
- Has thanked: 16 times
- Been thanked: 5 times
Re: Wright Stuff C
1st: Albequerque HS with a 5:09
2nd: Bayard Rustin HS with a 4:25
3rd: Northville HS with a 3:50
From what I observed ^
2nd: Bayard Rustin HS with a 4:25
3rd: Northville HS with a 3:50
From what I observed ^
MIT '25
MIT Wright Stuff ES '22
BirdSO Wright Stuff ES '22
MIT Wright Stuff ES '22
BirdSO Wright Stuff ES '22
Who is online
Users browsing this forum: No registered users and 5 guests