Flight Trimming
-
- Member
- Posts: 1654
- Joined: April 30th, 2007, 7:54 am
- Has thanked: 0
- Been thanked: 29 times
Re: Flight Trimming
Actually, superglue works just fine for WS. Trick is to not use to much.
Search for previous discussion on precision mircro superglue applicator (two pin stuck through a piece of scrap stick, balsa or bass). Or read my glue article on the National SO web page for Wright Stuff http://soinc.org/sites/default/files/up ... weight.pdf
As I say there, used properly, CA adds very little weight over balsa cement. In my experience, the time savings with CA is worth it for younger fliers. Its as easy to hit the 7.0 gm minimum with CA as with balsa cement.
Jeff Anderson
Livonia, MI
Search for previous discussion on precision mircro superglue applicator (two pin stuck through a piece of scrap stick, balsa or bass). Or read my glue article on the National SO web page for Wright Stuff http://soinc.org/sites/default/files/up ... weight.pdf
As I say there, used properly, CA adds very little weight over balsa cement. In my experience, the time savings with CA is worth it for younger fliers. Its as easy to hit the 7.0 gm minimum with CA as with balsa cement.
Jeff Anderson
Livonia, MI
- blue cobra
- Exalted Member
- Posts: 417
- Joined: April 9th, 2009, 6:10 pm
- Division: Grad
- State: NY
- Has thanked: 0
- Been thanked: 0
Re: Flight Trimming
Right now, my cambered horizontal stabilizer has negative AoA. with a 10cm chord, the LE is about 1/8 inch lower than the TE. I assume 0 or positive AoA would be better, so to get it to fly right with positive incidence on the tail should I move my wing forward? This is all assuming I eventually get gym time this year...
In full color since 2006
- WrightStuffMonster
- Exalted Member
- Posts: 62
- Joined: September 14th, 2005, 10:56 pm
- Division: Grad
- State: AK
- Has thanked: 0
- Been thanked: 0
Re: Flight Trimming
Nope you are incorrect. A negative AoA in the tail is quite normal and a good thing. Your plane will tend to be alot more stable this way. However, I always trimmed zero in the wing and zero in the tail when I went for maximum times. There was a big danger in doing that though as my plane would drop about 15 feet after every hit.blue cobra wrote:Right now, my cambered horizontal stabilizer has negative AoA. with a 10cm chord, the LE is about 1/8 inch lower than the TE. I assume 0 or positive AoA would be better, so to get it to fly right with positive incidence on the tail should I move my wing forward? This is all assuming I eventually get gym time this year...
-Alaska
Eagle River High School Class 09
Nationals:
1st Wright Stuff Kansas 07
1st Robot Ramble Washington D.C. 08
Stanford University Class 2013
Eagle River High School Class 09
Nationals:
1st Wright Stuff Kansas 07
1st Robot Ramble Washington D.C. 08
Stanford University Class 2013
- Brucester
- Member
- Posts: 43
- Joined: February 16th, 2010, 9:38 pm
- Division: B
- State: PA
- Has thanked: 0
- Been thanked: 0
Re: Flight Trimming
This is a tad off topic, but since there's no "Flight Log" topic, I wanted to ask a question about flight logs. At the recent Solon tournament I had 7 parameter (now I have 13), but two of those parameters were back wing post and front wing post adjustments relative to premarked lines on the plane that were getting decent flight times. The event director, while checking my flight log, told me a parameter had to be a numerical value and adjustments do not count. I say noting adjustments is one of the most important things you can do in a flight log. He said, "I'll spare you this time, but I'm trying to prepare you for regionals, where they would turn this flight log down because those are not parameters." I didn't argue, but just wanted to know your opinion on the dilemma.
Thanks as always,
Brucester
Thanks as always,
Brucester
2011 Nationals:
3rd - Bottle Rockets
7th - Storm the Castle
7th - Towers
22nd - Experimental Design
3rd - Bottle Rockets
7th - Storm the Castle
7th - Towers
22nd - Experimental Design
- blue cobra
- Exalted Member
- Posts: 417
- Joined: April 9th, 2009, 6:10 pm
- Division: Grad
- State: NY
- Has thanked: 0
- Been thanked: 0
Re: Flight Trimming
That 's strange, and I certainly disagree. My flight log had a parameter as "adjustments" including things as vague as "adjust rudder" and wasn't even about the plane I was using and it was still accepted at States. Also AoA is very important. Now, did you just have 'moved up' or 'moved down' or did you take a measurement? If the former then I think even that judge would accept the latter, not to mention having a more useful flight log for yourself.
Not to distract from your question, but as I mentioned my horizontal stabilizer has a LE an eigth inch lower than TE along a 10 cm chord. As I understand, this produces negative lift but provides stability. If I increased AoA to, say, one sixteenth difference, this would potentially provide less negative lift but still have my plane sufficiently stable, eh? This would require me to move my wing forward to maintain my current flight behavior? (if I get any gym time. grrr)
Not to distract from your question, but as I mentioned my horizontal stabilizer has a LE an eigth inch lower than TE along a 10 cm chord. As I understand, this produces negative lift but provides stability. If I increased AoA to, say, one sixteenth difference, this would potentially provide less negative lift but still have my plane sufficiently stable, eh? This would require me to move my wing forward to maintain my current flight behavior? (if I get any gym time. grrr)
In full color since 2006
- Brucester
- Member
- Posts: 43
- Joined: February 16th, 2010, 9:38 pm
- Division: B
- State: PA
- Has thanked: 0
- Been thanked: 0
Re: Flight Trimming
It was moved up and moved down, but with a measurement such as 1/16", 1/32", and 1/8", and those movements were relative to lines on the wingposts. Well thanks for clarifying.
Thanks,
Brucester
Thanks,
Brucester
2011 Nationals:
3rd - Bottle Rockets
7th - Storm the Castle
7th - Towers
22nd - Experimental Design
3rd - Bottle Rockets
7th - Storm the Castle
7th - Towers
22nd - Experimental Design
-
- Member
- Posts: 1654
- Joined: April 30th, 2007, 7:54 am
- Has thanked: 0
- Been thanked: 29 times
Re: Flight Trimming
The supervisor was just wrong, there is no definition of what a parameter is except the required three, and those are practically wide open. But he is the supervisor. If he's doing your regional or state contest, you'd better listen.
I think you are taking the right approach with far more than the minimum six. Do try to keep them numerical and relevant, but nothing says they have to be.
As to tail angle of attack, just because the tail is nose down wrt the boom DOESN'T mean it is negative lift. Curved surfaces like these can still have positive lift with very negative angles of attack.
And consider, its not really the tail angle of attack relative to the wing, but relative to the air that's important. Does your plane fly level, but nose high? If so, the tail angle of attack MAY be positive. Certainly less negative than you think.
One way to tell, where is your cg now? Is it at the back wing post or pretty near on a wide wing chord? If so, your tail is lifting positive, has to, to balance. Think about it. If the cg is behind the wing (on narrow wings it should be, may not be on wide wings), then your tail is definitely lifting.
Jeff Anderson
Livonia, MI
I think you are taking the right approach with far more than the minimum six. Do try to keep them numerical and relevant, but nothing says they have to be.
As to tail angle of attack, just because the tail is nose down wrt the boom DOESN'T mean it is negative lift. Curved surfaces like these can still have positive lift with very negative angles of attack.
And consider, its not really the tail angle of attack relative to the wing, but relative to the air that's important. Does your plane fly level, but nose high? If so, the tail angle of attack MAY be positive. Certainly less negative than you think.
One way to tell, where is your cg now? Is it at the back wing post or pretty near on a wide wing chord? If so, your tail is lifting positive, has to, to balance. Think about it. If the cg is behind the wing (on narrow wings it should be, may not be on wide wings), then your tail is definitely lifting.
Jeff Anderson
Livonia, MI
-
- Member
- Posts: 116
- Joined: March 25th, 2009, 5:37 am
- Division: B
- Has thanked: 0
- Been thanked: 0
Flight Trimming
I have a problem in trimming flying on a big wing when I try to use the Ikara broad blade in that it throws off my cg. I fly real good (1m30 on a .080 half motor) with the regular 8 7/8 Ikara blade when the the cg is 5/8 in. behind the rear post but I keep getting ceiling bumps in a 24 ft gym. But with the broad blade I lose .4 gr of ballast and the cg goes forward. Moving the rear post down a 1/16 gets me flying but I also lose 20+ seconds.
I WILL RETURN TO PHILMONT IN JULY!
07 Reg 1st BLG, 3rd WV.
08 Reg 1st Twr, 2nd BLG
State 1st Twr
09 Reg 1st WS, PSL and Crave the Wave, 2nd Robo-X, EB
State 1st EB, 3rd WS
10 Reg 1st EB, PSL, 2nd WS, Disease Det., 3rd Traj.
State 1st EB, PSL, 2nd WS, 3rd Disease Det.
07 Reg 1st BLG, 3rd WV.
08 Reg 1st Twr, 2nd BLG
State 1st Twr
09 Reg 1st WS, PSL and Crave the Wave, 2nd Robo-X, EB
State 1st EB, 3rd WS
10 Reg 1st EB, PSL, 2nd WS, Disease Det., 3rd Traj.
State 1st EB, PSL, 2nd WS, 3rd Disease Det.
-
- Member
- Posts: 52
- Joined: January 22nd, 2010, 5:40 pm
- Division: Grad
- State: CA
- Has thanked: 0
- Been thanked: 0
Re: Flight Trimming
The broad blade should not weigh .4 g more than the regular blade if trimmed. Have you trimmed your propellers to 20 cm? If you have, then try trimming little by little the width of the broad blade.StampingKid wrote:I have a problem in trimming flying on a big wing when I try to use the Ikara broad blade in that it throws off my cg. I fly real good (1m30 on a .080 half motor) with the regular 8 7/8 Ikara blade when the the cg is 5/8 in. behind the rear post but I keep getting ceiling bumps in a 24 ft gym. But with the broad blade I lose .4 gr of ballast and the cg goes forward. Moving the rear post down a 1/16 gets me flying but I also lose 20+ seconds.
-
- Member
- Posts: 116
- Joined: March 25th, 2009, 5:37 am
- Division: B
- Has thanked: 0
- Been thanked: 0
Re: Flight Trimming
The regular blade is 1.76 gr trimmed to 20cm. The broad blade is 2.16 gr. trimmed to 20 cm and with everything behind the spar trimmed away. Which is not right? I cannot trim anymore off the borad blade. But if it is the one that is not right I can get another to trim.StampingKid wrote:
I have a problem in trimming flying on a big wing when I try to use the Ikara broad blade in that it throws off my cg. I fly real good (1m30 on a .080 half motor) with the regular 8 7/8 Ikara blade when the the cg is 5/8 in. behind the rear post but I keep getting ceiling bumps in a 24 ft gym. But with the broad blade I lose .4 gr of ballast and the cg goes forward. Moving the rear post down a 1/16 gets me flying but I also lose 20+ seconds.
Leetx replied:
The broad blade should not weigh .4 g more than the regular blade if trimmed. Have you trimmed your propellers to 20 cm? If you have, then try trimming little by little the width of the broad blade.
I WILL RETURN TO PHILMONT IN JULY!
07 Reg 1st BLG, 3rd WV.
08 Reg 1st Twr, 2nd BLG
State 1st Twr
09 Reg 1st WS, PSL and Crave the Wave, 2nd Robo-X, EB
State 1st EB, 3rd WS
10 Reg 1st EB, PSL, 2nd WS, Disease Det., 3rd Traj.
State 1st EB, PSL, 2nd WS, 3rd Disease Det.
07 Reg 1st BLG, 3rd WV.
08 Reg 1st Twr, 2nd BLG
State 1st Twr
09 Reg 1st WS, PSL and Crave the Wave, 2nd Robo-X, EB
State 1st EB, 3rd WS
10 Reg 1st EB, PSL, 2nd WS, Disease Det., 3rd Traj.
State 1st EB, PSL, 2nd WS, 3rd Disease Det.
Who is online
Users browsing this forum: No registered users and 2 guests