Pattern Biplane
10-12-2017, 05:45 PM
#104
I'm sure that Don can explain better but here in the US we run 4 classes of AMA pattern and FAI is kind of a stand alone class. Being in a different country, there are no AMA pattern classes. Which brings up the question of just how the rest of the world separates their classes.
10-12-2017, 05:59 PM
#105
There are lots of variations around the world. Here in USA, keeping 4 rounds out of 6 can get very interesting if someone wins 4 rounds after either 4 or 5 rounds and then does not fly the last two or last round. That can shift the normalized scores for the rounds the winner does not fly higher meaning those last two rounds become more important in determining the placement for 2nd on down.
I usually tell my pattern students each round may count, you can't approach the contest with the idea of throw away rounds or warm up rounds. You might get caught napping..... ;-)
Woodie
I usually tell my pattern students each round may count, you can't approach the contest with the idea of throw away rounds or warm up rounds. You might get caught napping..... ;-)
Woodie
10-12-2017, 06:00 PM
#106
I'm sure that Don can explain better but here in the US we run 4 classes of AMA pattern and FAI is kind of a stand alone class. Being in a different country, there are no AMA pattern classes. Which brings up the question of just how the rest of the world separates their classes.
We have 4 classes; Sportsman, Advanced, Expert ( which is the FAI Advanced Schedule) and FAI-F3A.
10-12-2017, 06:07 PM
#107
There are lots of variations around the world. Here in USA, keeping 4 rounds out of 6 can get very interesting if someone wins 4 rounds after either 4 or 5 rounds and then does not fly the last two or last round. That can shift the normalized scores for the rounds the winner does not fly higher meaning those last two rounds become more important in determining the placement for 2nd on down.
I usually tell my pattern students each round may count, you can't approach the contest with the idea of throw away rounds or warm up rounds. You might get caught napping..... ;-)
Woodie
I usually tell my pattern students each round may count, you can't approach the contest with the idea of throw away rounds or warm up rounds. You might get caught napping..... ;-)
Woodie
Normalising makes it interesting as well. I've had my best score dropped due to normalising.
How are the 2 dropped rounds determined?
10-13-2017, 05:14 PM
#108
I believe it is just the lowest two scoring rounds are dropped.
Back to more sanding, got both upper wings pretty much done. Obviously there will be more sanding after the ailerons are cut out and faced. Still had to put them on the scale though. I took a few minutes to weigh the wings, stabs, motor and controller, landing gear, batteries and servos. So far all those components weigh 6.5 lbs. I am shooting for 2 lbs for an empty fuselage and that would bring it up to 8.5 lbs. I think 2 lbs for paint, linkages, RX and RX battery and some hardware is a fairly accurate estimate. I would be very happy if I could get a finished weight of 10.5 lbs.
Back to more sanding, got both upper wings pretty much done. Obviously there will be more sanding after the ailerons are cut out and faced. Still had to put them on the scale though. I took a few minutes to weigh the wings, stabs, motor and controller, landing gear, batteries and servos. So far all those components weigh 6.5 lbs. I am shooting for 2 lbs for an empty fuselage and that would bring it up to 8.5 lbs. I think 2 lbs for paint, linkages, RX and RX battery and some hardware is a fairly accurate estimate. I would be very happy if I could get a finished weight of 10.5 lbs.
10-13-2017, 06:14 PM
#109
I believe it is just the lowest two scoring rounds are dropped.
Back to more sanding, got both upper wings pretty much done. Obviously there will be more sanding after the ailerons are cut out and faced. Still had to put them on the scale though. I took a few minutes to weigh the wings, stabs, motor and controller, landing gear, batteries and servos. So far all those components weigh 6.5 lbs. I am shooting for 2 lbs for an empty fuselage and that would bring it up to 8.5 lbs. I think 2 lbs for paint, linkages, RX and RX battery and some hardware is a fairly accurate estimate. I would be very happy if I could get a finished weight of 10.5 lbs.
Back to more sanding, got both upper wings pretty much done. Obviously there will be more sanding after the ailerons are cut out and faced. Still had to put them on the scale though. I took a few minutes to weigh the wings, stabs, motor and controller, landing gear, batteries and servos. So far all those components weigh 6.5 lbs. I am shooting for 2 lbs for an empty fuselage and that would bring it up to 8.5 lbs. I think 2 lbs for paint, linkages, RX and RX battery and some hardware is a fairly accurate estimate. I would be very happy if I could get a finished weight of 10.5 lbs.
10-13-2017, 08:24 PM
#114
Not very much, my sheeting process makes for a very strong bond between the foam and balsa. Granted if it weren't for the struts that will connect the wings they would most likely fail. I have always thought that we build our models way stronger then need be in most cases. Typically we build our models to survive transportation/handling and to survive the occasional bad landing. The last airplane I designed was for warbird pylon racing. 62" span, glass fuse, balsa sheeted foam wing, all paint. Complete with retracts, 6 servos and a YS 115 it tips the scales at 6.25 lbs. Note how thin the wing is.
10-13-2017, 08:38 PM
#115
Not very much, my sheeting process makes for a very strong bond between the foam and balsa. Granted if it weren't for the struts that will connect the wings they would most likely fail. I have always thought that we build our models way stronger then need be in most cases. Typically we build our models to survive transportation/handling and to survive the occasional bad landing. The last airplane I designed was for warbird pylon racing. 62" span, glass fuse, balsa sheeted foam wing, all paint. Complete with retracts, 6 servos and a YS 115 it tips the scales at 6.25 lbs. Note how thin the wing is.
Looking forward to the rest of the build.
10-14-2017, 03:08 PM
#116
Quite a productive day today. I was able to get the bottom wing lined up and mounted. It is sitting at .7 degrees incidence as measured using the upper wing as the reference. The upper wing is set to zero using the nose ring as a reference that is set to one of the seams along the length of the fuselage. I think I have used enough reference points to make sure everything is square. At this point the only thing that needs attention is there is a 1/8" difference in wing gap between the right and left side. Just a little fine tuning to the wing saddle on one side will fix that right up.
10-14-2017, 03:58 PM
#117
Quite a productive day today. I was able to get the bottom wing lined up and mounted. It is sitting at .7 degrees incidence as measured using the upper wing as the reference. The upper wing is set to zero using the nose ring as a reference that is set to one of the seams along the length of the fuselage. I think I have used enough reference points to make sure everything is square. At this point the only thing that needs attention is there is a 1/8" difference in wing gap between the right and left side. Just a little fine tuning to the wing saddle on one side will fix that right up.
Do you have any stagger on the wings?
10-14-2017, 05:03 PM
#118
Yes, there is a 2" stagger. The next step will be to fill in a couple areas on the fuselage in front and behind the lower wing, match up the wing fillets on the fuselage to the top wing a little better and then fine tune all the fuselage corner radius. Then finally I will be able to start applying glass to the fuselage.I am hopeful that the mold production will be started mid November. I will not be able to do much of anything next week. One week a month I have to do 12 hr shifts, next week is my week.
10-14-2017, 06:36 PM
#119
10-14-2017, 08:08 PM
#120
Thanks Ken. The good thing about having to work those hours it will allow me some down time to think through a few details that I may have otherwise executed the first option that comes to mind rather then weigh the benefits of a second or third option. If you noticed, I haven't made a rudder yet. My first idea was to just do a balsa sheeted foam version just like the stabs and wings. After some thought I am leaning towards a molded fiberglass rudder. Then come more options, flared TE or not, what thickness should the TE be? The one thing that I am thinking is that during the layup I can add a strip of Kevlar at the LE that would extend onto the mold flange. This Kevlar strip would become the rudder hinge. Having to not do traditional hinges would save even more weight. As they say " it's all in the details ". I sure hope that after all this effort on those details that the design is sound.
10-14-2017, 08:57 PM
#121
Yes, there is a 2" stagger. The next step will be to fill in a couple areas on the fuselage in front and behind the lower wing, match up the wing fillets on the fuselage to the top wing a little better and then fine tune all the fuselage corner radius. Then finally I will be able to start applying glass to the fuselage.I am hopeful that the mold production will be started mid November. I will not be able to do much of anything next week. One week a month I have to do 12 hr shifts, next week is my week.
With the top wing 0 and the bottom +.7 and I presume the stab at 0, it will be interesting to see how it flys and if the stab needs to be adjusted.
10-15-2017, 06:49 AM
#122
Agreed. I read through all the posts in the biplane incidence thread and came to the conclusion that there were many ways to go. I even saw one design that used washout but only on the top wing. My current Biplane, a Circus Hobbies Reed Falcon has both wings set to zero as well as the stab but has 2 degrees up thrust. It flies great without any changes other then CG and a downline mix. The Goldberg and Dave Patrick Ultimates run zero on the wings as well but 2 degrees positive incidence on the stab.From where I sit I think my best plan of attack on this one is to make the bottom wing fixed and have adjusters on the top wing and stabs. Using a Hacker C50 motor with the 6.7:1 gearbox will also make thrust line changes quick and easy with the mount design I have planned.
10-15-2017, 05:31 PM
#123
The only work I got done today was to get the filler blocks in at the LE and TE so now the fuse meets up with the lower wing nicely. The only planned work for this week is to put some Mylar packing tape on the wing center section on top and then lay a couple layers of glass cloth onto the tape. When that cures the wing will then get potted to the fuse and when pulled back off will leave a perfectly fitted wing saddle.
10-25-2017, 05:01 PM
#124
I'm now done going over the fuselage with a fine tooth comb. Here is the final mock up and now she is all taken apart and the fuselage plug glassing has begun. I have also sealed the wing saddle by using the wing as a mold. A great way to ensure that the wing is a perfect fit.