Wright Stuff C

[xiangyu]

We're in the same boat and we're happy just to get into the gym let alone demand HVAC management. It makes tuning a challenge but I think the best teams will incorporate HVAC into their algorithms. I don't think it's wise to assume that HVAC will create an even playing field. Some teams will be able to quickly shift from conservative to higher performance settings based on not only HVAC, but smaller spaces, different ceilings, etc... For now we're happy to have a decent flying plane, but it is set for lower ceilings, smaller spaces, HVAC, etc... and it will be outclassed in higher, larger, calmer spaces where aggressive setups can thrive. This is where we're concentrating our work now (see above)

You'll never keep a basting vent from affecting the plane, but I think good HVAC tolerance goes hand-in-hand with good recovery from hits: conservative (forward) CG, higher decalage, and maybe even different prop/rubber. If we want maximum flight times we have to move the CG back and lower decalage (drag), but we already know that recovery from hits (and HVAC) will suffer. Ideally we will have logged different setups and will be able to switch back and forth based on the site, but we're not there yet (and we might not get there; our school is being difficult about gym access even when it's empty because of the liability we bring *sarcasm*).

Is your overall team coach a teacher/staff at the school? You could have them talk to the school so the school understands?

[lechassin]

Not to burden the forum with this kind of thing, but yes and yes, no dice. IMO an adequate testing venue is a serious obstacle for many of the teams, and we are left to fend for ourselves. That leaves me wondering if our time might be better spent elsewhere. IMO this event is supposed to be about the STEM process, not an exercise in butting heads with bureaucrats.

I suspect we're not the only ones with this sort of trouble: Now that the school is onto our "sneaking in", which we did as a last resort, our options are to squeeze in during normal hours (skip logging and generally rush), or come in when the school is closed (in which case the school-designated coach needs to also be there; he won't), or I can rent the space that I already pay for with taxes, lol.

So yeah, I say "harumph" on behalf of all of us. Join the Pompom team and then you'll have all the resources you'll ever need *eyeroll*.

[coachchuckaahs]

Wouldn't be the first to need to rent a facility. As a homeschool team, that is our only option! So fundraising becomes a part of life. But, that is true in a STEM career as well!

In terms of HVAC, we had talked to administration at the facility, and they said it was not something they can control, we have to live with it. In an early morning session, the AC came on and broke a plane (F1D). A facilities guy walked through and I asked if there is anything that can be done. He said it could not be tied to the calendar system, but that he could disable HVAC from his cell phone. From then on we were best of buddies!

Good luck resolving your facility issues. But do NOT give up logging. Without logging you are just wasting gym time anyway. Log should not take much of the time, but no log means nothing is learned.

Coach Chuck

[lechassin]

We've got the day off so we fiddled with the wing offset, using two fixed mounts on the LE and TE each, consisting of 1/32" balsa uprights that straddle the motor stick with a small prominence that grabs an orthodontic rubber band. A thin triangular shim under the leading edge adjusts the right and left turn decalage.

For those of you who can't get to the gym often (because you haven't mastered bureaucracies as is apparently expected for this event), or who don't have a large home to try out basic settings, or who live in windy climates, we have some useful numbers to share; this is for those who prefer to eliminate banking without warping the wings.

We did left turns first and the bank is almost but not completely gone at 1/2" wing offset. We didn't fiddle more that way because it's very close. Knowing we wouldn't need as much offset to the right, we chose 1/2" again and it's dead on: cruising is perfectly level, no banking at all. Surprisingly the launch does not bank left, there's obvious side-slipping and a tighter radius than cruising (higher air velocity from the prop over the rudder). Because there's less banking throughout the flight, the decalage is now down to 3mm left and 2mm right with the CG somewhere between our extremes of 23mm and 31mm, tweaked for good climb and end-of-flight. The plane carries 3 grams of rubber easily. Also as expected, more rudder deflection is needed to keep a good radius, about 5mm either way. This is in the house, we will hopefully assess in the gym, but it looks very promising.

If for whatever reason you decided to scratch build based on the guidelines I posted, you can easily incorporate this feature into the design, and I think 1/2" would be a good start for any plane this year (certainly the bipes).

[xiangyu]

Update on my progress: After two weeks of "playing around" with my bi-planes, I've decided to give up. ( ) at least for now. I just can't get the biplane to work consistently and no matter what I do there appears to be stall problems. Anyways. That being said, my team and I went back to the mono plane design, and is able to increase our times to 1:25 consistently to the right. However, we seem to be struggling with going to the left. The plane backs too much and can't climb very high because of this. I've tried to add washins and it helps. Our practice sessions ended while I was in the middle of adding more washins. It seems that I am adding a lot of washings (now at 0.024 in or 6 sticker for those of you with the ff kits) which is helping. Should I continue to add washins next time I fly? Is there an amount of washin that I shouldn't cross?

Xiangyu

[lechassin]

1'25" with a higher wing loading/two-bladed prop/wing warping! I don't have any help to offer because our design is so different from yours and I don't have much experience with this otherwise, but I'm impressed with your times.

[xiangyu]

1'25" with a higher wing loading/two-bladed prop/wing warping! I don't have any help to offer because our design is so different from yours and I don't have much experience with this otherwise, but I'm impressed with your times.

Thanks! I did pm you a question about propellers idk if you saw that.

Xiangyu

[lechassin]

Oops, sorry I missed that, I took care of it.

I couldn't stand the slight residual left banking so I fiddled some more: the left wing offset is 9/16", right is still 1/2". Makes sense due to prop torque.

Definitely easy to reproduce: I did the mod to Luke's first plane and it flies perfectly flat too. I think it's better than warping the wings, but we'll see!

[bjt4888]

Update on my progress: After two weeks of "playing around" with my bi-planes, I've decided to give up. ( ) at least for now. I just can't get the biplane to work consistently and no matter what I do there appears to be stall problems. Anyways. That being said, my team and I went back to the mono plane design, and is able to increase our times to 1:25 consistently to the right. However, we seem to be struggling with going to the left. The plane backs too much and can't climb very high because of this. I've tried to add washins and it helps. Our practice sessions ended while I was in the middle of adding more washins. It seems that I am adding a lot of washings (now at 0.024 in or 6 sticker for those of you with the ff kits) which is helping. Should I continue to add washins next time I fly? Is there an amount of washin that I shouldn't cross?

Xiangyu

Xiangyu,

What is the washin amount as measured at the wingtip? The kit plans recommend 3/16” of washin for either direction flight for the biplane.

If I am remembering the FF kit correctly (there are eight kit boxes in my workshop), the “stickers” are shims that “wedge” the wing mount and cause twist and washin in the wing.

First, you probably want want to be sure that the wing I’d perfectly straight (no twists) before it is mounted on the fuselage. The kit instructions give good directions on how to use the diagonal struts to straighten a wing if it has twist in it when it is not mounted on the fuselage.

After the wing is without twists (again, wing by itself and not in the tubes and on the fuselage) the shims (stickers) should twist in washin correctly for either flight direction.

Keep at it, the biplane is definitely solvable and worth it.

Brian T

[xiangyu]

Update on my progress:

Continuing to increase little by little everytime . It was pretty successful practice today as my plane broke the 1:30 mark a couple of times and I can fairly consistently get 1:26-1:28. I actually filmed a couple flights today and would love it if someone has any feedback for me on how to continue to increase my flight times. There are a couple of weeks until my first invitational so I'm just trying to do my personal best! (Albeit I probably won't medal, it's still fun to get a high time!).

See two of my flights here (Please excuse the bad quality/camera work, my partner couldn't make it tonight so I had to launch the plane then back away and film - Also idk what happened with my phone's camera during the left fly lol, so blurry... ):

~1:28 to the left (now with a piece of balsawood as shim and working better - thank you vehicleguy for the suggestion): https://youtu.be/IDovV9TofBY

~1:31 to the right: https://youtu.be/eybq4oVk3LM

Both flights end with about 20-30 (times 15 so 300-450 actual) winds left. PM me if you have ideas to help me improve but need more info.

This is a strategy question for competition; Is it potentially beneficial to fly some trim flights? With this year's shorter flights are people recommending flying a trim flight to see if flight radius/other factors are maximized after adjustment?

As always, any help is greatly apprecited
Xiangyu