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by bjt4888
July 9th, 2020, 5:43 pm
Forum: Wright Stuff C
Topic: Wright Stuff C
Replies: 887
Views: 84578

Re: Wright Stuff C

Good to have a lot of questions. Angle of attack is relative to airflow. A good primer on aerodynamics from NASA is https://www.grc.nasa.gov/www/k-12/airplane/bga.html Explains concepts like angle of attack and includes some helpful graphics. Larger diameter propeller primary benefit is efficiency. ...
by bjt4888
July 8th, 2020, 9:28 am
Forum: Wright Stuff C
Topic: Wright Stuff C
Replies: 887
Views: 84578

Re: Wright Stuff C

I completely agree with Xiangyu, Crayola and Jasp, reading several years of these forums will only take a few hours and will give a solid base of understanding of the event. This should make for a good “Pandemic Project”. Also agree that it’s helpful and fun to build something to experiment with whi...
by bjt4888
March 29th, 2020, 7:05 pm
Forum: Wright Stuff C
Topic: Tweaks for 2021
Replies: 17
Views: 2021

Re: Tweaks for 2021

What about completely making all parts of the plane by hand, and no kits allowed. This would truly make the teams stand out from one another. For the vast majority of normal teams, the kits at least give them a place to start. You still have to be able to tune the plane (and you see very different ...
by bjt4888
March 21st, 2020, 8:26 pm
Forum: Wright Stuff C
Topic: Tweaks for 2021
Replies: 17
Views: 2021

Re: Tweaks for 2021

Xiangyu,

Rubber needed is .020” or possibly .025” if built heavier than the 500 mg minimum.

Roll will be manageable with this thinner rubber. Other designs I’ve flown like this have needed a lot of left wing washin too.

Fun to fly in the living room.

Brian T
by bjt4888
March 21st, 2020, 6:25 pm
Forum: Wright Stuff C
Topic: Tweaks for 2021
Replies: 17
Views: 2021

Re: Tweaks for 2021

coachchuckaahs wrote:
March 21st, 2020, 10:09 am
Brian: How about they do something like the Scraps plane (living room flyer size), but limit the rubber? Could be fun! Half a gram is not hard to reach, but could make min weight 3/4 gram?

Coach Chuck
Chuck,

That would be fun. Model boxes would smaller and cheaper too.

Brian T
by bjt4888
March 20th, 2020, 7:41 pm
Forum: Wright Stuff C
Topic: Tweaks for 2021
Replies: 17
Views: 2021

Re: Tweaks for 2021

Yes, 37-40% of the monoplane wing area for a reasonable stab area. I agree that a motor weight limit is a bit more challenging for event scheduling. I would challenge the event supervisors (me included) to come up with methods and tools to process motors quickly. The best idea I’ve seen is a simple ...
by bjt4888
March 20th, 2020, 5:11 pm
Forum: Wright Stuff C
Topic: Tweaks for 2021
Replies: 17
Views: 2021

Re: Tweaks for 2021

I agree that the most important change would be to increase stab size to around 37-40% of wing area. This one change would make the airplane trimmable. And, yes, the very small propeller was going a bit too far, in my opinion. With a prop spinning at around 2,400 rpm, many teams found that prop dama...
by bjt4888
March 19th, 2020, 3:56 pm
Forum: Wright Stuff C
Topic: What's Next???
Replies: 9
Views: 1413

Re: What's Next???

There is currently a new "Postal" event getting started. This is focused on a living room flyer, the Scraps plan. This is a small plane that can be built to the minimum 500mg weight with readily available wood. While this weight level may be a challenge coming form SO 8g minimum weight, they are sm...
by bjt4888
March 14th, 2020, 8:39 am
Forum: Wright Stuff C
Topic: Wright Stuff C
Replies: 887
Views: 84578

Re: Wright Stuff C

Xiangyu, Motor stick wood from the FF kits is probably not usable for Penny Plane. Most of the motor stick wood in the FF kits we received was 4 - 4.5 lb cu ft (very light and soft) and is too flexible for motor sticks until the 3k carbon tow is applied. As carbon tow on motor sticks is not allowed ...
by bjt4888
March 14th, 2020, 8:33 am
Forum: Wright Stuff C
Topic: Wright Stuff C
Replies: 887
Views: 84578

Re: Wright Stuff C

Xiangyu, Sorry, here's a better analysis of the wood used for Bill's Carbon Penny based upon calculated wood volume for each part. If you use 3/16" thick wood for the motor stick and follow the plan specs for .25" stick height dimension, tapered to .16" at both tips, 8.7 lb cu ft wood would give you...

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