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since this thread is about models, this question is probably better here

I bought an FAI model for for school SO tryouts, But it turned out 11 grams, and flew horribly. Compared to the foam planes of others, it got me a third at tryouts, but i don't understand what made it perform so horribly. After building many good competition planes from scratch, to less than minimum weight from hobby store wood, i built the second plane from the FAI set, and it turned out nearly as badly flying as the first. Is there any explanation for this ? or is it just inexperienced building

kjhsscioly wrote:since this thread is about models, this question is probably better here

I bought an FAI model for for school SO tryouts, But it turned out 11 grams, and flew horribly. Compared to the foam planes of others, it got me a third at tryouts, but i don't understand what made it perform so horribly. After building many good competition planes from scratch, to less than minimum weight from hobby store wood, i built the second plane from the FAI set, and it turned out nearly as badly flying as the first. Is there any explanation for this ? or is it just inexperienced building

FAI sells lots of kits so which one was it? If you have had so much experience with other competition planes, why opt for a kit? Instructions can be tough to interpret sometimes. If an experienced flier designed the airplane they may not have written instructions that were easy to understand. If it was an airplane designed for indoor, did the instructions suggest what finished weights should be?

You mention "foam" airplanes and usually we associate those with toy manufacturers, scale designs or small RC. Describe the foam planes better. Were they possibly lighter than yours? Were they rubber powered? Were they commercial style kits or home grown designs?

When your airplane flew poorly, was it stable with a short flight or were there other issues?

Generally FAI provides quality items so some detail would be beneficial.

Good Luck

it was a 2009 "fun science", ordered from FAI, but the label said freedom flight. I bought the set before i began wright stuff, for tryouts... i built one for tryouts, one after state competition (the set comes with two planes). The plane was made for scioly, so i know all the specs and weights were correct. the instruction packet was at least 30 pages long... no misunderstandings possible. the plane had a odd stall like problem, where it would stall backward. It would go up about two feet, then stop, and fall backwards. However, i fixed that with some trimming, but it wouldn't go up at all anyway. I tried with about a thousand winds, but it reacted no differently, even with a change in rubber size.

On the topic of foam planes, they were mostly the cheap 2 dollar planes you get at hobby lobby. However the two planes that beat me were both made of balsa wood, again from sets from hobby lobby, though one was from online, but it wasn't made for SO, and appeared to be an older model, covered in tissue paper. The other had a small wing chord and didn't take advantage of the full 40 cm wingspan, with a wingspan of only about 30 cm. another boy cam in with the same FAI kit as me, but didn't know how to fly it at all. He wound his plane to only 100 winds, and didn't trim it well. His plane just dropped like a rock. The winning plane got a time of about 15 seconds, the second place 11 seconds, and i got about 9 or 10 seconds . Bear in mind that this was school tryouts. NOT competition !

i think that's the zeigler kit. I made one of those for fun and it came out really light. When the the MS team i help out at made the zeigler kit they weighed about 7.5 grams.

from my very limited experience with WS:
If you plane was 11 grams it's going to have diffuculty flying. the ligher the planes the better,
your first plane you every make should be under 9grms so it can have normal flying capabilities.
Was the motor stick securly connected to the Tail boom. I thought mine was, but minor adjustments not visible to the human eye proved otherwise. I glued a stick across the gap to make it more stable, but still allowed for adjustments.
Check the angle of the Tailboom
Check the angle of attack of the plane

this question would actually be answered more thourouly on the other thread as it is a flying problem and not a comparing kits question.

okay... i will copy it into the other thread

Excellent topic. If you guys do proceed, I wish you success. Git It Wright made some very important points. Unless you have access to large quantities of good balsa, you may want to limit your efforts to making plans and instructions, instead of full blown kits.

I don't know if this will help or not, but I'll share our experiences, mostly from the point of view of a prospective customer.

First year experience was 4 years ago. My oldest son built the two planes from the Freedom Flights kit for B division (2005). The planes flew well. Covering with tissue was an adventure, but we learned a lot.

2nd year was BLG with my youngest. He was in 6th grade. We got the Freedom Flights glider kits. Building was an adventure, especially the wing tip lamination (yogurt lids worked best). One good glider was completed, another was a crazy thing that flew decent, but not consistent. Before regionals, we needed a better glider, so I just drew up wing plans to the specs, but with angled tips instead of the circular ones. The difference was wings were easier to make than FF wings. The kid did a nice job, and the glider actually flew a bit longer than the FF glider, despite being 2.8 grams.

3rd year, we just started with what we had the year before, then with the wing span increase, just drew up new plans. We tried fuse changes to try the needle nose thing. Worked well. By this time, all wings and stabs were just drawn up and built, using the specs from the rules. I know some teams went high tech with 2 at States using wing tip dihedral and tip fences. Our much simpler glider with full wing dihedral (much easier to construct for MS kids) lucked out and won due to supreme guts in launching technique. At a higher site, maybe not.

This year, the kid had a few things going for him. An older brother who had done WS for 4 years, and building experience. All he did was look at his brother's plane, and made a motor stick as close as he could. Second plane had a little stiffer truss on the motor stick, but both were light (<3.5 gr.). Wings started with last years glider design, then he wanted 13 cm cord (13 is his "lucky #) and built wings similar to glider wings, but bigger in size. Planes all now use built in motor stick/tail boom angle and post/socket on wing and stab. Worked well enough. He can now cover with mylar much better than I can.

I guess the bottom line is, all of these designs worked well with good construction. All of the ones we came up with are relatively easy to build. Any team with a coach/mentor that has some experience can do this, though most teams that I see continue to buy kits of some kind. So I guess I see your idea being targeted at the teams without mentoring. You would provide the mentoring, design, and maybe some components, provided that you can put them in your package and not charge too much more than they would cost elsewhere. One thing that remains is, how do you get in contact with those teams so they know about your services?

Sorry, but just had another thought. The motor stick and bending seem to be a big problem for many teams. If you guys figure out how to provide a light weight motor stick that doesn't bend, I think a lot of teams could use it. We have experimented with trussed sticks (mostly), just large wood that is low density, and tapered solid sticks, some with carved areas to lighten them. Just a thought.

GitItWright wrote:Straws-

Those tissue straws are tough to make in production. I came across a box of coffee stirrer that are very nice. Ont your average large diameter ones. I took info off the box and here it is...


Good Luck

I assume we're talking about the time consuming task of making paper tubes for the wing to fuse attachment.
Like many other teams, we hated making paper tubes and looked for something else.

We ended up using "Evergreen" brand Styrene square tubes in the 1/8" size. I think the part number is EVG-252. They are at most hobby shops that carry model train supplies
The inside hole is a little larger than 1/16" and they weigh 0.16g/inch.
Normally we use 2 pieces each 1/4" long for the wing posts and 2 pieces each 1/8" long for the rear stab. This adds around 0.12 to the plane but is a whole lot easier than making the paper tubes.
To keep everything tight but still allow adjustment we either make our wing posts a little larger than 1/16 or just use a tiny amount of rubber cement to hold the wing posts in place during the trimming process. The rubber cement is strong enough to keep the post from moving if it gets bumped but doesn't harden and allows for adjustment later.

We ended up using "Evergreen" brand Styrene square tubes in the 1/8" size. I think the part number is EVG-252. They are at most hobby shops that carry model train supplies
The inside hole is a little larger than 1/16" and they weigh 0.16g/inch.
Normally we use 2 pieces each 1/4" long for the wing posts and 2 pieces each 1/8" long for the rear stab. This adds around 0.12 to the plane but is a whole lot easier than making the paper tubes.
To keep everything tight but still allow adjustment we either make our wing posts a little larger than 1/16 or just use a tiny amount of rubber cement to hold the wing posts in place during the trimming process. The rubber cement is strong enough to keep the post from moving if it gets bumped but doesn't harden and allows for adjustment later.[/quote]

The plastic straws that I found and referred to are probably 50% lighter than the Evergreen Styrene tubes.

Good Luck