Flight B/C

[bjt4888]

Thanks for all the info. I am currently using rubber from J&H. When I am stretching it I notice the tension is very high at around 4x its original length, and I am afraid to go further. I have also read your guide for rubber motors. I found it very helpful, but I do not understand how the motor can possibly get to 4.7k winds when we can barely even get to 1600. What else am I doing wrong here?

Danx,

Sorry missed your rubber stretch question. Yes, believe it or not, you can and should stretch to 5x or 6x a loop relaxed length for winding. Only one batch of Tan Super Sport in recent years has been “stiff” and could only be stretched without breaking 4x on first use, that was May 2018 rubber. Strangely, this vintage of rubber was very good for the helicopter event. We usually stretch 5x on the first use and 6x on uses thereafter. This stretch is necessary if you want to wind to 95% of breaking turns. Once broken in, the rubber shouldn’t break till its stretched almost 10x (properly tied knot required too).

Brian T

[danxmemes]

Danx,
Read the document carefully. You’ll see that, for that year the rubber motors were around .060” wide rubber strip and the example motor was 26” long. A typical motor for this year will be .094” wide strip and 15” long loop. Using the equation in the document, you will see that maximum turns for a 15” loop of .094” (reallly this is .0624 g/inch more exactly) is 1,963 turns. As the document explains, these are turns required to break a motor. So a reasonable target for turns for a first use of a motor would be 1,500 to 1,600, or 100 winder turns using a 15:1 winder. Note that as a motor is “broken in” by using several times it improves in energy storage and is permanently stretches slightly and takes more turns. My teams shoot for 82% of breaking turns for the first use and up to 90% (or 95%) on the third use. Best use is usually the third or fourth if winding like this.

Brian T

Brian,

I see how it works now, I calculated it with its full length instead of its looped length. Thanks!!

Daniel

[bjt4888]

Danx,

Sounds good. Keep up the good work and ask any questions that come up.

Brian T

[Herbster03]

I'm back again with yet another question...
What are your opinions on Freedom Flight? I was deciding between J&H's Stinger or the 2023 FF kit, and both are around the same cost. I'm so confused right now and I've done a ton of research+spent a lot of time on this. I still have not come to a conclusion and I'm running out of time.. Thoughts?... Any help would be much appreciated. (context: I have experience w/ gluing delicate pieces from bridge, I'm patient, but I'm not sure if I can build FF without screwing up. I don't want to waste 79$, but J&H is so expensive...)

Hey Cat,

I did Wright Stuff for 5 consecutive years and have made Freedom Flight, J&H Aerospace, and custom planes. I believe that Freedom Flight is a better kit for those that are not that well versed in building planes yet. While both kits will provide certain templates, the overall construction of Freedom Flights is slightly easier to build and is generally easier to calibrate for those that might not have too much experience. J&H in your context might be a a better late season build. I personally think that J&H usually has an on-par or even better design than Freedom Flight but it is much harder to calibrate, especially is you don't have a lot of gym time.

In terms of budget and costs for flying events, especially for planes, it just depends on how serious you want to invest. Spending a lot of money is not necessary and I have seen teams that succeed without having to do so, but for anyone that wants to get competitive but doesn't have the knowledge to make their own design, a kit from either Freedom Flight or J&H is a very good investment. I would personally buy Freedom Flight over J&H if I was on a tight budget and in your position.

When building, think of ways to minimize any mistakes. For example, Freedom Flight will provide you with a paper template. DO NOT USE IT IMMEDIATELY. If possible, laminate it, either through your school or wherever possible, or cover the surface with clear boxing tape. Constructing your plane without this will result in pieces ruining the template and possibly ruining your build when you are gluing if you are not careful. One thing to do to reduce the amount of CA you use is to pour a small amount of CA out on another surface, I used printer paper sized lamination sheets, and then use something like a small metal nail to apply your CA. Additionally, use masking tape to secure your parts onto your template! This will allow it to set without the worry of shifting. If you are short on time, considering getting Insta-Set. It will pretty much immediately set the glue (however do not consider using it for builds like bridges for it will weaken your structure).

I also personally paid for everything out of pocket and I do admit that the amount of money that I spent on Science Olympiad became scary. If your budget does increase or you are more willing to put in money in the future, keep in mind that there are a lot of variables that can be invested in for flying events. For example, similar to getting things like specialized balsa for structure build events, you can get custom sized cuts of rubber. Also, I do not suggest using rubber that is getting old. As rubber sits, it will naturally deteriorate and become more brittle, stretching less, holding less torque and winds, as well as being more probable to snap during competition. This though, is usually not a concern unless you are actively competing for the top tiimes. Additionally, if you need extra parts, such as wing ribs, you can always buy extra from both Freedom Flight and J&H. They will sell it to you individually even if they are not listed on their website. Just give them a call and they have usually figured out a way to make it work. Thing like a torque meeting found from Freedom Flight will be a huge help in replicating flights and keeping things consistent. Even if you do not get one, don't try to wind your motors while they are still attached to your plane. Instead, you could use something like a small board with a nail on it to hold your motor so that you can finish winding and then place it on afterwards.

While many forms of communication within the community have died down in the past couple of years, they are still a great way to ask questions besides these forum. Many experienced alumni are still active on both the official and non-official discord servers so feel free to reach out there!

- Herbert Edmonds

[bjt4888]

Herbert,

Lots of good info. Good job as a recent SO alum to help with the forums.

Only disagreement is about rubber degrading as it ages. I lost an eBay bid last week for a half pound of March 2002 Tan II. I dropped out after the bidding topped $200.00. Best vintage ever made is May 1999. It goes for about $200 for a quarter pound.

A number of indoor flying enthusiasts have records of energy storage tests for all important rubber batches going back to the 1970’s.

Luckily, none of these special batches of rubber are necessary for Science Olympiad. My teams generally get good results from current batch of Tan Super Sport though.

Keep up the good input,

Brian T

[Herbster03]

Herbert,

Lots of good info. Good job as a recent SO alum to help with the forums.

Only disagreement is about rubber degrading as it ages. I lost an eBay bid last week for a half pound of March 2002 Tan II. I dropped out after the bidding topped $200.00. Best vintage ever made is May 1999. It goes for about $200 for a quarter pound.

A number of indoor flying enthusiasts have records of energy storage tests for all important rubber batches going back to the 1970’s.

Luckily, none of these special batches of rubber are necessary for Science Olympiad. My teams generally get good results from current batch of Tan Super Sport though.

Keep up the good input,

Brian T

Hi Brian,

I have heard of such rubber but never actually know anyone that went out of their way to use it. I also have heard stories from back in the day of traveling to other countries for higher quality rubber batches and then cutting it to size. It is very fascinating to know that it still exists out there and that it performs so well even after all this time!

To clarify for others, I am referencing the rubber from what I used and experienced that was Tan Super Sport from FAI. It did not really matter in terms of within the season (and I usually used most of what I ordered anyways) but after that, I usually did not touch it again. I think the lower performance of this rubber is only seriously noticeable around 2 years after. This might not be exactly due to degradation, but there was performance issues that I personally noticed.

As another bit of advice for those that are new to flying events, rubber motors usually perform the best on their 2-4 uses. So, if you are going into competition, I suggest you make new motors to whatever length or weight you are aiming for and then wind them once like you would for a flight. Then, just simply unwind them and store them for your competition flights. Lubricant is also very helpful to reduce knots within the motor and to get more winds in. Don't add it before check-in as depending on what lubricant you use, it might increase the weight of your motors. The rules specifically say that adding it afterwards during the flight time is allowed so do it then if your motor(s) are cutting it close to the 2 g limit.

- Herbert Edmonds

[danxmemes]

Hi, I was reading your post about lubricant adding weight. For your first windup, would you add lubricant for it? If you do, the rubber gets heavier? But if you don't wouldn't there be potential breakage? How can you fully optimize it for competition?

[jander14indoor]

Busy forum already!
Some comments.

See the SO resource page for flight, there is a long document there about glue I wrote a number of years ago, it still applies. A key with CA has already been mentioned. DON'T apply directly from the bottle to your plane, put a drop somewhere you won't set your hand and transfer SMALL amounts to each joint. You can build a whole plane from one or two small drops of glue. Frankly if you can detect weight gain more than a couple hundredths on a wing, you are using too much.

Fresh glue, why it is important. As CA ages, it slowly sets (sometimes not so slow). This causes it to thicken and requires you to use more (adding unnecessary weight, always a bad idea) to get good joints. If you are using accelerator, make sure you store it separately from the CA. This is a key reason glue thickens early.

Which kit. Frankly, if you are new, don't sweat it. Your first job is to learn how to build, then how to fly. If you are serious about winning, this first kit will be far from the only plane you build. If you just want to do well, frankly, simply learning how to build and fly ANY reasonable design will win all but the most competitive regionals!

Rubber lube, it doesn't take much, NEVER wind without it. You'll damage the motor immediately with any serious winds and it will break far short of that calculators predictions. Again, it doesn't take much, apply and wipe off excess.

Rubber aging. It all depends on storage conditions. Let it get hot, expose to sunlight, expose to ozone, it can deteriorate VERY fast, dead within a season. Keep it in the dark, keep it cool (some people actually freeze their motors to store for long periods), keep it from excess sunlight and it will last years.

Rubber energy storage, or 'magic' rubber. Yes, there are vintages of unusually good rubber but only 10 - 20% better. Frankly, you don't need it to do well in SO. The good news is there is very little BAD rubber (as long as you are using FAI TAN Super Sport, this wasn't always true, but has been for a number of years now). Your first focus must be on building straight and light, and then on trimming to optimise what you have. That's how you get from your plane crashing all the time to 2+ minute flights. Not magic rubber. That super rubber is really only valuable to a limited number of flyers who are already getting 90-100% of a planes capability and in VERY competitive contests. Like world championships or record attempts.

Jeff Anderson
Livonia, MI

[pumptato-cat]

Thank you so much for the post, jander14indoor!! Very helpful :D
Do you know of any local stores with fresh CA? Does brand matter much?
ahhh ignore my first question, i completely missed your earlier post D:

[jander14indoor]

Good hobby shops with significant business will generally have fresh CA. Ask them. You can also check freshness, even medium thick CA is VERY watery when fresh. Most bottles are at least translucent, tip it over and see how it moves in the bottle.

Unless you live in SE Michigan, I can't make any recommendations. If you do, try Prop Shop in Warren or Nankin Hobby in Farmington.

Jeff Anderson
Livonia, MI