Nationals

[OpticsNerd]

Lol, torque BURNER.

Just... don't use that. Almost no one can do it well other than f1d and other OP flyers. Also, i've tried 3000 winds 0.052"... doesn't last for 3:00.

Try 0.05"

[OpticsNerd]

Lol, torque BURNER.

Just... don't use that. Almost no one can do it well other than f1d and other OP flyers. Also, i've tried 3000 winds 0.052"... doesn't last for 3:00.

Also it depends on the weight and pitch of your propeller. A light propeller will spin faster and so does a propeller with a low pitch.

[Crtomir]

The secret is not "Torque Burner". Tower Heights does not use that. Their planes ascend nicely and then descend very very slowly.

First off, we tried changing the pitch of the standard 15cm Ikara props (trimmed to 13.8cm of course). It turns out that 22 deg. was optimal, which is good because that's what most of the Ikara props are set to originally.

Next, we did extensive testing with different thickness rubber. We found the optimum point, both in terms of number of winds used during flight (# winds initially - # winds left over (yes, we counted them)) and flight time. Because I don't believe in secrets, I will just tell you that the optimal thickness rubber was around 1.4 g/m. We measure rubber thickness not by actual thickness, but by linear density. We cut a 1.1 m length of the stripped rubber and weigh it. Then we take that weight divided by 1.1 m and that is the linear density. Thinner rubber will be less dense than thicker rubber. To give some perspective, standard 1/16" rubber has a linear density of 1.65 g/m.

But that still does not get a super long flight. In a 23-24 ft gym, we were getting flights up to and just over 2 min., but we had to hit the ceiling to do that. Most gyms have rafters, so our kids played it safe and only would get about 1:45 or so. One gym was much higher so they got just over 2 min. at that competition (New Albany). I think that was where Tower Heights got over 3 min..

So, the secret is not the thickness of the rubber. At least that's not the only secret.

The secret is using flared props. The problem is that you can't just buy these. You have to build them yourself. Fortunately, you can purchase Ikara kits for these from Freedom Flight Models: http://www.freedomflightmodels.com/props.php. Flared props stick out more in the front of the prop spar then in the back so when there is a high torque at the beginning of the flight, the props open up to a higher pitch and slow it down so it unwinds slower. Then, as the flight progresses and the torque drops, the prop closes back up and the prop spins faster. It's essentially a variable pitch propeller, but not one they can exclude from competition because there are no moving parts. It works only be the bending of the prop blades under higher torque.

We are still testing this, but the results look good so far.

I don't believe in secrets.

[CMS AC]

What is the design of the propeller blades, and what's the pitch?

Also, if you're comfortable telling me this, what design do you or tower heights use?

[Crtomir]

What is the design of the propeller blades, and what's the pitch?

Also, if you're comfortable telling me this, what design do you or tower heights use?

I have no idea what Tower Heights design is. They don't share their secrets. We only see them in a few competitions. I know they use flared propellers and I'm pretty sure they build those flared props themselves.

We had been using the standard narrow 15 cm Ikara props from Freedom Flight trimmed down to 14 cm and set to a pitch of 22 degrees. Now, we are trying to build our own flared props from the Freedom Flight build your own prop kit. We also set the pitch to 22 degrees. The pitch angle we measured using the pitch gauge from Freedom Flight. I've heard that some set the pitch angle for the flared props to be a little higher to get more of the variable pitch effect.

Tower Heights is so far beyond any of the other teams in Ohio. I wish we know half the stuff they know. All I can say is that their planes are a real beauty to watch. The ascend nicely, but then descend so gracefully and slow. It's amazing to watch. They also don't do any practice flights. Their first and second flights are always official flights. They have everything setup and tuned exactly the way they want. Again, it's just incredible to watch those planes in the air moving so slowly. The secret's gotta be the props.