Wright Stuff C

[bjt4888]

Polar,

This would be up to the event supervisor. When I supervise at local invitationals, an open “practice period” does not involve any type of check in of students.

Regional, State and National Championships May be more restrictive.

This being said, I coach my students so that they can wind motors on the torque meter and transfer to the airplane by themselves. You shouldn’t really need a partner for practice. Of course, a partner is helpful for getting the pre flight bonus and for winding and launching two flights in the 8+3 minutes.

Brian T

[JasperKota]

We have some dutch roll on the FFM model. Do you suggest building our own new vertical fin or is there a simple way to add a little to the FFM model? When you say "does not take much" can we just add a little balsa fin to the to or maybe a small stiff piece of paper?

I added a small rectangular 1/16th width balsa fin along the carbon fiber vertical edge of the rudder from the kit, and it fixed my dutch roll. Be careful while you're gluing it on though and make sure it's straight.

[coachchuckaahs]

We have some dutch roll on the FFM model. Do you suggest building our own new vertical fin or is there a simple way to add a little to the FFM model? When you say "does not take much" can we just add a little balsa fin to the to or maybe a small stiff piece of paper?

I added a small rectangular 1/16th width balsa fin along the carbon fiber vertical edge of the rudder from the kit, and it fixed my dutch roll. Be careful while you're gluing it on though and make sure it's straight.

Thank you for reporting back. Glad it worked (though I was sure it would)

Coach Chuck

[Rossyspsce]

After cutting down and sanding the flared prop, I began testing. I experienced flight characteristics similar to that of using just a standard 24cm symmetrical ikara prop. Flight time, peak height, winds after, etc were all the same/similar, with the only noticeable difference being the recovery of the flared prop seems to be much quicker to right itself. Below I have listed my current set up:
Weight of prop: 2.44g
Weight of plane: 5.93g
Combined weight: 8.40g
Motorstick length: 15.25 in
Rubber width: .094 in
Rubber weight: 2.35-2.52g
Winds: ~1800
Launch torque: .75-1, not sure what the units are, just calibrated to my own needs
Any help or suggestions would be greatly appreciated to help me hedge the peak height or increase flight duration.

[JasperKota]

Thank you for reporting back. Glad it worked (though I was sure it would)

Coach Chuck

Thank you for the immense amount of advice you've been giving to everyone! Regionals ended up going very well for me (although at that time I hadn't fixed the dutch roll), but achieving consistency has been a bit frustrating.

During my first run at regionals, with 1350 winds rather than my usual 1650, it climbed lower than usual, maybe only 2/3 the ceiling height (approx. 22 feet ceiling) as opposed to very close to touching ceiling beams, but achieved the longest flight time I've ever had by ~25 seconds. Unfortunately, air vents were on and during my second run I chose to stand at a different spot, so although I wound around 1600 and it climbed higher, my flight time was about 40 seconds worse than the first (which I think was due to the vents).

The puzzling thing is, using the same exact number of winds as the first run, with the same plane without modifications, the times I achieved were drastically (around a minute) lower than that one run. Even with more winds and climb I haven't gotten close to that time. I've since given up on trying to get there again with the same settings and have been focusing on matching prop with thicker rubber (all my flights had been coming down with a large number of winds still left) and fixed the dutch roll (although without it it's been climbing faster since there's not that occasional stall).

This being said, I coach my students so that they can wind motors on the torque meter and transfer to the airplane by themselves. You shouldn’t really need a partner for practice. Of course, a partner is helpful for getting the pre flight bonus and for winding and launching two flights in the 8+3 minutes.

Is there some sort of stand built to hold the plane on while putting the motor on without a partner? Or do they just take the entire motor off the torque meter after winding, and while holding the propeller still with one hand, use the other to hook it onto the prop and then the rear hook? I've been limited in practicing partially because I've been needing someone to hold the plane for me while I transfer the motor.

[coachchuckaahs]

Wind on a stooge.

Pull rubber o ring off the winder, leave it on the torque meter.

Grab plane by nose, fingers around prop to keep it from turning, with other hand (I have plane/prop in left hand) hook rubber to prop.

Now use right hands to transfer tail hook end of rubber

Coach Chuck

[Rossyspsce]

After cutting down and sanding the flared prop, I began testing. I experienced flight characteristics similar to that of using just a standard 24cm symmetrical ikara prop. Flight time, peak height, winds after, etc were all the same/similar, with the only noticeable difference being the recovery of the flared prop seems to be much quicker to right itself. Below I have listed my current set up:
Weight of prop: 2.44g
Weight of plane: 5.93g
Combined weight: 8.40g
Motorstick length: 15.25 in
Rubber width: .094 in
Rubber weight: 2.35-2.52g
Winds: ~1800
Launch torque: .75-1, not sure what the units are, just calibrated to my own needs
Any help or suggestions would be greatly appreciated to help me hedge the peak height or increase flight duration.

Sorry for quoting myself but is anyone able to help with this before it gets lost in the mass of other text?

[CrayolaCrayon]

After cutting down and sanding the flared prop, I began testing. I experienced flight characteristics similar to that of using just a standard 24cm symmetrical ikara prop. Flight time, peak height, winds after, etc were all the same/similar, with the only noticeable difference being the recovery of the flared prop seems to be much quicker to right itself. Below I have listed my current set up:
Weight of prop: 2.44g
Weight of plane: 5.93g
Combined weight: 8.40g
Motorstick length: 15.25 in
Rubber width: .094 in
Rubber weight: 2.35-2.52g
Winds: ~1800
Launch torque: .75-1, not sure what the units are, just calibrated to my own needs
Any help or suggestions would be greatly appreciated to help me hedge the peak height or increase flight duration.

Sorry for quoting myself but is anyone able to help with this before it gets lost in the mass of other text?

How high is your venue? .75 is a pretty big launch torque.

[Rossyspsce]

After cutting down and sanding the flared prop, I began testing. I experienced flight characteristics similar to that of using just a standard 24cm symmetrical ikara prop. Flight time, peak height, winds after, etc were all the same/similar, with the only noticeable difference being the recovery of the flared prop seems to be much quicker to right itself. Below I have listed my current set up:
Weight of prop: 2.44g
Weight of plane: 5.93g
Combined weight: 8.40g
Motorstick length: 15.25 in
Rubber width: .094 in
Rubber weight: 2.35-2.52g
Winds: ~1800
Launch torque: .75-1, not sure what the units are, just calibrated to my own needs
Any help or suggestions would be greatly appreciated to help me hedge the peak height or increase flight duration.

Sorry for quoting myself but is anyone able to help with this before it gets lost in the mass of other text?

How high is your venue? .75 is a pretty big launch torque.

20ish feet is my regionals and about the same height for where I've been practicing for it. But I did a lot of testing in 50 feet and it was similar to a standard sym ikara prop

[bjt4888]

Rossyspace,

Good job reporting data. I don’t see that you mentioned the pitch of your flaring propeller. If the flaring propeller is performing similar to the 24 cm symmetrical propeller, you may need to increase pitch angle. We usually start by having three propellers of different pitches ready for testing and two to three different densities of rubber (more pitch usually requires more rubber density). Typical pitch/ diameter ratios to test would be in the 1.4 to 1.7 range for WS.

Also, if flaring propeller performance is similar to the symmetrical prop, maybe try sanding thinner to get more pronounced flare.

Also, 1,800 turns is only about 70% of breaking turns for a 20” loop of .094” rubber (around 2.5 grams). Get max turns up to 80 or 85% for better duration (will probably require more backoff turns and slightly lower launch torque at this turn count).

Good luck,

Brian T