Foamy Pusher Gyro - Page 2 - RC Groups
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Dec 25, 2014, 11:59 AM
Registered User
Well done Russ that's a nice Christmas present for all the gyronuts regards
Kevin
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Mar 13, 2017, 02:15 PM
Wyatt Earp

Question about setup


Good Day Rus;

Great design and I'm going to give it a go here in Kingman, AZ! I am new to autogyros and need a little help. Your plans are very clear and well laid out. My question regards what type of servos are used and how they're configured. Do you use metal geared servos, or standard 9g servos? Also, I've seen control heads where both servos are connected to a common axis. Do you mix the controls as you would with a flying wing or v-tail plane? Thanks in advance for your help.

Wyatt,
Kingman, AZ
Mar 13, 2017, 07:22 PM
Registered User
I'm glad you like this design, thanks! The servos we first used on the foamy pusher were regular 9 gram servos. They work just fine, but the gears can get damaged if you have a tip over and knock the head. For this reason we changed over to slightly heaver 14 gram servos with metal gears. We flew a long time with the regular servos, so if you already have them, they will be fine for now. If you are looking for metal gear servos we have used the Turnigy TGY-90S micrfo servos sold by HobbyKing. They are very inexpensive, and have performed well not only on this autogyro , but larger ones as well.

The head on the Foamy Pusher uses one servo to tilt the rotor left and right and is connected to the aileron channel of the receiver. The other servo tilts the rotor forward and backward and is connected to the elevator channel of the receiver. No mixing is used. Yes, another popular rotor head design has both servos mechanically connected where they operate a little differently. An example of this is the HK head used on many model autogyros. (sold by HobbyKing). It is a shortcut instead of having to build the rotor head, as it just bolts onto a spruce stick above the model. That head will also work on the Foamy Pusher, should you want to go that route. Good luck with your build, and let me know if you have any more questions as you go.

Cheers!
Russ
Mar 13, 2017, 08:28 PM
Wyatt Earp

Thank You!


Russ;

Thanks for the quick reply! Guess I was a little dense regarding the servo setup, or more precisely how the pushrods interact with each other. I now see that as the head pivots in both planes the pushrods will just go along for the ride!! Thanks again for your help Russ and I'll keep you posted on my progress.

Wyatt
Kingman, AZ
Mar 15, 2017, 06:00 PM
Wyatt Earp

Just A Couple More Questions.


HI Russ;

Well, I'm on the home stretch and just have a couple of questions before I finish up. You mention in the plans that the rotor rotates clockwise. The cross section in the drawing indicates the leading edge of the blade is dropped on the right side. Wouldn't this produce an anti-clockwise rotation and does it really make any difference which way the rotor turns?

Finally, I think I have the mounting position on the servos figured out. One servo arm will operate at right angles to the tower (roll) and the other, parallel to the tower (pitch). Anyway, thanks again for your help and let me know if I'm on the right track!

Thanks,
Wyatt
Mar 15, 2017, 07:39 PM
Registered User
Hi Wyatt,

Good to hear you are progressing so quickly. I think you may have found an error in the side view of the rotor. The rotor on the models we built did turn clockwise when viewed from the top. If you built the rotor the other way around and it rotates counter clockwise, that should not be a problem. We have flown models with rotor directions either way. It will affect the in flight trim settings, but only in the case of trim settings for one rotor direction when the rotor is replaced with one that turns the other way. Since you have no trim settings yet, it won't be a factor for you.

The leading edge with the carbon rod is always turning into the wind as the model moves forward, never the other way around. The drop, or negative pitch angle is present so the rotor will turn, but lift is still generated in autorotation. THE most important thing to observe is rotor speed. It must be turning fast enough for autorotation to be in play, otherwise the model will roll over and fall out of the sky. Luckily, one can hear the difference. If holding the model and walking slowly into the wind, you will hear the change as the rotor speeds up and feel the lifting pull upwards .

Cheers,
Russ
Mar 15, 2017, 09:55 PM
Wyatt Earp

Thanks Again


Good evening Russ and thanks again for your prompt response. I'll build the rotor so that the shim is on the right-hand side of the cross section (leading edge facing left). Can't wait to give your design a try! Will keep you advised on the build and flight tests.

Good Night,
Wyatt ;-)
Mar 16, 2017, 12:00 PM
Registered User
Hi Wyatt,

When you are done building, before you put the rotor in place, you will want to hang the model by the rotor shaft using kite string or fishing line. Then slowly advance the throttle and see if the model rotates on the string or just swings up in a straight line. If it rotates, you will want to move the motor on its mount right or left a little to compensate. Don't be tempted to angle the motor with right or left thrust. You want the thrust line to be straight back at zero degrees in all planes. The rotation is caused by prop blast hitting the tail, and moving the motor a little bit will allow the model to swing forward when you advance the throttle which is what you want to happen. Otherwise, as you change throttle settings a turning force will be generated in flight.

I hope this helps you get off to a good start on your first flights.

Cheers,
Russ
Mar 19, 2017, 06:59 PM
The 1st Sofaman
Sofaman NJ's Avatar
Great job on that little pusher! Flies great!

Congrats!

Dave