Monotwirl Electric Autogyro - Page 5 - RC Groups
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Feb 12, 2010, 08:32 AM
Keep it simple
alfoot's Avatar

Your wish is my command All of the Monotwirl movies are nowon the thread in Youtube. It was so frustrating when Putfile caved in, I must have about 100 movies that need re-uploading to Youtube now.

Here are a couple of movies of the micro ( 1/3 size) version of the Monotwirl that I haven't previously posted here:-

Micromonotwirl 14 Oct 07 (2 min 2 sec)

Indoor movie here:-
Micro Monotwirl Autogyro Indoors 13 Oct 07 (2 min 28 sec)

Last edited by alfoot; Feb 12, 2010 at 08:39 AM.
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Feb 13, 2010, 06:06 AM
Registered User
Thanks for doing that Al, your effort is much appreciated.
With your production rate, you are set to replace the fine gentleman who ran Gyronuts for a while with the plans, tips & info that you make available.
I'll be back!
Feb 13, 2010, 08:03 AM
Aerial Images of Texas
tashley's Avatar
Yes, thanks Al.
Mar 08, 2010, 08:47 PM
Sopwith Camel's Cousin
Originally Posted by alfoot
...Here's my latest version of this aircraft - the MiniMonoTwirl, with a 12 inch diameter rotor (about 50% of the original).

I've done a micro version powered by a 7mm pager which weighed 10 grams, but this one has a 5 gram brushless motor, Musclewire servos for rudder and elevator and a 3.7 gram servo for lateral rotor tilt. Microinvent receiver and a 2 cell 250mAh battery. Total weight 50 grams.
I know it has been awhile, but I was wondering how to do a scaledown of
the monotwirl plans to the mini and micro versions.
From the photos (post #32), the rotor likes the same 1.5 inch wide 3mm depron blades attached in the same way. The only difference is that as
you make the smaller versions, the blades get shorter:
~6 inches each for the mini version, ? for the micro version.

The weights for the mini and micro versions are mentioned above,
as is the length (~50% of the original) of the mini version.
I am wondering what the length of the micro version is.

Last edited by flying-llama; Mar 08, 2010 at 08:57 PM.
Mar 09, 2010, 02:28 AM
Keep it simple
alfoot's Avatar

The MicroMonotwirl is 22.5 cm long from the back of the rudder to the front of the fuselage. I used 1 inch chord rotor blades with a rotor diameter of 8 1/4 inches. As the lift/drag was not good, I also used stub wings to get better performance. Everything was made from 2mm depron.

Mar 09, 2010, 05:28 PM
Sopwith Camel's Cousin
Originally Posted by alfoot
... I also used stub wings to get better performance. ...
Thanks for the size information.
I am new to autogyros, so I may use stub wings as "training gear"
for any autogyro that I build.

One thing that I am learning from reading about auto-gyros is that when scaling up or down,
not only does one need to worry about scaling lengths, areas (wing & disc loading) and weights,
one also needs to worry about scaling the amount of flexing done by the rotor blades.
Last edited by flying-llama; Mar 09, 2010 at 05:44 PM.
Jul 22, 2010, 06:25 PM

Monotwirl plan

Originally Posted by SafeLandings
Hi All,
Does anyone know where the Monotwirl plan can be obtained from?
It looks a great little design and flies well

Regards Rich
As i could not find a monotwirl plan download, i am using the twirl plan for profiles and scale and then scaling up to 40 inch length using tileprint software.I am going to build it as two sides as this gives a proper fuselage with 6mm inner platform spine and formers with 3mm sides. I will hide everything inside but this method gives more variation and additions to the design. The cockpit will house the two servos for elevator and rudder covered with a platform with pilot. All other areas of the monotwirl will be hand scaled and added to the drawing as we go.
I feel enthusiastic and excited about this new project because the original twirl flew so well and i had a lot of fun with it, just have to try the other one, but bigger. I will keep everyone posted with photo's as we progress and one day the eventful first flight. Watch this space...
Jul 23, 2010, 12:40 AM
Registered User
The plans for the MonoTwirl can be found at Post 54 in this thread.
Jul 23, 2010, 06:03 AM
Registered User
flying scrap's Avatar
hi al, just want to say thanks for the plans, it flies great
i did modify it a bit ok quite alot really
as i only had enough depron for 2 sets of rotors and a cut down
tail i used carbon tubes for the rest
because my field is very rough i broke the blades alot on landings
so i changed them for a couple of rotorshape blades
that worked a treat
heres a couple of photos of my efforts

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Jul 24, 2010, 01:00 PM
Registered User

maiden flight.

It was flying nice and straight from the hand launch until the prop saver band came off! and then autogyroed down. I'm really pleased with the model. thanks for the plan.

Now to work out a better prop. mount and strengthen the landing gear.

Jul 24, 2010, 02:13 PM
Registered User
Jockadopolus's Avatar
Videos Steve?
Jul 24, 2010, 02:32 PM
Registered User
not yet, Joe. No cameraman!
Jul 25, 2010, 03:46 PM
Registered User
So here is some video of two very short "flights". Any tips on how to make the longer greatfully received.

MonoTwirl250710_0002.wmv (0 min 49 sec)
Jul 26, 2010, 03:57 AM
It's all in the Blades!
SafeLandings's Avatar
I'm sure AL will be able to point you in the right direction, to me it looks tail heavy?

Jul 26, 2010, 01:51 PM
Keep it simple
alfoot's Avatar

The launch technique seemed pretty good.

As Rich says, it is worth checking the CG.

You said that it went off straight the first time you tried it (before the prop came off).

For the launches that you filmed, was it exactly into wind? It looked from the movie that it yawed off left pretty much instantly, and you would need to be quick to get it back into wind using the rudder. Was the rotor trimmed level?

Something you could try would be to hold it into wind like you did in the movie, with the power off, and move the rotor control to feel what this control is doing. You may also be able to feel if the autogyro wants to tilt left, and, if so, pre-apply some trim. Repeat the exercise with the motor at take-off power and repeat, so that it feels as if it will stay level when you launch.

A final thought might be that the rotor blades are not flapping enough. If you used UHU Por to glue the blades then they should flex enough.

Hope this helps,


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