Hey All, just wanted to post a quick video my friend shot of my Twirl. Sorry, no takeoff or landing. Hopefully I'll get some pics up soon too. My version is balsa with a full fuselage. Thanks Al Foot for handling the geometry! This thing is a Hoot!

http://www.youtube.com/watch?v=nY4wX...HgZ7njscy8XlzY

Shafferama, I really enjoyed your youtube video. I am not a fan of foam - much prefer balsa. I did the Twirl pdf file for Al which is posted on page 5 of this thread. Very interested in photos of your balsa Twirl. Would like to create a Cad file for a balsa Twirl and your photos would help out a lot. Thank you.
Gene

Originally Posted by rchopper56

Shafferama, I really enjoyed your youtube video. I am not a fan of foam - much prefer balsa. I did the Twirl pdf file for Al which is posted on page 5 of this thread. Very interested in photos of your balsa Twirl. Would like to create a Cad file for a balsa Twirl and your photos would help out a lot. Thank you.
Gene

Glad you enjoyed the video! Here are some photos. I really tried to do this great design justice. Thank you Mr. Foot!

Specification:
AUW-8.5oz
Motor-HURC 2712-17
Battery-2s 800 or 1000mah
Prop-APC 8x3.8SF
ESC-15A
Flight time-15-18min.

Features include- Spacious forward electronics bay, riveted leather battery hatch, removable motor cowling...all hatches held fast with magnetic latches! Genuine leather cockpit combing and full instrumentation package! Powered by a robust Lycombing 0-360 four cylinder reciprocating aircraft engine! Hammered aluminum air scoop and functioning internally sprung landing gear! Still need to make a pilot.

Wow, Wonderful detailing and a heck of a nice build. I broke one of the blades while storing away for winter. After seeing your's ...I'm going balsa. Thanks for sharing..... and the motivation to shake the dust off with interest again!

Its very nice to see some one modify a great design in such a different way.
My complements
Happy Landings
Chris...............

Shafferama, Thanks for the photos. It's not what I expected but it sure is neet. Now I have got to put on my thinking hat!
Gene

Thanks for the kind words guys.

Originally Posted by Cr@sh

Wow, Wonderful detailing and a heck of a nice build. I broke one of the blades while storing away for winter. After seeing your's ...I'm going balsa. Thanks for sharing..... and the motivation to shake the dust off with interest again!

I hope you'll give a balsa version a go. I love flying this thing. It really is unlike an airplane. With rchopper56s' excellent PDF it was pretty easy to come up with something structurally sound and simple to build. I Clark-Y d the wing-pylons but am convinced that was unnecessary.

Originally Posted by britinoz

Its very nice to see some one modify a great design in such a different way.
My complements
Happy Landings
Chris...............

Thank you sir! Happy landings indeed. This Twirl is ideal for STOL, small field flying, and near vertical landings!

Originally Posted by rchopper56

Shafferama, Thanks for the photos. It's not what I expected but it sure is neet. Now I have got to put on my thinking hat!
Gene

You did a bang up job on the PDF for the foam version! It was very useful and key to my build. I'm sure you're up to the task of CADing a balsa version!

I was wondering why you did not flip servos around and have linkage exiting out the back ,inside tail cage. You did such a great design with it like from vintage error that the horn kinda looks out place....sorry, I shouldn't even say that when I couldn't come close to your skills with designing..... I really admire the fuse and nose untill you hit the black servo...how about paint and wood grain.....just an idea I might try.....be cool if I could take carbon rods and paint like bamboo poles .dubro micro's linkage works just the same . I'm impressed with the vintage look sir ...again "Fine work" !

Hello!

Nice video!

Excellent model!

I like that nice and airy fuselage .
What coverfilm are you using?

I like wery much yours blade construction.
Can you test little more and move that blades upper part like some 50% and or middle off airfoil?

Long a go i test some rotorblade with 50% upperpart and it just get some nice lift.
So,hummmm... KF-airfoil it is. Stange but nice effect.

It work nice and i dont know if its that KF-airfoil or if it is just that day that have those nice moments..

Keep up the good work!

Best regards from Finland

Kari

Originally Posted by shafferama

Glad you enjoyed the video! Here are some photos. I really tried to do this great design justice. Thank you Mr. Foot!

Specification:
AUW-8.5oz
Motor-HURC 2712-17
Battery-2s 800 or 1000mah
Prop-APC 8x3.8SF
ESC-15A
Flight time-15-18min.

Features include- Spacious forward electronics bay, riveted leather battery hatch, removable motor cowling...all hatches held fast with magnetic latches! Genuine leather cockpit combing and full instrumentation package! Powered by a robust Lycombing 0-360 four cylinder reciprocating aircraft engine! Hammered aluminum air scoop and functioning internally sprung landing gear! Still need to make a pilot.

Originally Posted by Cr@sh

I was wondering why you did not flip servos around and have linkage exiting out the back ,inside tail cage. You did such a great design with it like from vintage error that the horn kinda looks out place....sorry, I shouldn't even say that when I couldn't come close to your skills with designing..... I really admire the fuse and nose untill you hit the black servo...how about paint and wood grain.....just an idea I might try.....be cool if I could take carbon rods and paint like bamboo poles .dubro micro's linkage works just the same . I'm impressed with the vintage look sir ...again "Fine work" !

Awwww, you're totally right about the servos. I put them on the outside primarily for ease of access (it's a little tight inside the fuse), but they do look out of place. I like your wood grain idea. I was thinking of boxing in the servos with some 1/32 sheet and painting the servo arms to look like wood. Thanks again!

Originally Posted by Autorotator

Hello!

Nice video!

Excellent model!

I like that nice and airy fuselage .
What coverfilm are you using?

I like wery much yours blade construction.
Can you test little more and move that blades upper part like some 50% and or middle off airfoil?

Long a go i test some rotorblade with 50% upperpart and it just get some nice lift.
So,hummmm... KF-airfoil it is. Stange but nice effect.

It work nice and i dont know if its that KF-airfoil or if it is just that day that have those nice moments..

Keep up the good work!

Best regards from Finland

Kari

Thanks for the kind words Kari. The covering is simply tracing paper with butyrate dope. Yeah the KF foil is slightly strange phenomenon. I've thought of building another set of rotors to experiment with, and may at some point, but this Twirl flys so well as is that I almost don't want to mess with it!

I have had my Twirl for about a year, but have suffered from foam breakages, caused it is suspected by the depron foam I have access to, being brittle. Nearly every flight a blade would collapse or even shed its self from the rotor. I have just test flown modified rotors with huge success, the Twirl is definitely flying ‘crisper’ than previously with the paper reinforced blades, and everything has come home in one piece!!!!

I have reinforced the blades with ½ diameter bamboo BBQ skewer. I sanded one side of the bamboo flat, length wise, and it is as near as matches the 3mm of the depron, I then glued the bamboo flat to the edge of the foam blade, replacing the paper reinforcing. The blade was then assembled exactly the same as if using the paper reinforcing blades. The result is a substantially stronger blade that still flexes a little in flight, similar to the paper reinforced blades. The cost of the modification is also minimal, the bamboo skewers are $2.50 for a packet of a couple of hundred from the supermarket.

I have included a couple of photos, to better explain what I have done. I have yet to paint the blades, wanting to have a test flight before doing that. Even if you have better quality depron than I do, this modification is worth considering as the chances of hanger damage to the blades is reduced, the blades are just so much stronger.

Originally Posted by davidbegg

I have had my Twirl for about a year, but have suffered from foam breakages, caused it is suspected by the depron foam I have access to, being brittle. Nearly every flight a blade would collapse or even shed its self from the rotor. I have just test flown modified rotors with huge success, the Twirl is definitely flying ‘crisper’ than previously with the paper reinforced blades, and everything has come home in one piece!!!!

I have reinforced the blades with ½ diameter bamboo BBQ skewer. I sanded one side of the bamboo flat, length wise, and it is as near as matches the 3mm of the depron, I then glued the bamboo flat to the edge of the foam blade, replacing the paper reinforcing. The blade was then assembled exactly the same as if using the paper reinforcing blades. The result is a substantially stronger blade that still flexes a little in flight, similar to the paper reinforced blades. The cost of the modification is also minimal, the bamboo skewers are $2.50 for a packet of a couple of hundred from the supermarket.

I have included a couple of photos, to better explain what I have done. I have yet to paint the blades, wanting to have a test flight before doing that. Even if you have better quality depron than I do, this modification is worth considering as the chances of hanger damage to the blades is reduced, the blades are just so much stronger.

I have found the bamboo BBQ skewer to be invaluable in foam construction. Good Mod!

Hi All,

I realize that this thread is c.6 years old already, but I came in late, was very taken by the Twirl concept and am just close to finishing my first example (thank you Al Foot).

I have a couple of questions, the first of which concerns the retention of the rotors to the rotor masts. I have used 2mm carbon rod for the rotor masts and was planning to use wheel collets (as some others have done) but am concerned that the grub screws will soon damage the rotor masts and weaken them.

What other methods of attachment have others used and with what degree of success? I would like the rotors to be easily removable, mainly to reduce the possibility of ‘hangar rash’.

Regards,

Neil

David,great job on the mod , My buddy and myself were able to display ours at a aviation museum event ,. I had to dust mine off and repair a couple of blades as did my pal....he did his nice with carbon rods instead of skewer sticks. I may have to follow his wonderful work. Very stiff with just enough flex and seems lighter than skewers. He mentioned the bead hub and a few other new mod ideas so, I might have to build another like Shafferama or at least a new set of blade rotors. the warmer weather has got me dusting off a few past projects collecting dust...Thank you all for the motivation. a side note , Flying a vapor inside a air & space museum was the coolest thing ever, flew threw folkers,Jenny's,Wright flyer and even landed on wing while suspended. best was the A-10 with a landing on nose.

Originally Posted by neil31

Hi All,

I realize that this thread is c.6 years old already, but I came in late, was very taken by the Twirl concept and am just close to finishing my first example (thank you Al Foot).

I have a couple of questions, the first of which concerns the retention of the rotors to the rotor masts. I have used 2mm carbon rod for the rotor masts and was planning to use wheel collets (as some others have done) but am concerned that the grub screws will soon damage the rotor masts and weaken them.

What other methods of attachment have others used and with what degree of success? I would like the rotors to be easily removable, mainly to reduce the possibility of ‘hangar rash’.

Regards,

Neil

I came into this thread pretty late too Neil and it seems to be pretty dead. I finished my balsa Twirl last September and only posted on it in March. If you're taken by the design now wait 'til you fly it!

Regarding rotor retention, I used 3mm carbon rod rotor masts with 4mm wheel collets. I made up the 1mm difference with a sleeve cut from aluminum tubing. The sleeve distributes the pressure of the grub screw somewhat and prevents crushing the carbon rotor mast. I may at some point replace the carbon with piano wire as the weight gain is negligible and I've found some unsettling wear on the rotor masts from the aluminum rotor bushing. I'd hate to lose a rotor assy in flight! Be sure the collets are tight.

A story about hangar rash...I had just finished my Twirl and was taking it out for a second round of test flights. I had yet to install a main spar between the winglet/mast assemblies; they were glued at the root rib and the struts. I was rushing out the door and banged the Twirl against a railing. When I started my roll out, as soon as the rotors began generating enough lift to ROG the right winglet folded, the left rotor rolled the ship onto it's back and into the ground of course tearing out the entire left assy as well! Resulting in a laminated main spar.