Time to say thank you

[Peter Germann]

Following first contest flights with Citation and successful initial test flights with Citation Two I have now updated all documents describing the project. A full set of metric drawings including detailed suggestions (in german) on how to build the airplane as well as a Weight & Balance sheet are now available for free download. Formats are Word, .pdf and excel.

https://www.mycloud.ch/s/S000CA232F1DD053AA0362EEE8DE257AE1EF2C533E5

It is important for me to point out here that I understand the "Citation" designation to be an expression of my respect for the big names in our community. Without the contributions of Ted Fancher, Windy Urtnowsky, the Yatsenko brothers, Brett Buck, Igor Burger, Claus Maikis and many others, I would never have been able to design and build a competitive model.

[Brett Buck]

It is important for me to point out here that I understand the "Citation" designation to be an expression of my respect for the big names in our community. Without the contributions of Ted Fancher, Windy Urtnowsky, the Yatsenko brothers, Brett Buck, Igor Burger, Claus Maikis and many others, I would never have been able to design and build a competitive model.

   You are quite welcome, of course, but I am not sure what I did to help (maybe provide a cautionary tale?). That is a rather diverse group you have there and I am glad to be considered among them.

   But, that is such a diverse group that to synthesize such a wide range of information (some of it conflicting) into a single system is really about how *you* did it - so I think you deserve the lion's share of credit.

     Brett

[Ted Fancher]

   You are quite welcome, of course, but I am not sure what I did to help (maybe provide a cautionary tale?). That is a rather diverse group you have there and I am glad to be considered among them.

   But, that is such a diverse group that to synthesize such a wide range of information (some of it conflicting) into a single system is really about how *you* did it - so I think you deserve the lion's share of credit.

     Brett

Ditto!

[frank williams]

Peter .... Your designs and drawings are beautiful as always.

Have you lost patience with the pusher props and gone back to tractors?  Your analysis of the pushers and inline design was excellent with the "My Way" design.  I still think the pushers have something positive to contribute.  The clockwise flyers were successful in the long run.

Thanks for your publication of the model.  ....below .... my version of the "My Way"

Frank

[Peter Germann]

Have you lost patience with the pusher props and gone back to tractors?  Your analysis of the pushers and inline design was excellent with the "My Way" design.  I still think the pushers have something positive to contribute.  The clockwise flyers were successful in the long run.

I am honored by a flyer of your status building and flying one of my designs. It is indeed the case that pusher drives, provided that the design of the model is adapted accordingly, offer some operational advantages. The only small problem is the very limited availability of propellers.

The reason for my switch to tractor propellers is that I wanted to use Igor Burger's adaptive power control on two new airplanes (Citation & Citation Two) which is why I bought all the components, including the ultra-light 12 x 5 3-blade tractor propeller, from Igor. Meanwhile both models are flying and I am impressed by the intelligent way of power control.

My compliments for the paint work on "Your Way" and kind regards

[Matt Piatkowski]

Hello Peter,
I suggest you try 11x6x4 tractor carbon composite wide PolProp from Tomek Jadczak.

I have used Igor's 12x5x3 narrow and wide propellers since 2017 and could not believe how efficient 11x6x4 was. One of my F2B planes (1812 RTF weight, Plettenberg 15-22, TP 6S 2800, Spin66F2B, Target Throttle=145, and Igor's active timer) used about 2100 mAh to fly the pattern in small to moderate wind at 5.28 seconds per horizontal lap with 5 minutes 20 seconds flight time.

After switching to 11x6x4 Polprop ( and adjusting the Target Throttle to 128), the battery uses only about 1640 mAh. for pattern flight to maintain the same lap time. There is also sufficient power overhead and stronger winds, with the timer's sensitivity = about 50.

All this means that I can switch to 6S 2200 battery and save about 40 grams, bringing the RTF weight to 1772 grams.

Tomek's propellers (PolProp) usually need some balancing, but this was relatively easy in the case of 11x6x4.

The weight of the 11x6x4 wide blade is 25 grams.

I also switched to a little spinner and saved about 8 grams here.

Best Regards,
M

[Peter Germann]

All this means that I can switch to 6S 2200 battery and save about 40 grams, bringing the RTF weight to 1772 grams.

Interesting, Matt, thank you.
As you can see in the attached setup list for my Citation the 1'700 mAh recharge of the 6S2700mAh Battery is quite similar to your 11 x 6 4 numbers and I assume that loading the 25C battery so low will make it last for many flights.
Yes, it might be possible to use a lighter 6S2200 battery but as the minus 40+Grams would definitely shift my CG out of the adjustable range, options would be either lenghtening the nose or adding nose weight. So, for the time being I plan to carry on as is flying both Citation and Citation Two with the 19 Gr. 12 x 5 N 3 driven by the AXI 2826/13 710 (which does not heat above 60°C when measured immediately after landing) from a low cost Zippy 6S2600 25C.

Kind regards

p.s. I use no spinner at all which may well be one of reasons the motor keeps from becoming hot. And it saves some 25 Grams, too...

[Igor Burger]

That is strange Peter, but I saw to fly your model last week. Are you sure you did not fly in Wloclawek? : - )))))))))))))))))
(just kidding)

An to the props - my combo 6 cells, motor with kv~700 is prepared for props with pitch up to 5". I think going to 5.5" or even 6" is not good idea, it means higher currents in motor. Those props need either lower KV (probably larger motor) or lower number of cells with larger capacity.

Speaking about number of blades - I see only one good reason to fly 3 blade prop, and it is its mass distribution. 1 or 2 blade props will shake in cornes and kill those tiny balls in bearing of electric motors. 3 blade prop has mass distribution in 2 axes, so it solves the problem. No reason for 4 blades. IMHO 4 blade prop must have lower efficiency at the same aerodynamic properties (thrust and speed stability). The more blades the worse result.   

[Peter Germann]

That is strange Peter, but I saw to fly your model last week. Are you sure you did not fly in Wloclawek?   

The swiss c/l committee has helped to provide Claude Russbach with "my model" and this proved to be a very successful investment. From his report when back from Poland today I dare to say that the man is now totally sold to our matter...