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Dec 10, 2012, 05:22 AM
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Lantsov Alexey's Avatar
Quote:
Originally Posted by JanneL View Post
The power system is of course "the good old" coaxial system by Mr. Kimmo Kaukoranta
Kimmo and Janne.
What settings in the coaxial system?
You make the mix to the ailerons?
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Dec 10, 2012, 09:53 AM
Janne Lappi, F3A Team Finland
JanneL's Avatar
Hi Alexey,

yes we use aileron -> throttle mix. In torqueroll flight mode I adjust the mix so that I hover the plane with constant throttle and then start torqueroll. The height must stay the same despite the aileron input.

In normal flight mode there is a bit more mix than in torqueroll mode. I don't know how Kimmo uses this, but at least I have set the mix off at the bottom position of the throttle stick. I don't want that plane will accelerate during rolls in vertical downlines.

This helps a lot of course in torqueroll but also in rolls. Especially the rolls in vertical upline are much better because the climbing speed remains unchanged even though there are rolls.

Regards,
Janne L
Dec 12, 2012, 02:40 AM
Registered User
Kimmo Kaukoranta's Avatar
I have the same mixes as Janne, both throttles increase when applying aileron, except when the throttle lever is in the low position.

In the past I also experimented with differential throttle, so applying left aileron would increase only the front prop RPM and cause a left torque, but it caused some yaw in the rolls, not good.
Dec 12, 2012, 02:56 AM
Registered User
Kimmo Kaukoranta's Avatar
Christian, very interesting designs. I was pretty sure the co-runner idea had to be thought of by someone before us. Maybe we were just the only ones crazy enough to actually build it ;-)

The flex cable drive looks interesting, never thought of that. I guess the same could be done with two sets of bevel gears (90-degree angle drives) and straight shafts, maybe for better efficiency? It would still have just one motor. Or maybe even the quad prop design with either one or two motors in the center.

I built a similar ringless planetary gearbox earlier also from my sons's legos. The benefit is that you only need spur gears, small module ring gears do not seem to be easy to come by. The downside is that the diameter of the whole system will be larger for the same gear ratio compared to a "normal" planetary with the ring gear.
Dec 12, 2012, 06:12 AM
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Jurgen Heilig's Avatar
Quote:
Originally Posted by Kimmo Kaukoranta View Post
...
In the past I also experimented with differential throttle, so applying left aileron would increase only the front prop RPM and cause a left torque, but it caused some yaw in the rolls, not good.
Hi Kimmo,

you could use a switch to activate differential throttle mix just for the torque rolls.

Jürgen
Dec 12, 2012, 10:15 AM
Janne Lappi, F3A Team Finland
JanneL's Avatar
Quote:
Originally Posted by Jurgen Heilig View Post
Hi Kimmo,

you could use a switch to activate differential throttle mix just for the torque rolls.

Jürgen
Hi,

Kimmo means that the problem was exactly in torqueroll and in rolls during vertical uplines. The thrust angle has been adjusted straight with coaxial system. When a differential mix is used, another of the two props accelerates more. As a result of this, the straight thrust angle is now wrong, because the torque is not anymore neutralised. In horizontal rolls it's no problem but in vertical upline or torqueroll it causes some unwanted unstability.

Janne
Jan 29, 2013, 01:10 PM
Registered User
Lantsov Alexey's Avatar
Hi .
Now I made a new version of the coaxial system downgrade.
Reduction is 1:5
Weight of 12.9 grams.
Last edited by Lantsov Alexey; Feb 19, 2013 at 11:38 AM.
Jan 31, 2013, 11:17 AM
Registered User
Stular's Avatar
Now THAT is thinking out of the box
Motor sideways…of course…why not...
Feb 19, 2013, 11:34 AM
Registered User
Lantsov Alexey's Avatar
Hi Guys.
The coaxial system works !
Weight system with 7 grams of motor = 10.5 grams.
I made 2 props 10x3 and 10x3.5
The total weight of 15.2. gram.
Video system:
Lantsov coaxial system (1 min 42 sec)
Feb 21, 2013, 03:31 PM
Registered User

hi lantsov/ kimo


I am not a indoor flyer by my self,only outdoor,but I am very interested in building your differential systems and also Kimo's contra-runners.(brushed and geared).
I build your first differential (wrong motor,thus to heavy) and Kimo's brushed one as a unit .Thank's both of you.
Now I like to build Kimo's geared one ,but first Lantsov's latested differential,the reduction is simple to change and it is light. Lantsov can you tel me witch motor you have used and witch Kv the motor has. Thank you!
Feb 22, 2013, 03:35 AM
Registered User
Lantsov Alexey's Avatar
Hi Frans.
I used a homemade engine 22-3/45.
1400 rpm/volt
Feb 24, 2013, 12:04 PM
Registered User
hi lantsov
your motor is 1400 kv,the reduction is 5:1,so your prop has only 280 kv.
is that right?
Feb 24, 2013, 03:40 PM
Registered User
Lantsov Alexey's Avatar
Hi
1400 kv my first system without gears.
Now I use the motor 2000 kv /
Today I did a test flight with the new coaxial,
Very good result.
Flight now lasts 5 minutes.
And my plane is lighter by 5 grams.
Video test flight.
Соосная мотоустановка А. Ланцова 24.02.2013 (1 min 57 sec)
Mar 12, 2013, 01:02 AM
WingsTiresTitsGunaGiveYaT ruble
bill clark's Avatar
I have read through this entire thread and would like to say bravo to all of your successes. You guys are all great thinkers.
Lantsov, I think your latest design is great. Rediculously simple with ease of flexability in motor choice and front-rear differential ratios if desired. I would like to use your design on my next plane if you dont mind . Have you noticed any result of moving the motors torque and inertia from the roll to the yaw axis? Theoretically this seems like a good thing
Mar 12, 2013, 03:43 AM
Registered User
Lantsov Alexey's Avatar
In my coaxial system I use motors 7 grams weight.
Rotor weight only 2 grams.
The moment is very small and does not affect the flight.
I made more than 100 flights and see only positive result.
My new plane has a flight 7 minutes with 7.4 v. ACC. 120 mA.


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