Logo
Builders' Plan Gallery  |  Hip Pocket Web Site  |  Contact Forum Admin  |  Contact Global Moderator
April 08, 2020, 04:34:36 AM *
Welcome, Guest. Please login or register.
Did you miss your activation email?

Login with email, password and session length
 
Home Help Search Login Register
Pages: [1]   Go Down
Print
Author Topic: Trimming A Pusher Model  (Read 142 times)
0 Members and 1 Guest are viewing this topic.
ssmith
Bronze Member
***

Kudos: 0
Offline Offline

United States United States

Posts: 15


Topic starter


Ignore
« on: March 23, 2020, 07:20:24 PM »

As part of my "Social Distancing" I decided to build something I could fly in my living room - a "Parlor Pusher" (the plans are in the Plans Gallery).
I decided to build it pretty much to plan - 9 1/2" wingspan, no camber in the wing ribs or prop blades. It is covered with condenser paper and came out to 2 grams finished.  I could definitely build it lighter but wanted to see how it would fly as originally conceived.

This is my first pusher model and I have no experience with trimming a pusher model.  When looking from the rear the prop rotates counter-clockwise.   The model flies in a tight right-hand circle approx 6 ft in diameter at about head height.  I have been trying to open up the turning circle and added some some aleron tabs to the wing to introduce some left roll but without much effect.

The plan doesn't have any trimming instructions - how should the flying surfaces be adjusted for a better pattern?
Attached files Thumbnail(s):
Trimming A Pusher Model
« Last Edit: March 23, 2020, 07:31:53 PM by ssmith » Logged
ironmike
Platinum Member
******

Kudos: 89
Offline Offline

United States United States

Posts: 1,170



Ignore
« Reply #1 on: March 23, 2020, 08:05:43 PM »

I would play with wing tip weight to get turn.
Logged
dputt7
Titanium Member
*******

Kudos: 92
Offline Offline

Australia Australia

Posts: 2,035




Ignore
« Reply #2 on: March 23, 2020, 08:30:15 PM »

    I fly my Indoor models to the Left. You can see the thrust offset required on my Zephyr, also as Mike says some tip weight on the foreplane.
Attached files Thumbnail(s):
Re: Trimming A Pusher Model
Re: Trimming A Pusher Model
Logged
flydean1
Platinum Member
******

Kudos: 23
Offline Offline

United States United States

Posts: 1,037



Ignore
« Reply #3 on: March 23, 2020, 10:55:54 PM »

A canard can sometimes be persuaded to turn by tilting the canard in the desired direction.
Logged
ssmith
Bronze Member
***

Kudos: 0
Offline Offline

United States United States

Posts: 15


Topic starter


Ignore
« Reply #4 on: March 24, 2020, 01:56:14 PM »

dputt7, Ironmike -

Thanks for the suggestions.  

I now have the model flying in a left-hand circle.  I had used a pigtail prop bearing and it appears that it may have been too flexible to maintain the desired thrust offset once the wound rubber was attached.  I stiffened up the bearing and added a bit more left-hand offset as well as adding a bit of weight to the in-board canard as suggested.

It now flies in a larger circle and I am now trying to dial-in the the rubber size and launch torque.  It is certainly sensitive to the launch attitude and not surprisingly does not recover very well if it encounters and obstacle.  

I think I will also build a new prop with an adjustable hub so that I can tweak the prop pitch a bit.

Thanks for your help.

Steve

« Last Edit: March 24, 2020, 02:08:14 PM by ssmith » Logged
Pages: [1]   Go Up
Print
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.21 | SMF © 2015, Simple Machines Valid XHTML 1.0! Valid CSS!