Scratch and Kit Built Aircraft Discuss and share your scratch built or kit built aircraft as well as building techniques, methods, mediums and resources.

A Different Type of Rudder

Old 03-23-2015, 06:59 PM
  #1  
pcm10xmode
Member
Thread Starter
 
Join Date: Jan 2015
Posts: 59
Default A Different Type of Rudder

I built the Stuntcat awhile back because it was a "different" plane and seemed to handle well with good stability in an elevon setup having endplates as rudders. As the winds build, best said, I couldn't put it where I wanted.

Decided to explore putting a movable rudder in front of the prop. As you can see, dropped a hitec 55 servo in the channel hump, grabbed a large servo arm (3") and hotglued a rudder to it and then installed it.

Does it (blockage) reduce the prop's efficiency and does it give 3 axis of control?
Don't notice the difference in power(it ain't a speedster) and gives me full control in the winds. A side note, it improved the "highalpha" control and you can really stear it around. Reason I didn't do sideplates was I would end up tearing it all apart.
Attached Thumbnails Click image for larger version

Name:	stuntcat rudder 001.JPG
Views:	182
Size:	493.2 KB
ID:	179927  
pcm10xmode is offline  
Old 03-23-2015, 09:02 PM
  #2  
quorneng
Super Contributor
 
quorneng's Avatar
 
Join Date: Jul 2008
Location: Cheshire, UK
Posts: 2,036
Default

Yes it will reduce the prop's efficiency a bit - it would be rather better if the fin was a true streamline profile - I would expect you can probably hear a different prop note when its at full deflection.

I would be more concerned that you are relying entirely on a hot glue joint to hold the fin in place.
Second you are loading the servo bearing in a way it was never intended to take.
Third if anything does fail the fin goes straight into the prop.

Nevertheless a neat solution to give a degree of rudder control.
quorneng is offline  
Old 03-23-2015, 10:05 PM
  #3  
mclarkson
Super Contributor
 
mclarkson's Avatar
 
Join Date: May 2010
Location: Wichita, KS
Posts: 3,958
Default

Yeah - I hate hot glue. Cool idea though. Let us know how it holds up.
mclarkson is offline  
Old 03-23-2015, 11:54 PM
  #4  
theapplepi3.14
Totally Non-Newtonian
 
theapplepi3.14's Avatar
 
Join Date: Mar 2015
Location: My House
Posts: 280
Default

I think the X-15 used this technique too! Cool eh?
theapplepi3.14 is offline  
Old 03-24-2015, 04:20 PM
  #5  
pcm10xmode
Member
Thread Starter
 
Join Date: Jan 2015
Posts: 59
Default

Originally Posted by quorneng View Post
Yes it will reduce the prop's efficiency a bit - it would be rather better if the fin was a true streamline profile - I would expect you can probably hear a different prop note when its at full deflection.

I would be more concerned that you are relying entirely on a hot glue joint to hold the fin in place.
Second you are loading the servo bearing in a way it was never intended to take.
Third if anything does fail the fin goes straight into the prop.

Nevertheless a neat solution to give a degree of rudder control.
Agree, if failure, would probably go into prop.
I fly it quite often(precheck it) and have no issues with the hot glue holding it. When I do flybys, no fluttering is taking place when rudder is deflected. With the servo centered on the rudder, deflection forces counteract and reduce the servo's bearing load. I have used this design on other planes and it works.
Grant it, if you reef it around, it would probably destroy itself.
I designed it so that you have 3 axis control in any condition. From here, I know pilots will modify it or try something else.
pcm10xmode is offline  
Old 03-24-2015, 06:09 PM
  #6  
Wildflyer
Past President of PSSF
 
Wildflyer's Avatar
 
Join Date: Sep 2009
Location: Lacey WA, 1 mile E of Mushroom Corner
Posts: 2,195
Default

You could make a more durable system, by drilling down through the fuselage and gluing a tube in the hole, then building the rudder with a extended post at the normal spar line. make some kind of cap to hold the rudder in place. Now mount the servo any where you want.

This way the servo is not holding the entire load, it is just working as designed. Also you wouldn't have the risk of glue failure sending the rudder into the prop.

If the tube and post were made from carbon fiber, they would be very light and strong.

The whole thing is just a variation on the 2 piece removable wing system that most aerobatic planes use.

You have a cool idea, I would enjoy watching it fly.
Wildflyer is offline  
Old 03-24-2015, 07:04 PM
  #7  
fhhuber
Super Contributor
 
fhhuber's Avatar
 
Join Date: Mar 2013
Posts: 4,786
Default

"flying" stabilizers have been used for a long time. The Wright Flyer rudders didn't have a fixed fin.
fhhuber is offline  
Old 03-24-2015, 09:37 PM
  #8  
Bill G
Super Contrubutor
 
Bill G's Avatar
 
Join Date: Oct 2005
Location: West Central PA
Posts: 4,422
Default

Originally Posted by pcm10xmode View Post
Agree, if failure, would probably go into prop.
As long as the motor's mounted well, that APC prop should take care of the shredding job without issue.
Bill G is offline  
Old 03-25-2015, 02:47 PM
  #9  
pcm10xmode
Member
Thread Starter
 
Join Date: Jan 2015
Posts: 59
Default

Prop is about 2" from rudder. Will do a video after snow is gone. I use a 7" wide prop so Rpm's are down. It is so sensitive that I doubt that the max angle of deflection(guessing from rudder movement) is about 20-25 degrees.
Hey, it works, why invent the wheel again.
pcm10xmode is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
AEAJR
Beginners
166
11-02-2021 02:03 PM
AEAJR
General Electric Discussions
225
05-27-2020 06:48 PM

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Quick Reply: A Different Type of Rudder


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.

Page generated in 0.09173 seconds with 17 queries