Go Back  RCU Forums > RC Airplanes > Questions and Answers
Reload this Page >

PLEASE HELP PLANE CLIMBS AT LOW SPEED AND DIVES AT FULL THROTTLE

Notices
Questions and Answers If you have general RC questions or answers discuss it here.

PLEASE HELP PLANE CLIMBS AT LOW SPEED AND DIVES AT FULL THROTTLE

Old 01-13-2007, 06:15 PM
  #1  
STEVESRCWORLD
Senior Member
Thread Starter
My Feedback: (23)
 
Join Date: Sep 2004
Location: PAGELAND, SC
Posts: 205
Likes: 0
Received 0 Likes on 0 Posts
Default PLEASE HELP PLANE CLIMBS AT LOW SPEED AND DIVES AT FULL THROTTLE

I HAVE JUST FINISHED A KMP 30% EDGE AND MAIDENED IT TODAY. IT DIVES AT FULL THROTTLE AND CLIMBS AT LOW THROTTLE SETTINGS. WHICH WAY DO I NEED TO GO WITH THE ENGINE? UP THRUST OR DOWN? I HAD TO ADD UP ELEVATOR FOR IT TO FLY. THANKS
Old 01-13-2007, 06:26 PM
  #2  
BarracudaHockey
My Feedback: (11)
 
BarracudaHockey's Avatar
 
Join Date: Jul 2003
Location: Jacksonville, FL
Posts: 24,342
Received 67 Likes on 56 Posts
Default RE: PLEASE HELP PLANE CLIMBS AT LOW SPEED AND DIVES AT FULL THROTTLE

You have too much down thrust.

And typing in all caps is considered shouting.
Old 01-13-2007, 06:26 PM
  #3  
d_bodary
Senior Member
My Feedback: (85)
 
Join Date: Apr 2004
Location: trenton, MI
Posts: 1,529
Likes: 0
Received 1 Like on 1 Post
Default RE: PLEASE HELP PLANE CLIMBS AT LOW SPEED AND DIVES AT FULL THROTTLE

You need to add some upthrust.
Old 01-13-2007, 06:31 PM
  #4  
STEVESRCWORLD
Senior Member
Thread Starter
My Feedback: (23)
 
Join Date: Sep 2004
Location: PAGELAND, SC
Posts: 205
Likes: 0
Received 0 Likes on 0 Posts
Default RE: PLEASE HELP PLANE CLIMBS AT LOW SPEED AND DIVES AT FULL THROTTLE

sorry for the all caps, just frustrated. i forgot to mention that when rolled inverted it actually climbs upward like your trying to pull a loop. i have never seen a plane behave this way. how much up do you think it needs?
Old 01-13-2007, 06:37 PM
  #5  
Nam Vet
My Feedback: (15)
 
Join Date: Sep 2005
Location: Weatherford, OK
Posts: 21
Likes: 0
Received 0 Likes on 0 Posts
Default RE: PLEASE HELP PLANE CLIMBS AT LOW SPEED AND DIVES AT FULL THROTTLE

I would start by adding 1-2 degrees of upthrust to your engine. Also, I would check the incidence of your wing and stabilizer.
Yours,
Bob
Old 01-13-2007, 07:08 PM
  #6  
STEVESRCWORLD
Senior Member
Thread Starter
My Feedback: (23)
 
Join Date: Sep 2004
Location: PAGELAND, SC
Posts: 205
Likes: 0
Received 0 Likes on 0 Posts
Default RE: PLEASE HELP PLANE CLIMBS AT LOW SPEED AND DIVES AT FULL THROTTLE

to be honest i don't know how to check it. i do have a meter though just never really any instruction on how to use it.
Old 01-13-2007, 09:35 PM
  #7  
Nam Vet
My Feedback: (15)
 
Join Date: Sep 2005
Location: Weatherford, OK
Posts: 21
Likes: 0
Received 0 Likes on 0 Posts
Default RE: PLEASE HELP PLANE CLIMBS AT LOW SPEED AND DIVES AT FULL THROTTLE

Read the instructions on how to check the wing incidence. You need to secure the wing to the fuselage to check it. From the leading edge of the wing to the trailing edge, the wing should be level in the wing saddle (0 degrees) of the fuselage. It sounds as if you need more upthrust in your engine. Usually you can add upthrust by adding flat washers under the front of your engine where it attatches to the engine mount.
Yours,
Bob
Old 01-14-2007, 08:55 AM
  #8  
BarracudaHockey
My Feedback: (11)
 
BarracudaHockey's Avatar
 
Join Date: Jul 2003
Location: Jacksonville, FL
Posts: 24,342
Received 67 Likes on 56 Posts
Default RE: PLEASE HELP PLANE CLIMBS AT LOW SPEED AND DIVES AT FULL THROTTLE

Ahh good call! I didnt think about that, he mentioned thrust angles and incidence didn't occur to me.
Old 01-14-2007, 09:34 AM
  #9  
da Rock
Senior Member
 
Join Date: Oct 2005
Location: Near Pfafftown NC
Posts: 11,511
Likes: 0
Received 0 Likes on 0 Posts
Default RE: PLEASE HELP PLANE CLIMBS AT LOW SPEED AND DIVES AT FULL THROTTLE

Changing the engine thrust OR changing the wing's incidence both work. And some people consider that it's a tossup which one to do. But if you think about it, it's not always a tossup.

If the wing and stab are correctly aligned then changing the wing incidence is dirtying up the airplane. So you don't want to automatically shim the wing and forget it.

It's always seemed that the best first test is to the engine thrust. When you've got that sorted, then look at what elevator trim the airplane winds up with. If the airplane has then taken some elevator trim after the thrust line is sorted, consider changing the incidence to do some of the thrust adjustment.

Truth is, whether or not the thrust needed sorting, it's never a bad idea to consider dinking with the incidence to straighten out your elevator trim. But when you have discovered the need for a thrust change and the motor mount has a stack of washers under it, you've got the perfect time and reason to get rid of some of those washers if you can. And if you can, then it often winds up straightening out the elevator trim. Less washers, less elevator trim. Straighter airplanes fly better, faster, and with less drag.
Old 01-14-2007, 10:19 AM
  #10  
DadsToysBG
My Feedback: (35)
 
Join Date: Jul 2003
Location: Bowling Green, KY
Posts: 2,497
Likes: 0
Received 0 Likes on 0 Posts
Default RE: PLEASE HELP PLANE CLIMBS AT LOW SPEED AND DIVES AT FULL THROTTLE

There's one other thing that could cause this. If the plane is tail heavy every time you pull the throttle back it want's to swap ends. As you add throttle the elavator gets real touchy and that could account for the trim change. Dennis

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


Thread Tools
Search this Thread

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

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.