Question on Engine Thrust - Page 2 - RCCanada - Canada Radio Controlled Hobby Forum
RCCanada - Canada's Radio Control Hobby Forum
General RC Aircraft Discussion Discuss anything RC related

Closed Thread
Thread Tools Display Modes
Old 09-17-2004, 09:43 AM   #11
RCC Supreme Contributor
ronm's Avatar
I am: Ronm
Join Date: Dec 2002
Location: Mission, B.C.
Radio of choice:
# of RCs: 10

Feedback: 0 / 0%
Posts: 5,625
Total Props: 0

       Remove this ad - become a site supporter!
I like the article that gives the full scale examples, it makes it easier to visualize what is actually happening.
Ron Mattiuz

Flying Tigers RC Club
"Flying an airplane is just like riding a bike...except it's harder to put cards in the spokes"
ronm is offline   Quick reply to this message.

Sponsored Links - Subscribe to remove this ad.
Old 09-17-2004, 10:51 AM   #12
I am: Boolean21
Join Date: Sep 2002
Location: Singapore

Feedback: 0 / 0%
Posts: 38,228
Total Props: 56
Originally Posted by JimMcIntyre
Originally Posted by Ed Smith
Not to question all that has been written on this subject but, These forces seem to have their effects only at takeoff....
Good articles.

Try watching any flyer who competes. You'll notice they input rudder for every change in pitch (adding right rudder when performing and inside loop for example). Sure, you can perform most maneuvers (such as a loop) without correcting for P factor (or wind) but, it the aircraft won't exit the maneuvre on the same heading....
Actually the more current trend is to use bank angle to compensate for heading deviations, as rudder corrections are often times easy to see. If done properly you cant see a model bank 2 degrees

Right thrust is a strange animal, and there are lots of theories and what not about the correct use of it. Some guys like Chip Hyde use very little and deal with heading changes by using a throttle to rudder mix. Others use a lot of right thrust and just deal with the problems it brings.

The idea behind it is so that at low speeds and high throttle settings (takeoff, long vertical climbs etc.) the engine will prevent the plane from moving to the left. You cannot completely eliminate this and have a good flying model, its just not a realistic thing to acheive. You basically want to have enough right thrust that the model will track vertically, not forever but for as long as is required for your type of flying.

Too much right thrust will cause problems in loops, hard corners etc, it just wont fly as it should. Too little right thrust will give you headaches when trying to fly a straight vertical line. It can also effect horizontal flight. Right thrust also aggrevates the P-factor effect during inverted flight, so too much is a really bad thing if you spend lots of time upside down.

Right thrust is also very specific to the throttle setting, so it really depends on prop, engine output, aircraft speed. Since it is power dependant temperature and humidity changes effecting engine performance will change how much of an effect it has.

I have seen pattern models of the same design have thrust variations of over 2 degrees (which is a lot) depending on each flyers particular setup and their own personal feel for the model. Most designers have thrust built in for a specific configuration, change that and the thrust will need to change.

Its a real trial and error type setting, keep trying different thrust positions make a number of flights on the model to get a feel for it. Change the thrust and note if it is an improvment or not. Always record your observations/configurations somewhere, in the future you can use past experience to make more educated choices for thrust positions.

This is a really gray subject, bottom line is right thrust will fix one part of all these phenomenon and the rest you just have to learn to fix with your fingers.
PurgatorY is offline   Quick reply to this message.
Old 09-17-2004, 11:36 AM   #13
RCC Supreme Contributor
JimMcIntyre's Avatar
I am: Jim McIntyre
Join Date: Aug 2002
Location: Claremont Ontario
Radio of choice:
# of RCs: 999

Feedback: 1 / 100%
Posts: 4,345
Total Props: 1
Also, many designs, including full scale, will offset the fin to correct for P factor....
MAAC# 12719
Si fractum non sit, noli id reficere - (If it ain't broke, don't fix it).
JimMcIntyre is offline   Quick reply to this message.
Old 09-17-2004, 12:44 PM   #14
I am: Boolean21
Join Date: Sep 2002
Location: Singapore

Feedback: 0 / 0%
Posts: 38,228
Total Props: 56
Originally Posted by JimMcIntyre
Also, many designs, including full scale, will offset the fin to correct for P factor....
This is the same effect as using rudder trim, problem is it is speed dependant and one setting wont work for the entire flight. Also you need left rudder for inverted stuff. So unless you have a variable angle fin that can be mixed to throttle right thrust is still a better solution.

Plus a fin angle will have serious effects during knife edge flight, and will also effect pitching (which is fairly common during knife edge) due to the change in rudder use of one side vs another, the explanation of that is an entire new topic though.

One could write a dissertation on how to correctly trim a model for precision flying It takes me in the area of 200 flights to get a new plane setup correctly to minimize the amount I have to fly it My thought process is, the more the airplane does by itself, the less chance I have to FUBAR the manouver LOL

This is going to sound wierd, but one way I found to get really straight uplines without adding right thrust was to add 1/8" wide sticks to my rudder TE as shown in the picture. Dont ask me to explain it because I cant, but it worked for me......

PurgatorY is offline   Quick reply to this message.
Old 09-17-2004, 09:27 PM   #15
RCC Junior Contributor
I am: Colin J
Join Date: Apr 2004
Location: Regina, Sask
Radio of choice:
# of RCs: 4

Feedback: 0 / 0%
Posts: 146
Total Props: 0
thanks everyone!

thanks everyone!
Colin Jensen
Regina Windy Flyers
cjensen is offline   Quick reply to this message.
Closed Thread

Quick Reply

Register Now

In order to be able to post messages on the RCCanada - Canada Radio Controlled Hobby Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

Member names may only be composed of alpha-numeric characters. (A-Z and 0-9)

!!ATTENTION ADVERTISERS!! If you intend on advertising anything on this forum, whatsoever, you are required to first contact us here . Additionally, we do NOT allow BUSINESS NAMES unless you are an Authorized Vendor. If you own a business, and want to do sales on this site via posting or private message, you will need to follow the rules. Shops, Stores, Distributors, Group Buys without being authorized will see your account terminated.
User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Your Name
Your first name and last initial is required if you plan on using the forum.
Which city & province you live in. This is mandatory for classified listings.
Radio of choice?
Which radio is your current favorite to use?
Number of RC Vehicles?
How many boats, cars, planes do you own?


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
vBulletin Message

Thread Tools
Display Modes

Forum Jump

All times are GMT -5. The time now is 08:50 PM.

vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2016 DragonByte Technologies Ltd.