How do you measure incidence?
04-27-2002, 04:50 AM
#1
Thread Starter
My Feedback: (1)
Join Date: Dec 2001
Location: Cape Coral FL
Posts: 517
Likes: 0
Received 0 Likes
on
0 Posts
How do you measure incidence?
Ok - I have been in the hobby for a while and still don't know how to use my incidence meter. I can't take it anymore and need to get some answers!!
I assume you need to level the fuselage and use the meter on the wings and tail to get the correct incidence. The question is, how to hold the fuselage level and mount the wings at the correct incidence?
Could someone give me a detailed explanation?
I assume you need to level the fuselage and use the meter on the wings and tail to get the correct incidence. The question is, how to hold the fuselage level and mount the wings at the correct incidence?
Could someone give me a detailed explanation?
04-27-2002, 09:33 AM
#2
My Feedback: (62)
Join Date: Dec 2001
Location: Vineland,
NJ
Posts: 3,856
Likes: 0
Received 0 Likes
on
0 Posts
Details, Details
I'm not a rocket scientist, but here's how I see it. First, it somewhat depends on the design of the plane you are setting up as to what the numbers should be in the first place. I'll keep it simple with a 0 - 0 - 0 explanation. Understand though that there is a myriad of measurement differences in the plethora of planes out there 
Some trainers and sport designs may have some negative in the stab and positive in the wing for instance. Check out this thread when you're done here for some other interesting observations -->
http://www.rcuniverse.com/showthread...499&forumid=19
Anyway, to preface all of this, let's assume that most (most) designs will have a removeable wing and fixed stab. That being said, I normally set my foam Robart stand on my workbench with the plane and wing together sitting in the saddle. I use a level to shim the plane or stand so as to get a level or 0° reading on the stab. Use rubberbands and removable screw eyes or something in your table to keep the plane and stand still. Once secured and zeroed on the stab, move the meter to the wing. This is not always easy because of the ailerons.(The plot thickens)
You should be getting the hint that this procedure is best done in the building phase.
If the ailerons become a problem, use the root of the wing. This
may cause you to purchase from Robart their extended aluminum bar ($$) I guess you can make one too. Once you have a reading on the wing it is usually easy enough to shim the front or rear of the saddle with some wood or whatever it takes to dial in your readings. Robart also makes provisions to take engine thrust readings with their meters. Most times the kit designer will give you these numbers, some will not saying that everything is built in. Oh well!
This may sound complicated but it really insn't and makes all the difference in the world between a real nice flying, low maintenance fun model, and a DOG! Wish more people asked the question you're asking and would take the time to experience smooth flying. It also pays to take measurements with the meter to make sure the wing and stab are in the same plane of reference. That is to say that they are parallel to each other. If not, again shim the sides of the saddle with some tape or something. Haven't visited the Robart site lately, but maybe a more technical explanation awaits you there. Good luck and let me know if you have any other questions_Bobb
Some trainers and sport designs may have some negative in the stab and positive in the wing for instance. Check out this thread when you're done here for some other interesting observations -->http://www.rcuniverse.com/showthread...499&forumid=19
Anyway, to preface all of this, let's assume that most (most) designs will have a removeable wing and fixed stab. That being said, I normally set my foam Robart stand on my workbench with the plane and wing together sitting in the saddle. I use a level to shim the plane or stand so as to get a level or 0° reading on the stab. Use rubberbands and removable screw eyes or something in your table to keep the plane and stand still. Once secured and zeroed on the stab, move the meter to the wing. This is not always easy because of the ailerons.(The plot thickens)
You should be getting the hint that this procedure is best done in the building phase.
If the ailerons become a problem, use the root of the wing. This
may cause you to purchase from Robart their extended aluminum bar ($$) I guess you can make one too. Once you have a reading on the wing it is usually easy enough to shim the front or rear of the saddle with some wood or whatever it takes to dial in your readings. Robart also makes provisions to take engine thrust readings with their meters. Most times the kit designer will give you these numbers, some will not saying that everything is built in. Oh well!
This may sound complicated but it really insn't and makes all the difference in the world between a real nice flying, low maintenance fun model, and a DOG! Wish more people asked the question you're asking and would take the time to experience smooth flying. It also pays to take measurements with the meter to make sure the wing and stab are in the same plane of reference. That is to say that they are parallel to each other. If not, again shim the sides of the saddle with some tape or something. Haven't visited the Robart site lately, but maybe a more technical explanation awaits you there. Good luck and let me know if you have any other questions_Bobb
04-27-2002, 12:37 PM
#3
Thread Starter
My Feedback: (1)
Join Date: Dec 2001
Location: Cape Coral FL
Posts: 517
Likes: 0
Received 0 Likes
on
0 Posts
How do you measure incidence?
Bob,
Thanks for the reply, I understand now. One more question, what happens if the wing has washout? Do you measure and the root of the wing?
Thanks for the reply, I understand now. One more question, what happens if the wing has washout? Do you measure and the root of the wing?
04-28-2002, 10:30 AM
#6
My Feedback: (62)
Join Date: Dec 2001
Location: Vineland,
NJ
Posts: 3,856
Likes: 0
Received 0 Likes
on
0 Posts
Wow, You'll be busy
In that case, just try to stay within the specs of the plans. Take measurements from them when possible or try to contact the manufacturer. Remember to keep parallel as well as correct incidences_bob
04-28-2002, 11:46 AM
#7
How do you measure incidence?
Wombat;
Washout is measured at the tips usually. I don't remember the Byron's having washout, but! if the plans state washout then by all means set it in. Most likely it won't be over 2 Deg and 1 deg is common on some aircraft.
Byron kits have foam wings so the construction is straight forward. After trial fitting the wing take an incidence meter and start at the root and ease it out checking washout every 6" till you get to the tip. Your washout will be at it's maximim by the plans when you get to the tip. This way any modifications to the wing can be made prior to sheeting. Then after sheeted trial fit it again and insure the incidence has not changed. With the washout they have probably found that if at 0-0-0 they had a slight tip stall and are inducing a little washout to alleviate it, or make it less likely to tip stall.
Myself I use three (3) Incidence meters on most aircraft.
1. Firewall
2. Wing
3. Stab
All set at 0. Then I Move the 1 Incidence meter to check lateral alignment. This insures my aircraft are perfectly inline with the datum/ and they fly straight off the drawing boards.
Washout is measured at the tips usually. I don't remember the Byron's having washout, but! if the plans state washout then by all means set it in. Most likely it won't be over 2 Deg and 1 deg is common on some aircraft.
Byron kits have foam wings so the construction is straight forward. After trial fitting the wing take an incidence meter and start at the root and ease it out checking washout every 6" till you get to the tip. Your washout will be at it's maximim by the plans when you get to the tip. This way any modifications to the wing can be made prior to sheeting. Then after sheeted trial fit it again and insure the incidence has not changed. With the washout they have probably found that if at 0-0-0 they had a slight tip stall and are inducing a little washout to alleviate it, or make it less likely to tip stall.
Myself I use three (3) Incidence meters on most aircraft.
1. Firewall
2. Wing
3. Stab
All set at 0. Then I Move the 1 Incidence meter to check lateral alignment. This insures my aircraft are perfectly inline with the datum/ and they fly straight off the drawing boards.
