Cub Jigs
- Thread starter nesincg
- Start date
mike mcs repair
Registered User
chugiak AK
jigs, are nice, and a fast way to do things, pretty closely.....
but if you have good and properly trammed wings installed, you can just measure back to tail spring attach bolt and do BETTER than most jigs around..(much better than Piper did...)...
but if you have good and properly trammed wings installed, you can just measure back to tail spring attach bolt and do BETTER than most jigs around..(much better than Piper did...)...
Steve Pierce
BENEFACTOR
Graham, TX
Talk to Tim about the guy in TN. :roll: I prefer repairing in my jig and all the sub jigs we have built over the years. Makes things easier, quicker and more repeatable results. Sorry I don't know of any in your area. To quote Tim "get your credit card out and call Univair". 8) 
old guy 46
FRIEND
I have one that is in maine if anyone needs one in the north east.
nesincg
BENEFACTOR
Chattanooga, TN (KAPT)
Woohoo. Thanks for the post. I miss Maine, some days. That's two in the whole country.
Mike there is not much you ever say that I don’t completely agree with on here but measuring back from wings tells you nothing about AOI built into the fuselage which is everything that makes a cub fly like a cub. Even more important than having the correct AOI is having the SAME AOI on both sides. Cubs with much difference have Nasty Stall/Spin characteristics and will try hard to kill you..I learned to fly In one and it was always ready to bite hard. S2D and I did a bunch of turns and several thousand feet trying to recover, fixed the AOI and it became a real performer that the Grand Father of SC.org has proudly called his own for many years.
dave
mike mcs repair
Registered User
chugiak AK
not true at all...
even the jig that i used that was made from a never flown surplus piper fuselage was 1/2 degree different at root, 1" different from rear wing attach to tailwheel bolt(Airframes has this jig now, the yellow one out of Homer)
and over 1 degree at wing root is VERY common on flying cubs...(you just split the difference when determining level flight)
and add to that the difference between a real piper rear spar attach height & a unavair one seems to be just over 1/8" different height....
from rear wing strut attach to tail bolt 1" difference is normal(jig mentioned above made from unflown piper fuselage)
but on this field I know of one that's 5" different .... they won't go slow well like that... but ... It's been a working hunting cub for decades....
supercrow
FRIEND
Smith Pond near Millinocket, Me
A month or so ago we rigged one here for an owner who said that it had a very heavy wing. It turned out to be about 1deg. different on the two sides of the fuselage. It is an older exp. and I don't know much of the 40 yr. old history. After making some strut adjustments, the owner says it flies very well and he is happy with it. Doing measurements on this one would drive you crazy but the end result is that is flies like every other cub that is set up to fly well. I haven't flown it myself and can't speak to the stall characteristics. I don't think this fuselage is any different than a lot of factory or hand built fuselages. They seem to vary greatly. Mine was hand built in a very good jig and it showed when we rigged it and flew it. A higher time pilot than myself flew it 25 hrs. last winter and said it was the straightest flying one he has flown. It is a pleasure to fly a straight and well balanced heavier s. cub that feels more like a J-3 or PA-11.
Steve Pierce
BENEFACTOR
Graham, TX
I have measured more Super Cubs than I care to think about. I have rebuilt 5 that had never been apart. I also have a mid 1970s surplus fuselage that still has the build number and part number written in red crayon on the front tubes. Piper built them all over the place. I have seen some with lots of incidence, not much incidence and lots of variation between the left and the right. My jig got built off a frame that Wayne Mackey did and it measured out very well and everything that has come out of it has flown very well. I figured out to measure everything, install the tail, measure the stab up and down and the elevator throws before blast and prime. Several that were never wrecked or repaired didn't meet the TCDS. I want all it says and if it says +/-5 I want all of that 5. My personal feeling is that a fuselage is only as good as the jig it came out of or the attention to detail the person put into getting all the angles correct. We have figured out what flies nice and that has been a game changer.
old guy 46
FRIEND
My jig was built off a new Univar fuselage.
Steve Pierce
BENEFACTOR
Graham, TX
Steve Pierce
BENEFACTOR
Graham, TX
I installed a new Univair frame in my jig several years ago and it fit good, the rear wing attach fittings were a little higher than mine.
Where are you located? Are you repairing fuselages?
supercrow
FRIEND
Smith Pond near Millinocket, Me
And it works very well, thank you.
RaisedByWolves
FRIEND
Tx
RaisedByWolves
FRIEND
Tx
Steve didn’t you have a Univair that didn’t fit well in the jig?
Sent from my iPhone using Tapatalk
Sent from my iPhone using Tapatalk
Steve Pierce
BENEFACTOR
Graham, TX
The fuselage was a little high
supercrow
FRIEND
Smith Pond near Millinocket, Me
Steve, that is the jig that my fuselage was built in and it came out very well. He has repaired and rebuilt quite a number of fuselages over the years. Can do J-3, 18 or 12. Milo, Maine.
cubdriver2
FRIEND
upstate NY
Mike Pynne? New life restoration in Tenn. Paul Babcock uses him for fuselage repair
Glenn
So you have a fuselage that measures 1 degree on the left and the max allowable 2 degrees on the right...this is from the horizontal reference to the bottom of the wing which is about the only easy way to measure a flying airplane without taking it apart.if you rig both wings by the book it will fly left wing heavy all else being equal. So now you have a choice on how to make it fly hands off, take some twist “washout” out of the left wing to give it more lift or put more washout in the right to give it less lift.
The problem is that the wings rigged to fly hands off on a bad fuselage stall differently,the one with less AOI and less washout will stall more completely end to end and the right side which is making more lift at the butt and a lot less at the tip will usually but not always stall first. This scenario makes normal spin recovery null and void and you now a unpaid test pilot. I learned to fly in such a beast and was scared witless more than once at low altitude by its extremely poor manners
steve p is exactly right even factory built never damaged airplanes are off and can be made to fly/perform better with a good jig and someone that knows what to look for.
dave
The problem is that the wings rigged to fly hands off on a bad fuselage stall differently,the one with less AOI and less washout will stall more completely end to end and the right side which is making more lift at the butt and a lot less at the tip will usually but not always stall first. This scenario makes normal spin recovery null and void and you now a unpaid test pilot. I learned to fly in such a beast and was scared witless more than once at low altitude by its extremely poor manners
steve p is exactly right even factory built never damaged airplanes are off and can be made to fly/perform better with a good jig and someone that knows what to look for.
dave
sportingrifle
Registered User
I have a forward fuselage jig that also jigs a zero degree engine mount. Built from drawings, very accurate. Located in British Columbia, Canada. About 3’ X 6’ X 8’, 100 lbs. Free to good home!
Kevin.
(250)466-0927
Kevin.
(250)466-0927
Gordon Misch
MEMBER
Toledo, Wa (KTDO)
Maybe. Depends on the cold stress. If in tension or neutral, yes, it will pull. If in compression, maybe just relax the joint.
Southern Aero
SPONSOR
kcco/1ga2
But there are ways to mitigate that.............................................
sportingrifle
Registered User
Jack leg….do you still want the fuselage jig? Give me a ring(250)466-0927
cheers Kevin
cheers Kevin
