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help with wing jigs
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I am building a pt-20 from great planes and it comes with a wing jig set to set the washout but how does it sit on this???? It look like in the picture it sits inside of the opening but the cord on the wing is to wide and it will not sit inside of it. Any help would be great. Here is a copy of the manual the will not let me copy a pic out of it. Page 32 shows what I am talking about.
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RE: help with wing jigs
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twostroke,
I have not built a PT-20; however, the attached schematics show what I understand from reading the manual: The central rib rests flat over the table, as well as both templates. The wingtips rest over the top of the templates, which are placed vertically (following the angle of the top). The trailing edge of the wingtips should be higher than the leading edges, while both edges are equally high for the central rib. If less dihedral is desired (sport version), the template is cut and overlapped, in order to make them shorter, while the washout remains the same. Best luck with the building of the kit! |
RE: help with wing jigs
That I understand, it is that the wing does not fit inside of the tabs on the jig the wing is to wide. if the wind was not as wide it would fit in there fine but right now if i put the leading edge in it the trailing end has to sit up on top of the tab.
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RE: help with wing jigs
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I see.
As the reason of the jig is to keep the same height and twist angle of the wing tips, you can just eliminate the tab of the leading edge. That modification will not affect either the height or the twist angle. Did you verify that the actual chord of your wing is as specified in the plan? According to Tower specs, it should be close to 9-3/4". |
RE: help with wing jigs
I did not verify but I built it over the plans so I assumed it was correct. Great idea of cutting them off, Why didn't I think of that[:@]
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RE: help with wing jigs
My first kit was a PT-60. It had the same type of washout jigs. I was confused about them so I talked to my instructor about washout and how to finish building my wing. He gave me a basic explanation of washout and then told me to just build the wing straight (zero washout). He said the big flat bottom wing really didn't need the washout and that he thought it would be easier to get the two wings more alike if I kept them as flat as possible on the building surface.
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RE: help with wing jigs
Ditto on eliminating the washout. I also built my PT60 with 0 washout and it flies great.
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RE: help with wing jigs
When I built my PT-40 I used the jigs and built the washout into the wing. Regardless of how effective it is, it does look cool with the washout in there and is not that hard to do. I tack glued the jigs to the wing tips and held the jigs down to the table with sandbags just like it shows in the manual. Once you have your sheeting in place you just carefully break the jigs off of the wingtips. It works good.
Did you build the A wing or the B wing? |
RE: help with wing jigs
twostroke, You did not say how much the chord is too long to fit in. It is odd that the manufacturer would supply a jig that is too short. I would build the washout. The model without washout flys nicely until it approaches the stalling speed. That is when you will appreciate the washout. Many fliers never come close to the stalling speed Like some fellows fly at full throttle all the time. Half a penny's worth. Zor |
RE: help with wing jigs
ORIGINAL: Zor twostroke, You did not say how much the chord is too long to fit in. It is odd that the manufacturer would supply a jig that is too short. I would build the washout. The model without washout flys nicely until it approaches the stalling speed. That is when you will appreciate the washout. Many fliers never come close to the stalling speed Like some fellows fly at full throttle all the time. Half a penny's worth. Zor |
RE: help with wing jigs
Its about a quarter inch to long and thats why I ask about it here I though something cant be right here with the kit being from great plane usally there kits are pretty good and instruction are very good!!! Make it 8.75 ; the difference is only 53 thou ( 53 / 1000 of an inch ). Your chord is about 1/4" too long. That is 250 / 1000 of an inch. What is your actual chord on the drawings? What is your chord measured on the wing assembly ? What is the distance measured on the jigs ? I know you assembled the wing over the drawing but please make actual measurements. I am just puzzled and interested if you do not mind. Perhaps they have put in the kit jigs for another model by packaging error . Zor |
RE: help with wing jigs
ORIGINAL: Zor Perhaps they have put in the kit jigs for another model by packaging error . |
RE: help with wing jigs
ORIGINAL: Zor Its about a quarter inch to long and thats why I ask about it here I though something cant be right here with the kit being from great plane usally there kits are pretty good and instruction are very good!!! Make it 8.75 ; the difference is only 53 thou ( 53 / 1000 of an inch ). Your chord is about 1/4'' too long. That is 250 / 1000 of an inch. What is your actual chord on the drawings? What is your chord measured on the wing assembly ? What is the distance measured on the jigs ? I know you assembled the wing over the drawing but please make actual measurements. I am just puzzled and interested if you do not mind. Perhaps they have put in the kit jigs for another model by packaging error . Zor |
RE: help with wing jigs
I checked the cord and it is right about 9'' the opening on the jig is about 8 7/8'' so i notched the jig to fit. I also checked the number on the piece of stock it came out of to make sure it was for the pt-20 and it is correct. Strange that no one else has run into this with this model. OK for the 9" and 8 7/8". That was on the wing and jig. What is the drawing calling for? Zor |
RE: help with wing jigs
ORIGINAL: Zor I checked the cord and it is right about 9'' the opening on the jig is about 8 7/8'' so i notched the jig to fit. I also checked the number on the piece of stock it came out of to make sure it was for the pt-20 and it is correct. Strange that no one else has run into this with this model. OK for the 9'' and 8 7/8''. That was on the wing and jig. What is the drawing calling for? Zor Perhaps you missed post #14. I still wonder what the drawing was showing as the chord. Could you please let us know the measured chord on the drawing. Many thanks, Zor |
RE: help with wing jigs
it is the same as my wing just a hair under 9"
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RE: help with wing jigs
Thanks twostrokes
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