Jungster 1 & 2 aircraft

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Littlemoose

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Nov 1, 2021
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I have the wing drawings with dimensions so the PDF is very useable in this case. Are the center section ribs essentially the same but cut at the trailing edge or is there a different profile for these?
 

Fighting 14

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Sep 18, 2021
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Appears that if you print it at 100 percent you may have a mosaic which you can piece together a pattern of the rib. Dominic will have the correct explanation.
 

Fighting 14

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Gap strips added to F-14. Full power run-ups today. Weather still lousy. Able to raise the tail at full power while holding brakes. Felt good.
 

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Dominic Eller

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Hi guys, I’m listening 😉 just been caught up in the turbulence of life a bit 😂
I hope the wind backs off so you can get flying F14th!
I’m curious if you remember the incidence you set you wings too? Did you use the original fittings ? Or did you have to make new ones?
I needed to re make a few fittings the first time I rigged it as the lower wings where at quite different incidence. I also didn’t know then I had a longeron repair to do and could not see that the cockpit longeron had a slope going up aft so I had leveled it a little nose up about .5 deg.
I’m re rigging again now with the finished wings, new cabanes and repaired front upper longerons and have needed to re make a couple of fittings to get things right.
I’ve got the sweep to an with in an 1/8” of each other, I think that’s good enough?
The lower wings are set at 3.5 deg dihedral with +.5 deg incidence and the top C section sits at 0 but the wing panels sit and +.4 deg. The planes give a range of incidence :lower +.5 to +1 deg and upper 0 - +.5 deg. I think I’ll stick with this and if needed I can make the rear cabane adjustment longer and if need be can make the trunnion they attach to a little longer to keep as much thread in the fork as possible. How does that sound to those in the know ?
and left dihedral is at .9 deg and the right is at 1.5 deg. I’m making new front struts so I can correct that and my rear struts I have made adjustable too.
I’ve made some tubes with rod ends to put in place to hold the upper wings at the correct dihedral while I make the new front struts, I think this should work?

What I don’t want is to end up with something that flies very tail low due to incidence being set too low.

I think I’ll have ended up building a bunch of parts 3 times over bu the time I’ve finished !

Little moose, post some pics of your model for sure 👍 Here is some rib dimension pics with dims.
And some general other pics of my ramblings 🤪

B16C40E3-D38A-4940-8B39-D0FC98826286.png image.jpg image.jpg image.jpg image.jpg image.jpg
 

Dominic Eller

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May 16, 2019
Messages
264
I have the wing drawings with dimensions so the PDF is very useable in this case. Are the center section ribs essentially the same but cut at the trailing edge or is there a different profile for these?

Yes just cut to fit,
A print shop should be able to print that full scale. Just take a ruler and check that it actually is correct, the printer guy did a few adjustments of my PDF plans until we had correct dims.
 

Fighting 14

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Sep 18, 2021
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Sounds like you are fine on incidence. I know what you mean about flying tail low. Had a friend with a Hatz biplane and it flew very tail low. Mine was all set by the previous builder. I flew it all the way from East of Atlanta to Gainesville Texas, and it flew fine other than the lateral rigging was horrible. My wing tips are what were on it. I think a lot of people take artist's license. I replaced two because they were just gross. Mine are glass over foam. Back to incidence. Using the cockpit longeron for a reference my upper and lower wings are about zero degrees using the bottom of the wing, but angle of incidence is measured from the chord line which runs from the center of the leading edge to the trailing edge on the Jungster rib. So looking at the rib and eyeballing it with a protractor it looks to be about 4 or 5 degrees. That should be the actual angle of incidence. Most light airplanes use around 6 degrees and aerobatic airplanes less. So 4 or 5 degrees sounds about right and we should be fine. So with the bottom surface of the wings parallel to the upper cockpit longhorn the effective angle is roughly 4 or 5 degrees. I think you are probably fine. Your pics are great and I love the varnished wooden leading edges. Mine are aluminum. Like I have said your woodwork looks to be first class. You will be flying soon. Fabric goes fast. I rib stitched mine to the ribs so that took a little more time. I felt a little uneasy about only gluing the fabric to the wing. Nice to have you back Dom!😁
 

Fighting 14

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Sep 18, 2021
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One thing I have noticed is that as the wood dries and shrinks on these wooden airplanes, you have to get to all the bolts and nuts holding the control hinges and brackets and tighten them up. I am having to do that now. So as a word to the wise leave yourself an access hole in the fabric or wooden skin to get to these points without having to tear things apart later. The wood WILL shrink and the fittings WILL loosen up. ( Something to look for and preflight carefully ):( The aileron hinges are behind the rear spar so leave yourself access. Make sure you can get to both sides of every control hinge.
 

Dominic Eller

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May 16, 2019
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Very good point F14th, I’m considering options to capture the nuts on the inside so they can kept tight with out internal access. One idea I have is to use locking nuts designed for high heat application and tack weld them to washers and then epoxy and screw (maybe just one small screw) the washer/nut to the inside ply plate.
In the case of the ailerons where two nuts per hinge is used I’m thinking of making .049 sheet rectangles to weld the two nuts to…… still thinking on this whole concept. Anyone see any problems with this?
 

Fighting 14

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Sep 18, 2021
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340
I found a pic of the Jungster I used to fly. It was on the net. Different engine and looks nothing like the airplane I flew. Also the double wires on the tail are missing. Different cowling, different fuselage profile. So I wonder what happened? It was wrecked and the N-number is now on a different airplane. Hmmmm.
 

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Dominic Eller

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Re the chord and incidence. I read in D J Brimm’s aircraft maintenance a circa 1940s book. That generally with flat bottomed and under-cambered airfoils the lower surface is used to measure incidence ( and actual chord with semi symmetrical )
I always wondered if Rim intended that with the .5 to 1 and 0 to .5 numbers.
It’s good to know what your values are F14th 👍 like sooo many things 1st time round with this game , you I just don’t know what you don’t know regarding what isn’t spelled out in the plan.
Lots of learning going on 🤪
 
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Dominic Eller

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May 16, 2019
Messages
264
I found a pic of the Jungster I used to fly. It was on the net. Different engine and looks nothing like the airplane I flew. Also the double wires on the tail are missing. Different cowling, different fuselage profile. So I wonder what happened? It was wrecked and the N-number is now on a different airplane. Hmmmm.
That’s great find! Looks like they lowered the rear turtle deck quite a bit, was it like that when you flew it?
 

Fighting 14

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Sep 18, 2021
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That would be true if the leading edge did not come up before reaching its' furthest forward point. Lot of TLAR using the plans. As we used to say, "Designed with a micrometer, laid out with a piece of chalk, and cut with an axe." If you look at the defined chord line for the Jungster airfoil you will see it does not follow the bottom of the wing. It runs from the center of the leading edge (furthest forward point) to the trailing edge. I don't remember it flying tail low like the Hatz did. It was not particularly fast. Like 90 mph to about 105 mph. Super Cub like cruise.
 
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