Jungster 1 & 2 aircraft

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Dominic Eller

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FWIW, I use a wedge pack in an S-1S, also hoping for a bit of a seat back recline effect. The effect, for me, at 6’ 2” is almost non-existant. Were I to look for a different parachute, I would look for a flat that would pack thinner that the wedge does.


BJC
I should have clarified that there is enough room for a wedge of foam about 2 1/2” thick at the bottom tapering to nothing. This and the wedge pack gives some recline / lumber support. Feels a lot more comfortable than the original seat position and I think the sight picture being lower in the cockpit is better. Feels nicer IMO being in it rather than perched on it too.
 
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Dominic Eller

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Very clever and well done. Without my seat pack my head is about the same as yours, even with the turtle deck and back of my head against the headrest. Eventually I may leave the parachute out. I really need a square chute up here. Landing under the small round canopy that I have will probably really hurt at this altitude, and then you have the wind to deal with, and no riser quick releases. Ouch. I am using a small inflatable camping pillow behind the small of my back for lumbar support. The cockpit is definitely tight. I will be curious where your CG lands. Which prop are you thinking of using? I told you that my CG is about at the aft limit. I am going to run another weight and balance check with half a tank and another with an empty tank just to verify the fuel tank centroid position noting any fore or aft change in CG. On another note, where do you get your aluminum? I went to using carbon fibre for the gap strips because the price of aluminum and the shipping charges have gotten so high that I can get rolled carbon fibre cheaper. I have not used it before, but hope I can get a better lay-up and bend around the leading edge than I can with aluminum. It will be lighter I think. And I need to make a fairing for the vert fin horizontal juncture. I will try to tape the area and lay up over that using peel ply. Fingers crossed. I usually do things three times before getting it right. Winter is nipping at us so it may need to wait.
I haven’t needed much more than scrap aluminum so far. But I have an aircraft restorer close by that helps out with things like that.
If I end up going the flat 4 engine I’ll most likely fix up and use the existing cowl and fairings etc..
Interesting idea of extending the tips a little, I’ve made some foam plugs to pull fiber glass tips off. Not sure how grunty the tip attachment would need to be if they where made large enough to make a difference…. Would be embarrassing to lose a tip or two!
Planing on having a custom Brent Thompson prop made. They have an amazing track record of getting the best out of any engine / airframe combo they design for.
I’ll wait until it’s pretty much finished before working out the engine mount length to get the CG as good as I can.
Might end up with a bit of a long nose if I can’t keep the weight out of the back…..
 

Fighting 14

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I put wing tips on my Yak 52 at one point. They did nothing to change the cruise speed or stall speed, but there was a noticeable change to the roll rate. Slower roll with the tips. I'd guess about 5%. So adding a big tip to the Jungster may not yield much. I had to leave my Jungster pretty much as it was originally built since it has already been issued an Airworthiness Certificate. But since you will be issued a new Air Worthiness there in N.Z. you have some lattitude to make some small changes? If I had had the lattitude, I would have mass balanced and extended the ailerons so they matched the same geometry at the tip as the the original Bucker. Same aileron all the way to the end of the wing as the FW-190. I would have put another 12 inches on each wing panel also. Might have made the lower wings unswept to move the CG forward and lengthened the fuselage and redesigned the seat. But, it is what it is, and what I am talking about is a different airplane. Is your seat back straight up and down or does it incorporate the slanted back? Mine slopes. You can see the angle by looking at the cockpit rear edge of the cockpit door panel. You probably already noticed. Without a bucket seat or a bucket seat back like the Blanik it is pretty hard to find a parachute that works well in the Jungster. Any kind of back pack puts me too close to the panel. I am comfortable with the National. But I still need a pad in the small of my back. Probably not going to the airport today. I'll probably get there tomorrow and will check the deck angle.
 

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Fighting 14

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How hard do you think it would be to extend your ailerons at this Point? If you could do that and add more tip than I added to the YAK, you might see some real gain. The YAK tip capped off the end of the aileron and I think that is what affected to roll rate. The additional span added was minimal. This is just theoretical so don't mind my rambling. Let me see if I can dig up a pic of the FW-90 and Bearcat. That is the configuration of the aileron I am talking about, rather than having it capped off by the tip.
 

Dominic Eller

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I kept the seat back straight, I didn’t want to open that can of worms and extend the re build time more than necessary.
Also by keeping it straight I didn’t move the CG back more. With the new lowered seat I get to have my bum more forward too, that and removing around 10-15 lbs of instruments and panel should help a little.
Jerry Kerr mass balanced his ailerons and said they where lovely and light. But it did take I think 5 lbs of lead in each!
I like the idea of light controls but not at the 20lbs of extra weight in a design that has no flutter incidents below VNE.
I might experiment with aileron spades…. But I’ll seek aerodynamic advice on that before hand.
I have read before and seen examples of Jungster 1 gaining roll response by fairing the lower struts and adding gap seals on the top surface.
That could be an interesting experiment for you after initial flights, shouldn’t be too hard to tape a few crude fairings on and see what it feels like.
In post #32 I linked some vids of a chap spinning and general Aeros in a white and blue Jungster 1, it has some fairings on the lower struts you could check out.
One of the must have mods for me is extending the cockpit tension member that the instrument panel mounts to forward to the wooden crossmember.
This makes negates having to contort sideways to get out, something that could prove fatal in a bail out situation.
It requires a little beef up of the gussets but is worth the small weight increase in
my mind. It will also sit the instruments at a better distance for focal length change when swapping outside view for glances at the instruments.
 

Fighting 14

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Thanks, good idea for the ailerons. This video has a second part which I am anxious to see.
. It is about flutter testing the Gee Bee Z.
 

Fighting 14

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Here is the angle of my A/C sitting on the the gear, 14 degrees. Weighed it again today and the empty weight is 715.5 lbs. The tail wheel weight in a 3 point attitude with me and parachute in the cockpit (178 lbs) is 150 lbs. My chute weighs 14 lbs.
 

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Dominic Eller

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Thanks! 14 deg, I’m sure ours sits lower. I’m a little curious as to what the flat bottom of your aerofoil sits at too?
She really looks good! I was imagining when it’s recover time for the Rans what she would look like in Fighting 14th livery, could start an international squadron 😂
 

Fighting 14

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Sorry, I remember that is what you asked for. I will check the angle of the bottom of the wing. Instead of working on the Jungster I flew the L-13AC today. Getting late in the year and the thermals were not terribly strong. But the wind was down the runway and not terribly gusty at about 15 knots. Lotta sink. Tomorrow we work on the Jungster.
 

Fighting 14

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The wings, top and bottom are 14 degrees at the mid inboard section, and outer panel is 12.5 degrees measured just inboard of the outermost rib. Preparing to lay up carbon fiber wing gap fairings.
 

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Dominic Eller

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Did you rig the washout in or is that just how the original rigging was set up?
I’m thinking of rigging for constant incidence along the whole wing and see if it needs any washout added. I figure if it isn’t tip stalling badly at the on set of the stall, then the less washout the better for snap rolls…..I could be wrong in my thinking there…?
 

Fighting 14

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I think the wing panels were built with the wash out. I rigged to get some additional washout on the left side because it has the N strut adjustment and it was farthest out of rig. You could see it by standing in front of the airplane and looking. The protractor confirms what you see and I used it to fine tune. Make sure the hangar floor is level and set your tire pressures the same. Then hopefully you end up with a level fuselage and center section. I learned how to rig when I restored/rebuilt a Ryan STA. The right side wing rigging on this Jungster just fell into place without anything more than eyeballing, measuring tip to floor distance and outer panel angles. There is not a whole lot of adjustment with the single landing wire. But it seems I was able to get them all at like angles and my flying and landing wires seem to be at about the right frequencies. Did you ever see a tensionometer spec for the wires? I have not. The old timers that helped me a long time ago pretty much tuned the wires by ear. You want them tight but not overly so. If the frequency is too high (too tight) they will hum in flight and you will know it. It's a lot like trimming an R/C and tuning a guitar. Try to get all the slop out of the controls. Having no mass balancing, some friction in the control system circuits is probably a good thing. Then after flying, make small adjustments until you get the rigging perfect. Check out the Kermit Weeks Flutter Test video part 2. It is very interesting.
CEO
 

Fighting 14

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I'll let you know about how snappy it with the washout after I fly it. Do you know how to do a vertical reverse? It is a good way to assess how snappy the airplane will be without ending up on your back. It was a WWI maneuver to rapidly change direction. It's a half snap over the top initiated from a steep turn. We need to look and see if the Jungmeister incorporated some washout?
 

M Clarke

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Cowling is going to look good ! Man that’s a lot of work sanding! Are you wings finished? I’m
Looking forward to seeing them on.
Cheers for pics of tail wheel set up.
32” gear is long! I bet you don’t see anything 😳
Previous owners have flown my Jungster a couple hundred hours before I bought it as a firewall forward project. I thoroughly inspected my wings and they are in great shape. They were extended 2 feet on each side at the roots. I’ve had them on and off a couple times.

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B6D8ECD5-D402-49E4-98D4-92C4992E9236.jpeg
 

Fighting 14

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Took me eight years to rebuild the Ryan and I have been working sporadically on this Jungster for about 15 years. Seems like as you get down to the last items it takes much longer, but you pick up the pace because you know you are about done. Keep plugging and you will make it.:)
 
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