Bolivia 4-Place Build

[DJ]

This will be a continuation of a previous thread that you can find here

https://www.supercub.org/forum/showthread.php?t=60535

about the rebuild of our mission Cub in Bolivia.

Things are starting to come together for a build starting in August. It surely will be a challenge with current lead times but so far all is looking good.

We have already had a number of Supercub.org members help us out. This build wouldn't be happening with the sc.org community.

Bill Rusk set us up with 2300 lb gross Javron wings with tanks and donated a big portion of their value! A friend offered to trailer them to Michigan on his way east and another friend is taking them from Michigan to Georgia for us. They will be well traveled wings...

Justin Otto is donating HD rear struts

Charlie Aileron donated horizontal stabilizers and will be overseeing me and my volunteer help on the project.

Recently an A&P friend offered to help full time for August and September.

Several others on this site have offered to help where they can.

A friend in Wasilla is building Cessna-style sliding seats for the front.

Sport Aircraft Seats in Wasilla is donating the upholstery.

Kirk Ellis, Greg Miller and Vance have helped with build details.

A friend at Lycon is helping with engine details.

And a big shout out to Javron. I bought Jay's hardware kit and couldn't be more impressed.

Catto had an 86/38 prop in stock so we didn't have to wait seven months.

And a big thumbs up for Jake at Airframes Alaska. He has helped me navigate the chaos around the 4 place fuselage and is making sure Airframes beats their deadlines. They projected end of July for a completion date and are tracking at least 5 weeks ahead of schedule!

I was able to bring a couple suitcases of parts up from Bolivia to be incorporated into the build. The idea is to do as much of the build as practical in Georgia and ship everything down as replacement parts for CP-X3112 (the Cub I wrecked).

Isaac Bedefield of God's Country Aviation and Paul Claus of Ultima Thule Lodge have offered to give some Bush flying tips for the pilot.

Bottom line...its really going to happen and the end result should be much better than before.

Any ideas on keeping it light are much appreciated.

Like Bill says....very blessed!

DJ

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[brownbear]

You’re in good hands with Charlie over seeing you. I look forward to watching the build.
Gob bless Doug

[DJ]

Anyone heard of Saint Wingtips or know where a pair might be?

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[PA-22/20-160]

PM KevinJ his buddy just took a pair off.

[KevinJ]

[DENNY]

Sooooooo!!! If the mission is going to places to provide medical evacuation to people in an emergency that is not the proper wingtip!!!!!! I am all for a big wing, BUT, it requires more and I will let others add input. DENNY

[skywagon8a]

Sooooooo!!! If the mission is going to places to provide medical evacuation to people in an emergency that is not the proper wingtip!!!!!! I am all for a big wing, BUT, it requires more and I will let others add input. DENNY

I have never heard of Saint Wingtips. They look to add about 5 feet to the span. What are the drawbacks? Extending the ailerons to the original wing tip and maximizing the travel should provide adequate roll control. The actual shape of the tip makes very little difference.

[DJ]

Ok, so the rest of the story...

Bill Rusk gave us a deal we couldn't refuse on a set of Javron wings with the 2300 lb gross. They are round tip, light and awesome. I was happy to leave them that way.

I had the chance to talk to some experienced pilots with time in the 4 place Cubs. There was a consensus that the square wing is important for heavy loads, especially over 2100 lbs. Some said it would be night and day, others said it would land 3-5 mph slower with a load.

My challenge at this point is time. I'm supposed to have this project in a shipping container by early October. I don't have the time to take the wings apart, extend flaps and push the aileron out. If someone has Javron square wings and wants to swap that would be cool. Otherwise the best I might manage is extending the aileron (leaning heavily on Charlie). The Saint wingtip slides over the tip bow and would be the quickest (maybe heaviest) solution.

Kirk has flown 4 different wings on the 4 place and likes the extended tip with stock flap and aileron fine. Paul Claus has both styles and said it's hard to tell the difference. Loni likes the extended aileron and he and Paul would both like to try bigger flaps. So there you go...its all a compromise fire away Denny

The black one has a Sullivan tip I believe and the gray one has an extended aileron with Dakota tips.

BTW if Saint Wingtips are that easy to find in the SC.org community, does anyone have a used rudder before I buy new?

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[skywagon8a]

Am I reading this correctly? The Saint wingtips only add 4" per wing? If so, forget about them. They will weigh more than the extra lift they provide. A net loss.

[Bill Rusk]

My opinion for what it is worth. I am not convinced the square tip wing, or extended wing, actually makes a difference. To the best of my knowledge no one has ever done a comparison. The whole reason I had those wings is that I intended to try to do a comparison evaluation. The problem is no one (to my knowledge) has changed out ONLY the wings (ie one variable) and done a serious flight test evaluation. The same airframe has never had both sets of wings. In every case an airplane is built, then the owner/builder lauds the performance of the square tip wing with no true comparative data. He is comparing it to a completely different airplane.
The only way to find out if there is a performance difference is to fly the exact airframe with both sets of wings, controlling the variables as much as possible, and doing a controlled flight test. Not just flying it around and saying "it flies better".
I do not know which wing is better and frankly I do not believe anyone else does either. It is just another Alaska "old wives tale" until properly tested.

My opinion only

Bill

[skywagon8a]

My opinion for what it is worth. I am not convinced the square tip wing, or extended wing, actually makes a difference. To the best of my knowledge no one has ever done a comparison. The whole reason I had those wings is that I intended to try to do a comparison evaluation. The problem is no one (to my knowledge) has changed out ONLY the wings (ie one variable) and done a serious flight test evaluation. The same airframe has never had both sets of wings. In every case an airplane is built, then the owner/builder lauds the performance of the square tip wing with no true comparative data. He is comparing it to a completely different airplane.
The only way to find out if there is a performance difference is to fly the exact airframe with both sets of wings, controlling the variables as much as possible, and doing a controlled flight test. Not just flying it around and saying "it flies better".
I do not know which wing is better and frankly I do not believe anyone else does either. It is just another Alaska "old wives tale" until properly tested.

My opinion only

Bill

Bill, read about my experiments. All done on one airplane. https://www.supercub.org/forum/showt...+wing+tip+test

[DJ]

Am I reading this correctly? The Saint wingtips only add 4" per wing? If so, forget about them. They will weigh more than the extra lift they provide. A net loss.

Neither of these are Saints...this is a measurement from the inboard end of the aileron to the wingtip for reference. The Dakotas are a few inches shorter than the Sullivans. Neither one is much longer than the original tip bow. Two full bays beyond the end of the stock aileron location. Saints will be similar. They slide over the tip bow in to the end of the aileron.

Hey wouldn't the Saints be a way to test round tip vs square on the same wing, same airplane? The only variable would be the weight of the tips themselves.

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[skywagon8a]

Hey wouldn't the Saints be a way to test round tip vs square on the same wing, same airplane? The only variable would be the weight of the tips themselves.

Read my thread in post #11.

[BC12D-4-85]

Based upon experience I'm of the opinion that it's the overall length of the rear of the wing that adds noticible lift. Lift that's more important at higher weights and density altitudes than at sea level. Best wishes for your project and services.

Gary

[DJ]

Is this a Saint Tip?

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[DENNY]

Not all Square tip wings are make the same. One STC has you cutting back the front spar to match the rear length so overall you will loose some wing length. If you are going to change what you have (now is the time to do it!) I would recommend simply splicing extensions onto both spars until you have enough room for two FULL size rib bays, not two narrow rib bays. That should push that the front spar out about 9 more inches if I remember Jays spar correctly Bring the rear spar out to match the front, end the wing with a full rib so any tip can be screwed on. Extend the aileron to the end of the wing whatever the length is a key point. If you want light get Randys Carbon Fiber tips. If anything the plane should be a bit faster with a bigger wing. Having said all of that I think the wings you have do not have the same profile as a stock cub wing on the end (only the last bay is nonstandard rib is that correct)? I think Kirk has run most every wing on a 4 place that is the man I would get advice from. DENNY

[Carey Gray]

DJ,
Check your PMs. I think I have a rudder. I'll check in the morning.

[DJ]

Turning parts into an airplane little by little.

Fuselage should arrive today!

Boy these wings are beautiful and light...68 lbs each. Fabric is going on!

Modifying a donated stabilizer to match a new Univair one.

Looking for more hands to move things along when the fuselage is here. PM me if you have some time and want to pitch in.

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[gntw]

Interestedr what the wing will wt when fabric on gas tank in lid on wing tip on
This is same wing oratec fabric p stol hangers 24 gal tank lids Dakota tips 107 lbs with landing lights installed

[DJ]

Game on.

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[DJ]

Fabric is on both wings.

Rib stitching almost done. Jodi brought the kids out and we did the first wing together. They love being at the hangar. Lots of fun. Second wing is over half done.

Tailfeathers all seemed to fit..mix of Airframes, Univair and homemade.

Fitting Cessna seat rails and sliding seats from Mario in Wasilla (AircraftSeatFrames.com).

I needed to rig the elevators to fit the seats and found out the torque tube was a mix of everything imaginable. Decided to put it back to Super Cub specs with the 3 5/8ths pedestal height. Had to modify the back end to work with no rear stick and the lower Willow mountain floor.

Jonathan has been modifying a Bearhawk rotator to work with this fuselage. It will be handy for welding and fabric work.

The hangar is remarkably comfortable for summertime Georgia temps and fall is coming so it will get better. But getting used to the heat isn't all there is to the south.

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[DJ]

Airmaster165 came down from New Hampshire to lend a hand. Nice to have visible progress.

I'm working on the Cessna seat install.

First wing is ready for color.

Next project is installing an overhead flap handle kit from Javron.

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[DJ]

One wing done in Ceconite and Aerothane. Total fabric job from bare wing to finished with VGs added 12 lbs. Started at 68 lbs with one cable and wiring for tip light. Adding fabric and glue we were at 74 lbs. Ended at 80 lbs. Plenty of smart people told me this wasn't possible with Ceconite but I guess gravity is different down here in Georgia

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[DJ]

I had some great help this week. Lots of visible progress. Interior and floor and almost done. Just final details and nutplates left to do. Baggage door and belly clean out are fabricated.

We bought an overhead flap handle kit from Javron. As always the quality was top notch. It was pretty easy to adapt to the wide fuselage.

Firewall is ready for its flange. Boot cowl is rough cut and ready for final trimming.

Instrument panel layout is on the computer and ready for the CNC table.

Tail feathers are in Nitrate.

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[DJ]

Lots of help last week

Jonathan has been the interior man. Using all the tricks he learned from Bill.
Justin drew the panel, fitted the firewall, built a beautiful baggage, door and floor tunnel with no previous sheet metal experience

We even had hard work happening in the back room from time to time


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[DJ]

Heading out for blast and paint. Should be fun to put parts on next week.

We ended up adding a lot of small stuff. Pod tabs, cessna seat rail tabs, cargo tie downs tabs, ground bus tabs, encoder tabs, parking brake tabs, elt antenna tabs, interior tabs, rear seat hinge tabs, tabs, tabs...time to move forward on other things.

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[DJ]

Fuselage is back from the paint booth. We did an epoxy prime and Aerothane polar gray topcoat. I'm pleased with it. Some are telling me it is an "in" color right now. Works for me.
Custom ELT antenna mount.

Nutplates going in. My Dad came down to help for a few days and became the nutplate master.


Stringers on permanently

I ordered stock stringers before the fuselage arrived because a friend was driving past Univair on his way to TN. This fuselage uses the larger keel stringer size for the sides as well. After some head scratching we got some aluminum channel at the hardware store that made the perfect shims.
The doorpost areas were a bit of a puzzle to solve. This was the final answer we came to.
One bonus of the smaller stringers was the ease of hand bending them at the tail.
A friend donated Cessna style seats (aircraftseatframes) that he repairs or builds new for Experimentals. I bought the cheapest new old stock rails I could find and regretted it. No holes and not spot faced for screws. The proper tool to spot face them was $100 but I found this cheap one on Amazon for $18 removed the drill bit and made a pilot. It worked great!
Drilling the pin holes with a cheap drill press was an adventure. It would rock just enough to send the bit off center. I learned to feed the rail straight into the press rather than side to side for best results. Got the job done.
Oh and the pilot and copilot rails don't match. Cheap!
These will get riveted to the floorboard and screwed down to tabs on the frame. They give 7 inches of adjustment plus we cut, bent and left them long so the seats will slide further forward for loading cargo.

Struggling with fuel line routing now. Custom trim cable came today (almost all the little pieces on this plane are custom). Boot cowl almost done. More pictures soon.

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[DJ]

Windshield showed up undamaged

Flap handle in

Fuel line routing is challenging under the floor

Hoping my plan to get all the lines into the selector works out.

trim system installed

ELT antenna installed.


If anyone sees something done wrong give me a head up please.

[wireweinie]

The ELT antenna is located under ferrous tubing. No ground plane under antenna. No room to center antenna on the ground plane, if installed. Read the install manual.

Web

[DJ]

Thank you Web. I definitely forgot the ground plane, literally. It is still in Bolivia. I'll make a new one of of .016.

I'm okay with it being off-center. If the aircraft is upside down a large, centered ground plane would be shielding the signal from vertical propagation.

"One method is to install the antenna inside the fuselage. The signal will radiate through the composite or fabric. It is important, however, to choose the location carefully. The same restrictions, not shadowing or masking the signal by metal obstructions, still apply. Aircraft structures such as tubing or ribs do not generally constitute an obstruction."

My last install of this antenna was very unconventional, under the extended baggage floor, upside down, canted outboard at an angle with the minimum ground plane. The Carbon Fiber pod was below it. Self-tested and worked perfectly.

[wireweinie]

Your ass, Cochise.

Web

[Scott A]

Maybe it is going on and off again so no big deal yet but you asked if we see anything - cotter pin is missing stabilizer yoke nut. Also fwiw Piper flips that bolt around and puts the nuts on the outside (I suspect so you can see them on preflight).

ELT antenna installed.[/ATTACH]

If anyone sees something done wrong give me a head up please.

[Steve Pierce]

Here is my ground plane out of .016" aluminum. Tabs welded to the diagonal tube that the antenna attaches to.

[marcusofcotton]

Low points in fuel system???

[DJ]

Steve your solution is what we should have done. Oh well

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[wireweinie]

Here is my ground plane out of .016" aluminum. Tabs welded to the diagonal tube that the antenna attaches to.

OK. For the rest of us; this is how this type of antenna should be placed on a ground plane. An ideal shape for a ground plane is round. The reason for this is that the ground plane is a part of the antenna system. Without one, the antenna will have, at best, a point blank range. With a correct ground plane, the antenna will transmit equally in all directions. I.e., if you install an antenna on a long skinny ground plane, the best transmit range will be in the direction of the long axis of the piece. As installed in post #35, the best range will only occur to the left/left rear of that aircraft. Although round is best, in a small rag aircraft, we reach for the best we can. The ground plane in Mr Pierce's pic shows a good compromise. Plenty of square inches of ground plane even if it's not round shaped, and antenna attached directly to it. If I changed it at all it would be to move the antenna forward to more closely center it on the ground plane.

Web

[Gordon Misch]

Here's what I did on the Exp I'm working on.

[DJ]

Maybe it is going on and off again so no big deal yet but you asked if we see anything - cotter pin is missing stabilizer yoke nut. Also fwiw Piper flips that bolt around and puts the nuts on the outside (I suspect so you can see them on preflight).

Thanks. Proper hardware in now.

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[DJ]

Windshield looks like it will fit


Jonathan has been the boot cowl expert. Looking good, nutplates installed.




Question: I want to use this same arrangement for the parking brakes. The Scott parking brakes I have are set up with a Male 1/8" pipe thread where they used to screw into the Scott masters. Is there a way to convert to female pipe thread with a AN822 elbow like this picture



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[wireweinie]

Here's what I did on the Exp I'm working on.

Just be aware that the antenna is inside a metal tube frame. This will diminish the signal transmitted from the antenna.

No such thing as 'good enough' with a piece of safety equipment.

Web