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Building a Javron Cub


Interested to hear your take on the Acmes. I didn't know there was a Acme Black Ops Gen 4 version. Thought Gen 3 was the latest?


DJ - It was about mid range.

A couple of more thoughts.....

I added a Princeton Capacitance Fuel Probe to the fuel pod. This sends a quantity indication to my GRT (I'm pretty sure it would work with other Electronic flight displays like Garmin or Dynon). I tried this system in the wing tanks but it did not work well in that application. The tanks are too flat, the probe was only about 4". The fuel pod is deeper, the probe is about 9 " and seems to be working great so far. It is nice to have that input, rather than just relying on timing the pump.

I rebuilt the oil cooler baffling, but did not have time to move the cooler off the rear baffling and to the front as I had originally planned. I tightened everything up, and used more 427 high temp sealant hoping for an incremental improvement. So far that seems to be the case. CHT's seem to be about 10 to 15 degrees cooler and should be adequate for another season.

I had trouble with one of my mags during the test flying this last couple of weeks. Excessive RPM drop but not related to just one cyl. I did a lot of trouble shooting, but finally decided it was one of my Pmags. Turns out it was one that was under water so I'm sure it is not the fault of Emag Ignition. In fact I must say that Brad and company have been truly outstanding in their support and customer service. I highly recommend the product (Pmags) and the company. I am having both Pmags overhauled and also getting a new harness just to be on the safe side.


This is the race from the main wheel on the floats. Two years ago it was new. Last year it had some very minor pitting but was still perfectly serviceable. This year the bearings and races from all four wheels are totally shot. If you have amphibs, you need to be doing a LOT of maintenance. I do not do salt water either, I can't imagine the wear and tear from that.

I purchased a set of the Acme Aero Gen4 Black Ops shocks. I have not had a chance to try them yet. But here are a couple of weights for you.

Bungee gear leg - 3.61 pds
Die spring gear leg - 4.47 pds
Acme Aero Blk Ops - 7.34

So, from bungee gear to Black Ops will add 7.2 pounds. Can't brake if you are bouncing down the gravel bar so it will be worth it, but just wanted you to know.

Hope this helps

Andrew - ya might be right. It is the latest version whatever that is. Gen 3.... gen 4.........."220 - 221 whatever it takes".....LOL

I can’t imagine a worse bearing environment that my Go-Devil long tail mud motor had, hunted in semi-salty water for 12 years and never had a lower bearing or race failure. Always used Silkolene from my Enduro Motorcycle days... it’s nasty clingy to work with but is an amayzing product.


This stuff sounds great.

I know that we are all supposed to use "approved" lubricants but I know a guy, that knows a guy, that got really tired of replacing wheel bearings; especially on tail-wheels. Said individual will now only use the good old fashioned "boat trailer wheel bearing grease" on all bearings of his cub; packed tightly. His bearings and tail wheels life span increased amazingly. Doesn't work so good in really cold weather thou.....a-bit stiff.
Jet boat drive bearings only survive because we pump grease through them at the end of every day it’s used. Stop doing that and you learn quickly how to rebuild the jet bearings on the riverbank. Sorta like trailer bearings with Bearing Buddy caps.
Texas Refinery Corp. 880 C&C. Available at Reeves- after using this grease, we went from goodness knows how many bearing changes on the fleet of private and 135 planes we maintain, to maybe 2 a year- those usually on new planes not running this grease. Also may or may not have been used and recommended by a very reputable prop shop as being far superior to approved greases(aeroshell 5, 6, 22, etc.) for greasing Hartzell props...
For what it's worth.....my friend Mark (MMR) on the site (computer researcher extraordinaire) found the bearings, races and seals at half price for what I paid sourcing them locally. Go to Summit Racing for a much better price and free shipping for orders over 99 bucks. I've used them before and had great service. I paid about 470, Summit had them for 229. But sometimes ya need it now. Ouch....

Hope this helps

For what it's worth.....my friend Mark (MMR) on the site (computer researcher extraordinaire) found the bearings, races and seals at half price for what I paid sourcing them locally. Go to Summit Racing for a much better price and free shipping for orders over 99 bucks. I've used them before and had great service. I paid about 470, Summit had them for 229. But sometimes ya need it now. Ouch....

Hope this helps


Summit's shipping is extremely fast, and reasonable
Just a quick update. The annual condition inspection and all repairs, mods, etc were completed and we are already into the new season.


Enroute through Montana. Dan Lilja met up with me and escorted me for a ways through his beautiful territory. Dan took this shot.


I spent a little time in the Idaho backcountry. After flying into JC I spent a little time in the back seat of my friends Cub as we explored and played. The trip was too short to justify swapping from floats to wheels. I will head North to Alaska in a couple of days on floats. Lord willing I will head back to Alaska later this summer on wheels.


Building is fun but so is this..........what it is all about. Using the Cub to go to cool places.

Don't give up or quit guys........it is worth it.


I see you're in the neighborhood at Felts. We're just over the hills at Sandpoint and also at Hackney North of CDA a bit. Great area for an airplane!

Fly Safe!!

I hope to keep you builders (and everyone else) motivated. I was able to spend pretty much the whole month of June in Alaska on floats again this year. It just never gets old. I was also Blessed to have a few friends join me, with a special treat this year. The Cub is doing great. On the way home I climbed to 12.5K, on amphibs, loaded heavy, to get a smooth ride and tailwinds. Love that performance. The Supercub is an amazing airplane. A few pictures I hope you will enjoy.


On Admirality Island at the Big Shaheen Cabin


Jay DeRosier, owner at Javron, that made my kit, came up and spent a week. His third summer up there with me. Jay is a pleasure to fly with and a good man.


Then, our resident Doc, that has helped so many people..... a great man and a good friend....... came up for a week of flying and relaxing.


My special treat. Docs lovely wife Julie came up for a couple of days. I am privileged to say I gave her a tour of Misty Fiords, her first floatplane ride and water landing. She stayed with us in the SE Heckman cabin for a night. I think she enjoyed it, and maybe we can get her back next year for a longer visit.


And my last guest for the season was Mark. He owns a carbon cub on floats and has done this trip in his cub. It was fun to fly together and swap notes and techniques. So three friends came up this year for about a week each. It was a privilege for me to share my Cub and this Alaska adventure with them all.


Inside the Alexander Lake Cabin. A great cabin with a nice beach for the plane, and a great view.


Swan Lake Cabin


Taken at Walker Lake in Misty Fiords. Mark is fishing way in the background.

It was a great trip this year. With the fuel pod I was able to fly non-stop from Washington to Ketchikan, overflying Canada, thus avoiding the customs hassles. It was a long flight, about 6 hours, but worth it. The weather was good this year....only a few days of low ceilings and rain. There really is not much new that you can't glean from my threads "Floats to Alaska -2016" and 2017, so I'm not going to do a whole thread.
Here are a couple of short videos of the trip. I am still working on a video of my trip with Doc and Mark. I'll add those here when I get them done.

Hope this helps

Hope this helps


Well yeah!

Give me another year, or maybe two....

I was intrigued by the nonstop to Ketchikan. I hadn't thought about doing it that way. It's only 887 miles from where I live in SE Washington.

Thanks for the dream material.

Had a fish spotter customer who would go birchwood to Washington?? direct if things went right. Belly tank, Atlee tanks, and? Made the Feds go hmmm. On wheels.

Sent from my iPhone using SuperCub.Org
Terrific Adventure!

These are spectacular videos Bill. Thank you very much for helping keep me motivated. Jay certainly enjoyed the adventure. Can't wait to see the videos of the August trip up North.
I am honored and humbled by the opportunity Bill gave me with the 7 days in SE AK. I will start a thread on the trip when I get the chance to edit some photos, as were it not for his kindness I would be looking at this thread dreaming about seeing this part of our Country.

Here are a few...

Motoring away from a cabin using Bill's amazing Suzuki boat motor. Amazingly small, fits nicely into the back of his Javron Cub.

Does this man look relaxed, or what?!

Bill reflecting on a days excursions into this beautiful area...

Julie was treated to perhaps the most beautiful first float plane flight EVER. She loved it, shown here sporting her zip-off pants (she hates these things, but they are pretty nice when it gets hot, then cooler). Her first flight was touring Misty Fjords and the spectacular scenery near Ketchikan AK.

Bill and Julie just before buttoning up the doors to fly back from the SE Heckman cabin back to Ketchikan.

More to come...

Thanks, Bill! And thanks, Jay, for the terrific kit you provided Bill.



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Fun to meet Bill and Doc Randy at PAGS, a real chance encounter. Gentlemen, the both of them. Hope to meet up again one day with some more time.

It took me longer than I anticipated but here is the video of my time in Alaska with our very own Doc. "Medical Matters" Randy Corfman. We had a great time this year, as always, and it was even better this year as his lovely wife Julie joined us for a couple of days.
.......about 4 1/2 minutes long. I hope you enjoy


Although my CHT's are under 400 degrees about 98 or 99 percent of the time I am always looking for ways to improve things. Like a lot of homebuilders I used the Vans RV6 baffle kit. This is a good place to start with the baffling but it has a couple of things that don't seem to work so great on a slow Cub compared to an RV-XX going almost three times as fast.
Here is a thread on a modification to the Vans baffling that helps.


Here are my notes and pictures on the same subject


So.......here is another mod that might help your CHT's. The #2 cyl has very shallow fins on the front. In addition, it has a seam down the center of those fins that almost completely blocks airflow from the top half of the cyl to the bottom half (in the front). Vans baffles have a ramp that directs the airflow towards the top of the cyl and the baffle goes right up against the fins. Basically this prevents ANY air from going down around the front lower part of the cyl. Jay DeRosier advised me to drop the baffle to get slightly below the seam and also to move the baffle away from the fins and to have a gap in there. After I got back from Alaska, I have been pretty busy with work and life, but I finally had a chance to modify the #2 baffle to his recommendation. Flew it today and BAM!!! #2 cyl dropped 30 plus degrees without affecting the other cylinders. Prior to the mod #2 was always my hottest cyl by about 20 to 25 degrees. Fully leaned out (lean of peak) at 2400 RPM I would see something like 1) 349, 2) 376 3) 365 4) 364 with an OAT of 60
After this mod I saw 1) 377 2) 365 3) 384 4) 385 again fully leaned out and now the OAT was 85 in the air and 95 on the ground. So #2 went from my hottest to my coolest


In this picture you can see where I put a bend in the ramp to flatten it out and get it below the center line seam in the cyl


This is pretty crude but it shows the gap (about 3/4") between the baffle and the cyl fins. Now that I know this works I will clean it up and make better baffles this winter, but it will have to work for my next trip. My #1 cyl has a HUGE ramp that covers most of the cyl and it still runs much cooler than #3 and #4 so this mod will not apply to my #1 cyl. Sometimes I think we make the baffle so tight to the cyls we don't leave enough room for the air. I understand the need to seal the top from the bottom to get differential but these two mods indicate that we also need some room around the baffles for the air to get in and around things.

I will be the first to admit that the issue of baffles is "black magic" and what works for one engine has no affect on the next one. And I have played around a little and had some mods that did not work very well or had little affect. My plenum only gave a marginal improvement, but opening up the area behind #3 and opening up the gap in front of #2 seems to have helped me. Just thought I would pass it on for you to consider.

Hope this helps

On another note.......


I have the Sandia Aerospace STX165 transponder. It needed service and the guys at Sandia were outstanding. They called it in warranty even though it is 2 years old, and even paid for the shipping. Very quick (which I needed) and always returned my calls etc. I was very impressed and recommend you consider this unit/company.

I think the airplane is ready for the next adventure. I put the Acme Aero Gen3 Black Ops shocks on but I have not had much time to play with them to report the results. So far they seem to fit and work exactly as hoped for.

Hope this helps


A couple of people have asked where I have been so I thought I'd give a little update....

After returning from a month in the SE on floats I put the Cub on wheels and had planned a big trip up through the Brooks range, and over into North Canada. That did not happen. I discovered that my registration had expired. No papers = not legal to fly. When you move you need to file a change of address with the medical part of the FAA and also the registration division. I did that, but then you must follow up with BOTH divisions to make sure they make the changes. If not you will not get the registration notices and will probably not realize your registration is expiring. Then you will discover that the FAA will not, under ANY circumstances, expedite your registration, so you will be unable to fly your airplane for close to 10 weeks. Wow.......

So.....here I was with vacation and my plan was derailed at the last minute. I did not want to waste vacation time so I had to make a new plan. (I must also add that several SC.org members that heard of my plight offered the use of their Cub.....how cool is that). On very short notice I decided to hike a section of the Pacific Crest Trail. This is like the Appalachian Trail but runs through the mountains of Calif, Oregon and Washington. I decided to hike section I of the PCT, about 100 miles over eight days. It was quite an adventure for me. I have not been backpacking since Scouts when I was about 12 years old. I did not have a lot of time to plan so the downside of that was that my pack was a bit heavier than it should have been. Most of this tired old body held up great but my feet took a beating. I guess the boots I thought were good were not so good after all. But other than that it was a great trip and something I'd like to do again. I learned a great deal and I think my next hike might go even better.


Must be from early on in the hike. My shirt is still drool free and I'd don't look like I am dying yet.


The trail is often quite rough. It is not like hiking in your local park. Awesome scenery.


They don't call it the PCT for nothing. A lot of this part of the trail would punish someone with a fear of heights. The trail was pretty strenuous for an old guy like me. I don't need to take a stress test from my doc. After this hike I am quite sure my lungs, heart and arteries are fine, otherwise I would have had a heart attack on the trail. In a few years I will not be able to do this.


I did about 100 miles over 8 days. The last two days, another SC.org member hiked in to meet up and we finished together. Mark is in better shape than I am. He was talking away while we were going uphill. No way did I have enough excess lung capacity to carry on a conversation and hike uphill at the same time. Short day was about 10 miles, my longest day I covered 17 miles. Lots and lots of uphill and downhill. This part of the trail is not level or flat. I did section "I" for those that know the trail. From White Pass to Snoqualmie Pass.


Because I did it unplanned and on short notice my pack was too heavy. Around 40 pounds with food and water. I can take 10 pounds out of that now. I had considered doing another section right after this one but it was in the middle of a heat wave and my feet were in pretty bad shape. The boots I thought were good were too small and did not allow for normal swelling when covering this much rough ground. I discovered your hiking boots need to be a size or two larger than normal to account for swelling. Mine were sized for normal and were fine for a few miles a day but not for 12 to 15 miles a day over rough terrain, uphill and downhill. And it was a little less fun with the heat. Hauling a 40 pound pack uphill in 95 degree temps is not so much fun. Had the temps been more normal for 5000 foot elevations I might have done the second section even with messed up feet.
But....I learned a lot......and I will do some more of the PCT in the future. It was a good experience.

Here is a long video of the trip (14 minutes)

Then after this trip I did another "first" for me. I'll do that report in a day or two. It involves our good friend and SC.org member.....DW.

Hope you enjoy

Bill, Thanks for sharing. Glad you are still fit enough to carry 40 lb!
Had dinner with DW recently. You got wet! Can’t wait for the report.
if and when you do wings, im hoping you let everyone be involved. havent been into a wing for 15 years, would be really neat to see, new and improved.

Since I could not fly my Cub for a while I got after another bucket list item. Our good friend and fellow SC.org member DW has been doing a lot of scuba diving of late, and in fact at 69 years young, got his instructors certification. That is really cool folks. It is NOT easy to do when you are in your 20's...but to pull it off at 69 is a world class accomplishment. DW took me on a dive trip to Roatan Honduras. It was a fantastic week of diving.
This is definitely something I will do again. The last few years have been quite a whirlwind for me as I try to catch up on things that were not so easily accomplished in my former life. I have been Blessed to go canoeing, flying in Alaska, fishing, skydiving, hiking, snow skiing, and now scuba diving. Diving is definitely something I will do more off. Lots of fun. Thanks DW!!


DW is just as good at diving as flying. He is also a great instructor. While we were on the dive trip he managed to work with me and signed off on my Advanced Open Water Certification. Thanks DW!


We stayed at the CoCo View Resort on Roatan. This is an all inclusive dive resort. Spent a week there and managed to get in 21 dives, including a night dive that was super cool. With DW's help we managed to find an octopus. Very cool!!


Ready to head out


Apparently DW is part bird and part fish. He is very comfortable under water. An amazing ability to remain totally motionless and hover while using very little oxygen


Standing on a ship wreck we explored.

OK....so here is the video. It has some underwater shots and video as well. Its about 3 1/2 minutes....so not too long.

Hope you enjoy



Time to get back to flying. The annual was pretty easy this year, although I did rebuild all the retract systems in the floats. Did a little baffle work, and a few other items. If I have time I will do a thread on this trip but here are a couple of teaser photos. The Javron Cub is back doing just what I built it for. Useful load on wheels close to 1200 pounds, and fuel at 68 gallons (with the fuel pod) makes adventures like this possible.

That is Denali under the wing

That is Russia under the wing

That is the Arctic ocean under the wing

Hope this helps (motivate)



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