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Building a Javron Cub

Greg,

You doing that for a living and only charging $160????

So that would be $20 in bits, $100 in set up and tear down time, $100 in time to do the drilling, and then postage...

Yup, make lots of $$$ doing this stuff.

I do it for friends just to keep practice. But truthfully, it takes more time to do that work than one can ever get paid. Like building your own plane...

of course, who needs brakes anyway?
 
Folks

I am so sorry about this. I DO NOT FEEL RIPPED OFF. Greg was great in every respect. He was quick and professional and for the work done I feel the price was very reasonable. Like George says, no way could I have done that in terms of time or money. I was led to believe by others (NOT Greg) that the weight savings would be greater so I was surprised. I just made the post so folks would know the facts and thus be able to make informed decisions rather that hearing things like "well I know a friend of a buddys' second nephew that saved 3 pounds drilling his rotors". I did not mean to impugn Greg or anyone else. Greg....please please understand I was not implying I was in any way unhappy with the work you did or the price. I can not tell you guys how bad I feel about this.

Bill
 
I agree with Pierce, I don't think Bill's post implied he felt he was ripped off. Just that the law of dimisinishing return had kicked in. We had a family friend set an altitude record in his Long Ez about 15 years ago (35,000 ft +-) and during the planning for the altitude record, he was pulling all kinds of "extra" items out of the Long when he realized the greatest weight savings he could make was a diet!

My wife and I have lost over 50 lbs since January of this year and that weight savings has a very high return on investment!

James Smith
 
Bill, Sorry for making my reply as I am not interested in making you feel bad. I know that those were my words and not yours (ripped off).

Sorry

Greg
 
Sometimes the internet and written words (without all the inflection, body language, and extra explanations) can sure make communication difficult. Greg, next time I am out your way dinner and beer is on me. We will laugh and talk about saving weight, flying cool airplanes, and landing on gravel bars.

Bill
 
Greg is the house done so you can get back to flying? Haven't seen you down on the river in a while.
 
Hi Bill:
What is your current thinking on Doug's double slotted fowler flaps on this build?
"Doug

Please sign me up for a set. I see a new set of wings in my future. I will see you this weekend with deposit in hand!

Bill"
 
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My wife and I have lost over 50 lbs since January of this year and that weight savings has a very high return on investment!

James Smith



Cubpylut
Congrats on the weight loss. Fifty pounds will cover for a lot of aluminum or 4130. Making sure we can still fit in our old military uniforms we wore at 21 will do great
things for our cub's performance.
 
Well.....Lord willing I am supposed to travel North on Jan the 18th and pick up all the weldments. Basically everything except the wings. It took a little longer than I hoped for but I am still very pleased with all my transactions with Jay and Javron. I know he has hired three welders since I ordered my kit as he is ramping up production. He had several kits in front of mine and he has at least 13 fuselages behind me. So get ready for lots of post and pictures.

Engine - After GREAT consideration and lost sleep I have decided to go with the 0-360 series. It will cost about 18 pounds on the nose not including the prop.
The deciding factor was a recently surfaced memory of my ill fated trip wherein I discovered the ABSOLUTE ceiling of my cub (loaded pretty heavy and on floats) was 10,200 feet on a cool day. Approaching Great Falls, Montana I could not go over the ridgeline but had to go South through the Rogers Pass then back North to Seeley Lake. I did not have the option to go over the mountains at 9500' because I was falling out of the sky at 10K. I think the 0-360 will help in that regard, and though I much prefer the look of the traditional round wingtip, the extended wing seems to really "work" at the higher altitudes and weights, thus I am rethinking my wing choice as well. This is, for me, a big part of the mission for the airplane....floats and mountain lakes. I will still be shooting for a empty weight of 1100 pds. Gonna be tough but if you can't handle the heat ........

Mark Rusche (MMR here) has been over lately working on his PA12 and last week we did a little more weighing.
On the Smithcub I used 1/16 2024 and contact cemented a heavy tweed fabric to it to do the interior. I really liked the look and "feel" of this but it did add some weight.
Here is a picture

Interior2.jpg

1 Sq ft of 1/16 AL weighs 3.75 oz
plus cement weighs 4.72
plus fabric weighs 6.75 oz total
So 6.75 oz per square foot of interior panels. If we figure (roundly) that the baggage compartment is 2'X4' on the sides and 2'X2' on the back we get 20 square feet of area = 8.437 pounds in Fabric, or 5.3 pounds in .040 Kydex. So I can save 3 pounds in the baggage compartment area if I use Kydex. And even more if I use .028 Kydex. I like the look and feel of the fabric interior and will probably still use it in the cockpit area even at the expense of some weight. I know that no interior is the lightest and that works for some folks, (cool, go for it,) but for me I prefer a little more refined interior. But nonetheless I just found 3 pounds.

So that is where I am......waiting for the 18th.......like a kid waiting for Santa........

Thanks for asking

Bill
 
P Mags

I thought these looked like the ticket till Bob B. had one quit on his O-375 Cub with less then 80 hours on it. Opened it up and several capacitors fell out. They had broken / fallen off the main circuit board. P Mag said they thought it had gotten too hot. I looked at it and it seemed to me like heat was not the culprit.

The capacitors are about the size of a pencil eraser. The capacitor legs go through holes in the circuit board and are soldered on the back, printed side of the circuit board. They are then "bedded" in what looks like hot glue to stabilize them.

It looked like the "glue" had broken free of the circuit board and the capacitors shook back and forth (O-375) till their legs fatigued and broke.

Unless P-Mag has figured out how to fix this so it will NEVER happen again, I'd get my spark else where.

Take care,

Crash
 
Hi Bill,

Thoroughly enjoying your thread! Thanks for posting the weight of the fabric covered aluminum!

How much weight do you guesstimate powder coating the fuselage added (or saved) vs just using a good two part epoxy primer/sealer? You did go with powder coating, correct?

Thanks,

Tom
 
That is unfortunate on the P-mag. I will be installing one on my right side and will run 1 Slick and 1 Pmag. Supposed to get 80% of the benefits. If my pmag fails still have the left Slick with impulse coupler.
 
Engine - After GREAT consideration and lost sleep I have decided to go with the 0-360 series. It will cost about 18 pounds on the nose not including the prop.
But nonetheless I just found 3 pounds.

That means that the engine is only going to cost 15 pounds now.

I feel your excitement Bill!
 
Crash (and others) - Don't know when that Pmag was manufactured. In the first couple of years there were some problems; however, in the last few years the Pmags seem to have excellent reliability. Here is a link to the RV forums where there is a lot of good info. Like SC.org but an even larger group of folks. It is a great resource to search for info on common items like mags, alternators, instruments, paint, etc. For the other builders I recommend you put this site in your favorites folder and use it often. It is a great resource.

http://www.vansairforce.com/community/index.php

Tom - I do not have a weight for primer and paint but my understanding is powder coat adds 3 pounds. My fuselage will be weighed before my powder coat (primer powder coat followed by topcoat) and that will give us a more accurate number at least for the process used on my fuselage. Thanks for the encouragement

Pete - things I am doing to reduce the weight of the firewall forward. Tapered fin cyls, Pmags, skullcap spinner, B&C 8 amp (so removing alternator pulley and lightening ring gear), thrustline built in (royality will be paid to Mark E.), no swing out mount, Titanium Firewall, Electronic master solenoid, AL cover plates, Carbon fiber cowling, battery?, Catto prop etc.
When all is said and done it will be lighter, firewall forward, than the original 0-320 with the heavy generators, starters, and Borer prop. Lots of folks feel the original Cub is the benchmark for performance and I do not disagree. Mine will be lighter than that, firewall forward. But all these things can now also be done to the 0-320 so I will not be lighter than an updated 0-320 package but I will be lighter than the original 0-320 package. I will end up near the forward CG limit when empty which should work out OK as the CG will be further aft when loaded for trips. More on this issue later.

Hope this helps

Bill
 
Bill,

a forward CG is easy to fix, aft is hard to deal with. For a forward one, just put your address book with all the folks you need to visit in the back, and it will be cured!:p

Keep up the scale work, I will buy you some batteries when I see you next, I am following your lead on some of the weight stuff!
 
I've heard elsewhere that if there isn't a blast tube directed onto the PMag, it'll overheat. Soon as I get the bucks, I'll be ordering a PMag. Until then, I'm in the process of converting my Bendix mags to 8.5 mm super condutor auto plug wires. Plan to use NGK AB6 and AB-7 spark plugs which are supposed to be the correct heat range/size and supposed to screw right in in place of REM38 & REM40. We shall see...
 
I've heard elsewhere that if there isn't a blast tube directed onto the PMag, it'll overheat. Soon as I get the bucks, I'll be ordering a PMag. Until then, I'm in the process of converting my Bendix mags to 8.5 mm super conductor auto plug wires. Plan to use NGK AB6 and AB-7 spark plugs which are supposed to be the correct heat range/size and supposed to screw right in in place of REM38 & REM40. We shall see...

I have over 1000 hours on my Pmags....they are the current (and last?) version 114. The internal electronics will not tolerate continued high heat (over 230-250F) for very long. Blast tubes are a must. High oil temp (over 220F) and no blast tubes will eventually cause them to shut down. Manufacturer says they shut down at 250F internal temp to prevent permanent failure.... and begin to function again when they cool down. Highly modified engines that run hot are not a good fit for the Pmags, imho.

I run the auto plug inserts along with NGK BR8eix iridium plugs (http://www.amazon.com/NGK-BR8EIX-Iridium-Spark-4-Pack/dp/B004RT4PMO) . The non iridium last about 40-50 hrs before needing to re gap...and another 40-50 and will need replacing. I got 450 hrs out of my last set. I have 9.5 to 1 comp so a hotter (BR7) plug is not advised. The BR9 is too cold.

Lou
 
Lou - Thanks for the info.

Any noticable performance difference between new iridium & new non-iridium plugs?

Thanks,

Tom
 
Bill,

On your wing choice: I think you'll find that the extended squared off wings also work better getting off the water when on floats. Wing and power are what make float planes launch.

MTV
 
Maxtorque - Yes I have also heard that blast tubes on the Pmags are good but I kinda feel that is true of all mags. Heat and electrics, of pretty much any kind, don't go well together. I had blast tubes on my bendix mags on the last plane and would put them in again on any mags. I have heard that heat has been a problem on the lightspeed ignition as well. So..... cool all your ignition systems.

Thanks Mike. That jives with other info I am getting. I had a nice visit with Kase yesterday. As you may know he has flown a LOT of cubs and I think just about all the Dakota wings, slots, slats and everything else, and usually in the mountains. He had an opportunity to fly with a friend and the only difference between their planes was the extended wings. About the same weight and both with 160hp. He said up to 3000' there was pretty much no difference in T.O, climb, or landing. But when they got to 5000' there was a noticeable difference with the edge going to the square wing, and at 8000' the difference was huge in T.O and also climb. 8000' seems like a lot but as you know you can see 8000' density altitude pretty easy in the mountains in the summer.
The feedback I am getting is that the standard flap with the extended aileron is the best combination. The extended flap and standard aileron seems to be a little sluggish in roll. Plus with the standard flaps (extended into the fuselage) it will also make it easier to convert to the Keller flaps in the future (probable future upgrade).

Thanks for the feedback

Bill
 
Alierons to the wing tips, which ever tips you choose. round tips are very nice to have in brush, but you do get more lift form big wings...

I like round tips!
 
Bill, are you going with a square or round carb heat box and square or round lower cowl airfilter? Now that were into squares and rounds.
 
Bill, above you mentioned a number of things you were going to do to cut down on weight FWF:

"Pete - things I am doing to reduce the weight of the firewall forward. Tapered fin cyls, Pmags, skullcap spinner, B&C 8 amp (so removing alternator pulley and lightening ring gear), thrustline built in (royality will be paid to Mark E.), no swing out mount, Titanium Firewall, Electronic master solenoid, AL cover plates, Carbon fiber cowling, battery?, Catto prop etc."

If you are able, would you please provide info on the 'thrustline built in (royalty will be paid to Mark E.)'?

Also on the electronic master solenoid?

Thanks for all your efforts -- your telling about them are of great benefit to those of us following in your footsteps!

Andy Mutzig
 
Tempdog - Round, like my last Cub. Supposed to flow more air. I don't know if it has ever been tested on a dyno so take it for what it is worth.



Andy

Mark Englerth came up with the idea to change the thrustline of the Supercub. He invested a considerable amount of time and money to get the STC for this VERY worthwhile modification. With a certified cub, in order to be legal, you must get the Thrustline Kit from Mark with the associated STC. The spacers used to push the bottom of the motor mount outward and thus the front of the engine up, are beautifully machined and weigh about a pound each.
Some of the experimental builders have incorporated his idea by building a motor mount which includes the new Thrustline angles. This is lighter and better but it cuts Mark out of receiving compensation for his idea. I can't speak for all the Supercub Kit companies but I know that Javron pays Mark a certain agreed upon amount for each motor mount that incorporates Mark's Thrustline modification. Here is a link to Marks Thrustline website.

http://thrustline.com/expect.htm

Here is a link to a new Master Solenoid by Ztron Labs. This will save 11 ounces from the standard master solenoid.

http://www.ZtronLabs.com/products.php

Hope this helps

Bill
 
I heard that the Breaden Cub had some really high engine temps once some engine instruments were installed. Wouldn't let the failure of a one off, highly modified experimental make up my mind. Talked to a lot of folks running them without any problems.
 
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