Building a Javron Cub

[Nathan K. Hammond]

Brackets welded in to allow a place to bolt in lead weights to adjust CG.
Bill

It would be neat if, instead of lead weight, mount an aluminum box back there. Add a filler tube at the top and a Curtiss fitting at the bottom. Then you could add and remove water ballast easily as needed.

nkh

 

[cubdriver2]

It would be neat if, instead of lead weight, mount an aluminum box back there. Add a filler tube at the top and a Curtiss fitting at the bottom. Then you could add and remove water ballast easily as needed.

nkh

You could hook it up to this and have inflight CG availability

Glenn

 

[Iflylower]

You could hook it up to this and have inflight CG availability

Glenn

Wow, a "wet tail," just like the heavies. Can lessen tail down drag and fly longer distances without bathroom breaks. What a combo.

Nate, I didn't know guys were weighting down the tail on purpose. Does it get you in much slower?

 

[Nathan K. Hammond]

It has a IO-540 on the front end and tends to run a little nose heavy. Lead in the tail was strictly for CG reasons.



The issue for us; when doing acro/skywriting, ALL the weight is forward. Pilot and 4 full 18gal wing tanks plus pyro on the wing tips for the night shows. We needed the ballast so she would fly and feel 'normal' to the show pilot. But then I go X/C with all the gear and spare smoke oil in the extended baggage which slides the CG to the absolute aft limit, making it a squirrelly bitch on the ground. If it was easy to do, I'd remove the ballast on X/C but it's not practical on our setup.

It sounds like Bill might operate the same way; heavy going in/out of a location, but want it light to play around the local area. Having the option to easily remove ballast without tools or having to 'retrieve' the weight could be a handy option. Opinion only.

nkh

 

[Iflylower]

That's Nate. I saw that plane in West Memphis getting fuel, what almost a year ago?

I kept trying to figure it cause te lines just weren't right. Is there a square oversized tail too? It sure climbed out well too.

 

[docstory]

Did you intend for the fabric to lay against the fuselage tubing at the lower baggage door? And the box at the torque tube is going to poke out at the corners rather than follow the lines normally created by the fabric stretched from the longeron over the stringer. The upper baggage door frame doesn't look like it's lined up with the turtle deck stringer either.

The cables relocated under the floor is cool.

 

[Indabush]

Thanks for taking the time to post pics Bill, very informative.

 

[Dave Calkins]

Did you intend for the fabric to lay against the fuselage tubing at the lower baggage door? And the box at the torque tube is going to poke out at the corners rather than follow the lines normally created by the fabric stretched from the longeron over the stringer. The upper baggage door frame doesn't look like it's lined up with the turtle deck stringer either.

The cables relocated under the floor is cool.

That box could be "V'ed" to make the fabric lay properly, maybe we can't see it in the photos.

Looks to me like the upper baggage door frame will lay nicely to the turtledeck stringer, depending on stringer "adjustment".

As to the lower baggage door....I'm not sure I can see the lay you see, but in the first batch of photos, the one that shows the cabin door rear latchpin hole, I believe I can see that the lower baggage door frame is stood off from the diagonal tube and the fabric will lay properly there.

 

[Dave Calkins]

I think the Hammond crew have a slick idea with the water ballast tank.

So this will have an aluminum aft-extended baggage?

 

[ron cope]

Awsome Bill .You have done such a grate job for the Supercub followers and supercub.org for this thread and thank you personallyas it is a great helpto me .Thank Again. If you are going to be on floats a lot go with the sqare air box asyou can floud the round one in real rough water/my two cents . Good Job Bill and give Jay some credit to. Ron

 

[cubdriver2]

Awsome Bill .You have done such a grate job for the Supercub followers and supercub.org for this thread and thank you personallyas it is a great helpto me .Thank Again. If you are going to be on floats a lot go with the sqare air box asyou can floud the round one in real rough water/my two cents . Good Job Bill and give Jay some credit to. Ron

I always wondered this, why do all you float guys use an air filter. I never run one when on floats and have flown in rain so hard that it was running down the floor.

Glenn

 

[Bill Rusk]

docstory - Yes the fabric will be on the tubes near the lower baggage door. I will check into the box and fabric on the bottom. The upper baggage door is just right. Jay put a stringer and fabric at that junction prior to welding to make sure the fabric would line up smoothly.

Dave - hmmm interesting idea for water ballast. I know the sailplane guys use it. Unfortunately at 8 pds per gallon it could take as much as 4 gallons back there. Might have sloshing problems and also the size and weight of the container would be issues. Fun to brainstorm new ideas though.

I don't know what the aft baggage will be yet. AL, carbon fiber, Kydex? Weight, and to some extent, appearance will be factors. One of my concerns with Kydex is the lack of rigidity. Wavy sidewalls look cheap. Once you get the Kydex thick enough to get the rigidity it is heavier than other products. It has a lot of great properties and applications, and Mike S. has done great things with it.

Ron - Thank you. If I have not done so please let me take the opportunity to give Jay DeRosier at Javron full credit. Jay is AWESOME. Some of these ideas are mine, and some his, and some are from our collaborations. Jay has been really open to working with me and that is just who he is. He is open to new ideas, weight conscious, customer oriented, and honest. In addition he is really serious about quality as evidenced by this photo of the engine mount welds...........

So...........to answer Ron, I can't tell you guys what a pleasure it has been to deal with Jay. I highly recommend him and his company for all your experimental Cub parts and kits.



Did some more weighing.

Smith tail feathers .......Vert stab - 2.5pds
Rudder - 5.25
Horiz stabs - 6.05, 6.10
Elevators - 5.45, 5.30
Total - 30.65pds

Javron Vert stab - 2.00
Rudder - 3.85
Horiz stabs - 4.905, 4.897
Elevators - 4.50, 4.50
Total - 24.652

Javron tail feathers are 6 pounds lighter than the Smithcub (I do not know about the current Backcountry). Jay did not do anything special, he just built them according to the Piper drawings. He does add a little to the inboard rib to prevent the fabric from pulling it in.

Hope this helps

Bill

 

[mike mcs repair]

wow, hadn't looked at this thread in a while, you moving along.... I wish certified had all those nice hardware kits(we have some but they are usually not what I want)...

2 things I saw might need checking...

top tube on tail box, usually is not on top of box where yours shows, or it hits bottom elevator cable.. or did you put box in different location?

on the elevator cables bellow floor thingys.. will you be adding some form of rub blocks to them?? maybe a piece of ski bottom UHMW plastic with a hole in it for cables riveted to front sides.... I would think over time those will sag and rub????

as to the kydex... with some of the new rolls/multiple grove rolls It does really add some good stiffness..... But being that you have gone to all that work to save weight, I would think bare hard 2024T3 .016 aluminum would be best for your theme, if it gets dirty you can whip out a new set from the old patterns in part of a day....
looking good

 

[Dave Calkins]

...like I said about the weight of your extended baggage......if you want to save weight, your only choice is carbon. To clean it, you can spray the garden hose back there and let it run out the scupper........of course, the fabric 'grommet' for the scupper exit in the belly fabric will add weight..

 

[Bugs66]

......In addition he is really serious about quality as evidenced by this photo of the engine mount welds...........

Wow, impressive and top notch!

 

[Bill Rusk]

Smithcub (widebody) instrument panel blank - 22.755oz

Javron (narrow body) instrument panel blank - 12.315oz

Not really apples to apples but that is 10oz. If I can find 10oz ten times that is 6.25 pounds. It all adds up.
The difference between the narrow body and wide body is not just in the fuselage. It is also in the floorboards, windshield, skylight, boot cowl, gear, etc. If you need it and want it....cool....build your perfect airplane......but if you don't need it........it does add weight.


Bill

 

[jgerard]

For extended baggage I also would suggest .016 alum but go with 6061-T6. Reason is you can bend the edge over on it's self 180 deg to give a nice radius finish and stiffen up the panel. Honestly I bet it would take years of recreational flying to beat them to crap before you needed to replace them and making new ones would be easy- heck just make 2 sets the first time!

You need the weight in the back, It's so much faster to build them from Alum, and it's cheaper!

If you don't want the look of bare alum then make a light weight cover to separate the front and rear baggage area for day to day use.

Regardless of what you use I would put 1/16" self adhesive cork tape on the frame where the floor and sides touch the tubing as a buffer.


Jason

 

[Minaki]

For those of you interested in a wide body my Javron single door, no extended baggage weighed 115.8 pounds. I concur with Bill, Jay is a great guy to work with and his product is top notch.

Jim

 

[cubdriver2]

For extended baggage I also would suggest .016 alum but go with 6061-T6. Reason is you can bend the edge over on it's self 180 deg to give a nice radius finish and stiffen up the panel. Honestly I bet it would take years of recreational flying to beat them to crap before you needed to replace them and making new ones would be easy- heck just make 2 sets the first time!

You need the weight in the back, It's so much faster to build them from Alum, and it's cheaper!

If you don't want the look of bare alum then make a light weight cover to separate the front and rear baggage area for day to day use.

Regardless of what you use I would put 1/16" self adhesive cork tape on the frame where the floor and sides touch the tubing as a buffer.


Jason

I would think that cork would hold moisture against the frame ?

Glenn

 

[Bill Rusk]

Jim

Great info. That is just what we need. Thanks for sharing.

Bill

 

[ron cope]

Hi Bill I have been talking to Jay for a long time even about you and your project and I had all kinds of ideas but aafter seeing your frame i think I will have jay build one for me just like it. I think Wayne at Backcounty is a trim motor that dose not have to have limit sw. About the supercub community being informed today or 5 year ago how in 1968 when I built the plane that I am flying that wieghtis 1100 with a o -360. The best to more Wieght of is go on a Diet.Ron

 

[Bill Rusk]

Ron

Wow, if you built an 0-360 Cub less than 1100 pounds back then, without all the lightweight stuff we have now, you are someone I need to talk to. :lol:
Well the good news is that if you get a frame like mine you will just have to follow this thread and you will be set. It is all going to be here, Lord willing.
I agree on the diet. I have lost 5 pounds since Jan 1st. I hope to drop another 10 which will put me at 165. I think it will be pretty tough to get much less than that.

Chris Hatin should be here any minute for a visit, as he is passing through town. I am looking forward to talking to the CEO of Bushwacker Acft.

Bill

 

[tempdoug]

Bill, some of the guys up here are using a thin aluminum tread plate stuff for floorboards that looks pretty neat and light and durable also look at atlees safari seat they offer also sortve neat. www.fadodge.com

 

[Olibuilt]

Was not lucky enough to find less then .060 aluminium diamond plate. Does it exist??

For the wing roots, I did let it open when modifing my plane. Not for weight saving but for storage. It's harder to seal for the rain, but I find those opening very practical for small stuff like water bottles, cellphone, satphone, headsets, cameras, etc...











Is it necessary to fabricate the steel ''leading edge form at the fuselage'' if you leave it open??

 

[tempdoug]

Oli, i like it. Also your flap setup, cool. Is that your own design? MTV if your reading this maybe you could ask Lowell where hes getting his floorboard diamond plate, and ive seen others using it. If we get the source we can find out the thickness. doug

 

[jgerard]

I would think that cork would hold moisture against the frame ?

Glenn

Felt would-Cork won't

Cork floats and it's been used by other manufactures to isolate floors from tubing for years. The Helio Courier is the first plane that comes to mind, I think the Beaver does in some areas too but I can't remember for sure. The adhesive backing is a sealed layer between the tube and the cork so no moisture would get in there. You should never leave steel in primer because primer is porous, ALL primers should be top coated with paint for maximum corrosion protection. There shouldn't ever be any water inside the fuse in that area unless you're hosing it out to remove blood or worse.... Puke! LOL

You will have way more moisture build up between the side fabric and the bottom longerons. I have seen tubes corroded right along that crotch where dirt and water collect between the fabric and the tube.



Jason

 

[ron cope]

Hi Bill . Chris Hatin must be a busy boy,Jay saidhe just picked up three frames yesterday. I live in Madrus Or about 100 m from D W . Cell #5412316323 give me call some I can tell you of S C lies. Ron

 

[Bushwhacker Air]

Had a great - albeit too short - visit with Bill. The fuse is gorgeous, and Bill's attention to detail is sure to be evident as he progresses with his build. Thanks for the invite, Bill.

Hey Ron - too busy!! Now to get them finished!! Spent 4 months aquiring our new airport and building the new shop, so Jay helped me out. Jay's work is perfect and his crew is top knotch.

 

[flybynite]

2 things I saw might need checking...

on the elevator cables bellow floor thingys.. will you be adding some form of rub blocks to them?? maybe a piece of ski bottom UHMW plastic with a hole in it for cables riveted to front sides.... I would think over time those will sag and rub????

Mike,

The system uses pulleys to route the elevator cables under and just off the tubes.



Similar to the trim cable pulleys shown here. Is that what you had in mind?



Wayne

 

[Minaki]

Just finished my interior panels made from .060 kydex. Weights are as follows.

Left front side. 1.45
Left side. 3.18
Left rear side. 1.69
Right front. 1.45
Right side. 2.05
Right rear side. .94
Rear upper bulkhead. 1.08
Rear lower bulkhead. 1.49


Total. 13.74 pounds

The Kydex is fun stuff to work with and makes a very nice interior.