Building an Experimental PA11

[Dan Gervae]

Pretty sure it’s on my thread somewhere.
They definitely do not use a front strut on the rear strut. Without looking through my thread, I’m pretty sure that they are lighter than the heavy duty strut set, but a little bit heavier than the original strut set.
Bill

I talked to Jay...that's what he said....They are made for the 2300 gw so are maybe a little overkill for my 11.

[Dan Gervae]

Have you checked with Carlson in Ohio for al. strut material? They are a good small company to do business with.

I see on their website they offer some end fittings....but not sure if they have a setup for cub strut forks/??? Maybe I will call them. Airframes struts are expensive, but there is a $500 discount for Experimental. https://carlsonaircraft-extrusions.com/aluminum-shapes/

[TurboBeaver]

I purchased a set of Aluminium struts from Javron in Dec, and to clear up a bit of confusion on this weight of strut issue:
#1: Jay told me on weight, the only reason for Airframes struts being lighter was THEY stock the 'smaller rear struts' and he does NOT. Because he just doesn't sell enough strut kits, to justify stocking both profiles yet.
So the only reason Javron's struts are 2200lb rated vs 1800lbs is that you are running front struts, on the rear like a Maule.
Hence the over all weight increase over Airframes listed weight; of two fronts and two SMALLER rear struts. So I am guessing if you weighed 4 Airframes FRONT struts; the weight would be the same as the Javron's weight! And of course if you were to install all 4 Airframes front struts, you would again up the load rating to the 2200lbs. Javron's 4 Aluminum struts weight: is pretty similar to a standard sealed strut set that are in both profiles, but they are lighter than the new HD sealed struts. Not sure how Jay came up with two of the "smaller REAR 'aluminum struts"for Bill Rusks kit...????? Guess that will have to remain a mystery for now. Here is a stock photo of the Javron struts; and rest of the kit. Very nicely done like all of Jay's stuff!
Hope this helps
E

I am sure there are some folks in Alaska/ Northern Canada that have had their rear struts fail when overloaded with snow and classic rear strut kinked; that may have benifited with extra 400lbs of load rating?

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[Sam D]

I just checked today. My Javron struts are definitely different sizes.

[TurboBeaver]

Then I stand corrected on that as I must have misheard what Jay told me that day on the phone! He was explaining to me why his are heaver; and he must have ment the wall thickness was "thicker" than Airframes rear strut. And I misunderstood him to say the " profile" was the same as the front struts so I assumed he ment just that. So much for that communication
Mine are still enroute with a new fuselage
for Maine so I don't have them yet. But certainly looking forward to replacing the old small fork ones that are probably 50 plus years old! So my bad on that discribtion........ And thanks for clarifying that!

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[reliableflyer]

Some people used to put front struts on the rear to prevent the struts from folding when the aircraft was tied down tail into the wind in strong wind conditions. To do that the forward inboard portion of the rear strut had to be modified to make room around the rear of the front strut.

[skywagon8a]

Some people used to put front struts on the rear to prevent the struts from folding when the aircraft was tied down tail into the wind in strong wind conditions. To do that the forward inboard portion of the rear strut had to be modified to make room around the rear of the front strut.

The end which attaches to the wing would need a major alteration in order to line up with the wing fitting. This since the front strut angles back to the fuselage and the rear strut angles forward.

[Dan Gervae]

So...update: I’m having some end fittings made for a set of aluminum struts which I will assemble when the components arrive...Southern Aero is going to help me out there. He’s a one man show and picks up projects to do here and there...he’s working on his own experimental Stretched Pacer...which sounds very cool. I pinned the wings on with the unsealed Supercub struts I have laying around and got an empty weight...so here’s what I have to date.
PA11, Stewart’s fabric system, 2-18 gallon tanks, Extended baggage w/external access door, 26” ABW, TK1 Shocks, Catto 76-36 prop, O-200A w/ B&C starter and 8a pad genrator(dynamo), 6 qts oil in the sump, folding/sliding front seat/aluminum pan rear seat, Earth x 680c battery...no interior except extended baggage is carpeted and boot cowl insulated. As is stands I’m at 875 lbs....I had hoped for 850, but I kept adding junk I didn’t need (heavy front seat, heavy Galvanized firewall...shall I go on....). I know I should shed 10 lbs with the aluminum struts, but in reality I’ll be close to 900 lbs...bring a realist because things tend to go that way. I’d say the best I can do is 880. Otherwise I start tossing things, starter (7 lbs?) right tank, 13 lbs w the lid....lol. And so on . Guess I’ll have to see how she flys first. Now, my metal for inside the hangar is coming next week and I can install that and blow in insulation....put the heater in Tuesday night. Progress!

I didn’t have the windows installed, but I piled them inside the cockpit with everything else that goes in there when I weighed it...I weighed my ailerons and wing tanks w/all components and added it to the score. I even left some wrenches and a hammer on the floor trying to keep it as real as I can. This was preliminary so I can make some final decisions as I assemble things permanently for the inspector.

I will permanently mount my hangar heater after the interior is finished...but I want to have it running while I finish insulating walls and put ceiling up. Lol
I guess at the end of the day with all that extra crap even if I hit 900 it won’t be horrible. I just had that 850 number seared in my brain��

[Dan Gervae]

[Crash, Jr.]

Not too bad on weight. Realistically most PA-11's come in around 875-900lbs all up. PA18-95's around 950. Pretty decent weight when you count all the things added plus the big tires.

J3 gang can get down to the low 700's but you're missing a lot of airplane parts at that weight. Feels less like flying in an airplane and more like a 85hp kite.

[Dan Gervae]

Not too bad on weight. Realistically most PA-11's come in around 875-900lbs all up. PA18-95's around 950. Pretty decent weight when you count all the things added plus the big tires.

J3 gang can get down to the low 700's but you're missing a lot of airplane parts at that weight. Feels less like flying in an airplane and more like a 85hp kite.

Ha, yup My C90 T Craft is 780lbs no interior, no electrics. (it's 909 on floats) Thanks for the encouregment....Sometimes when I see the planes some of the talented builders on sc.org put together, I feel like a hack. lol. I try for excellence, but sometimes fall short...I have gotten so much good info from this site it's incredible. I try to offer my humble pitance when I can ,but this is a place where most of the data is coming my way, not the other way around.

[jrussl]

That is going to be one sweet plane, Dan! Congrats on getting it near the finish line.


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[Douten]

Now you have me worried my 11 is 904# on 25x11x4 wheels, c90-8, 1 18 gallon tank, extended wings, folding seat,supercub trim and elevator control, bolt on float fittings, metal covered with Naugahyde interior, and was hoping the new one would be low 800#, 2 18 gallon wing tanks, c90-8, extended wings, Kydex interior, super cub trim and elevator controls, welded float fittings, metal back to wing attach fittings and belly under cockpit, 800-4 or 25x11x4 tires. folding seat or adjustable folding (I have both). Any idea what your wings weighed with tanks?

[Dan Gervae]

Now you have me worried my 11 is 904# on 25x11x4 wheels, c90-8, 1 18 gallon tank, extended wings, folding seat,supercub trim and elevator control, bolt on float fittings, metal covered with Naugahyde interior, and was hoping the new one would be low 800#, 2 18 gallon wing tanks, c90-8, extended wings, Kydex interior, super cub trim and elevator controls, welded float fittings, metal back to wing attach fittings and belly under cockpit, 800-4 or 25x11x4 tires. folding seat or adjustable folding (I have both). Any idea what your wings weighed with tanks?

No Douten, I should have weighed them seperately....I can only tell you that they are normal sized J3/PA-11 wings but have mostly wood ribs with metal spars....Left wing has the standard Piper landing light set up. If I end up taking them off again, I will try weighing them seperatly....I think you could easily do 830-850 lbs (maybe less)? with a 90-8 and no electrics.....I feel like there are a few things I consider heavy on my plane, such as the front seat frame which folds and slides is 10.5lbs.....the back seat pan is fairly stout, but the weight escapes me at the moment (I will check my builders log)....I have a heavy galvenized firewall with a single wrap boot cowl, I have plywood floors and plywood extended baggage....things I consider light are Catto Prop (9lbs), Earth X battery (3.9lbs), I think you will save at least 23-27lbs over me by just not having an electric system...(thats what my Starter, Alt,Battery, Solenoids, Cables, switches weigh) and your 90-8 is 6 lbs lighter than mine is without accesories according to the TC. I have welded float fittings and PA 22/20 balanced elevators w/trim tab controlled by Ray Allen servo via a fairly heavy control rod that runs from the baggage area back to the tab.....so I would say you are on track in my opinion.

[cubdriver2]

Now you have me worried my 11 is 904# on 25x11x4 wheels, c90-8, 1 18 gallon tank, extended wings, folding seat,supercub trim and elevator control, bolt on float fittings, metal covered with Naugahyde interior, and was hoping the new one would be low 800#, 2 18 gallon wing tanks, c90-8, extended wings, Kydex interior, super cub trim and elevator controls, welded float fittings, metal back to wing attach fittings and belly under cockpit, 800-4 or 25x11x4 tires. folding seat or adjustable folding (I have both). Any idea what your wings weighed with tanks?

Did you count the cooler weight?

Glenn

[Dan Gervae]

Now you have me worried my 11 is 904# on 25x11x4 wheels, c90-8, 1 18 gallon tank, extended wings, folding seat,supercub trim and elevator control, bolt on float fittings, metal covered with Naugahyde interior, and was hoping the new one would be low 800#, 2 18 gallon wing tanks, c90-8, extended wings, Kydex interior, super cub trim and elevator controls, welded float fittings, metal back to wing attach fittings and belly under cockpit, 800-4 or 25x11x4 tires. folding seat or adjustable folding (I have both). Any idea what your wings weighed with tanks?

BTW, I didn't know you were building a new Cub.....Is it a plans build? or did you get a kit? Details Or are you doing a rebuild?

[Douten]

It's experimental built as close to my 11 as I can only lighter where I can. I have one wing that I hope to have ready for cover by the end of next week my metal for the leading edges should be in today went with .025 instead of .020 or .016 looks like 3 1/2 pounds +/- over .016 per wing but will be stronger. I built new brackets for my Amphib so I can put them on either plane. Going to make a seeder hopper that will mount where the back seat is so this plane won't be full of acorns that don't make it out the window . Glenn I have a removable cross tube that can be turned upside down so I can fit a bigger cooler in there just need to make a shelf over the stick stub.

[dgapilot]

Loose that alternator! I agree, not much weight, but it forever makes it so transponder and ADSB are required in rule airspace. If it never had the alternator, you are exempt from transponder and ADSB under Class B and Class C.


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[skywagon8a]

Loose that alternator! I agree, not much weight, but it forever makes it so transponder and ADSB are required in rule airspace. If it never had the alternator, you are exempt from transponder and ADSB under Class B and Class C.

If you still feel the need to generate electricity, use a wind driven source. You are still exempt from the transponder and ADSB requirements since the source is not engine driven. Engine driven is the clue.

Try something like this. It is a dynamo from a Kubota tractor which puts out 15 amps. Works great.

[Dan Gervae]

I actually have one of the BPE 14 Turbo wind generators sitting on my workbench....I helped a buddy pick up a project and it was in the pile....I offered to buy it from him...he gave it to me....wouldnt take money since I helped him out.....good buddy. I told him they are almost $1000 new.....he didn't care..... good buddy like I said. I suppose it is something to consider.....I had considered buying the AV30 by Uavionics and tying in the tail beacon for ADS B out.....I was thinking they will eventually require it somehow or another.....who really knows

[skywagon8a]

I actually have one of the BPE 14 Turbo wind generators sitting on my workbench....I helped a buddy pick up a project and it was in the pile....I offered to buy it from him...he gave it to me....wouldnt take money since I helped him out.....good buddy. I told him they are almost $1000 new.....he didn't care..... good buddy like I said. I suppose it is something to consider.....I had considered buying the AV30 by Uavionics and tying in the tail beacon for ADS B out.....I was thinking they will eventually require it somehow or another.....who really knows

As long as you are aware the airplane must never have been certificated With an engine driven electrical generator !!! Once done you can/may not go back. You can not chose in the future to remove the engine driven generator in order to achieve the exception.

[Dan Gervae]

Technically I could get the airplane certificated with no charging system installed at all I suppose....I could charge the battery as needed, but maybe the wind generator can be a start....I would have to blank off my vacuum pump pad on the front of my motor...anyone have oil leak issues when doing that? Also, I have several ideas about where to mount my Earth X 680c and the master and start solenoids, but wouldn't mind seeing how others have done it.....Ever seen an earth x mounted at 90 degrees on the engine side of the firewall? or on the cabin side? this gets it up out of the way some while making removal easier. I'm interested in thoughts on this. It could go between my feet as well with some bracket work.....those small tubes come together there.....another option is under the front seat....I really want to make the cables as short as possible, but I have seen some guys do the under seat STC on certified stuff. Also, I would need to understand if I need the crowbar overvoltage set up with the BPE using the Earth X
https://johnpropst.yolasite.com/reso...or%20rev10.pdf
I found this nice article

[Cub junkie]

I would initially get the airworthiness certificate without an engine driven alternator as suggested. Then you have flexibility. For me the less government involvement the better, especially with this new government we just got. Batteries have had leaps in technology the past few years.

[Dan Gervae]

Here’s where the battery is going ....adel clamps on bottom mounts...aluminum angle attached w/adel clamps to hold the top across the vee and solenoids on the engine side of the firewall. I can’t think of a better spot. To tight in the engine side and it will get hot.

[skywagon8a]

Technically I could get the airplane certificated with no charging system installed at all I suppose....I could charge the battery as needed, but maybe the wind generator can be a start....I would have to blank off my vacuum pump pad on the front of my motor...anyone have oil leak issues when doing that? Also, I have several ideas about where to mount my Earth X 680c and the master and start solenoids, but wouldn't mind seeing how others have done it....

This is what I did. I live under a class B umbrella where transponders and ADS-B out are required. So....... I am exempt. Recharged the battery every once in a while. One day I was flying out over the ocean when I ran my battery out of juice. My P-mags kept themselves running. BUT, I hightailed it back home thinking that was a dumb thing to do. Thus the wind driven dynamo with more juice than I will ever need. Now no worries. Can't even tell it's out there.

Pull the vacuum pump drive off the accessory case, install a metal plate and gasket over the opening....done. There are plates made for this or just use a square of 1/4" aluminum plate with four holes.

[skywagon8a]

Here’s where the battery is going ....adel clamps on bottom mounts...aluminum angle attached w/adel clamps to hold the top across the vee and solenoids on the engine side of the firewall. I can’t think of a better spot. To tight in the engine side and it will get hot.

Are you going to install cabin heat?

[Dan Gervae]

Are you going to install cabin heat?

Yes, I made the box and it mounts right below the battery there on the engine side obviously.....are you thinking the battery will get too warm from that? I could offset the box to the right a little?

[skywagon8a]

Yes, I made the box and it mounts right below the battery there on the engine side obviously.....are you thinking the battery will get too warm from that? I could offset the box to the right a little?

I just don't see the opening in the firewall. It must be hidden close to the battery? If so, I would make a deflector just for safety's sake to keep the heat away from the battery.

[Dan Gervae]

I just don't see the opening in the firewall. It must be hidden close to the battery? If so, I would make a deflector just for safety's sake to keep the heat away from the battery.

The hole is not cut yet I hadn't decided where to put it since I was still fussing over where to put my battery Until today

[dgapilot]

On my Clipper, I’m putting the EarthX on the front side of the firewall. Got rid of the Piper exhaust and I’m putting a Sutton exhaust, but that isn’t an option for a Continental engine. You could go with Aeronca style exhaust to get rid of the muffler by the firewall.

If you’ve ever seen a lithium battery cook off, you wouldn’t want it in the cabin! I know they’v come a long way, but for me, other side of the firewall and the built in monitor system is the only way I’m comfortable.


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[Dan Gervae]

here is the only option on the engine side...it’s probably not a bad spot...lots of airflow in that spot...I could also rotate it 90 degrees to allow easier access and easier removal.

[wireweinie]

Have you considered mounting it between the kick panel and boot cowl? Left or right side. I wouldn't want it mounted right over the cabin heat valve as in the pic you showed.

Web

[tempdoug]

pretty cool(in more ways than one)

[tempdoug]

https://dakotacub.wordpress.com/2010...l-battery-box/

[DENNY]

Dan
The scat hose off the cabin heat can get well over 200 degrees. Local guys ran one to the rear under the pilots seat. They had a bag of shells on the floor while wolf hunting. When they got back they found several of the shells plastic melted from the heat. You might get by with some insulation but now it will be hard to divert for defrost. DENNY

[skywagon8a]

This is what EarthX has to say.
https://earthxbatteries.com/engine-c...-installations

[dgapilot]

This is what EarthX has to say.
https://earthxbatteries.com/engine-c...-installations

That’s one reason I went with the Sutton exhaust, move the heat away from the firewall where my EarthX battery will be installed.


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[skywagon8a]

If you’ve ever seen a lithium battery cook off, you wouldn’t want it in the cabin! I know they’v come a long way, but for me, other side of the firewall and the built in monitor system is the only way I’m comfortable.

dga,
Which version of the lithium battery are you referring to? The EarthX claims this: "The EarthX batteries use cells made of Lithium Iron Phosphate (LiFePO4) chemistry that was developed in the U.S.A. This chemistry is the highest performance, most robust and the safest on the market today."
https://earthxbatteries.com/our-batteries/lithium-battery-technology
Based upon EarthX's claims, it appears they are as safe as a lead acid battery. Using their claims, it appears they are safe for cockpit installation. If so, I would think it would be a better environment for the battery to be behind the firewall rather than with the engine?

[dgapilot]

Mine will be the EarthX EXT 900-TSO. I agree the iron phosphate is better that lithium ion, but it’s still new technology. My airplane is certified, not Experimental, so I have less latitude. Had to work up a Field Approval that my FAA Inspector would buy off on (they don’t let me use my DAR or DER on my own airplane).


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[hotrod180]

..... (they don’t let me use my DAR or DER on my own airplane).

That seems like a bullshit policy to me.
IMHO no different than an IA signing off his own airplane's annual.