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Interested in building an experimental PA-18

FKreider

Registered User
Hello I hope this is a good place to post my questions regarding scratch building an experimental PA-18.

I will say that I have absolutely no experience building a plane, at this point this is all hypothetical, just trying to get a good idea of what will be required when I start this process. Please excuse how inexperienced I am, I have A LOT to learn.

I have done a considerable amount of research (via the internet) about scratchbuilding an airplane, and again and again I keep coming back to the Piper SuperCub.

I like the way Wag-Aero's Sport Trainer wings are built, they apear to be within my ability to build fairly easily, because of this I am considering using their plans.

However I am wondering how different the Sport Trainer's fuselage is from the original PA-18. I see that in order to fit a 150hp engine to the sport trainer you must build the "Super Sport Trainer" version of their plans, where there are two extra pieces of tubing that obstruct front view, I have not seen this in person but I do not like the idea of it.

I’m wondering if it would be possible to build a LSA PA-18 "clone"using the Wag-Aero plans and the Northland CD with the original PA-18 plans; using the original fuselage and the Wag-Aero wings.

Or would I be better off sticking to one or the other? I am also interested in having flaps, which the Wag-Aero plans do not provide.

I am not worried about welding or fabricating the fuselage, I have a friend who has built roll cages with Nascar spec. tubing, so notching and fitting the tubes does not worry me, also my brother is a welder by trade, so the fuse will be all TIG welded.

The parts that concern me are keeping it light for LSA and the power plant choice. I want to have extended gear with tundra tires for off airport landings, STOL capabilities are important to me. I would also like to eventually get the plane on floats so I realize that extra HP does not hurt for this type of flying.

Hope I haven’t rambled too much and some of you guys have some insight to the questions I have.
 
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The Wag Aero Cub is much closer to a J-3 than a PA-18. It can be built to light sport standards, but not with a 150 hp engine. The empty weight will just be too heavy with the bigger engine and other changes you need to handle it. Your maximum engine size realistically will be the Lycoming O-233-LSA with the older O-235 possible, but a bit on the heavy side. The Continental O-200 is another option as are various modified versions of some smaller Continental engines. If you are trying to meet LSA requirements it is a real battle to keep empty weight under control, so engine choice becomes a big concern.

Legend has a new model, the Super Legend, that is probably available in kit form. It is sort of a cross between a J-3 and a PA-18 but roomier than both. It has flaps, wider fuselage and other refinements. Unfortunately it will be somewhere over $80K to complete. (I haven't checked prices lately)

You can also find plans and pre-made components to build your own PA-18, but you will not be able to fly it under LSA rules because it will be too heavy. If you can fly as a private pilot you will open up that whole host of possibilities that building a PA-18 type plane will make available to you. You just need to decide which way you want to go.

The Wag Aero is a good way to go if you are on a tight budget and want to do everything yourself. Its main drawback is that it is pretty tight inside for a big guy. The lack of flaps is really not such a bad thing for that airplane. Just learn how to slip.
 
Well that is some great info, as of right now LSA is the only option.

I would also like to build as much myself if possible. I like to fabricate/build and it will allow me to build as I can afford to; time wise as well as money wise.

Sounds like I should just stick to the Wag Aero plans and build time for my private license.

I'm 5' 10" at 150lbs so I don't think the Wag Aero will be too tight of a fit
 
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A light sport super cub with a O-320 is possible if you go bare bones, no frills. Maybe Coyote Ugly will chime in here, his plane is a light sport 160 hp I believe.
 
Hello I hope this is a good place to post my questions regarding scratch building an experimental PA-18.

I will say that I have absolutely no experience building a plane, at this point this is all hypothetical, just trying to get a good idea of what will be required when I start this process. Please excuse how inexperienced I am, I have A LOT to learn.

I have done a considerable amount of research (via the internet) about scratchbuilding an airplane, and again and again I keep coming back to the Piper SuperCub.

I like the way Wag-Aero's Sport Trainer wings are built, they apear to be within my ability to build fairly easily, because of this I am considering using their plans.

However I am wondering how different the Sport Trainer's fuselage is from the original PA-18. I see that in order to fit a 150hp engine to the sport trainer you must build the "Super Sport Trainer" version of their plans, where there are two extra pieces of tubing that obstruct front view, I have not seen this in person but I do not like the idea of it.

I’m wondering if it would be possible to build a LSA PA-18 "clone"using the Wag-Aero plans and the Northland CD with the original PA-18 plans; using the original fuselage and the Wag-Aero wings.

Or would I be better off sticking to one or the other? I am also interested in having flaps, which the Wag-Aero plans do not provide.

I am not worried about welding or fabricating the fuselage, I have a friend who has built roll cages with Nascar spec. tubing, so notching and fitting the tubes does not worry me, also my brother is a welder by trade, so the fuse will be all TIG welded.

The parts that concern me are keeping it light for LSA and the power plant choice. I want to have extended gear with tundra tires for off airport landings, STOL capabilities are important to me. I would also like to eventually get the plane on floats so I realize that extra HP does not hurt for this type of flying.

Hope I haven’t rambled too much and some of you guys have some insight to the questions I have.

With the potential to have a drivers license medical in the future I would not base a new build on LSA standards.

Tim
 
buy a cheap j3 w/ 85 or 90hp to fly now and start scratch building. Get your private in the J3 - when you get the experimental pa18 ready to hang the engine and prop - sell the j3 to complete. Scratch building is going to take you a loooong time if this is your first one.

Have you considered a rans ?

Backcountry supercubs is working on an lsa cub variant.

http://www.supercub.com/
 
soyAnarchisto has some good advice. It will take a first-time builder quite a while to scratch build a Wag Aero. That doesn't mean your shouldn't do it, but if you are building to get something to fly and not for the experience of building there are a lot of easier ways to get something to fly. If your ultimate goal is to earn your PP and fly a PA-18 it doesn't make too much sense to invest that much time in building the Wag Aero first. It is simply not, on its best day, a substitute for a PA-18.

If you are still focused on light sport, the RANS S-7S is worth a look. You will need about $50K to build one with a used engine and modest radios, but you can actually put one together in 1-2 years of spare time if you really get to it. It is much easier to build than the Wag Aero because it is a kit, and it also comes with excellent plans and instructions, which the Wag Aero does not. Wag Aero plans are what you might call minimal.

Just something to think about.
 
I think others have said it well. Personally, I'd focus on getting the private license first. Unless money is no object, The homebuilt will suck a lot of your $capital while building, leaving little $ for lessons.

The Wag Aero Cub is just a J-3 with bigger engine, but not a Super Cub. I have seen some nice mods to make it more like a Super Cub, ie wing attach and skylight, flaps, seating, etc. If you are set on building a wood wing, then see Marty Feehan's project. You could put that on a Super Cub fuselage. There are lots of variations, but if you really want to scratch build a Super Cub, why mess around with Wag Aero? Get the Northland CD and go over to my web site to see what is involved.

I also agree with Tim, LSA might be moot soon. I wouldn't limit myself to those constraints. In the meantime you can start building rudder and brake pedals right now, using the drawings on my web site. Small enough to deal with until you get that private ticket!
 
I agree with Bugs about Wag Aero. The Cubby isn't a Super Cub. The wood wing I am building started from Wag's 2+2 Sportsman drawings with a bunch of changes. Specifically the addition of flaps, stock wood wing tip bow, and modification of the fuel tank bay (matches Bugs wing but in wood) make it a wood Super Cub wing. If you want to build a Super Cub with wood wings I would recommend you use the Wag Aero 2+2 drawings for the wing along with the drawing I have showing the modifications to Super Cub style and use the Northland CD to build a stock Super Cub fuselage. Wood wings are a lot less expensive to build and you can start building ribs for next to nothing $$$ wise while you finish your PPL. Lots of ways to go as you are likely finding out.

Marty57
 
If flying is in your blood, the sooner the better, soyAnarchisto makes an excellent point, I put over 900hr in two years on my cub instead of build or being a great cub. I can't wipe that grin off!!
Marty makes a great point, you can build a cub wing out of wood (Wag 2+2) and save $$$$ and with the NorthLand CD and Bugs site, you are basically home free to finish your 18 scratch build.
 
Wood wings are a lot less expensive to build and you can start building ribs for next to nothing $$$ wise while you finish your PPL.

^ This is exactly why I liked the Wag Aero plans, I figured I could start building the wing ribs with minimal investment to start out.

Being a student pilot and only 23 years old, Ive got nothing but time, I am up to a long term project. I might not have a place to build the fuse untill next year or so (2015)

Like I said before, I have a friend who is very good with metal, and my father has been a cabinet maker all of his life, I think he is interested enough and will help me with the wings!

Marty how close are the 2 + 2 wings to the original super cub wings? Besides the flap-modification, that is.
 
My 2+2 wings are pretty close to a Super Cub wing. Dimensions are all the same. The compression struts from spar to spar are same design as a wood spar J3, J4, and J5. The dimensions of the ailerons are exactly the same as the Super Cub with hangers designed for the wood spar Cubs. I did make my flaps and ailerons out of wood. I did change the spacing of the hinges for the flaps so the didn't have to drill through the wing attach fitting to mount the flap hanger. Distance between the spars is the same, stock wood wing tip bow. I know of at least one Super Cub from this site that used 2+2 wings on a Super Cub fuselage. Basicly a wood clone of a Super Cub wing. Take a look at my web site; all my construction since day one are shown.

Marty57
 
If your set on scratch building you might consider one of the Barrows bearhawk designs. They are all engineered to be scrach built AND kit manufactured sub assemblies are readily available. My goal was an inexpesive aircraft with cub-like performance and capability for remote Alaska. I started out scrach building and the my sistuation changed so I purchased a wing kit to finish. From plans to flying was 20 months as a first time builder. This was NOT a part time hobby project (I have 2-300 hours and lots of $$ invested). From my experience, the performance numbers advirtised on their website are realistic. I'm thrilled with my decision.
 
bpratt,
Same can be said about scratch building a Super Cub or 2+2 as the Bearhawk but better in my opinion. Any parts of the Super Cub or 2+2 that you don't want to build are available from a long list of suppliers. Can the Bearhawk be built with a wood wing if desired? I don't know how many manufacturers are making Bearhawk assemblies but I suspect there are more building Cub parts. As far as engineering goes I think that anything going into a Super Cub or 2+2 has been engineered and tested and flown for 60+ years. The Bearhawk is a great design but with a Cub type aircraft you can build and fly with anything from a 65hp on up and set the plane up to meet any mission you desire.

Marty57
 
You bring up excellent considerations, Marty57. I guess I just wanted to share a positive experience with someone considering a similar build. As a matter of fact, I've considered a project that combines a Bearhawk fuselage with D and E supercub style wings (with a Riblett airfoil). Thank goodness for the experimental category!
 
You won't know what to build until you have some flight time and figure what you really want. Bang for the buck a Pacer is a great trainer and will teach you a lot. Go find a hanger with old IA's that do fabric work and complete rebuilds. Bring beer and figure out what is good and what is for show. Don't start on a project until you know what you want down to the prop, tire, gage, and paint. Any change will cost money so have a good plan before you start. If I was your age and liked to fly I would find a way to do it for a living!! There is a going to be a huge need for pilots in the next 10 -20 years and you are in the door. If you REALLY LIKE TO FLY take the step and make it a job. Get your IA while you are at it.

Wow, poor guy just asked about building experimental and gets he's life planed:)
DENNY
 
Ok guys, after much thought and consideration, I believe I have decided on building a full fledged PA-18 clone using the Northland CD plans. I would like to go with Marty’s suggestion of using modified Wag-Aero 2+2 wings. I have decided that if I’m going to build a plane I’m going to build the one I really want.

So a couple questions:

I have been talking with my fabrication friend about the construction of the fuselage, and after showing him some pictures of other builders jigs and build process, he was convinced that we can build the fuse easy enough.

He has a CNC plasma table and we are hoping to draw up and cut out all of the flat stock brackets needed for the build.

He called his steel distributor today to get a basic idea of the cost for the 4130 steel tubing required; he was shocked at the price the distributor gave him.

We were looking at the “10562” blueprint page and he saw that a lot of the material was 1025 steel, his thoughts were that this would be considerably cheaper than the chromoly 4130. He asked me why not use this tubing if it was used in the original plane. So I was hoping you guys could answer this question for me.

The other question was regarding the specific type of tubing used, I told him 4130 DOM tubing, when he asked for a quote the distributor listed four different types of tubing that matched what he asked for, I believe the difference was DOM vs. HREW. I told him I thought it needed to be DOM, I hope I was correct.
 
For building one fuselage it's cheaper to buy tubing from an aircraft supplier than go through a steel distributor, even if you are a big shop. Most distributor's want to sell a mill run or large amount. Piper used very little 4130 in their '40's era tube fuselages, just critical attach points. In the '50's they started using all 4130. Much of the mild steel you see spec'd out is because they(Piper) were cheap and they used a lot of brackets for several different airplanes. Mild steel is also easier to form and easier on tooling. Cub fuselages are not that difficult to build but unless you are going to build more than one it's cheaper to buy the wing and landing gear attach brackets from one of the many suppliers. Bending those gear fittings accurately is challenging and takes time and will always produce scrap material while you learn the bend allowance and radius. Plenty of homebuilt cub clones/projects to view on this site. Use other's experience to minimize wrong moves. Just my 2 cents.
 
When I started my 2 +2 I priced the different ways get materials for the fuselage. I wound up buying Wags fuselage material kit. First, they figured out all the quantities, second they supplied those above mentioned critical fittings at a price I could not beat. You still have to fabricate plenty with the flat stock provided. If you bought the Wag Cubby fuselage materials kit along with the 2+2 wing attach fittings ( same as super Cub), Wags Cubby plans and the Northland Super Cub drawings you would be in good shape to build a Super Cub exp. Use the wing drawings I have drawn to modify the Cubby wing and you are good to go. This is the lowest cost to build but the longest time frame. I'm past 2200 hours and will be close to 3000 or more when finished.
Marty57
 
Like said, get your steel from aircraft suppliers. For small quantities, check if you have a walk-in metals store in your area. We have one and although their prices are a little higher than Wicks or ACS, very handy for small batches.

I would start small if I were you. See if you are really into it. Have you built any flying model airplanes in the past (from plans or kit, not ARF)? Some people are not destined to build. See if you can accomplish the rudder and brake pedals. Then try the stick torque tubes, or build the vertical fin. JMHO because a project like this takes an enormous amount of dedication. Not saying you don't have it, but good to check yourself.
 
Bugs, your advice is pretty good, I think starting with the rudder and pedals might be a great way to get building for cheap.

As far as the actuall build process and dedication goes, I'm not worried about that. I rebuilt a Jeep over a couple years from the ground up. The only things left that are factory are the frame, basic body and dash, everything else has been replaced and customized. Modifications include; Mercedes diesel engine, Dana 44 axles with 4.88 gears (which I set up myself), transfercase with aftermarket 4:1 gear ratio, locking differentials, cage, ect ect.


I greatly enjoy the build process, the only part I hate is waiting for parts to show up!
 
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I have a friend that started out my welding the rudder pedals. He did not get good penetration, the rudder pedal failed on takeoff and it resulted in a very ugly ground loop. You might find something other than a primary flight control to start your welding practice on.

just my opinion

Bill
 
I have a friend that started out my welding the rudder pedals. He did not get good penetration, the rudder pedal failed on takeoff and it resulted in a very ugly ground loop. You might find something other than a primary flight control to start your welding practice on.

just my opinion

Bill


Bill, my assumption is you already practiced making wind chimes and are confident in you welding ability. With this prerequisite, what else is there to start with? Any specific item that is welded could be up for grabs for an accident.
 
I have a friend that started out my welding the rudder pedals. He did not get good penetration, the rudder pedal failed on takeoff and it resulted in a very ugly ground loop. You might find something other than a primary flight control to start your welding practice on.

just my opinion

Bill

Bill, that is an interesting story, a great example of how importaint any mechanical part can be.

I am by no means an expert but I am not just learning to weld, I bought my first MIG with the money from my first job, before I could even get a drivers license. My brother and my friend will most likely be doing a lot of the welding on the fuse, since they both do it every day for a living, they are far better than I and I trust their welds more than the ones that you find on most new vehicles.
 
There's a lot of discussion about Mig vs Tig welding 4130 . Mig is not advisable, sorry to say, for 4130. You will need to use Tig or gas weld. Do a search "mig vs Tig aircraft welding" and you can read the discussions.
Marty57
 
Marty, I was just using that as an example of how long I've been welding, not a first-timer here. The fuse will be all tig welded.

Can .035 tube be used in place for some of the .028? Im thinking it will cause a significant increase in weight.
 
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In regards to your question about using .035 in place of .028. That's done often. .028 wall anything is of course lighter but also about twice as much a foot as .035. Piper was the king of lightweight. They use a lot of thin bent up channels for many things. Using .035 in place of .028 is not a deal breaker. It saves money.
 
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