Wide-body Sportsman 2+2 build

[tcbetka]

Hello all,

I've had a set of plans for a Wag Aero 2+2 project since the mid-90s, and even built a narrowed version of the fuselage back then, along with the tail feathers and gear legs. Life got in the way though when I finished Med School and had to go off to do further training. I ran out of time and a shop to continue the project, and in a moment of weakness...I sold it. That's always bothered me. A couple of years ago I bought an updated set of the plans (well, they are 2 years newer than the first version I bought), so now I'd like to try this again. I retired from practicing medicine about 10 years ago, and work from home doing software development--and also do some aircraft restoration/recovery work to help out an A&P friend.

The first version of the fuselage I built was more of a fattened pa-12, narrowed from the WA plans by 5-6" or so. This was back in the day that my wife didn't mind sitting in the back seat. Times have changed, and she thinks a 4-place configuration would better suit us. She's probably right, so that's what I'm planning to build. But I think the stock 39.5" maximum width will make things a bit too narrow, even with staggered (sliding) seats, so I'd like to widen the fuselage a bit. But the question is: How much is enough without having to re-engineer the whole thing?

I've spent a couple of weeks now perusing through every pa-14/2+2 thread I can find in the forum here, and have seen several references to people saying that the 2+2 is pretty narrow. I've seen mention of two 2+2 aircraft that have been wider than the plans: One was apparently 45" wide, and one was 1" wider. I was thinking that 2-3" would be about the least I'd want to go, which would put the width on-par with the earlier C-182 airframes which seem to be in the 42" range. The C-172 aircraft tend to be around 40" wide--at least the older ones do, which is what I've spent the most time in as a CFI. So a 3" increase to the 2+2 would give me 42.5" at the widest part, right at the forward door post.

As I mentioned, one thing I really DON'T want to do, is to re-engineer the aircraft. I plan to model all of this in Solidworks before starting the build, but I plan to keep the build pretty stock per the plans, except for adding the jack-screw for the horizontal stabilizers, and perhaps slightly longer gear. I plan to use Supercub-style (which are basically per the plans), as well as pa-12 wings (with flaps). But nothing fancy though, like slats or PStol flaps. This aircraft will pretty much be used for pleasure, not back-country bush flying. We don't do much of that here in Wisconsin, so I figure a modestly widened 4-place cruiser will be plenty for what we need. Power will either be a 160hp 0-320 or an 0-360. We'll cross that bridge when we get a better idea of what the weight will be (which Solidworks will help with, to some degree). But I'm not planning to lengthen the fuselage any, or even increase the size of the tail feathers. I certainly don't plan to be screwing around with the CG envelope at all.

So I would appreciate any input you pa-14/2+2 guys might be able to offer in terms of how wide is too wide? If you had to do it all again (2+2 guys), how wide would you make it this time? I've read about people fabricating bubbled-out side windows to increase shoulder room, but that still leaves the seats in the same place, and I think I would like to have them 1-2" farther apart at least. My plan is two sticks in this thing, with the power controls between them.

Thanks much for any input you guys can offer.

TB

EDIT: I forgot to mention that I have the Northland Cub drawings, as well as all the short-wing Piper drawings as well. So in effect I could easily swap out the SC tail feathers for those called out in the plan. I'll need to compare the two sets to see what sort of difference(s) there might be in surface area(s), but seeing how you have to build a set from the plans either way...it wouldn't really make much difference which plans you used, I guess.

 

[JTA]

tcbetka, I'll chime in here as I owned and flew a PA-14 for 6 years. Awesome plane, loved it. My question would be are you sure you want to make it wider? I'm 190 and routinely flew with friends some well over 200 with no issues, yea its snug but was never an issue maybe because we were usually on a mission of sorts (hunting/going to the cabin etc). Also mine was a 1948 that did not have sliding seats. I think the later models had one seat sliding. I would even argue that having it the stock width allowed me (with clear seaplane doors both sides) to easily see both tires/landing gear from the left seat, which was nice. It had very good visibility. I wonder how much more time it would take to make it wider? Maybe not a big deal? I have no experience building frames so can't help there. Definitely yes on the jack screw, I would build it as close to Piper as you can. My -14 had a O-360, great for take off, I could match super cubs for takeoff. Landing not so much. I always felt it was nose heavy and though not sure I wonder if it would have been better with an O-320. I sold the -14 to fund the restoration of a -18. The -18 is a better fit for the kind of flying I do. I wish I could have keep the -14 though, was great for packing the kids in and going fishing. Before I had the -14, I owned a PA22/20, floats, skis did good to, but I would not take it into short strips, are you stuck on long wing piper? Pacers are a good buy. You obviously have experience building so I don't need to warn you about the time and energy involved in a build. I spent two years and over 2000 hours restoring my supercub. I spent every spare second I had into building it and enjoyed the build, but it killed me to not be flying for those two years. Although it made financial sense, if I could go back in time I would have figured out a way to keep the -14. Oh, by the way, I'm in the process of restoring another supercub, must be a sickness. Good luck with the build!

 

[tcbetka]

Hello JTA, and thanks for the reply in this thread!

You raise some great points, but I do think it would be best to widen the airframe. I've never sat in a pa-14, and (in fact) may not have ever even seen one in person. But I have seen a couple of 2+2 aircraft up close (at EAA, here in Wisconsin), and I've spent quite a bit of time giving guys dual and doing flight reviews in pa-22 aircraft over the years. Not sure of the years of those Tri-Pacers though, to be honest--but I'm certain that one had the large left-sided backdoor, so I'm thinking it was 1956 or newer. It was a tight fit, and he wasn't that big of a guy. I'm 6'4" and go 260-265, so having something less than 40-41" wide wouldn't be a comfortable ride for me, even with the sliding seat. I've spent 1000+ hours in various C-172 aircraft, and many of those were with larger guys as well. You definitely have to stagger the seats, and one person usually has to put their inside arm on the back of the other person's seat in order to "free up" some more room. Move to the C-182 and it gets significantly better: Not perfect, but much more comfortable. The research I've done shows that most 172's are in that 40-41" wide range, and most 182's are in that 42-43" range. I haven't measured many of them though, so there may be exceptions.

That said, yeah...I feel pretty strongly that this 2+2 cabin would need to be wider. I'm thinking of going out 1.5" on either side of center, to make it a 42.5" wide cabin. Make it 1.5" wider in the cabin section at the bottom-, top-longerons and the birdcage (to not screw up the wing strut lengths), and then start decreasing the extra width by 1/2" at each of the main "bulkhead" sections (confluence of tube cross-braces) as you go aft to the tail. By the time you get all the way back to the tail post, you are basically at the measurements of the original plans. Then the next station forward would be 1/2" wider (each side of center); the next one up 1" wider (in total) and then up to 1.5" wider on each side by the time you hit the back of the cabin. That's not the "REALLY WIDER!!!" plan some people have mentioned to me in other conversations, but it seems like a good compromise and doesn't require a convoluted engineering re-design to do. And you can still use Univair struts because you haven't messed with the relative position of the attach points in question, as I mentioned. I want to get it modeled in Solidworks though first, to confirm everything I've just stated. Solidworks IS my sanity check when it comes to this stuff anymore, so I'm not cutting the first tube until I'm happy with the design, which will take 1-2 months. But you don't want to get this stuff wrong, so if it takes 2 months...it takes 2 months.

As to the longer time required to build from scratch--tell me about it, lol! I've been there. That said though, the fuselage takes 150-200 hours to get welded up and to the point where all the tabs start going in. So I feel pretty confident that I can have it sitting on the gear within a year.

Regarding your pa-22/20 comment: Oddly enough, yesterday I was just offered a 1957 pa-22/20 project (Tri-Pacer converted back to a tail-dragger), complete with an O-320 engine & prop. It needs bottom longerons, but I would do the Super Tri-Pacer conversion anyway--which requires lengthening the fuselage. But there are problems with going this route, if your preference is to go EAB. Basically, it would be VERY hard to use that project for anything other than keeping it as a certificated airframe. All a person needs to do is go to the FAA's Amateur-Built Fabrication and Assembly Checklist and review the "tasks" they want to see accomplished. It's pretty easy to see that any previously certificated components, while theoretically possible to use, don't even get counted towards either amateur-builder assembled or amateur-builder fabricated, yet they still count towards the total number of tasks. So use too many certificated parts and before long you don't have enough other tasks remaining to get you over the 51% hump. Therefore the only feasible way to buy that project would be with the intention of keeping it certificated--which makes everything WAY more expensive. For instance, a 10.6" (ie; landscape) certified Garmin G3X is about $10600 MSRP right now, while the same unit for Experimental aircraft is just under $4000.

So I guess what I'm saying (in long-winded fashion, I'll admit) is that; 1) yeah, I'm pretty convinced that a wider 2+2 would be better, and 2) the only good way that I can see to mod up a pa-22/20 is to keep it certificated, which is something I'd rather avoid I think. I flew freight in AK for a year back in the 90s, and maybe if I lived closer to AK I would elect to stay in the certificated world--as it might turn into a commercial-type endeavor. However here in WI we don't do much bush flying, and having a nice comfortable (and widened) 2+2 Sportsman would be all the aircraft I'd ever need. Your O-320 idea sounds wonderful though, especially since it's not likely that I'll ever need to pack 4 people and gear in the thing. Me, the wife, and a couple of pooches would be about all we'd ever carry--so a 150hp or 160hp O-320 should be all we'd need, I would think. If I was to want the O-360 up front, I think I'd need to stretch the fuselage a bit to counter the extra weight up front. I can do that math of course, but I'm just not sure it has to be done for our use-case/mission for this aircraft. This is not going to be a working aircraft, for the most part. Hence 150/160 ponies might well be as much power as we ever need.

Thanks again for your reply.

TB

 

[CamTom12]

Have you thought about the Bearhawk line?

 

[tcbetka]

Yeah, I actually have plans for the Patrol. Nice aircraft--but the two-seater is something we're not interested in right now. I've sat in the 4-place, and it's too small for me. The 5-place is a LOT of aircraft, although admittedly you could just make it into a bit of a "stretched" 4-place I suppose, to get back some room. Not sure of its width though, as I haven't seen data on that.

Here's the problem(s) with the BH series of aircraft, as I see it:

1) Complicated wing construction for scratch builders
2) Single source of kits for buying what you don't want to build

I've talked to Mark Goldberg several times, and also to (designer) Bob Barrows. Great guys--no complaints there. However Mark's source for all the kits is in Mexico, and they can only do so much. Last I heard they were 18-24 months out on many things, but that was a few months ago. I'm not in that world though, and don't keep up with their status. They might be shorter now.

With the Piper-style builds, there are multiple sources for EAB stuff: Univair, Javron, Dakota Cub, Airframes Alaska, etc. A bunch of others too, I'll wager. So you build what you want to build, and then when you want to buy something to save time...there are often several options in terms of who to buy from. It's not so much of a "cost" thing as it is an "availability" thing.

So although I've looked at them quite a lot actually, I believe I've decided against the BH. Come to think of it...can I interest you in a "lightly-used" set of Patrol plans? ;-)

LOL!

Thanks for your post.

TB

 

[Paul Heinrich]

Bubble side windows aren’t an option if you want them to swing up.

 

[tcbetka]

Bubble side windows aren’t an option if you want them to swing up.

Excellent point actually, thank you. That would indeed cause an issue right at the end there, lol.

TB

 

[Paul Heinrich]

Also if you widen the fuselage you won’t be able to open a conventional style door, either, because it won’t clear the struts.

Come on; are you just teasing us? 6’4”, 265 lbs., wanting to fly side by side with your wife and with 2 dogs in the back?!?

I’m sorry, but a 160 hp 2x2 simply isn’t the airplane for you. Nor is a 12 or 18. IMHO, of course.

It doesn’t sound like you have to pinch pennies, so why don’t you just buy the nicest 180/185 you can afford and be done with the idea of building a marginally less cramped, underpowered rag wing?

 

[tcbetka]

Also if you widen the fuselage you won’t be able to open a conventional style door, either, because it won’t clear the struts.

Sure you will--because you're widening the entire cabin area by the same amount. So the wing root is 1.5" farther lateral to the midline, as is the landing gear fitting. Their relative positions to one another is unchanged--they're simply 1.5" father away from the midline.

Come on; are you just teasing us? 6’4”, 265 lbs., wanting to fly side by side with your wife and with 2 dogs in the back?!?

Nope--it's all the truth. Call me crazy.

I’m sorry, but a 160 hp 2x2 simply isn’t the airplane for you. Nor is a 12 or 18. IMHO, of course.

Not sure why--I spent 1000+ hours giving dual, most of it in older 145-hp or 150-hp powered units, that are only slightly larger than the 2+2 is in its stock (ie; per-plans) form.

It doesn’t sound like you have to pinch pennies, so why don’t you just buy the nicest 180/185 you can afford and be done with the idea of building a marginally less cramped, underpowered rag wing?

Well, thanks for that but our retirement advisor would likely disagree, lol. Are you in the business? Maybe we should talk...

I used to fly for the state of WI and have a fair bit of time in a C-180, and then (part-time) in a C-185 for a construction company on the side. I also got a float rating in a 1954 or 1955 (it was the first year they were made) C-180 on Edo 2425 floats. Step turns in that thing: Yee-haw! That'll really separate the men from the boys!

Back to the 2+2 though--I would really like to build something, and I really *don't* want a certificated aircraft any more. For 10 years I owned (and maintained) an Aztec, which was a major PITA to be honest. I think I spent 1500+ hours working on the thing and 150 hours flying it? Something like that. Every time you turned around though there was some sort of issue. Part of that was because it was a twin (why buy one set of fuel lines, when you can buy two at twice the price?!?), and part of that was because it was a certificated aircraft. Did you read what I said earlier about the price comparison between a certificated G3X and its Experimental brethren? That's just one example.

Thanks for your post.

TB

 

[CamTom12]

Yeah, I actually have plans for the Patrol. Nice aircraft--but the two-seater is something we're not interested in right now. I've sat in the 4-place, and it's too small for me. The 5-place is a LOT of aircraft, although admittedly you could just make it into a bit of a "stretched" 4-place I suppose, to get back some room. Not sure of its width though, as I haven't seen data on that.

Here's the problem(s) with the BH series of aircraft, as I see it:

1) Complicated wing construction for scratch builders
2) Single source of kits for buying what you don't want to build

I've talked to Mark Goldberg several times, and also to (designer) Bob Barrows. Great guys--no complaints there. However Mark's source for all the kits is in Mexico, and they can only do so much. Last I heard they were 18-24 months out on many things, but that was a few months ago. I'm not in that world though, and don't keep up with their status. They might be shorter now.

With the Piper-style builds, there are multiple sources for EAB stuff: Univair, Javron, Dakota Cub, Airframes Alaska, etc. A bunch of others too, I'll wager. So you build what you want to build, and then when you want to buy something to save time...there are often several options in terms of who to buy from. It's not so much of a "cost" thing as it is an "availability" thing.

So although I've looked at them quite a lot actually, I believe I've decided against the BH. Come to think of it...can I interest you in a "lightly-used" set of Patrol plans? ;-)

LOL!

Thanks for your post.

TB

No worries!

And no thanks, I think if I build it’ll be a 4 or 5 place in a kit. I like putting stuff together but I like flying, too. A QB kit costs more but would get me flying a lot faster.

 

[tcbetka]

Not really...at least if Mark's guys are still 18+ months out. It's certainly possible that they've caught up a bit, because a Patrol builder friend of mine said they put on more guys down there. So I don't know where they're at now.

I could certainly handle building the BH wings--but it would be a LOT of work. There's a dude building a 4-place and documenting it on his YouTube channel, and someone asked him (in one of his later wing videos) how much time he had into that first wing. His answer, as I recall, was somewhere around 1000 hours. To build ONE wing. That said I'm sure it would take less time to build the second wing--but that's a very labor-intensive process when you look at hydroforming all the ribs and such. It's also quite possible that Mark could get you ribs more quickly than other parts, because my understanding is that he has those out-sourced by someone out West. I've heard that Van's RV makes them for him, but I cannot confirm that as I've never discussed it with him.

The 5-place looks like a fantastic bird though--if you want something that burns that much gas. I really don't at this point in my life, which is why we might be just fine with an O-320 Lycoming engine. I wouldn't be opposed to using an O-360, but as I mentioned above--I'd be tempted to do the math and then lengthen the fuselage slightly to offset the extra weight. Or at the very least, I'd want to increase the size of the tail feathers by 10% or so, as many guys have mentioned.

I have no criticism about the BH-series of aircraft though: They're just not right for my mission though, at this point in life. But if I was looking at building a 2-seater, I would indeed go after that Patrol. But who knows--maybe the wife will change her mind about sitting in the right seat (and taking the dogs)? The cockpit room in that thing is fantastic, if you're into a tandem-seat aircraft.

TB

 

[CamTom12]

Not really...at least if Mark's guys are still 18+ months out. It's certainly possible that they've caught up a bit, because a Patrol builder friend of mine said they put on more guys down there. So I don't know where they're at now.

I could certainly handle building the BH wings--but it would be a LOT of work. There's a dude building a 4-place and documenting it on his YouTube channel, and someone asked him (in one of his later wing videos) how much time he had into that first wing. His answer, as I recall, was somewhere around 1000 hours. To build ONE wing. That said I'm sure it would take less time to build the second wing--but that's a very labor-intensive process when you look at hydroforming all the ribs and such. It's also quite possible that Mark could get you ribs more quickly than other parts, because my understanding is that he has those out-sourced by someone out West. I've heard that Van's RV makes them for him, but I cannot confirm that as I've never discussed it with him.

The 5-place looks like a fantastic bird though--if you want something that burns that much gas. I really don't at this point in my life, which is why we might be just fine with an O-320 Lycoming engine. I wouldn't be opposed to using an O-360, but as I mentioned above--I'd be tempted to do the math and then lengthen the fuselage slightly to offset the extra weight. Or at the very least, I'd want to increase the size of the tail feathers by 10% or so, as many guys have mentioned.

I have no criticism about the BH-series of aircraft though: They're just not right for my mission though, at this point in life. But if I was looking at building a 2-seater, I would indeed go after that Patrol. But who knows--maybe the wife will change her mind about sitting in the right seat (and taking the dogs)? The cockpit room in that thing is fantastic, if you're into a tandem-seat aircraft.

TB

Yeah, agreed on the complexity - that’s why I’d plan a quick-build kit!

For me though that decision point is a number of years away. My kids won’t even get to college for another 15/17 years or so.

 

[tcbetka]

If you have the money to buy them, the QB kits would be the way to go...certainly. I've seen the quality of the parts coming out of the factory down there--it's very nice indeed. I certainly wouldn't complain.

 

[Paul Heinrich]

If you widen the fuselage 1&1/2” at the top won’t you have to worry about the twisting and folding resistance/strength of the roof and wing support structure? So, too, at the bottom regards the landing gear and seat support structure? AND you won’t be able to just add length to the landing gear struts and Cabane Vee but also have to change the geometry, and that of the landing gear, itself. Won’t both lateral folding and side loads on the gear and fuselage be affected, too.

Wouldn’t widening the fuselage also affect airflow over the horizontal and vertical tail structure/controls and the plane’s pitch and yaw characteristics?

i wish I knew the answers. Maybe your computer design program does and everything is okey-dokey. Good luck regardless.

The most important thing you should take away from my comments on this website is that I am almost always wrong.

 

[DENNY]

If you do a side by side I would do yokes and not sticks. It is just a lot easer for getting in and out especially when you get older. Fuel burn is usually less with a 0360 for given speed. You can get them pretty light with the non metal props. DENNY

 

[Farmboy]

Lots of long posts here but I’ll give a couple of opinions too, based on my experience flying the model 5 and the Bearhawk Patrol, respectively 100 and maybe 150 hrs each.

Yes lead times are long. But stick building is long. There are 30 yr old fabricators that are working 40 hrs a week stick building and taking over a year. The reality is stick building is, for the majority, a 5-10 year build.
Kits are about 2 years out. Maybe a touch less. Add 1.5-2 years at an easy pace if you’re not also working 40 hrs at another job, and you’ve got a finished flying airplane. Go have fun.

Big airplanes need big engines. There are plenty of disappointment pilots with big airplanes being pulled around with o-360’s. If you want a 4 place airplane, build one with the power it likes, and fly it slower to save your fuel. When I fly a model 5 at 80 mph in formation with a bunch of little cubs, I burned 5 gal/hr. Max burned at cruise for my wallet was 13.6 for a long haul, at 135 mph with up to 6 seats. But the width of speed and fuel burn capability is what makes it work.

I am building a patrol because it’s the closest thing to a perfect airplane for my mission, right now. If I had the funds or a family that flew, I’d own a model 5 in a heartbeat. I’d configure it as a 4 place with room to carry the kitchen sink, and ideally put it on Amphibs as it would be awesome in that role. But alas, I’m just a poor farmboy and one airplane is all I get.

Parting note… one advantage of a Bearhawk kit is you get to be more involved in building it then other kits, so lots of room to personalize it. (Although wings are 75% complete and fuselage is fully welded). This is a negative to those prefer to assemble only, but it’s what it is.

Pb


Sent from my iPhone using SuperCub.Org

 

[tcbetka]

If you widen the fuselage 1&1/2” at the top won’t you have to worry about the twisting and folding resistance/strength of the roof and wing support structure? So, too, at the bottom regards the landing gear and seat support structure? AND you won’t be able to just add length to the landing gear struts and Cabane Vee but also have to change the geometry, and that of the landing gear, itself. Won’t both lateral folding and side loads on the gear and fuselage be affected, too.

Wouldn’t widening the fuselage also affect airflow over the horizontal and vertical tail structure/controls and the plane’s pitch and yaw characteristics?

i wish I knew the answers. Maybe your computer design program does and everything is okey-dokey. Good luck regardless.

The most important thing you should take away from my comments on this website is that I am almost always wrong.

Well, this is part of the reason we use software like Solidworks...to look at the statics forces (tension, compression, moments) on the structure.

Your argument assumes that the structure, as designed, is *just* strong enough to withstand the forces it was intended to handle. In actuality there's a safety factor built in, and you'd certainly be eating into that. But by how much? Good question. Given that Wag Aero pretty much just copied a Part 23 airframe, one would assume that Piper had engineered this airframe sufficiently, with a safety factor. And keep in mind: This was with 1025 mild steel tubing, whereas I'll be building this entire airframe with 4130 chome moly. If you look at the mechanical properties of each, 4130 is WAY stronger. So simply put, I wouldn't be at all concerned with going out an extra 2-3" in width, as we've been discussing. That doesn't mean I wouldn't use Solidworks to look at the design and run some static load simulation analyses, just that I wouldn't expect to see any problems.

Having said that, I did order some pa-14 drawings (including the pa-14 fuselage drawings) from Cub Club today so that I can compare the Piper airframe with that of Wag Aero's version. Did Wag Aero beef up the Piper design from the get-go, for instance? Off the top of my head I wouldn't think that widening the fuselage 2-3" total would have a significant impact on airflow over the tail, laminar flow from the slipstream being what it is. The point about the tail is well-taken though, and as I understand it the Airframes Alaska 4-place SC requires a squared-off tail...presumably to increase surface area of the horizontal stabilizer more than anything.

As for the increased buckling tendency(s) at the top and bottom frame, you could always go up one tube diameter to add an additional safety factor if it was necessary. And most builders I've seen always put an 'X' cross-brace in the top structure, from the left main spar fitting back to the right aft spar fitting. That's 1" x 0.049" tubing up there as I recall, but I'd have to check the plans again to be sure. But the point is that you're going to be adding a tube up there anyway--so going up one size in diameter in the tubing between the gear legs should also help to regain your safety margin. Again though, this is the sort of thing that some static analysis with Solidworks will help determine. A guy can also call Kirk Ellis or Jay at Javron, and ask if they've had to increase the size/thickness of any of those tubes.

The last thing I'll add is that I've seen a fellow here in the forum mention that his 2+2 was a full 45" wide! That's one of the reasons I started this thread though--because several people seem to suggest that they'd like a wider version, but no one has really given a good idea as to a justification to go out to a certain width. In other words, for the default airframe design, how wide is too wide? I think there's a reasonable possibility that we would have heard about someone going "hog wild" in widening one of these things, and then having a structural failure in flight. I haven't heard of such an event, but a Google search or two might be in order.

TB

 

[tcbetka]

If you do a side by side I would do yokes and not sticks. It is just a lot easer for getting in and out especially when you get older. Fuel burn is usually less with a 0360 for given speed. You can get them pretty light with the non metal props. DENNY

Good ideas: I know the Catto props are pretty nice in that respect too, and as I recall...not too heavy.

 

[tcbetka]

Lots of long posts here but I’ll give a couple of opinions too, based on my experience flying the model 5 and the Bearhawk Patrol, respectively 100 and maybe 150 hrs each.

Yes lead times are long. But stick building is long. There are 30 yr old fabricators that are working 40 hrs a week stick building and taking over a year. The reality is stick building is, for the majority, a 5-10 year build.
Kits are about 2 years out. Maybe a touch less. Add 1.5-2 years at an easy pace if you’re not also working 40 hrs at another job, and you’ve got a finished flying airplane. Go have fun.

Big airplanes need big engines. There are plenty of disappointment pilots with big airplanes being pulled around with o-360’s. If you want a 4 place airplane, build one with the power it likes, and fly it slower to save your fuel. When I fly a model 5 at 80 mph in formation with a bunch of little cubs, I burned 5 gal/hr. Max burned at cruise for my wallet was 13.6 for a long haul, at 135 mph with up to 6 seats. But the width of speed and fuel burn capability is what makes it work.

I am building a patrol because it’s the closest thing to a perfect airplane for my mission, right now. If I had the funds or a family that flew, I’d own a model 5 in a heartbeat. I’d configure it as a 4 place with room to carry the kitchen sink, and ideally put it on Amphibs as it would be awesome in that role. But alas, I’m just a poor farmboy and one airplane is all I get.

Parting note… one advantage of a Bearhawk kit is you get to be more involved in building it then other kits, so lots of room to personalize it. (Although wings are 75% complete and fuselage is fully welded). This is a negative to those prefer to assemble only, but it’s what it is.

Pb


Sent from my iPhone using SuperCub.Org

I would scratch-build the fuselage, tail feathers and gear...and then buy a wing kit from Javron or D&E, depending on what airfoil I wanted. If I got the wing kit from Jay though, I'd just buy the assembled one. Since I would be building virtually the rest of the aircraft, I shouldn't have any issue clearing the 51% hurdle--especially when you consider that many guys are getting the QB fuselage/wings packages. If they can clear the bar, then I would have nothing to worry about.

That Bearhawk 5 looks like a BEAST though! Very nice aircraft, to be sure.

TB

 

[DENNY]

The 4 place supercub has bigger tubes and a truss type strengthening between the gear fittings. It is a very strong looking fuselage. DENNY

 

[tcbetka]

The 4 place supercub has bigger tubes and a truss type strengthening between the gear fittings. It is a very strong looking fuselage. DENNY

Yup, now that you mention it there does seem to be a trellis structure across the forward and aft door posts:

They also comment on it and the tube sizes (7/8" and 1") here as well. They mention the trellis under the rear seats, but the video I posted above seems to show one under the front door post as well. (Note: I tried to queue up the video right to that point, but it doesn't work embedded in this post...so go to 2:11 in the timeline.)

I'd like to see the pa-14 fuselage drawing, but the 2+2 plans call out some pretty beefy tubing up between the wing roots, and even beefier stuff under the floor. No trellis-type structures down there though.


Do you happen to know how much heavier the tubing wall is Denny? Also, if you know, what's the gross weight of that thing? Is the PMA'd fuselage engineered the same as the Experimental one?

Thanks for the post!

 

[tcbetka]

In this video, they mention at about the 3:06 mark that the airframe designed was tweaked to enable the modifications required to make the doors very large.

 

[DENNY]

If you want to build a 4 place THIS IS THE MAN YOU SHOULD PAY ATTENTION TO!! I would use stock wing/gear attachments and add a Javron wing incidence change. If you change the wing incidence you should also change the tail but a bit of math will do the job.
DENNY

 

[tcbetka]

If you want to build a 4 place THIS IS THE MAN YOU SHOULD PAY ATTENTION TO!! I would use stock wing/gear attachments and add a Javron wing incidence change. If you change the wing incidence you should also change the tail but a bit of math will do the job.
DENNY

Yeah, but that's if you want to build a Supercub-type aircraft...right? Do you think you need to mess with the AOI for a pa-14 replica? I can see squaring off the tail a bit to gain a (relatively free) increase in surface area back there, and I can certainly see using stock pa-18 gear, and a Javron wing. But if a person decided to start messing with the AOI of the wing and also started to beef-up the fuselage under the floor like was done in this 4-place SC, then he might just as well build a 4-place SC. Problem with that though is where do you get the plans? Does Kirk sell them for people to do an EAB with? I guess it wouldn't hurt to call him to inquire, but my impression was that the plans weren't available--hence the choice of going with the 2+2 if you wanted to build a 4-place. If a guy wanted to buy one, then just get Jay's 4-place SC fuselage and build one of his aircraft. However I'd like to build something.

If I'm not careful Denny, you're going to have me in a Javron wide-body pa-18 replica. :lol:

TB

 

[skywagon8a]

I've been reading this with interest, since when modifying an airplane hopefully to make improvements is discussed my brain becomes activated. I have been a long time 180/185 owner and am not a large person (tall but not wide). I would not want a widebody person sitting next to me for more than a quick trip around the pattern. There is just not enough room to move the controls, particularly the flap handle. The 180/185s are nice airplanes, but tight. Rather than asking and thinking about 2", 3", 4" or whatever inches wider, why don't you and your wife put on your winter clothes, set two chairs side by side at a spacing which is comfortable on the living room floor next to a wall? Move your arms around as though you were operating an airplane. Then measure across your shoulders, add some distance for shoulder room at your sides. Use that number for the measurement of the inside of your new fuselage. It sounds as though you are comfortable with Solidworks (I wish I was). Continue as you have discussed.

As Farmboy mentioned, go with the larger engine. You can always pull the power output back, you can never push it up when it isn't there in the first place. Though I would stick with 4 cylinders.

Using larger control surfaces would make the control pressures lighter and provide a bit more stability but they do not offset an out of balance airframe. Add a few inches to the length if necessary, also consider a small amount of ballast if need be. Consider battery location for cg control during your design phase.

 

[skywagon8a]

A quick W&B calculation change of lengthening the fuselage 10" would move the CG aft 0.7". A little more if you consider the extra materials required to make the alteration.

 

[tcbetka]

We've been in a number of C-172 and C-180 aircraft over the years, as I used to give her flight instruction (that's a whole other thread...). I also taught my dad to fly in an O-300 powered C-172 as well, and he was a big guy across the shoulders. It was tight but do-able, given the sliding seats in the cabin. I certainly wouldn't want a 2+2 fuselage to be any *smaller* than that was--which I think is about the same as the 2+2, given the larger trim used by Cessna. My wife and I fit OK in the same C-172 though, and quite possibly still would.

That said, I really was hoping to not have to re-engineer an aircraft design for this project. I started the thread in the hopes that someone would say... "Yeah, I think 2 inches more width would work fine." Maybe that was naive thinking though, I admit. Interestingly enough the thread has given me lots of other things to think about, and thinking about them I am...

Thanks for the post.

TB

 

[tcbetka]

A quick W&B calculation change of lengthening the fuselage 10" would move the CG aft 0.7". A little more if you consider the extra materials required to make the alteration.

I guess I'd have to see your math on that, and of course it would depend upon which engine/prop you had up front as well. That's not all that significant--but it would sure add nicely to the lever given by the rudder & elevators.

EDIT: Almost forgot -- you mentioned that you wished you knew Solidworks. Well if you are an EAA member, I believe you can still get an educational license included with your membership. You have to uninstall and reinstall a new version each year, but that's relatively trivial. There are excellent learning resources for free on YouTube though (as well as paid resources in other places also), so for EAA members the tool(s) is readily available.

I have been using Solidworks now for nearly 7 years and would be happy to help out anyone that wants to learn more about it. It's incredible software.

 

[skywagon8a]

Keep in mind what structural loads would be altered if the fuselage width were changed. Primarily it would be the column strength of the cross tubes where the wings attach and the tensile strength of the cross tube where the wing struts attach. All others are just basically fillers with respect to changing the fuselage width.

What alloys are used in the original 2+2 or PA-14 fuselage? 1025? Just changing to 4130 would answer your questions. Otherwise just increase the wall thickness of the pertinent tubes.

 

[skywagon8a]

I guess I'd have to see your math on that, and of course it would depend upon which engine/prop you had up front as well. That's not all that significant--but it would sure add nicely to the lever given by the rudder & elevators.

EDIT: Almost forgot -- you mentioned that you wished you knew Solidworks. Well if you are an EAA member, I believe you can still get an educational license included with your membership. You have to uninstall and reinstall a new version each year, but that's relatively trivial. There are excellent learning resources for free on YouTube though (as well as paid resources in other places also), so for EAA members the tool(s) is readily available.

I have been using Solidworks now for nearly 7 years and would be happy to help out anyone that wants to learn more about it. It's incredible software.

All I did for the W&B calculation was to change the arm of the tail weight using the same weight of an airplane in my computer. This simulated a longer fuselage.

I am a long time EAA member #7477 and did try the Solidworks. I've also in the past tried other programs. It's just not something I'm able to master. I bought my first computer back in the early 90s with the idea of using it for drafting purposes. All I managed were a few simple drawings. I guess I just don't have the patience for something which is just electrons out of sight until it appears on the screen in a different pattern than what I anticipated.