# Neglected homebuilt niche?

Discussion in 'Hangar Flying' started by cluttonfred, Dec 8, 2017.

1. Dec 8, 2017

### cluttonfred

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The PGK-1 Hirondelle discussed in other threads got me thinking about a modest E-AB two-seater optimized for smaller engines, say 100-125 hp. There seems to be a gap between the LSAs with 80-100 hp Rotax 912 power and the RVs and others usually sporting 180 hp or bigger Lycomings with a few exceptions including the RV-9, which is limited to and optimized for the O-320 at the most.

Looking at the Vans specs, even they seem to suggest that in many cases an O-235 would work just fine and be cheaper in the long run for some of their designs, yet you don't see many such installations. Then again, if I remember correctly, some designs like the Lancair started out with O-235 power but quickly moved on to larger engines.

Do folks think there would be interest in a new E-AB (not LSA) design along the lines of an RV-9 "light," in other words, optimized for good performance on an O-235 at the lowest possible cost, or does the "bigger is better" approach mean that homebuilders wouldn't go for something like that today?

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2. Dec 8, 2017

### ScaleBirdsScott

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Well there's the Zenith CH650, Kitfox, Rans, and a few more which is square in that range.

I do think it's somewhat of a pocket, but not exactly neglected?

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3. Dec 8, 2017

### tspear

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Short answer is no. At that point, you may as well trim a little more and go LSA; or go bigger to accommodate the growing girth of pilots.
Besides, not talked about much, there are a number of designs in the range you discuss. And the market has largely discovered why...

Tim

4. Dec 8, 2017

### Toobuilder

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The RV-9 was suposed to be just that airplane, but many are puting 180+ HP on the nose (despite Van's recommendations). Even the "big" RV models (6,7,8) have been supplanted by the newest model, the 14. The 14 is designed for the IO-390 and is a porky beast indeed.

With more than 10,000 RV's completed and flown (and another 10,000 plus in construction), plus all the other homebuilts that started small and efficient (lancair, glassair, eze and clones, etc), I think the market has shown a strong preference for larger engines.

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5. Dec 8, 2017

### BJC

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The RV-3 and the RV-9 both perform well with the O-235. The Lightning supports Rotax 912’s as well as the Lycomings up to 160 HP. Hopefully, someone here with recent, actual cost comparison will tell us what the difference in installed cost is between an O-235 and an O-360 / O-360 clone. My guess is that is is not significant when each is fitted with a fixed pitch propeller.

The first Lancair was the -200. The ads read “buy a run-out Cessna 150, salvage the wheels, engine, instruments, ...”. That lasted about two weeks. The first Glasair, which came before the Lancair, had an O-235. There might have been one customer built with that engine.

I think that it comes back to cost, and I don’t think that there is a big difference, with fixed pitch props.

Having said all that, if someone were determined to develop such an airplane, I would favor a tandem seat low wing, basic aerobatic design. There are existing travelling machines that would accept the smaller engine and provide acceptable performance.

BJC

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6. Dec 8, 2017

### wsimpso1

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The 108 hp of the O-235 is only a little more power and a lot heavier than the Rotax. Next options up are the Lyco O-290 (135 hp) and the Conti O-300 (145hp) and both are getting rare. It is only a small step to the O-320. That is how we end up with so many O-320 powered homebuilts.

All that being said, the Buttercup is out there, with good runway performance on the O-200 and 115 knot cruise speed. Tailwind with O-235 is reputed to be good all around bird if a bit hot on landing, but can manage tighter airports with a climb prop, giving up a little in cruise. Take them up to O-320's, and they can do it all. I do like Steve Wittman's airplanes.

The Long EZ (and its derivative Open EZ) were designed around the O-235, and can deal nicely with tighter runways by making the pitch a bit shorter than is usual. Take them and derivitives up to O-320 and they can do just about all of the pavement out there too.

At OSH last summer, one of the salvage yards was selling complete midtime O-320's for around $10k and IO-360's with prop governors for$14k. You can only get new Rotax and they go $20k+. Not hard to figure out why so many homebuilts that have two good seats and bags and good performance are running O-320's and few are running smaller engines. Billski rdj and cluttonfred like this. 7. Dec 8, 2017 ### TFF ### TFF #### Well-Known Member Joined: Apr 28, 2010 Messages: 11,644 Likes Received: 3,273 Location: Memphis, TN I think in the 60s that was where the focus was. But those were builder homebuilders that wanted to build a plane. Today the RV crowed are betting on a plane that is has fun aspects but is really closer to a certified plane to be used that way. Horsepower race, too. There is no substitute for cubic inches. Tailwind was a C-85 designed airplane; the small version was regularly stuffed with O-300s, so the design was modified and now takes O-360s most of the time. Pitts Special. #1 had a Lycoming O-145. #2 has a C-85. #3-6 either had O-320s- or 360s. What we know as S-!C #1, the first homebuilt for homebuilding, had a O-290 when it was suppose to be a O-200, and O-390s are common now. EZs swallowed the world excess of O-200s. Almost all homebuilts were small and middle engines. What you see today is cost of 912s and O-360s are close enough that the few extra bucks are the difference in settling and having what you want. There is a difference, but if you can afford a 912, you can save one more year and have a o-360. It still is an airplane. No matter how "poor" you are owing an airplane, it is still a "rich" toy, not a life necessities. Maybe perceived as one! LSA is a forced upon category, at least in the US, and only about 15 years old. US people did not want it; they wanted drivers license PPL. The answers of why are only political. Topaz likes this. 8. Dec 8, 2017 ### ScaleBirdsScott ### ScaleBirdsScott #### Well-Known Member Joined: Feb 10, 2015 Messages: 1,034 Likes Received: 656 Location: Uncasville, CT The real difference will be in the guys willing to go for the Vikings and other redrive conversions in the 100-135 HP range with a like-new engine in the sub$14k range. There you can start making a difference.

Still, those planes need to be "designed for 80, stuffed with 150" type situations.

The single-seater I'm working on was designed for 60-85 hp, solid range for availability and plenty for a single-seater, and should be well served with our Verner 5Si. But I'm sure if someone else were to build one as a kit they'll be looking at a Verner 7 @110 hp because it will fit, the weight difference can be compensated for easily, and it'll likely go from projected 1300fpm to something like 2000 fpm. Ultimately it's not a huge cost difference between the two for someone with the outlay for either.

But it's a slippery slope. Start adapting for an extra 20-40 hp and before you know it you've got V8's or bigger hanging off the front.

9. Dec 8, 2017

### mcrae0104

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Matt, what you suggest is what I am working on, with the exception that it is a single seat. Something that lives in between the O-200 class and the O-320/O-360.

10. Dec 8, 2017

### cluttonfred

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Wow, that generated a lot feedback fast. To clarify, what I have in mind would probably qualify as an LSA on weight but be too fast on landing/takeoff and hopefully in cruise, something between a Davis DA-2A and the Hirondelle. A larger wing and/or high-lift flaps could be used to get it down to LSA speeds at additional cost and complexity, perhaps external airfoil flaps (not flaperons) like the on the Miles M.38 Messenger.

The concept here, which is certainly not new, is not just to put in a smaller engine but to optimize the design for lower weight and less power. As Vans has shown, if you design for an O-320 the folks will push for an O-360 anyway, so I would want to stay squarely down in the 100-125 hp range which still offers many options: Lycoming O-235 (and IO-233 if that ever takes off); Continental O-200, IO-240; Rotax 912 ULS and up; ULPower and D-Motor, and various small auto engine conversions.

There is not a big weight difference between an O-235 and even an O-360, but when you eliminate the option of a heavy constant speed prop, reduce fuel to suit lower consumption, save a little structural weight in the smaller wing, it does all start to add up. Keeping the Vans model as a reference, what you end up with is a clipped-wing, no-flaps, Lycoming O-235-powered RV-12 without the LSA speed constraints so landing a little faster but also cruising faster.

11. Dec 8, 2017

### Turd Ferguson

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I like the oleo gear.......must be a European thing.

I first saw a PGK-1 Hirondelle in the flesh early '80's at a local fly-in in the South. Having only seen one in airplane porn mags, I spoke to the builder and found out he was a well known wooden boat builder who claimed he "built the plane while waiting for glue to dry on one of his boat projects." Plane is sturdy and dirt simple. Size/comfort/performance wise it's essentially an AA-1 made out of wood.

Reap what you sow is lost these days. The perfect millennial kitplane would be RV-x styling, handing and performance for Volksplane cost and would require no more physical effort to build than a Sterling Ringmaster. Then you'd have a winner.

So many great airplanes to choose from, so little time.

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12. Dec 8, 2017

### Turd Ferguson

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lol, that's quite the dilemma. Pilot becomes supersized, which leads to poor health and loss of medical so they seek out LSA planes which by design are small and have low payloads.......

13. Dec 8, 2017

### ScaleBirdsScott

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Yeah like I was saying, sounds the goal needs to be "designed for 80, secretly would be killer with the bigger option with some concessions." Then design solutions to those concessions, so that it becomes 'hotrod optimized for 120-ish'

If you know people are likely going to try and stuff it, then plan for it to be stuffed.

It's less to trick people into thinking they're cool for going with bigger engines that are actually still efficient, and more about tricking yourself into not creeping into assuming you'll be able to optimize around 125; because then someone can come in and stuff 180 into it, cuz 'murrica'.

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14. Dec 8, 2017

### Toobuilder

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Look at the T-18, which was designed around the vast supply of dirt cheap surplus O-290G engines. Same concept. Light, simple, cheap. Then the engines started going away and O-360 powered, CS prop equipped, full IFR versions started showing up.

The concept might still work today, but the supply of "substantially" cheaper engines needs to be solid. As soon as you price yourself within spitting distance of a good mid time 360, then that's where people will go. As those versions gain popularity, then the next group will discover it's "only a few more bucks" the get a brand new engine, and then you have the Van's paradigm. Frankly, I believe the idea that airplanes can be "affordable" is lost to the ages. It will only soldier on as a fringe element in the future IMHO. If you look beyond this forum, there is plenty of disposable income in the world.

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15. Dec 8, 2017

### Topaz

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Matthew, you're thinking like an engineer and, in this particular case, that's a bad thing. You're trying to decide a sales perspective based upon what would be most useful to people instead of listening to what people are saying they want. Which latter, very clearly since the late 1980's, has been the biggest engine they can cram under the cowling and into their budget. You've seen the trends yourself: Slick looking airplane is first developed with a smaller, less-expensive engine, and the builders are quickly clamoring to stuff an ever-larger engine into the cowling, right up to the point where the designer says, "Absolutely not! That engine is far too heavy and you'll kill yourself if you try and fly it with that one!" I'm sure Lance Neibauer fended off questions to stuff an O-540 into the original (designed for an 0-200 and then O-235) Lancair. I'm sure some fool tried it anyway. I know for a fact that some fool tried to install a turboprop in one, because I saw the write-up.

Pilots are usually men, and homebuilders are almost exclusively men, and men like "zoom". Oh, there are some that really make rational, logic-based decisions (and every pilot you ask about it will say that he, always makes his decisions that way, just like 80% of people say they're "above average" drivers), but look at what they actually buy and build in by-far the greatest numbers: Hot-rods. "Fast is good," "Faster is better", "Fastest is best". "There is no substitute for cubic inches." What other performance metric do pilots compare besides cruise speed? Climb rate. The other engine-dependent metric. The only "practical" metrics that really get consideration are range and, "Will this thing actually haul my supersized arse and my supersized wife, without having to leave her second set of luggage behind, because she won't go for that?" Other than that, it's "Zoom, Zoom, Zoom," and as much of it as we can squeeze out of the bank account. Maybe we can get a loan for a little more zoom? There's nothing wrong with that, per se, and this has been a very clear trend for decades. If that's what someone wants, and they can pay for it, fine. If that's what someone wants, and they can't pay for it, they'll either max out their credit or wait a little longer, rather than "settle" for an "underpowered little airplane."

That's what people do, which is a hundred-times better indicator than what they say.

Whatever airplane you design, if you intend to sell kits, go ahead and design the airplane to accept much larger engines, even if it's optimized for smaller ones. Your customers are going to push you for it anyway, so you might as well be ready. Optimize the airplane for an O-200 through O-235, but understand that a significant number of your customers are going to be installing O-320's or even O-360's. Make sure the design can handle those engines, in terms of the increased performance, higher fuel consumption, and heavier load. You're going to be doing those studies anyway. Might as well get them out of the way right from the start.

IMHO, there's a niche down "at the bottom" for very light, very small airplanes that can be had on an extremely tight budget. Then there's a thin zone such as you describe, where performance is moderate because the engine is moderate. Several designs there, as others have noted, but I'll also note that many examples of those "moderate" designs have larger engines installed anyway. It was just a cheaper kit. Then there's the bulk of the homebuilt market, where the RV-x's, Glasairs, and so on play. And grossly over-powered (compared to the original) Cub-alikes for those who measure "zoom" in how small a sand-bar they can operate from, etc.

And yet still want as much "Zoom" as they think they can get away with, which is why you see LSA designs clustering right up against, and even surpassing with a "wink wink", the LSA top-end performance limits, with larger engines to carry the "supersized" pilot, his "supersized" spouse/friends, and their "supersized" luggage. The real purpose LSA/Sport Pilot is serving, whatever the FAA's intentions might have been, is for pilots who've lost their medical to keep flying. They'd buy an "LSA" Bonanza if they thought they could get away with flying it.

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16. Dec 8, 2017

### cluttonfred

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LOL, speaking of LSA, I saw a used RV-9A advertised as "sport pilot ready" even though the gross weight is 280-430 lbs over the LSA limit per Vans.

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17. Dec 8, 2017

### BJC

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Several -9’s have been built with the gross weight set to the LSA limit. My neighbor is / was building one, but with Basic Med, he is leaning toward an IO-320.

BJC

18. Dec 8, 2017

### Turd Ferguson

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The LSA -9 makes zero sense because empty weight doesn't change and by limiting gross all it does it make a single place airplane.

19. Dec 8, 2017

### Turd Ferguson

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Lancer, lol, but for a brief time it was the Lancer 200 and Lancer 235, lol.

20. Dec 8, 2017

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