Outsider looking in

[Robngcs]

Hey all, I figured this would be best to post here my apologies if it would be better somewhere else.
So new guy to the forums with an observation.
As I’ve been reading through the forums the past month I am overwhelmed by the amount of innovation all you builders have. I got my ppl years ago and with fam and life flying went to the side but I love reading about it. I have to say this forum is the best I’ve found on guys trying new things and testing them out.
BUT.. the one thing I can’t get past is why when someone asked about putting flaps on the lsa model it gets shot down.
Just something I observed, I could care less either way but a lot of builders call Bob to make changes to designs. If flaps are something someone is more comfortable with why not see if it will work, or putting patrol wings on the lsa, if it would sell a few more models.
Just my 2 cents. I’ve read all about why people don’t need it on the lsa and the 40lbs they would save but builders are already calling the designer to see if mods would work. Why not keep the innovation going?
Yes that one thing made me ponder enough to create an account to post about. Just strange to me I guess, I mean all the other changes are being supported to try yet that single one being totally shot down.
Other than that you guys rock, this has definitely became a favorite to keep reading. Keep up the great work.

Rob

[Battson]

Welcome to the forum Rob.

Intriguing first post, in a good way I guess that's the beauty of homebuilding. We can all have our own opinions, and nobody needs to abide by them

If you or anyone else wants an LSA with flaps, be my guest Just post pictures so we know how it's done!

[svyolo]

I have been on maybe a dozen forums over 20 years, a couple professional, the rest technical. The technical were better. This forum isn't huge, but it is well moderated. Lots of good info. For Aluminum building techniques VAF is huge, as are the systems stuff. Search the forums first, then ask. 90% of the time someone else has asked the same question before.

Welcome.

[Nev]

Hi Rob,

Welcome along, and an interesting observation. There’s always that risk that an idea isn’t well received. I have on occasion had people PM me their replies for fear of attracting negative comments. It doesn’t stop progress, it just stops the sharing of ideas and that’s unfortunate. I often post ideas here, and I’m always interested in all feedback both positive and negative. I simply don’t know enough and the collective wisdom on the forum is brilliant. Good to have you on board!

[jaredyates]

First, let me thank you for the feedback. I hope any time anyone has an idea of how to make the forum better, they feel welcome to express it.
For this particular concern, there is an intentional policy choice behind your observation. With a little searching, you can find many more proposed mods that were received in a similar way. When you say "shot down" I think you mean that lots of folks said why it was a bad idea? Frankly, most of them are bad ideas. But in any case, the goal of this forum is to build community and provide support for builders and flyers of the airplanes designed by Bob Barrows. Even that is a huge mission, and it can be difficult to keep the information "findable" when folks are building according to his designs. It has not been our mission to host discussions about airplane design, which is an expertise that is separate from airplane building. Exceptions to this include discussions about what constitutes design vs building, discussions like this, etc. By popular demand from influential members, we recently created a separate channel for unsanctioned modifications, so that members could talk more about innovative ideas and not confuse folks who are just trying to build the airplane that Bob designed. That channel was probably not active at the time of the flap discussion, it's relatively new. Feel free to start a thread there.
This is an intentional policy choice because we want to foster a culture that appreciates how important it is to build according to the plans, and how even small deviations can have big consequences. We want to ensure that builders coming into the project know that very little in Bob's design is arbitrary, and very little of it can be changed without major ramifications that may not be apparent in the early stages of the project. We have to build judgement within the community about what is building and what is designing.
Just speaking for myself as a builder, I will spare a moment to read what someone has to say about design changes when they have built and flown the airplane, or have serious build/design/fly chops like many of our members do. We gather context about a builder's credentials based on a history of participation. Sometimes it happens that someone who has always had planes with a particular feature (flaps, nosewheel, flying stab) enters the project with an interest in making a Bearhawk-like plane that has that feature, as any "real" airplane does. It is absolutely normal human behavior to have these biases. But experience has shown us that this approach often precludes completion at all, or in cases where the airplane is completed, it produces a less desirable finished product. A great example is when a builder decided to skin the flaps and ailerons with aluminum instead of fabric. After he added enough lead to balance the weight of the aluminum, the airplane had gained 20 pounds and lost some aileron behavior. Needless to say, he didn't fly with them like that for long. I don't offer any judgement about your expertise as an airplane designer, but just offer my experience with having been around this community for a little while, and somehow finding myself with cat-herding powers and a mandate of making the best overall community and archive that we can.
There have been innovations over the years that have been very good, and many more that have been bad. This is the nature of innovation. As for ideas being "shot down",
we don't delete the threads that weigh the merits, because if there are a bunch of replies that explain reasons to not do it, that is the best possible outcome. It saved the builder perhaps thousands of dollars and who knows how much time. Likewise, we don't intervene to require a positive counterpoint to each negative. Usually the reality doesn't provide them anyway. On the topic of deleting threads, this is very very rare from the moderator's perspective, and in the few cases where we have, it has been robot spam or partisan politics unrelated to flying.
Considering the specific question of flaps on the LSA, keep in mind that Bob designed the LSA airframe from the ground up. Every piece of aluminum and every piece of steel is specified to do the job he intended, plus his margin, and not much more. That's what keeps his planes light. Asking the wing attach fittings, strut, and fuselage structure to carry Patrol wings is not in the realm of what we do as builders, that's the role of the designer. Disregarding structural concerns just as a thought experiment, consider the weight. Average the empty weight of the flying LSAs and subtract it from the light sport max gross, assuming you'd want to keep it LSA legal vs the designed max. As with any LSA, you won't find much meat on that bone. How much more does a set of Patrol wings weigh, since they are designed to support 500 more pounds (Patrol 2000 vs LSA 1500), and carry all of the structure to handle the air loads of the flaps, plus the flaps themselves, plus the flap actuation mechanisms? Bob can tell you the weight difference, at least pretty close. We can think of everything in aviation as a cost benefit analysis. What is in the benefit bucket, other than pilot preference/bias, that is attractive enough to take the payload from, say, 375 pounds to 275 pounds? My time in the airplane certainly didn't leave me wishing for flaps, even if the "cost" bucket was empty.
We love Bob's designs because they perform well. They perform well because he designs them well. There is a lot that goes into that.

[Mark Goldberg]

Thank you Jared for your well thought out comments. I will just chime in briefly. We always encourage builders to build as Bob designed. If you go a different path - you then become the test pilot for the new, unproven mods you have done. Having observed things over the years - very few changes to Bob's designs have worked out well for builders. A few have. But almost all have not. Once, a LSA scratch builder was modifying the snot out his project adding flaps and an O320 among other things. Bob became aware of it and asked him to change the name of his plane as it was no longer a Bearhawk LSA. Thankfully, he complied with Bob's request.

On the specific question of flaps on the LSA - I do not recall anyone who has actually FLOWN the LSA say that it needs flaps. Just pilots with opinions (or bias as Jared said) who think it would be good. Mark

[Robngcs]

Wow this got a whole lot more attention then I thought it would. My apologies if I offended anyone. It was just an observation. Without listing everything I read, there was positive talk about building a patrol without flaps. When the LSA with flaps was more like no need to instead of encouraging the innovation like other suggested mods. I could see why someone would want flaps because they’re accustomed to it. To each their own. I am at no place in my life at the moment to build an aircraft. I just think it’s bad ass that guys get a set of plans and start building a plane. I wish I could do that.

Mark- you have a very valid point that if changes are made to the design then it shouldn’t go by the designed name. I have to ask but I don’t blame you for not answering, what did that guy change the name of the plane to?

[Mark Goldberg]

I would not like to give that project any more attention. Apart from the modifications, it has some really ugly workmanship. So it will remain un named. It was started in 2013 and is still not finished. I just looked to check. That's all I will say. MG

[JimParker256]

To Mark's comments, I will add that a lot of that guy's "mods" amounted to a complete re-design of entire portions of the airplane. He also creates a lot of discussion about what are fairly universally accepted as "bad building practices". Honestly, it reads to me like he is "trolling" his own build project... What he's building bears little to no resemblance to Bob's design.

[Enewton57]

As an interesting side note, I remember when I built my RV-6a I called Van’s tech support whenever I had questions about slight changes in the design. The standard response in every case was, “We have never built and tested one that way, so I cannot comment on whether or not it would be safe to do so.”
CYA was the standard response, end of discussion.

Bob on the other hand has always entertained changes, modifications and will spend time discussing the pros and cons of any changes you wish to discuss. I have never gotten a pat answer from him. In fact Bob has spent many hours on the phone and in person with me discussing these things.

Now, having flown the LSA myself, I feel I can comment on the flaps situation. The first time I flew it was at my home airport grass strip. I was alone because Bob simply said, “ get in it and go”. So I did. On my first landing approach, I was WAY too high on short final. As Bob and a bunch of the local pilots stood there watching, I thought, “ crap, I’m going to have to go around”. I remember what Bob told me about how good the LSA slips, I slowed it to 45mph and put it in a full slip.

She came down really quickly and I rolled back straight about a foot off the runway, put it on and stopped before the first turn off. Bob later told me that the local pilots watching were amazed and said to him, “ how did he do that?” Here is the flight report I did:

http://mybearhawk.com/flyLSA.html

just my two-cents worth.

Eric Newton

[davzLSA]

Hey Eric, I have read your LSA flight report several times and I always get a kick out of it, it is inspiration for me to finish mine. I cant wait to get mine finished and see if you are pulling our legs????

[interstate al]

Eric, thanks for posting your test flight report, I enjoyed reading it again. It was this very article that helped sell me on the LSA kit!

[JimParker256]

What I notice about all of Bob's design is that they are generally about as simple as possible while meeting the mission . Simple is lighter. Simple is easier to build. Simple is easier to fly.

I get the feeling that Bob's LSA was designed to fly as much like his other designs as possible, while meeting the specific "rules" that would qualify the airplane to be flown by Light Sport pilots. It met the stall speed requirements without needing flaps - ergo no flaps are "needed" and the airplane can be simpler and lighter without them, giving it more useful load. Adding flaps would have meant beefing up the wing structure to handle those loads, which would mean beefing up the attachment structure, and then the fuselage structure to support that extra weight. The then-heavier design would have required more power (and higher fuel burn) to go the same speed. And all that extra weight would be subtracted directly from the useful load – which is the biggest challenge for ALL LSA designs. You could, of course go with a much lighter structure (a la RANS designs) and give up some of the ruggedness that Bob's designs are noted for... But that wouldn't be a Bearhawk, and it wouldn't fly like a Bearhawk. (I own and fly a RANS S-6, so no hate mail on that topic. It's a great little airplane, and I love mine, But its's just a "purely factual" statement that the Coyote is nowhere near as rugged as Bob's LSA, Patrol or Companion designs. Plus it's a good bit slower than Bob's LSA.)

Sometimes the biggest favor someone can do for us is to tell us when we've gone off into the weeds... Adding flaps to the LSA would likely take the "LSA design" out of the Sport Pilot eligibility category from a legal standpoint. There is a minimum useful load requirement for a 2-seat design based on W&B considerations.

If you really want/need flaps in your airplane, then build the Patrol. The cost difference is pretty small, when you get down to the details... A Patrol powered by the least powerful engine Bob would approve would probably still be a better performer than most of the 2-seat taildraggers out there!