Bearhawk STOL mods

[stinger]

Wow, right on Brooks! people forget the Bearhawk only has one wing strut. The loading on the aft wing spar and ribs with flaps is significant. Yes the skin and ribs are carrying a lot of the twisting motion to the main spar. One Strut . Stinger

[Franky139]

Nothing is done yet , i'm still looking, thinking and evaluating, the other thing is weight, 1350 lbs is my maximum for empty weight with an angle valves on the nose.

Franky

[Nev]

Hey Bobby, did you manage to get a slightly lower stall speed with power on ? I found mine was losing elevator authority at CG forward of 15 inches. I could get it to stall just around 38 KTAS at light weights and forward CG (F3 or F4), by keeping power on. The power on gives airflow over the elevators and keeps them active, allowing the wing to stall first. If the CG is aft of about 15 inches, then the wing will stall first with power off.

[Daniel]

Don't forget the crew he has working on his stuff for him day in and day out. It's not just about the $$ and equipment. One person cannot do what he does in the time he does it.
Good luck with mods!

[Franky139]

Guys

You are all right in yours comments and they are welcome, i should have start by telling you who i am: helicopter and fixed wings pilot with ATP licences, 18600 hrs of flying, first job was as a machinist, i became a pilot a few years later, i have built a Cyclone airplane in the 90's, it was a copy of the old Cessna 180 in kit form, the main difference was an extra foot of wing at the
root, giving us an extra foot of flap, we also add a cuff on the leading edge wich was a copy of the Horton stol kit at the time, theses mods made a big difference we could take off in about 200 to
300 feets depending on how loaded we were.

I'm half retired, i still fly helicopters on a contract basis and building another airplane is my retirement project, i have a Citabria fuselage and the set of spars mentioned above, In canada, we can used an existing fuselage for a project, as long as we comply with the 51 % rules, my first idea was to build a Super Cub wing or buy the Ribletts ribs made by D&E Aircraft in Florida but when
i've heard about the Bearhawk Patrol and the performance that they were getting with it, i tought myself: This it, i will put this wing on the Citabria so here i am,

My best buddy's son is an aircraft engineer (a real engineer, not just a mechanic) he can do the necessary structural analysis for me, i can do most of the necessary parts with my lathe and my milling machine, i' guessing you all know Mike Patey with his Draco and Scrappy airplane, well, i'm a bit like him, but without the big wallet and the CNC equipments.

I'm not 100% in that project yet, this is why i'm here to get as much positive or not so positive comments before jumping into it.

[Bcone1381]

Hi guys

Check it below and let me know what you think.

Franky

Franky;

Here is what I think.

Experimentation is exciting to me. I really look up to fabricators! You guys build really efficiently. I mean fast and good. I see industry best practices come from Fabricators. Being a machinist/fabricator you have decades of skills, background, tools, to visualize and build. Retirement.....now its time to experiment on fun stuff!! I'm curious what you will find out.

I think you see a lot of good stuff in the Bearhawk Wing design. I think a flap with some fowler action would improve it. I like the Cessna flap action but your drawing is innovative!

It seems like the dimensions of your spar webs will allow you to design a new wing. The flap you designed plus your spars moves the wing away from the Bearhawk prints so this will be your wing, not a modified Barrows Wing. I'm thinking a new flap design would produce different (higher) loads on the rear spar. So thats an engineering problem to investigate, measure, build and break so determine streangth needs.

The Barrow Wing on the Patrol, Modle B, Companion and Five has a main spar dimension of 8.25". Thats about 1/3 thicker than your spar. We get good speed with that thick Riblet Airfoil. That kind of jumped out to me.

I highly respect what Jared said. Are you a designer, builder or flyer? There are enough Bearhawks on floats to determin if the stock wing will meet your expectations. But that might not meet your goals if you are a designer.

[jaredyates]

I think you are underestimating the level of engineering that this mod is going to require, all the while solving a problem that isn't a problem.

[Franky139]

Yes the Husky flaps are differents and much simpler, the similaritee is that they open lower like the ones above, i see the ones above as acting a little bit like the double slots flaps, for sure not as efficient but much less easier to fabricate.

Adding a longer wingtip will give you more wing area but will not decrease the stall a lot, improving the flaps will do much more for reducing the landing distance, my wings are not built yet, i have a set of 17 feets spars that i'm planing to use, they were made for a beef up Super cub (see below) so not much work for me the make a longer wing, the other thing is that i'm a garage guy, and i enjoy building things.

[Utah-Jay]

Have you considered adding wider Horner wing tips, rather than building longer wings, it would be a lot easier.

I think robcaldwell is the person to ask about this. I too think the longer tips are way better rather than redesigning wing control surfaces

[Hewko]

Have you considered adding wider Horner wing tips, rather than building longer wings, it would be a lot easier.

[kestrel]

i am very tempted to modify the flaps a little bit and make thems more like the Husky ones

That doesn't look much like a Husky flap. The Husky flap is very, very simple in comparison.

Warning: Incoming!!!

[Bdflies]

Warning: Incoming!!!

[Franky139]

Hi guys

I am just at the beginning of my project, nothing done on the wings yet, i'm from Canada and what i need is a decent bush machine, i seriously considering building my Bravo wings at 36 feets,
so longer flaps and longer ailerons, it will be on amphib floats so i will loose on top speed to begin with, since i'm not an engineer, even less any big knowledge in aerodynamics, i think i will just keep the proportion of the ailerons and the flaps lenghts of the standard Bravo plan, however, i am very tempted to modify the flaps a little bit and make thems more like the Husky ones, i have
found a design online that is quite interesting and i think it can easily be adapt the Bravo wings, i'm a former machinist and i have a lathe and a milling machine in my garage, i can make the necessary parts myself.

Check it below and let me know what you think.

Franky

[AlexJ]

That is one Gorgeous bird!

[Battson]

It's probably a trade-off, if the hinge is aft then the flap moves rearward, which is good. If the hinge if forward, then the flap moves downward, which is good. NACA determined something along the lines of, the best gap size to maximise lift is 2% cord. So that needs to be factored in as well.