Ricmussman

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Hello All,

Is there anyone out there with real knowledge of this plane? I am planning to build one this winter. If yes, please list likes, dislikes, pics, tips..., anything pertinent to a build of one of these. If anyone else is building one let me know we could do a build thread on it. Should be fun, this will be my first large project, I am really looking forward to it.

Rcpilot

My Feedback: (78)

I used to fly at the same club as Mike. I've seen the plane that he built for the magazine articles. I've also seen 2 other planes that guys in that same club built.

They fly SWEEEEET.

DON'T OVERBUILD IT!! He (Mike) did a really good job of designing it to be both light, and strong. One of the other guys in the club that built the plane added a bunch of balsa sticks in the rear of the fuse--under the turtledeck. And he added some ply up in the engine box area. He thought it needed strengthening. He was WRONG. It's 2 or 3 pounds overweight. You don't really notice it. The plane flies great. But the guy is always b***ching about how overweight it is. If he had just built it the way it was designed--he wouldn't be overweight.

I've seen Mike fly the s**t out of his plane. I've seen him slam that plane around like he's trying to break it. I have been sitting back, watching him fly that plane, and I've seen him slam that thing so hard--I though it would explode. He's still flying it today.

Don't overbuild it. It's strong enough.

Donairplane

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Hi,I have plans for this plane, new in tube if someone is interested. PM me if you like. Moving need to clear some things out. Thanks Don.

Tim_Indy

Hey Ric, wazzup?

What engine you planning to use? A fellow club member here in Indy is building one also. No comments from him yet though.

Ricmussman

My Feedback: (24)

Tim,

How are things going? I am planning on a pretty busy building season. I have not yet decided on the engine for the Hurley. It will be a 100cc though, probably the DA or maybe if I could fine a BME 102-105 that would be nice they are much more quiet. I am also building a GP 33%. I am planning on a ZDZ 80 on a can for that. Hope things are going well for you.

Ric

RobT

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My Dad and I both Built one. What are you planning on using it for? IMAC? 3D? Sport?

A DA 100 is THE engine for the plane.

We modified ours so they would accept cannisters as well. We were in touch with Mike through the whole process. He is supposed to be working on a 40% 300 next . . .

Rob

Ricmussman

My Feedback: (24)

I plan on it being my primary IMAC ship, that can do some decent 3D. If I get the DA I would like to get cans for it. If I get the BME 102-05 I will go with the stock setup, it is real quiet. Was the mod for cans tough? What did you do? Could you post some pics? It seems much like a Carden on the insisde and those get cans real easy. I hope that it is not too much trouble.

I am suprised that there are not more of these out there.

Flip and Fly

If you go to this sight, and look under Projects you will find a short review, build thread on the actual plane by Mike him self. http://www.gsal.org/ Good luck, it looks like a good design.

I am making a 35% Extra 260. Using the Cowl, stab, and fin from the Great Planes Extra 330. I was going to build this plane and decided I wanted a 260

1800 sq/in, span 103, length 95. Weight, about 22-23 lbs with the new 3W 80i

I used Sig light Ply, very strong, and very light! Also Sig contest balsa in the wings!

I love this hobby

Flynbulldog

My Feedback: (2)

Hi Guys, Mike Hurley here.
I'd be happy to help if you need anything along the way. The article on the GSAL web page is about seven or eight years old and is the first Extra I designed, a 33% 97" wingspan model. I never had the plans duped and I don't have them any longer. I believe Michael Ramsey, the new associate editor at MA may still have them... Anyway, the model was 20-21 pounds with an original BME 100 (before the 102).

A couple of mods to make this plane fly better: First, Don't add anything to make it heavier, it flies light but the difference between 27 pounds and 30 pounds is night and day. Second If you use the wings from "Flying Foam" make the leading edge stock 3/4" instead of 1/2" and radius the LE at the root no more than 1/2" and taper it down to 1/8th or even 1/16 at the tip. Sharp sharp sharp! The sharp LE will help stabilize the plane in high alpha (take my word for it) and help it to snap better for IMAC. It will exit the snaps much more cleanly and accurately.

The rumor about the 40% is true. I've designed a 40% 300. It is the 2-place high wing design built by Extra just after the 260 and before the 300S. The design is done and it is in line for the prototype stage. It's going to be available as a high quality ARF designed for IMAC competitors and will be marketed and distributed by Aeroworks. It will be their aircraft but I will be involved in the design, prototype and final production decisions. I think we still might be about a year out but I hope its less than that.

Back to the MA Extra if you have any pics of yours when they are built I'd love to have pictures. I have a very small collection of pics from some of the people who've built them so far. If you want to contact me off of this thread (I don't check on here very often) send an email to the addy listed in the SA column of MA.

Good luck and enjoy the build process, it's a lot of work but you'll have a plane you can really be proud of when you are done!
Mike

Flynbulldog

My Feedback: (2)

Also, Don't for get to check our additional notes on the AMA build website. Once the articles were published we couldn't make any updates but as we found things to help builders along the way we added them to the website.

You can access the website here: http://modelaircraft.org/mag/hurley/hurleyindex.asp

And access the additions to the instructions here: http://modelaircraft.org/mag/hurley/corrections.asp

Mike

capngriz

My Feedback: (7)

I've seen three of the Hurley's and one more in progress. None have come close to 27 lbs. The best we've seen is closer to 29, so I suggest you do whatever you can to save weight. It DID still fly quite light, although I did not 3D it much as it was not mine!

Flynbulldog

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Both my original prototype and the one we built in the magazine came out at just a few oz over 27 pounds. A friend here in Denver built two of them in the 26.5 pound range.

Another builder here has built three of them; the first was over 30 pounds. It flew fine but had problems in the snaps and was a little unstable in HA but still very manageable. He always managed to be in the top spots at the local IMAC contests. The next two he built together, one he has not finished but the other is flying at just over 27 pounds. He also sharpened the LE like I suggested. Between that and the lighter weight it really made an improvement. His piloting has also really improved in just a few short weeks. The plane is so stable in 3D that he can now do things he wouldn't have attempted with any of his other planes.

Yep, you can build them at 29 pounds. But if you're diligent they absolutely can be built at 27 or less.

Mike

jeide

My Feedback: (111)

Hi Mike. I'm just about finished with #3. A note to Capngriz, the first 2 Extra's I built turned out at 26.5 LBS RTF. The Hurley Extra's have been really fun to build. Just build it per plans and building instructions and you will have an airplane to be proud of. Jim

RobT

My Feedback: (17)

The Hurley's My Dad and I built came in at 28lbs with Canisters. Since the cans add about a pound that would be 27 if they did not have cans. They fly very well. The 3D is great. The reason I asked if you wanted it for IMAC was already stated my Mike. Sharpen the leading edges if you want it to snap for IMAC. I talked with my Dad as he did have picture of the can instillation and he will try to post them tonight.

Rob

Bobt2

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i have built 2 of these.i planted #! after 150 flights and #2 with the new LE is 2 yrs old with about300 flights. i'll try to dig up pictures. i took a few 2nd places in sportsman with this plane . as a reference i own an aeroworks extra and a carden extra both in 35% and even tho the carden was my mount this year in imac the herley is still the one that always goes to the field. bob t

erjpilot

My Feedback: (4)

Here are some pics of my Hurley Extra. I have been flying it for 2 seasons now and thoroughly love the airplane. It has a DA 100 with standard in cowl mufflers. I built it per the plans and instructions. I used contest balsa throughout and I was very meticulous about keeping the weight down. It came down to weighing every piece of balsa and using only the lightest components. The airplane came out at an honest 26 lbs on the nose. Needless to say, with 2060" of wing area, the airplane flies like a kite. I have 2 more plywood kits that I cut out for this plane and I plan on building another in the future. I want to install canisters on the next one. Mike's comments about the sharp leading edge are good advice. If there is one problem with the plane, it is the original 1/2" blunt leading edge on the wing. It has a tendency to bury itself in a snap and not come out cleanly. My next Hurley will have the sharp leading edge. Thanks for the great design Mike.

rcblimppro

Flip, I have a mold for a 35% Extra 260. It was taken off the PMP 260 and I know it fits the old Pirate models 260 as well. If you would like to see if one would fit your 260 I'm game. It is 12 1/2" wide and 10" tall is two peice.




Shawn Berkheimer

R/C Blimp Productions.com

Flip and Fly

Thanks Shawn, actually I used the cowl from the Great Planes Extra 330. I built my design around that one.

Thanks all the same!

Mike, if you are still there the sharp leading edge sounds like a good Idea to me. I was wondering if on a 260 it would also be of benefit being a mid wing design, anyone. Mike!

I went with a wing that tappers from root to tip, 13% at the root, 11% at the tip.
total span of 103 inches, 1800 sq/in.

Leading edge is swept back 4 degrees from a strait leading edge, ailerons are strait, 3.5 inches wide. Hoping for 22/23 lbs ready to go.

I want it to snap well for IMAC, and still have good 3D. I figure if its light I will do fine.

erjpilot

My Feedback: (4)

Mike,
Regarding the sharp leading edge you are talking about, how are you measuring that radius. Especially the 1/16" at the tip. Are you basically bringing the leading edge to a dull point?
Thanks, Travis

Flynbulldog

My Feedback: (2)

Flip and fly,

What happens is that with our larger planes the real wing loading is so light that some of the rounded LE designs don't want to allow the airflow to separate and let the plane snap. Then when it does let go it tends to be more violent, like winding up a spring, and it doesn't want to stop. Also with a round LE the separation point at any given part along the leading edge tends to vary with attitude and conditions. The design allows it to be totally dynamic, separation could occur at any point along its radius. thus you get rocking. Yes there are a ton of other factors that go into the equation and I'm oversimplifying things a bit.

Remember that both a snap and high alpha flight are reliant on stall performance. Planes that resist stall my be able to fly very slowly but they give you fits once into a stall. That's why some planes with fat round airfoils that are supposed to be designed for 3D don't harrier very well. They don't want to stall.

High wing loading planes should probably not have sharp LE's. Planes meant to fly tight loops or tight turns should not have sharp LEs.

Larger planes usually fly pretty light and when you combine that with a wing that doesn't want to stall you get sloppy harriers and bad snaps. (to a point)

What I'm trying to do is create a design that stalls early and stalls in a predictable and consistent manor. By making the LE sharp you limit where airflow separation is going to occur and create a situation where both wings will stall together provided they are at the same speed and same angle of attack. In a harrier that works to keep rocking to a minimum and gets you into the harrier sooner. In a snap the aoa is increased and the inboard wing should be slowed by initiating rudder so it should stall first and predictably. Let go of the rudder and level out and airflow should reattach helping snap exits.

If I were doing your 260 I'd probably go with sharper LE but I would have preferred a further aft high point. At this point you can't change that but you can sharpen the LE. One thing I'm kind of sticky on is that I like to put my ideas to the test before I say for sure that it's going to work on any particular design so for your plane I'd probably be a little more on the conservative side. You can always add material and sharpen the LE at a later time. (Or round it for that matter) Looking at your pics the LEs don't look overly blunt to begin with. But I don't think it would hurt to sand a little more

Another thing to be aware of when flying a plane set up like I'm suggesting is energy management. You're making your plane snap more easily so if you go grabbing a handful of elevator when the plane is slow it’s going to stall. You need to be aware of that when you fly. The MA Extra does not want to snap so I'm very comfortable telling people to sharpen the LE but I need to know a little more before I'd do it to just any design.

To erjpilot

I’m not really measuring the radius, I just shape it like a 1/2” pipe. At the tip I bring it to a sharp point and ever so slightly sand it so that it will not be so delicate. After the monokote is on it’s surprising how well it holds up to normal use.

Flynbulldog

My Feedback: (2)

Travis,

Your plane is gorgeous! If you can stand it peel the covering back from the leading edges, sand a flat portion on the front and glue about a half inch more balsa on there and create a sharper LE. I'll bet you'll be glad you did it and you won't have to wait for your next plane.

Flip and Fly

Wow, thanks for that very in-depth reply Mike. Now I see the big picture. I think I will take your advice and go sharper on the leading edges, with caution! If I find it too snappy for my liking I can round things out a little at a time.

You mentioned that you would have moved the MAC further back, what would be ideal in your opinion. Also would leading edge sweep not have a effect on the placement of MAC. So much to get a grip on

Thanks for your input, its coming along!

Even if it fly's just OK, ( it will fly) its my baby

Flynbulldog

My Feedback: (2)

Flip and Fly,
Yes, the sweep does change the point of MAC. But remember MAC is a single point on the wing. The high point of the airfoil is not the same as the MAC (Mean Aerodynamic Center). The highpoint goes across the entire span of the wing. It does not need to follow (be parallel to) the sweep nor does it follow any prescribed point. You can design it into a wing to follow the path of your choosing. I like the highpoint to be perpendicular to the airflow. Not everyone agrees with this. The high point on an Edge540 sweeps forward towards the tips. Many Extras sweep rearward like a Giles.

Also realize that NACA airfoils (most common for Scale Aerobatic models) were designed for full scale aircraft, our models have very different requirements. I have found (observed) that an airfoil with a shallow rise (aft high point) tracks better and holds the position and thus the line better. Most NACA foils are at 28% I'm putting mine anywhere from 33% to 37% it all depends on the thickness and the sweep and I may vary them from root to tip. I also rarely use the same airfoil at the root and the tip. It's usually a combination to get the desired overall effect.

Again it seems that the relationship of the highpoint sweep to the LE sweep makes vast changes in performance.
The jury’s still out, that’s the fun part!

Mike

BTW your 260 looks great, and I'm betting it will fly very nicely

Flip and Fly

Thanks Mike, I have heard many debates on that and I see what you are getting at. Its all still a big learning curve for me, its sinking in, very interesting.

When I designed the wing for this plane I used the rib design from the Great Planes Extra 330, just took out the dihedral, and moved the sweep of the wing a little more rearward. I increased the wing area, by adding more ribs to the root, and removed ribs from the tip. The high point on my wing is perpendicular to the air flow. Also the high point on my wing is at about 28% across the span.

I know the great planes 330 flys IMAC well so I felt comforted that things should work fine. Also use the stab and fin from the 330 in my design but increased the rudder, and elevators in size. Also lengthened the fuse.

If I am not happy with the flight of this plane I will make a new wing out of foam, learning how to cut foam with a bow. Does not take too long, and I love to experiment

I have always wondered why the wings on full scale aircraft have the thickest part of the ribs so far forward. It's true that models and full scale behave very differently. I also noticed that some of the Yaks flying at the Tucson Shootout ( I got the movie) had the thick part of the airfoil very rearward as you stipulate

Thanks again!

erjpilot

My Feedback: (4)

Mike,
Well, now you have me thinking about doing the modification to the LE. I guess it really wouldn't be all that hard. I would just have to redo the red monokote on the LE then. Is there that drastic of a change for the better in the flight characteristics?
Travis