ChrisMH

BVW Update.

Redesign progressing nicely. So far, things are fitting together with minimum tweaking.

Bill, or whoever, does the stab really have +2deg incidence? On the plans I've got, it's more like +1/2 deg.

khodges

My Feedback: (1)

Guys, your opinion on something. I have some sheets of thin, corrugated plastic, the stuff is 0.010 in. thick, but the corrugations aren't as close as I'd really like in order to cover the aileron surfaces. However, they are close. Cut to fit, it comes out to 21 corrugations over the span of the aileron. Here's a picture of a piece just laid on the aileron in position on the wing. Do you think it looks good enough to use? I keep telling myself not to fret the exact rib count (it's only an ARF, it's only an ARF, it's only an ARF) and this stuff would save a lot of labor for a result that might not look any better. If I use it, I'll attach it with 3M spray adhesive. I plan on insetting the control horns so only the linkage arm shows, and this stuff will cover over the screws, etc.

BTW, the ribbed sheets have a Sig part # and come in three "spreads" of ribs. There is one that is actually spaced more closely, and would give a rib count of 27, but the sheets are too small to cover the aileron with one piece. Unfortunately, I have lost the part #'s and don't remember which is which for the particular sizes.

One other thing, and it's been mentioned before, is the thickness of the trailing edge and how the ribbed pieces would look if they don't meet like they do on the prototype. I think it might be okay. (it's only an ARF)

damifino

The model plans call for +2 degress for the H-stab and zero/zero on the wings.

pimmnz

Since we are only looking for the right `impression' of the ribbed ailerons, that plastic sheeting looks mighty fine to me...
Evan, WB#12.

Hughes500E

My Feedback: (16)

Still working hard I see. I have been busy with a few issues these days, just getting back on track. Without reading back, my apology's, I remember chat about proper cowl mounts. I would really like to pick up a set of those made out of SS. I have been drilling SS for my Interplane struts, what a job that has turned out to be!

Any stainless pre drilled cowl mounts up for grabs ?

Stickbuilder

Contact damifino about the stainless mounts. As to them being pre-drilled, how would one go about knowing how everyone has set the model up? There are as many different set-ups as there are builders. Get yourself some good bits and have at it.

Bill, AMA 4720
WACO Brotherhood #1

Stickbuilder

I noticed that the set up on the plan and what the call out is are completely different. But if you start checking measurements on the plan, you will see that some of the dimensions shift between different views too. Take a look at the top crutch view, and the side view. Completely different. I'm making my H-stab adjustable while in the air, and this should take the guesswork out of the equation.

Bill, AMA 4720
WACO Brotherhood #1

flyguy888

My Feedback: (63)

I am really confused about all the stab incidence talk that has been mentioned in the thread.
What is the proper angle of the incidence? And is that incidence in relation to the wings, or center line? And what direction is postive or negative? When you say positive I am assuming the leading edge of the stab is in the up direction? Maybe so maybe not, I dunno. Please clarify.
My head hurts[].

ChrisMH

I have no idea what the correct incidence is On the plans it's called out as +2deg. On the plans, it measures as +1/2deg. I believe it's generally measured relative to the thrust line of the aircraft, but I don't think it matters much so long as the wing(s), stab, and engine all align correctly relative to each other.

Bill, I mentioned a couple posts back the same discrepency that you mention here...the plans are not so good!

Chris

Stickbuilder

Actually, positive incidence means that the leading edge is down, in this instance 2 degrees down, relative to the datum line of the plane (crutch). This is esentially the same as adding up elevator (kinda-sorta) I am going to use an adjustable stab, and will be able to optimize mine in the air. I want zero trim input, and neutral climb and dive at cruise. This will mean either resetting the incidence for landing, or actually flying the model to touchdown (novel idea).

Bill, AMA 4720
WACO Brotherhood #1

Skinny Bob

My Feedback: (12)

Bill, I beg to differ with you. Positive incidence is up!

flyguy888

My Feedback: (63)

Gee, you guys are lots of help. I said I was confused. Thanks for clearing things up.[]
So then is the leading edge of the stab to be pointed up a degree or so from the centerline of the model?

Stickbuilder

I ain't gonna argue about that one... Had my head inserted where it should not have been. I wuz typing while talking to one of the salesmen, and got it bass-ackward. Anyway, I can adjust mine with a servo on the flap channel.

Bill, AMA 4720
WACO Brotherhood #1

Skinny Bob

My Feedback: (12)

Yes, 1 degree + is leading edge up. I had a Christen Eagle with to much top wing + incidence and I had to use about 30% down elevator to maintain level flight. First hand experience.

flyguy888

My Feedback: (63)

Any one else want to verify that the proper incidence is leading edge of stab in the up direction from centerline of model?

ChrisMH

I'ts leading edge up on the plans, although not as much as the callout on the plans.

Every plan I've ever looked at has + incidence meaning the angle above the datum. So leading edge up, engine thrust pointing up, etc.

I believe I may design the thing so that the incidence is adjustable, although possibly not via the radio. We'll see how ambitious I get.

skylarkmk1

To all,

I have been in contact with Bruce Sanders, President, Century Jet Models, Inc. about making main and tail gear for the 1/5th and 1/6th YMFs based on their 1/3rd size Genesis YMF, Bruce said that it would be possible to make in the smaller sizes. We are just in the begining stages of figuring things out and have a ways to go, but Bruce pointed out "The more gear that is ordered at one time reduces the price...". The price still needs to figured out, so I do not have one for you at this time. Hopefully, the gear will be a direct replacement for the Cox/Pica (less any fairings) and only a minor adjustment for the Pica plans builders.

So how many are interested and in what size (1/5th or 1/6th)?

I will also post in the Cox/Pica thread.

Skinny Bob

My Feedback: (12)

I am interested in the 1/5 gear.

Edwin

My Feedback: (2)

Positive incedence on the stab makes sense. The bipe I have and others I've flown needed quite a bit of down elevator trim (about 1/4"). Raising the stab a bit should help that.
Edwin

Stickbuilder

Tell us how it mounts. Pictures would be helpful.

Bill, AMA 4720
WACO Brotherhood #1

skylarkmk1

To All interested in possible CJM landing gear,

From what I have seen of the 1/3 gear, the gear mounts to a plywood plate that is in turn mounted to the fuselage gear blocks. The first picture is the Cox/Pica gear, the second is the Cox/Pica gear mounts and the third is the 1/3 gear mounted to the plate. It is my intention that the CJM gear would mount directly onto the installed mounts in the case of the Cox/Pica and mount to new blocks in the Pica plan built planes. I have expressed this to Bruce at CJM. The last picture is the tail unit (again 1/3rd scale) that would mount directly into the Cox/Pica tail area and from F-14B and F-26 in the plans built. The mounting brackets will need minor redesign so they can be mounted from the bottom. As I stated earlier, we are still working on the design details.

pimmnz

Actually, this incidence thing is easily sorted, If you want to do it with the finished article this is how it is done, though you do have to allow for adjusting things. Set the fuselage up rigidly at the airborne attitude you wish to fly at. With a Robart or similar level set the tailplane level (0 deg. incidence). The engine prop shaft can be set at 0 deg. as well. The two wings can now be set at +1~2 deg positive (Leading edge up) using the chord line as the reference. (Chord line? Imaginary line through centre of L/E to T/E, not the bottom of the wing). Arrange the CG at 25% of the distance from the L/E of the top wing to the T/E of the bottom wing in this jigged position. Now go fly. Minor adjustment may be required, but this set up will mean that the first flight will be stable and predictable. (If you are building, then this is much easier to achieve, no guess work is required).
Evan, WB#12.

Capt Jim

My Feedback: (168)

Regarding incidence. I fly a Great Planes giant Aeromaster, (bipe)...built from one of the early kits...which was a blown up version of the old, and well designed Lou Andrews Aeromaster. The way the story goes....GP apparently goofed on the specs when they blew up the plans. GP claimed the two wings and the horizontal stabilizer were to be zero-zero-zero degrees incidence, as referenced from the thrust line. Mine was built that way, and although it was properly balanced, ... it ballooned like a homesick angel at any throttle setting!!!
The story goes on to suggest that Lou Andrews actually made the wings zero-zero...but the horizontal stab' was to be one degree positive. That would mean that the leading edge of the stab' is UP by one degree. A bit like flying with a little down elevator dialed in.
After the kit is all built and finished, it is extremely difficult to go back and get the stab LE up by just one little degree.
What I did to eliminate the ballooning, was to place a washer, or two, on the wing bolts, under the trailing edge of the TOP wing. It's a quick and easy fix. This made a dramatic difference in the flight characteristics, and the Giant Aeromaster went from handling like a three legged camel...to flying like an average sport plane. Quite a nice improvement. Minor adjustments may be needed on your interplane struts to accomodate the top wings new position, without introducing wing warpage. You may experiment with any number of washers until you get the plane to handle as you might expect it should have in the first place.
Good luck.

ctflyboy

My Feedback: (3)

Members of the WACO Brotherhood:
Today there was a 1/5th scale WACO 72"ws on ebay and I put it a bid for it,and I was the high bidder for most of the day, there was some bidder who kept playing the game by bumping the bid a liitle each time so I put in my maximumbid of $301.00, apparently he wanted it more than I, cause he won the bid it went for $ 305.00
I have never seen one go that High.

George
WACO Brotherhood # 5

bart5495

George,
That was me cityboy. I've been watching that listing for a week. If I knew that it was you ,I would have let you have it. I have lost many of listing thinking that no one else would bid after me and then, only to be let down at closing. I've found that if you place your maximum bid at the begining of the listing it, only jacks up the price sooner and the item goes for much higher. If I had placed a bid of 299.00 on Sunday would you have let me buy it? I hope your not mad at me?

Doug
#11