RE: accel hobbies PITTS PROFILE!
 

Hey dhooks, I was just going thru the instruction manual and I have a question. Has to do with the upper and lower aileron push rods. I noticed that there is a bend in the push rod near the upper control horn. Is this bend already in the push rod? This is a strange way to hook the ailerons together. Why was it choosen to do it this way?

Thanks Guys.

RE: accel hobbies PITTS PROFILE!
 

That bend is there to make sure that the rods do not touch the ailerons. That is part of the new procedure. The ailerons are 5 inches in depth, and designed to have extrodinary throw. The rods were touching the ailerons at those extremes.

The rod is not pre-bent, but only a small amount of bend is needed.

Yes, it is a strange way to go about it, but there isn't much about this plane that is ordinary either.

Since you asked, I'll post a picture of mine too. Maybe it will be a little more clear then the small one in the manual. Again, I was able to do mine with the original hardware pack.

RE: accel hobbies PITTS PROFILE!
 

Look at how TT has his setup....

The reason to to it this way is this......if you put the controll horn on the bottom of the top 'ron an top of the bottom one it creates differential in the throw between2 'rons which is not what you want in a serious 3D bird. ( read one moves much farther then the other)

If you dont put the slight bend in the connecting wire it will hit the 'ron at extreme deflections.;)

Was that clear as mud?;)

RE: accel hobbies PITTS PROFILE!
 

Thanks TT. That does explain alot. I understand now.:)

RE: accel hobbies PITTS PROFILE!
 

Good deal, just "hollar", as D says if you need anything...

RE: accel hobbies PITTS PROFILE!
 

Sorry dhooks, I did not see your post before I posted to TT. And Yes that is clear as mud.;)

Thanks Guys.

RE: accel hobbies PITTS PROFILE!
 

Alex responded that any of the orders that are in right now, will ship with the supplamental hardawre following as closely behind as possible.

As I said before, with care, the original hardware can be made to work just as well. The main difference is the shape of the comtrol horns, as I recall. If you want to give it a go, I'll help guide you through the steps I took with mine. Otherwise, the other pieces of hardware are soon to be shipped as well.

Sorry for the delay, and sorry for the confusion.

RE: accel hobbies PITTS PROFILE!
 

I'd use some Sig bipe control horns that way you can run a strait rod or carbon rod the bend looks rigged and easy to knock it out of wack or is that just till they ship the right hardware

RE: accel hobbies PITTS PROFILE!
 

Sig horns would work well...just make sure you mount them on the same side of each aileron IE: bottom/bottom. If you do it top/ bottom you run into tracking issues ( one will move farther then the other)

Prop I had a plane with pushrods that were bent similiar to that an it held up well, I was concerned about it. It does look ungainly though, which is why I prefer bottom/bottom instead of top/top.

RE: accel hobbies PITTS PROFILE!
 

If a person put the slight bend in the bottom part of the interconnect rod, I see no reason why the horns couldn't be mounted bottom/bottom. The function would be the same, right D? Also, mine has the "Z" bend on the top aileron. Hindsight tells me I really wanted the "Z" bend on the bottom and the clevis on top. The only reason is the looks, I doubt any change in performance would occour. Live and learn, I guess.

If you want to try bottom/bottom, just look at my picture, upside down, and copy that instead...;)

I might even change mine around. Just remove the horns, flip the control horns over, then flip the rod over. I might have to try that...[8D]

RE: accel hobbies PITTS PROFILE!
 

I would highly advise against putting both aileron interconnect horns on the bottom, unless you are using the Sig interconnect horns.

First, if both horns are on the bottom, it will require a larger offset bend in the pushrod in order to clear the trailing edge of the bottom aileron when they are fully deflected.

Second, the geometry of the aileron linkage with both horns on the bottom reduces the mechanical force available to operate the top aileron compared to having both horns on top.

With both horns on top, it only takes a small offset bend in the pushrod to clear the trailing edge of the top aileron......even at extreme throws.

Here's a photo of a modified stock top aileron horn on a Pitts. Notice how small the offset actually needs to be to clear the aileron at full deflection.

RE: accel hobbies PITTS PROFILE!
 

Thanks Dr. D!

RE: accel hobbies PITTS PROFILE!
 

Sorry Dave I was referring to the sig horns when I typed that. I havent actually saw the new hardware so I should shut up.:D

Now on the bottom v. top deal talk to me about why it reduces power to the top 'ron by having the horns on the bottom?

RE: accel hobbies PITTS PROFILE!
 

I haven't actually seen the new hardware either. Hopefully there will be some information available real soon about the exact contents of the additional hardware pack.

The real answer to your question would require some geometry, trigonometry, and mechanical force analysis that's probably over my head. So instead maybe these (crude) drawings might help?

Notice the imaginary line that connects the top and bottom aileron hingelines.
Also notice the solid red line that represents the pushrod connecting the top and bottom ailerons. Ideally, this pushrod should be parallel to the imaginary line that passes through the aileron hingelines. And ideally, the pushrod should remain parallel to that imaginary line throughout the entire range of aileron travel.

If the aileron interconnect horn is placed on top of the aileron, the pivot point of the top aileron pushrod remains further away from the imaginary line passing through the aileron hingelines than the pivot point of the bottom mounted horn.

Notice that when the ailerons are deflected down 45 degrees, the pivot point of the top mounted horn still stays further away from the imaginary line passing through the aileron hingelines than the pivot point of the bottom mounted horn.

In fact, with the horns on the bottom, the pivot point of the pushrod nearly reaches the imaginary line passing through the aileron hingelines. The closer the pushrod pivot point comes to this imaginary line, the more force will be required to raise the top aileron. In fact, if the pivot point of the pushrod is allowed to reach that imaginary line, no amount of force in the world can raise the top aileron back towards the neutral position.

This (crude) diagram also illustrates why bottom mounted horns will require a substantial offset in the pushrod in order to clear the trailing edge of the bottom aileron at full deflection.

Did this help? Or was this answer about as clear as mud?

RE: accel hobbies PITTS PROFILE!
 

Man when Dave speaks I often feel humbled.....once again.....;)


Yea the diagram shows it clearly......now just a thought as I type this.....why doesnt the same thing happen with the horns on top when the aileron is deflected upwards?


Note to everybody.....disreguard what I said about horns on the bottom unless you have special horns an understand the limitations of that install.

RE: accel hobbies PITTS PROFILE!
 

The simple answer is because the bottom wing is staggered behind the top wing.

Here's another (crude) drawing that hopefully illustrates what's going on.

Notice the imaginary line between the top and bottom aileron hingelines.
Notice the imaginary dashed lines between the hingelines and the pushrod pivot points.

When the ailerons are deflected upwards, the angles between the pushrods and the dashed lines are close to 90 degrees no matter whether the horns are mounted on the top or the bottom. So if the ailerons only deflected upwards from neutral, it wouldn't really make much difference if the horns were mounted on the top or the bottom......as far as the pushrod forces are concerned.

But having ailerons that only deflect upwards are pretty much useless on a biplane like the Pitts, which was designed for wild aerobatics and 3D.

Therefore the geometry of the downward aileron deflection is what determines the best location for the aileron interconnect horns.

RE: accel hobbies PITTS PROFILE!
 

I completly forgot wing stagger. Someone remind me why I dont design planes.[:@]

RE: accel hobbies PITTS PROFILE!
 

Hmm because theres more stuff to hook up wrong?

RE: accel hobbies PITTS PROFILE!
 

Can you guys that work for Accel Tell me what kind of motor they used in the Video of the Pitts? It sounds cool and lookd to put out pretty decent power.

RE: accel hobbies PITTS PROFILE!
 

There are three separate planes, and three separate pilots in the Pitts video.

The all white Pitts (mine) uses a stock Thunder Tiger Pro 46 swinging an APC 11.5x4.

I'll let the other two pilots chime in on their setups.

RE: accel hobbies PITTS PROFILE!
 

Mine is the one that does the pinwheel. R/W/B. It has a Saito 82 and a 15x4 Pro Zinger.

RE: accel hobbies PITTS PROFILE!
 

TT, I ordered this bird and plan to use the .82 also. Were there any CG issues with the .82? Please explain your CG set up.

RE: accel hobbies PITTS PROFILE!
 

Mines coming and I have the 82 also.Your setup TailTwister would be great info.Thanks in advance.

RE: accel hobbies PITTS PROFILE!
 

My CG is 1.25 inches aft of the leading edge of the bottom wing. The hatch areas are very tight, so my battery is in the hatch opposite of the cylinder head. The switch and Electron receiver are in the hatch on the cylinder side. My CG is there neaturally, meaning no lead or anything. There has been experimentation with CGs from the point of the leading edge (bottom wing) to as far aft as 2 inches. No bad traits, other than increased roll coupling, have been reported. Dave flew the 2 inch aft version and didn't seem to like it much. Maybe he could explain why...

BTW, Pro Zinger 15x4 pulls like mad, and spins up faster than the APC 15x4W. I really like that porp.

RE: accel hobbies PITTS PROFILE!
 

The Saito .82 is currently my engine of choice to.....