incidence angles

[Ernie]

Good morning all.   Can anyone give me incidence and thrust angles for a high wing vintage model (a KK falcon)

ernie

[GrumpyGnome]

Does this help?

 

https://outerzone.co.uk/plan_details.asp?ID=908

[Ernie]

Thanks GG, I've been looking at that site, and it's difficult to enlarge it enough to see any detail. Maybe a junior 60 info would help, the layout is very similar. It's the wing and tail incidence that I really need. Guess wings at +3, and tail at 0

ernie

[Alan Gorham_]

It's not difficult to enlarge if you download the full-size pdf of the plan which is located a long way down the page under the download files bar:

 

 

 

My guess is that you have been trying to enlarge the low-resolution thumbnail at the top of the page.

[Engine Doctor]

6 hours ago, Ernie said:

Good morning all.   Can anyone give me incidence and thrust angles for a high wing vintage model (a KK falcon)

ernie

The incidence angle on vintage plans is often for free flight and generally needs reducing for rc flying unless your ok with holding in down elevator when flying at anything faster than a glide.

[Jim Hearnden 1]

As ED said, free flight models of this period ran a fair bit of wing incidence together with positive tail incidence, often with lifting tailplane sections. This means the C of G is frequently 60-70% or so. Reducing all the incidences & running a C of G around 25-30% makes for a much nicer flying model. Also less "kiting" when its breezy & flying into wind.

[PatMc]

56 minutes ago, Engine Doctor said:

The incidence angle on vintage plans is often for free flight and generally needs reducing for rc flying unless your ok with holding in down elevator when flying at anything faster than a glide.

Nonsense, there's no need, or sense, in changing incidence angles. You have both elevator & motor control. Just don't use a modern day sport/aerobatic power level set-up.

[Christopher Wolfe]

3 hours ago, Jim Hearnden 1 said:

As ED said, free flight models of this period ran a fair bit of wing incidence together with positive tail incidence, often with lifting tailplane sections. This means the C of G is frequently 60-70% or so. Reducing all the incidences & running a C of G around 25-30% makes for a much nicer flying model. Also less "kiting" when its breezy & flying into wind.

 

How does the model know that its flying into the wind?

[Jim Hearnden 1]

44 minutes ago, Christopher Wolfe said:

 

How does the model know that its flying into the wind?

Greater airspeed, so it will generally "kite" into any form of head wind. Assuming the power level & therefore still air speed remains the same, then any wind you fly into will be added & effectively you're flying faster. In a full size you frequently need to change trim from flying downwind and turn into wind.

[PatMc]

2 minutes ago, Jim Hearnden 1 said:

Greater airspeed, so it will generally "kite" into any form of head wind. Assuming the power level & therefore still air speed remains the same, then any wind you fly into will be added & effectively you're flying faster. In a full size you frequently need to change trim from flying downwind and turn into wind.

Sorry but that's absolute nonsense.

[Jim Hearnden 1]

3 hours ago, PatMc said:

Nonsense, there's no need, or sense, in changing incidence angles. You have both elevator & motor control. Just don't use a modern day sport/aerobatic power level set-up.

Depend on what you want. If you leave it as it was then its effectively guided free flight. My view if I'm fitting radio is to fly it as a an R/C model. One group of guys I used to fly with flew with traditional free flight models with RET. I believe they were of the Junior 60 ilk. They struggled when I let them fly one of mine, it was a Yamamoto type trainer and was relatively low powered (Merco 35 I think). But didn't have the super safe, slow flying characteristics of their radio assisted models. 

[PatMc]

What's "the Junior 60 ilk" ?

[Phil Green]

bemused as to why, if you wanted the handling characteristics of a Yamamoto, you would build a Junior 60... 🙂

Conversely, if you want a Junior 60, wouldnt you want it to fly like one?  otherwise why bother?

Bottom line with vintage is not to overpower it 😉

[Jim Hearnden 1]

2 hours ago, PatMc said:

What's "the Junior 60 ilk" ?

Junior 60 look alikes, so late 50's early 60's What would now be called vintage designs but weren't 30ish years ago. 

I don't know why they'd gone this route, they weren't club members or similar. He was my barber in the village and knew I flew RC. that's how I knew him & his SiL.

 

[Jim Hearnden 1]

2 hours ago, Phil Green said:

bemused as to why, if you wanted the handling characteristics of a Yamamoto, you would build a Junior 60... 🙂

Conversely, if you want a Junior 60, wouldnt you want it to fly like one?  otherwise why bother?

Bottom line with vintage is not to overpower it 😉

The issue appeared to be they flew their models in isolation & thought they could fly RC. 

But when given a model that was more mainstream they struggled. For some weird reason they'd bought a part completed DF model with an OS91DF. Not sure RET vintage style stuff will give you the skills you need for that.

Yup don't over power them & use the throttle anyway. Its certainly a different flying experience. 

[Ernie]

Hi guys; love the discussion, but does  anyone know the incidence angles for a KK falcon

ernie

[Phil Green]

They're on the detailed plan Ernie:

https://outerzone.co.uk/download_file.asp?planID=908&FileType=Plan&Filename=Falcon_3_pages_oz908.pdf

 

[Jim Hearnden 1]

35 minutes ago, Phil Green said:

They're on the detailed plan Ernie:

https://outerzone.co.uk/download_file.asp?planID=908&FileType=Plan&Filename=Falcon_3_pages_oz908.pdf

 

Not sure you can hotlink to OZ site Phil. You'll have to go to Outerzone then search on Keil Kraft Falcon

 

Edited September 18 by Jim Hearnden 1
Don't use Keil Kraft!

[Engine Doctor]

It appears a few of  our ideas about incidence and vintage FF models converted to RC is nonsense !  

An awful lot of us have been sucessfully  flying this " nonsense " for many years, and also flew  a Yamamoto mk1 , 2 and the fg version

We all have our ways and means to tackle a problem .

Sorry Ernie never meant to hijack your OP .

 

[Phil Green]

Hi Ernie, I dropped the PDF into CAD and drew a line through the tail datum, this measured 179.5 degrees.

Another line along the wing support longeron shows 180 degrees, so the rail that the wing sits on is half a desgree positive wrt the tailplane.

Now I know this isnt its aerodynamic incidence, but for a build I expect its what you need to know.

 

 

[PatMc]

16 minutes ago, Engine Doctor said:

It appears a few of  our ideas about incidence and vintage FF models converted to RC is nonsense !  

An awful lot of us have been sucessfully  flying this " nonsense " for many years, and also flew  a Yamamoto mk1 , 2 and the fg version

We all have our ways and means to tackle a problem .

 

Step 1 being -

First create a problem where none currently exist ... 🤣

[Phil Green]

Clickable link:

 

https://www.rcgroups.com/forums/showatt.php?attachmentid=3904764&d=1301444585

[Nigel Dell]

Well each to their own but for me a vintage model is radio assist and usually a vehicle for using an ancient engine for that added nostalgia so built as is, want a sports model there are plenty out there.

[kc]

That drawing is good for construction -all parallel to the longeron - but for incidence surely it needs the chord line drawing in and that would be from TE to the LE roughly where the arrow showing fairing piece is pointing.   So a few degrees of incidence.   

Answering  Ernie's question - in practice use the top longeron as the datum for everything and assume the measured 179.5degrees  is possibly an error in measuring or plan copying problem. 

It's difficult to seat an airfoil shaped tailplane to an exact position,  so maybe construct with the centre ribs flattened so they seat nicely.   Probably glued in tailplane will give more consistent RC flying than a rubber banded on one, although crash resistanc, experimenting with tailplane angle and transport/storage will be sacrificed.

[Christopher Wolfe]

Free Flight models are designed to climb (hopefully in a stable manner).

 

Competition I.C. free flight models are designed to climb as quickly as possible within the constraints of of a limited engine capacity, power-on duration along with dimensional specifications.

 

Some designs from over 70 years ago achieved stability by using a rearwards CG (typically 70%+ of the wing chord) and a large 'lifting' horizontal stabiliser to balance the steep spiral climb. A typical example is the San de Hogan from 1949 San de Hogan

'Sport' Free Flight models are usually less demanding and so a stable gentle climb is usually achieved with a design with a more conventional layout and C.G. location with the engine rpm maybe reduced to suit one's requirements.

 

Early R.C. models were basically sport free flight models with the addition of of a rudder which permitted not only turns but also altitude control by regulating the duration of the applied rudder. The resulting spiral dive and increase in airspeed could also be utilised to perform basic aerobatics.

 

Modern re-creations of these early models also exhibit the natural tendency to climb (as it was designed to) and with the power of today's engines it is logical to use a more forward C.G. which along with intelligent use of the throttle and the addition of an elevator can result in a pleasant and easy to fly model.

 

* Chris *