Don't forget to check your spam folder if you don't get an activation email after joining!!

M100S

Let us all watch your new project progress.
Post Reply
User avatar
RobbieB
Posts: 579
Joined: 07 Mar 2015, 22:22
Location: North West

Re: M100S

Post by RobbieB »

I have been thinking about how to go about the aileron pushrod shrouds on the 100 which are almost certainly glass on the full size:

Carmam-M100-59.JPG

To make such a thin thin walled shroud I opted to do the same. Unfortunately when I opened my bottles of epoxy laminating resin the catalyst was a most definitely 'off' colour.

So, make the plug out of balsa - too small and fiddly to use foam:


shroud_plug.jpg

Pull a small piece of light glass cloth over the plug as normal:

shroud_cloth.jpg

Soak with watery cyno:

shroud_cyno.jpg

Trim off and repeat with second layer and then remove the balsa plug with the Dremel leaving a nice, thin walled, flexible but strong shroud:

shroud_hollow.jpg

That one is a bit rough as it was the first experiment.

The big advantage here is, it's very quick and you don't have the inconvenience of mixing up the epoxy resin or trying to keep the glass cloth in contact with the very small plug while it cures.

I think the real secret of success here is knowing when to put the Dremel down and finish hollowing out with sandpaper.

John Vella
Posts: 241
Joined: 20 Mar 2017, 22:09
Location: UK

Re: M100S

Post by John Vella »

RobbieB wrote:
22 Jul 2018, 17:20
Ah, another Phoenix rises from the ashes (as does the balsa dust).

Profiling the aileron leading edge shrouds on the right wing - what a faff. The profile is not a straight radius, it changes top to bottom and has to be identical in both wings as the gap at the underside changes depending upon the ailerons position so it's got to be right in both wings.


frise_shroud_rw.JPG


To further complicate matters, you will see from the photos below the gap increases from root to tip. Anyone any ideas as to why?


mesange4.JPG

mesange 7.JPG
Robbie the reason for the increasing gap towards the tip is to increase venting and drag which helps with adverse yaw on rolling the glider. It is of little consequence in our realm of flying. Even the Scale Police would have been very eagle eyed to spot it on the model. Keep going , good work. Regards John.

User avatar
RobbieB
Posts: 579
Joined: 07 Mar 2015, 22:22
Location: North West

Re: M100S

Post by RobbieB »

Thanks for that info John, I knew there had to be a reason for it.

I'm sure you're right, none of this should matter a lot down at our scales but that said, I have no idea how these frise ailerons are going to perform.

Anyway, after the nightmare they have been I'm more than ready for the Scale Police. Certain phrases containing references to personal anatomy and sunshine immediately spring to mind....................

User avatar
B Sharp
Posts: 736
Joined: 19 Mar 2015, 17:18
Location: Perthshire

Re: M100S

Post by B Sharp »

Robbie, I was also worried about the effectiveness or lack of when I built the frise ailerons on my 1:3.5 scale Oly 463. I shouldn't have bothered my little head about them - they handled exactly like ailerons - they banked the model perfectly.
Brian. ;)

User avatar
RobbieB
Posts: 579
Joined: 07 Mar 2015, 22:22
Location: North West

Re: M100S

Post by RobbieB »

Scale Police wrote:
19 Jan 2019, 16:39
Hello, hello, hello! What's all this then?
I just knew it.................................

Brian, it's the large gap that I have concerns about. On the full size you can almost get your hand all the way through from bottom to top. Surely can't be doing the wing's efficiency any favours? Not to mention how far the leading edge of the up-going aileron protrudes below the bottom of the wing.

Carmam-M100-72.JPG

Shroud fitted:

DSC_0082.JPG

User avatar
Peter Balcombe
Posts: 1139
Joined: 18 Mar 2015, 10:13
Location: Clevedon, North Somerset, U.K.

Re: M100S

Post by Peter Balcombe »

Robbie,
I thought that the large amount of up-going aileron LE droop below the wing surface was the main point of the Frise aileron, in order to create drag on that side to counter adverse yaw.

I would have thought that the increasing amount of gap as you go out along the aileron is also likely to be intentional.
Maybe the intention is to take air from the high pressure side of the wing at that point to reduce lift - helping to drop the down-going wing, or even to blow it over the upper surface of the aileron?
I’m sure an aerodynamicist could explain all.

John Vella
Posts: 241
Joined: 20 Mar 2017, 22:09
Location: UK

Re: M100S

Post by John Vella »

Sorry if I am teaching you the obvious Robbie, but here we go . In normal flight the leakage is minimal. On application of a normal aileron the upward going wing on a high AR glider produces more drag than the deflection of the downward going wing due to operating in higher pressure air. This ADVERSE yaw can be overcome usually by differential movement. However the FRISE aileron provides an equally effective solution. On application of upward aileron movement the leading edge does two things by increasing drag (Good for adverse yaw) and vents high pressure air from below the wing to the top of the aileron increasing the downward rolling force. This system is about control effectiveness not just efficiency, especially at higher angles of attack. Regards John.

User avatar
B Sharp
Posts: 736
Joined: 19 Mar 2015, 17:18
Location: Perthshire

Re: M100S

Post by B Sharp »

Robbie, the top surface gap on my Oly 463 is negligible when there is no aileron deflection but the gap between the lower LE of the aileron and the lower wing surface is rather more substantial. This is in order to allow the lower nose of the aileron to rotate upwards into the wing when the surface is deflected downwards (if that makes sense).
When the surface is deflected upwards there is a very substantial portion of the aileron nose protruding below the surface of the wing as well as a mighty gap. This is due to the position of the aileron pivot points on the lower surface of the aileron. (pivot is in the scale position) At the same time the gap on the upper surface between the aileron and the wing opens up and you get a good view of the grass below.
As I said before I was concerned as to the handling and effectiveness but it turned out ok. As john said, the whole point of the frise arrangement was to create drag as well as negative lift. However this is only partially effective in my model and also the full size machine. On my model I still have to put in a chunk of rudder to avoid adverse yaw. This is exactly like the full size Oly463 where it was normal to lead with a bootfull of rudder on the turns to keep the initiation sweet (if my memory serves me well).
Brian. :)
P.S. I am cleaning up my models at the moment. I will try and get some pic of my ailerons later today and post them here if it helps.

User avatar
B Sharp
Posts: 736
Joined: 19 Mar 2015, 17:18
Location: Perthshire

Re: M100S

Post by B Sharp »

I checked my Oly463 wing this afternoon and took a few photos as promised. My memory of the gaps was not as accurate as I thought previously. :o However the amount that the nose of the aileron protrudes below the bottom surface is still quite significant. I hope this is of a little help Robbie.
Brian. :)
Attachments
Upper surface with full aileron deflection up.
Upper surface with full aileron deflection up.
Upper surface with full aileron deflection down.
Upper surface with full aileron deflection down.
Lower Surface with no aileron deflection.
Lower Surface with no aileron deflection.
Lower Surface with full aileron deflection down.
Lower Surface with full aileron deflection down.
Lower Surface with full aileron deflection up.
Lower Surface with full aileron deflection up.
Detail of underside of aileron with full aileron deflection up.
Detail of underside of aileron with full aileron deflection up.

Geoff Pearce
Posts: 427
Joined: 18 Mar 2015, 09:11
Location: SN11 9EE

Re: M100S

Post by Geoff Pearce »

B Sharp wrote:
20 Jan 2019, 16:04
I checked my Oly463 wing this afternoon and took a few photos as promised. My memory of the gaps was not as accurate as I thought previously. :o However the amount that the nose of the aileron protrudes below the bottom surface is still quite significant. I hope this is of a little help Robbie.
Brian. :)
Looks like a good cleaning job Brian :D :lol:

Post Reply