Miles M.35 Tandem Wing Build Log

DutchRoll

Well-known member
I had a day off, and I had planned to spend it flying, but winds in the 18-25 mpg made me think that I really didn't want to maiden the Ugly-EZ in those conditions. So instead I started what I thought would be a quick build of the Miles M.35 Tandem wing plane. I posted my results over in the scratch build tonight thread, but since I want to go futher with this plane, I kicked off this Build Log thread.

Wiki Article

The Miles M.35 Tandem Wing was originally conceived in 1942 as a naval fighter that wouldn't require folding wings. However, the manufacturer didn't get approval from the British War Ministry to build the plane and they denied him permission to develop the aircraft for them. That, and some glaring technical reasons, ended the development of this interesting plane.

We'll be getting into the technical reasons as I have to address them in this build log.

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FastCrash45

Elite member
I had a day off, and I had planned to spend it flying, but winds in the 18-25 mpg made me think that I really didn't want to maiden the Ugly-EZ in those conditions. So instead I started what I thought would be a quick build of the Miles M.35 Tandem wing plane. I posted my results over in the scratch build tonight thread, but since I want to go futher with this plane, I kicked off this Build Log thread.

Wiki Article

The Miles M.35 Tandem Wing was orginally concived in 1942 as a naval fighter that wouldn't require folding winds. However, the manufacuter didn't get approval from the British War Ministry to build the plane and they denied him permission to develop the aircraft for them. That, and some glaring technical reasons, ended the development of this interesting plane.

We'll be getting into the technical reasons as I have to address them in this build log.

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That plane has so many possibilities! That looks like a lot of fun to fly.
 

DutchRoll

Well-known member
From the "anybody else scratch building tonight" thread:

"Well, It's a tad bit windy out here on the plains, so Ugly-EZ is sitting this one out today. But free flying time is usable build time, so I'm kit bashing a Miles M.35 tandem wing chuck glider out of black foam board, based on plans for a cable controlled balsa version I found on the interwebs. So far I've got the fuselage and the front wing completed, and I'll turn to the main wing and rudders next. I've sized the build so that I can stuff the B power pod in there if I want to RC it. "

I spent about 6 hours up this point, using the cable control plans that I found over on Aerofred.com as a base. The designer, J. Mchard, had actually done some decent work scaling it down, yet making it so that most measurements were nice round numbers.

Since the front wing was so thin, I went with a simple step air foil.


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DutchRoll

Well-known member
After working for another two hours, I got a main wing bashed out. Except that I didn't measure twice and cut once when it came to the wing tips, and they kinda came up short. I had to cover the missing ends with tape.

The other problem was that when I drew up the wing, I assumed (wrongly) that the Dollar Store foam board was 0.1875 inches (3/16th) thick. It's not - It's 0.177 inches thick! So my wing ended up a little small and a little less thick than it should have been. I think I'll remake the wing, but using the .233 inch thick Ross board for wallymart, increasing both the thickness and the chord to improve the lift.

When I took it out this morning to give it a test flight, the aircraft was balanced slightly nose down (with a nickel) according to the marked CG, except that as soon as I threw it the front wing immediatly stalled and it crashed. It was too tail heavy for the lift the rear wing was giving, so I had to add two large washers to the front wing to get it to settle down and glide.

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DutchRoll

Well-known member
That plane has so many possibilities! That looks like a lot of fun to fly.

Actually, It's very sensitive to changes in CG, making it pitch unstable at times. And the design does have some airwash blanketing issues with the front wing disturbing the air over the rear, causing the rear to stall and drop while the front remains flying.

Once I get the airfoil rebuilt and the CG sorted out, I'm going to see if some vortex generators help with the airflow adhesion to the wing. I need it to fly stable if I am going RC the darn thing, which can be done, according to the literature.
 

DutchRoll

Well-known member
Well, I went outside this evening and gave the M.35 a few more tosses, about 15 or so before the nose was totally stoved in. Turns out that the plane is very sensitive to control input changes from the front wing, certainly for elevator control. I only got about 5 good glides out of it. the rest either pile drove straight in, or stalled at the end and slide back down. This is gonna take more experiments to figure out the flight profile.

Poor Birdy.

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DutchRoll

Well-known member
I was looking over the plans last night, and I realized that I had accidentally also chopped an inch off the trailing edge. No wonder the plane was tail sliding - the CL for the rear wing was too far forward for it's CG. I taped some cardstock to the top of the wing to extend the trailing edge, and it's a little bit better behaved now - but it would be better just to rebuild the goobbered wing entirely.

A straight stall of the front wing just leads to a steady sink rate now, and when I throw it right it glides okay (when I don't throw it right it just pitch poles and flops to the ground). It does still have a tendancy to wobble at certain angles of attack (like an aggressive dutch roll at slow speeds), as if different sections of the two wings are stalling at different times. The front wing's dihedral is pretty mild compared to the aggressive polyhedral of the main wing, so I don't know how that affects the airplane's instability.

I wonder if I need to add some wing fences to help straighten out the airflow?
 
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