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pwood66889

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Feb 10, 2007
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1,698
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Sopchoppy, Florida, USA
I have one set of Graham Lee plans and I feel they are complete enough. His main "value add" is his construction methods and tips.
Percy in SE Bama
 

jany77

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Joined
Jul 5, 2005
Messages
402
Location
california
im familiar with his kind of gusset and tubing construction i was more or less wondering if there is any example of miranda flying i contacted lee's but didnot get any answer yet thank you guys
 

Double Eagle

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Joined
Jan 10, 2008
Messages
57
Location
Albany WI
I made the leap. I have the plans and an engine, now to be the first to build a Graham Lee Miranda, who is going to be number 2?
 

Bill-Higdon

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Joined
Feb 6, 2011
Messages
773
Location
Salem, Oregon, USA
Ryan,

There used to be a a Miranda group on Yahho, after Grahams death it seemed to die, a few years back someone posted about starting abuild but nothing more.

Bill
 

karmarepair

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HBA Supporter
Joined
Jan 13, 2011
Messages
229
Location
United States
I
Ryan,

There used to be a a Miranda group on Yahoo, after Grahams death it seemed to die, a few years back someone posted about starting a build but nothing more.

Bill
I've looked at it. Nobody posted much of anything, and nothing for a long time. I'm on my own IF I start. I've been looking at that airplane for a LONG time, I figured it was time to scratch that itch.
 

karmarepair

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Jan 13, 2011
Messages
229
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United States
Finally got the plans from the Lee family.

It's a booklet of design sketches, really. Nothing like the level of detail of, say, the Sonex scratch build plans I've been working with lately, where every part is described, and there is a clear work breakdown to the plans themselves. Examples of details left to the builder that I've noticed thus far include control system positive mechanical stops, and any sort of detail of the fuel system, this last in part because Lee allows for a wide variety of engines. I could not figure out how he figured on "suitable engines" that are 70-80 lbs. different in installed weight. The answer is varying the sweep of the lower wing. Light engine and pilot - sweep the lower wing back. Heavy/Heavy - lower wing spars stay straight. Pretty clever.

You CAN build from these plans, but you'd need to keep your Tony Bingelis library close at hand to work out a lot of the details.

I was thinking of using a direct drive Kohler CH750 driving a 54 inch two bladed Ultra-Prop running 3600 RPM, but Lee is quite vocal that he designed this ship for a slower turning, 72-84 inch propeller. So I'll see how much horsepower it will take to drive a longer prop at somewhere around 2000-2300 RPM, and look for an engine that will give the desired HP at no more than 4000 RPM, and use a re-drive to slow it down.
 

rv7charlie

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Joined
Nov 17, 2014
Messages
939
Location
Jackson
I was thinking of using a direct drive Kohler CH750 driving a 54 inch two bladed Ultra-Prop running 3600 RPM, but Lee is quite vocal that he designed this ship for a slower turning, 72-84 inch propeller. So I'll see how much horsepower it will take to drive a longer prop at somewhere around 2000-2300 RPM, and look for an engine that will give the desired HP at no more than 4000 RPM, and use a re-drive to slow it down.
Just use the HP recommended, at engine weight recommended, with the recommended prop dia. (Reduction as needed to get rpm right.)

On a relatively slow plane like that, it would take more HP with a smaller prop than with the recommended dia. According to the aero guys, it's a 'mass flow' thing; moving a lot of air mass (large dia prop) at a slow speed is more efficient than moving less air (smaller diameter) at higher speed. I can tell you from personal experience with a much faster a/c (RV4), that with the same engine, just going from a 68" dia to a 72" dia makes a *big* difference in takeoff roll, and costs nothing on the top end. For something like one of the Lee designs, with top speed likely to be my climb speed, prop diameter will be a huge factor in performance. For another data point, one of the Kolb Twinstar owners installed a direct drive VW, and had horrible performance. He added the weight of a reduction drive & large dia prop, and turned the plane into a great performer.

FWIW...
 

karmarepair

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Jan 13, 2011
Messages
229
Location
United States
Other missing detail: aileron cables. If I built, I'll copy something out of the flying and Gliding manuals.

On propping and powering, the Ultraprop II comes 66 inches and they say absorbs 25 hp/blade. Ivo and Warp Drive make 72 inch blades at a higher price point. A big block Kohler or Briggs would make that easily with a redrive to slow things down, and a mildly breathed on Kohler CH750 MIGHT. Still thinking and researching.
 

pictsidhe

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Joined
Jul 15, 2014
Messages
8,650
Location
North Carolina
The valley engineering big twin was rated at 32hp continously. They had 40 and 50hp peak versions. Weight was 120lb.
Maybe you have more experience with such engines than they did and can get a little more. But it won't be much and it won't be easy.
 

karmarepair

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229
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United States
The valley engineering big twin was rated at 32hp continuously. They had 40 and 50hp peak versions. Weight was 120lb.
Maybe you have more experience with such engines than they did and can get a little more. But it won't be much and it won't be easy.
I used to look down my nose at Valley Engineering, until I watched the videos of The Old Man talking about the Backyard Flyer and the Big Twin, and then the scales fell from my eyes. May His Memory Be For A Blessing; Gene Smith really did know what he was about.

Just one example: I could not figure out what was going on with this landing gear. He explains it in this video - he's using a curved piece of aluminum as a tension spring. Light, simple, relatively aerodynamic.

And his system for dealing with torsional vibrations is very, very clever.
=================================

I have no illusions about getting more than 30 continuous out of a CH750, maybe a little bit more with water injection for METO <grinning>. I'd cut down the pitch of whatever prop I'd end up using to suit the available horsepower. The designer says "30-50 HP". When I get around to it, I'll do a drag build-up to see if I believe him.

And if anybody has a good idea how to ovalize the full length of a 1-5/8 OD X 0.058 wall 6061-T6 lift strut, I'm all ears. The V-Struts and the spar for the lower wing are all flattened in this manner.
 

pictsidhe

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Jul 15, 2014
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8,650
Location
North Carolina
I'd be looking at rollers. Might need a few passes depending how flat you want it. Be careful not to go below the minimum bend radius anywhere.
 
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