Geoffrey Thorpe
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Everything posted by Geoffrey Thorpe
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Geoffrey Thorpe added a post in a topic Caculating Edge Distance
An AN-6 bolt in double shear should be good for about 16000 pounds. An AN-5 is about 11000. (per attached)
My calculations for my 1300 pound Merlin GT (single strut) comes up to 5100 pound of tensile load in the strut at 3.8 G - but those are my numbers, ymmv, use at your own risk, no warranty expressed or implied, do not attempt at home, etc.
Just off the top of my head, I would guess that the loads on the two struts on something like an Avid would be on the order of 75% front, 25% rear (+- 100% or so).
AN3THRUAN20-REV12.006281.pdf
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Geoffrey Thorpe added a post in a topic switching to nosedragger
If that won't make it scary, nothing will. I would start by fixing this.
Forward CG is not an issue for ground handling. I doubt that you would need mondo springs if you got the tow in fixed. Got a big pipe wrench?
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Geoffrey Thorpe added a post in a topic Fiberglass Methods
If you are not fussy about the surface finish on the mold side, duct tape and packing tape work well as a "mold release". If the surface has too much curve, rip the duct tape into strips.
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Geoffrey Thorpe added a post in a topic Brake lines
They have 2 types of fittings - I believe that these are what are on my ride. http://www.aircraftspruce.com/catalog/hapages/nutsleeveassembly.php
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Geoffrey Thorpe added a post in a topic No N numbers...No problem just don't fly from airports
Would you mind writing up a rough outline of how you were able to accomplish this?
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Geoffrey Thorpe added a post in a topic D-Motor
Specs be here: http://www.d-motor.eu/nl/products-2.htm
Surprised to see someone building a flat head engine. But it is more compact even if the heat losses are higher, I guess we don't care about emissions, and it is a slow rev design...
Flipping through the manual, they recommend auto fuel - period - and a fully synthetic oil. Not so great for applications here in yea olde USA where there is leaded fuel at most airports.
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Geoffrey Thorpe added a post in a topic Power loss. Off field landing...
OK, a day late and a dollar short - I went looking for the weight spec for the floats and found a service bulletin that I had not seen before on checking the float level... http://legacy.rotaxowner.com/si_tb_info/serviceb/sb-912-065ul.pdf
But, back on topic - any landing you walk away from...
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Geoffrey Thorpe added a post in a topic Wing/ Strut bolts
AN bolt specs attached.
AN3THRUAN20-REV12.006281.pdf
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Geoffrey Thorpe added a post in a topic Storing Kitfox does and don't?
Was the engine pickled?
Kinda late, but better than never - drain all fuel from fuel lines, gascolator, carbs. Spray some fogging oil into the cylinders at a minimum. If there was an oil change done when it was put away, fine. If not, consider at least changing it even if the engine is cold.
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Geoffrey Thorpe added a post in a topic "FOXY FLAPPER" FOTOS
I used a panel lift (drywall lift) to hang my wings.
10 minutes of your life you will never get back: https://youtu.be/inHNNG1EDig
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Geoffrey Thorpe added a post in a topic Engine Cowling Woes
Some "free form" hydroforming fwiw...
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Geoffrey Thorpe added a post in a topic Static Port Location
I (currently) use the cabin for the static source. Opening and closing the round pop out vents that I have on the doors makes about a 5 mph change in indicated air speed (IIRC).
I like the idea of cutting an inspection port in the bottom for access as outlined in the directions that were attached.
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Geoffrey Thorpe added a post in a topic Propeller Carving questions
That's the way it was when I bought the airplane. I have no Idea if it may have been painted at some time.
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Geoffrey Thorpe added a topic in "other aircraft your working on"
Propeller Carving questionsI have an old ground adjustable Warp Drive prop that I have never been real excited about - if nothing else, it has a really big clunky hub that has to be wasting a lot of energy just beating up the air...
So, I've been thinking that carving my own might be a fun project. And, the logical first step (at least in my mind) would be figuring out what pitch my current prop is set at. So, measuring tape and bubble protractor in hand, I spent some time at the hangar and came up with the plot of pitch as a function of radius at several points, and this is what I get:
[The "classic prop" line is from a spread sheet that I found online (http://www.nmine.com/propeller.htm)]
The decrease in pitch from my measurements as it gets towards the tip seems odd to me (assuming my calculations are correct). I would guess that it might be that the blade twist was optimized for some pitch other than where I have mine set - I will play with the numbers a bit. But I would think that the pitch distribution can't be helping my performance.
For those that actually know something - does the pitch distribution for the "classic prop" seem reasonable? Does it look like I did something wrong? Comments?
My raw numbers / calculations:
% find the average pitch of a propeller from angles and radial location
% assumes angle of back of blade is the chord angle
% enter data here:
% Angle of hub. degrees (negative means that top of surface is aft of
% bottom)
ah = -8.75;
% Location of angle measurements (inches from center)
dim = [12 18 24 30 36];
% angle of blade at each measurement (degrees) blade 1 and 2 - all
% measurments with blade to port side of the aircraft (leading edge up and level)
ab1m = [20.5 16 10 5 3];
ab2m = [20 16 10 5.5 3];
% end data entry
% correct angles for angle of hub
ab1a = ab1m - ah;
ab2a = ab2m - ah;
% circumfance at each measurement
cir = 2*pi*dim;
% calculate pitch for each point.
p1 = cir.*tand(ab1a);
p2 = cir.*tand(ab2a);
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Geoffrey Thorpe added a post in a topic Hello?
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Geoffrey Thorpe added a post in a topic Bending Long Sheet Metal like Leading Edges
For those who don't get kitplanes
http://raa.ca/magazine_pdf/tech articles/Leading Edge Vacuum Forming.pdf
And, a video: https://youtu.be/2_QWPoFEhWc
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Geoffrey Thorpe added a post in a topic Name this 3 blade prop for me
Pitch is reasonably straight forward to calculate given an actual propeller - set the prop face on a level surface and measure the angle of the back of the blade from horizontal with a bubble protractor at one or more known radii, then: Pitch = tangent(angle)* 2 * pi* radius.
You will find that the pitch likely varies somewhat with radius.
If the propeller is on an airplane, measure the difference in angle between the hub face and the back of the blade...
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Geoffrey Thorpe added a post in a topic Jabiru Props
Hijacking the thread... Do you use a constant pitch (of course the angle changes) from root to tip or do you modify it as a function of diameter?
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Geoffrey Thorpe added a post in a topic Amphibian project resurrection & modifications
Just for the record...
The chances of me ever owning a Catalina are somewhere between slim and none, but none the less, I have really been enjoying reading this thread (and other similar threads) with the pictures of the progress and some discussion about the thought processes to get there. Thanks to all of you for taking the time to post this stuff.
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Geoffrey Thorpe added a post in a topic Ivo in flight adjustable on 582
Well, there is the don't ask don't tell option.
The last issue of Kitplanes addressed the placard idea - the DAR guy says a placard doesn't cut it. But that's an opinion.
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Geoffrey Thorpe added a post in a topic Ivo in flight adjustable on 582
Of course, it can never qualify as an LSA again which may hurt your resale...
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Geoffrey Thorpe added a post in a topic Buying Aerothane
It seemed to be mostly stained - not lifting from the fabric. But I chose to replace the fabric rather than mess around.
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Geoffrey Thorpe added a post in a topic Buying Aerothane
Depends on how much and how often you spill. A leaking full level sender will make a real mess over time. But, I would use it again because it's easy to repair - so far I have had fuel tanks out three times :-(
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Geoffrey Thorpe added a post in a topic Buying Aerothane
It can be a whole lot worse, and it is a whole lot worse.
In addition to being really really bad, it has, and I quote, "Poor warning qualities" which means you don't realize that you are getting nailed. With the polytone, or other old style paints you knew when your respirator was used up by the smell. Not so with the two part urethane. That's why you really, really want a source of outside air.
Paint suit, good gloves, and outside air.
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Geoffrey Thorpe added a post in a topic Borescope Rotax 582
Corrosion or a reflection of the deposits on the top of the piston?
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