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JSteensen
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Posted: 1/30/2012 12:41:12 AM
BTW, JINXER, I don't have the plans uploaded on the wiki yet. I was debating between direct download, and setting up a SVN repository for that. Leaning towards SVN. Wish I had spare keys for Enterprise PDM...ever since I implemented it at work, well, I'm head over heels with it for real work.
JPN
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Posted: 1/30/2012 6:50:17 AM
Originally Posted By JINXR:
Originally Posted By JSteensen:
It really isn't passing the sniff test to me either, but I'm not seeing any obvious failure, and I've used it very accurately in the past to calculate weights.

http://i263.photobucket.com/albums/ii135/jrsteensen/A-Plane%20Build/f3516562.png

http://i263.photobucket.com/albums/ii135/jrsteensen/A-Plane%20Build/8d2f6928.png

http://i263.photobucket.com/albums/ii135/jrsteensen/A-Plane%20Build/dc33b8e1.png

The seat shown is the third picture is just a placeholder. (I haven't decided on a real seat yet, or a harness.) The seat itself is assigned a zero mass with the brackets having normal properties of the 6061-T6.

Looked on GrabCAD and 3dcontentcentral for a normal Walmart 5 gallon gas can to no avail, so I'll need to go buy one and model that to design my fuel system around. (The gas can goes on the little bracket to the rear of the seat.)


Looks like your volume is jacked up. 1530 in³ seems WAY too high.



Calculated volume for solid bar stock, instead of tubing?
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JPN
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Posted: 1/30/2012 7:01:02 AM
[Last Edit: 1/30/2012 7:03:35 AM by JPN]
Originally Posted By AeroE:
You should see what used to pass for scratch built plans. The builder had to know how to build an airplane, the plans were just barely guidelines. I have a set of original Cassutt plans that are the most humorous. The flat patterns for the cowling will fit on an 8 1/2 X 11 inch sheet of paper.

Then there are the original Windwagon plans. They aren't hilarious, they're just plain sad.

A universal problem with plans in the homebuilt airplane world is the lack of checking of the drawings before selling, and then failure to update or correct the drawings as the builders uncover the problems. This is one reason it's impertive to belong to a builder's group.


Drawings for STC'd mods can also be entertaining. Sometimes dimensions are not included. Sometimes dimensions are given as "approximately". Sometimes dimensions are given that are impossible to fit the plane you are working on. One company put out a kit for their mod, with very nice blueprints that unfolded large enough that you could tape them to the leading edges of the wings (too big to get all the drawings on one wing) and easily read whatever section you were working on (once you found it). That company went out of business and sold their STC. The new company issued some engineering orders for improvements to the STC, and supplies the drawings in a tileprint format (a stack of 8.5 x 11 sheets that you have to tape together to get the complete drawing, then use a magnifying glass to read dimensions, part numbers, and station numbers).
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NineLivez
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Posted: 1/30/2012 7:14:48 AM
I have been wanting to build a UL, now you show me one I may be able to afford. My wife might be showing up on your door step to hurt you
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JSteensen
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Posted: 1/30/2012 9:59:19 AM
Originally Posted By JPN:
Originally Posted By JINXR:
Originally Posted By JSteensen:
It really isn't passing the sniff test to me either, but I'm not seeing any obvious failure, and I've used it very accurately in the past to calculate weights.

http://i263.photobucket.com/albums/ii135/jrsteensen/A-Plane%20Build/f3516562.png

http://i263.photobucket.com/albums/ii135/jrsteensen/A-Plane%20Build/8d2f6928.png

http://i263.photobucket.com/albums/ii135/jrsteensen/A-Plane%20Build/dc33b8e1.png

The seat shown is the third picture is just a placeholder. (I haven't decided on a real seat yet, or a harness.) The seat itself is assigned a zero mass with the brackets having normal properties of the 6061-T6.

Looked on GrabCAD and 3dcontentcentral for a normal Walmart 5 gallon gas can to no avail, so I'll need to go buy one and model that to design my fuel system around. (The gas can goes on the little bracket to the rear of the seat.)


Looks like your volume is jacked up. 1530 in³ seems WAY too high.



Calculated volume for solid bar stock, instead of tubing?


The odd part is the main fuselage is calculating to what I would expect it to, using square tubing.
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Posted: 1/30/2012 8:16:07 PM
Originally Posted By JSteensen:
Originally Posted By JPN:
Originally Posted By JINXR:


Looks like your volume is jacked up. 1530 in³ seems WAY too high.



Calculated volume for solid bar stock, instead of tubing?


The odd part is the main fuselage is calculating to what I would expect it to, using square tubing.


Landing gear components tend to be kinda heavy, relative to other airframe components, but those numbers seem way out of proportion for the total weight of the airframe.

If there are no math errors, and the gear is that heavy, you might want to consider something simpler. Simplest ultralight landing gear I've seen, is on the BUG4 and GOAT1. You can find the drawings for them, and pictures of the completed aircraft, by doing a search for "Basic Ultralight Glider" and look for the page by a guy named Sandlin. If I lived closer to the mountains in the eastern end of the state, I'd be building something like a GOAT.
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AZ_Sky
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Posted: 1/30/2012 9:26:09 PM
The $27K (gulp) IO-360 Lycoming engine was just delivered to my workshop this afternoon for my experimental aircraft build.
I hope your build goes well and a lot less expensive!!!

Courage is not the lack of fear. It is acting in spite of it.
~Mark Twain~
JSteensen
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Posted: 1/30/2012 9:30:57 PM
What bird is that?

And too rich for my blood at the moment. Later in life I can enjoy the good things
AZ_Sky
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Posted: 1/30/2012 9:40:55 PM
Originally Posted By JSteensen:
What bird is that?

And too rich for my blood at the moment. Later in life I can enjoy the good things


Vans RV-4:

Courage is not the lack of fear. It is acting in spite of it.
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JSteensen
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Posted: 1/30/2012 9:46:40 PM
What i thought it was. If I get my PPL, that's the bird I really really want.
AZ_Sky
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Posted: 1/30/2012 9:50:53 PM
Originally Posted By JSteensen:
What i thought it was. If I get my PPL, that's the bird I really really want.


Keep up the good work!
Any day defying gravity is better than being stuck on the ground!!!
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flaperon
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Posted: 1/30/2012 10:08:41 PM
Yeah but...number of 447's delivered is in the thousands, number of Hexadynes delivered..maybe what, dozens (being generous) in 10 years! That engine has some very questionable history...

The 447 is a great motor for the weight.

Originally Posted By Keith_J:
Rotax 447? Always have a place to land. Crappy glide ratio and low altitude means you don't have much time to find a suitable landing strip. Plus you will have a helmet fire in trying to figure wind direction+speed.

A Hexadyne P60 would be a better fit. Four-stroke boxer twin, geared. Fuel injected, uses regular pump gasoline. 98 pounds with electric starter.
Yes, more expensive but the 447 has a 300 hour TBO where the P60 has at least 4 times that.


Thanks Myitinaw!
JSteensen
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Posted: 1/30/2012 10:10:38 PM
Plane was built for the Rotax 447. Its already a heavy bum...I am considering going up to the 503 if I can trim enough weight elsewhere....and I can get the right deal.
flaperon
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Posted: 1/30/2012 10:13:17 PM
I've heard that Rotax is discontinuing their two stroke line. There's plenty of used/rebuilt stuff out there.

I've flown behind a Rotax 503 for 11 years and it's never let me down. It's considered the most reliable two stroke by many...

Originally Posted By JSteensen:
I am debating between the Rotax 447, 503-1 and 503-2...I really need to find a solid model of the engines, gearboxes, and electric starts. Contacted Rotax, and they stated they didn't have any models of the airplane engines.


Thanks Myitinaw!
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Posted: 1/30/2012 10:16:39 PM
Sweet...I love my Dynon D-180...

Originally Posted By AZ_Sky:
Originally Posted By JSteensen:
What bird is that?

And too rich for my blood at the moment. Later in life I can enjoy the good things


Vans RV-4:

http://www.pbase.com/terry_56/image/120516853.jpg


Thanks Myitinaw!
JSteensen
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Posted: 1/30/2012 10:33:42 PM

Originally Posted By flaperon:
I've heard that Rotax is discontinuing their two stroke line. There's plenty of used/rebuilt stuff out there.

I've flown behind a Rotax 503 for 11 years and it's never let me down. It's considered the most reliable two stroke by many...

Originally Posted By JSteensen:
I am debating between the Rotax 447, 503-1 and 503-2...I really need to find a solid model of the engines, gearboxes, and electric starts. Contacted Rotax, and they stated they didn't have any models of the airplane engines.



Funny you should mention that.

Just got an email back from Rotax. They dont have model of thier two stroke engines available, and the 447 and 503 are discontinued.

Absolutely no idea how to power this thing, considering Rotax is/was pretty much the safe standard on these birds until now - I haven't even heard of anyone flying anything other than a rotax.
ske714
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Posted: 1/31/2012 2:44:56 AM
Have you considered a diesel? I've never looked into it, but there are a few out there that might be interesting.
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Posted: 1/31/2012 9:38:07 AM

Originally Posted By ske714:
Have you considered a diesel? I've never looked into it, but there are a few out there that might be interesting.

No way. This is an ULTRA LIGHT. Meaning 40 Hp or more and under 100 pounds. Which means a propeller speed reduction unit is a must. The torsional vibration of diesels is very harsh, meaning significant over-design of the gear train is needed. Even a cog belt.
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Posted: 1/31/2012 10:25:06 AM
Originally Posted By AZ_Sky:
The $27K (gulp) IO-360 Lycoming engine was just delivered to my workshop this afternoon for my experimental aircraft build.
I hope your build goes well and a lot less expensive!!!

http://www.pbase.com/terry_56/image/141216927.jpg


Wow - sweet engine! That RV will seriously scoot along with that pulling it.

Budget has me looking at Corvair power if I go the ELSA route in the next year. They've been developing a good reputation when built right (I saw one guy with over 1,000 hours on his), and parts are cheap!
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Posted: 1/31/2012 10:39:10 AM
I don't understand why a guy would purposely ignore all the actual knowledge and experience on this topic and strike out on his own.

As an engineer, I can assure you that most engineering is historical or empirical, calculated by trial and error.

Also, the present cost to build airplanes isn't based on extravagance, it's a matter of trial and error as well.
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Posted: 1/31/2012 11:13:09 AM
Originally Posted By cyborg543:
I don't understand why a guy would purposely ignore all the actual knowledge and experience on this topic and strike out on his own.

As an engineer, I can assure you that most engineering is historical or empirical, calculated by trial and error.

Also, the present cost to build airplanes isn't based on extravagance, it's a matter of trial and error as well.


Not sure I am tracking you....
cyborg543
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Posted: 1/31/2012 11:39:32 AM
[Last Edit: 1/31/2012 11:43:53 AM by cyborg543]
Originally Posted By JSteensen:
Originally Posted By cyborg543:
I don't understand why a guy would purposely ignore all the actual knowledge and experience on this topic and strike out on his own.

As an engineer, I can assure you that most engineering is historical or empirical, calculated by trial and error.

Also, the present cost to build airplanes isn't based on extravagance, it's a matter of trial and error as well.


Not sure I am tracking you....


If I was doing this project, I would find a website of guys who actual build and fly these things, have a lot of experience.

I would ask them what the best book on the topic is and read it cover to cover.

Then I would ask what the best kit for a beginner was.

And I would budget for the actual cost required to build a high quality aircraft, with some of the really tricky work being done by a professional.

A lot of guys hugely underestimate the value of actual experience and grossly over-estimate their ability to figure things out on their own, this airplane project being an extreme case.

When I wanted to learn rifle shooting, I bought a book by an olympic shooting coach. Why try to start at zero when I can tap into the coach's lifetime of experience for $20?


Also, building airplanes is a mature technology. If everyone else's plane is costing twice as much as you budgeted, you have to figure there is some reason.
JSteensen
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Posted: 1/31/2012 12:14:53 PM
Originally Posted By cyborg543:
Originally Posted By JSteensen:
Originally Posted By cyborg543:
I don't understand why a guy would purposely ignore all the actual knowledge and experience on this topic and strike out on his own.

As an engineer, I can assure you that most engineering is historical or empirical, calculated by trial and error.

Also, the present cost to build airplanes isn't based on extravagance, it's a matter of trial and error as well.


Not sure I am tracking you....


If I was doing this project, I would find a website of guys who actual build and fly these things, have a lot of experience.

I would ask them what the best book on the topic is and read it cover to cover.

Then I would ask what the best kit for a beginner was.

And I would budget for the actual cost required to build a high quality aircraft, with some of the really tricky work being done by a professional.

A lot of guys hugely underestimate the value of actual experience and grossly over-estimate their ability to figure things out on their own, this airplane project being an extreme case.

When I wanted to learn rifle shooting, I bought a book by an olympic shooting coach. Why try to start at zero when I can tap into the coach's lifetime of experience for $20?

Also, building airplanes is a mature technology. If everyone else's plane is costing twice as much as you budgeted, you have to figure there is some reason.


Not derailing the thread any further, but thats why I belong to several groups of guys who build and fly these birds. Not everything in the world has to be built by engineers. However, I do appreciate engineers on specific advice. (For example one of the aerospace and one of the mechanical engineers at work have really helped me talking about materials and forces that will be acting on the bird, in an effort to lighten it.) I'm not totally reinventing the wheel here, just adding some features I like.

I am constantly referencing EAA articles on construction to learn how to do things.
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Posted: 1/31/2012 12:26:10 PM
[Last Edit: 1/31/2012 12:28:22 PM by AeroE]
Originally Posted By JSteensen:
Originally Posted By cyborg543:
I don't understand why a guy would purposely ignore all the actual knowledge and experience on this topic and strike out on his own.

As an engineer, I can assure you that most engineering is historical or empirical, calculated by trial and error.

Also, the present cost to build airplanes isn't based on extravagance, it's a matter of trial and error as well.


Not sure I am tracking you....


He believes airplanes can be designed and built from handbook formulas like using a building code, he doesn't understand the low number of this airplane that are flying, he doesn't understand the nature of the homebuilt airplane, and I suspect he doesn't understand the critical importance of weight.

The engineering of aircraft is missing a component available in nearly every other field of engineering; there are no books containing the "architecture" of what makes a successful airplane. Actually there are, but they all include simplified information that is really intended for first order design to help get something layed as a starting place that needs to be followed up with the tweaks to optimize the airplane. Virtually no text deals with the idea that a low performance airplane can be designed good enough in the first pass, so experience is required to understand those steps. Or just big enough balls to plow ahead in ignorance; that occurs often enough.


You need to avail yourself of other information about design and construction outside what you will find in Sport Aviation or Experimenter.

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JSteensen
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Posted: 1/31/2012 1:41:29 PM
Originally Posted By AeroE:
Originally Posted By JSteensen:
Originally Posted By cyborg543:
I don't understand why a guy would purposely ignore all the actual knowledge and experience on this topic and strike out on his own.

As an engineer, I can assure you that most engineering is historical or empirical, calculated by trial and error.

Also, the present cost to build airplanes isn't based on extravagance, it's a matter of trial and error as well.


Not sure I am tracking you....


He believes airplanes can be designed and built from handbook formulas like using a building code, he doesn't understand the low number of this airplane that are flying, he doesn't understand the nature of the homebuilt airplane, and I suspect he doesn't understand the critical importance of weight.

The engineering of aircraft is missing a component available in nearly every other field of engineering; there are no books containing the "architecture" of what makes a successful airplane. Actually there are, but they all include simplified information that is really intended for first order design to help get something layed as a starting place that needs to be followed up with the tweaks to optimize the airplane. Virtually no text deals with the idea that a low performance airplane can be designed good enough in the first pass, so experience is required to understand those steps. Or just big enough balls to plow ahead in ignorance; that occurs often enough.


You need to avail yourself of other information about design and construction outside what you will find in Sport Aviation or Experimenter.



Totally agreed. I take on projects like this to learn as much about the processes involved as I can. The ends are just a benefit...the ride is what I enjoy the most. With my F-16 Block 60 sim I built, I taught myself CAD, electronics (I designed and built the layer between the switches and gauges and the PC driving the sim), and CAM to CNC the structure, panels, controls, etc.

This is just the next logical level, even though the electronics will be much simpler, even as much as i would LOVE to have a glass cockpit, its totally overkill for this sort of deal.
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Posted: 1/31/2012 3:58:14 PM
[Last Edit: 1/31/2012 3:59:15 PM by CSM]
Craigslist a Garmin 396 or one of the lesser models for your ultralight. :D

They work pretty well for nav in the Cessnas I fly. And recently I have seen the 296s for sale for a few hundred.
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JSteensen
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Posted: 1/31/2012 4:39:05 PM
[Last Edit: 1/31/2012 4:39:51 PM by JSteensen]
Actually a GPS was pretty high on the list, though depending on if Im going to fly it from some random place in the desert versus out at the uncontrolled airstrip in bisbee will be the difference between slapping my car GPS with topo maps on it, or getting an aviation gps.

Probably get a cheap aviation one, and panel mount it with a external GPS antenna for shits and giggles.
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Posted: 1/31/2012 5:02:20 PM
Originally Posted By JSteensen:
Actually a GPS was pretty high on the list, though depending on if Im going to fly it from some random place in the desert versus out at the uncontrolled airstrip in bisbee will be the difference between slapping my car GPS with topo maps on it, or getting an aviation gps.

Probably get a cheap aviation one, and panel mount it with a external GPS antenna for shits and giggles.


If you really wanted to get into it, the Garmin has a pseudo panel that might be fun. A slightly slow updating speed, altimeter, and VSI.
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Posted: 1/31/2012 5:19:37 PM
I was going to go with a GPS, Grand Rapids EIS, and analogue alt, airspeed, compass, fuel (since the tank is directly behind me, it would be hard to check it in flight), and a clock. Going to frame mount a handheld aviation radio with helicopter plug on it for my helmet I use for SAR. (HGU-56/P) Mount circuit breakers as necessary.
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Posted: 2/8/2012 1:54:04 PM
Well, starting to work on the cockpit structure some more. Haven't had much time to work on it - had to go to Dallas for several days because my grandad had to have a quintuple heart bypass. His biggest concern is if he can still ride his Harley. He was up the day after surgery walking around.
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Posted: 2/8/2012 2:03:33 PM
[Last Edit: 2/8/2012 2:16:26 PM by stangboy555]

Originally Posted By AZ_Sky:
The $27K (gulp) IO-360 Lycoming engine was just delivered to my workshop this afternoon for my experimental aircraft build.
I hope your build goes well and a lot less expensive!!!

http://www.pbase.com/terry_56/image/141216927.jpg

Thats the same engine used in the Cessna 172s right? Seems a little big for the project you're working on?

ETA, well.. I guess they're both about the same size and application... and more power never hurts
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Posted: 2/8/2012 3:02:32 PM
Originally Posted By stangboy555:

Originally Posted By AZ_Sky:
The $27K (gulp) IO-360 Lycoming engine was just delivered to my workshop this afternoon for my experimental aircraft build.
I hope your build goes well and a lot less expensive!!!

http://www.pbase.com/terry_56/image/141216927.jpg

Thats the same engine used in the Cessna 172s right? Seems a little big for the project you're working on?

ETA, well.. I guess they're both about the same size and application... and more power never hurts


Actually, not quite.
I had the engine built with 10:1 pistons instead of the standard 8.5:1 pistons, I also had a roller tappet modification installed, and the fuel injector is an Airflow Performance.
Ly-Con in CA built the engine, the dyno report shows that the engine develops 221HP @2700RPM, about 40HP more than stock.

The empty weight of a typical Cessna 172 is somewhere around 1700lbs, the empty weight of my RV-4 is ~950lbs.
The wingspan of the Cessna is ~36 feet, mine is ~23 feet.
Cessna cruise speed is ~122 ktas, my RV-4 is still unknown but will probably be ~180 ktas.
Courage is not the lack of fear. It is acting in spite of it.
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Posted: 2/8/2012 3:03:48 PM
AZ, so when you flying down this direction? That's a pretty bird.
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Posted: 2/8/2012 3:06:40 PM

Originally Posted By AZ_Sky:
Originally Posted By stangboy555:

Originally Posted By AZ_Sky:
The $27K (gulp) IO-360 Lycoming engine was just delivered to my workshop this afternoon for my experimental aircraft build.
I hope your build goes well and a lot less expensive!!!

http://www.pbase.com/terry_56/image/141216927.jpg

Thats the same engine used in the Cessna 172s right? Seems a little big for the project you're working on?

ETA, well.. I guess they're both about the same size and application... and more power never hurts


Actually, not quite.
I had the engine built with 10:1 pistons instead of the standard 8.5:1 pistons, I also had a roller tappet modification installed, and the fuel injector is an Airflow Performance.
Ly-Con in CA built the engine, the dyno report shows that the engine develops 221HP @2700RPM, about 40HP more than stock.

The empty weight of a typical Cessna 172 is somewhere around 1700lbs, the empty weight of my RV-4 is ~950lbs.
The wingspan of the Cessna is ~36 feet, mine is ~23 feet.
Cessna cruise speed is ~122 ktas, my RV-4 is still unknown but will probably be ~180 ktas.

And on 100LL? Impressive.

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AZ_Sky
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Posted: 2/8/2012 3:07:16 PM
[Last Edit: 2/8/2012 3:10:12 PM by AZ_Sky]
Originally Posted By JSteensen:
AZ, so when you flying down this direction? That's a pretty bird.


Thanks -
Ha!
I'm in the same boat as you right now.
I have to finish building the thing then fly the time off it.
Probably won't be till late this year....

ETA: The plane in my avatar is the first airplane I built - it's an RV-3 with an O-320 engine.
Courage is not the lack of fear. It is acting in spite of it.
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Posted: 2/8/2012 3:08:06 PM
Originally Posted By AZ_Sky:
Originally Posted By stangboy555:

Originally Posted By AZ_Sky:
The $27K (gulp) IO-360 Lycoming engine was just delivered to my workshop this afternoon for my experimental aircraft build.
I hope your build goes well and a lot less expensive!!!

http://www.pbase.com/terry_56/image/141216927.jpg

Thats the same engine used in the Cessna 172s right? Seems a little big for the project you're working on?

ETA, well.. I guess they're both about the same size and application... and more power never hurts


Actually, not quite.
I had the engine built with 10:1 pistons instead of the standard 8.5:1 pistons, I also had a roller tappet modification installed, and the fuel injector is an Airflow Performance.
Ly-Con in CA built the engine, the dyno report shows that the engine develops 221HP @2700RPM, about 40HP more than stock.

The empty weight of a typical Cessna 172 is somewhere around 1700lbs, the empty weight of my RV-4 is ~950lbs.
The wingspan of the Cessna is ~36 feet, mine is ~23 feet.
Cessna cruise speed is ~122 ktas, my RV-4 is still unknown but will probably be ~180 ktas.


Such is why RV's are really cool planes, Id like to fly one someday.
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JSteensen
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Posted: 2/8/2012 3:19:55 PM
Originally Posted By AZ_Sky:
Originally Posted By JSteensen:
AZ, so when you flying down this direction? That's a pretty bird.


Thanks -
Ha!
I'm in the same boat as you right now.
I have to finish building the thing then fly the time off it.
Probably won't be till late this year....

ETA: The plane in my avatar is the first airplane I built - it's an RV-3 with an O-320 engine.


No, our worlds are far apart. My bird exists solely as bits and bytes at the moment.

The RV-3 is a second favorite - I'm a huge fan of tandem two-seaters. My absolute dream bird would be an L-39Z. A while back I got to go visit the Patriots Acrobatic Teams hanger and crawl through the L-39 and the head A&P's personal MIG-17 all day. I was amped up for weeks. Though, when I first crawled into the L-39, had one foot on the seat, stepped up in, looked down, and found the pin to the (hot) ejection seat on the floor of the bird. Talk about a moment of excitement...
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Posted: 2/8/2012 3:24:32 PM
Originally Posted By AZ_Sky:
Originally Posted By stangboy555:

Originally Posted By AZ_Sky:
The $27K (gulp) IO-360 Lycoming engine was just delivered to my workshop this afternoon for my experimental aircraft build.
I hope your build goes well and a lot less expensive!!!

http://www.pbase.com/terry_56/image/141216927.jpg

Thats the same engine used in the Cessna 172s right? Seems a little big for the project you're working on?

ETA, well.. I guess they're both about the same size and application... and more power never hurts


Actually, not quite.
I had the engine built with 10:1 pistons instead of the standard 8.5:1 pistons, I also had a roller tappet modification installed, and the fuel injector is an Airflow Performance.
Ly-Con in CA built the engine, the dyno report shows that the engine develops 221HP @2700RPM, about 40HP more than stock.

The empty weight of a typical Cessna 172 is somewhere around 1700lbs, the empty weight of my RV-4 is ~950lbs.
The wingspan of the Cessna is ~36 feet, mine is ~23 feet.
Cessna cruise speed is ~122 ktas, my RV-4 is still unknown but will probably be ~180 ktas.


And unless Cessna went to an O-360 when they put the 172 back into production, the most powerful 'stock' 172 has a 160hp O-320 and a fixed pitch prop. From the picture of your cockpit, it appears you also have an advantage in the prop department. What kinda climb rate are you expecting from this little hotrod?
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AZ_Sky
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Posted: 2/8/2012 3:32:43 PM
[Last Edit: 2/8/2012 3:33:37 PM by AZ_Sky]
Originally Posted By JPN:
Originally Posted By AZ_Sky:
Originally Posted By stangboy555:

Originally Posted By AZ_Sky:
The $27K (gulp) IO-360 Lycoming engine was just delivered to my workshop this afternoon for my experimental aircraft build.
I hope your build goes well and a lot less expensive!!!

http://www.pbase.com/terry_56/image/141216927.jpg

Thats the same engine used in the Cessna 172s right? Seems a little big for the project you're working on?

ETA, well.. I guess they're both about the same size and application... and more power never hurts


Actually, not quite.
I had the engine built with 10:1 pistons instead of the standard 8.5:1 pistons, I also had a roller tappet modification installed, and the fuel injector is an Airflow Performance.
Ly-Con in CA built the engine, the dyno report shows that the engine develops 221HP @2700RPM, about 40HP more than stock.

The empty weight of a typical Cessna 172 is somewhere around 1700lbs, the empty weight of my RV-4 is ~950lbs.
The wingspan of the Cessna is ~36 feet, mine is ~23 feet.
Cessna cruise speed is ~122 ktas, my RV-4 is still unknown but will probably be ~180 ktas.


And unless Cessna went to an O-360 when they put the 172 back into production, the most powerful 'stock' 172 has a 160hp O-320 and a fixed pitch prop. From the picture of your cockpit, it appears you also have an advantage in the prop department. What kinda climb rate are you expecting from this little hotrod?


Yeah, I'm installing a Hartzell blended airfoil 72" constant speed prop.
I have absolutely no idea of what the end performance is going to be until I fly it for the first time.
The RV-4 with a 180HP fixed pitch wooden prop is spec'd to climb at 2450 fpm, I expect to get better than that.....

Courage is not the lack of fear. It is acting in spite of it.
~Mark Twain~
stangboy555
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Posted: 2/8/2012 4:09:19 PM
I envy you guys, all of my time and money is going to finishing a degree I should have finished 15 years go. I'll be up there soon enough though!

I'm saving all of my nickels and dimes for a Mustang But I'll settle for a DA20!
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Posted: 2/9/2012 4:32:38 PM
Random question: First off, I know this sounds a bit crazy. Can I toss aluminum blades on my miter saw and cut 2x2x.125" 6061-T6 aluminum square tube? I have a cut-off saw from harbor freight, but it doesn't do angles....its fixed straight. I have a fairly nice miter saw and could cut my complex angles MUCH more easily. I'm thinking about ordering all the aluminum for the frame and starting to assemble a little as I go...to keep my interest. This weekend, its all garage organization and prep.
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Posted: 2/10/2012 9:23:04 AM
Yes, a fine saw of 12 or more teeth per inch should work. Be very gentle on the feed and clamp both ends. Aluminum cuts as easy as hardwood but it can dull blades faster. Not to imply you can use wood working tooling in all cases. I've used carbide router bits on aluminum. Glitter shower.

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Posted: 2/10/2012 10:39:45 AM
Hah! I bet. I think I have a CAD addiction....I'm laying out all the workbench and tool locations for my garage....
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Posted: 2/10/2012 12:19:08 PM

Originally Posted By AZ_Sky:

Yeah, I'm installing a Hartzell blended airfoil 72" constant speed prop.
I have absolutely no idea of what the end performance is going to be until I fly it for the first time.
The RV-4 with a 180HP fixed pitch wooden prop is spec'd to climb at 2450 fpm, I expect to get better than that.....


Oh wow, that's incredible.


How did you get into RV-4's in the first place?

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AZ_Sky
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Posted: 2/10/2012 1:14:13 PM
Originally Posted By mtechgunman:

Originally Posted By AZ_Sky:

Yeah, I'm installing a Hartzell blended airfoil 72" constant speed prop.
I have absolutely no idea of what the end performance is going to be until I fly it for the first time.
The RV-4 with a 180HP fixed pitch wooden prop is spec'd to climb at 2450 fpm, I expect to get better than that.....


Oh wow, that's incredible.


How did you get into RV-4's in the first place?



I got my pilot license in 1974 and was flying the usual Whicita Wobble Wings.
I got involved with a group of guys who built and flew these fun, fast, aerobatic experimental aircraft and I was hooked.
I originally was going to build a Midget Mustang I, but then an unfinished project RV-3 became available in my town.
The price was right so I bought it and finished the build in 1987 (that's the one in my avatar).
I've been flying the single place RV-3 ever since, I love the performance and the way it flys!
But - one airplane isn't enough.....
I wanted one to take the girl friend along also so naturally I didn't think any farther then the RV-4 (I don't like side-by-side airplanes).

Courage is not the lack of fear. It is acting in spite of it.
~Mark Twain~
mtechgunman
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Posted: 2/10/2012 1:44:08 PM

Originally Posted By AZ_Sky:
Originally Posted By mtechgunman:

Originally Posted By AZ_Sky:

Yeah, I'm installing a Hartzell blended airfoil 72" constant speed prop.
I have absolutely no idea of what the end performance is going to be until I fly it for the first time.
The RV-4 with a 180HP fixed pitch wooden prop is spec'd to climb at 2450 fpm, I expect to get better than that.....


Oh wow, that's incredible.


How did you get into RV-4's in the first place?



I got my pilot license in 1974 and was flying the usual Whicita Wobble Wings.
I got involved with a group of guys who built and flew these fun, fast, aerobatic experimental aircraft and I was hooked.
I originally was going to build a Midget Mustang I, but then an unfinished project RV-3 became available in my town.
The price was right so I bought it and finished the build in 1987 (that's the one in my avatar).
I've been flying the single place RV-3 ever since, I love the performance and the way it flys!
But - one airplane isn't enough.....
I wanted one to take the girl friend along also so naturally I didn't think any farther then the RV-4 (I don't like side-by-side airplanes).


That is very cool.

I'm in PP training myself. Would love to experience something like this on down the road.
Hey I ain't never coming home
Hey I'll just wander my own road
Hey-hey I can't meet you here tomorrow no, no
Say goodbye don't follow
Misery so hollow
JPN
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Posted: 2/10/2012 2:40:41 PM
Originally Posted By AZ_Sky:
Originally Posted By mtechgunman:

Originally Posted By AZ_Sky:

Yeah, I'm installing a Hartzell blended airfoil 72" constant speed prop.
I have absolutely no idea of what the end performance is going to be until I fly it for the first time.
The RV-4 with a 180HP fixed pitch wooden prop is spec'd to climb at 2450 fpm, I expect to get better than that.....


Oh wow, that's incredible.


How did you get into RV-4's in the first place?



I got my pilot license in 1974 and was flying the usual Whicita Wobble Wings.
I got involved with a group of guys who built and flew these fun, fast, aerobatic experimental aircraft and I was hooked.
I originally was going to build a Midget Mustang I, but then an unfinished project RV-3 became available in my town.
The price was right so I bought it and finished the build in 1987 (that's the one in my avatar).
I've been flying the single place RV-3 ever since, I love the performance and the way it flys!
But - one airplane isn't enough.....
I wanted one to take the girl friend along also so naturally I didn't think any farther then the RV-4 (I don't like side-by-side airplanes).



You coulda had an RV-8!
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Posted: 2/10/2012 2:44:42 PM
Originally Posted By JPN:
Originally Posted By AZ_Sky:
Originally Posted By mtechgunman:

Originally Posted By AZ_Sky:

Yeah, I'm installing a Hartzell blended airfoil 72" constant speed prop.
I have absolutely no idea of what the end performance is going to be until I fly it for the first time.
The RV-4 with a 180HP fixed pitch wooden prop is spec'd to climb at 2450 fpm, I expect to get better than that.....


Oh wow, that's incredible.


How did you get into RV-4's in the first place?



I got my pilot license in 1974 and was flying the usual Whicita Wobble Wings.
I got involved with a group of guys who built and flew these fun, fast, aerobatic experimental aircraft and I was hooked.
I originally was going to build a Midget Mustang I, but then an unfinished project RV-3 became available in my town.
The price was right so I bought it and finished the build in 1987 (that's the one in my avatar).
I've been flying the single place RV-3 ever since, I love the performance and the way it flys!
But - one airplane isn't enough.....
I wanted one to take the girl friend along also so naturally I didn't think any farther then the RV-4 (I don't like side-by-side airplanes).



You coulda had an RV-8!


Actually, my next one will be a Harmon Rocket III - much sexier.....

Courage is not the lack of fear. It is acting in spite of it.
~Mark Twain~
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Posted: 2/10/2012 2:49:20 PM
Originally Posted By JPN:
Originally Posted By AZ_Sky:
Originally Posted By stangboy555:

Originally Posted By AZ_Sky:
The $27K (gulp) IO-360 Lycoming engine was just delivered to my workshop this afternoon for my experimental aircraft build.
I hope your build goes well and a lot less expensive!!!

http://www.pbase.com/terry_56/image/141216927.jpg

Thats the same engine used in the Cessna 172s right? Seems a little big for the project you're working on?

ETA, well.. I guess they're both about the same size and application... and more power never hurts


Actually, not quite.
I had the engine built with 10:1 pistons instead of the standard 8.5:1 pistons, I also had a roller tappet modification installed, and the fuel injector is an Airflow Performance.
Ly-Con in CA built the engine, the dyno report shows that the engine develops 221HP @2700RPM, about 40HP more than stock.

The empty weight of a typical Cessna 172 is somewhere around 1700lbs, the empty weight of my RV-4 is ~950lbs.
The wingspan of the Cessna is ~36 feet, mine is ~23 feet.
Cessna cruise speed is ~122 ktas, my RV-4 is still unknown but will probably be ~180 ktas.


And unless Cessna went to an O-360 when they put the 172 back into production, the most powerful 'stock' 172 has a 160hp O-320 and a fixed pitch prop. From the picture of your cockpit, it appears you also have an advantage in the prop department. What kinda climb rate are you expecting from this little hotrod?


Actually they did.

The IDP built Skyhawks have the IO-360 limited to 2400RPM/160HP or the Skyhawk SP with the same engine 2700RPM/180HP.

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Posted: 2/13/2012 11:24:43 AM
Well, I'm thinking about having the frame gussets water-jetted only because the gussets constrain the shape of the frame and they need to be very very accurate. Considered CNC Plasmajet, but I am concerned with the HAZ in the 6061-T6, even though I can get around it by undersizing the holes and oversizing at the edges, but that means manual finish....which would somewhat defeat the point anyways.

Anybody know of some one off waterjet places? The gussets nest on a 36x48x.125" plate of 6061-T6.
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