Backcountry Pilot • Do we have an EAA Tech Counselor on board

Do we have an EAA Tech Counselor on board

Sometimes the most fun way to get into the backcountry, Part 103 Ultralights and Light Sport Aircraft have their own considerations.
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Do we have an EAA Tech Counselor on board

I need a Tech Counselor near Boise. Hopefully with a set of scales or access to some.

Thanks
EB
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Re: Do we have an EAA Tech Counselor on board

That is a post that needs more info. We know you are looking for a plane so what are you looking at.

Tim
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Re: Do we have an EAA Tech Counselor on board

If you need a set of scales to weigh a plane and can't find them locally, you can rent them through Avery Tool, that's how I weighed my experimental. They ship em to you UPS with instructions and you use the same crate to ship them back. I kept them a week for $100.

http://www.averytools.com/
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Re: Do we have an EAA Tech Counselor on board

qmdv wrote:That is a post that needs more info. We know you are looking for a plane so what are you looking at.

Tim

Hey Tim, yer smoking me out here. Yeah, Charlie (S-12 Flyer) turned me on to it. It's never been flown, built by a Boeing Engineer who passed away before beginning the 40 hour flight test program. It's out of budget (of course) but not by much. I have a tech guy here but he'll charge me to ride up there. Much better to get a local guy. I want to see how much weight it gained with the Jabiru. Ordinarily I wouldn't consider a Jabiru but this one is a virgin. I can make my own mistakes with the overheating problems. The Son thinks the engine was purchased in '06 or '07. I've asked him to get me the serial number. I'd truck it home so I could do the 40 hour fly off here. That's all in the plus column as far as I'm concerned.
http://www.barnstormers.com/classified_ ... +2200.html
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Re: Do we have an EAA Tech Counselor on board

Wish I were closer.. I have 4 , 2000 lb digital readout scales that display in2 lb increments and custom made ramps so you can just roll the plane onto them instead of jacking it up..... I am afraid the freight alone would make them less attractive then locally rented ones.

Ben.
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Re: Do we have an EAA Tech Counselor on board

You don't need a certified scale for what you're asking for. Just have the owner get three bathroom scales and put one under each wheel. If you want to calculate the balance, you'll also need to know the distances of the wheels from the datum point.
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Re: Do we have an EAA Tech Counselor on board

kevbert wrote:You don't need a certified scale for what you're asking for. Just have the owner get three bathroom scales and put one under each wheel. If you want to calculate the balance, you'll also need to know the distances of the wheels from the datum point.

So Kev, it's got to be more complicated than the sum of the scale readings right? I've seen threads on the process but never paid any attention. Somebody got a link? I just want to know the empty weight (I'll guess how much fuel is in there). The builder had just begun ground testing when he went West. I'm going to call the factory tomorrow. They are 20 miles away. They might have somebody that I can lean on.
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Re: Do we have an EAA Tech Counselor on board

a+b+c :lol:

That plane should be light enough to use bathroom scales.

If deriving the balance from the weight, you have to make sure all the scales are at the same height, i.e., that the plane is level.

edit: since you just want the empty weight (accurate to within a couple of lbs.) you can just weigh each wheel separately with one scale. When only one wheel is up on the scale, you're tipping some of the weight onto the other wheels, so put a 2x4 or something under the other wheels to make it more accurate.
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Re: Do we have an EAA Tech Counselor on board

kevbert wrote:a+b+c :lol:

That plane should be light enough to use bathroom scales.

If deriving the balance from the weight, you have to make sure all the scales are at the same height, i.e., that the plane is level.
It's supposed to weigh 450lbs. I doubt it. Hopefully it hasn't gotten to 625 or something.
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Re: Do we have an EAA Tech Counselor on board

Emory Bored wrote:I need a Tech Counselor near Boise. Hopefully with a set of scales or access to some.

Thanks
EB



Is airplane in Sparks ? I may be going to Washington --have scales and W&B computer program . I do W&B ,Prop balance , Prebuys , Maintenance,rigging , Airworthiness etc. See my web site http: edmaircraft.com
Have tools can travel
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Re: Do we have an EAA Tech Counselor on board

182 STOL driver wrote:
Emory Bored wrote:I need a Tech Counselor near Boise. Hopefully with a set of scales or access to some.

Thanks
EB



Is airplane in Sparks ? I may be going to Washington --have scales and W&B computer program . I do W&B ,Prop balance , Prebuys , Maintenance,rigging , Airworthiness etc. See my web site http: edmaircraft.com
Have tools can travel
It's in Boise STOL driver. 0 TTAF 0 Time SFNEW. It doesn't need an annual, it needs an evaluation. I'll call the factory tomorrow. It's 20 miles or so from the airplane. Thanks for the offer.
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Re: Do we have an EAA Tech Counselor on board

kevbert wrote:a+b+c :lol:

That plane should be light enough to use bathroom scales.

If deriving the balance from the weight, you have to make sure all the scales are at the same height, i.e., that the plane is level.

edit: since you just want the empty weight (accurate to within a couple of lbs.) you can just weigh each wheel separately with one scale. When only one wheel is up on the scale, you're tipping some of the weight onto the other wheels, so put a 2x4 or something under the other wheels to make it more accurate.
Kool! Makes sense.
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Re: Do we have an EAA Tech Counselor on board

That's bloody adorable... good for you! A little mini L-3 Grasshopper :)

Please understand that the Jabiru cooling problems may be solve-able with a little cleverness and some cowling work. I am by no means a Jab expert but I have several decent ideas on cooling systems. PM me if you get the airplane and want to chat about this.

In brief, a standard downdraft cooling system on a slow-flying, high AOA airplane is 2.5 strikes against getting good cooling. Relocating the air exits, or switching to updraft cooling, can easily make a huge difference in mass airflow through the fins.

OK... just took a look at the Barnstormer photos again. If you will excuse my butting in, I saw some things that COULD cause potential cooling issues.

1) The air inlets in the front of the cowl are sized for a much faster airplane. MUCH smaller than most other 60-80 HP aircraft installations. Not enough air getting in during slow flight.
2) The position of the air inlets on the very top edge on the nose cowl puts them right in a LOW pressure area when the airplane is in a climb or slow flight attitude. Low air pressure at the opening means air is not going to have any motivation to enter the cooling system.
3) The large vertical rectangular opening, to blow air on the oil pan, is a possible problem. That opening is in the CORRECT location for a high pressure air inlet. BUT... unless that "oil pan air duct" is kept absolutely separate from the entire CYLINDER cooling system, then you strand a good chance of having that high pressure air pressurizing the lower cooling plenum section of the cylinder cooling system.
4) The air exit on the bottom of the cowling at the firewall is in HIGHER than ambient pressure when the airplane is climbing.\\

The air is SUPPOSED to come in the front inlets, and create high pressure in the upper plenum chamber above the engine cylinders. You're SUPPOSED to have lower pressure underneath the cylinders because the air in that lower plenum chamber is sucked out the back at the bottom of the firewall.

Now imagine you are flying at a high "deck angle", like takeoff or climb.

A) The air glances off the front cowl at the air intakes, but the front of the cowling is like the front of an airfoil at high angle of attack... there's low pressure instead of high pressure. So little or no air is going in to pressurize the upper plenum chamber. Especially because the inlet holes are so small.

B) The bottom of the cowling is not in much of a low pressure area in climb attitude, because the relative wind is "hitting" or impacting the bottom of the fuselage harder than it is on the top. So instead of low pressure at the exit helping the air flow out, you have higher pressure, and little or no "suction" to pull the air through the cooling system.

C) IF the oil pan cooling duct is not completely sealed and kept separate, the high pressure air coming in through the one good hi-pressure inlet can "fill up" and pressurize the area underneath the cylinders, further opposing the correct cooling flow.

The point of all this egregious filibustering is not to frighten you, but to show you that there are ways to address these issues. If you do have cooling problems, my strongest choice on an experimental is updraft cooling, like on Peter Garrison's brilliant Melmoth http://www.melmoth2.com/texts/CoolingFlow.htm Short of that, we can re-locate your air exits in a lower pressure area, and motivate the air to come in at the front a little better than the way it's designed now. I'll be happy to offer some ideas and work with you on it when you get the airplane if it is of any value.
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Re: Do we have an EAA Tech Counselor on board

Have you asked the seller for a copy of the weight and balance? I would think the builder filled one out.
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Re: Do we have an EAA Tech Counselor on board

The cowling on that plane looks almost exactly like the cowling on a friends Avid mk IV with a Jabaru. I'd bet it is based from the same cowling. The only difference is he does not have the big chin scoop. He has a NACA duct going to an oil cooler in the chin position.

(He has no cooling issues.)
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Re: Do we have an EAA Tech Counselor on board

EZFlap wrote:That's bloody adorable... good for you! A little mini L-3 Grasshopper :)

Please understand that the Jabiru cooling problems may be solve-able with a little cleverness and some cowling work. I am by no means a Jab expert but I have several decent ideas on cooling systems. PM me if you get the airplane and want to chat about this. <snip> I'll be happy to offer some ideas and work with you on it when you get the airplane if it is of any value.
I just wrote a monster reply to this but sent it off to cyberhell by accident. Yes, I understand where you are going with all that. Here is how Jabiru did the CH-701 cooling.
Image The Pre 201 Mooney system closed off the entire top half of the engine and used a very large opening behind the propeller. Jabiru has all kinds of stuff on the top of the engine making that more difficult so they use these fiberglass plenums to contain the high pressure air and direct it to the REAR of the engine and then out via the rear of the cowl. <edit> Maybe those little cardboard gizmos are supposed to direct the air up and over the cylinders and then down through the fins? I dunno. But I agree that the cowl opening looks too small I think. The Early Mooney cowl was almost, but not quite as large the Comanche/Skybolt one.
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Re: Do we have an EAA Tech Counselor on board

Av8r3400 wrote:The cowling on that plane looks almost exactly like the cowling on a friends Avid mk IV with a Jabaru. I'd bet it is based from the same cowling. The only difference is he does not have the big chin scoop. He has a NACA duct going to an oil cooler in the chin position.

(He has no cooling issues.)
Who is that guy? He's the dude that wrote up the full on test program for his install but I can't find it. Do you remember the thread I'm talking about?
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Re: Do we have an EAA Tech Counselor on board

EB
Don't be afraid of updraft cooling!
Some of the big engine twins with high HP and big Turbo's use the updraft cooling to make it work by getting all of that air around the engine cooled before going around the cylinders.
GT
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Re: Do we have an EAA Tech Counselor on board

Updraft cooling is a viable option for this applicaion... A big plus is it will help defrost the windscreen... A big negative is if you get an oil leak the windscreen will turn into a big pair of foogles... [-X

Ben.
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Re: Do we have an EAA Tech Counselor on board

Updraft cooling is a viable option for this applicaion... A big plus is it will help defrost the windscreen... A big negative is if you get an oil leak the windscreen will turn into a big pair of foogles...

Ben.

Even with that he should be able to open the door and wipe it off!!!! :mrgreen:
GT
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